Archive for the ‘metastases’ Category

Preventing Surgery-Induced Cancer Metastasis

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Posted 23 Mar 2012 — by James Street
Category metastases, Surgery

Steven Nemeroff, ND

The article you are about to read is earth-shattering. It provides overwhelming and compelling data that surgery itself is a significant cause of metastasis.

The good news is that a wide variety of methods have been identified to protect against surgically-induced recurrence and metastasis. Armed with this knowledge, a cancer patient can follow simple steps ahead of time to dramatically improve their odds of a cure. There is so much convincing data provided in the following article that it could be expanded into an entire book!

You would think that cancer surgeons would figure this out themselves. After all, everything discussed in the following chapter is based on what is published in the peer-reviewed scientific literature. Sadly, the assembly-line mentality of conventional doctors too often results in these important decisions being overlooked. As you will read, it is critical that the right choices be made before surgery in order to derive optimal benefits.

It is our sincere desire that the following chapter will educate not only patients, but also their surgeons in a way that will revolutionize the way cancer surgeries are planned and carried out in the future. If you are a newly diagnosed cancer patient, the suggestions made in this article are available right now to reduce painful and life-threatening complications, while simultaneously protecting against surgically-induced metastasis and recurrence of the primary tumor.

Cancer Surgery: What You Need to Know Ahead of Time

The surgical removal of the primary tumor has been the cornerstone of treatment for the great majority of cancers. The rationale for this approach is straightforward: if you can get rid of the cancer by simply removing it from the body, then a cure can likely be achieved. Unfortunately, this approach does not take into account that after surgery the cancer will frequently metastasize (spread to different organs). Quite often the metastatic recurrence is far more serious than the original tumor. In fact, for many cancers it is the metastatic recurrence—and not the primary tumor—that ultimately proves to be fatal.1

In a shocking irony, a growing body of scientific evidence has revealed that cancer surgery can increase the risk of metastasis.2 This would fly in the face of conventional medical thinking, but the facts are undeniable.

To gain a better understanding of how surgery can increase the risk of metastasis, let’s first discuss the actual process of cancer metastasis. A complicated sequence of events must occur in order for cancer to spread to another part of the body.2 Isolated cancer cells that break away from the primary tumor must first breach the connective tissue immediately surrounding the cancer. Once the cancer cell has broken free of the surrounding connective tissue, the next step is to enter a blood or lymphatic vessel. This is easier said than done, as entry into a blood vessel requires the cancer cell to secrete enzymes that degrade the basement membrane of the blood vessel.3 Entry into a blood vessel is vitally important for the aspiring metastatic cancer cell, since it uses the bloodstream as a highway for transportation to other vital organs of the body—such as the liver, brain, or lungs—where it can form a new deadly tumor.

Now that the lone cancer cell has finally entered the bloodstream, its problems have only just begun. Traveling within the bloodstream can be a hazardous journey for cancer cells. Turbulence from the fast moving blood can damage and destroy the cancer cell. Furthermore, cancer cells must avoid detection and destruction from white blood cells circulating in the blood stream.

To complete its voyage, the rogue cancer cell must adhere to the lining of the blood vessel, where it degrades through and exits the basement membrane of the blood vessel. Its final task is to burrow through the surrounding connective tissue to arrive at the organ that is its final destination. Now the cancer cell can multiply and form a growing colony that serves as the foundation for a new metastatic cancer. Time is working against these solitary cancer cells. This entire sequence of events must happen quickly, since these cells have a limited life span.1

We now see that cancer metastasis is a complicated and difficult process. Fraught with peril, very few free-standing cancer cells survive this arduous journey.2 The probability of cancer cells surviving this journey and forming new metastases can be increased by anything that serves to make this process easier.

In a groundbreaking study published in the medical journal Annals of Surgery in 2009, researchers reported that cancer surgery itself can create an environment in the body that greatly lessens the obstacles to metastasis that cancers cells must normally face.2

Just as concerning is the revelation that cancer surgery can produce an alternate route of metastasis that bypasses natural barriers. During cancer surgery, the removal of the tumor almost always disrupts the structural integrity of the tumor and/or the blood vessels feeding the tumor. This can lead to an unobstructed dispersal of cancer cells into the bloodstream, or seeding of these cancer cells directly into the chest or abdomen.4-7 This surgery-induced “alternate route” can greatly simplify the path to metastasis.

To illustrate, a study published in the British Journal of Cancer in 2001 compared the survival of women with breast cancer who had their tumors removed surgically, to the survival of women with breast cancer who did not have surgery. As expected, the findings established that surgery substantially improved survival in the early years.

However, further analysis of the data determined that women who had surgery had a spike in their risk of death at eight years that was not evident in the group who did not have surgery.8 In their interpretation of the results, the authors of the study stated: “A reasonable hypothesis to explain the observed patterns of the hazard functions [risk of cancer death] is to assume that…primary tumor removal may result in sudden acceleration of metastatic process…”

Another group of researchers commenting on a study examining the surgical treatment of colon cancer were far bolder in their conclusions: “This finding strongly supports that surgery alters the natural course of the disease by elongating life expectancy in the greater part of the patient population, but also by simultaneously shortening survival in a smaller subset of patients. Thus, both experimental and clinical evidence support that surgery, although greatly reducing tumor mass and potentially curative, paradoxically can also augment metastasis development.”2

Given these disturbing findings, what can individuals undergoing surgery for their cancers do to protect themselves against an increased risk of metastasis? A worthwhile strategy would be to examine all of the mechanisms by which surgery promotes metastasis, and then create a comprehensive plan that counteracts each and every one of these mechanisms.

 

What You Need to Know: Cancer Surgery
  • Surgical removal of cancer typically provides the best chance of disease-free survival.
  • A growing body of evidence suggests that cancer surgery itself may increase the risk of metastasis (spread to other areas) via numerous mechanisms including: increasing cancer cell adhesion, suppressing immune function, promoting angiogenesis, and stimulating inflammation.
  • Since metastatic disease is often deadlier than the original tumor, it is important to utilize preventive strategies to prevent cancer metastasis.
  • Steps to help prevent cancer metastasis include: combating cancer cell adhesion, supporting immune health, heightening immune surveillance, inhibiting angiogenesis, minimizing inflammation, and choosing surgeons and anesthesiologists who utilize advanced techniques that may reduce metastatic risk.
  • Certain nutrients, drugs, types of anesthesia, and surgical techniques are associated with reduced risk of metastasis.

Surgery Increases Cancer Cell Adhesion

One mechanism by which surgery increases the risk of metastasis is by enhancing cancer cell adhesion.9 Cancer cells that have broken away from the primary tumor utilize adhesion to boost their ability to form metastases in distant organs. These cancer cells must be able to clump together and form colonies that can expand and grow. It is unlikely that a single cancer cell will form a metastatic tumor, just as one person is unlikely to form a thriving community. Cancer cells use adhesion molecules—such as galectin-3—to facilitate their ability to clump together. Present on the surface of cancer cells, these molecules act like velcro by allowing free-standing cancer cells to adhere to each other.10 Cancer cells circulating in the bloodstream also make use of galectin-3 surface adhesion molecules to latch onto the lining of blood vessels.11 The adherence of circulating tumor cells (CTC) to the blood vessel walls is an essential step for the process of metastasis. Just like a person sliding down an icy hill has no hope of stopping if they cannot grab onto something, a cancer cell that cannot adhere to the blood vessel wall will just continue to wander through the blood stream incapable of forming metastases. Unable to latch onto the wall of the blood vessel, these circulating tumor cells become like “ships without a port” and are unable to dock. Eventually, white blood cells circulating in the bloodstream will target and destroy the CTC. If the CTC successfully bind to the blood vessel wall and burrow their way through the basement membrane, they will then utilize galectin-3 adhesion molecules to adhere to the organ to form a new metastatic cancer.10

Combating Cancer Cell Adhesion

Regrettably, research has shown that cancer surgery increases tumor cell adhesion. In one experiment that mimicked surgical conditions, scientists reported that the binding of cancer cells to the blood vessel walls was increased by 250%, compared to cancer cells not exposed to surgical conditions.12 Therefore, it is critically important for the person undergoing cancer surgery to take measures that can help to neutralize the surgery-induced increase in cancer cell adhesion. Fortunately, a natural supplement called modified citrus pectin (MCP) can do just that. Citrus pectin—a type of dietary fiber—is not absorbed from the intestine. However, modified citrus pectin has been altered so that it can be absorbed into the blood and exert its anti-cancer effects. The mechanism by which modified citrus pectin inhibits cancer cell adhesion is by binding to galectin-3 adhesion molecules on the surface of cancer cells, thereby preventing cancer cells from sticking together and forming a cluster.13 Modified citrus pectin can also inhibit circulating tumor cells from latching onto the lining of blood vessels. This was demonstrated by an experiment in which modified citrus pectin blocked the adhesion of galectin-3 to the lining of blood vessels by an astounding 95%. Modified citrus pectin also substantially decreased the adhesion of breast cancer cells to the blood vessel walls.13

Impressive research has documented the power of modified citrus pectin to directly inhibit cancer metastasis. In a study published in the Journal of the National Cancer Institute, modified citrus pectin was administered to rats that were injected with prostate cancer cells, while rats not receiving modified citrus pectin served as the control group. Lung metastasis was noted in 93% of the control group, whereas only 50% of the modified citrus pectin group experienced lung metastasis. Even more noteworthy was the finding that the modified citrus pectin group had an 89% reduction in the size of the metastatic colonies, compared to the control group.14 In a similar experiment, mice injected with melanoma cancer cells that were fed modified citrus pectin experienced a greater than 90% reduction in lung metastasis compared to the control group.15

After these exciting findings in animal research, modified citrus pectin was then put to the test in men with prostate cancer. In this trial, 10 men with recurrent prostate cancer received modified citrus pectin (14.4 g per day). After one year, a considerable improvement in cancer progression was noted, as determined by a reduction of the rate at which the prostate-specific antigen (PSA) level increased.16 This was followed by a study in which 49 men with prostate cancer of various types were given modified citrus pectin for a four-week cycle. After two cycles of treatment with modified citrus pectin, 22% of the men experienced a stabilization of their disease or improved quality of life; 12% had stable disease for more than 24 weeks. The authors of the study concluded that “MCP (modified citrus pectin) seems to have positive impacts especially regarding clinical benefit and life quality for patients with far advanced solid tumor.”17

Please remember that these prostate cancer study subjects already suffered from advanced disease. It would appear more logical if these patients had initiated modified citrus pectin supplementation before surgical procedures to prevent metastatic colonies from being established, as was done in the successful laboratory studies.

In addition to modified citrus pectin, a well-known over-the-counter medication can also play a pivotal role in reducing cancer cell adhesion. Cimetidine—commonly known as Tagamet®—is a drug historically used to alleviate heartburn. A growing body of scientific evidence has revealed that cimetidine also possesses potent anti-cancer activity. Cimetidine inhibits cancer cell adhesion by blocking the expression of an adhesive molecule—called E-selectin—on the surface of cells lining blood vessels.15 Cancers cells latch onto E-selectin in order to adhere to the lining of blood vessels.18 By preventing the expression of E-selectin, cimetidine significantly limits the ability of cancer cell adherence to the blood vessel walls. This effect is analogous to removing the velcro from the blood vessels walls that would normally enable circulating tumor cells to bind.

Cimetidine’s potent anti-cancer effects were clearly displayed in a report published in the British Journal of Cancer in 2002. In this study, 64 colon cancer patients received chemotherapy with or without cimetidine (800 mg per day) for one year. The 10-year survival for the cimetidine group was almost 90%. This is in stark contrast to the control group, which had a 10-year survival of only 49.8%. Remarkably, for those patients with a more aggressive form of colon cancer, the 10-year survival was 85% in those treated with cimetidine compared to a dismal 23% in the control group.19 The authors of the study concluded, “Taken together, these results suggested a mechanism underlying the beneficial effect of cimetidine on colorectal cancer patients, presumably by blocking the expression of E-selectin on vascular endothelial [lining of blood vessels] cells and inhibiting the adhesion of cancer cells.” These findings were supported by another study with colorectal cancer patients wherein cimetidine given for just seven days at the time of surgery increased three-year survival from 59% to 93%!20

This data provides a compelling case for cancer patients, at least five days prior to surgery, to ingest at least 14 grams of modified citrus pectin and 800 mg of cimetidine daily. This combination regimen may be followed for a year or longer to reduce metastatic risk.

Preventing Surgery-Induced Immune Suppression

The essential role the immune system plays in combating cancer cannot be overstated. Although there are many aspects of the immune system that come into play when fighting cancer, the role of the natural killer cell predominates. Natural killer (NK) cells are a type of white blood cell tasked with seeking out and destroying cancer cells. Research has shown that NK cells can spontaneously recognize and kill a variety of cancer cells.21

To illustrate the importance of NK cell activity in fighting cancer, a study published in the journal Breast Cancer Research and Treatment examined NK cell activity in women shortly after surgery for breast cancer. The researchers reported that low levels of NK cell activity were associated with an increased risk of death from breast cancer.22 In fact, reduced NK cell activity was a better predictor of survival than the actual stage of the cancer. In another alarming study, individuals with reduced NK cell activity before surgery for colon cancer had a 350% increased risk of metastasis during the following 31 months!23

The likelihood of surgery-induced metastasis requires the immune system to be highly active and vigilant in seeking out and destroying renegade cancer cells during the perioperative period (the time immediately before and after surgery). Tragically, numerous studies have documented that cancer surgery results in a substantial reduction in NK cell activity.6,7,24,25 In an investigation having ominous implications, NK cell activity in women having surgery for breast cancer was reduced by over 50% on the first day after surgery.24 In light of this mounting evidence, a group of researchers stated: “We therefore believe that shortly after surgery, even transitory immune dysfunction might permit neoplasms [cancer] to enter the next stage of development and eventually form sizable metastases.”7

The surgical procedure itself reduces NK activity. This NK cell-impairing effect that occurs immediately after surgery could not happen at a worse possible time. NK cell activity falters when it is most needed to fight metastasis. The surgery-induced increased risk of metastasis combined with a reduction in NK cell activity can have disastrous consequences for the person undergoing cancer surgery. With that said, the perioperative period presents a window of opportunity to actively strengthen immune function by enhancing NK cell activity. Fortunately, numerous nutraceutical, pharmaceutical, and medical interventions known to enhance NK cell activity are available to the person undergoing cancer surgery.

One prominent natural supplement that can increase NK cell activity is PSK, (protein-bound polysaccharide K) a specially prepared extract from the mushroom Coriolus versicolor. PSK has been shown to enhance NK cell activity in multiple studies.26-29 PSK’s ability to enhance NK cell activity helps to explain why it has been shown to dramatically improve survival in cancer patients. For example, 225 patients with lung cancer received radiation therapy with or without PSK (3 grams per day). For those with more advanced Stage 3 cancers, more than three times as many individuals taking PSK were alive after five years (26%), compared to those not taking PSK (8%). PSK more than doubled five-year survival in those individuals with less advanced Stage 1 or 2 disease (39% vs.17%).30

A group of colon cancer patients were randomized to receive chemotherapy alone or chemotherapy plus PSK, which was taken for two years. The group receiving PSK had an exceptional 10-year survival of 82%. Sadly, the group receiving chemotherapy alone had a 10-year survival of only 51%.31 In a similar trial reported in the British Journal of Cancer in 2004, colon cancer patients received chemotherapy alone or combined with PSK (3 grams per day) for two years. In the group with a more dangerous Stage 3 colon cancer, the five-year survival was 75% in the PSK group. This compared to a five-year survival of only 46% in the group receiving chemotherapy alone.32 Research has confirmed that PSK also improves survival in cancers of the breast, stomach, esophagus, and uterus.33-36

Other nutraceuticals that have been documented to increase NK cell activity are garlic, glutamine, IP6 (inositol hexaphosphate), AHCC (active hexose correlated compound), and lactoferrin.37-41 One experiment in mice with breast cancer found that glutamine supplementation resulted in a 40% decrease in tumor growth paired with a 2.5-fold increase in NK cell activity.40

Scientists in Germany explored the effects of mistletoe extract on NK cell activity in 62 patients undergoing surgery for colon cancer. The participants were randomized to receive an intravenous infusion of mistletoe extract immediately before they were given general anesthesia, or were given general anesthesia alone. Measurements of NK cell activity were taken before and 24 hours after surgery. As expected, the group that did not receive mistletoe experienced a 44% reduction in NK cell activity 24 hours after surgery. Interestingly, the scientists reported that the group receiving mistletoe did not experience a significant decrease in NK cell activity after surgery. They went on to conclude that “perioperative infusion of mistletoe extracts can prevent a suppression of NK cell activity in cancer patients.”42

Pharmaceuticals used to increase NK cell activity include interferon-alpha and granulocyte-macrophage colony-stimulating factor. These drugs were shown to prevent surgery-induced immune suppression when given perioperatively.43,44 Another immune boosting drug to consider in the perioperative setting may be interleukin-2.45

At least five days prior to surgery, it would appear logical to institute a natural killer (NK) cell-enhancing program involving nutrients like PSK, lactoferrin, glutamine, and others. Drugs such as interleukin-2 and granulocyte-macrophage colony-stimulating factor are approved in the United States, but health insurance does not usually cover them for the perioperative purposes suggested here. To receive a free copy of the latest dosing recommendations for these nutrients and drugs, call 1-800-841-5433 or log on to our Cancer Surgery Special Report.

Heightening Immune Surveillance with Cancer Vaccines

An enlightened medical approach to cancer treatment involves the use of cancer vaccines. The concept is the same as using vaccines for infectious diseases, except that tumor vaccines target cancer cells instead of a virus. Another distinguishing feature of tumor vaccines is that while viral vaccines are created from a generic virus, tumor vaccines are autologous, that is, they are produced from a person’s own cancer cells removed during surgery. This is a critical distinction since there can be considerable genetic differences between cancers. This highly individualized cancer vaccine greatly amplifies the ability of the immune system to identify and target any residual cancer cells present in the body. Cancer vaccines provide the immune system with the specific identifying markers of the cancer that can then be used to mount a successful attack against metastatic cancer cells.

Autologous cancer vaccines have been studied extensively, with the most encouraging results noted in randomized, controlled clinical trials including more than 1,300 colorectal cancer patients in which tumor vaccines were given after surgery. These trials reported reduced recurrence rates and improved survival.46 Unlike chemotherapy, which can cause severe side effects and toxicity, cancer vaccines are a gentle therapy with proven long-term safety.47

In a landmark study reported in 2003, 567 individuals with colon cancer were randomized to receive surgery alone, or surgery combined with vaccines derived from their own cancer cells. The median survival for the cancer vaccine group was over 7 years, compared to the median survival of 4.5 years for the group receiving surgery alone. The five-year survival was 66.5% in the cancer vaccine group, which dwarfed the 45.6% five-year survival for the group receiving surgery alone.48 This glaring difference in five-year survival clearly displays the power of individually-tailored cancer vaccines to greatly focus a person’s own immunity to target and attack residual metastatic cancer cells.

Cancer Surgery, Angiogenesis, and Metastasis

Cancers employ a clever strategy in their quest to grow and thrive within the body. Angiogenesis is the process by which new blood vessels are formed from pre-existing blood vessels. The formation of new blood vessels is a normal and necessary process for childhood growth and development, as well as for wound healing. Unfortunately, cancers hijack this otherwise normal process in order to increase blood supply to the tumor. The formation of new blood vessels supplying the tumor is an absolute requirement for successful metastasis since tumors cannot grow beyond the size of a pinhead (i.e., 1-2mm) without expanding their blood supply.49,50

It might be surprising to learn that the presence of the primary tumor serves to inhibit the growth of metastatic cancer elsewhere in the body. The primary tumor produces anti-angiogenic factors which restrict the growth of metastases.51-54 These anti-angiogenic factors inhibit the formation of new blood vessels to potential sites of metastasis. Regrettably, the surgical removal of the primary cancer also results in the removal of these anti-angiogenic factors, and the growth of metastasis is no longer inhibited. With these restrictions lifted, it is now easier for small sites of metastatic cancer to attract new blood vessels that promote their growth.55 Indeed, these concerns were voiced by researchers who declared that “… removal of the primary tumor might eliminate a safeguard against angiogenesis and thus awaken dormant micrometastasis [small sites of metastatic cancer].”7

As if the loss of angiogenic inhibition by the primary tumor were not enough of a problem, it turns out the surgery causes another angiogenic predicament. After surgery, levels of factors that increase angiogenesis—also known as vascular endothelial growth factor (VEGF)—are significantly elevated. This can result in an increased formation of new blood vessels supplying areas of metastatic cancer. A group of scientists summarized this research quite well when they asserted that “after surgery, the angiogenic balance of pro- and antiangiogenic factors is shifted in favor of angiogenesis to facilitate wound healing. Especially levels of vascular endothelial growth factor (VEGF) are persistently elevated. This may not only benefit tumor recurrence and the formation of metastatic disease, but also result in activation of dormant micrometastases.”2

Given the metastatic cancer’s need for an expanding blood supply, inhibition of angiogenesis would certainly be an integral part of a comprehensive strategy to combat surgery-induced metastasis. To that end, various nutrients have been shown to inhibit VEGF. These include soy isoflavones (genistein), silibinin (a component of milk thistle), chrysin, epigallocatechin gallate (EGCG) from green tea, and curcumin.56-62

In one experiment, EGCG—the active constituent of green tea—was administered to mice with stomach cancer. The results demonstrated that EGCG reduced the tumor mass by 60%, while also reducing the concentration of blood vessels feeding the tumor by 38%. Remarkably, EGCG decreased the expression of VEGF in cancer cells by an astounding 80%! The authors of the study concluded “EGCG inhibits the growth of gastric cancer by reducing VEGF production and angiogenesis, and is a promising candidate for anti-angiogenic treatment of gastric cancer.”56

In the evaluation of the research pertaining to curcumin’s anti-angiogenic effects, researchers at Emory University School of Medicine noted that “Curcumin is a direct inhibitor of angiogenesis and also downregulates various proangiogenic proteins like vascular endothelial growth factor…” Additionally, the scientists remarked, “Cell adhesion molecules are upregulated in active angiogenesis and curcumin can block this effect, adding further dimensions to curcumin’s antiangiogenic effect.” In conclusion, they commented that “Curcumin’s effect on the overall process of angiogenesis compounds its enormous potential as an antiangiogenic drug.”44

Five days prior to surgery, the patient may consider supplementing with standardized green tea extract, curcumin, soy genistein extract and other nutrients that suppress VEGF and thus may help protect against angiogenesis. To receive a free copy of the latest dosing recommendations for these nutrients, call 1-800-841-5433 or log on to our Cancer Surgery Special Report.

The Choice of Surgical Anesthesia Can Influence Metastasis

The conventional medical approach to surgical anesthesia has been the use of general anesthesia during surgery, followed by intravenous morphine after surgery for pain control. The conventional approach, however, may not be the optimal approach for preventing surgery-induced metastasis. The use of morphine directly after surgery poses significant problems. At a time when immune function is already suppressed, morphine further weakens the immune system by diminishing NK cell activity.63 Surgical anesthesia has also been shown to weaken NK cell activity.64 One study found that morphine increased angiogenesis and stimulated the growth of breast cancer in mice. The researchers concluded: “These results indicate that clinical use of morphine could potentially be harmful in patients with angiogenesis-dependent cancers.”65

Given the inherent problems associated with the use of morphine and anesthesia, researchers have explored other approaches to surgical anesthesia and pain control. One novel approach is the use of conventional general anesthesia combined with regional anesthesia, which refers to anesthesia that only affects a specific part of the body. The benefits achieved with this approach are two-fold: the use of regional anesthesia reduces the amount of general anesthesia required during surgery, as well as decreasing the amount of morphine needed after surgery for pain control.55

This elegant approach to surgical anesthesia and pain control has been validated in scientific studies. In one experiment, cancerous mice received surgery with general anesthesia alone or combined with regional anesthesia. The scientists reported that the addition of regional anesthesia to general anesthesia “markedly attenuates the promotion of metastasis by surgery.” Regional anesthesia reduced 70% of the metastasis-promoting effects of surgery caused by general anesthesia alone.66

Doctors at Pennsylvania State University College of Medicine compared NK cell activity in patients receiving general or regional anesthesia for abdominal surgery. NK cell activity dropped substantially in the general anesthesia group, while NK cell activity was preserved at pre-operative levels in the group that received regional anesthesia.67 Building upon these encouraging findings, researchers then explored if regional anesthesia can affect metastasis in women undergoing surgery for breast cancer. In a pioneering study, 50 women having breast cancer surgery with general anesthesia combined with regional anesthesia were compared to 79 women who received general anesthesia during their breast cancer surgery followed by morphine for pain control. The type of regional anesthesia used is called a paravertebral block, which involves the injection of a local anesthetic around the spinal nerves between the vertebral bones of the spine. After a follow-up period of nearly three years, dramatic differences were noted between the two groups. Only 6% of patients who received regional anesthesia experienced a recurrence, compared to a 24% risk of metastatic recurrence in the group that did not receive regional anesthesia. Stated differently, women who received regional and general anesthesia had a 75% decreased risk for metastatic cancer. These findings led researchers to proclaim that regional anesthesia for breast cancer surgery “markedly reduces the risk of recurrence or metastasis during the initial years following surgery.”55

Surgeons at Duke University Medical Center compared regional anesthesia alone to general anesthesia in women having surgery for breast cancer. The surgeons reported that while 39% of the general anesthesia group required medication for nausea and vomiting, only 20% of the regional anesthesia group needed this medication. Narcotic medication was needed for pain control after surgery in 98% of the general anesthesia group, compared to only 25% of the regional anesthesia group. And 96% of the women receiving regional anesthesia had returned home within a day after surgery, compared with 76% of the women who received general anesthesia. The surgeons concluded that regional anesthesia “can be used to perform major operations for breast cancer with minimal complications… Most importantly, by reducing nausea, vomiting, and surgical pain, paravertebral block [regional anesthesia] markedly improves the quality of operative recovery for patients who are treated for breast cancer and therefore provides the patient with the choice to return home as early as desired after surgery.”68

The results of these studies have vast implications for those undergoing cancer surgery, as a group of researchers enthusiastically announced: “As regional techniques [anesthesia]… are easy to implement, inexpensive, and do not pose a threat greater than general anesthesia, it would be easy for anesthesiologists to implement them, thus reducing the risk of disease recurrence and metastasis.”55

Finally, those requiring morphine for pain control after surgery can consider asking their doctor for a medication called tramadol instead. Unlike morphine, tramadol does not suppress immune function.69 On the contrary, tramadol has been shown to stimulate NK cell activity. In one experiment, tramadol blocked the formation of lung metastasis induced by surgery in rats. Tramadol also prevented the surgery-induced suppression of NK cell activity.70

Less Invasive Surgery Reduces Risk of Metastasis

Surgery places an enormous physical stress upon the body. There is considerable scientific evidence supporting that surgeries that are less invasive—and therefore less traumatic—pose less risk of metastasis, compared to more invasive and traumatic surgery. Laparoscopic surgery is one type of minimally invasive surgery, in which operations in the abdomen, pelvis, and other regions are performed through small incisions, as compared to the much larger incisions needed in traditional “open” surgeries.

A study published in the prestigious medical journal The Lancet compared laparoscopic to open surgery to remove part of the colon (colectomy) in patients with colon cancer. In contrast to the group receiving traditional open surgery, the laparoscopic surgery group had a 61% decreased risk of cancer recurrence coupled with a 62% decreased risk of death from colon cancer. The surgeons concluded that laparoscopic colectomy is more effective than open colectomy for treatment of colon cancer as assessed by tumor recurrence and cancer-related survival.71 A long-term follow-up of these patients (median time 95 months) reported a 56% decreased risk of death from colon cancer for laparoscopic surgery as compared to traditional open surgery.72 Another comparison of laparoscopic surgery to open surgery for colon cancer reported a five-year survival rate of 64.1% for the laparoscopic group, and a five-year survival rate of 58.5% for the group receiving open surgery.73

Minimally invasive surgery has produced substantial improvements in survival for those with lung cancer. Video-assisted thoracoscopic surgery (VATS), a minimally invasive surgery, was compared to traditional open surgery for removing lung tumors (lobectomy). The five-year survival from lung cancer was 97% in the VATS group. This greatly contrasts the 79% five-year survival in the open surgery group.74

Commenting on the use of minimally invasive surgery for lung cancer, surgeons at Cedars-Sinai Medical Center stated that minimally invasive surgery for lung cancer “… can be performed safely with proven advantages over conventional thoracotomy [chest surgery] for lobectomy: smaller incisions, decreased postoperative pain,…decreased blood loss, better preservation of pulmonary function, and earlier return to normal activities… the evidence in the literature is mounting that VATS may offer reduced rates of complications and better survival.”75

Administering Chemo and Radiation Therapies Prior to Surgery
Doctors at the University of North Carolina School of Medicine studied the use of combined radiation and chemotherapy prior to surgery for individuals with esophageal cancer. Twenty-six patients received surgery alone, while 30 patients received radiation and chemotherapy followed by surgery. The group receiving combined treatment had a five-year survival of 39%, while the group treated with surgery alone experienced a five-year survival of only 16%.99

A study published in the New England Journal of Medicine in 2006 compared treatment with surgery alone to treatment with chemotherapy—given both directly before and after surgery—in patients with stomach or esophageal cancer. The five-year survival for the group receiving surgery and chemotherapy was 36%, compared to a five-year survival of 23% in the group receiving surgery alone.100

Research also supports the use of chemotherapy and radiation therapy during the critical perioperative period. In one study, 544 patients with stomach cancer received combined chemotherapy and radiation therapy shortly after surgery. Survival comparisons were made with a similar group of 446 patients with stomach cancer treated with surgery alone. Postoperative chemotherapy and radiation led to a dramatic improvement in survival. The group treated with surgery alone had a median survival of only 62.6 months, compared to a median survival of 95.3 months in the group receiving postoperative radiation and chemotherapy.101 A similar study also demonstrated improved survival with the use of postoperative radiation and chemotherapy compared to surgery alone.102

Inflammation and Metastasis

Cancer surgery causes an increased production of inflammatory chemicals, such as interleukin-1 and interleukin-6.76-78 These chemicals are known to increase the activity of cyclooxygenase-2 (COX-2). A highly potent inflammatory enzyme, COX-2 plays a pivotal role in promoting cancer growth and metastasis.

This was evident in an article appearing in the journal Cancer Research that found levels of COX-2 in pancreatic cancer cells to be 60 times greater than in normal pancreatic cells.79 Levels of COX-2 were 150 times higher in cancer cells from individuals with head and neck cancers compared to normal tissue from healthy volunteers.80 COX-2 fuels cancer growth by stimulating the formation of new blood vessels feeding the tumor.81,82 COX-2 increases cancer cell adhesion to the blood vessel walls,83 and also enhances the ability of cancer cells to metastasize. Experiments in mice revealed that colon cancer cells expressing high levels of COX-2 metastasized freely to the liver, while colon cancer cells expressing low levels of COX-2 did not metastasize to the liver.83

The adverse influence of COX-2 on the growth and progression of cancer was clearly revealed in a study published in the journal Clinical Cancer Research in 2004. Two hundred eighty-eight individuals undergoing surgery for colon cancer had their tumors examined for the presence of COX-2. The findings were alarming—when other factors were controlled for, the group whose cancers tested positive for the presence of COX-2 had a 311% greater risk of death compared to the group whose cancers did not express COX-2.84 A subsequent study in lung cancer patients found that those with high tumor levels of COX-2 had a median survival of only 15 months, whereas those with low tumor levels of COX-2 had a median survival of 40 months.85

Given these findings, researchers began investigating the anti-cancer effects of COX-2 inhibitor drugs. Although initially used for inflammatory conditions, such as arthritis, COX-2 inhibitor drugs have been shown to possess powerful anti-cancer activity. For example, 134 patients with advanced lung cancer were treated with chemotherapy alone or combined with Celebrex® (a COX-2 inhibitor). For those individuals with cancers expressing higher amounts of COX-2, treatment with Celebrex® dramatically prolonged survival.86 Treatment with Celebrex® also slowed cancer progression in men with recurrent prostate cancer.87

Perhaps the most impressive display of the anti-metastatic effects of COX-2 inhibitor drugs was presented at the annual conference of the American Society of Clinical Oncology in 2008. In this study, the incidence of bone metastases in breast cancer patients who had taken a COX-2 inhibitor for at least six months following the diagnosis of breast cancer was compared to the incidence of bone metastases in breast cancer patients who had not taken a COX-2 inhibitor. Remarkably, those who were treated with a COX-2 inhibitor were almost 80% less likely to develop bone metastases than those who were not treated with a COX-2 inhibitor drug.88

Non-steroidal anti-inflammatory drugs (NSAIDs), such as aspirin and ibuprofen, are COX inhibitors. The widespread use of NSAIDs for pain and arthritis has created an ideal environment in which to examine if these drugs can prevent cancer. Large-scale studies have documented a substantial reduction in cancer risk with the use of NSAIDs. A comprehensive review of the scientific literature (91 published studies) reported that the long-term use of NSAIDs (primarily aspirin) produced risk reductions of 63% for colon cancer, 39% for breast cancer, 36% for lung cancer, 39% for prostate cancer, 73% for esophageal cancer, 62% for stomach cancer, and 47% for ovarian cancer. “This review provides compelling… evidence that regular intake of NSAIDs that… block COX-2 protects against the development of many types of cancer,” the authors concluded.89

A number of nutritional and herbal supplements are known to inhibit COX-2. These include curcumin, resveratrol, vitamin E, soy isoflavones (genistein), green tea (EGCG), quercetin, fish oil, garlic, feverfew, and silymarin (milk thistle).58,90-97

Scientists at Memorial Sloan-Kettering Cancer Center in New York created an experimentally-induced increase in COX-2 activity in human breast cells, which was completely prevented by resveratrol. Resveratol blocked the production of COX-2 within the cell, as well as blocking COX-2 enzyme activity.98

Conclusion

A group of noted experts in the field of surgery-induced metastasis stated that cancer treatment “…necessitates the surgical excision of the primary tumor in order to relieve the patient of the major tumor burden, which is the main source of mutating and metastasizing cells. However, along with its obvious benefits, the surgical procedure has been suggested to involve serious hazards as it releases tumor cells into the circulation or lymphatics, promotes the secretion of angiogenic and growth factors, and induces suppression of CMI [immune function]. These consequences synergistically facilitate the establishment of new metastases and the development of preexisting micrometastases. As cancer-related death is most commonly the result of metastatic disease, it is crucial to minimize this facilitation.”55

Remarking further, they commented that “Taken together, it is evident that the perioperative period harbors many risks; however, it is also the ideal time for battling MRD [small numbers of cancer cells remaining after surgery] to reduce recurrence and future metastases.” Thus, these scientists believe “…it is essential to employ preventative interventions during this critical time.” Additionally, they urge that, “Ideally, each problematic aspect of surgery should be treated when oncological patients undergo resection [surgery] in order to minimize recurrence and metastatic spread.”55

Armed with the knowledge discussed in this article, the person with cancer can reap all the benefits that cancer surgery offers, while simultaneously avoiding the metastatic perils imposed by this procedure.

As this article was going to press, a dedicated team of clinical oncologists and researchers are preparing a meticulous report on the optimal doses of nutrients and drugs that a cancer patient should consider during the pre- and post-operative period. You can obtain a free copy of this report by logging on to our Cancer Surgery Special Report or calling 1-800-841-5433.

If you have any question on the scientific content of this article, please call a Life Extension® Health Advisor at 1-866-864-3027.

 

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How cancer cells start new tumor sites

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Posted 14 Mar 2012 — by James Street
Category CXCL12, metastases
Posted On: March 14, 2012 – 4:30pm

MAYWOOD, Il. — A Loyola University Chicago Stritch School of Medicine study has revealed details of the complex molecular process involving a protein that enables cancer cells to establish tumors in distant parts of the body.

The finding could lead the way to new drugs to prevent breast cancer and other cancers from spreading to new sites.

The study by Adriano Marchese, PhD and colleagues is published in the March 16 issue of the Journal of Biological Chemistry, and is now available online.

The study involves a molecule on the surface of cells called CXCR4. There is an abnormal abundance of this molecule in 23 types of cancer, including cancers of the breast, lung, pancreas and thyroid.

What usually kills patients is the spread of cancer from the primary site to other sites. A tumor cell breaks away from the primary site and circulates through the body. A molecule called CXCL12 acts like a beacon to CXCR4, signaling the cancer cell to land and start a new tumor.

The goal of the study was to better understand this complex signaling pathway. (A signaling pathway involves a group of molecules that work together in a cell. After the first molecule in the pathway receives a signal, it activates another molecule, and the process is repeated until the last molecule is activated.)

“We understand the final outcome of this signaling pathway,” Marchese said. “What we are trying to do now is understand the molecular details.”

In the study, Marchese and colleagues used a line of human cancer cells called HeLa. (The cell line is the subject of the bestselling book “The Immortal Life of Henrietta Lacks”.)

Using HeLa cancer cells, the researchers identified a molecule that is a critical link in the signaling pathway. Researchers hope to target this molecule, thereby disabling the signaling pathway and preventing the cancer cell from setting up shop in a new site, Marchese said.

The next step will be to develop a drug that blocks the target molecule. Researchers then would test the drug on an animal model. If the drug worked in animals, it later could be tested in a clinical trial of cancer patients, Marchese said.

“We are laying the groundwork for the development of new drugs to stop cancer from spreading,” Marchese said.

Marchese is an associate professor in the Department of Molecular Pharmacology and Therapeutics of Loyola University Chicago Stritch School of Medicine. His co-authors are Rohit Malik, PhD (first author), Unice J.K. Soh, PhD, and JoAnn Trejo, PhD.

 

Dual Inhibition of MET and VEGF Signaling With Cabozantinib Blocks Tumor Invasiveness and Metastasis

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Posted 28 Feb 2012 — by James Street
Category antiangiogenesis, cabozantinib, Cabozantinib, metastases, VGEF

press release

Feb. 24, 2012, 10:00 a.m. EST

– Preclinical data published in Cancer Discovery support clinical development program evaluating cabozantinib’s potential in multiple oncology indications

 

SOUTH SAN FRANCISCO, Calif., Feb 24, 2012 (BUSINESS WIRE) — Exelixis, Inc. EXEL -.00% today announced the company’s lead compound, cabozantinib, is highlighted in a new peer-reviewed publication demonstrating that simultaneous inhibition of MET and VEGF signaling reduces tumor invasiveness and metastasis in preclinical models of pancreatic cancer. The research, led by Dr. Donald M. McDonald at the University of California, San Francisco (UCSF), showed that selective inhibition of VEGF signaling with a neutralizing antibody against VEGF or with a small molecule kinase inhibitor resulted in more invasive and metastatic tumors than from placebo-treated mice. Importantly, this effect was accompanied by increased expression of MET. The researchers went on to show that treatment with cabozantinib (which targets both MET and VEGF signaling), or with a combination of selective inhibitors targeting both pathways, reduced these malignant processes. The researchers also reported that cabozantinib prolonged survival compared with all other treatment combinations examined.

The preclinical data will be published in the March 1, 2012 issue of Cancer Discovery and are also discussed in a press release issued by the American Association for Cancer Research, the journal’s publisher. Starting today, the article will be available at http://cancerdiscovery.aacrjournals.org . Researchers at Exelixis collaborated on the studies with UCSF.

“These data provide important insights into the potential clinical benefits of simultaneously inhibiting the MET and VEGF signaling pathways with cabozantinib, and add to the scientific rationale for our ongoing clinical investigation of the compound,” said Michael M. Morrissey, Ph.D., president and chief executive officer at Exelixis. “To date, cabozantinib has shown activity in 12 of 13 tumor types studied, including particularly encouraging interim results in castration-resistant prostate, medullary thyroid, renal, liver, ovarian, non-small cell lung, and breast cancers, as well as melanoma. These results suggest that, in many types of tumors, cabozantinib may have a potentially differentiated activity profile as compared to compounds that inhibit only VEGF or MET.”

In the research described in Cancer Discovery, tumor-bearing mice were treated with an anti-VEGF antibody or with sunitinib, which inhibits multiple tyrosine kinases including VEGF receptors. These treatments were tested alone or in combination with an inhibitor of MET. Separate groups of animals were treated with cabozantinib. Key findings include:

– Cabozantinib reduced tumor invasiveness compared with VEGF inhibition alone, through a mechanism consistent with MET inhibition.

– Liver metastases were completely absent in animals treated with cabozantinib.

– Overall survival was longest in cabozantinib-treated animals. All animals treated with cabozantinib survived until the end of the study, whereas most or all animals in all other treatment groups did not survive until the end of the study.

“Inhibition of VEGF signaling has become a mainstay of cancer therapy, and its ability to delay disease progression and prolong survival in certain cancers has been extensively documented. However, there is a growing body of evidence suggesting that VEGF inhibition on its own can lead to increased tumor aggressiveness in some preclinical models and in at least one human cancer,” said Donald M. McDonald, M.D., Ph.D., a member of the Helen Diller Comprehensive Cancer Center and the Cardiovascular Research Institute and professor of anatomy at UCSF. “These new preclinical findings suggest that upregulation of MET contributes to the evasive response of tumors to anti-VEGF therapy, and that simultaneous inhibition of MET and VEGF signaling can confer the benefits associated with VEGF inhibition while significantly reducing, and in some cases reversing, invasion and metastasis. Additional preclinical and clinical evaluation of combined MET and VEGF inhibition are clearly warranted.”

About Cabozantinib

Cabozantinib is a potent, dual inhibitor of MET and VEGFR2. Cabozantinib is an investigational agent that provides coordinated inhibition of metastasis and angiogenesis to kill tumor cells while blocking their escape pathways. The therapeutic role of cabozantinib is currently being investigated across several tumor types. MET is upregulated in many tumor types, thus facilitating tumor cell escape by promoting the formation of more aggressive phenotypes, resulting in metastasis. MET-driven metastasis may be further stimulated by hypoxic conditions in the tumor environment, which are often exacerbated by selective VEGF-pathway inhibitors. In preclinical studies, cabozantinib has shown powerful tumoricidal, antimetastatic and antiangiogenic effects, including:

– Extensive apoptosis of malignant cells

– Decreased tumor invasiveness and metastasis

– Decreased tumor and endothelial cell proliferation

– Blockade of metastatic bone lesion progression

– Disruption of tumor vasculature

About Exelixis

Exelixis, Inc. is a biotechnology company committed to developing small molecule therapies for the treatment of cancer. Exelixis is focusing its proprietary resources and development efforts exclusively on cabozantinib (XL184), its most advanced product candidate, in order to maximize the therapeutic and commercial potential of this compound. Exelixis believes cabozantinib has the potential to be a high-quality, broadly-active, differentiated pharmaceutical product that can make a meaningful difference in the lives of patients. Exelixis has also established a portfolio of other novel compounds that it believes have the potential to address serious unmet medical needs, many of which are being advanced by partners as part of collaborations. For more information, please visit the company’s web site at www.exelixis.com .

Forward-Looking Statements

This press release contains forward-looking statements, including, without limitation, statements related to: the continued development and clinical, therapeutic and commercial potential of, and opportunities for, cabozantinib; the belief that the referenced research and data support the cabozantinib clinical development program; the belief that interim results in various cancers are encouraging and suggest that cabozantinib may have a potentially differentiated activity profile compared to compounds that inhibit only VEGF or MET; the potential benefits of simultaneous inhibition of MET and VEGF; and the belief that additional preclinical and clinical evaluation of combined MET and VEGF inhibition are clearly warranted. Words such as “support,” “potential,” “ongoing,” “encouraging,” “suggest,” “may,” “can,” “warranted,” “believes,” and similar expressions are intended to identify forward-looking statements. These forward-looking statements are based upon Exelixis’ current plans, assumptions, beliefs and expectations. Forward-looking statements involve risks and uncertainties. Exelixis’ actual results and the timing of events could differ materially from those anticipated in such forward-looking statements as a result of these risks and uncertainties, which include, without limitation: risks related to the potential failure of cabozantinib to demonstrate safety and efficacy in clinical testing; Exelixis’ ability to conduct clinical trials of cabozantinib sufficient to achieve a positive completion; the availability of data at the referenced times; the sufficiency of Exelixis’ capital and other resources; the uncertain timing and level of expenses associated with the development of cabozantinib; the uncertainty of the FDA approval process; market competition; and changes in economic and business conditions. These and other risk factors are discussed under “Risk Factors” and elsewhere in Exelixis’ annual report on Form 10-K for the fiscal year ended December 30, 2011 and Exelixis’ other filings with the Securities and Exchange Commission. Exelixis expressly disclaims any duty, obligation or undertaking to release publicly any updates or revisions to any forward-looking statements contained herein to reflect any change in Exelixis’ expectations with regard thereto or any change in events, conditions or circumstances on which any such statements are based.

SOURCE: Exelixis, Inc.

        
        Exelixis, Inc. 
        Charles Butler, 650-837-7277 
        Vice President 
        Investor Relations and Corporate Communications 
        cbutler@exelixis.com

Cancer Therapy More Potent When It Hits Two Targets

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Posted 28 Feb 2012 — by James Street
Category antiangiogenesis, cabozantinib, crizotinib, MET, sunitinib, VGEF

ScienceDaily (Feb. 24, 2012) — Simultaneous targeting of two different molecules in cancer is an effective way to shrink tumors, block invasion, and stop metastasis, scientists at the University of California, San Francisco (UCSF) have found — work that may improve the effectiveness of combination treatments that include drugs like Avastin.

 

The two-target approach, tested in mice with a type of cancer known as neuroendocrine pancreatic tumors, may have broad application for treating a wide variety of cancers, the UCSF team said. The drugs used in the tests belong to classes of pharmaceuticals that are either on the market or under development in clinical trials.

Clinical trials also are already underway to gauge effectiveness of the approach in humans with prostate cancer, breast cancer, and other tumor types. The UCSF study, described in the journal Cancer Discovery this week, is the first to show how the drug combination works in the laboratory.

The results are promising, said Donald McDonald, MD, PhD, a member of the UCSF Helen Diller Comprehensive Cancer Center and the Cardiovascular Research Institute and professor of anatomy, who led the research.

In the study, treating mice with the dual-target approach turned aggressive tumors with invasive fingers penetrating surrounding tissues and many metastases into tiny balls with few or no metastases.

“It’s the combination of approaches — there’s a synergy between the two,” McDonald said. “You add two and two, and you get 10.”

How each target works

The two targets are both proteins that scientists have known for years are involved in cancer. Both play important roles in malignant tumors.

The first, called c-MET, is involved in two processes associated with the most deadly cancers. A clinical marker of cancer aggressiveness, c-MET drives tumor invasion into surrounding tissues. It is also involved in metastasis — the spread of cancer cells to other parts of the body where they can establish new tumors.

The second target is a protein known as vascular endothelial cell growth factor (VEGF). VEGF is a protein that promotes the growth of new blood vessels. Growing tumors hijack this process to expand their network of blood vessels to provide nutrients. Drugs blocking VEGF have been developed based on the simple assumption that tumors cannot grow if you choke off their blood supply.

Drugs that target these molecules are in development, and a few are already on the market. The U.S. Food and Drug Administration (FDA) approved the first of these in 2004 to treat metastatic colon cancer. That drug, called Avastin, is manufactured by the South San Francisco-based company Genentech. Avastin was approved for metastatic breast cancer in 2008 under the FDA’s accelerated approval program.

The FDA revoked approval of Avastin for breast cancer last year after further assessing the relative risks and benefits to women taking it. Blocking VEGF seemed to slow tumor growth for awhile, but the FDA determined that it did not significantly improve or extend the lives of most women taking it.

“It was not clear why some tumors responded and others did not. It was also unclear why some tumors would respond initially and then would stop responding,” said McDonald, who has studied blood vessels in tumors and the effect of cancer drugs for years in his UCSF laboratory.

Two years ago former UCSF professor Douglas Hanahan and colleagues found in laboratory experiments that Avastin-like drugs would shrink tumors but unexpectedly did something else as well. The drugs also morphed tumors from roundish blobs into highly irregular growths with tendrils that penetrated surrounding tissues and even spread to other organs — suggesting that the VEGF blockade could also make tumors more aggressive, invasive and metastatic.

McDonald’s group confirmed Hanahan’s findings and discovered that c-MET was involved. In their latest research, Barbara Sennino, PhD, with other investigators in his group set out to determine whether c-MET drove tumor aggressiveness during anti-VEGF therapy. What their paper shows is that blocking c-MET and VEGF together in mice is more powerful than blocking either alone because it not only slows tumor growth but also reduces invasion and metastasis.

They tested two inhibitors of VEGF — a neutralizing antibody and sunitinib — and three inhibitors of c-MET — crizotinib, PF-04217903, and cabozantinib (XL184). Unlike the other agents, cabozantinib simultaneously inhibits both c-MET and VEGF. Inhibition of c-MET and VEGF together with a drug combination or with cabozantinib had more profound effects on tumors than any of the agents that blocked only one of the targets.

These promising laboratory results still need more tests of safety and effectiveness in the clinic, McDonald said, and it may be a year or more before the drugs are routinely available to patients.

How Cancer Cells Change Once They Spread to Distant Organs

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Posted 28 Feb 2012 — by James Street
Category Breast Cancer, EMT, metastases, versican

ScienceDaily (Feb. 22, 2012) — Oncologists have known that in order for cancer cells to spread, they must transform themselves so they can detach from a tumor and spread to a distant organ. Now, scientists at Weill Cornell Medical College have revealed critical steps in what happens next — how these cells reverse the process, morphing back into classical cancer that can now grow into a new tumor.

Their findings, now published online and in a upcoming issue of Cancer Research and funded through a National Cancer Institute grant to the Cornell Center on the Microenvironment and Metastasis and the Neuberger Berman Foundation, show that a single protein, versican, is key to this process in breast cancer, the tumor they studied. When researchers stopped versican from functioning in mice, breast cancer could not “seed” themselves into the lungs and form secondary tumors.

“Our findings both help us understand how breast cancer metastasizes to the lungs and ways to possibly prevent that deadly spread,” says the study’s senior investigator, Dr. Vivek Mittal, an associate professor of cell and developmental biology in cardiothoracic surgery and director of the Neuberger Berman Lung Cancer Laboratory at Weill Cornell Medical College.

“These are exciting insights into a poorly investigated area,” Dr. Mittal says. “There are no clinically approved drugs now that can effectively target metastatic lesions, which is why more than 90 percent of human cancer-related deaths come from spread of the disease from a primary tumor.”

“The results of this study are a critical step in deconstructing the process of metastases — which is critical to curing our patients,” says co-author Dr. Linda T. Vahdat, professor of medicine, chief of the Solid Tumor Service and director of the Breast Cancer Research Program at Weill Cornell. “As a direct result of this study, we are working on ways to interrupt the process by which tumors co-opt the infrastructure in our bodies to grow and spread.”

This important study starts to unravel the mechanistic basis of cancer metastases, not only in breast cancer but possibly in other types of cancer, says Dr. Nasser Altorki, the David B. Skinner Professor of Thoracic Surgery at Weill Cornell Medical College and director of the division of thoracic surgery at NewYork-Presbyterian/Weill Cornell. “The need for a prepared and receptive soil may be required for cancer cell seeding regardless of the primary cancer’s site of origin.”

The Seed and the Soil Cancer researchers have believed that for a cancer to spread, its “seed” must find the right “soil” in a distant organ in order to thrive. And they have hypothesized that this seed is formed through a process known as epithelial-mesenchymal transition (EMT), in which cancer cells lose their sticky grip to other cells in a primary tumor and become more mobile, able to travel through the blood to a distant organ.

But what happens next is conjecture. Scientists have speculated that the cells undergo a reverse process, called mesenchymal-epithelial transition (MET), in which the cancer seeds morph back into epithelial cells that can make contact with tissue and integrate in the new organ. Little is known about MET compared to EMT.

In this study, Dr. Mittal, along with his colleagues at Weill Cornell, studied mouse models of spontaneous breast cancer development. They first discovered that primary breast tumors send a signal that forces bone-marrow-derived hematopoietic cells to move into the lungs of the mice. “This appears to be the soil the cancer seeds need,” says Dr. Mittal. The next question was obvious: What is it about the soil that helps the seed?

The team found that a subtype of these bone marrow cells expressed versican, which allowed the cancer cells, once they traveled to the lungs, to morph back into epithelial cells. “The primary tumor sets up the lung microenvironment to promote metastasis,” he says. “MET resulted not from properties within the cancer cell itself, but due to a unique crosstalk between the microenvironment and tumor cells in the lung.”

In their next experiment, the researchers blocked versican production by injecting small interfering RNAs (siRNAs) in the bone marrow that silenced the versican gene, which prevented MET and blocked tumor outgrowth in the lung.

Human Tumors Express Versican Next, they investigated human breast metastases to the lung, utilizing lung samples obtained from breast cancer patients contributed by researchers at the Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins University. “We found versican was highly expressed in those lung tumors, which matched what we found in our mice,” Dr. Mittal says. “This all made sense to us, because versican has been linked to cancer progression, although no one knew why.

“This is the first study demonstrating the significance of MET in the formation of macrometastases in distant organs,” Dr. Mittal says. “Given the findings, we now have a potential strategy to stop cancer spread before it starts, or to shut it down if it has already occurred.”

The study was funded by support from the Neuberger Berman Lung Cancer Laboratory, the Robert I. Goldman Foundation and National Cancer Institute support of the Cornell Center on the Microenvironment and Metastasis.

Study co-authors include, from Weill Cornell Medical College: Dingcheng Gao, Natasha Joshi, Hyejin Choi, Seongho Ryu, Mary Hahn, Raul Catena, Patrick Wagner, Linda T. Vahdat, Jeffrey L. Port, Brendon Stiles and Nasser K. Altorki; from Johns Hopkins University: Saraswati Sukumar, Helen Sadik and Pedram Argani; and Shahin Rafii from the Howard Hughes Medical Institute and Weill Cornell Medical College.

Scientists illuminate cancer cells’ survival strategy

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Posted 31 Jan 2012 — by James Street
Category CDCP1, metastases, Molecular

January 26, 2012

A team led by scientists at The Scripps Research Institute has discovered key elements of a strategy commonly used by tumor cells to survive when they spread to distant organs. The finding could lead to drugs that could inhibit this metastasis in patients with tumors.

A cell that breaks away from the primary and finds itself in the alien environment of the or a new organ, normally is destroyed by a process known as apoptosis. But that express high levels of a certain surface are protected from apoptosis, greatly enhancing their ability to colonize distant organs. How this protein blocks apoptosis and promotes has been a mystery—until now.

“What we found in this study is that it’s not the increased expression of the protein per se that protects a tumor cell, but, rather, the cleavage of this protein by proteolytic enzymes,” said Scripps Research Professor James P. Quigley. “This cleavage triggers a signaling cascade in the tumor cell that blocks apoptosis.” Quigley is the principal investigator for the study, which was recently published online before print by the journal Oncogene.

“We think that a reasonable strategy for inhibiting metastasis would be to try to prevent the cleavage of this using antibodies or small-molecule drugs that bind to the cleavage site of the protein,” said Elena I. Deryugina, a staff scientist in Quigley’s laboratory and corresponding author of the manuscript.

A Protein Linked to Poor Outcomes

The cell-surface protein at the center of this research is known as CUB Domain Containing Protein 1 (CDCP1). In 2003, a postdoctoral fellow in Quigley’s laboratory, John D. Hooper, discovered and co-named CDCP1 as a “Subtractive Immunization Metastasis Antigen,” also finding that it is highly expressed on the surfaces of metastasis-prone human tumor cells.

Quigley’s laboratory and others soon found additional evidence that CDCP1 plays a major role in enabling metastasis. Clinical studies reported CDCP1 on multiple tumor types and linked its presence to worse outcomes for patients. Deryugina and Quigley reported in 2009 that CDCP1, when expressed in tumor-like cells, strongly promotes their ability to colonize new tissues and that unique monoclonal antibodies to CDCP1, generated in Quigley’s lab, significantly block CDCP1-induced tumor colonization. Hooper, who now leads a laboratory at the Mater Medical Research Institute in Brisbane, Australia, reported in a cell culture study in 2010 that most of the CDCP1 protein on the cell membrane could be cleaved by serine proteases. This cleavage event seems to lead to the biochemical activation of the internal fragment of CDCP1 by a process called tyrosine phosphorylation, in this case involving the cancer-linked protein Src.

MIT Researchers Target Cancer’s Most Deadly Phase

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Posted 25 Dec 2011 — by James Street
Category Lung Metastases, Metastases, metastases
Author: Marcia Stone : Posted to Decoded Science on December 24, 2011 at 2:12 pm
Invasive human breast cancer: Image courtesy of Robert Weinberg

If malignant cells could be kept from wandering about the body and colonizing new sites, the number of cancer deaths would be cut by about 90%. However, it’s become apparent in recent years that metastasis isn’t a simple, random process; it’s a well-orchestrated sequence of events most of which are largely unknown.

In fact, “[metastasis] remains the most poorly understood component of cancer pathogenesis,” says Robert A. Weinberg, PhD, Professor of Biology at the Massachusets Institute of Technology (MIT) in Cambridge. Professor Weinberg helped identify ras, the first human oncogene, in the 1970s and a few years later the first known tumor suppressor gene, Rb.  Most recently, Weinberg’s team at the MIT Whitehead Institute for Biomedical Research created the first genetically-defined human cancer cells.

Robert A. Weinberg Discusses his Latest Research with Colleagues at the SKI in December

Understanding how metastasis works has great clinical potential and this is why, Weinberg told cancer experts at the Sloan-Kettering Institute’s President’s Research Seminar, held at the Rockefeller Research Laboratories (RRL) in New York City on December 14th, the scientists in his laboratory are vigorously investigating this “most enigmatic” aspect of cancer.

For starters, the Weinberg and colleagues have organized the complex metastatic cascade into two major parts: first, the physical translocation of a cancer cell from its primary tumor to a distant site and second, colonization.  An understanding of the first step, physical dissemination, is in sight he says. However, colonization is far more complicated and may require several more years of research before the traits a cancer cell needs to implant and grow in alien soil are fully understood.

Nonetheless, knowing how a cancer cell escapes the confines of a tumor and explores adjacent environments is expected to prove important for preventing metastasis in people with early cancer lesions. Designing effective therapies for patients with already-established disease will have to wait.

“Tumor-Initiating” Cancer Stem Cells (CSCs) 

“The discovery of CSCs has forced  major rethinking of tumor biology,” says Weinberg, adding that a variety of cancer-associated traits once ascribed to tumor cell populations as a whole are now known to be associated with one or another subpopulations of CSCs.  CSCs exist side-by-side with normal self-renewing stem cells (SCs); but unlike SCs, CSCs have greatly enhanced tumor-initiating potential thus the ability to seed new cancers.

One critical role of CSCs in metastasis is obvious, Weinberg notes; they act as founder cells, spawning vast numbers of descendants. Indeed, the very traits that define CSCs – self-renewal and tumor initiating ability – also define successful metastasis. However CSCs have other less well-recognized attributes necessary for metastasis: motility, invasiveness, and a heightened resistance to apoptosis. This implies that a multifaceted biological program exists within a primary tumor empowering some cancer cells to escape and start colonies elsewhere. It also suggests that cancer is a systemic disease long before any of the malignant cells begin migrating.

The Epithelial-to-Mesenchymal Transition

Embryonic tissue differentiates with a program known as the EMT, shorthand for “epithelial-to-mesenchymal transition,” which is also activated during cancer invasion and metastasis.  “The EMT enables both normal and neoplastic epithelial cells to acquire mesenchymal cells attributes such as motility, invasiveness, and a resistance to apoptosis,” Weinberg says. Carcinoma cells with mesenchymal attributes can not only physically disseminate, they can self-renew which enables them to seed new environments. Long-term exposure to stroma-associated signals also helps keep cells in the mesenchymal/stem-cell state in a self-sustaining, stable fashion.  Additionally, their resistance to programmed cell death or apoptosis is, “surely critical to the ability of the migrating cells to survive the rigors of the voyage” from primary tumors to distant sites, he adds.

Moreover, primary carcinomas, the Weinberg team’s target cancers, release signals that recruit inflammatory cells to the tumor. This both helps assemble a highly functional, tumor-supporting environment, or stroma, and keeps some of the cells in a biologically-abnormal activated state.  However, while conceptually appealing, Weinberg cautions that the role of EMT in metastasis remains unproven.

Cancer Colonization 

Pelvis with bone metastasis: Image courtesy of Diagnostic pathology

Although EMT programs seem critical for the physical dissemination of carcinoma cells, they don’t appear capable of initiating and sustaining colonization.  Colonization, Weinberg emphasizes, seems to entail a far more complex set of phenomena, and have a relatively small number of unifying general principles. The tissue microenvironment of a primary tumor is likely to differ markedly from that of a secondary site which requires the wandering cancer cell to make substantial adaptive changes in order to survive and multiply. These changes appear to be dictated by both the microenvironment of the primary tumor as well as that of the landing site.

In general, says Weinberg, colonization is an extremely inefficient process, and most cancer cells that successfully translocate from a primary to a secondary site don’t survive more than 24 hours in their new home. This is good news because the outcome of successful colonization is a rapidly expanding macrometastasis that disseminates a shower of secondary metastases. Moreover, cancer cells being dispatched from the successful new colony are likely to be invested with the kinds of genetic programs that make it easier for them to migrate and colonize a variety of tissues.  These cells are so much more fit than their ancestors that the “throngs of secondary metastases derived from the initial metastatic shower soon eclipse the initiating metastasis that spawned them,” Weinberg stresses.

Sources:

Robert A. Weinberg, Ph.D. 2011 Calloway Lecture: EMT, Cancer Stem Cells and Malignant Progression. December 14, 2011.

Chaffer, C. L., Weinberg, R. A. A Perspective on Cancer Cell Metastasis. Science: 331:1559-1564, 25 March 2011. Accessed December 24, 2011.

Mani, S. A., Guo, W., Liao Mai-Jing, et al. The Epithelial-Mesenchymal Transition Generates Cells with Properties of Stem Cells. Cell: 133, 704-715, 16 May 2008.

Mukherjee, S. The Emperor of All Maladies: A Biography of Cancer. New York City. Scribner. (2010). ISBN 978-1-4391-0795-9.

 

N-acetyl-cysteine (NAC)–is an anticarcinogenic and antimutagenic agent

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Posted 21 Nov 2011 — by James Street
Category Antiagiogenesis, Metastases, metastases, N-acetylcisteine

N-acetyl-cysteine (NAC)–is an anticarcinogenic and antimutagenic agent; it inhibits IL-6 as well as invasion and metastasis of malignant cells
N-acetyl-cysteine (NAC) is the acetylated precursor of the amino acids L-cysteine and reduced glutathione. Historically, it is used as a mucolytic agent in respiratory illnesses as well as an antidote for acetaminophen hepatotoxicity, but more recently its credits have grown. Animal and human studies have shown it to be a powerful antioxidant and a potential therapeutic agent in the treatment of cancer (Bongers et al. 1995; van Zandwijk 1995).

The biological value of NAC is attributed to its sulfhydryl group, while its acetyl-substituted amino group offers protection against oxidative and metabolic processes (Bonanomi et al. 1980; Sjodin et al. 1989). In vitro studies showed NAC to be directly antimutagenic and anticarcinogenic; in vivo, NAC inhibited mutagenicity of a number of mutagenic materials (De Flora et al. 1986, 1992).

NAC has both chemopreventive and therapeutic potential in malignancies arising in the lung, skin, breast, liver, head, and neck (van Zandwijk 1995; Izzotti 1998). NAC is effective in inhibiting tumor cell growth in melanoma, prostate cells, and astrocytoma cell lines (the latter is a primary tumor in the brain) (Albini et al. 1995; Arora-Kuruganti et al. 1999; Chiao et al. 2000). Neovascularization (new blood vessel growth) is crucial for tumor mass expansion and metastasis. NAC inhibited invasion and metastasis of malignant cells by up to 80% by preventing angiogenesis (De Flora et al. 1996).

A number of cancers express IL-6 and other potentially dangerous cytokines. NAC inhibited (in a dose-dependent manner) the synthesis of IL-6 by alveolar macrophage (Munoz et al. 1996; Gosset et al. 1999).

Peak plasma levels of NAC occur approximately 1 hour after an oral dose; 12 hours after dosing, it is undetectable. Despite a relatively low bioavailability (4-10%), research has shown NAC to be clinically effective (Borgstrom et al. 1986). A suggested NAC therapeutic dosage is usually in the range of 600 mg per day.

Alcohol may thwart breast cancer’s spread

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Posted 19 Nov 2011 — by James Street
Category Alcohol, Breast Cancer, Lung Metastases, metastases
By Rachael Rettner

updated 11/17/2011 8:48:58 PM ET

Although drinking alcohol appears to increase the risk of developing breast cancer, drinking may be beneficial for those who already have the disease, a new study of mice suggests.

Of the mice in the study that had breast cancer, those that were given moderate to high levels of alcohol had fewer instances of cancer spreading to other parts of the body than alcohol-free mice did.

The study is one of the first to look at the effect of drinking on cancer metastasis, said study researcher Gary Meadows, a professor of pharmacy at Washington State University.

However, Meadows said it’s important to conduct further studies so that doctors can best advise breast cancer patients on the risks and benefits of consuming alcohol after diagnosis. Whether humans would experience the same effect is unknown, and in any case, it could be impractical as a treatment: The mice that fared best in the study drank so much alcohol that if they were people, they probably would be considered alcoholics, Meadows said.

The findings were presented Nov. 3 at the American Institute for Cancer’s annual meeting in Washington, D.C.

For the study, tumors were injected into mice’s mammary glands (where breast cancer usually originates), and the mice were then divided into four groups. Three groups drank water mixed with differing levels of alcohol (low, moderate or high), and the fourth group drank only water.

After four weeks, the researchers checked the mice to see if the cancer had spread to their lungs.

Mice who drank water spiked with a high dose of alcohol were 60 percent less likely to develop metastases in their lungs than those that drank plain water.

Some protection against metastases was seen in mice in the moderate-dose group, but none was seen in the low-dose group.

The researchers aren’t sure how alcohol, which is carcinogenic, may act to suppress breast cancer’s spread. The study showed alcohol did not affect the growth of tumors in the breast. So it may have affected the spread of the tumor in a different way, such as allowing the immune system to better attack the cancer at other sites in the body.

Although we don’t know what effect alcohol has on metastases in people, the study “provides some clues as to what could potentially occur,” said Somdat Mahabir, a nutritional epidemiologist at the National Institutes of Health, who was not involved with the study.

Previous studies showed alcohol can reduce metastases in animals with certain types of skin cancer.

Although alcohol has toxic effects, it could still theoretically be a treatment.

“I’m not opposed to anything that may have a therapeutic effect,” Mahabir said. “But we need to weigh the risks versus the benefits.”

Studies that ask questions about alcohol consumption before and after cancer diagnosis, and that follow patients over time, could provide a better idea of how alcohol affects cancer metastases in people, Mahabir said.

Pass it on:High doses of alcohol suppress the spread of breast cancer tumors in mice.

 

Tyrosine Isomers Mediate the Classical Phenomenon of Concomitant Tumor Resistance

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Posted 19 Nov 2011 — by James Street
Category Metastases, metastases, Tyrosine
  1. Raúl A. Ruggiero1,
  2. Juan Bruzzo1,
  3. Paula Chiarella1,
  4. Pedro di Gianni1,
  5. Martín A. Isturiz1,
  6. Susana Linskens2,
  7. Norma Speziale2,
  8. Roberto P. Meiss3,
  9. Oscar D. Bustuoabad1, and
  10. Christiane D. Pasqualini1

+ Author Affiliations


  1. Authors’ Affiliations:1División Medicina Experimental, Academia Nacional de Medicina; 2Facultad de Farmacia y Bioquímica, UBA; and 3Instituto de Estudios Oncológicos, Academia Nacional de Medicina, Buenos Aires, Argentina
  1. Corresponding Author:
    Raúl A. Ruggiero, División Medicina Experimental, Academia Nacional de Medicina, Pacheco de Melo 3081 (1425), Buenos Aires, Argentina. Phone: 54-11-4805-3411; Fax: 54-11-4803-9475; E-mail: ruloruggiero@yahoo.com.ar

Abstract

Concomitant tumor resistance (CR) is a phenomenon originally described in 1906 in which a tumor-bearing host is resistant to the growth of secondary tumor implants and metastasis. Although recent studies have indicated that T-cell–dependent processes mediate CR in hosts bearing immunogenic small tumors, manifestations of CR induced by immunogenic and nonimmunogenic large tumors have been associated with an elusive serum factor. In this study, we identify this serum factor as tyrosine in its meta and ortho isoforms. In three different murine models of cancer that generate CR, both meta-tyrosine and ortho-tyrosine inhibited tumor growth. In addition, we showed that both isoforms of tyrosine blocked metastasis in a fourth model that does not generate CR but is sensitive to CR induced by other tumors. Mechanistic studies showed that the antitumor effects of the tyrosine isoforms were mediated, in part, by early inhibition of mitogen-activated protein/extracellular signal-regulated kinase pathway and inactivation of STAT3, potentially driving tumor cells into a state of dormancy. By revealing a molecular basis for the classical phenomenon of CR, our findings may stimulate new generalized approaches to limit the development of metastases that arise after resection of primary tumors, an issue of pivotal importance to oncologists and their patients. Cancer Res; 71(22); 7113–24. ©2011 AACR.

Footnotes

  • Note: Supplementary data for this article are available at Cancer Research Online (http://cancerres.aacrjournals.org/).

  • R.A. Ruggiero, M.A. Isturiz, N. Speziale, O.D. Bustuoabad, and C.D. Pasqualini are members of Research Career of CONICET; Juan Bruzzo and Paula Chiarella are Fellows of CONICET.

  • Received February 17, 2011.
  • Revision received August 16, 2011.
  • Accepted September 2, 2011.