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Fighting Cancer With Scorpions?
Fox News
by Chris Kilham

In the fight against cancer, scientists and medical researchers around the world are developing new medicines from seemingly unlikely natural substances. Recent reported developments involve the use of a bacteria found in soil, a poison from a highly toxic scorpion, and the virus that causes herpes. All three demonstrate novel properties that may save lives in cases of otherwise hard to treat killer cancers.

The use of bacteria for health and therapeutic purposes is in fact quite common. Various beneficial bacteria within the human digestive tract support digestion and elimination, help to detoxify the body, reduce the risk of some types of disease, and help to maintain overall health. These bacteria are widely available in supplements, and in various “live, active” yogurts. But ever since Edward Jenner developed the first vaccine (for cow pox) in 1796, bacteria have also played central roles in the development of vaccines against several diseases, including against tuberculosis, and even for plague, as in the case of Yersinia pestis. A team from North Carolina State University is developing an oral vaccine against deadly Anthrax poisoning, using Lactobacillus acidophilus, a common beneficial bacteria used to culture yogurt.

Recent findings from Britain’s University of Nottingham show another ingenious use for bacteria, in the treatment of cancers. A team of scientists led by Professor Nigel Minton has reported that the bacteria Clostridium sporogenes a species widespread in nature, can be used as a vehicle to deliver anovel enzyme that activates a cancer drug within tumors in the brain. The Clostridium sporogenes bacteria is anaerobic, which means that it does not require oxygen to live and multiply. This bacteria is associated with a foul odor, and typically occurrs in gangrenous infections. Spores of Clostridium sporogenes can grow within tumors where there is no oxygen, including solid tumors, of the breast, brain and prostate, though not tumors in other tissues of the body where oxygen is present.

In the UK and Netherlands scientists have genetically engineered an enzyme into the Clostridium sporogenes bacteria to deliver a cancer drug into anaerobic brain tumors. If their work continues to demonstrate success, this bacteria will be used to transport anti-cancer agents into previously inaccessible forms of cancer. The findings of this group will be presented at the annual meeting of the Society of Microbiology at the UK’s University of York. Key to the findings of the group is that the use of this bacteria as a drug delivery system appears to leave healthy tissue surrounding tumors unharmed, in contrast to both chemotherapy and radiation treatment. This in and of itself is a milestone in cancer therapy.

Meanwhile, according to findings reported in the American Chemical Society (ACS), a compound called chlorotoxin from the highly poisonous venom of the deathstalker scorpion Leiurus quinquestriatus may also help to deliver anti-cancer genes to glioma, the most common and serious form of brain cancer. According the work of Dr Miqin Zhang and his colleagues at the University of Washington, chlorotoxin from deathstalker scorpion venom allows therapeutic genes to reach more brain cancer cells than other approaches.

This is not the only toxin derived from wild creatures that demonstrates serious medicinal value. In China, neurologists successfully use toxins from centipedes to halt the progress of Parkinson’s disease. At the National Institutes of Health, investigators are studying toxins derived from cone snails from the sea, for their possible use in the treatment of neurodegenerative disorders including Alzheimer’s and ALS, or Lou Gehrig’s disease.

In the ACS article, the scientists describe a new approach that could solve the problem of delivering specially engineered anti-cancer genes to invasive, hard-to-reach brain cancer. Chlorotoxin from scorpion venom, combined with nanoparticles of iron oxide, can induce almost double the transport of anti-cancer genes into brain cancer cells as nanoparticles that do not contain the scorpion toxin. The deathstalker scorpion, also known as the Palestine yellow scorpion, is found from North Africa to the Middle East, and delivers a highly painful toxic sting that can be fatal. Nonetheless, its venom shows significant medicinal promise. The researchers conclude that “These results indicate that this targeted gene delivery system may potentially improve treatment outcome of gene therapy for glioma and other deadly cancers.” Since it is very difficult to target brain cancers specifically, the work of this team has the potential to revolutionize the treatment of otherwise deadly cancer.

Not to leave viruses out of the mix, doctors based at the Institute of Cancer Research in London report that they have used a genetically engineered herpes virus called HSV to successfully treat patients with head and neck cancers. The virus apparently works by penetrating cancer cells, killing them from the inside, and enhancing the patient's immune system. A trial of 17 patients at London’s Royal Marsden Hospital found that use of the specially engineered virus in conjunction with chemotherapy and radiotherapy helped to successfully kill such tumors in most patients. The group showed an 83 percent success rate two years after this treatment, compared with an average of 35 to 55 percent improvements with current conventional therapies.

In the new therapy, the herpes virus is genetically manipulated to grow inside tumor cells without infecting normal healthy cells. Further trials are planned for later in the year. Head and neck cancer, which includes cancer of the mouth, tongue and throat, account for between 3 to 5 percent of cancers in the U.S. The UK work was conducted by Dr. Kevin Harrington and his team at the Institute of Cancer Research in London.

Viruses have long been used to develop vaccines, using inactive viruses to develop protection against serious diseases. Virus-derived vaccines include those for smallpox, rabies, and polio. The use of viruses for the treatment of cancers is comparatively new, but shows great promise in improving cancer survival.

Nature provides many thousands of known medicines, including those from plants, animals, insects and microorganisms. Natural substances play key roles as chemotherapeutic agents, and as novel transport systems. As current work demonstrates, this field is yielding breakthroughs in the treatment of deadly cancers.

September 2011