miR-382-3p靶向RASA1基因调控骨关节炎软骨细胞增殖和凋亡

目的:探讨mi R-382-3p对骨关节炎软骨细胞增殖和凋亡的影响及其机制。方法:用100 ng/mL的脂多糖(LPS)处理软骨细胞,记为LPS组,以正常培养的软骨细胞作为正常对照(NC)组。mi R-NC、mi R-382-3p、anti-miR-NC、anti-miR-382-3p转染至软骨细胞中,记为mi R-NC组、mi R-382-3p组、anti-miR-NC组、anti-miR-382-3p组;将mi R-NC、mi R-382-3p、si-NC、si-RASA1转染至软骨细胞后再用100 ng/mL的LPS处理,记为mi R-NC+LPS组、mi R-382-3p+LPS组、si-NC+LPS组、si-RASA1+LPS组;将mi R-382-3p分别与pcDNA-NC、pcDNA-RASA1共转染至软骨细胞后再用100 ng/mL的LPS处理,记为mi R-382-3p+pcDNA-NC+LPS组、mi R-382-3p+pcDNA-RASA1+LPS组。实时荧光定量PCR(RT-qPCR)检测mi R-382-3p和Ras p21蛋白活化因子1(RASA1)m RNA表达水平;蛋白质印迹(Western blot)法检测RASA1、细胞周期蛋白D1(CyclinD1)、裂解的半胱氨酸天冬氨酸蛋白酶-3(Cleaved-caspase-3)蛋白表达;四甲基偶氮唑盐比色法(MTT)检测细胞存活率;流式细胞术检测细胞凋亡;荧光素酶报告实验检测mi R-382-3p和RASA1的靶向关系。结果:LPS诱导的软骨细胞中mi R-382-3p表达水平显著降低,RASA1表达水平显著升高,CyclinD1表达水平显著降低,Cleaved-caspase-3表达水平显著升高,细胞存活率显著降低,细胞凋亡率显著升高(P0.05)。过表达mi R-382-3p和敲减RASA1,LPS诱导的软骨细胞中CyclinD1表达水平显著升高,Cleaved-caspase-3表达水平显著降低,细胞存活率显著升高,细胞凋亡率显著降低(P0.05)。mi R-382-3p靶向调控RASA1,高表达RASA1部分逆转了mi R-382-3p高表达对LPS处理的软骨细胞增殖和凋亡的影响。结论:过表达mi R-382-3p促进软骨细胞增殖,抑制LPS诱导的软骨细胞凋亡,其机制可能与RASA1有关。     

Role of microRNA-26b in glioma development and its mediated regulation on EphA2

Background

MicroRNAs (miRNAs) are short, non-coding RNAs that regulate the expression of multiple target genes. Deregulation of miRNAs is common in human tumorigenesis. Low level expression of miR-26b has been found in glioma cells. However, its underlying mechanism of action has not been determined.

Methodology/Principal Findings

Real-time PCR was employed to measure the expression level of miR-26b in glioma patients and cells. The level of miR-26b was inversely correlated with the grade of glioma. Ectopic expression of miR-26b inhibited the proliferation, migration and invasion of human glioma cells. A binding site for miR-26b was identified in the 3′UTR of EphA2. Over-expression of miR-26b in glioma cells repressed the endogenous level of EphA2 protein. Vasculogenic mimicry (VM) experiments were performed to further confirm the effects of miR-26b on the regulation of EphA2, and the results showed that miR-26b inhibited the VM processes which regulated by EphA2.

Significance

This study demonstrated that miR-26b may act as a tumor suppressor in glioma and it directly regulates EphA2 expression. EphA2 is a direct target of miR-26b, and the down-regulation of EphA2 mediated by miR-26b is dependent on the binding of miR-26b to a specific response element of microRNA in the 3′UTR region of EphA2 mRNA.     

miR-101 is down-regulated by the hepatitis B virus x protein and induces aberrant DNA methylation by targeting DNA methyltransferase 3A

The hepatitis B virus x (HBx) protein has been implicated in HBV-related hepatocellular carcinoma (HCC) pathogenesis. However, whether HBx regulates miRNA expression that plays important roles in gene regulation during hepatocarcinogenesis remains unknown. The expression of microRNA-101 (miR-101) in HBV-related HCC tissues and HCC cells was evaluated by real-time PCR. The direct target of miR-101, DNA methyltransferase 3A (DNMT3A), was identified in silico and validated using a 3′-UTR reporter assay. miR-101 was functionally characterized in cells with transiently altered miR-101 expression. HBx expression was found to have a significant inverse correlation with miR-101 expression in HBx-expressing HepG2 compared to control HepG2 cells. miR-101 expression was frequently down-regulated in HBV-related HCC tissues compared to adjacent noncancerous hepatic tissues and had a significant inverse correlation with DNMT3A expression in HBV-related HCCs. Further characterization of miR-101 revealed that it negatively regulated DNA methylation partly through targeting DNMT3A. HBx-mediated miR-101 down-regulation and DNMT3A up-regulation supported the enhanced DNA methylation of several tumor-suppressor genes in HBx-expressing cells. Our studies demonstrating the deregulation of miR-101 expression by HBx may provide novel mechanistic insights into HBV-mediated hepatocarcinogenesis and identify a potential miRNA-based targeted approach for treating HBV-related HCC.     

miR-503 represses human cell proliferation and directly targets the oncogene DDHD2 by non-canonical target pairing

Background

The pathways regulating the transition of mammalian cells from quiescence to proliferation are mediated by multiple miRNAs. Despite significant improvements in our understanding of miRNA targeting, the majority of miRNA regulatory networks are still largely unknown and require experimental validation.

Results

Here we identified miR-503, miR-103, and miR-494 as negative regulators of proliferation in primary human cells. We experimentally determined their genome wide target profiles using RNA-induced silencing complex (RISC) immunoprecipitations and gene expression profiling. Analysis of the genome wide target profiles revealed evidence of extensive regulation of gene expression through non-canonical target pairing by miR-503. We identified the proto-oncogene DDHD2 as a target of miR-503 that requires pairing outside of the canonical 5′ seed region of miR-503, representing a novel mode of miRNA-target pairing. Further bioinformatics analysis implicated miR-503 and DDHD2 in breast cancer tumorigenesis.

Conclusions

Our results provide an extensive genome wide set of targets for miR-503, miR-103, and miR-494, and suggest that miR-503 may act as a tumor suppressor in breast cancer by its direct non-canonical targeting of DDHD2.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-015-1279-9) contains supplementary material, which is available to authorized users.     

Anticancer bioactive peptide-3 inhibits human gastric cancer growth by targeting miR-338-5p

Background

Cancer incidence and mortality have been increasing in China, making cancer the leading cause of death since 2010 and a major public health concern in the country. Cancer stem cells have been studied in relation to the treatment of different malignancies, including gastric cancer. Anticancer bioactive peptide-3 (ACBP-3) can induce the apoptosis of gastric cancer stem cells (GCSCs) and reduce their tumorigenicity. In the present study, for the first time, we used a miRNA microarray and bioinformatics analysis to identify differentially expressed miRNAs in ACBP-3-treated GCSCs and GCSC-derived tumors in a xenograft model and functionally verified the identified miRNAs. miR-338-5p was selected based on its significant upregulation by ACBP-3 both in cultured GCSCs and in tumor tissues.

Results

miR-338-5p was downregulated in GCSCs compared with normal gastric epithelial cells, and the ectopic restoration of miR-338-5p expression in GCSCs inhibited cell proliferation and induced apoptosis, which correlated with the upregulation of the pro-apoptotic Bcl-2 proteins BAK and BIM. We also found that ACBP-3-treated GCSCs could respond to lower effective doses of cisplatin (DDP) or 5-fluorouracil (5-FU), possibly because ACBP-3 induced the expression of miR-338-5p and the BAK and BIM proteins and promoted GCSC apoptosis.

Conclusions

Our data indicate that miR-338-5p is part of an important pathway for the inhibition of human gastric cancer stem cell proliferation by ACBP-3 combined with chemotherapeutics. ACBP-3 could suppress GCSC proliferation and lower the required effective dose of cisplatin or 5-fluorouracil. Therefore, this study provides not only further evidence for the remarkable anti-tumor effect of ACBP-3 but also a possible new approach for the development of GCSC-targeting therapies.

     

MiR-155 promotes proliferation of human breast cancer MCF-7 cells through targeting tumor protein 53-induced nuclear protein 1

Background

MiR-155 has emerged as an “oncomiR”, which is the most significantly up-regulated miRNA in breast cancer. However, the mechanisms of miR-155 functions as an oncomiR are mainly unknown. In this study, the aims were to investigate the effects of miR-155 on cell proliferation, cell cycle, and cell apoptosis of ERalpha (+) breast cancer cells and to verify whether TP53INP1 (tumor protein 53-induced nuclear protein 1) is a target of miR-155, and tried to explore the mechanisms of miR-155 in this process.

Results

The expression of miR-155 is significantly higher in MCF-7 cells compared with MDA-MB-231 cells. Ectopic expression of TP53INP1 inhibits growth of MCF-7 cells by inducing cell apoptosis and inhibiting cell cycle progression. Overexpression of miR-155 increases cell proliferation and suppress cell apoptosis, whereas abrogating expression of miR-155 suppress cell proliferation and promotes cell apoptosis of MCF-7 cells. In addition, miR-155 negatively regulates TP53INP1 mRNA expression and the protein expression of TP53INP1, cleaved-caspase-3, -8, -9, and p21, and luciferase reporter reveals that TP53INP1 is targeted by miR-155.

Conclusions

TP53INP1 is the direct target of miR-155. MiR-155, which is overexpressed in MCF-7 cells, contributes to proliferation of MCF-7 cells possibly through down-regulating target TP53INP1.     

Hepatitis B virus X protein mutant HBxΔ127 promotes proliferation of hepatoma cells through up-regulating miR-215 targeting PTPRT

The mutant of virus is a frequent event. Hepatitis B virus X protein (HBx) plays a vital role in the development of hepatocellular carcinoma (HCC). Therefore, the identification of potent mutant of HBx in hepatocarcinogenesis is significant. Previously, we identified a natural mutant of the HBx gene (termed HBxΔ127). Relative to wild type HBx, HBxΔ127 strongly enhanced cell proliferation and migration in HCC. In this study, we aim to explore the mechanism of HBxΔ127 in promotion of proliferation of hepatoma cells. Our data showed that both wild type HBx and HBxΔ127 could increase the expression of miR-215 in hepatoma HepG2 and H7402 cells. However, HBxΔ127 was able to significantly increase miR-215 expression relative to wild type HBx in the cells. We identified that protein tyrosine phosphatase, receptor type T (PTPRT) was one of the target genes of miR-215 through targeting 3′UTR of PTPRT mRNA. In function, miR-215 was able to promote the proliferation of hepatoma cells. Meanwhile anti-miR-215 could partially abolish the enhancement of cell proliferation mediated by HBxΔ127 in vitro. Knockdown of PTPRT by siRNA could distinctly suppress the decrease of cell proliferation mediated by anti-miR-215 in HepG2-XΔ127/H7402-XΔ127 cells. Moreover, we found that anti-miR-215 remarkably inhibited the tumor growth of hepatoma cells in nude mice. Collectively, relative to wild type HBx, HBxΔ127 strongly enhances proliferation of hepatoma cells through up-regulating miR-215 targeting PTPRT. Our finding provides new insights into the mechanism of HBx mutant HBxΔ127 in promotion of proliferation of hepatoma cells.     

MiR-371-5p Facilitates Pancreatic Cancer Cell Proliferation and Decreases Patient Survival

Background

microRNAs (miRNAs) play a critical role in tumorigenesis, either as a tumor suppressor or as an oncogenic miRNA, depending on different tumor types. To date, scientists have obtained a substantial amount of knowledge with regard to miRNAs in pancreatic cancer. However, the expression and function of miR-371-5p in pancreatic cancer has not been clearly elucidated. The aim of this study was to investigate the roles of miR-371-5p in pancreatic cancer and its association with the survival of patients with pancreatic cancer.

Methods

The expression of miR-371-5p was examined in pancreatic duct adenocarcinoma (PDAC) and their adjacent normal pancreatic tissues (ANPT) or in pancreatic cancer cell lines by qRT-PCR. The association of miR-371-5p expression with overall survival was determined. The proliferation and apoptosis of SW-1990 and Panc-1 cells, transfected with miR-371-5p mimics or inhibitor, were assessed using MTT assay and flow cytometry, respectively. The tumorigenicity was evaluated via mice xenograft experiments. miR-371-5p promoter interactions were analyzed by chromatin immunoprecipitation assays (ChIP). Protein expression was analyzed by Western blot.

Results

The expression level of miR-371-5p was dramatically upregulated in clinical PDAC tissues compared with ANPT. Patients with high miR-371-5p expression had a significantly shorter survival than those with low miR-371-5p expression. The in vitro and in vivo assays showed that overexpression of miR-371-5p resulted in cell proliferation and increased tumor growth, which was associated with inhibitor of growth 1 (ING1) downregulation. Interestingly, we also found that ING1, in turn, inhibited expression of miR-371-5p in the promoter region.

Conclusions

our study demonstrates a novel ING1-miR-371-5p regulatory feedback loop, which may have a critical role in PDAC. Thus miR-371-5p can prove to be a novel prognostic factor and therapeutic target for pancreatic cancer treatment.     

miR-183-5p functions as a tumor suppressor in lung cancer through PIK3CA inhibition

Background

Lung cancer is the leading cause of cancer-related death worldwide. Previous studies revealed that miR-183-5p is frequently involved in various human cancers. However, the exact role of miR-183-5p in regulating the pathogenesis of lung cancer remains unclear.