Objective To investigate the effect of microRNA-134 （miR-134） on suppressing the proliferation of non-small cell lung cancer（NSCLC）and the possible mechanism. Methods The expression levels of miR-134 in NSCLC cell lines（A549，H252）and human embryo lung WI38 cells were detected by real-time quantitative PCR（QPCR）. A549 and H252 cell lines were divided into miR-NC group，miR-134 group and blank control group，which were transfected with control-siRNA，miR-134 mimics and none，respectively. The proliferation in the three groups of A549 and H252 cells was detected by MTS assays 24，48，72，96 h after transfect. Cell apoptosis were detected by flow cytometry after 96 h. A luciferase reporter assay was performed to confirm whether epidermal growth factor receptor（EGFR was a direct target of miR-134. The expression level of EGFR was detected by QPCR. Results The level of miR-134 was found down-regulated 85.91％ in A549 cells and 78.13％ in H252 cells comparing with it in WI38 cells（P＜0.05）. MTS assays showed that miR-134 suppressed A549 and H252 cells proliferation significantly in a time-depended manner. Flow cytometry showed that the apoptotic rate of A549 and H252 cells increased to 226.31％ and 47.85％ respectively compared with blank control group（P＜0.05）. A dual-luciferase reporter assay confirmed that EGFR was a direct target of miR-134 by reducing the activity of luciferase（P＜0.05）. QPCR showed that after the transfect of miR-134 mimics，the expression of EGFR down-regulated 57.0％ in A549 cells and 35.0％ in H252 cells compared with blank control group（P＜0.01）. Conclusion miR-134 is down-regulated in NSCLC and inhibites cells growth，as well as induces cell apoptosis by targeting EGFR in NSCLC.

Objective To explore the effect of small interfering RNA（siRNA）targeting protein arginine methyltransferase 5（PRMT5）on the proliferation and colony-formation in human gastric cancer SGC7901 cells. Methods siRNA-1 and siRNA-2 designed for specific targeting PRMT5 were transiently transfected into SGC7901 cells. Meanwhile，antisense sequence was used as negative control（NC）. 48 h after transfection，Western blotting method was used to confirm the interfering efficacy to ensure that siRNA can be used for following experiments. CCK-8 assay was used to detect the proliferation of SGC7901 cells after gene-specific siRNA was transfected. EdU assay was used to examine the DNA replication of SGC7901 cells and plate colonyformation assay was used to evaluate the colony-formation of SGC7901 cells when PRMT5 was silenced by siRNA. Results The level of PRMT5 protein was significantly decreased in SGC7901 cells when siRNA-1 and siRNA-2 were transfected，suggesting that siRNA-1 and siRNA-2 could be used for further studies. The proliferation rate of SGC7901 cells was significantly reduced when PRMT5 was silenced（P＜0.01）in comparison with NC. Compared with NC，the positive rates of EdU cells interfered by siRNA-1 and siRNA-2 in PRMT5 group were（16.0±2.0）％ and（19.5±3.0）％，much lower than（38.0±4.0）％ in NC with significance（P＜0.01）. Furthermore，the numbers of SGC7901 colonies in PRMT5 group interfered by siRNA-1 and siRNA-2 were 50±6 and 68±7，lower than 120±11 of NC with significance（P＜0.01）. Conclusion Knockdown of PRMT5 by gene-specific siRNA can inhibit the proliferation and colony-formation abilities in human gastric cancer SGC7901 cells，which provide new methods and theoretical basis for the treatment of gastric cancer.

Objective To explore the effect of microRNA-373（miR-373）on the expression of large tumor suppressor 2（LATS2）and its influence on the proliferation and apoptosis of hepatocellular carcinoma cell line HepG2. Methods The miR-373 level was detected in HepG2 cells and normal hepatocytes LO2 by fluorescence real-time quantitative PCR（QPCR）. HepG2 cells were assigned into inhibitor group and control group，and transfected with miR-373 inhibitors or negative control（NC）by Lipofectamine liposome method. The miR-373 levels of both groups were detected by QPCR in order to evaluate the transfection efficiency. MTT method and flow cytometry were used to detect the cell proliferation and apoptosis. The expressions of apoptosis related genes（Bax and caspase-3）and LATS2 in each group were detected by Western blotting. The relationship between miR-373 and LATS2 was verified using double luciferase reporter assay. Results Compared with LO2 cells，the level of miR-373 in HepG2 cells was increased，and the difference was statistically significant（P＜0.05）. The level of miR-373 in the inhibition group was lower than that of control group（P＜0.05）， indicating that the miR373 expression of HepG2 cells was inhibited successfully. Compared with control group，there were decreased proliferative rate, and increased apoptotic rate and protein levels of Bax，caspase-3 and LATS2 in inhibitor group（P＜0.05）. Dual luciferase reporter assay showed that miR-373 could significantly inhibit the luciferase activity of cells transfected with wild-type LATS2-3’UTR，and had no effect on luciferase activity of cells transfected with mutant LATS2-3’ UTR. Conclusion MiR-373 can regulate the expression of LATS2，and inhibiting the expression of miR-373 can inhibit the proliferation and induce apoptosis of HepG2 cells，providing some reference for the targeted therapy of hepatocellular carcinoma.

ObjectiveTo investigate the effect of small interfering RNA（siRNA）targeting tripartite motif-containing 29 （TRIM29）on the proliferation，apoptosis and invasion of osteosarcoma cells. Methods The levels of TRIM29 in osteosarcoma cell lines （MG63 and U2OS）were detected by fluorescence real-time quantitative PCR（QPCR）assay. Two siRNA fragments（siTRIM29-1 and siTRIM29-2 were efficiently transfected into MG63 and U2OS cells by lipofectamine method,and MG63 and U2OS cells transfected with siControl were set as control. The highest inhibitive efficiency of siRNA was selected for subsequent functional study. The proliferation，apoptosis and invasion of MG63 and U2OS cells after transfection were evaluated by MTT，flow cytometry and Transwell assay. Results The results of QPCR test showed that TRIM29 mRNA of MG63 and U2OS cells were significantly higher than those of normal osteoblast cell line hFOB1-19（P＜0.05）. Transfection of TRIM29 siRNA could reduce the TRIM29 level of MG63 and U2OS cells at 72 h. Compared with the cells transfected with siControl，there were decreased survival rates and transmembrane cell number, but increased apoptotic rates in transfection group with statistical significance（P＜0.05）. Conclusion TRIM29 is highly expressed in osteosarcoma cells，and silencing of TRIM29 can inhibit the proliferation and invasion of osteosarcoma cells and induce cell apoptosis， which can be used as reference in the treatment of osteosarcoma.

Objective To explore the relationship between the expression of DNA methylation and microRNA-328（miR-328）as well as the association of miR-328 with clinicopathological features and prognosis of invasive breast cancer.Methods In a retrospective analysis，the miR-328 expression levels of 1090 cases of invasive breast cancer tissues and 104 cases of adjacent tissues from TCGA breast cancer microarray from January 1998 to December 2013 were collected. The methylation rates of miR-328 CpG promoter region（cg16421621 and cg04650403）and correlation of methylation rates of CpG sites with the level of miR-328 were analyzed from 775 cases of invasive breast cancer tissues and 98 cases of adjacent tissues obtained from TCGA_BRCA_hMethyl450 microarray data. From the clinical_data_dictionary UCSC Genome Browser chip data，854 cases with complete clinicopathological data and follow-up data of breast cancer specimens were included for the analysis of the relationship of miR-328 with clinicopathological features and prognosis. The prognostic factors affecting the prognosis were exploited using Cox multivariate analysis. Results From January 1998 to December 2013, TCGA database of 1194 cases of breast cancer and adjacent tissues with expression of miR-328 showed that the miR-328 level of 1090 cases of invasive breast cancer tissues was 5.224 ±1.155，lower than 6.246±0.923 of 104 cases of adjacent tissues，and the difference was statistically significant（P＜0.01）. The methylation rates of cg16421621 and cg04650403 in the promoter region of miR-328 were（0.415±0.201）% and（0.193±0.068）% in 775 cases of invasive breast cancer，higher than（0.407±0.222）% and （0.094±0.079）% of 98 cases of adjacent tissues（P＜0.01）. The expression of miR-328 in invasive breast cancer was negatively correlated with the methylation rate of CG sites（cg16421621 and cg04650403）in the promoter region（r=-0.127，P=0.005）. In 854 cases of invasive breast cancer patients with complete clinical data, the expression level of miR328 was related to lymph node metastasis and tumor size（P＜0.05）. In miR-328 low expression group，the median overall survival（OS）was 7.25 years，lower than 8.75 years of high expression group（P＜0.01）. Cox multivariate analysis showed that age，lymph node metastasis and miR328 expression were independent factors influencing OS（P＜0.05），and the risk of high expression group was lower than that of low expression group（P＜0.01）.Conclusion MiR-328 expression is regulated by methylation of the promoter region of its gene in invasive breast cancer. MiR-328 is associated with clinicopathological features of invasive breast cancer，and can be used as a risk factor influencing the prognosis of invasive breast cancer.