WWOX promotes apoptosis and inhibits autophagy in paclitaxel­treated ovarian carcinoma cells.

Although paclitaxel (PTX) is a first­line chemotherapeutic agent for the treatment of epithelial ovarian cancer (EOC), its clinical use is restricted by chemoresistance. Autophagy is believed to promote drug resistance, and WW domain­containing oxidoreductase (WWOX) has been predicted to serve an essential role in apoptosis induction and to suppress autophagy in various tumor cell types. In the present study, the role of WWOX was demonstrated using PTX­treated EOC cells. Cell viability and apoptosis were detected using Cell Counting Kit­8, morphological and flow cytometric analyses. WWOX and phosphorylated (p)­WWOX were highly expressed in PTX­treated sensitive EOC cells (A2780), which was accompanied by activation of the apoptosis­related proteins caspase­3 and poly (ADP­ribose) polymerase (PARP). Conversely, PTX­resistant EOC cells (A2780/T) were characterized by reduced WWOX expression and constant phosphorylation levels, as well as undetectable levels of activated caspase­3 and PARP when cells were treated with PTX. The altered expression of WWOX between the two cell types was further validated by reverse transcription­-quantitative PCR. The apoptosis­inducing role of WWOX was also confirmed by flow cytometry after WWOX overexpression was induced in PTX­treated A2780 cells. These findings indicated that WWOX activation may inhibit chemoresistance and trigger cancer cell death. The upregulated expression levels of the autophagy­related protein 12­5 complex, Beclin­1 and LC3, as well as the downregulation of P62, were also detected following PTX treatment, suggesting that PTX induced autophagic flux in both types of EOC cells. This conclusion was further supported by visualizing the accumulation of autophagosome and autolysosome vesicles, using confocal microscopy and transmission electron microscopy. PTX was also shown to inhibit mTOR signaling, indicated by a decreased level of p­mTOR and increased expression of eukaryotic translation initiation factor 4E­binding protein 1. Finally, the interaction between WWOX, mTOR and autophagy was investigated via WWOX transfection experimentation, and indicated that WWOX activated mTOR whilst inhibiting autophagy. These data indicated that WWOX may serve a critical role in PTX­induced apoptosis and could suppress autophagy by downregulating essential autophagic effectors in EOC cells via mTOR signaling.

miR-187* Enhances SiHa Cervical Cancer Cell Oncogenicity Via Suppression of WWOX.

BACKGROUND/AIM: Cervical cancer is one of the most common cancers worldwide and a major cause of cancer-related mortality among women. Previous studies have reported that microRNA-miR-187*, which is one of the non-coding parts of the genome producing small conserved ribonucleic acids, is associated with various cancers. In this study, we explored the function of miR-187* in cervical cancer cells. MATERIALS AND METHODS: miR-187* mimic, WWOX reporter constructs, siRNA and overexpression constructs were transfected into SiHa cells to investigate the function and regulatory mechanisms of miR-187*. RESULTS: Exogenous miR-187* was found to increase the oncogenic phenotypes of SiHa cells. The tumor suppressor gene WWOX is a novel target of miR-187* in SiHa cells. WWOX siRNA suppressed endogenous WWOX expression and increased the oncogenic phenotypes of SiHa cells. Exogenous WWOX expression was able to suppress the oncogenic phenotypes of SiHa cells and rescue cells from miR-187*-induced migration. CONCLUSION: miR-187* seems to enhance SiHa cervical cancer cell oncogenicity via suppression of the WWOX pathway.

WWOX regulates the Elf5/Snail1 pathway to affect epithelial-mesenchymal transition of ovarian carcinoma cells in vitro.

OBJECTIVE: Ovarian cancer is a highly invasive type of cancer. A previous study demonstrated that E-cadherin expression was upregulated in a human ovarian cancer cell line with a high expression of WW domain-containing oxidoreductase (WWOX), which is a tumor suppressor. Also, the migration and invasion ability of these cells was reduced. Snail family members are involved in the epithelial-to-mesenchymal transition (EMT) of ovarian cancer cells, and the expression of Snail family members is regulated by the transcription factor Elf5. The aim of the present research was to elucidate the role of WWOX in EMT of ovarian carcinoma cells through the Elf5/Snail pathway by gain and loss of function approaches in in vitro experiments. MATERIALS AND METHODS: First, a WWOX gene expressing plasmid was transfected into CD133+CD117+ HO8910 ovarian carcinoma cells, and an Elf5 shRNA plasmid was transfected into these cells to assess the changes in EMT-related factors, including Snail1, and the invasive ability of tumor cells ability. Second, the human ovarian carcinoma cell lines HO8910 and SKOV3 were divided into six groups to detect the same indicators. RESULTS: The results demonstrated that the high expression of WWOX resulted in an increased E-cadherin expression, decreased Snail1 activity, and decreased invasion ability in CD133+CD117+ HO8910 cells. Elf5 shRNA transfection did not affect the WWOX expression; however, it decreased the expression of E-cadherin and Elf5 activity, while increasing Snail1 activity and invasion ability in CD133+CD117+ HO8910 cells. It was also observed that WWOX overexpression in HO8910 and SKOV3 cells inhibited the expression of EMT-related proteins and inhibited cell migration and invasion. CONCLUSIONS: Taken together, the results of the present report suggest that WWOX can decrease Snail1 activity by enhancing the activity of Elf5, thus upregulating E-cadherin expression and eventually inhibiting EMT of ovarian carcinoma.