MicroRNA-29a promotes colorectal cancer metastasis by regulating matrix metalloproteinase 2 and E-cadherin via KLF4

Background:

Growing evidence suggests that miR-29a has an important role in regulating tumourigenesis and development of various types of cancer. However, the role and the underlying mechanism of miR-29a in colorectal cancer (CRC) remain largely unknown.

Methods:

MiR-29a targeted gene was identified by the luciferase assay and western blot. MiR-29a function was analysed by invasion assays and the orthotopic transplantation mouse model. The miR-29a pathway was assayed by real-time PCR, western blot and chip analysis.

Results:

KLF4 was identified as a direct target gene of miR-29a. MiR-29a promoted CRC cell invasion, which was blocked by re-expression of KLF4. In addition, MMP2 was identified as a novel direct target of KLF4. Both miR-29a overexpression and KLF4 knockdown promoted MMP2 expression but inhibited E-cadherin expression. Furthermore, clinical data indicated that both miR-29a high expression and KLF4 mRNA low expression were associated with metastasis and poor prognosis in CRC patients, and KLF4 protein expression was inversely correlated with MMP2 but positively correlated with E-cad protein expression.

Conclusion:

Increased expression of miR-29a promoted CRC metastasis by regulating MMP2/E-cad through direct targeting KLF4, which highlights the potential of the miR-29a inhibitor as a novel agent against CRC metastasis.     

MicroRNA-155 promotes bladder cancer growth by repressing the tumor suppressor DMTF1

MicroRNA-155 (miR-155) is dysregulated in human cancers. In this study, we reported that miR-155 was over-expressed in bladder cancer tissues. We found that miR-155 promoted cell proliferation in vitro and tumorigenesis in vivo. MiR-155 directly reduced the expression of the tumor suppressor DMTF1. The expression of DMTF1 was decreased in bladder cancer tissues. Similar to the restoring miR-155 expression, knockdown of DMTF1 promoted cell growth and cell cycle progression, whereas DMTF1 over-expression rescued the effect of miR-155. Moreover, we investigated DMTF1-Arf-p53 pathway and found that DMTF1 worked in both p53-dependent and p53-independent manners. Taken together, our findings suggested that miR-155 functions as a tumor promoter in bladder cancer, which is partially through repressing DMTF1 expression. The identification of miR-155 and its novel target DMTF1 will be valuable in developing diagnostic markers and therapeutic applications for bladder cancer.     

MicroRNA-1 acts as a tumor suppressor microRNA by inhibiting angiogenesis-related growth factors in human gastric cancer

Background

We recently reported that miR-1 was one of the most significantly downregulated microRNAs in gastric cancer (GC) patients from The Cancer Genome Atlas microRNA sequencing data. Here we aim to elucidate the role of miR-1 in gastric carcinogenesis.

Methods

We measured miR-1 expression in human GC cell lines and 90 paired primary GC samples, and analyzed the association of its status with clinicopathological features. The effect of miR-1 on GC cells was evaluated by proliferation and migration assay. To identify the target genes of miR-1, bioinformatic analysis and protein array analysis were performed. Moreover, the regulation mechanism of miR-1 with regard to these predicted targets was investigated by quantitative PCR (qPCR), Western blot, ELISA, and endothelial cell tube formation. The putative binding site of miR-1 on target genes was assessed by a reporter assay.

Results

Expression of miR-1 was obviously decreased in GC cell lines and primary tissues. Patients with low miR-1 expression had significantly shorter overall survival compared with those with high miR-1 expression (P = 0.0027). Overexpression of miR-1 in GC cells inhibited proliferation, migration, and tube formation of endothelial cells by suppressing expression of vascular endothelial growth factor A (VEGF-A) and endothelin 1 (EDN1). Conversely, inhibition of miR-1 with use of antago-miR-1 caused an increase in expression of VEGF-A and EDN1 in nonmalignant GC cells or low-malignancy GC cells.

Conclusions

MiR-1 acts as a tumor suppressor by inhibiting angiogenesis-related growth factors in human gastric cancer. Downregulated miR-1 not only promotes cellular proliferation and migration of GC cells, but may activates proangiogenesis signaling and stimulates the proliferation and migration of endothelial cells, indicating the possibility of new strategies for GC therapy.

     

MicroRNA-148b is frequently down-regulated in gastric cancer and acts as a tumor suppressor by inhibiting cell proliferation

Background  

MicroRNAs (miRNAs) are involved in cancer development and progression, acting as tumor suppressors or oncogenes. Our previous studies have revealed that miR-148a and miR-152 are significantly down-regulated in gastrointestinal cancers. Interestingly, miR-148b has the same "seed sequences" as miR-148a and miR-152. Although aberrant expression of miR-148b has been observed in several types of cancer, its pathophysiologic role and relevance to tumorigenesis are still largely unknown. The purpose of this study was to elucidate the molecular mechanisms by which miR-148b acts as a tumor suppressor in gastric cancer.     

miR-133b acts as a tumor suppressor and negatively regulates FGFR1 in gastric cancer

MicroRNAs (miRNAs) are a class of small noncoding RNAs that negatively regulate protein expression by binding protein-coding mRNAs and repressing translation. Accumulating evidence suggests that miRNAs are involved in cancer development and progression, acting as either tumor suppressors or oncogenes. Intriguingly, it has been shown that miR-133b was significantly downregulated in several types of cancers. However, its role and relevance in gastric cancer are still largely unknown. We showed that miR-133b was downregulated in human gastric cancer tissues and cell lines compared with nontumor counterparts by quantitative RT-PCR analysis. Overexpression of miR-133b could inhibit cell proliferation and colony formation of the gastric cancer cell lines MKN-45 and SGC-7901. Bioinformatics analysis indicated two putative miR-133b binding sites in the 3′-untranslated region of fibroblast growth factor receptor 1 (FGFR1) mRNA. In dual-luciferase reporter assay, miR-133b reduced the luciferase activity of Luc-FGFR1-wt, and mutation of miR-133b binding sites abolished the inhibitory effect of miR-133b. In this study, we found that miR-133b reduced the protein but not the mRNA levels of endogenous FGFR1. Furthermore, FGFR1 expression was upregulated in gastric cancer tissues and inversely correlated with miR-133b expression. Finally, knockdown of FGFR1 inhibited the growth of MKN-45 cells in a dose-dependent manner and overexpression of FGFR1 promoted the growth of GES-1 cells. These results indicate that miR-133b targets FGFR1 and inhibits gastric cancer cell growth, suggesting that it may serve as a tumor suppressive target in gastric cancer therapy.     

MicroRNA-146a acts as a metastasis suppressor in gastric cancer by targeting WASF2

Previous studies have shown that miR-146a acts as either an oncogene or a tumor suppressor in various cancers. In this study, we investigated the role of miR-146a in gastric cancer cells and its potential target genes. The results showed that miR-146a expression correlated inversely with WASF2 protein expression in gastric cancer cell lines. Overexpression of miR-146a suppressed the migration and invasion of gastric cancer cells, and also the protein level of WASF2. WASF2 was shown to be a direct target gene of miR-146a by luciferase assays. Restoration of WASF2 promoted the migration and invasion of gastric cancer cells, similar to that mediated by miR-146a inhibition. This study has identified an onco-suppressive role of miR-146a in gastric cancer cells by its reduction of WASF2 expression. The newly identified miR-146a/WASF2 axis partially reveals the molecular mechanism underlying the migration and invasion of gastric cancer cells and represents a new potential therapeutic target for gastric cancer.     

UHRF1 promotes proliferation of gastric cancer via mediating tumor suppressor gene hypermethylation

Epigenetic changes play significant roles in cancer development. UHRF1, an epigenetic regulator, has been shown to be overexpressed and to coordinate tumor suppressor gene (TSG) silencing in several cancers. In a previous study, we found that UHRF1 promoted gastric cancer (GC) invasion and metastasis. However, the role and underlying mechanism of UHRF1 in GC carcinogenesis remain largely unknown. In the present study, we investigated UHRF1 expression and function in GC proliferation and explored its downstream regulatory mechanism. The results demonstrated that UHRF1 overexpression was an independent and significant predictor of GC prognosis. Downregulation of UHRF1 suppressed GC proliferation and growth in vitro and in vivo, and UHRF1 upregulation showed opposite effects. Furthermore, downregulation of UHRF1 reactivated 7 TSGs, including CDX2, CDKN2A, RUNX3, FOXO4, PPARG, BRCA1 and PML, via promoter demethylation. These results provide insight into the GC proliferation process, and suggest that targeting UHRF1 represents a new therapeutic approach to block GC development.     

三氧化二砷负向调控MDSC的肿瘤免疫抑制功能

目的:研究三氧化二砷(arsenic trioxide,As2O3)是否通过抑制髓系来源抑制性细胞(myeloid-derived suppressor cells,MDSCs)负向调控MDSCs诱导的肿瘤免疫耐受作用.方法:C57BL/6小鼠皮下注射黑素瘤B16细胞和肝癌H22细胞构建移植瘤模型,As2O3处理,观察移植瘤生长情况,流式细胞术检测荷瘤小鼠脾脏内MDSCs和其他免疫细胞的免疫表型,流式细胞术检测2 μmol/L As2O3对B16模型小鼠来源的MDSCs分化的影响.取B16模型小鼠随机分为As2O3处理及对照组,混合淋巴细胞反应检测MDSCs对T细胞免疫抑制活性的改变,ELISA检测B16模型小鼠血清及MDSCs培养上清中TNF-α、IL-10的水平.结果:As2O3抑制B16和H22模型鼠的肿瘤生长,延长B16模型小鼠的生存期,并可显著下调小鼠脾脏内MDSCs的比例.体外经2 μmol/L As2O3处理5d后,B16模型小鼠来源的MDSCs中成熟DCs(CD11c+ CD40+)的比例较对照组显著升高[(27.38±4.57)％ vs (17.44±4.51)％,P=0.0078];As2O3组来源的MDSCs对T细胞的免疫抑制活性明显低于对照组(P =0.016);As2O3组小鼠血清及MDSCs培养上清中TNF-α(F=5.78,P=0.014)和IL-10(F=17.83,P=0.045)的含量均较对照组显著降低.结论:As2O3可通过诱导MDSCs向成熟表型分化、下调其免疫抑制活性等,负调控MDSCs的肿瘤免疫抑制功能.     

MicroRNA-143 acts as a tumor suppressor by targeting hexokinase 2 in human prostate cancer

MicroRNAs (miRNAs) are small non-coding RNAs that play important roles in cancer progression through regulating gene expression. Down-regulation of miR-143 has been reported in a number of cancers. However, the biological functions of miR-143 in prostate cancer remain largely unexplored. In this study, we showed that miR-143 expression was reduced in approximately 62.5% of the specimens examined. By loss-of-function and gain-of-function studies in human prostate cancer PC-3 cells, we demonstrated that miR-143 has an inhibitory effect on cell proliferation as evidenced by decreased cell viability, increased cell apoptosis and cell cycle arrest at the G1/S transition. Furthermore, we identified hexokinase 2 (HK2), a metabolic enzyme that executes the first step of aerobic glycolysis, as a target of miR-143 in prostate cancer. Knockdown of HK2 recapitulated the effects of miR-143 and accompanied with decreased glucose metabolism. Taken together, these data indicate that miR-143/HK2 axis plays an important role in the development of prostate cancer and represents a potential therapeutic target for prostate cancer.     

MicroRNA-25 functions as a potential tumor suppressor in colon cancer by targeting Smad7

Because it is a member of the miR-106b∼25 cluster, microRNA-25 (miR-25) is known to be dysregulated in human cancers. However, the expression and role of miR-25 in colon cancer remain unclear. In this study, miR-25 was found to be down-regulated in human colon cancer tissues when compared to those in matched, non-neoplastic mucosa tissues. Functional studies revealed that restoration of miR-25 expression inhibited cell proliferation and migration. In contrast, miR-25 inhibition could promote the proliferation and migratory ability of cells. Stable over-expression of miR-25 also suppressed the growth of colon cancer-cell xenografts in vivo. Furthermore, bioinformatic predictions and experimental validation were used to identify Smad7 as a direct target of miR-25. Functional reverse experiments indicated that the antitumor effects of miR-25 were probably mediated by its repression of Smad7. These results suggest that miR-25 may function as a tumor suppressor by targeting Smad7 in colon cancer. Thus, miR-25 may serve as a potential therapeutic agent or target for cancer therapy.     

MicroRNA-10a通过调控MMP的表达促进胶质瘤细胞侵袭

目的:研究microRNA-10a( miR-10a)对人脑胶质瘤细胞系U87MG侵袭性的影响.方法:脂质体包被miR-10a反义寡聚核苷酸(miR-10a antisense oligodeoxynucleotide,miR-10a-anti-ODN),转染胶质瘤U87MG细胞,并设无义miRNA转染组和空白对照组,...     

The OPCML tumor suppressor functions as a cell surface repressor-adaptor, negatively regulating receptor tyrosine kinases in epithelial ovarian cancer

Epithelial ovarian cancer is the leading cause of death from gynecologic malignancy, and its molecular basis is poorly understood. We previously demonstrated that opioid binding protein cell adhesion molecule (OPCML) was frequently epigenetically inactivated in epithelial ovarian cancers, with tumor suppressor function in vitro and in vivo. Here, we further show the clinical relevance of OPCML and demonstrate that OPCML functions by a novel mechanism in epithelial ovarian cancer cell lines and normal ovarian surface epithelial cells by regulating a specific repertoire of receptor tyrosine kinases: EPHA2, FGFR1, FGFR3, HER2, and HER4. OPCML negatively regulates receptor tyrosine kinases by binding their extracellular domains, altering trafficking via nonclathrin-dependent endocytosis, and promoting their degradation via a polyubiquitination-associated proteasomal mechanism leading to signaling and growth inhibition. Exogenous recombinant OPCML domain 1-3 protein inhibited the cell growth of epithelial ovarian cancers cell in vitro and in vivo in 2 murine ovarian cancer intraperitoneal models that used an identical mechanism. These findings demonstrate a novel mechanism of OPCML-mediated tumor suppression and provide a proof-of-concept for recombinant OPCML protein therapy in epithelial ovarian cancers. SIGNIFICANCE: The OPCML tumor suppressor negatively regulates a specific spectrum of receptor tyrosine kinases in ovarian cancer cells by binding to their extracellular domain and altering trafficking to a nonclathrin, caveolin-1–associated endosomal pathway that results in receptor tyrosine kinase polyubiquitination and proteasomal degradation. Recombinant OPCML domain 1-3 recapitulates this mechanism and may allow for the implementation of an extracellular tumor-suppressor replacement strategy.