【Abstract】Objective To investigate the effect of miR2215p on proliferation, apoptosis and cisplatin sensitivity of nasopharyngeal carcinoma cells and its potential mechanism.Methods The expression of ALDH1a2 mRNA and miR 221 5p in human nasopharyngeal carcinoma cell lines SUNE1, HNE1 and CNE2 were detected by QRT PCR and Western blot. The expression of miR 221 5p and over expression of ALDH1a2 were inhibited in SUNE1 cells. The survival rate and sensitivity of SUNE1 cells to cisplatin were determined by MTT assay. The apoptosis rate was detected by flow cytometry. The expression of ALDH1a2, CyclinD1, cleave caspase 3 and MRP1 protein were detected by Western blot. The regulatory relationship between Mir 221 5p and ALDH1a2 was verified by dual luciferase reporter system.Results Compared with the control group, miR2215p was highly expressed and ALDH1A2 was poorly expressed in nasopharyngeal carcinoma cells SUNE1, HNE1 and CNE2. Inhibition of miR2215p and overexpression of ALDH1A2 both inhibited the proliferation, induced apoptosis and enhanced the sensitivity to cisplatin of SUNE1. miR2215p negatively regulates the expression of ALDH1A2. Inhibition of ALDH1A2 partially reversed the effects of miR2215p inhibition on SUNE1 cell proliferation, apoptosis, and cisplatin sensitivity. Conclusion Downregulation of miR2215p enhances the sensitivity of nasopharyngeal carcinoma SUNE1 cells to cisplatin, inhibits the proliferation of cancer cells and induces apoptosis by targeting and promoting the expression of ALDH1A2. miR2215p is expected to be a target for cisplatin sensitization in nasopharyngeal carcinoma. 