Cancer Cleared by Bacteria


Frequently, the rate at which a cancer grows out-strips its blood supply, resulting in the creation of pockets of poorly oxygenated tissue. This dead or dying tissue is resistant to standard chemotherapies and ionizing radiation, whose actions depend on an adequate blood and oxygen supply, respectively. Now, researchers at Johns Hopkins Oncology Center and the Howard Huges Medical Institute (Baltimore, MD) suggest that anaerobic bacteria could be used to destroy this recalcitrant tissue. Bert Vogelstein and colleagues screened 26 strains of anaerobic bacterial variants, injecting spores into mice bearing colon cancers and melanomas (Proc. Natl, Acad. Sci. USA, 27 November 2001, early edition; PMID 11724950). Two of the strains - Clostridium novyi and Clostridium sordellii - germinated, spreading extensively through a vascular regions of the tumors. A variant devoid of endotoxin-producing genes, C. novyi - NT, was generated to circumvent the fatal release of endotoxin. A combination of chemotherapies and C. novyi-NT rapidly eliminated the tumours in half of the mice. The researchers say that they must next determine which types of cancers will best benefit from combination therapy: for example, small metastatic tumors lacking necrotic centers may not respond to the combination therapy.


AIBA, (Nature Biotechnology, January 2002)