Archive for the ‘Bacteria’ Category

‘Trojan horse’ bacteria delivering tumor-killing blow comes from the soil

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Posted 04 Sep 2011 — by James Street
Category Bacteria, Clinical Trials, Complementary and Alternative Medicine, Drugs, experimental treatments, Hypoxia

Posted Sun, 04 Sep 2011 23:01:00 GMT by

Cancerous tumors may just have met their nemesis, according to scientists speaking at the autumn conference of the Society for General Microbiology, which kicks off the UK tomorrow. But the fatal blow being delivered to dangerous tumors comes from an unlikely source – soil-dwelling bacteria, that have a special attraction for conditions found at a tumor’s heart. This new therapy - the result of collaboration between the UK-based University of Nottingham, and University of Maastricht, in Holland – should enter clinical trials within 2 years.

The bacterium being harnessed is widespread, harmless and has been on the planet for billions of years. Team leader, Professor Nigel Minton, described them: “Clostridia are an ancient group of bacteria that evolved on the planet before it had an oxygen-rich atmosphere and so they thrive in low oxygen conditions. When Clostridia spores are injected into a cancer patient, they will only grow in oxygen-depleted environments, i.e. the center of solid tumors.” This makes them ideal ‘trojan horse’ candidates for targeting tumors.

“This is a totally natural phenomenon, which requires no fundamental alterations and is exquisitely specific. We can exploit this specificity to kill tumor cells but leave healthy tissue unscathed,” said Professor Minton.  The trick to turning this selectivity into a tumor-killing therapy lies with giving the bacteria a weapon of attack. That comes from the insertion of an enzyme-producing gene into the Clostridia’s DNA. It is tuned-in to unlock a cancer-destroying ‘pro-drug’.

The pro-drug is separately administered, and remains harmless until the enzyme and pro-drug are combined. When this happens, the enzyme activates the drug, which takes on its destructive form – killing the cells around it. As only the cancerous cells have the Clostridia bacteria present, this is an elegant solution for removing tumors.

No need for the scalpel?

The approach is one that others have sought to make work, but the difficulty has been getting the bacteria to produce the right enzyme in the needed quantities. The team presenting their paper at this week’s conference feel that they have cracked this. Their bacterial strain has a gene that produces the enzyme more efficiently, and in larger amounts, than has previously been achieved.

The clinical trials are likely to be scheduled in the next 18 months. “We anticipate that the strain we have developed will be used in a clinical trial in 2013 led by Jan Theys and Philippe Lambin at the University of Maastricht in The Netherlands. A successful outcome could lead to its adoption as a front-line therapy for treating solid tumors.”

If all pans out as predicted, then we could see the therapy become a major new tool in defeating cancer. “This therapy will kill all types of tumor cell. The treatment is superior to a surgical procedure, especially for patients at high risk or with difficult tumor locations,” said Professor Minton. “If the approach is successfully combined with more traditional approaches this could increase our chance of winning the battle against cancerous tumors.”

Researchers investigate modifying a harmless type of the bacterium, Salmonella typhimurium, to kill bone cancer cells

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Posted 23 Nov 2010 — by James Street
Category Bacteria, Bacteria

Children and young people who are diagnosed with bone cancer could benefit from better treatment in the future thanks to new research at The University of Nottingham.

The Bone Cancer Research Trust launches Bone Cancer Awareness Week today and has funded a new project at the University which is testing a theory that ‘friendly bacteria’ can be used to kill bone cancer cells.

Researchers at the School of Clinical Sciences’ Division of Pre-Clinical Oncology are investigating whether modifying a harmless type of the bacterium, Salmonella typhimurium, can produce molecules which kill cancer cells in osteosarcoma, a primary bone cancer. The scientists are using a clinically safe form of the bacterium which has been found to localise to tumour tissue rather than healthy tissue.

Leading the research, Dr Teresa Coughlan, said: “Developing a treatment that effectively targets cancer cells, but doesn’t damage healthy cells is the Holy Grail for bone cancer treatment. We are excited by this project as potentially it could result in a new treatment for osteosarcoma, which typically has a poor prognosis.”

Osteosarcoma (OS) is the most common type of primary bone cancer and although rare, can be particularly distressing because it affects mostly children and adolescents. Cases tend to have a poor outlook because the cancer often does not respond well to the treatments currently available. There have been few new treatments for OS in the past 20 years and more research and techniques to fight it are urgently needed as more than 2,000 children and young people are diagnosed with the disease every year in the UK.

A main challenge in developing better treatments for bone cancer is finding a much more effective way of targeting anti-cancer drugs at the tumour. Many drugs are given by intravenous injection and use the body’s venous system to reach their target, but tumours in bone tend to have a low blood supply.

Dr Coughlan’s aim is to modify the Salmonella bacteria to act as a vehicle for cancer-killing agents. It’s believed special molecules, called RNA interference molecules, when produced in the bacteria will be more effectively released into malignant cells destroying the levels of cancer-causing molecules there.

It’s hoped this research will eventually lead to a treatment for bone cancer that is better targeted at tumours and doesn’t affect normal, healthy tissue.

Source: The University of Nottingham.

Source: http://www.news-medical.net/news/20101012/Researchers-investigate-friendly-bacteria-to-kill-bone-cancer-cells.aspx