Bacteria May be Inactivating Common Cancer Drugs

The Bacteria Within

A new study is looking at how anti-cancer drugs may be inactivated by bacteria contained within certain cancerous tumors.1 The research is currently specific to colon cancer and pancreatic tumors, in which the research has shown bacteria can exist which actually degrades certain chemotherapy drugs – gemcitabine is cited in the study. The theory of using antibiotic therapy in conjunction with chemotherapy to enhance the treatment is being tested.

Gammaproteobacteria

Gammaproteobacteria has been found to exist in both colon cancer and pancreatic cancer by the research team. Gammaproteobacteria has the ability to metabolize the chemotherapeutic agent, gemcitabine into its inactive form. This metabolism is made possible by expression of a long isoform of a bacterial enzyme, cytidine deaminase (CDDL). Gemcitabine is a commonly used drug for pancreatic ductal adenocarcinoma (PDAC).

Bacteria Housed Within Tumors

The bacteria was found to live within the tumors, and even in the tumor cells themselves. The research team underwent methods to prove that they were actually living in the cells, and that they weren’t the result of laboratory contamination, which is a common concern with laboratory cell studies. They then looked at the effects the bacteria might have on chemotherapy agents. They found that some of the bacteria did keep the drug from working, that they were indeed metabolizing the gemcitabine. But others weren’t. As it turned out there is genetic coding for a long form and a short form of the CDD enzyme. Only the long form, CDDL, was found to inactivate gemcitabine.

Pancreatic Tumors Treated with Gemcitabine and Ciprofloxacin

The team decided to treat the pancreatic tumors with a combination therapy which included gemcitabine and an antibiotic, ciprofloxacin. This group did respond to the chemotherapy drug. The main question the research is asking now is what other cancers may be harboring bacteria, and what other chemotherapy drugs may be inactivated as a result, as well as what is the best antibiotic combination therapy to approach them with.

Source:

  1. Geller LT, Barzily-rokni M, Danino T, et al. Potential role of intratumor bacteria in mediating tumor resistance to the chemotherapeutic drug gemcitabine. Science. 2017;357(6356):1156-1160.
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Node Smith, ND, is a naturopathic physician in Portland, OR and associate editor for NDNR. He has been instrumental in maintaining a firm connection to the philosophy and heritage of naturopathic medicine among the next generation of docs. He helped found the first multi-generational experiential retreat, which brings elders, alumni, and students together for a weekend camp-out where naturopathic medicine and medical philosophy are experienced in nature. Four years ago he helped found the non-profit, Association for Naturopathic ReVitalization (ANR), for which he serves as the board chairman. ANR has a mission to inspire health practitioners to embody the naturopathic principles through experiential education. Node also has a firm belief that the next era of naturopathic medicine will see a resurgence of in-patient facilities which use fasting, earthing, hydrotherapy and homeopathy to bring people back from chronic diseases of modern living; he is involved in numerous conversations and projects to bring about this vision.

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