406893

MIR101-1

Ovarian carcinoma is the most lethal gynecologic malignancy; the majority of patients succumb to the disease within 5 years of diagnosis. The poor survival rate is attributed to diagnosis at advanced stage, when the tumor has metastasized. The epithelial-to-mesenchymal transition (EMT) is a necessary step toward metastatic tumor progression. Through integrated computational analysis, we recently identified a master microRNA (miRNA) network that includes miR-101 and regulates EMT in ovarian carcinoma. In the present study, we characterized the functions of miR-101. Using reporter gene assays, we demonstrated that miR-101 suppressed the expression of the E-cadherin repressors ZEB1 and ZEB2 by directly targeting the 3'-untranslated region (3'UTR) of both ZEB1 and ZEB2. Introduction of miR-101 significantly inhibited EMT and cell migration and invasion. Introducing cDNAs of ZEB1 and ZEB2 without 3'UTR abrogated miR-101-induced EMT alteration, respectively. Our findings showed that miR-101 represents a redundant mechanism for the miR-200 family that regulates EMT through two major E-cadherin transcriptional repressors.

miR-101 is an outstanding tumor suppressor in various cancers, while its role in pancreatic cancer (PC) is still unknown. The aim of this study was to investigate the role of miR-101 in epithelial-to-mesenchymal transition (EMT) and its clinical relevance in PC. Our data showed that the miR-101 expression was significantly decreased in human PC tissues, compared to non-tumor counterparts (p<0.05), which was reversely correlated to clinical characteristics, including lymph node metastasis, more venous infiltration, higher expression of CA19-9 and TNM stage (p<0.05). Low miR-101 expression was also confirmed to be associated with a poorer overall survival rate in PC patients (p<0.05). We identified high-mobility group AT-hook 2 (HMGA2) gene as a putative target of miR-101 in PC by bioinformatics analysis, dual luciferase activity and western blot assay, and found that miR-101 could specifically target the HMGA2 3'-untranslated region (3'-UTR) (p<0.05). Knockdown of HMGA2 reversed EMT resembling that of miR-101 over-expression. An inverse correlation between miR-101 and HMGA2 was observed in patients with PC (p<0.05). Taken together, our findings speculated that miR-101 might act as an inhibiting factor in EMT process in PC and up-regulation of miR-101 might be considered as a potentially key molecular treatment strategy for PC patients.

Gallbladder cancer (GBC), the most common malignancy of the bile duct, is highly aggressive and has an extremely poor prognosis, which is a result of early metastasis. As it is regulated being at multiple levels, the metastatic cascade in GBC is complex. Recent evidence suggests that microRNAs (miRNAs) are involved in cancer metastasis and are promising therapeutic targets. In this study, miR-101 was significantly downregulated in tumor tissues, particularly in metastatic tissues. In GBC patients, low miR-101 expression was correlated with tumor size, tumor invasion, lymph node metastasis, TNM stage, and poor survival. Moreover, miR-101 was an independent prognostic marker for GBC. Additionally, miR-101 inhibited GBC cell proliferation, migration, invasion, and TGF-beta-induced epithelial-mesenchymal transition (EMT) in vitro and in vivo. Mechanistically, the gene encoding the zinc finger protein X-linked (ZFX) was identified as a direct target of miR-101. More importantly, miR-101 significantly reduced activation of the MAPK/Erk and Smad signaling pathways, resulting in inhibition of TGF-beta-mediated induction of EMT. Altogether, our findings demonstrate a novel mechanism by which miR-101 attenuates the EMT and metastasis in GBC cells and suggest that miR-101 can serve as a potential biomarker and therapeutic target for GBC management.

Hypoxia is a universal characteristic of solid tumor and involving cancer metastasis via epithelial-mesenchymal transition (EMT). Long non-coding RNAs (lncRNAs) are known to regulate carcinogenesis and metastasis of various cancers. The aim of this study was to identify the function role of lncRNAs in the hypoxia-induced EMT of malignant glioma. We used U87 and U251 cell lines were treated under hypoxia to induce EMT, then lncRNA microarray analyse was performed between U87-hypoxia and parental cell line. The relative expression of lncRNA and HIF-1alpha were detected by qRT-PCR between glioma tissues without metastasis and that with metastasis. Hypoxia could induce EMT and increase HOTTIP expression in glioma cells. Among the different expressions of lncRNAs, HOTTIP was the most upregulated lncRNA in glioma cells treated by hypoxia. High levels of HOTTIP and HIF-1alpha were correlated with glioma metastasis and poor patient prognosis. Knockdown of HIF-1alpha and HOTTIP blocked hypoxia-induced EMT, and suppressed invasion and migration of glioma cells. Finally, HOTTIP sponged endogenous miR-101 and inhibited its activity, which resulted in increased ZEB1 expression and promoted process of EMT. HIF-1alpha/HOTTIP/miR-101/ZEB1 axis plays essential role in hypoxia-induced EMT and metastasis of glioma, and HOTTIP may serve as a therapeutic target to reverse EMT and prevent glioma progression.CI - Copyright (c) 2017. Published by Elsevier Masson SAS.

BACKGROUND: Ovarian cancer (OvCa) is one of the most common malignant diseases of the female reproductive system in the world. The majority of OvCa is diagnosed with metastasis in the abdominal cavity. epithelial-to-mesenchymal transition (EMT) plays a key role in tumor cell metastasis. However, it is still unclear whether long non-coding RNA (lncRNA) is implicated in EMT and influences cell invasion and metastasis in OvCa. RESULTS: In this study, using bioinformatcis analysis, we constructed a lncRNA-mediated competing endogenous RNA (ceRNA) network for mesenchymal OvCa and identified lncRNA AP000695.4, which we named pro-transition associated RNA (PTAR). PTAR was significantly up-regulated in the mesenchymal subtype samples compared with the epithelial subtype samples from the TCGA OvCa data sets. In addition, our study showed that PTAR expression was positively correlated with the expression level of ZEB1 in the mesenchymal OvCa samples. Meanwhile, we found that silencing miR-101 promoted cell migration, whereas the overexpression of miR-101 suppressed EMT and cell migration in OvCa cell lines through the regulation of ZEB1. Further analysis showed that enhanced expression of PTAR promoted EMT and metastasis through the regulation of miR-101, whereas silencing PTAR led to the attenuation of TGF-beta1-induced tumorigenicity in ovarian cancer cells. Mechanistically, we found that PTAR acted as a ceRNA of miR-101, as forced expression of PTAR reduced the expression and activity of miR-101. More importantly, the knockdown of PTAR reduced tumorigenicity and metastasis in vivo. CONCLUSIONS: Taken together, the results from our study highlight a role for the PTAR-miR-101-ZEB1 axis in OvCa, which offers novel strategies for the prevention of metastasis in OvCa.