Despite radiotherapy is an effective regimen in cancer treatment, resistance to tumor therapy still is a major challenge to radiotherapy and results in cancer recurrence and metastasis. Then the sensitization of tumor cells to ionizing radiation (IR) would be beneficial in cancer treatment. The aim of this study was to evaluate the synergistic effect of mefenamic acid (MEF) on colon cancer cell (HT-29) exposure to IR. HT-29 cells were treated with MEF and then exposed to IR. The synergistic effect of MEF is evaluated by clonogenic assay and flow cytometry. The productions of reactive oxygen species (ROS) were determined in irradiated and treated cells with MEF. The findings of this study showed that MEF had anti-cancer effect on colon cancer cell line and it increased the apoptosis in irradiated HT-29 cells. Also MEF reduced the number of cell colonies when HT-29 cells pre-treated with MEF and irradiated. MEF increased ROS production in irradiated cells. This additive effect of MEF with IR in killing of HT-29 cell was observed at low (10 μM) and medium (100 μM) concentrations of MEF. The present study demonstrates that MEF to be an additive effect on apoptosis and cell death induced by IR in colon cancer cells.
Keywords: Apoptosis; Ionizing radiation; Mefenamic acid; Synergistic, radiosensitizing.