Pengfei Xu

LncRNA SNHG29 Suppresses Epithelial Ovarian Cancer Cell Invasion and Migration via miR-20b-3p/GNAI3 Axis Regulation

Epithelial ovarian cancer (EOC) is the deadliest gynecologic cancer in women. Long noncoding RNAs (lncRNAs) are critically involved in malignant progression by modulating proliferation, apoptosis, invasion, metastasis, and chemotherapy resistance. The long noncoding RNA small nucleolar RNA host gene 29 (SNHG29) is involved in multiple malignancies, although its role in EOC has not been elucidated. In our study, SNHG29 expression was significantly downregulated in EOC tissues and was negatively related to lymphatic invasion in EOC patients according to data from the TCGA database. Kaplan-Meier survival analysis revealed that among patients with early stage EOC, compared with patients with low SNHG29 expression levels, patients with high expression levels had markedly longer progression-free survival (PFS) and overall survival (OS) times. Further studies suggested that SNHG29 knockdown enhanced the invasive and migrative potential of EOC cells, whereas SNHG29 overexpression attenuated the invasive and migrative potential capacity. In animal experiments, SNHG29 knockdown significantly promoted lung metastasis in tail vein injection models. Mechanistically, the downregulation of SNHG29 expression inhibited its competitive endogenous RNA activity, resulting in increased miR-20b-3p availability and subsequent degradation of the downstream target gene GNAI3, as determined by RNA immunoprecipitation (RIP) and luciferase reporter gene assays. miR-20b-3p inhibition significantly reduces the invasive and metastatic capabilities of EOC cells resulting from a reduction in SNHG29 expression. Our study revealed that SNHG29 may be a promising prognostic factor and therapeutic target for EOC.

Differential effects of the LncRNA RNF157-AS1 on epithelial ovarian cancer cells through suppression of DIRAS3- and ULK1-mediated autophagy

AbstractAnalyses of several databases showed that the lncRNA RNF157 Antisense RNA 1 (RNF157-AS1) is overexpressed in epithelial ovarian cancer (EOC) tissues. In our study, suppressing RNF157-AS1 strikingly reduced the proliferation, invasion, and migration of EOC cells compared with control cells, while overexpressing RNF157-AS1 greatly increased these effects. By RNA pulldown assays, RNA binding protein immunoprecipitation (RIP) assays, and mass spectrometry, RNF157-AS1 was further found to be able to bind to the HMGA1 and EZH2 proteins. Chromatin immunoprecipitation (ChIP) assays showed that RNF157-AS1 and HMGA1 bound to the ULK1 promoter and prevented the expression of ULK1. Additionally, RNF157-AS1 interacted with EZH2 to bind to the DIRAS3 promoter and diminish DIRAS3 expression. ULK1 and DIRAS3 were found to be essential for autophagy. Combination autophagy inhibitor and RNF157-AS1 overexpression or knockdown, a change in the LC3 II/I ratio was found using immunofluorescence (IF) staining and western blot (WB) analysis. The autophagy level also was confirmed by autophagy/cytotoxicity dual staining. However, the majority of advanced EOC patients require platinum-based chemotherapy, since autophagy is a cellular catabolic response to cell stress. As a result, RNF157-AS1 increased EOC cell sensitivity to chemotherapy and death under cis-platinum (DDP) treatment by suppressing autophagy, as confirmed by cell count Kit-8 (CCK8) assays, flow cytometry, and autophagy/cytotoxicity dual staining. Therefore, the OS and PPS times were longer in EOC patients with elevated RNF157-AS1 expression. RNF157-AS1-mediated autophagy has potential clinical significance in DDP chemotherapy for EOC patients.

RETRACTED: LBX2‐AS1 promotes ovarian cancer progression by facilitating E2F2 gene expression via miR‐455‐5p and miR‐491‐5p sponging

Abstract LBX2‐AS1 is a long non‐coding RNA that facilitates the development of gastrointestinal cancers and lung cancer, but its participation in ovarian cancer development remained uninvestigated. Clinical data retrieved from TCGA ovarian cancer database and the clinography of 60 ovarian cancer patients who received anti‐cancer treatment in our facility were analysed. The overall cell growth, colony formation, migration, invasion, apoptosis and tumour formation on nude mice of ovarian cancer cells were evaluated before and after lentiviral‐based LBX2‐AS1 knockdown. ENCORI platform was used to explore LBX2‐AS1‐interacting microRNAs and target genes of the candidate microRNAs. Luciferase reporter gene assay and RNA pulldown assay were used to verify the putative miRNA‐RNA interactions. Ovarian cancer tissue specimens showed significant higher LBX2‐AS1 expression levels that non‐cancerous counterparts. High expression level of LBX2‐AS1 was significantly associated with reduced overall survival of patients. LBX2‐AS1 knockdown significantly down‐regulated the cell growth, colony formation, migration, invasion and tumour formation capacity of ovarian cancer cells and increased their apoptosis in vitro. LBX2‐AS1 interacts with and thus inhibits the function of miR‐455‐5p and miR‐491‐5p, both of which restrained the expression of E2F2 gene in ovarian cancer cells via mRNA targeting. Transfection of miRNA inhibitors of these two miRNAs or forced expression of E2F2 counteracted the effect of LBX2‐AS1 knockdown on ovarian cancer cells. LBX2‐AS1 was a novel cancer‐promoting lncRNA in ovarian cancer. This lncRNA increased the cell growth, survival, migration, invasion and tumour formation of ovarian cancer cells by inhibiting miR‐455‐5p and miR‐491‐5p, thus liberating the expression of E2F2 cancer‐promoting gene.

Long noncoding RNA ZEB1-AS1 affects paclitaxel and cisplatin resistance by regulating MMP19 in epithelial ovarian cancer cells

The long noncoding RNA (lncRNA) ZEB1-AS1 is reported overexpressed in sensitive ovarian cancer cells A2780 compared with paclitaxel (PTX)-and cisplatin (DDP)- resistant. However, the function and mechanism of ZEB1-AS1 in EOC cells still unknown. We used quantitative real-time PCR (qPCR) to detect ZEB1-AS1 expression in A2780 and A2780/R cells. A combination of siRNA, plasmids, CCK8 and flow cytometry was used to detect the effect of ZEB1-AS1 on ovarian cancer cell A2780 PTX and DDP resistance. Transcriptome sequencing, qPCR, and western blot were used for further mechanistic studies. ZEB1-AS1 depletion using siRNA in chemosensitive A2780 cells significantly increased PTX and DDP resistance. In contrast, ZEB1-AS1 overexpression in PTX- and DDP-resistant A2780/resistant (A2780/R) cells reversed the observed drug resistance. Thus, ZEB1-AS1 plays an important role in PTX and DDP resistance in EOC cells. However, quantitative real-time PCR (qPCR) and western blot results suggested that ZEB1-AS1 did not regulate chemoresistance through regulation of ZEB1 protein. We used sequencing to detect mRNA expression changes in A2780 cells after ZEB1-AS1 silencing. The results indicated that MMP19 was the likely downstream factor of ZEB1-AS1. We further examined whether ZEB1-AS1 played an important role in chemoresistance by silencing MMP19 in ZEB1-AS1-overexpressing cells. CCK8 assay results suggested that MMP19 knockdown promoted ZEB1-AS1-induced chemoresistance to PTX and DDP in A2780 cells. This study is the first to reveal that ZEB1-AS1 plays a pivotal role in cancer chemoresistance.