These results suggest that the PCOS condition induces an inflammatory state exacerbated when obesity is present, where a higher TNF-α signaling is observed, all of which could affect glucose uptake in the tissue and may cause fertility failures in these women.

Polycystic ovary syndrome (PCOS) is an endocrine-metabolic disorder characterized by hyperandrogenism and ovulatory dysfunction but also obesity and hyperinsulinemia. These characteristics induce an insulin-resistant state in tissues such as the endometrium, affecting its reproductive functions. Myo-inositol (MYO) is an insulin-sensitizing compound used in PCOS patients; however, its insulin-sensitizing mechanism is unclear. To understand the relationship of MYO with insulin action in endometrial cells, sodium/myo-inositol transporter 1 (SMIT-1) (MYO-transporter), and MYO effects on protein levels related to the insulin pathway were evaluated. SMIT-1 was assessed in endometrial tissue from women with normal weight, obesity, insulin resistance, and PCOS; additionally, using an in vitro model of human endometrial cells exposed to an environment resembling hyperinsulinemic-obese-PCOS, MYO effect was evaluated on p-AMPK and GLUT-4 levels and glucose uptake by Western blot, immunocytochemistry, and confocal microscopy, respectively. SMIT-1 was detected in endometrial tissue from all groups and decreased in PCOS and obesity ( P < 0.05 vs. normal weight ). In the in vitro model, PCOS conditions decreased p-AMPK levels, while they were restored with MYO ( P < 0.05). The diminished GLUT-4 protein levels promoted by PCOS environment were restored by MYO through SMIT-1 and p-AMPK-dependent mechanism ( P < 0.05). Also, MYO restored glucose uptake in cells under PCOS condition through a p-AMPK-dependent mechanism. Finally, these results were similar to those obtained with metformin treatment in the same in vitro conditions. Consequently, MYO could be a potential insulin sensitizer through its positive effects on insulin-resistant tissues as PCOS-endometrium, acting through SMIT-1, provoking AMPK activation and elevated GLUT-4 levels and, consequently, increase glucose uptake by human endometrial cells. Therefore, MYO may be used as an effective treatment option in insulin-resistant PCOS women.

Ovarian cancer is the eighth most common cancer in women worldwide, and epithelial ovarian cancer (EOC) represents 90% of cases. Nerve growth factor (NGF) and its high affinity receptor tyrosine kinase A receptor (TRKA) have been associated with the development of several types of cancer, including EOC; both NGF and TRKA levels are elevated in this pathology. EOC presents high angiogenesis and several molecules have been reported to induce this process. NGF increases angiogenesis through its TRKA receptor on endothelial cells, and by indirectly inducing vascular endothelial growth factor expression. Other molecules controlled by NGF include ciclooxigenase-2, disintegrin and metalloproteinase domain-containing protein 17 (ADAM17) and calreticulin (CRT), proteins involved in crucial processes needed for EOC progression. These molecules could be modified through microRNA regulation, which could be regulated by NGF. MicroRNAs are the widest family of non-coding RNAs; they bind to 3′-UTR of mRNAs to inhibit their translation, to deadenilate or to degraded them. In EOC, a deregulation in microRNA expression has been described, including alterations of miR-200 family, cluster-17-92, and miR-23b, among others. Since the NGF-microRNA relationship in pathologies has not been studied, this review proposes that some microRNAs could be associated with NGF/TRKA activation, modifying protein levels needed for EOC progression.

Hyperandrogenemia, hyperinsulinemia, and obesity affect 60-70% of patients with Polycystic Ovarian Syndrome (PCOS), who exhibit an altered endometrial insulin signaling. The aim of the study was to evaluate whether hyperandrogenism, hyperinsulinism, and obesity present in PCOS patients impair the endometrial adiponectin signaling pathway. The ex vivo study was conducted on 27 samples from lean (n=9), obese (n=9), and obese-PCOS (n=9) patients. The in vitro assays were performed in immortalized human endometrial stromal cells stimulated with testosterone, insulin, or testosterone plus insulin. Serum steroid-hormones, adiponectin, glucose, and insulin; body mass index, free androgen index, ISI-Composite, and HOMA were evaluated in the 3 groups. Ex vivo and in vitro gene expression and protein content of adiponectin, AdipoR1, AdipoR2, and APPL1 were determined. Adiponectin serum levels were decreased in obese-PCOS patients compared to lean (78%) and obese (54%) controls (p<0.05). AdipoR1 protein and gene expression were increased in obese group vs. obese-PCOS and lean groups (2-fold, p<0.05). In turn, AdipoR2 protein and mRNA content was similar between the 3 groups. APPL1 protein levels were reduced in endometria from both obese groups, compared to lean group (6-fold, p<0.05). Testosterone plus insulin stimulation of T-HESC and St-T1b leads to a reduction of adiponectin, AdipoR1, AdipoR2, and APPL1 protein content in both endometrial cell lines (p<0.05), whereas, in the presence of testosterone or insulin alone, protein levels were similar to basal. Therefore, endometrial adiponectin-signaling pathway is impaired in hyperandrogenemic and hyperinsulinemic obese-PCOS patients, corroborated in the in vitro model, which could affect endometrial function and potentially the implantation process.

Nerve Growth Factor (NGF) and its high-affinity receptor tropomyosin receptor kinase A (TRKA) increase their expression during the progression of epithelial ovarian cancer (EOC), promoting cell proliferation and angiogenesis through several oncogenic proteins, such as c-MYC and vascular endothelial growth factor (VEGF). The expression of these proteins is controlled by microRNAs (miRs), such as miR-145, whose dysregulation has been related to cancer. The aims of this work were to evaluate in EOC cells whether NGF/TRKA decreases miR-145 levels, and the effect of miR-145 upregulation. The levels of miR-145-5p were assessed by qPCR in ovarian biopsies and ovarian cell lines (human ovarian surface epithelial cells (HOSE), A2780 and SKOV3) stimulated with NGF. Overexpression of miR-145 in ovarian cells was used to evaluate cell proliferation, migration, invasion, c-MYC and VEGF protein levels, as well as tumor formation and metastasis in vivo. In EOC samples, miR-145-5p levels were lower than in epithelial ovarian tumors. Overexpression of miR-145 decreased cell proliferation, migration and invasion of EOC cells, changes that were concomitant with the decrease in c-MYC and VEGF protein levels. We observed decreased tumor formation and suppressed metastasis behavior in mice injected with EOC cells that overexpressed miR-145. As expected, ovarian cell lines stimulated with NGF diminished miR-145-5p transcription and abundance. These results suggest that the tumoral effects of NGF/TRKA depend on the regulation of miR-145-5p levels in EOC cells, and that its upregulation could be used as a possible therapeutic strategy for EOC.

Polycystic ovary syndrome (PCOS) affects not only ovarian functions but is also able to affect endometrium metabolism. Around 80% of women with PCOS are obese. High tumor necrosis factor (TNF)-α production and low adiponectin levels are characteristics of obesity. Interestingly, endometrium from obese women with PCOS presents an insulin-resistance condition, high TNF-α levels, and low adiponectin levels. However, TNF-α effect on molecules associated with insulin action in endometrial cells remains unclear. Therefore, the objective of this work was to evaluate TNF-α effect on expression of molecules associated with adiponectin (insulin sensitizing) and TNF-α signaling pathways and on Glucose Transporter type 4 (GLUT-4) levels in human endometrial cells under the characteristic conditions of hyperandrogenic/hyperinsulinic (HA/HI) PCOS. Two human endometrial stromal cell lines (T-HESC/St-T1b) under HA/HI conditions were used to assay the effect of high TNF-α concentration (100 ng/mL) on adiponectin, AdipoR1-AdipoR2 receptors, Adaptor protein phosphotyrosine interacting with PH domain and leucine zipper 1 (APPL1), Phospho-AMP-activated protein kinase T172 (p-AMPKT172), GLUT-4, Tumor necrosis factor receptor 1 (TNFR1)-Tumor necrosis factor receptor 2 (TNFR2) receptors protein levels, and nuclear factor κB (NFκB) nuclear content, by Western blot or immunocytochemistry. The NFκB participation in TNF-α effect on adiponectin expression was assayed using an NFκB inhibitor (pyrrolidine dithiocarbamate). The TNF-α increases the expression of molecules associated with its own signaling pathway ( P < .05) and decreases the protein levels of adiponectin and its associated molecules ( P < .05). Moreover, TNF-α increases NFκB nuclear content ( P < .001), whereas with NFκB inhibition the decrease in adiponectin content induced by TNF-α was not observed. GLUT-4 levels were lower with TNF-α treatment ( P < .01). Thus, in human endometrial stromal cells, high TNF-α levels negatively affect the insulin action through decreased adiponectin signaling and GLUT-4 protein. This could explain the failures observed in endometrial function of obese women with PCOS.

No abstract

The evidences obtained in PCOS-endometria clearly indicate that these molecular defects could partially explain the reproductive failures of these patients.