DL-Methadone as an Enhancer of Chemotherapeutic Drugs in Head and Neck Cancer Cell Lines

Background/Aim: The aim of this study was to analyze the effect of DL-methadone on enhancing the action of the chemotherapeutic drugs cisplatin, doxorubicin, 5-fluoruracil (5-FU) and paclitaxel on head and neck squamous carcinoma (HNSCC) cell lines. Materials and Methods: The chemotherapeutic drugs were applied alone or in combination with DL-methadone and cytotoxicity was analyzed by XTT assays. Expression of the mu-opioid receptor and the drug transporter p-glycoprotein were analyzed by qRT-PCR. Results: The effect of DL-methadone strongly depended on the respective chemotherapeutic agent. The basic expression of the mu-opioid receptor was not associated with the effect of DL-methadone, rather its induction by chemotherapeutic drugs. Expression or expression induction of p-glycoprotein was higher in weak-responder cell lines. Conclusion: Enhancement of the toxicity of chemotherapeutic drugs by DL-methadone depends on the drug and on the cell line used.