100124700

HOTAIR

Hotair is a member of the recently described class of noncoding RNAs called lincRNA (large intergenic noncoding RNA). Various studies suggest that Hotair acts regulating epigenetic states by recruiting chromatin-modifying complexes to specific target sequences that ultimately leads to suppression of several genes. Although Hotair has been associated with metastasis and poor prognosis in different tumor types, a deep characterization of its functions in cancer is still needed. Here, we investigated the role of Hotair in the scenario of epithelial-to-mesenchymal transition (EMT) and in the arising and maintenance of cancer stem cells (CSCs). We found that treatment with TGF-beta1 resulted in increased Hotair expression and triggered the EMT program. Interestingly, ablation of Hotair expression by siRNA prevented the EMT program stimulated by TGF-beta1, and also the colony-forming capacity of colon and breast cancer cells. Furthermore, we observed that the colon CSC subpopulation (CD133(+)/CD44(+)) presents much higher levels of Hotair when compared with the non-stem cell subpopulation. These results indicate that Hotair acts as a key regulator that controls the multiple signaling mechanisms involved in EMT. Altogether, our data suggest that the role of Hotair in tumorigenesis occurs through EMT triggering and stemness acquisition.CI - (c) AlphaMed Press.

epithelial-mesenchymal transition (EMT) contributes to tumor invasion and metastasis in many cancers and correlates highly with the acquisition of cancer stem cell (CSC) characteristics. EMT also correlates with changes in specific microRNAs (miRNAs) that have already been integrated into tumorigenic programs as either oncogenes or tumor suppressor genes. Here, we show that miR-7, which was downregulated in breast CSCs (BCSCs) isolated from the human MCF-7 and MDA-MB-231 cell lines, inhibited cell invasion and metastasis, decreased the BCSC population and partially reversed EMT in MDA-MB-231 cells by directly targeting the oncogene, SETDB1. The conspicuous epigenetic transition induced by miR-7 overexpression was found not only in MDA-MB-231 cells but also in BCSC xenograft tumors. MiR-7 inhibited the metastasis of BCSCs in lungs, kidneys, and adrenal glands of NOD/SCID mice. ChIP-polymerase chain reaction result suggested that the SETDB1 induced STAT3 expression by binding to the promoter of STAT3. MiR-7-mediated downregulation of SETDB1 resulted in the suppression of STAT3, which led to the downregulation of c-myc, twist, and mir-9. In addition, the downregulation of miR-7 in BCSCs may be indirectly attributed to lincRNA HOTAIR by modulating the expression of HoxD10 that promotes the expression of miR-7. These findings demonstrate that miR-7 was a tumor suppressor and that the overexpression of miR-7 might serve as a good strategy for treating highly invasive breast cancer.CI - (c) 2014 AlphaMed Press.

lncRNAs play important roles in the epigenetic regulation of carcinogenesis and progression. Previous studies suggest that HOTAIR contributes to gastric cancer (GC) development, and the overexpression of HOTAIR predicts a poor prognosis. In this study, we found that HOTAIR was more highly expressed in diffuse-type GC than in intestinal type (P=0.048). In the diffuse type, there is significant relationship between HOTAIR expression and DFS (P<0.001). CDH1 was downregulated in diffuse-type GC tissues (P=0.0007) and showed a negative relationship with HOTAIR (r(2)=0.154, P=0.0354). In addition, HOTAIR knockdown significantly repressed migration, invasion and metastasis both in vitro and vivo and reversed the epithelial-to-mesenchymal transition in GC cells. We also showed that HOTAIR recruiting and binding to PRC2 epigenetically represses miR34a, which controls the targets C-Met (HGF/C-Met/Snail pathway) and Snail, thus contributing to GC cell-EMT process and accelerating tumor metastasis. Moreover, it is demonstrated that HOTAIR crosstalk with microRNAs during epigenetic regulation. Our results suggest that HOTAIR acts as an EMT regulator and may be a candidate prognostic biomarker and a target for new therapies in GC patients.

BACKGROUND: Endometrial cancer (EC) is a hormone-related disease, showing highly diverse features of ER/PR/HER2 status-based molecular subtypes. Long noncoding RNA (lncRNA) HOX antisense intergenic RNA (HOTAIR) has recently emerged as a key molecule in many cancers, triggering epithelial-mesenchymal transition (EMT)-mediated cancer stem cell (CSC) formation, but little is known about its significance in EC. Thus, we aimed to investigate the clinical significance of HOTAIR itself in different molecular subtypes of EC and possible links between HOTAIR, EMT and CSC-related markers. METHODS: The study group included 156 consecutive, stage I-IV EC patients treated between 2000 and 2010. ER, PR and HER2 protein expression were examined by immunohistochemistry (IHC) on tissue microarrays. RT-qPCR was used to analyze the expression levels of HOTAIR, EMT-related genes - SNAIL and SLUG - and the CSCs marker CD133. RESULTS: Molecular subtypes, defined as ER/PR+HER2+, ER/PR+HER2-, ER-PR-HER2+ and ER-PR-HER2-, occurred in 40.2%, 52.3%, 4.7% and 1.9% of cases, respectively. The expression of HOTAIR did not differ between the subtypes, but high HOTAIR expression correlated with shorter overall survival (p = 0.04) in the entire group. The expression levels of HOTAIR, SNAIL, SLUG and CD133 were similar in defined EC molecular subtypes. CONCLUSIONS: Our data do not confirm the role of HOTAIR in EMT-mediated CSC formation in EC. Neither does the diversity of EC molecular subtypes influence these processes. But HOTAIR expression could serve as an independent prognostic factor in EC. The clinical importance of the above discoveries requires further studies.

Evidence suggests that the long non-coding RNA (lncRNA), HOTAIR, is involved in cervical cancer pathogenesis. We examined serum HOTAIR expression levels in cervical cancer patients and determined the relationships between HOTAIR expression and several clinicopathological factors, including survival. We also examined the functional consequences of HOTAIR overexpression both in vitro and in vivo. Compared with control patients, HOTAIR expression was significantly greater in the serum of cervical cancer patients (P < 0.001). The results indicated that this increase was significantly associated with tumour size (P = 0.030), lymphovascular space invasion (P = 0.037), and lymph node metastasis (P = 0.043). Univariate analysis revealed that disease-free survival and overall survival times were significantly shorter in cervical cancer patients with high HOTAIR expression (hazard ratio [HR] = 4.27, 4.68 and P = 0.039, 0.031, respectively). Cell proliferation and invasion in vitro increased as a result of lentiviral-mediated HOTAIR overexpression in cervical cancer cell lines. HOTAIR knockdown inhibited these properties and increased apoptosis. In vivo xenograft experiments using the HOTAIR-overexpressing SiHa cell line revealed that HOTAIR was a strong inducer of tumour growth and modulated the expression of epithelial-mesenchymal transition and Notch-Wnt signalling pathway-related genes. This result suggested that HOTAIR overexpression promoted cell proliferation and invasion. In conclusion, increased HOTAIR expression was associated with decreased patient survival times. HOTAIR may be a useful target for treatment of cervical cancer patients.

Hepatocellular carcinoma (HCC) is the fifth most common cancer around the world, along with high mortality and metastasis rate. Our present study aimed to explore the role of LncRNA HOTAIR in the progression of HCC. Our data showed that HOTAIR was overexpressed in HCC tissues and cell lines (Huh7, Hep3B, HepG2, MHCC97H). Overexpressed HOTAIR promoted invasion and migration of HCC cells (Huh7) by enhancing epithelial-mesenchymal transition (EMT). Besides that, miR-23b-3p was predicted to be a target of HOTAIR and decreased expression of miR-23b-3p was observed in HCC tissues and cell lines. The up-regulation of HOTAIR strongly decreased the expression of miR-23b-3p. The further luciferase report confirmed the targeting reaction between HOTAIR and miR-23b-3p, suggesting that the expression of miR-23b-3p was negatively regulated by HOTAIR. Moreover, the zinc-finger E-box-binding homeobox 1 (ZEB1) protein was predicted to be a target of miR-23b-3p. The expression of ZEB1 was negatively regulated by miR-23b-3p while positively regulated by HOTAIR. Besides that, transfection with miR-23b-3p mimic counteracted the promoting effects of HOTAIR on invasion, migration and EMT of HCC cells. Our in vitro experiments suggested that HOTAIR promoted invasion and migration of HCC cells through enhancing EMT via sponging miR-23b-3p from ZEB1. Finally, the in vivo experiments indicated that HOTAIR could promote metastasis of HCC by enhancing EMT in vivo. Taken together, our study demonstrated that the HOTAIR-miR-23b-3p-ZEB1 axis may provide a new perspective for treatment of HCC.CI - Copyright (c) 2018 Elsevier B.V. All rights reserved.

Dysregulation of the cell cycle is a key indicator of tumors, including lung cancer. Recently, the study of cell cycle inhibitors has made great progress in relation to lung cancer. However, the question of what kinds of patients can use cell cycle inhibitors has plagued us. Therefore, seeking an accurate and convenient marker for the abnormal cell cycle in lung cancer is very important. In the present research, we showed that lncRNA HOTAIR is an optimal indicator of cell cycle dysregulation in lung cancer. In the present study, we investigated HOTAIR-specific expression in lung primary tumor samples by analyzing the TCGA public database and 67 pairs of patients' tissues collected from our department. Through the TCGA public database KEGG analysis, HOTAIR correlates with the cell cycle pathway. We identified that HOTAIR and its 2 segments, HOTAIR3' and HOTAIR5', promote the cell cycle passing through the restriction point during G1-S phase by regulating the Rb-E2F pathway and influence non-small-cell lung cancer cell proliferation, migration and invasion through epithelial-mesenchymal transition (EMT) and the beta-catenin pathway in vitro and vivo. Finally, we showed that the high expression of HOTAIR was associated with resistance to gefitinib through the dysregulated cell cycle. In conclusion, HOTAIR could be an ideal indicator of cell cycle dysregulation and guide the use of cell cycle inhibitors.CI - (c) 2018 The Authors. cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese cancer Association.

Posterior capsule opacification (PCO) results from the proliferation, migration, and epithelial-mesenchymal transition (EMT) of residual lens epithelial cells (LECs) and fibers in the capsular bag. Previous reports have demonstrated that transforming growth factor beta2 (TGF-beta2) affects the cellular processes via modulation of EMT in LECs. However, the mechanisms that underlie the TGF-beta2-induced EMT in LECs are still largely unknown. In this study, we confirmed that TGF-beta2 induces EMT in SRA01/04 cells via the up-regulation of the long non-coding RNA (lncRNA) HOTAIR. To study the effects of HOTAIR on the proliferation, migration and EMT of SRA01/04 cells as well as the underlying mechanism, we used small interfering RNA (siRNA) to specifically attenuate HOTAIR expression in SRA01/04 cells. CCK8 cell-counting kit was used to examine SRA01/04 cell viability; EdU cell proliferation kit was used to examine SRA01/04 cell proliferation; Transwell system and scratch assays were used to observe cell migration; and qPCR and western blot analysis were used to evaluate EMT progression. We found that inhibition of HOTAIR expression repressed SRA01/04 cell viability, proliferation, migration and prevented the TGF-beta2-induced changes in cellular processes via modulation of EMT. Ultimately, we found that HOTAIR affected the TGF-beta/Smad signaling pathway. In summary, we elucidated that HOTAIR affected the cell viability, proliferation, and migration in the TGF-beta2-induced EMT in SRA01/04 cells and suggested that modulation of HOTAIR may be helpful in PCO prevention and therapy.