MiR-593 mediates curcumin-induced radiosensitization of nasopharyngeal carcinoma cells via MDR1

Abstract

Curcumin (Cur) exhibits radiosensitization effects to a variety of malignant tumors. The present study investigates the radiosensitizing effect of Cur on nasopharyngeal carcinoma (NPC) cells and whether its mechanism is associated with microRNA‑593 (miR‑593) and multidrug resistance gene 1 (MDR1). A clonogenic assay was performed to measure the radiosensitizing effect. The expression of miR‑593 and MDR1 was analyzed by quantitative polymerase chain reaction (qPCR) or western blot assay. A transplanted tumor model was established to identify the radiosensitizing effect in vivo. A luciferase-based reporter was constructed to evaluate the effect of direct binding of miR‑593 to the putative target site on the 3' UTR of MDR1. The clonogenic assay showed that Cur enhanced the radiosensitivity of cells. Cur (100 mg/kg) combined with 4 Gy irradiation inhibited the growth of a transplanted tumor model in vivo, resulting in the higher inhibition ratio compared with the radiotherapy‑alone group. These results demonstrated that Cur had a radiosensitizing effect on NPC cells in vivo and in vitro; Cur‑mediated upregulation of miR‑593 resulted in reduced MDR1 expression, which may promote radiosensitivity of NPC cells.