Enhancing the sensitivity of nasopharyngeal carcinoma cells to cisplatin with MiR-139-5p by targeting CXCR4/PI3K/Akt signaling pathway

Abstract

Objective To investigate the effects and molecular mechanisms of miR-139-5p on cisplatin sensitivity of nasopharyngeal carcinoma cisplatin-resistant cells. Methods The cultured nasopharyngeal carcinoma cisplatin (DDP) resistant cell line HNE1/DDP cells were divided into miR-139-5p group, negative control group, DDP group and blank control group.The miR-139-5p group was transfected with miR-139-5p mimics and the negative control group was transfected with negative control sequences. The DDP group and the blank control group were not treated. After transfection, 20 μmol/L DDP was added to the miR-139-5p group, negative control group, and DDP group. The blank control group was only given the medium, and the apoptosis rate of each group of HNE1/DDP cells was detected by single staining with propiodide (PI). The expression levels of phosphatidylinositid 3-kinase(PI3K), p-PI3K, protein kinase B(Akt), p-Akt and chemokine receptor 4(CXCR4) proteins in miR-139-5p group, negative control group and blank control group were detected by Western blot. The mRNA expression levels of CXCR4 in miR-139-5p group, negative control group and blank control group were detected by real-time quantitative PCR (RT-qPCR). Results The apoptosis rate detection of HNE1/DDP cells showed that the apoptosis rate of blank control group, DDP group, negative control group and miR-139-5p group were 6.26%±1.19%, 22.43%±3.88%, 23.87%±3.21% and 40.87±4.04%, respectively. The apoptosis rates of DDP group, negative control group and miR-139-5p group were significantly higher than that of the blank control group, and the apoptosis rate of miR-139-5p group was significantly higher than those of DDP group and negative control group. The difference was statistically significant (all P values<0.05). Western blot analysis showed that the relative expression levels of p-Akt, p-PI3K, PI3K, and CXCR4 proteins in miR-139-5p group were significantly lower than those in blank control group and negative control group (all P values<0.01) . The results of RT-qPCR showed that the mRNA expression level of CXCR4 in the miR-139-5p group was significantly lower than those in the blank control group and the negative control group, and the difference was statistically significant (all P values<0.01). Conclusions Transfection of miR-139-5p can significantly increase the sensitivity of nasopharyngeal carcinoma cell line HNE1/DDP to cisplatin, which may be related to the inhibition of the expression of CXCR4 and the regulation of the activation of its downstream PI3K/Akt signaling pathway. Key words: Nasopharyngeal neoplasms; Drug resistance, neoplasm; Micro RNA; Cisplatin; Phosphatidylinositid 3-kinase; Protein kinase B; Chemokine receptor 4