Background In molecular level, competing endogenous RNAs (ceRNAs) regulates other RNA transcripts through competing for shared microRNAs (miRNA). miRNA negatively regulate gene expression at the levels of mRNAs stability and translation suppression. Methods We tested the mRNA level of miR-218-5p and RNASEH1-AS1 in clinical lung squamous cell carcinoma tissues by qRT-PCR. In the exploring of the role of miR-218-5p and RNASEH1-AS1 in the malignant phenotype of NCI-H520 cells, colony formation and MTT assay were used to test the cell viability and proliferation capability, trans-well invasion and wound healing assay were performed to examine the cell migration and invasion. ChIP assay was conducted to confirm the direct interact of POU2F1 and RNASEH1-AS1 promoter. Results In this investigation, we found that LncRNA RNASEH1-AS1 is up-regulated in human lung cancer, and serves as a miRNA sponge for hsa-miR-218-5p in human lung squamous carcinoma cells. lncRNA RNASEH1-AS1 facilitates growth and motility of lung squamous carcinoma cells, while miR-218-5p does the opposite. NET1 and POU2F1 are validated as direct and functional targets of miR-218-5p. The downregulation of miR-218-5p releases the suppression of NET1 and POU2F1. POU2F1 binds directly to the lncRNA-RNASEH1-AS1 promoter and acts as transcription factor to enhance the promoter activity of RNASEH1-AS1. Conclusion Above all, the positive feedback loop of RNASEH1-AS1/ hsa-miR-218-5p/ NET1/ POU2F1 can help us to understand the regulatory mechanism behind genesis and progression of human lung squamous carcinoma, possibly providing new biomarkers for its diagnosis and treatment.

Background At the molecular level, competing endogenous RNAs (ceRNAs) regulate other RNA transcripts by competing for shared microRNAs (miRNA). Notably, miRNAs negatively regulate gene expression at the levels of mRNA stability and translation suppression.MethodsWe measured theexpression of miR-218-5p and RNASEH1-AS1 in clinical lung squamous cell carcinoma tissues using qRT-PCR. In an attempt to explore the roles of miR-218-5p and RNASEH1-AS1 in determining the malignant phenotype of NCI-H520 cells, colony formation and MTT assays were performed to measure cell viability and proliferation, and transwell invasion and wound healing assays were performed to examine cell migration and invasion. A ChIP assay was conducted to confirm the direct binding of POU2F1 to the RNASEH1-AS1 promoter.ResultsIn this investigation, the expression of the lncRNA RNASEH1-AS1 is upregulated in human lung cancer tissues, and it functions as a miRNA sponge for hsa-miR-218-5p in human lung squamous carcinoma cells. The lncRNA RNASEH1-AS1 facilitates the growth and motility of lung squamous carcinoma cells, while miR-218-5p exerts the opposite effects. NET1 and POU2F1 are validated as direct and functional targets of miR-218-5p. The downregulation of miR-218-5p releases the suppression of NET1 and POU2F1. POU2F1 binds directly to the lncRNA-RNASEH1-AS1 promoter and functions as transcription factor to enhance the promoter activity of RNASEH1-AS1.ConclusionsOverall, the positive RNASEH1-AS1/hsa-miR-218-5p/NET1/POU2F1 feedback loop can help us understand the regulatory mechanism underlying the genesis and progression of human lung squamouscarcinoma, possibly providing new biomarkers for its diagnosis and treatment.