Developing cancer drugs is challenging. Often, scientists will find a drug that kills cancer cells in a petri dish but fails to act on an actual tumor. Ravid Straussman from the Weizmann Institute of Science and Todd Golub from Harvard Medical School think that in situ, bacteria can protect cancer cells from drugs.

To test their theory, Staussman and Golub mixed some healthy skin cells with cells from a pancreatic cancer patient. The research team then removed the healthy skin cells from the mixture, but left the solution housing the original mixture untouched. When treated with a test drug, the cancer cells still survived. After filtering the original solution, and removing compounds consistent with bacteria, the cancer cells were finally able to be killed.

Further study revealed that bacterial cells are able to protect cancer by producing an enzyme called cytidine deaminase, or CDD enzyme. CDD enzyme is produced by many bacterial cells in the human body, and is capable of destroying drugs that attempt to kill cancer cells.

Our expert, Silvia Escudero, who studies Pediatric Oncology at the Dana Farber Cancer Institute, states that the influence of the microbiome, or the billions of non-harmful bacteria that make their home inside the human body, on human health is becoming increasingly well accepted in biology. How the microbiome impacts cancer, however, is not well studied. She suggests future research could focus on confirming the impact of CDD enzyme in pancreatic cancer cells. More generally, it is essential to study how other bacteria commonly found in humans interact with tumors.

Acknowledgments: Many thanks to Silvia Escudero for her insights on this article. Silvia works in the Pediatric Oncology Department at the Dana Farber Cancer Institute

Managing Correspondent: Emily Kerr

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