Methadone Found Effective Against Leukemia Cell Cultures

Cancer researchers have found that the strong opiate methadone, used as a painkiller and as a tool to wean heroin addicts away from that drug, is a potent agent for the treatment of leukemia.

Investigators at the University of Ulm (Germany) choose to examine the possible effects of methadone on leukemia cells growing in laboratory culture because this cancer expresses the opioid receptor. They treated leukemia cell cultures, including cultures of drug resistant cell lines, to single doses of methadone that were greater than doses used to treat opioid addiction.

Results published in the August 1, 2008, issue of the journal Cancer Research revealed that methadone inhibited proliferation of leukemia cells and induced cell death through apoptosis induction, and it activated apoptosis pathways through the activation of caspase-9 and caspase-3. Methadone induced cell death not only in anticancer drug–sensitive and apoptosis-sensitive leukemia cells but also in doxorubicin-resistant, multidrug-resistant, and apoptosis-resistant leukemia cells, which anticancer drugs commonly used in conventional therapies of leukemias failed to kill. In contrast to leukemia cells, nonleukemic peripheral blood lymphocytes survived after methadone treatment.

"Methadone kills sensitive leukemia cells and breaks treatment resistance, but without any toxic effects on nonleukemic blood cells,” said senior author Dr. Claudia Friesen, professor of legal medicine at the University Ulm. "We find this very exciting, because once conventional treatments have failed a patient, which occurs in old and also in young patients, they have no other options.”

The investigators have initiated studies of methadone treatment in animal models of human leukemia, and do believe that additional types of cancers might be suitable for treatment with the drug.

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