Abstract
Objective:This study explored the effect of nanoparticle-encapsulated curcumin on the highly expressed multidrug resistance gene 1 （MDR1） in a human low-differentiated nasopharyngeal carcinoma cell line （CNE2）. Methods:Curcumin/chitosan deoxycholic acid nanoparticles were prepared, and the cells were subjected to different treatments: radiotherapy, empty carriers, curcumin, and curcumin-loaded nanoparticles. Cell survival was analyzed using the clonogenic assay, and assessments of apoptosis, MDR1 levels, and miR593 levels were conducted. Results:The cell survival fractions in the curcumin group and the curcumin-loaded nanoparticles group were significantly reduced. Notably, higher apoptosis rates were observed in cells treated with curcumin or curcumin-loaded nanoparticles compared to those that received only radiotherapy. Moreover, a decreased MDR1 level was noted in both the curcumin group and the curcumin-loaded nanoparticles group, with further reduction in MDR1 expression observed in the nanoparticle group （P<0.05）. Enhanced expression of miR593 was found in the curcumin group and the curcumin-loaded nanoparticles group, with a relatively higher level in the nanoparticle group （P<0.05）. Curcumin encapsulated in nanoparticles exhibited a stronger radiosensitizing effect. The combination of curcumin and radiotherapy effectively inhibited nasopharyngeal carcinoma （NPC） tumor growth, suppressed MDR1 expression, and enhanced miR593 levels. After inhibiting miR593, MDR1 expression increased. The radiosensitizing effect of curcumin-loaded nanoparticles was regulated by miR593 rather than being triggered by MDR1. Conclusion:Curcumin-loaded nanoparticles mediated enhanced expression of miR593, which in turn inhibited the transcription and translation of the MDR1 gene, thereby reducing the radioresistance of NPC and effectively restraining its growth.