Mutations in isocitrate dehydrogenase (IDH) are the most prevalent genetic abnormalities in lower grade gliomas. The presence of these mutations in glioma is prognostic for better clinical outcomes with longer patient survival. In the present study, we found that defects in oxidative metabolism and 2-HG production confer chemosensitization in IDH1-mutated glioma cells. In addition, temozolomide (TMZ) treatment induced greater DNA damage and apoptotic changes in mutant glioma cells. The PARP1-associated DNA repair pathway was extensively compromised in mutant cells due to decreased NAD+ availability. Targeting the PARP DNA repair pathway extensively sensitized IDH1-mutated glioma cells to TMZ. Our findings demonstrate a novel molecular mechanism that defines chemosensitivity in IDH-mutated gliomas. Targeting PARP-associated DNA repair may represent a novel therapeutic strategy for gliomas.

Identification of mechanisms underlying endometriosis pathogenesis will facilitate understanding and treatment pf infertility and pain associated with this disorder. Herein, we investigated the expression of steroidogenic pathway enzymes and key decidualization biomarkers, in endometrial tissue and in eutopic endometrial stromal fibroblasts (hESF) from women with vs. without endometriosis and subsequently treated in vitro with 8-Br-cAMP or progesterone (P4). Real-time QPCR, immunohistochemistry, enzyme-linked immunosorbent assay and radiometric aromatase activity assay were used. The results demonstrate significantly increased (14.5-fold, p=0.037) expression of aromatase in eutopic endometrium of women with disease. In 8-Br-cAMP-treated hESF from eutopic endometrium of women with endometriosis, the balance in estradiol (E2) and P4 biosynthetic and metabolizing enzymes is disturbed (decreased HSD3B1 and HSD17B2, and increased HSD17B1 and aromatase), with the equilibrium being shifted towards and E2-enriched milieu. However, hESF from the same group of women treated with P4 did not demonstrate such responsiveness. Lower expression of IGFBP1 and prolactin mRNA and protein was observed in hESF from women with vs. without endometriosis in response to 8-Br-cAMP, but not P4, suggesting a blunted response of these decidual biomarkers to activation of the PKA pathway in eutopic endometrium in women with disease. The dichotomy of 8-Br-cAMP regulation of select steroidogenic enzymes leading to an enriched E2 milieu within the endometrium and a blunted response of decidual biomarkers to this decidualizing agent of hESF from women with endometriosis suggests resistance to full decidualization of the stromal fibroblasts and mechanisms underlying implantation failure and the pathophysiology of this disorder.

BackgroundBisphenol A (BPA), a chemical used as a plasticizer, is a potent endocrine disruptor that, even in low concentrations, disturbs normal development and functions of reproductive organs in different species.ObjectivesWe investigated whether BPA affects human ovarian granulosa cell function.MethodsWe treated KGN granulosa cells and granulosa cells from subjects undergoing in vitro fertilization (IVF) with follicle-stimulating hormone (FSH), BPA, or BPA plus FSH in a dose- and time-dependent manner. We then evaluated expression of insulin-like growth factor 1 (IGF-1), aromatase, and transcription factors known to mediate aromatase induction by FSH [including steroidogenic factor-1 (SF-1), GATA4, cAMP response element binding protein-1 (CREB-1), and peroxisome proliferator–activated receptor-γ (PPARγ)], as well as 17β-estradiol (E2) secretion. KGN cells were transfected with a PPARγ-containing vector, followed by assessment of aromatase and IGF-I expression.ResultsBPA reduced FSH-induced IGF-1 and aromatase expression and E2 secretion in a dose-dependent fashion. Similar effects on aromatase were observed in IVF granulosa cells. SF-1 and GATA4, but not CREB-1, were reduced after BPA treatment, although PPARγ, an inhibitor of aromatase, was significantly up-regulated by BPA in a dose-dependent manner, with simultaneous decrease of aromatase. Overexpression of PPARγ in KGN cells reduced FSH-stimulated aromatase and IGF-1 mRNAs, with increasing concentrations of the transfected expression vector, mimicking BPA action. Also, BPA reduced granulosa cell DNA synthesis without changing DNA fragmentation, suggesting that BPA does not induce apoptosis.ConclusionsOverall, the data demonstrate that BPA induces PPARγ, which mediates down-regulation of FSH-stimulated IGF-1, SF-1, GATA4, aromatase, and E2 in human granulosa cells. These observations support a potential role of altered steroidogenesis and proliferation within the ovarian follicular compartment due to this endocrine disruptor.

Over the past 20 years, the expression, signaling mechanisms, and roles of members of the insulin-like growth factor (IGF) family (ligands, receptors, binding proteins, and binding protein proteases and their inhibitors) have been elucidated in ovarian follicle function in humans and other species. In vitro studies with human, nonhuman primate, and farm animal granulosa and thecal cells and genetic approaches using mouse knockout models for IGF family members have revealed that IGFs are key intraovarian regulators of follicle growth, selection, atresia, cellular differentiation, and steroidogenesis, oocyte maturation, and cumulus expansion. Some of these actions are synergistic with gonadotropins, although most are not sustainable with IGFs alone and require gonadotropin actions, thereby designating IGFs as "co-gonadotropins." In the human disorder of polycystic ovarian syndrome, characterized by small antral follicle arrest, the IGF system appears to contribute to the observed resistance to follicle-stimulating hormone action at the level of the granulosa compartment and the persistence of an androgen-dominant milieu in the arrested follicles. Interestingly, recent studies demonstrate that endocrine-disrupting chemicals can compromise IGF activity and signaling in the ovarian follicle, affecting follicle development, steroidogenesis, and oocyte quality. The successful development of a healthy oocyte and appropriate granulosa and theca cell steroidogenesis on a cyclic basis are contingent on multiple factors, including a properly functioning intraovarian IGF system. Disruption of even one component of this system can lead to abnormal follicular development and function and compromised reproductive capacity.

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