Galectin-3 (Gal-3) is a carbohydrate-binding protein which is thought to be involved in cancer progression but its contribution to epithelial ovarian cancer (EOC) remains unclear. The present study sought to determine the role of Gal-3 in chemoresistance of the human SKOV-3 ovarian cancer cell line to paclitaxel (PTX) using recombinant human Gal-3 (rhGal-3) and PectaSol-C modified citrus pectin (Pect-MCP) as a specific Gal-3 competitive inhibitor. Our results showed 41% increased cell proliferation, 36% decreased caspase-3 activity and 33.6% increased substrate-dependent adhesion in the presence of rhGal-3 compared to the control case (p<0.001). Treatment of cells with a non-effective dose of PTX (100nM) and 0.1% Pect-MCP in combination revealed synergistic cytotoxic effects with 75% reduced cell viability and subsequent 3.9-fold increase in caspase-3 activity. Moreover, there was 39% decrease in substrate-dependent adhesion compared to control (p<0.001). These results suggest that inhibition of Gal-3 could be a useful therapeutic tool for combination therapy of ovarian cancer.

Here we sought to determine the relationship between STAT3 activity and Galectin‐3 (Gal‐3) and to investigate the cytotoxic effect of PectaSol‐C Modified Citrus Pectin (Pect‐MCP) as a specific competitive inhibitor of Galectin‐3 (Gal‐3) in combination with Paclitaxel (PTX) to kill the ovarian cancer cell SKOV‐3 multicellular tumor spheroid (MCTS). To this order, SKOV‐3 cells in 2D and 3D cultures were treated with exogenous Gal‐3 for the assessment of STAT3 activity. Two‐way ANOVA main effect and IC₅₀ of each drug Paclitaxel (PTX) and Pect‐MCP or in combination were obtained from MTT assay results. The phosphorylated STAT3 levels, migration, invasion, integrin mRNA and p‐AKTser⁴⁷³ levels were assessed in the absence or presence of each drug alone or in combination. Gal‐3 expression levels were assessed in human serous ovarian cancer (SOC) specimens and its correlation with different integrin mRNA levels was further assessed. Our results showed that Gal‐3 expression level was significantly increased in MCTS compared to monolayer SKOV‐3 cells which triggered STAT3 phosphorylation. Moreover, Pect‐MCP synergized with PTX to kill SKOV3 MCTS through abrogation of STAT3 activity and reduced expression of its downstream target HIF‐1α, reduced integrin mRNA levels, and subsequently decreased AKT activity. There were higher expression levels of Gal‐3 in human high‐grade SOC specimens compared to the normal ovary and borderline SOC which positively and significantly correlated with α5, β2 and β6 integrin mRNA levels. Together, these results revealed for the first time that Pect‐MCP could be considered as a potential drug to enhance the PTX effect on ovarian cancer cells MCTS through inhibition of STAT3 activity.

Wnt5A, which is a member of the non-transforming Wnt protein family, is implicated in inflammatory processes. It is also highly expressed by ovarian cancer cells. ROR2, which is a member of the Ror-family of receptor tyrosine kinases, acts as a receptor or co-receptor for Wnt5A. The Wnt5A–ROR2 signaling pathway plays essential roles in the migration and invasion of several types of tumor cell and influences their cell polarity. We investigated the modulation of Wnt5A–ROR2 by inflammatory mediators and its involvement in the migration of the human ovarian cancer cell line SKOV-3. SKOV-3 cells were treated with LPS (lipopolysaccharide), LTA (lipoteichoic acid) and recombinant human IL-6 alone or in combination with STAT3 inhibitor (S1155S31-201) or NF-kB inhibitor (BAY11-7082) for 4, 8, 12, 24 and 48 h. The Wnt5A and ROR2 expression levels were determined at the gene and protein levels. Cells were transfected with specific siRNA against Wnt5A in the absence or presence of human anti-ROR2 antibody and cell migration was assessed using transwells. There was a strong downregulation of Wnt5A expression in the presence of STAT3 or NF-kB inhibitors. Cell stimulation with LTA or IL-6 for 8 h led to significantly increased levels of Wnt5A (5- and 3-fold higher, respectively). LPS, LTA or IL-6 treatment significantly increased ROR2 expression (2-fold after 48 h). LPS- or LTA-induced Wnt5A or ROR2 expression was abrogated in the presence of STAT3 inhibitor (p < 0.001). IL-6-induced Wnt5A expression was abrogated by both STAT3 and NF-kB inhibitors (p < 0.001). Although not significant, IL-6-induced ROR2 expression showed a modest decrease when STAT3 inhibitor was used. Moreover, cell migration was decreased by 80 % in siRNA Wnt5A-transfected cells in the presence of anti-human ROR2 antibody (p < 0.001). This study revealed for the first time that inflammatory mediators modulate Wnt5A and ROR2 through NF-kB and STAT3 transcription factors and this may play a role in ovarian cancer cell migration. The results described here provide new insight into the role of the Wnt5A–ROR2 complex in ovarian cancer progression in relation to inflammation.

In this paper, we investigate whether Wnt5A is associated with the TGF-β1/Smad2/3 and Hippo-YAP1/TAZ-TEAD pathways, implicated in epithelial to mesenchymal transition (EMT) in epithelial ovarian cancer. We used 3D and 2D cultures of human epithelial ovarian cancer cell lines SKOV-3, OVCAR-3, CAOV-4, and different subtypes of human serous ovarian cancer compared to normal ovary specimens. Wnt5A showed a positive correlation with TAZ and TGFβ1 in high- and low-grade serous ovarian cancer specimens compared to borderline serous and normal ovaries. Silencing Wnt5A by siRNAs significantly decreased Smad2/3 activation and YAP1 expression and nuclear shuttling in ovarian cancer (OvCa) cells. Furthermore, Wnt5A was required for TGFβ1-induced cell migration and invasion. In addition, inhibition of YAP1 transcriptional activity by Verteporfin (VP) altered OvCa cell migration and invasion through decreased Wnt5A expression and inhibition of Smad2/3 activation, which was reverted in the presence of exogenous Wnt5A. We found that the activation of TGFβ1 and YAP1 nuclear shuttling was promoted by Wnt5A-induced integrin alpha v. Lastly, Wnt5A was implicated in activating human primary omental mesothelial cells and subsequent invasion of ovarian cancer cells. Together, we propose that Wnt5A could be a critical mediator of EMT-associated pathways.

BACKGROUND AND OBJECTIVES: The prediction of in vitro fertilization (IVF) outcomes by anti-Müllerian hormone (AMH) measurement is getting increasing attention from clinicians. This study compares t...