MicroRNA miR-16-1 regulates CCNE1 (cyclin E1) gene expression in human cervical cancer cells

MicroRNAs are involved in diverse biological processes through regulation of gene expression. The microRNA profile has been shown to be altered in cervical cancer (CC). MiR-16-1 belongs to the miR-16 cluster and has been implicated in various aspects of carcinogenesis including cell proliferation and regulation of apoptosis; however, its function and molecular mechanism in CC is not clear. Cyclin E1 (CCNE1) is a positive regulator of the cell cycle that controls the transition of cells from G1 to S phase. In CC, CCNE1 expression is frequently upregulated, and is an indicator for poor outcome in squamous cell carcinomas (SCCs). Thus, in the present brief communication, we determine whether the CCNE1 gene is regulated by miR-16-1 in CC cells. To identify the downstream cellular target genes for upstream miR-16-1, we silenced endogenous miR-16-1 expression in cell lines derived from CC (C-33 A HPV-, CaSki HPV16+, SiHa HPV16+, and HeLa HPV18+ cells), using siRNAs expressed in plasmids. Using a combined bioinformatic analysis and RT-qPCR, we determined that the CCNE1 gene is targeted by miR-16-1 in CC cells. SiHa, CaSki, and HeLa cells demonstrated an inverse correlation between miR-16-1 expression and CCNE1 mRNA level. Thus, miR-16-1 post-transcriptionally down-regulates CCNE1 gene expression. These results, suggest that miR-16-1 plays a vital role in modulating cell cycle processes in CC.