Abstract: Objective To investigate the effects of miR-422a targeting kallikinase 4 (KLK4) on proliferation, migration and invasion of cervical cancer cells. Methods The expression levels of miR-422a in human cervical cancer cells (HeLa, SiHa) and human normal cervical epithelial cells (H8) were quantified by quantitative real-time PCR. Cervical cancer HeLa cells were divided into the blank group, the miR-NC group, the miR-422a group, the mut miR-422a group, the miR-422a+ pcDNA group and the miR-422a+pcDNA-KLK4 group. CCK-8 assay and transwell assay were used to detect the proliferation, migration and invasion of HeLa cells in each group. TargetScan software was used to predict the binding target genes. Double luciferase activity test was used to verify the targeting relationship. Western blot assay was used to detect the KLK4 protein expression in each group. Results Compared with normal human cervical epithelial cells H8, the expression levels of miR-422a were low in both cervical cancer HeLa cells and SiHa cell lines (P＜0.01), and cervical cancer HeLa cells were selected for the subsequent experiments. Compared with that in the miR-NC group and blank group, the OD450 of the miR-422a group decreased after cells were cultured for 4, 6 d, the numbers of invasion and migration cells decreased in the miR-422a group after cells were cultured for 6 and 12 h (P＜0.05). Compared with miR-422a+pcDNA group, OD450 of the miR-422a+pcDNA-KLK4 group was significantly increased at 4 and 6 d after culturing, and the number of cell migration and invasion was increased at 6 and 12 h after culturing (P＜0.01). TargetScan software predicted that there was a binding site between miR-422a and KLK4, which was verified by double luciferase reporter gene experiment. Compared with the miR-NC group, the expression level of KLK4 protein was decreased in the miR-422a group, and the expression level of KLK4 protein was increased in the mut miR-422a group (P＜0.01). Compared with the miR-422a+pcDNA group, the expression level of KLK4 protein increased in the miR-422a+pc DNA-KLK4 group (P＜0.01). Conclusion miR-422a can inhibit the HeLa cell proliferation, migration and invasion by targeting the KLK4 protein expression.

Key words: uterine cervical neoplasms, kallikreins, microRNAs, HeLa cells, cell proliferation, cell movement, cell invasion, miR-422a