ABSTRACT
Obesity is an established risk factor for endometrial cancer. Leptin, a secreted protein of the ob gene by white adipose tissue, plays an important role in the regulation of food intake and energy consumption in the brain and acts as a potential growth stimulator in normal and neoplastic cancer cells. However, a direct role for leptin in endometrial cancer has not been demonstrated. In the present study, the effect of leptin on the proliferation of Ishikawa endometrial cancer cells was investigated as well as the possible mechanism(s) underlying this action in endometrial cancers which express both short and long isoforms of leptin receptors. The expression of leptin receptor (ObRb) in Ishikawa cells was detected by RT-PCR and Western blotting. The cells after serum starvation, were treated by leptin with various concentrations (0, 10, 50, 100, 150 ng/mL) for different durations (6, 12, 24 h). The effect of leptin treatment on cell proliferation was examined by MTT assay. Meanwhile, inhibitory effect of Janus tyrosine kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) inhibitor AG490 or extracellular signal-regulated kinase 1/2 (ERK1/2) inhibitor PD98059 on the proliferation of Ishikawa cells induced by leptin was also studied. Ishikawa cells were treated with 100 ng/mL leptin for various periods (0, 20, 40, 60 min), and the levels of STAT3 phosphorylation and ERK1/2 phosphorylation were examined by Western blotting. The results showed that leptin induced the phosphorylation of STAT3 and the activation of ERK1/2 in a time- and dose-dependent manner in the Ishikawa endometrial cancer cells. Blocking STAT3 phosphorylation with the inhibitor AG490, or blocking ERK1/2 activation by the specific ERK1/2 kinase inhibitor, PD98059, abolished leptin-induced proliferation of Ishikawa cells. In addition, leptin was found to potently induce the invasion of endometrial cancer cells in a Matrigel invasion assay. Leptin-stimulated invasion was effectively blocked by pharmacological inhibitors of STAT3 (AG490) and ERK1/2 kinase (PD98059). These results suggested that leptin promotes endometrial cancer growth and invasiveness by activating STAT3 and ERK1/2 signaling pathways and therefore blocking its action at the receptor level can be a rational therapeutic strategy.
ABSTRACT
To investigate the expression of mRNA of leptin long-form receptor (OB-Rb) in luteinized granulosa cells of obese women with polycystic ovary syndrome (PCOS), and to determine the role of leptin in the physiopathology of PCOS, luteinized granulosa cells were collected from the follicle fluid of 10 obese women who met the diagnostic criteria for PCOS and their BMI was equal to or greater than 25 kg/m2, and at the same time, granulosa cells were collected from 10 normal women undergoing IVF-ET who served as the control group. Some luteinized granulosa cells were taken from normal women for in-vitro culture, into which human leptin of different concentrations was added (0, 10, 100 and 1000 ng/mL). After stimulation with leptin for 48 h, RT-PCR was employed for the detection of the expression of OB-RLmRNA in the luteinized granulosa cells. Our results showed that the level of OB-RLmRNA in luteinized granulosa cells of obese PCOS women was higher than those in the control (P＜0.05). In luteinized granulosa cells cultured in vitro and stimulated by human leptin for 48 h, the level of OB-RLmRNA was higher than those without leptin stimulation (P＜0.01), and when leptin concentration was at 100 ng/mL, and the level of OB-RLmRNA reached a peak. It is concluded that in obese PCOS women, the level of serum leptin is increased, which promotes the expression of OB-RL in luteinized granulosa cells and increases the sensitivity of the granulosa cells to leptin. Leptin may contribute to anovulation in obese women with PCOS.
ABSTRACT
In order to explore the effects of metformin combined with cyproterone acetate (CPA) on the clinical features, endocrine and metabolism of the patients with polycystic ovarian syndrome (PCOS), 50 cases of non-obese PCOS were randomly subjected to CPA (CPA treatment group, n = 25) and CPA+ metformin (n = 25) treatment for 6 months. Before and after treatment the body mass index (BMI), waist : hip ratio (WHR), ovarian volume, serum gonadotrophin, androgen and sex hormone-binding globulin (SHBG) levels, and fasting lipid, glucose and insulin levels were measured. The results showed that all of the parameters in two groups were similar before treatment. After treatment for 6 months in the CPA+ metformin group, BMI and WHR were significantly decreased, while insulin sensitivity was significantly decreased as Compared with those before treatment. In CPA group, no significant changes were found before and after treatment. Combined use of CPA and metformin could result in the reduction of serum androstenedione and increases of serum SHBG levels as compared with the CPA treatment alone. It was concluded that combined use of CPA and metformin could improve the insulin sensitivity, and further suppress the hyperandrogenism in non-obese women with PCOS.
Subject(s)
Androgen Antagonists/therapeutic use , Androstenedione/blood , Body Mass Index , Cyproterone Acetate/therapeutic use , Drug Therapy, Combination , Hypoglycemic Agents/therapeutic use , Insulin Resistance , Metformin/therapeutic use , Polycystic Ovary Syndrome/drug therapyABSTRACT
In order to explore the effects of metformin combined with cyproterone acetate (CPA) on the clinical features, endocrine and metabolism of the patients with polycystic ovarian syndrome (PCOS), 50 cases of non-obese PCOS were randomly subjected to CPA (CPA treatment group, n=25) and CPA+metformin (n= 25) treatment for 6 months. Before and after treatment the body mass index (BMI), waist: hip ratio (WHR), ovarian volume, serum gonadotrophin, androgen and sex hormone-binding globulin (SHBG) levels, and fasting lipid, glucose and insulin levels were measured. The results showed that all of the parameters in two groups were similar before treatment. After treatment for 6 months in the CPA+ metformin group, BMI and WHR were significantly decreased, while insulin sensitivity was significantly decreased as compared with those before treatment. In CPA group, no significant changes were found before and after treatment. Combined use of CPA and metformin could result in the reduction of serum androstenedione and increases of serum SHBG levels as compared with the CPA treatment alone. It was concluded that combined use of CPA and metformin could improve the insulin sensitivity, and further suppress the hyperandrogenism in non-obese women with PCOS.
ABSTRACT
In order to investigate the mechanism of elevated vascular endothelial growth factor (VEGF) in peritoneal fluids from patients with endometriosis, macrophages were recovered from peritoneal fluids obtained at the time of diagnostic laparoscopy from infertile women with endometriosis (EMT group, n=20) and without endometriosis (control group, n=20). Macrophages were cultured in vitro. The VEGF levels of peritoneal fluid and the supernatant of macrophages culture were determined by enzyme linked immunoassay (ELISA). Meanwhile, the eutopic (n=20) and ectopic endometrium (n=20) from endometriosis patients, and normal edometrium (n=20) from non-endometriosis patients were obtained for the analysis of VEGF expression by labeled Streptavidin Biotin (LSAB). It was found that VEGF levels in peritoneal fluid and macrophages culture supernatant were significantly higher in EMT group than in control group (P<0.01). In normal endometrium, VEGF showed a cyclic changes and similar in eutopic and ectopic endometrium from patients with endometriosis. There was no difference in the intensity of VEGF in endometrium between two groups within each menstrual phase. It is suggested that altered VEGF production by peritoneal macrophages and ectopic endometrium secretion may contribute to the elevated VEGF levels in the peritoneal fluid of patients with endometriosis.
Subject(s)
Adult , Female , Humans , Ascitic Fluid , Metabolism , Cells, Cultured , Endometriosis , Metabolism , Macrophages, Peritoneal , Pathology , Vascular Endothelial Growth Factor AABSTRACT
The effect of rosiglitazone on endocrine, metabolism and ovulatory performance in the paitents with polycystic ovary syndrome (PCOS) and insulin resistance was investigated. Twenty-five patients diagnosed as having polycystic ovary syndrome (PCOS) combined with insulin resistance were treated with rosiglitazone for 12 weeks. Before and after treatment, serum luteinizing hormone (LH), follicle stimulating hormone (FSH), estradiol (E2), testosterone (T), androstenedione (A), sex hormone binding globulin (SHBG), insulin and glucose concentration, total cholesterol, triglycerides (TG), high density lipoprotein-cholesterol (HDL-C), low density lipoprotein-cholestero (LDL-C), apolipoprotein A, apolipoprotein B levels and ovulatory performance were determined. The results showed that after treatment serum insulin levels was decreased significantly (P<0.01). The HDL-C was increased while LDL-C decreased significantly (P<0.05, P< 0.01). The serum LH, T, A concentrations and the ratio of LH/FSH were decreased, while SH-BG levels increased significantly (P<0.01). The ovulation rate during clomiphene citrate therapy was 72%, significantly higher than that before treatment. It is likely that reduction of hyperinsulinemia that is produce by rosiglitazone may effectively improve the endocrine, metabolism and ovulatory performance in the patients with PCOS and insulin resistance.
Subject(s)
Adult , Female , Humans , Estradiol , Blood , Follicle Stimulating Hormone , Blood , Hypoglycemic Agents , Therapeutic Uses , Insulin Resistance , Luteinizing Hormone , Blood , Ovulation Induction , Polycystic Ovary Syndrome , Drug Therapy , Thiazolidinediones , Therapeutic UsesABSTRACT
In order to investigate the mechanism of elevated vascular endothelial growth factor (VEGF) in peritoneal fluids from patients with endometriosis, macrophages were recovered from peritoneal fluids obtained at the time of diagnostic laparoscopy from infertile women with endometriosis (EMT group, n=20) and without endometriosis (control group, n=20). Macrophages were cultured in vitro. The VEGF levels of peritoneal fluid and the supernatant of macrophages culture were determined by enzyme linked immunoassay (ELISA). Meanwhile, the eutopic (n=20) and ectopic endometrium (n=20) from endometriosis patients, and normal edometrium (n=20) from non-endometriosis patients were obtained for the analysis of VEGF expression by labeled Streptavidin Biotin (LSAB). It was found that VEGF levels in peritoneal fluid and macrophages culture supernatant were significantly higher in EMT group than in control group (P<0.01). In normal endometrium, VEGF showed a cyclic changes and similar in eutopic and ectopic endometrium from patients with endometriosis. There was no difference in the intensity of VEGF in endometrium between two groups within each menstrual phase. It is suggested that altered VEGF production by peritoneal macrophages and ectopic endometrium secretion may contribute to the elevated VEGF levels in the peritoneal fluid of patients with endometriosis.