A bacterium discovered in a cave may help scientists to develop new treatments for cancer.

The researchers, from Grand Valley State University, discovered the bug in Mammoth Cave in Kentucky.

The substance produced by this bacterium may be a new tool in the fight against cancer

Dr Ryan Frisch

It produces a substance that appears to inhibit the activity of a protein involved in the formation of new blood vessels, a process known as angiogenesis.

This is significant because, when cancer cells begin to form tumours, one of the requirements is the formation of new blood vessels to provide the tumour with oxygen and nutrients.

Laboratory tests on yeast cultures have yielded promising results.

Researcher Dr Ryan Frisch said. "One of the strategies in the fight against cancer is to discover drugs that are anti-angiogenic because, if blood vessels are not produced, the tumour does not grow and prosper.

"These experiments indicate that the substance produced by this bacterium may be a new tool in the fight against cancer."

Natural solutions

Scientists are increasingly turning to nature to develop new drugs for diseases such as cancer.

Natural products are much more diverse and structurally complex than synthetic compounds created by medicinal chemists.

Vinblastine and vincristine, isolated from the rosey periwinkle, have contributed to the successful treatment of childhood leukaemias, testicular cancer and Hodgkin's lymphoma since their introduction into cancer clinics in the late 1960s.

Taxol, used to treat breast and ovarian cancer, comes from the bark of the Pacific yew tree. Some key chemotherapy drugs, like bleomycin and doxorubicin, come from micro organisms.

And marine sources, like seaweeds, sponges and molluscs, are now a major focus of research in the hunt for new and better anticancer agents.

Similar findings

Nicola Hawe, science information for the Cancer Research UK, said: "Some angiogenesis inhibitors have come from natural products, including a drug called combretastatin A-4, isolated from the African bush willow.

"A number of anti-angiogenic drugs are currently in clinical trials involving patients with a wide range of cancers and it seems they will play an important role in cancer treatment.

"Initial results suggest they may be most beneficial when used in combination with conventional treatments like chemotherapy and radiotherapy.

"The compound found by the US researchers may turn out to be a lead for further anti-angiogenic drug development.

"Even with the advent of advanced technologies that allow chemists to design powerful synthetic anticancer molecules, they still often rely on the natural world to provide them with lead compounds."

The new bacterium is a member of the Pseudomonas Tolaasi subgroup of organisms.

The research was highlighted at a meeting of the American Society for Microbiology.