miR-4293 Upregulates lncRNA WFDC21P by Directly Suppressing mRNA-Decapping Enzyme 2 to Promote Lung Carcinoma Proliferation

Background: Emerging evidence shows that lncRNA WFDC21P could promote STAT3 phosphorylation and microRNA 4293 SNP is associated with the risk of carcinomas, but the oncogenic functions of WFDC21P and miR-4293 in lung carcinoma are unclear.Methods: mRNA sequencing of lung carcinoma and control para-carcinoma tissues was performed to screen the potential targets. WFDC21P and miR-4293 levels were evaluated in lung carcinoma cells and tissues by qRT-PCR. The function of WFDC21P and miR-4293 on proliferation, apoptosis and metastasis were assessed by MTT, FACS, western blot, transwell assays, colony formation assays and xenografts experiment. RNA immunoprecipitation assays were implemented to verify the relationship between WFDC21P and mRNA-decapping enzyme 2 (DCP2). Furthermore, gain/loss of miR-4293 functions were used to determine its targeting relationship of DCP2. Results: WFDC21P expression is markedly enhanced in lung carcinoma tissue and cells. Moreover, WFDC21P promotes tumor cell proliferation and metastasis but suppresses apoptosis. Mechanistic investigations identified DCP2 can directly bind to WFDC21P and down-regulates its expression. DCP2 as a direct target of miR-4293 and its expression is suppressed by miR-4293. Consequently, miR-4293 can further promote WFDC21P expression by regulating DCP2. With positive correlation to WFDC21P expression, miR-4293 also plays oncogenic role in lung carcinoma. Furthermore, knockdown of WFDC21P results in functional attenuation of miR-4293 on tumor promotion. In vivo xenograft growth is also promoted by both WFDC21P and miR-4293. Conclusion: Our results establish oncogenic roles for both WFDC21P and miR-4293, and demonstrate that interactions between miRNAs and lncRNAs through DCP2 are important in lung carcinoma pathogenesis.