Naltrexone has variable and schedule-dependent effects on oral squamous cell carcinoma cells

Oral squamous cell carcinoma is marked by profound differences in survival between localized and disseminated disease. While at its site of origin, oral cancer is frequently treated with surgery and/or radiation, leading to approximately 70% five-year survival. In metastatic cases, chemotherapy is preferred, but drug resistance and therapy failure is common in this setting, leading to five-year survival below 40%. New therapeutic approaches are therefore needed to supplement existing chemotherapies and improve outcomes. Naltrexone, an opioid antagonist most well-known for treatment of substance abuse, has been evaluated at low doses in other contexts, including inflammation, autoimmunity, and other forms of cancer. In this study, we sought to determine if intermittent dosing of naltrexone would impact oral cancer cell survival, either as a single agent or in combination with traditional chemotherapy. We found that its effects alone were negligible, but that combination with cytotoxic drugs may have promise as a novel treatment strategy. Further study and optimization will be needed to determine if these findings will be of clinical benefit.