Study On MicroRNA In Lung Cancer: Contain Regulation And Susceptibility

Lung cancer is the most frequently malignant tumor, which both the morbidity and mortality topped the list in our country. It brought serious impact on human health and socio-economic development It is an urgently public health problem that to finding effective targets and reliable biomarkers, and providing the basis for prevention, early diagnosis and targeted treatment of lung cancer. MircoRNA is a highly conserved noncoding short chain RNA. It recognized the target mRNA and regulated gene expression through complementary base pairing, which involved in multiple biological processes such as cell growth, differentiation, cell cycle and apoptosis. Previous studies showed that miRNA are closely related to cancer and act as oncogenes or tumor suppressor in tumorigenesis. However, the biological function and regulation mechanism of a lot of miRNAs are still not clear. The relationship between miRNA SNP and cancer susceptibility gradually attracted people’s attention. When a SNP occurs on miRNA, it may affect the biological function of miRNA, thereby affecting the risk of cancer.In present study, based on the bio informatics analysis, we investigated the biological function and target genes regulation of miR-202 and miR-1908 in lung cancer cells, and analyzed the action and molecular mechanism of miR-202 and miR-1908 on development of lung cancer. In addition, case-control study was adopted to explore the relationship between miR-202 rs12355840, miR-1908 rs174561, miR-608 rs4919510, miR-548j rs4822739 gene polymorphisms and lung cancer susceptibility. Then, cell experiment was offered to analyze whether rs12355840 and rs174561 affect mir-202 and mir-1908 expression, respectively. The results may provide biomarkers for the prevention, early detection and treatment of lung cancer.1. Research on miRNA regulation of lung cancerObjective To investigate the biological functions and target gene regulation mechanisms of miR-202 and miR-1908 in A549 lung cancer cells.Methods DIANA-TOOLs and KEGG database were used to analyze the bioinformatic of miR-202 and miR-1908, and explore the signaling pathways and the potential target genes. Through the lentivirus transfection, miR-202 and miR-1908 expression were up- and down-regulated in A549 cell. Then, MTT and flow cytometry technology were applied to detect the influence of miR-202 and miR-1908 on cell proliferation, apoptosis and cell cycle, respectively. RT-qPCR and Western Blot methods were applied to detect the regulation of miR-202 and miR-1908 on mRNA and protein of predicted target gene PIK3CAand PP5, respectively.Results Bioinformatics analysis showed that miR-202 was mainly to be involved in non-small cell lung cancer process and other tumor-related pathway, and possibly play its role through targeted PIK3CA. MiR-1908 mainly was to be related to MAPK signaling pathway, and PP5 were its important potential target gene. The biological function studies showed that, compared with the negative control group, up-regulation of miR-202 could inhibit cell proliferation, cause cell cycle G1/S phase arrest, but had no effect on cell apoptosis. Up-regulation of miR-1908 could cause cell cycle G2 arrest and S phase reduction, but not induce significant change in cell proliferation and apoptosis. Target gene study showed that, compared with the control group, the expression of PIK3CA protein was negatively correlated with miR-202, but the expression of its mRNA was no significant change. Compared with the negative control group, the expression of PP5 protein was positively correlated with miR-1908, but the expression of its mRNA was no significant change.Conclusion miR-202 might affect cell proliferation and cell cycle through the negative regulation to PIK3CA gene, and miR-1908 might affect cell cycle by the positive regulation to PP5 gene.2. Research on the miRNA gene polymorphis ms and lung cancer susceptibilityObjective To investigate the influence of miR-202 rs12355840, miR-1908 rs174561, miR-608 rs4919510 and miR-548j rs4822739 polymorphisms to lung cancer susceptibility.Methods Case-control study was adopted and epidemiological data and blood from 223 cases of lung cancer and 224 controls were collected. LDR method was used to detect miR-202 rs12355840, miR-1908 rs174561, miR-608 rs4919510, and miR-548j rs4822739 genotypes. Genotypes distribution and stratified analysis based on the pathological type and smoking status were offered to analyze the impact of miRNA SNP on lung cancer susceptibility. After transfected plasmid to A549 cells, RT-qPCR had been used to analyze the influence of miR-202 and miR-1908 polymorphism to the expression of miRNA.Results The case-control study results showed that miR-202 rs12355840, miR-1908 rs174561, miR-608 rs4919510 and miR-548j rs4822739 genotype distribution in the case group and the control group had no significant difference.After stratified by pathological type and smoking status, also found no effect of four miRNA SNP to lung cancer risk. RT-qPCR results showed that there was no significant difference about the miRNA expression between different allele transfection groups.Conclusion No relationship was found between SNPs of miR-202, miR-1908, miR-608 and miR-548j and lung cancer susceptibility. MiR-202 and miR-1908 polymorphism had no significant effect on miRNA expression.