Fasting for two days protects healthy cells against chemotherapy, according to a study appearing online the week of Mar. 31 in PNAS Early Edition.
Mice given a high dose of chemotherapy after fasting continued to thrive. The same dose killed half the normally fed mice and caused lasting weight and energy loss in the survivors.
The chemotherapy worked as intended on cancer, extending the lifespan of mice injected with aggressive human tumors, reported a group led by Valter Longo of the University of Southern California.
Test tube experiments with human cells confirmed the differential resistance of normal and cancer cells to chemotherapy after a short period of starvation.
Making chemotherapy more selective has been a top cancer research goal for decades. Oncologists could control cancers much better, and even cure some, if chemotherapy were not so toxic to the rest of the body.
Experts described the study as one of a kind.
This is a very important paper. It defines a novel concept in cancer biology, said cancer researcher Pinchas Cohen, professor and chief of pediatric endocrinology at the University of California, Los Angeles.
In theory, it opens up new treatment approaches that will allow higher doses of chemotherapy. Its a direction thats worth pursuing in clinical trials in humans.
Felipe Sierra, director of the Biology of Aging Program at the National Institute on Aging, said: This is not just one more anti-cancer treatment that attacks the cancer cells. To me, thats an important conceptual difference.
Sierra was referring to decades of efforts by thousands of researchers working on targeted delivery of drugs to cancer cells. Study leader Longo focused instead on protecting all the other cells.
Sierra added that progress in cancer care has made patients more resilient and able to tolerate fasting, should clinical trials confirm its usefulness.
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|Contact: Carl Marziali|
University of Southern California