Overexpression of ZEB2‐AS1 promotes epithelial‐to‐mesenchymal transition and metastasis by stabilizing ZEB2 mRNA in head neck squamous cell carcinoma

The long noncoding RNAs (lncRNAs) have been increasingly appreciated as key players underlying tumourigenesis and hold great potentials as prognostic biomarkers and therapeutic targets. However, their roles in head neck squamous cell carcinoma (HNSCC) have remained incompletely known. Here, we sought to reveal the oncogenic roles and clinical significance of a tumour‐associated lncRNA, zinc finger E‐box binding homeobox 2 antisense RNA 1 (ZEB2‐AS1), in HNSCC. ZEB2‐AS1 was aberrantly overexpressed in a fraction of HNSCC samples. Its overexpression significantly associated with large tumour size, cervical node metastasis and reduced overall and disease‐free survival. Antisense oligonucleotides (ASO)‐mediated ZEB2‐AS1 depletion markedly inhibited cell proliferation, migration and invasion while triggered apoptosis in HNSCC cells in part via modulating ZEB2 mRNA stability. Enforced overexpression of ZEB2 largely attenuated the phenotypic changes resulted from ZEB2‐AS1 inhibition except the impaired cell proliferation. In addition, ZEB2‐AS1 was required for TGF‐β1‐induced epithelial‐mesenchymal transition (EMT) in vitro. Significantly reduced tumour growth and lung metastasis were observed in ZEB2‐AS1‐depleted cells in HNSCC xenograft animal models. Taken together, our findings reveal that overexpression of ZEB2‐AS1 associates with tumour aggressiveness and unfavourable prognosis by serving as a putative oncogenic lncRNA and a novel prognostic biomarker in HNSCC.     

Down‐regulated lncRNA SBF2‐AS1 in M2 macrophage‐derived exosomes elevates miR‐122‐5p to restrict XIAP,thereby limiting pancreatic cancer development

Evidence has indicated that M2 macrophages promote the progression of cancers, but few focus on the ability of M2 macrophage‐derived exosomes in pancreatic cancer (PC). This study aims to explore how M2 macrophages affect malignant phenotypes of PC through regulating long non‐coding RNA SET‐binding factor 2 antisense RNA 1 (lncRNA SBF2‐AS1)/microRNA‐122‐5p (miR‐122‐5p)/X‐linked inhibitor of apoptosis protein (XIAP) axis. THP‐1 cells were transformed into M1 macrophages by lipopolysaccharide and interferon‐γ treatment, and into M2 macrophages after interleukin‐4 treatment. The PANC‐1 PC cell line with the largest lncRNA SBF2‐AS1 expression was selected, and M2 macrophage‐derived exosomes were isolated and identified. A number of assays were applied for the examination of lncRNA SBF2‐AS1 expression, PC cell biological functions and subcellular localization of lncRNA SBF2‐AS1. XIAP expression was detected, along with the interaction among lncRNA SBF2‐AS1, miR‐122‐5p and XIAP. M2 macrophage exosomal lncRNA SBF2‐AS1 expression's effects on the tumorigenic ability of PANC‐1 cells in nude mice were also investigated. M2 macrophage‐derived exosomes promoted progression of PC cells. Overexpressed lncRNA SBF2‐AS1 promoted progression of PC cells. LncRNA SBF2‐AS1 was found to act as a competing endogenous RNA to repress miR‐122‐5p and up‐regulate XIAP. Constrained lncRNA SBF2‐AS1 in M2 macrophage‐derived exosomes contributed to restraining tumorigenic ability of PC cells. Collectively, our study reveals that constrained lncRNA SBF2‐AS1 in M2 macrophage‐derived exosomes increases miR‐122‐5p expression to restrain XIAP expression, which further inhibits PC progression.     

LncRNA ZEB1‐AS1 down‐regulation suppresses the proliferation and invasion by inhibiting ZEB1 expression in oesophageal squamous cell carcinoma

Multiple studies have unveiled that long non‐coding RNAs (lncRNAs) play a pivotal role in tumour progression and metastasis. However, the biological role of lncRNA ZEB1‐AS1 in oesophageal squamous cell carcinoma (ESCC) remains under investigation, and thus, the current study was to investigate the functions of ZEB1‐AS1 in proliferation and invasion of ESCC. Here, we discovered that ZEB1‐AS1 and ZEB1 were markedly up‐regulated in ESCC tissues and cells relative to their corresponding normal control. ZEB1‐AS1 and ZEB1 overexpressions were both related to TNM staging and lymph node metastasis as well as poor prognosis in ESCC. The hypomethylation of ZEB1‐AS1 promoter triggered ZEB1‐AS1 overexpression in ESCC tissues and cells. In addition, ZEB1‐AS1 knockdown mediated by siRNA markedly suppressed the proliferation and invasion in vitro in EC9706 and TE1 cells, which was similar with ZEB1 siRNA treatment, coupled with EMT alterations including the up‐regulation of E‐cadherin level as well as the down‐regulation of N‐cadherin and vimentin levels. Notably, ZEB1‐AS1 depletion dramatically down‐regulated ZEB1 expression in EC9706 and TE1 cells, and ZEB1 overexpression obviously reversed the inhibitory effects of proliferation and invasion triggered by ZEB1‐AS1 siRNA. ZEB1‐AS1 shRNA evidently inhibited tumour growth and weight, whereas ZEB1 elevation partly recovered the tumour growth in ESCC EC9706 and TE1 xenografted nude mice. In conclusion, ZEB1‐AS1 overexpression is tightly involved in the development and progression of ESCC, and it exerts the antitumour efficacy by regulating ZEB1 level in ESCC.     

Long non‐coding RNA FEZF1‐AS1 promotes breast cancer stemness and tumorigenesis via targeting miR‐30a/Nanog axis

Long non‐coding RNAs (lncRNAs) have been verified to modulate the tumorigenesis of breast cancer at multiple levels. In present study, we aim to investigate the role of lncRNA FEZF1‐AS1 on breast cancer‐stem like cells (BCSC) and the potential regulatory mechanism. In breast cancer tissue, lncRNA FEZF1‐AS1 was up‐regulated compared with controls and indicated poor prognosis of breast cancer patients. In vitro experiments, FEZF1‐AS1 was significantly over‐expressed in breast cancer cells, especially in sphere subpopulation compared with parental subpopulation. Loss‐of‐functional indicated that, in BCSC cells (MDA‐MB‐231 CSC, MCF‐7 CSC), FEZF1‐AS1 knockdown reduced the CD44⁺/CD24^? rate, the mammosphere‐forming ability, stem factors (Nanog, Oct4, SOX2), and inhibited the proliferation, migration and invasion. In vivo, FEZF1‐AS1 knockdown inhibited the breast cancer cells growth. Bioinformatics analysis tools and series of validation experiments confirmed that FEZF1‐AS1 modulated BCSC and Nanog expression through sponging miR‐30a, suggesting the regulation of FEZF1‐AS1/miR‐30a/Nanog. In summary, our study validate the important role of FEZF1‐AS1/miR‐30a/Nanog in breast cancer stemness and tumorigenesis, providing a novel insight and treatment strategy for breast cancer.     

LncRNA ABHD11‐AS1 promotes the development of endometrial carcinoma by targeting cyclin D1

To investigate the expression, role and mechanism of action of long non‐coding RNA (lncRNA) ABHD11‐AS1 in endometrial carcinoma. The expression of lncRNA ABHD11‐AS1 was quantified by qRT‐PCR in human endometrial carcinoma (n = 89) and normal endometrial tissues (n = 27). LncRNA ABHD11‐AS1 was stably overexpressed or knocked‐down in endometrial carcinoma cell lines to examine the cellular phenotype and expression of related molecules. Compared to normal endometrial tissue, lncRNA ABHD11‐AS1 was significantly overexpressed in endometrial carcinoma. Overexpression of lncRNA ABHD11‐AS1 promoted the proliferation, G1‐S progression, invasion and migration of endometrial cancer cells; inhibited apoptosis; up‐regulated cyclin D1, CDK1, CDK2, CDK4, Bcl‐xl and VEGFA; and down‐regulated p16, while ABHD11‐AS1 down‐regulation has the opposite effect. RNA pull down demonstrated that lncRNA ABHD11‐AS1 binds directly to cyclin D1. Knockdown of cyclin D1 can reverse the effect of ABHD11‐AS1. Overexpression of lncRNA ABHD11‐AS1 increased the tumorigenicity and up‐regulated cyclin D1 in an in vivo model of endometrial cancer in nude mice. LncRNA ABHD11‐AS1 functions as an oncogene to promote cell proliferation and invasion in endometrial carcinoma by positively targeting cyclin D1.     

lncRNA NR2F1‐AS1 promotes breast cancer angiogenesis through activating IGF‐1/IGF‐1R/ERK pathway

Long non‐coding RNAs (lncRNAs) take various effects in cancer mostly through sponging with microRNAs (miRNAs). lncRNA NR2F1‐AS1 is found to promote tumour progression in hepatocellular carcinoma, endometrial cancer and thyroid cancer. However, the role of lncRNA NR2F1‐AS1 in breast cancer angiogenesis remains unknown. In this study, we found lncRNA NR2F1‐AS1 was positively related with CD31 and CD34 in breast cancer through Pearson's correlation analysis, while lncRNA NR2F1‐AS1 transfection promoted human umbilical vascular endothelial cell (HUVEC) tube formation. In breast cancer cells, lncRNA NR2F1‐AS1 enhanced the HUVEC proliferation, tube formation and migration ability through tumour‐conditioned medium (TCM). In zebrafish model, lncRNA NR2F1‐AS1 increased the breast cancer cell‐related neo‐vasculature and subsequently promoted the breast cancer cell metastasis. In mouse model, lncRNA NR2F1‐AS1 promoted the tumour vessel formation, increased the micro vessel density (MVD) and then induced the growth of primary tumour. Mechanically, lncRNA NR2F1‐AS1 increased insulin‐like growth factor‐1 (IGF‐1) expression through sponging miRNA‐338‐3p in breast cancer cells and then activated the receptor of IGF‐1 (IGF‐1R) and extracellular signal‐regulated kinase (ERK) pathway in HUVECs. These results indicated that lncRNA NR2F1‐AS1 could promote breast cancer angiogenesis through IGF‐1/IGF‐1R/ERK pathway.     

Curcumin inhibits the growth of triple‐negative breast cancer cells by silencing EZH2 and restoring DLC1 expression

Enhancer of zeste homolog 2 (EZH2), an oncogene, is a commonly up‐regulated epigenetic factor in human cancer. Hepatocellular carcinoma deletion gene 1 (DLC1) is an antioncogene that is either expressed at low levels or not expressed in many malignant tumours. Curcumin is a promising anticancer drug that has antitumour effects in many tumours, but its mechanism of action is unclear. Our research demonstrated that EZH2 was up‐regulated in breast cancer (BC) tissues and cells, whereas DLC1 was down‐regulated, and the expression of EZH2 and DLC1 was negatively correlated in BC. By analysing the characteristics of clinical cases, we found that positive expression of EZH2 and negative expression of DLC1 may be predictors of poor prognosis in patients with triple‐negative breast cancer (TNBC). Moreover, knockdown of EZH2 expression restored the expression of DLC1 and inhibited the migration, invasion and proliferation, promoted the apoptosis, and blocked the cell cycle of MDA‐MB‐231 cells. Furthermore, we found that curcumin restored the expression of DLC1 by inhibiting EZH2; it also inhibited the migration, invasion and proliferation of MDA‐MB‐231 cells, promoted their apoptosis and blocked the cell cycle. Finally, xenograft tumour models were used to demonstrate that curcumin restored DLC1 expression by inhibiting EZH2 and also inhibited the growth and promoted the apoptosis of TNBC cells. In conclusion, our results suggest that curcumin can inhibit the migration, invasion and proliferation, promote the apoptosis, block the cycle of TNBC cells and restore the expression of DLC1 by inhibiting the expression of EZH2.     

LncRNA AC009686.2促进乳腺癌细胞增殖和侵袭

长非编码RNAs(long non-coding RNAs,LncRNAs)作为一类基因表达的调控因子,在多种肿瘤的发生发展中发挥关键作用,然而LncRNAs在乳腺癌中的作用及相关机制尚未完全阐明.为了寻找在乳腺癌发生发展中起关键作用的LncRNAs,本研究通过分析TCGA数据库发现,LncRNA AC009686.2...     

Long non‐coding RNA FTH1P3 activates paclitaxel resistance in breast cancer through miR‐206/ABCB1

Emerging evidence has indicated the important function of long non‐coding RNAs (lncRNAs) in tumour chemotherapy resistance. However, the underlying mechanism is still ambiguous. In this study, we investigate the physiopathologic role of lncRNA ferritin heavy chain 1 pseudogene 3 (FTH1P3) on the paclitaxel (PTX) resistance in breast cancer. Results showed that lncRNA FTH1P3 was up‐regulated in paclitaxel‐resistant breast cancer tissue and cells (MCF‐7/PTX and MDA‐MB‐231/PTX cells) compared with paclitaxel‐sensitive tissue and parental cell lines (MCF‐7, MDA‐MB‐231). Gain‐ and loss‐of‐function experiments revealed that FTH1P3 silencing decreased the 50% inhibitory concentration (IC50) value of paclitaxel and induced cell cycle arrest at G2/M phase, while FTH1P3‐enhanced expression exerted the opposite effects. In vivo, xenograft mice assay showed that FTH1P3 silencing suppressed the tumour growth of paclitaxel‐resistant breast cancer cells and ABCB1 protein expression. Bioinformatics tools and luciferase reporter assay validated that FTH1P3 promoted ABCB1 protein expression through targeting miR‐206, acting as a miRNA “sponge.” In summary, our results reveal the potential regulatory mechanism of FTH1P3 on breast cancer paclitaxel resistance through miR‐206/ABCB1, providing a novel insight for the breast cancer chemoresistance.     

Interleukin‐6 contributes to chemoresistance in MDA‐MB‐231 cells via targeting HIF‐1α

Chemoresistance is a critical challenge in the clinical treatment of triple‐negative breast cancer (TNBC). It has been well documented that inflammatory mediators from tumor microenvironment are involved in the pathogenesis of TNBC and might be related to chemoresistance of cancer cells. In this study, the contribution of interleukin‐6 (IL‐6), one of the principal oncogenic molecules, in chemoresistance of a TNBC cell line MDA‐MB‐231 was first investigated. The results showed that IL‐6 treatment could induce upregulation of HIF‐1α via the activation of STAT3 in MDA‐MB‐231 cells, which consequently contributed to its effect against chemotherapeutic drug‐induced cytotoxicity and cell apoptosis. However, knockdown of HIF‐1α attenuated such effect via affecting the expressions of apoptosis‐related molecules as Bax and Bcl‐2 and drug transporters as P‐gp and MRP1. This study indicated that targeting at IL‐6/HIF‐1α signaling pathway might be an effective strategy to overcome chemoresistance in TNBC therapy.     

ZEB1‐AS1: A crucial cancer‐related long non‐coding RNA

Long non‐coding RNAs (lncRNAs) recently emerge as a novel class of non‐coding RNAs (ncRNAs) with larger than 200 nucleotides in length. Due to lack an obvious open reading frame, lncRNAs have no or limited protein‐coding potential. To date, accumulating evidence indicates the vital regulatory function of lncRNAs in pathological processes of human diseases, especially in carcinogenesis and development. Deregulation of lncRNAs not only alters cellular biological behavior, such as proliferation, migration and invasion, but also represents the poor clinical outcomes. Zinc finger E‐box binding homeobox 1 antisense 1 (ZEB1‐AS1), an outstanding cancer‐related lncRNA, is identified as an oncogenic regulator in diverse malignancies. Dysregulation of ZEB1‐AS1 has been demonstrated to exhibit a pivotal role in tumorigenesis and progression, suggesting its potential clinical value as a promising biomarker or therapeutic target for cancers. In this review, we make a summary on the current findings regarding the biological functions, underlying mechanisms and clinical significance of ZEB1‐AS1 in cancer progression.     

Aberrant methylation of WD‐repeat protein 41 contributes to tumour progression in triple‐negative breast cancer

WD‐repeat proteins are implicated in a variety of biological functions, most recently in oncogenesis. However, the underlying function of WD‐repeat protein 41 (WDR41) in tumorigenesis remains elusive. The present study was aimed to explore the role of WDR41 in breast cancer. Combined with Western blotting and immunohistochemistry, the results showed that WDR41 was expressed at low levels in breast cancer, especially in triple‐negative breast cancer (TNBC). Using methylation‐specific PCR (MSP), we observed that WDR41 presented hypermethylation in MDA‐MB‐231 cells. Methylation inhibitor 5‐aza‐2′‐deoxycytidine (5‐aza‐dC) management increased the expression of WDR41 in MDA‐MB‐231 cells, but not in MCF‐10A (normal mammary epithelial cells) or oestrogen receptor‐positive MCF‐7 breast cancer cells. WDR41‐down‐regulation promoted, while WDR41‐up‐regulation inhibited the tumour characteristics of TNBC cells including cell viability, cell cycle and migration. Further, WDR41‐up‐regulation dramatically suppressed tumour growth in vivo. Mechanistically, WDR41 protein ablation activated, while WDR41‐up‐regulation repressed the AKT/GSK‐3β pathway and the subsequent nuclear activation of β‐catenin in MDA‐MB‐231 cells, and 5‐aza‐dC treatment enhanced this effect. After treatment with the AKT inhibitor MK‐2206, WDR41‐down‐regulation‐mediated activation of the GSK‐3β/β‐catenin signalling was robustly abolished. Collectively, methylated WDR41 in MDA‐MB‐231 cells promotes tumorigenesis through positively regulating the AKT/GSK‐3β/β‐catenin pathway, thus providing an important foundation for treating TNBC.     

LncRNA NR2F1‐AS1 regulates hepatocellular carcinoma oxaliplatin resistance by targeting ABCC1 via miR‐363

Emerging evidence has validated the vital role of long non‐coding RNA (lncRNA) in the chemoresistance of cancer treatment. In the present study, we investigate the function of lncRNA NR2F1‐AS1 on oxaliplatin (OXA) resistance of hepatocellular carcinoma (HCC) and discover the underlying molecular mechanism. Results revealed that lncRNA NR2F1‐AS1 was up‐regulated in oxaliplatin‐resistant HCC tissue and cells using microarray analysis and RT‐PCR. Meanwhile, ABCC1 protein was overexpressed in OXA‐resistant HCC cells (Huh7/OXA and HepG2/OXA). In vitro, NR2F1‐AS1 knockdown reduced the invasion, migration, drug‐resistant gene (MDR1, MRP5, LRP1) and IC50 value in Huh7/OXA and HepG2/OXA cells. In vivo, NR2F1‐AS1 knockdown decreased the tumour weight of HCC cells. Bioinformatics tools and luciferase reporter assay confirmed miR‐363 targeted the 3′‐UTR of NR2F1‐AS1 and ABCC1 mRNA, presenting that NR2F1‐AS1 promoted ABCC1 expression through endogenous sponging miR‐363. In summary, results conclude that NR2F1‐AS1 regulates HCC OXA resistance through targeting miR‐363‐ABCC1 pathway, providing a vital theoretic mechanism and therapeutic target for HCC chemoresistance.     

Tumor‐associated macrophages (TAMs) depend on ZEB1 for their cancer‐promoting roles

Accumulation of tumor‐associated macrophages (TAMs) associates with malignant progression in cancer. However, the mechanisms that drive the pro‐tumor functions of TAMs are not fully understood. ZEB1 is best known for driving an epithelial‐to‐mesenchymal transition (EMT) in cancer cells to promote tumor progression. However, a role for ZEB1 in macrophages and TAMs has not been studied. Here we describe that TAMs require ZEB1 for their tumor‐promoting and chemotherapy resistance functions in a mouse model of ovarian cancer. Only TAMs that expressed full levels of Zeb1 accelerated tumor growth. Mechanistically, ZEB1 expression in TAMs induced their polarization toward an F4/80^low pro‐tumor phenotype, including direct activation of Ccr2. In turn, expression of ZEB1 by TAMs induced Ccl2, Cd74, and a mesenchymal/stem‐like phenotype in cancer cells. In human ovarian carcinomas, TAM infiltration and CCR2 expression correlated with ZEB1 in tumor cells, where along with CCL2 and CD74 determined poorer prognosis. Importantly, ZEB1 in TAMs was a factor of poorer survival in human ovarian carcinomas. These data establish ZEB1 as a key factor in the tumor microenvironment and for maintaining TAMs’ tumor‐promoting functions.     

LncRNA BDNF‐AS inhibits proliferation,migration, invasion and EMT in oesophageal cancer cells by targeting miR‐214

This study was aimed at exploring the effect of lncRNA BDNF‐AS on cell proliferation, migration, invasion and epithelial‐to‐mesenchymal transition (EMT) of oesophageal cancer (EC) cells. The expression of BDNF‐AS and miR‐214 in tissue samples and cells was measured by qRT‐PCR. The targeted relationship between BDNF‐AS and miR‐214 was analysed by dual‐luciferase reporter assay. After cell transfection, the cell proliferation activity was assessed by MTS method, while the migrating and invading abilities were evaluated by transwell assay. LncRNA BDNF‐AS was remarkably down‐regulated, while miR‐214 was up‐regulated in EC tissues and cells in comparison with normal tissues and cells. Overexpression of BDNF‐AS significantly inhibited the abilities of cell proliferation, migration and invasion as well as the EMT processes of EC cells. The bioinformatics analysis and luciferase assay indicated that BDNF‐AS could be directly bound by miR‐214. Furthermore, overexpression of miR‐214 and BDNF‐AS exerted suppressive influence on EC cell multiplication, migration, invasion and EMT processes. LncRNA BDNF‐AS restrained cell proliferation, migration, invasion and EMT processes in EC cells by targeting miR‐214.     

ZEB1‐mediated vasculogenic mimicry formation associates with epithelial–mesenchymal transition and cancer stem cell phenotypes in prostate cancer

The zinc finger E‐box‐binding homeobox 1 (ZEB1) induced the epithelial–mesenchymal transition (EMT) and altered ZEB1 expression could lead to aggressive and cancer stem cell (CSC) phenotypes in various cancers. Tissue specimens from 96 prostate cancer patients were collected for immunohistochemistry and CD34/periodic acid–Schiff double staining. Prostate cancer cells were subjected to ZEB1 knockdown or overexpression and assessment of the effects on vasculogenic mimicry formation in vitro and in vivo. The underlying molecular events of ZEB1‐induced vasculogenic mimicry formation in prostate cancer were then explored. The data showed that the presence of VM and high ZEB1 expression was associated with higher Gleason score, TNM stage, and lymph node and distant metastases as well as with the expression of vimentin and CD133 in prostate cancer tissues. Furthermore, ZEB1 was required for VM formation and altered expression of EMT‐related and CSC‐associated proteins in prostate cancer cells in vitro and in vivo. ZEB1 also facilitated tumour cell migration, invasion and clonogenicity. In addition, the effects of ZEB1 in prostate cancer cells were mediated by Src signalling; that is PP2, a specific inhibitor of the Src signalling, dose dependently reduced the p‐Src⁵²⁷ level but not p‐Src⁴¹⁶ level, while ZEB1 knockdown also down‐regulated the level of p‐Src⁵²⁷ in PC3 and DU‐145 cells. PP2 treatment also significantly reduced the expression of VE‐cadherin, vimentin and CD133 in these prostate cancer cells. Src signalling mediated the effects of ZEB1 on VM formation and gene expression.