Luteinizing hormone inhibits cisplatin-induced apoptosis in human epithelial ovarian cancer cells

Gynotoxic Effects of Chemotherapy and Potential Protective Mechanisms

Chemotherapy is one of the leading cancer treatments. Unfortunately, its use can contribute to several side effects, including gynotoxic effects in women. Ovarian reserve suppression and estrogen deficiency result in reduced quality of life for cancer patients and are frequently the cause of infertility and early menopause. Classic alkylating cytostatics are among the most toxic chemotherapeutics in this regard. They cause DNA damage in ovarian follicles and the cells they contain, and they can also induce oxidative stress or affect numerous signaling pathways. In vitro tests, animal models, and a few studies among women have investigated the effects of various agents on the protection of the ovarian reserve during classic chemotherapy. In this review article, we focused on the possible beneficial effects of selected hormones (anti-Müllerian hormone, ghrelin, luteinizing hormone, melatonin), agents affecting the activity of apoptotic pathways and modulating gene expression (C1P, S1P, microRNA), and several natural (quercetin, rapamycin, resveratrol) and synthetic compounds (bortezomib, dexrazoxane, goserelin, gonadoliberin analogs, imatinib, metformin, tamoxifen) in preventing gynotoxic effects induced by commonly used cytostatics. The presented line of research appears to provide a promising strategy for protecting and/or improving the ovarian reserve in the studied group of cancer patients. However, well-designed clinical trials are needed to unequivocally assess the effects of these agents on improving hormonal function and fertility in women treated with ovotoxic anticancer drugs.

Whole Genome Transcriptomic Analysis of Ovary Granulosa Cells Revealed an Anti-Apoptosis Regulatory Gene DLGAP5 in Polycystic Ovary Syndrome

The mechanisms underlining pathogenesis of polycystic ovary syndrome (PCOS) remain largely unknown. Dysfunction of ovarian granulosa cells plays an important role. The present study performed the lncRNA and mRNA profiling by whole genome transcriptomic sequencing of ovary granulosa cells from women with PCOS and investigated the potential role of differentially expressed gens (DEGs) in the pathomechanism of PCOS. In total, 1,936 DEGs (30 upregulated and 1,906 downregulated mRNAs and lncRNAs) were identified in the ovary granulosa cells between control and PCOS group. Functional enrichment analysis showed that DEGs were mainly associated with cytokine-cytokine receptor interaction, neuroactive ligand-receptor interaction, and olfactory transduction. qRT-PCR validated the upregulation of DLGAP5 mRNA in ovary from PCOS group when compared to control group. Immunostaining and TUNEL assays showed that DLGAP5 protein level was increased while apoptosis was decreased in follicles of ovary in PCOS group. In vitro functional assays showed that DLGPA5 knockdown repressed viability and proliferation, but enhanced apoptosis and disrupted cell cycle in granulosa cells; while DLGAP5 overexpression had the opposite effects in granulosa cells. In conclusion, the study showed differentially expressed lncRNA and mRNA profile in the granulosa cells in ovaries of PCOS. Functional results demonstrated that DLGAP5 is a dysregulated candidate gene in the pathogenesis of PCOS, especially granulosa cell apoptosis and proliferation.

Effect of luteinizing hormone on goat theca cell apoptosis and steroidogenesis through activation of the PI3K/AKT pathway

Luteinizing hormone (LH) is a glycoprotein that regulates the function of ovarian follicular cells. Theca cells (TCs) also have a key role in follicular growth and atresia. The effects and intracellular signaling mechanisms were investigated of LH on apoptosis and steroidogenesis in goat gonadotropin-independent follicular (1.0-4.0 mm) TCs. The results indicated that LH increased androstenedione secretion and relative abundance of CYP17A1 and BCL2 mRNA in the TCs, whereas LH in combination with LY294002, a PI3K/AKT inhibitor, decreased LH-induced function. The apoptosis ratio and expression of the BAX gene in TCs were less with LH treatment, and the extent of this inhibition was decreased by suppressing the PI3K/AKT pathway. In conclusion, results of the present study indicate LH regulates apoptosis and steroidogenesis in goat TCs by activating the PI3K/AKT pathway.

Luteinizing hormone compromises the in vivo anti-tumor effect of cisplatin on human epithelial ovarian cancer cells

Platinum-based chemotherapy is the most common therapeutic regimen used to treat patients with ovarian cancer. However, the emergence of drug resistance to platinum compromises the clinical success of this treatment. Epithelial ovarian cancer is usually accompanied by an increased level of luteinizing hormone (LH). Therefore, the effect of LH on platinum resistance requires further investigation. In the current study, the effect of cisplatin and/or LH on platinum resistance was examined using the SKOV3ip1 and HeyA8 models. Following therapy, tumors were examined for proliferation (ki67) and apoptosis (cleaved caspase-3). Cisplatin alone and in combination with LH significantly inhibited tumor growth in SKOV3ip1- and HeyA8-implanted mice. Treatment with LH alone had minimal effect in the models. However, treatment with cisplatin combined with LH was less effective than treatment with cisplatin alone. Additionally, ki67 counts were significantly increased and cleaved caspase-3 counts were significantly reduced in mice treated with cisplatin combined with LH compared with mice treated with cisplatin alone. Such results indicate that LH weakens the anti-tumor effect of cisplatin in vivo and that LH may contribute to the development of drug resistance to cisplatin in ovarian cancer.

PDCD5 regulates cell proliferation, cell cycle progression and apoptosis

Programmed cell death (PDCD)5 is cloned from human leukemia cell line TF-1. PDCD5 is one of the members of the programmed cell death protein family that is frequently involved in tumor growth and apoptosis. To investigate the molecular and cellular functions of PDCD5, the present study established a PDCD5 stably overexpressing A431 cell line and examined the role of PDCD5 in cell proliferation, cell cycle progression and apoptosis. The data demonstrated that overexpression of PDCD5 significantly inhibited cell proliferation, induced cell cycle arrest at G2/M phase and apoptosis in A431 cells. The expression profiles of certain key regulators of these cellular events were further investigated, including P53, B cell lymphoma (BCL)-2, BCL-2 associated X protein (BAX) and caspase (CASP)3. The data demonstrated that at the transcript and protein levels, P53, BAX and CASP3 were all upregulated in the PDCD5 stably overexpressing A431 cells whereas BCL-2 was downregulated, indicating that PDCD5 acts as an important upstream regulator of P53, BCL-2, BAX and CASP3. The data suggest that PDCD5 regulates cell proliferation, cell cycle progression and apoptosis in A431 cells. PDCD5 may be a novel tumor suppressor gene, and may be potentially used for cancer treatment in the future.