LncRNA MALAT1/miR‐129 axis promotes glioma tumorigenesis by targeting SOX2

We aimed to explore the interaction among lncRNA MALAT1, miR‐129 and SOX2. Besides, we would investigate the effect of MALAT1 on the proliferation of glioma stem cells and glioma tumorigenesis. Differentially expressed lncRNAs in glioma cells and glioma stem cells were screened out with microarray analysis. The targeting relationship between miR‐129 and MALAT1 or SOX2 was validated by dual‐luciferase reporter assay. The expressions of MALAT1, miR‐129 and SOX2mRNA in both glioma non‐stem cells and glioma stem cells were examined by qRT‐PCR assay. The impact of MALAT1 and miR‐129 on glioma stem cell proliferation was observed by CCK‐8 assay, EdU assay and sphere formation assay. The protein expression of SOX2 was determined by western blot. The effects of MALAT1 and miR‐129 on glioma tumour growth were further confirmed using xenograft mouse model. The mRNA expression of MALAT1 was significantly up‐regulated in glioma stem cells compared with non‐stem cells, while miR‐129 was significantly down‐regulated in glioma stem cells. MALAT1 knockdown inhibited glioma stem cell proliferation via miR‐129 enhancement. Meanwhile, miR‐129 directly targeted at SOX2 and suppressed cell viability and proliferation of glioma stem cells by suppressing SOX2 expression. The down‐regulation of MALAT1 and miR‐129 overexpression both suppressed glioma tumour growth via SOX2 expression promotion in vivo. MALAT1 enhanced glioma stem cell viability and proliferation abilities and promoted glioma tumorigenesis through suppressing miR‐129 and facilitating SOX2 expressions.     

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.     

Galectin-1 overexpression promotes progression and chemoresistance to cisplatin in epithelial ovarian cancer

This study was performed to investigate the role of galectin-1 (Gal-1) in epithelial ovarian cancer (EOC) progression and chemoresistance. Tissue samples from patients with EOC were used to examine the correlation between Gal-1 expression and clinical stage of EOC. The role of Gal-1 in EOC progression and chemoresistance was evaluated in vitro by siRNA-mediated knockdown of Gal-1 or lentivirus-mediated overexpression of Gal-1 in EOC cell lines. To elucidate the molecular mechanisms underlying Gal-1-mediated tumor progression and chemoresistance, the expression and activities of some signaling molecules associated with Gal-1 were analyzed. We found overexpression of Gal-1 in advanced stages of EOC. Knockdown of endogenous Gal-1 in EOC cells resulted in the reduction in cell growth, migration, and invasion in vitro, which may be caused by Gal-1''s interaction with H-Ras and activation of the Raf/extracellular signal-regulated kinase (ERK) pathway. Additionally, matrix metalloproteinase-9 (MMP-9) and c-Jun were downregulated in Gal-1-knockdown cells. Notably, Gal-1 overexpression could significantly decrease the sensitivities of EOC cells to cisplatin, which might be ascribed to Gal-1-induced activation of the H-Ras/Raf/ERK pathway and upregulation of p21 and Bcl-2. Taken together, the results suggest that Gal-1 contributes to both tumorigenesis and cisplatin resistance in EOC. Thus, Gal-1 is a potential therapeutic target for EOC.     

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.     

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.     

LncRNA PVT1 predicts prognosis and regulates tumor growth in prostate cancer

Long non-coding RNA (lncRNA) plasmacytoma variant translocation 1(PVT1) was aberrantly expressed in various cancers and is associated with tumor prognosis. Here, we aim to investigate its function in prostate cancer. Small interfering RNA against PVT1 was transfected into prostate cancer cell lines and cell growth and apoptosis were analyzed. Our results showed that PVT1 was overexpressed in prostate cancer tissues and cells. Higher levels of PVT1 indicated poorer overall survival and disease-free survival. A significant association was found between PVT1 expression and tumor stage. Besides, PVT1 knockdown significantly inhibited prostate cancer growth in vivo and in vitro and promoted cell apoptosis. PVT1 knockdown also significantly upregulated the expression of cleaved caspase-3 and cleaved caspase-9, but downregulated the expression of c-Myc in prostate cancer cell lines. Our results suggest that PVT1 played an oncogenic role in prostate cancer and could be used as a potential biomarker for diagnosis of prostate cancer.     

LncRNA DUXAP9‐206 directly binds with Cbl‐b to augment EGFR signaling and promotes non‐small cell lung cancer progression

Long noncoding RNAs (lncRNAs) are involved in the pathology of various tumours, including non‐small cell lung cancer (NSCLC). However, the underlying molecular mechanisms of their specific association with NSCLC have not been fully elucidated. Here, we report that a cytoplasmic lncRNA, DUXAP9‐206 is overexpressed in NSCLC cells and closely related to NSCLC clinical features and poor patient survival. We reveal that DUXAP9‐206 induced NSCLC cell proliferation and metastasis by directly interacting with Cbl‐b, an E3 ubiquitin ligase, and reducing the degradation of epidermal growth factor receptor (EGFR) and thereby augmenting EGFR signaling in NSCLC. Notably, correlations between DUXAP9‐206 and activated EGFR signaling were also validated in NSCLC patient specimens. Collectively, our findings reveal the novel molecular mechanisms of DUXAP9‐206 in mediating the progression of NSCLC and DUXAP9‐206 may serve as a potential target for NSCLC therapy.     

The non‐coding RNA OTUB1‐isoform2 promotes ovarian tumour progression and predicts poor prognosis

Ovarian cancer is the leading malignancy of the female reproductive system and is associated with inconspicuous early invasion and metastasis. We have previously reported that the oncogene OTUB1 plays a crucial role in ovarian cancer progression, but the role of its isoform, the non‐coding RNA OTUB1‐isoform2, in ovarian cancer is still elusive. Here, we reported that OTUB1‐isoform2 expression in ovarian cancer tissues was significantly higher than that in the paired paratumorous tissues (P < .01). The patients with high expression of OTUB1‐isoform2 had larger tumours than those with low expression (P < .05). The high expression of OTUB1‐isoform2 was correlated with the involvement of bilateral ovaries (P < .05), lymph node metastasis (P < .05), vascular invasion (P < .05), greater omentum involvement (P < .01), fallopian tube involvement (P < .05), advanced FIGO stages (P < .01) and recurrence (P < .01). Moreover, OTUB1‐isoform2 served as an independent negative prognostic predictor for disease‐free survival (DFS) and disease‐specific survival (DSS). Overexpression of OTUB1‐isoform2 in the ovarian cancer cells stimulated cell proliferation, migration and invasion both in vitro and in vivo. In summary, our study suggested that OTUB1‐isoform2 is a novel prognostic biomarker with independent oncogenic functions for ovarian cancer.     

TP73‐AS1 promotes breast cancer cell proliferation through miR‐200a‐mediated TFAM inhibition

P73 antisense RNA 1T (TP73‐AS1 or PDAM) is a long non‐coding RNA, which can regulate apoptosis through regulation of p53 signaling‐related anti‐apoptotic genes. An abnormal change of TP73‐AS1 expression was noticed in cancers. The effects of TP73‐AS1 in breast cancer (BC) growth and the underlying mechanism remain unclear so far. In the present study, the effect of TP73‐AS1 in BC cell lines and clinical tumor samples was detected so as to reveal its role and function. In the present study, TP73‐AS1 was specifically upregulated in BC tissues and BC cell lines and was correlated to a poorer prognosis in patients with BC. TP73‐AS1 knocking down suppressed human BC cell proliferation in vitro through regulation of TFAM. In our previous study, we demonstrated that miR‐200a inhibits BC cell proliferation through targeting TFAM; here we revealed that TP73‐AS1 could regulate miR‐200a through direct targeting. Moreover, TP73‐AS1 might compete with TFAM for miR‐200a binding thus to promote TFAM expression. Data from the present study revealed that TP73‐AS1 promoted BC cell proliferation through acting as a competing endogenous RNA (ceRNA) by sponging miR‐200a. In conclusion, we regarded TP73‐AS1 as an oncogenic lncRNA promoting BC cell proliferation and a potential target for human BC treatment.     

LncRNA MNX1-AS1 promotes the progression of cervical cancer through activating MAPK pathway

Long noncoding RNAs (lncRNAs) have been discovered as significant regulators in a wide range of human cancers. Among them, lncRNA MNX1-AS1 has been proved to be an oncogene in ovarian cancer and glioblastoma. However, the regulatory mechanism of MNX1-AS1 in cervical cancer remains to be understood. Therefore, this study planned to explore the role of MNX1-AS1 in cervical cancer. In the beginning, we found that the expression of MNX1-AS1 was obviously upregulated in cervical cancer tissues and cell lines. Kaplan-Meier survival analysis revealed that patients with higher MNX1-AS1 expression level suffered from shorter overall survival time than those with lower MNX1-AS1 level. Moreover, by loss-of-function and gain-of-function assay, the effect of MNX1-AS1 on cell proliferation and apoptosis was examined on cellular level. Results showed that the proliferation of Hela cells was significantly inhibited and apoptosis enhanced by the transfection of shMNX1-AS1, while overexpressing MNX1-AS1 in E6E7 cells presented the contrary results. As for mechanism investigation, it was demonstrated that overexpression of MNX1-AS1 significantly improved the expression of p-ERK1/2 and p-JNK. And the effects of MNX1-AS1 on cell proliferation and apoptosis would be diminished after inactivating the phosphorylation of either ERK or JNK. Taken together, it was identified that MNX1-AS1 promoted proliferation and inhibited apoptosis of cervical cancer cells through MAPK pathway.     

Up‐regulation of ZFAS1 indicates dismal prognosis for cholangiocarcinoma and promotes proliferation and metastasis by modulating USF1 via miR‐296‐5p

LncRNAs has been demonstrated to modulate neoplastic development by modulating downstream miRNAs and functional genes. In this study, we aimed to detect the interaction among lncRNA ZFAS1 miR‐296‐5p and USF1. We explored the proliferation, migration and invasion of cholangiocarcinoma. The differentially expressed ZFAS1 was discovered in both tissues and cell lines by qRT‐PCR. The targeting relationship between miR‐296‐5p and ZFAS1 or USF1 was validated by dual‐luciferase assay. The impact of ZFAS1 on CCA cell proliferation was observed by CCK‐8 assay. The protein expression of USF1 was determined by Western blot. The effects of ZFAS1, miR‐296‐5p and USF1 on tumour growth were further confirmed using xenograft model. LncRNA ZFAS1 expression was relatively up‐regulated in tumour tissues and cells while miR‐296‐5p was significantly down‐regulated. Knockdown of ZFAS1 significantly suppressed tumour proliferation, migration, invasion and USF1 expression. Overexpressed miR‐296‐5p suppressed cell proliferation and metastasis. Knockdown of USF1 inhibited cell proliferation and metastasis and xenograft tumour growth. In conclusion, ZFAS1 might promote cholangiocarcinoma proliferation and metastasis by modulating USF1 via miR‐296‐5p.