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Common pain killers like morphine can promote cancer cell growth, according to a new study.
Opiate-based painkillers have been shown to encourage cancer growth. Two new studies have revealed how protecting lung cancer cells from opiates reduce cell production, invasion and migration in both cell-culture and mouse models.
The researchers concentrated on the mu opiate receptor, where morphine works, as a potential remedial target.
"If confirmed clinically, this could change how we do surgical anesthesia for our cancer patients," said Dr Patrick A. Singleton, Assistant Professor of medicine at the University of Chicago Medical Center and principal author of both studies.
"It also suggests potential new applications for this novel class of drugs which should be explored," he added.
A 2002 palliative-care trial revealed that patients who received spinal rather than systemic pain relief lived longer. Soon after that, Singleton''s colleague, Jonathan Moss, an anesthesiologist, noted that many cancer patients receiving a selective opiate blocker in a compassionate-use procedure lived longer than expected.
Moss’s palliative-care patients were taking methylnaltrexone (MNTX), developed in the 1980s for opiate-induced constipation by the late University of Chicago pharmacologist Leon Goldberg. He customised an established drug that obstructs morphine so that it could no longer cross the protective barrier that surrounds the brain.
So MNTX blocks morphine’s marginal side effects but does not interfere with its effect on pain, which is centered in the brain.
"These were patients with advanced cancer and a life expectancy of one to two months," Moss recalled, "yet several lived for another five or six. It made us wonder whether this was just a consequence of better GI function or could there possibly be an effect on the tumours."
The finding was presented at "Molecular Targets and Cancer Therapeutics," a joint conference in Boston of the American Association for Cancer Research, the National Cancer Institute, and the European Organization for Research and Treatment of Cancer.
