Overexpression of microRNA-196b Accelerates Invasiveness of Cancer Cells in Recurrent Epithelial Ovarian Cancer Through Regulation of Homeobox A9.

Although microRNAs (miRNAs) are known to influence messenger RNA post-transcriptional control and contribute to human tumorigenesis, little is known about the differences in miRNA expression between primary and recurrent epithelial ovarian cancer (EOC). The purpose of this study was to assess the differential miRNA expression between primary and recurrent EOC and to investigate whether miR-196b could regulate the expression of the Homeobox A9 (HOXA9) gene, and thus affect the invasiveness of cancer cells in recurrent EOC. Microarrays were used to generate the expression profiles of 6658 miRNAs from samples of 10 patients with EOC. miRNA expression patterns were compared between primary and recurrent EOC. Aberrantly expressed miRNA, associated genes, and invasion activities were validated by a luciferase assay and an in vitro invasion assay. miRNA microarray analysis identified 33 overexpressed miRNAs (including miR-196b) and 18 under expressed miRNAs in recurrent EOC from 6658 human miRNAs. HOXA9 expression was inversely correlated with miR-196b levels in recurrent EOC. We noted that miR-196b induced ovarian cancer cell invasiveness in recurrent EOC by an in vitro invasion assay. Overexpression of miR-196b may contribute to invasion activities in recurrent EOC by regulating the HOXA9 gene. Moreover, miR-196b can be a potential biomarker in recurrent EOC.

Chong GO ，Jeon HS ，Han HS ，Son JW ，Lee YH ，Hong DG ，Park HJ ，Lee YS ，Cho YL ... -  《-》

Differential MicroRNA Expression Profiles in Primary and Recurrent Epithelial Ovarian Cancer.

Although it has been shown that microRNAs influence messenger RNA post-transcriptional control and can attribute to human tumorigenesis, little is known regarading the differences in microRNA expression between primary and recurrent epithelial ovarian cancer (EOC). The purpose of the present study was to assess the differential expression of microRNA between primary and recurrent EOC. Between September 2013 and May 2014, the expression of microRNAs in tumor tissues from 5 primary and 5 recurrent EOC cases were analyzed. The tumor histotype was serous cystadenocarcinoma in all patients. Total RNA was extracted from tumor samples and microRNA expression levels were measured by performing microarray analysis. Expression levels were compared between the two groups and analyzed statistically. Several microRNAs were differentially expressed in recurrent EOC compared to primary EOC, including 18 under-expressed microRNAs and 33 over-expressed microRNAs among 6,658 human microRNAs. Four specific microRNAs were the most significantly over-expressed in recurrent EOC: miR-551b, miR-19b, miR-196b and miR-3198. Moreover, 4 specific microRNAs were the most significantly down-expressed in recurrent EOC: miR-8084, miR-3201, miR-3613 and miR-7515. Based on our data, dysregulation of microRNA expression was associated with the recurrence of EOC. Moreover, significantly over- and down-regulated microRNAs can be useful biomarkers for the prediction of recurrence in EOC.

Chong GO ，Jeon HS ，Han HS ，Son JW ，Lee YH ，Hong DG ，Lee YS ，Cho YL ... -  《-》

MiR-205 promotes motility of ovarian cancer cells via targeting ZEB1.

To investigate the clinical significance of microRNA-205 (miR-205) and zinc finger E-box binding homeobox 1 (ZEB1) in epithelial ovarian cancer (EOC) and the underlying mechanisms by which they are involved into tumorigenesis. Expression levels of miR-205 and ZEB1 mRNA in EOC tissues were detected by quantitative real-time PCR. Their associations with clinicopathological features of EOC patients were statistically analyzed. Luciferase reporter assay was used to confirm target associations between miR-205 and ZEB1. After that, the functions of miR-205-ZEB1 axis on cell migration and invasion were further determined by transwell assay in vitro. Expression levels of miR-205 (P=0.0001) and ZEB1 mRNA (P<0.0001) in clinical EOC tissues were significantly higher and lower than those in normal tissues, respectively. Interestingly, there was a negative correlation between miR-205 and ZEB1 mRNA expression in EOC tissues (P=0.01). Additionally, miR-205-upregulation and/or ZEB1-downregulation were significantly associated with high pathological grade and advanced clinical stage of EOC patients (all P<0.05). Meantime, luciferase reporter assays identified ZEB1 as a direct target of miR-205 in EOC cells. Moreover, miR-205 blockage inhibited, whereas miR-205 mimics promoted the motility of EOC cells in vitro. Importantly, all the alterations of the above cellular phenotypes by blocking or enhancing of miR-205 could be alleviated by subsequent suppression or re-introduction of its target ZEB1, respectively. MiR-205, acting as an oncogenic miRNA, may promote the clinical progression of EOC patients and enhance the cellular motility in vitro by directly and negatively regulating ZEB1, providing a potential therapeutic strategy for suppression of EOC metastasis.

Niu K ，Shen W ，Zhang Y ，Zhao Y ，Lu Y ... -  《-》

MiR-135a functions as a tumor suppressor in epithelial ovarian cancer and regulates HOXA10 expression.

The activation of homeobox A10 (HOXA10) has been proved to be an important event in epithelial ovarian carcinogenesis, yet its regulation in epithelial ovarian cancer (EOC) is still not fully understood. Here, we aimed to reveal the mechanism that a predicted target miRNA regulates HOXA10 expression and the association of its expression with progression of EOC. Here, by using computer-assisted algorithms from PicTar, TargetScan, and miRBase, we identified that the predicted target miRNA of HOXA10 was miR-135a. MiR-135a expression in EOC tissues and controls was measured with quantitative RT-PCR. The role of miR-135a and HOXA10 in the growth and survival of several EOC cell lines was determined with several in vitro approaches. We found that miR-135a expression was downregulated in an EOC patient cohort. Also, patients with low miR-135a expression had shorter overall survival and progression-free survival durations than those with high expression. Functional analysis of three EOC-derived cell lines (SKOV-3, HEY, and OVCAR-3) demonstrated that miR-135a directly regulated HOXA10 expression by targeting its 3'-UTR. Inhibition of HOXA10 expression with miR-135a mimics and HOXA10 siRNA consistently resulted in cell apoptosis with concomitant enhancement of caspase-3, increase of p53 expression and reduction of Bcl-2 expression, and also suppressed cell growth and adhesion. These findings suggest that ubiquitous loss of miR-135a expression is a critical mechanism for the overexpression of HOXA10 in EOC cells, which is implicated in epithelial ovarian carcinogenesis. Furthermore, miR-135a may be predictive of EOC prognosis.

Tang W ，Jiang Y ，Mu X ，Xu L ，Cheng W ，Wang X ... -  《-》

MicroRNA-145 targets TRIM2 and exerts tumor-suppressing functions in epithelial ovarian cancer.

Epithelial ovarian cancer (EOC) is one of the most common cancers in women worldwide but relatively little is known about its molecular pathogenesis. MicroRNAs, which regulate gene expression post-transcriptionally, have emerged as key players in tumorigenesis. The present study aims to investigate the dysregulation of miR-145 in EOC. miRNA expression was assessed in EOC tissues and cell lines by quantitative reverse transcription (RT)-PCR. Xenograft mouse model was used for evaluation of the effect of miR-145 on tumor growth. Cell proliferation, colony formation assays, invasion assay, flow cytometry, Western blot and gene expression analysis were used for identification of the functional role of miR-145 in EOC cells. Luciferase reporter assay was used to confirm the interaction between miR-145 and its target mRNA 3'-UTR. miR-145 expression was downregulated in EOC tissues and cell lines as compared with normal ovarian tissues. Transfection of miR-145 agomiR significantly inhibited the proliferation, colony forming ability, invasiveness and in vivo tumorigenicity of EOC cells. Transfection of agomiR-145 into EOC cells also markedly induced apoptosis. Furthermore, computational algorithm combined with luciferase reporter assays identified TRIM2 as the direct target of miR-145 in EOC cells. To this end, agomiR-145 downregulated TRIM2 to derepress Bim (a pro-apoptotic Bcl-2 family member degraded by TRIM2). These data confirmed the tumor-suppressing function of miR-145 in EOC and identified TRIM2 as a new miR-145 target. In vivo delivery of agomiR-145 might be a feasible approach for miRNA-directed cancer therapy.

Chen X ，Dong C ，Law PT ，Chan MT ，Su Z ，Wang S ，Wu WK ，Xu H ... -  《-》