Study Of The Expression Of MiR-155in Gastric Cancer And Impact On Proliferation And Apoptosis Of Human Gastric Cancer Cell

Objective: To examine the expression and clinical significance of miRNA-155ingastric cancer. Meanwhile, we transfected SGC-7901cells line with miR-155mimics,investigated the effects of transfection on cell proliferation, cell cycle, apoptosis inSGC-7901cell line. Probe the biological role of miR-155in gastric cancer (GC), lay thefoundation for target gene therapy of GC.Methods1.We detected miR-155expression levels by quantitative real‐time PCR(qRT-PCR)in42gastric cancer (GC) tissues, their corresponding adjacent non‐tumor tissues(NATS),and analyzed the correlation with its related clinicopathologic features of gastriccancer,such as age,sex,location,size,local invasion,histological grade,venousinvasion,TNM stage.2. Gastric cancer line SGC-7901was transfected with lipofectamineTM2000andFAM-NC-sequence.The transfection efficiency of miR-155mimics was detected byfluorescence microscopy.The mimics of miR-155expression was analyzed by stem-loopprimers SYBR-GREE real-time quantitative PCR after transfecting the miR-155mimics.Cell proliferation was tested by CCK8method.Cell cycle and apoptosis were analyzed byusing flow cytometry.Results:1.The expression of miR-155was lower in GC tissues than in their adjacentnon-tumor tissue samples(NATs). Moreover, low expression of miR-155was associatedwith indicators of enhanced malignant potential, such as the size of tumor and regionallymph node metastasis(P<0.05).There were no obvious correlation with age,sex,location,local invasion,histological grade,venous invasion,TNM stage. 2.Through the experimental exploration,the best transfect condition is every wellcontain1.5×106cells,the density of siRNA is about80pmol/μL,theLipofectamine2000:mimics is about5ul:5ul,Continue to improve siRNA concentrationsdid not significantly improve the efficiency of transfection.Gastric cancer cell lineSGC-7901was transfected with miRNA mimics that up-regulated the expression ofmiR-155. Successful transfection was confirmed by qRT-PCR. We also demonstrated thatmiR-155mimics suppressed the proliferation of gastric cancer cells, promoted theirapoptosis,but the cell cycle was not impacted.Conclusion:All together, we found expression levels of miR-155are lower in tumor thanNATs.Up-regulation expression of miR-155is associated with the size of tumor andregional lymph node metastasis.After up-regulation of miR-155,the proliferation ofSGC-7901cell line decreased and the apoptosis of SGC-7901cell increased.Low-expression of miR-155might serve as a novel prognostic marker and potential targetfor cancer diagnosis and gene therapy.