Expression And Clinical Significance Of MiR-21 In Nasopharyngeal Carcinoma And Its Effect On The Sensitivity Of Nasopharyngeal Carcinoma Cells To Cisplatin

Objective:To evaluate the expression and clinical significance of serum miR-21 in patients with nasopharyngeal carcinoma and its effect on the sensitivity of nasopharyngeal carcinoma cells to cisplatin.Methods:choosing77 cases of nasopharyngeal carcinoma patients and 30 healthy subjects,we used RT-PCR analysis to detect serum miR-21 expression,analyzing the correlation of serum miR-21 expression with clinical pathological characteristics of nasopharyngeal carcinoma and its relationship with the sensitivity of nasopharyngeal carcinoma to cisplatin chemotherapy.Furthermore,we respectively transfected two nasopharyngeal carcinoma cells,C666-1 and CNE2 with miR-21 mimic and miR-21 inhibit to regulate the expression of miR-21,and then analyzed the effect of miR-21 expression on the sensitivity of nasopharyngeal carcinoma cells to cisplatin by CCK8 assay.Results:The expression level of serum miR-21 was not correlated to age,gender and distant metastasis(P>0.05),but correlated to clinical stage and pathological grade(P<0.05).The expression of serum miR-21 in nasopharyngeal carcinoma patients was significantly higher than that in healthy people(P<0.05).The AUC,sensitivity and specificity of serum miR-21 for nasopharyngeal carcinoma diagnosis were 0.845,0.74 and 0.82,respectively.Compared with nasopharyngeal carcinoma patients with the low miR-21 expression,survival rate and overall survival rate of nasopharyngeal carcinoma patients with the high miR-21 expression were significantly decreased,and the drug resistance rate of cisplatin was significantly increased(P<0.05).Serum expression level of miR-21 in cisplatin resistance patients was significantly higher than that of patients with no drug resistance(P<0.05).The AUC,sensitivity and specificity of serum miR-21 for nasopharyngeal carcinoma with cisplatin resistance were 0.812,0.71 and 0.75,respectively.After receiving cisplatin chemotherapy,nasopharyngeal carcinoma patients with the high serum miR-21 expression had a lower disease-free and overall survival rates than those with the low serum miR-21 expression(P<0.05).To futher confirm the effect of miR-21 on cisplatin sensitivity,we overexpressed miR-21 mimic in C666-1 and CNE2 cells to test the influence of miR-21 on cell survival towards cisplatin,finding that miR-21 mimic enhanced miR-21 expression to decrease the suppressive effect of cisplatin on cell survival.Furthermore,miR-21 inhibit had the opposite effect.Conclusion:The increased serum miR-21 expression in nasopharyngeal carcinoma patients was positively correlated to the cisplatin chemotherapy resistance of nasopharyngeal carcinoma.