MiR-125B Modulates The Growth, Migration And Invasion Of Human Cutaneous Squamous Cell Carcinoma Cells

Cutaneous squamous cell carcinoma (cSCC) is one of the common skin cancers, and the increased propensity of cSCC to metastasize and recur makes them responsible for the majority of the deaths. Therefore, to discover a novel biomarker responsible for the development of cSCC is crucial for its diagnosis and treatment.microRNAs (miRNAs) are a family of endogenous, small non-coding single RNA molecules that regulate gene expression at the post-transcriptional level. Their deregulation is associated with cancer initiation and development. In this study, the aim is to detect the roles and regulation mechanism of miR-125b in cSCC cells.The study was indived into four parts:1. We performed TLDA in cSCC and healthy skin tissues to detect the differentially expressed miRNAs, then quantitative real time PCR and in situ hybridization were performed among cSCC, actinic keratoses and healthy skin tissues, even in the cSCC tissues with different grades, respectively.2. We overexpressed miR-125b by transfecting the cells with miR-125b precursor in UT-SCC-7and A431cells. Then we observed the cell proliferation, colony formation, migration and invasion, and also the cell apoptosis.3. Bioinformatics and genechip were used for predicting the target genes for miR-125b. Then luciferase reporter assay, quantitative real time PCR and western blot were used for targets validation. Finally, functional studies were performed when the target genes were knockdown using siRNA technique. Besides the targets, we also explored the possible signal pathways of miR-125b involved in cellular processes.4. We analyzed the promoter region of miR-125b and treated the cells with5-aza, then miR-125b expression was evaluated by real time PCR. We also detected the effect of the KGF on miR-125b levels.The conclusion was shown as follows:1. miR-125b was downregulated in cSCC tissues, but miR-125b had no effect on the differentiation.2. miR-125b inhibited the colony formation, cell proliferation, migration and invasion, but contributed to cell apoptosis. 3. MMP-13and MAP2K7were validated as direct targets for miR-125b and miR-125b suppressed the targets expression on both mRNA and protein levels. In addition, there existed an inverse relationship between the targets and miR-125b expression. Additionally, MMP-7, TGFBR2, TP53INP1, cyclinD1and c-Jun were also regulated by miR-125b. The knockdown of MMP-13inhibited the colony formation, migration and invasion, while knockdown of MAP2K7inhibited the cell proliferation and contributed to apoptosis.4. miR-125b expression was increased after5-aza treatment, suggesting that miR-125b may be hypermethylated. In addition, miR-125b expression was reduced after KGF treatment.