Repressive effect of the phytoestrogen genistein on estradiol-induced uterine leiomyoma cell proliferation.

OBJECTIVE: Uterine leiomyomas are the most common gynecological benign tumor and greatly affect reproductive health and well-being. They are the predominant indication for hysterectomy in premenopausal women. Current epidemiological study reported that soy products intake is inversely associated with diseases leading to hysterectomy. Genistein is a soy-derived phytoestrogen and its inhibitory effect on leiomyoma cell proliferation is reported. In this study, we investigated the siginificant inhibitory effect of genistein on estradiol (E(2))-induced leiomyoma cells proliferation. STUDY DESIGN: The Eker rat-derived uterine leiomyoma cell line ELT-3 cells were used. Cell proliferation was assessed by counting the number of cells. The expression of estrogen receptors and peroxisome proliferator-activated receptor-gamma (PPARgamma) was evaluated by Western blot analysis. RESULTS: PPARgamma was expressed in ELT-3 cells and genistein acted as PPARgamma ligand. This inhibitory effect of genistein was attenuated by the treatment of cells with PPARgamma antagonist bisphenol A diglycidyl ether (BADGE) or GW9662. CONCLUSION: These experimental findings in vitro show that the repressive effect of genistein on E(2)-induced ELT-3 cell proliferation is through the activation of PPARgamma. Genistein may be useful as an alternative therapy for leiomyoma.

Metal transcription factor-1 is involved in hypoxia-dependent regulation of placenta growth factor in trophoblast-derived cells.

Placenta growth factor (PlGF) is a placental angiogenic factor. Metal-responsive transcription factor (MTF)-1 was reported to take part in the hypoxic induction of PlGF in RAS-transformed mouse fibroblasts. We contrarily showed that PlGF mRNA and protein levels decreased under hypoxia in a choriocarcinoma BeWo cell line derived from trophoblast. In this report, we examined whether hypoxia-dependent regulation of the PlGF gene in these cells also depends on MTF-1. We analyzed the effect of hypoxia on MTF-1 expression, and it was revealed to be decreased. Moreover, MTF-1 small interfering RNA treatment decreased PlGF mRNA level. To investigate the transcription of PlGF under hypoxia, we cloned promoter region of the human PlGF. Promoter deletion analysis suggested that triple repeats of metal-responsive element located between -511 and -468 bp in the promoter are important for the hypoxic regulation of PlGF. Treatment with MTF-1 small interfering RNA resulted in the significant decreased luciferase activity in PlGF reporter constructs. Chromatin immunoprecipitation showed the binding of the MTF-1 protein to the promoter region. We examined MTF-1 immunoreactivity in trophoblasts of term placental tissue from patients with normal pregnancies and preeclampsia, which represents a condition of placental hypoxia. Immunoreactivity of the MTF-1 protein was decreased in placentas from pregnant women with preeclampsia when compared with those from normal pregnant women. Taken together, these findings suggest that MTF-1 is involved in hypoxia-dependent regulation of PlGF in trophoblast-derived cells.

Expression of p21Cip1/Waf1 and p27Kip1 in small cell neuroendocrine carcinoma of the uterine cervix.

Small-cell neuroendocrine carcinoma of the uterine cervix (SCCC), a rare but malignant cervical neoplasm, has a highly aggressive phenotype that requires more intensive treatment than other cervical tumors. Immunohistochemical methods were used to compare the expression of p21Cip1/Waf1 and p27Kip1 in SCCC and squamous cell carcinoma, the most common type of cervical cancer. In SCCC, p21 expression was significantly reduced compared with squamous cell carcinoma, whereas expression of p27 was similar in both carcinomas. Reduced expression of p21 could be a helpful diagnostic marker and may contribute to the invasive phenotype of SCCC.

Relationship between metabolic syndrome and uterine leiomyomas: a case-control study.

BACKGROUND/AIMS: Uterine leiomyomas are the most common gynecological benign tumor and greatly affect reproductive health and well-being. The pathophysiology and epidemiology of fibroids are poorly understood. Obesity and elevated blood pressure have been reported to be predisposing factors. In this study, we investigated whether fibroids are associated with some criteria of the metabolic syndrome. METHODS: The case patients were 213 women who underwent hysterectomy or myomectomy for fibroids, and the control subjects were 159 women who underwent operation for benign indications other than fibroids. Preoperative information on body mass index (BMI), blood pressure (BP), serum triglyceride (TG) and fasting plasma glucose (FPG) was obtained from medical records. The patients were classified as overweight if they had a preoperatively measured BMI of > or =24.0, hypertensive if BP was > or =140/90 mm Hg, hypertriglyceridemic if TG was > or =150 mg/dl, and hyperglycemic if FPG was > or =110 mg/dl. RESULTS: BMI, BP, TG and FPG were significantly higher in the case group compared with the control group. In logistic regression analysis, fibroids were statistically significantly associated with being overweight and hypertensive. With the combination of these risk factors, the risk of fibroids increased. CONCLUSION: Uterine leiomyomas may share pathogenic features with the development of metabolic syndrome.

Elevated level of plasma vascular endothelial growth factor after gonadotropin-releasing hormone agonist treatment for leiomyomata.

OBJECTIVE: Uterine leiomyomata are the most common gynecological benign tumor and greatly affect reproductive health and well-being. The pathophysiology and epidemiology of fibroids are poorly understood. Gonadotropin-releasing hormone agonist (GnRH-a) pretreatment is one of the unfavourable factors for leiomyomata treatment with uterine artery embolisation (UAE). In this study, we investigated the plasma level of vascular endothelial growth factor (VEGF) in uterine leiomyoma patients with or without GnRH-a pretreatment. STUDY DESIGN: Thirty-two women who underwent UAE for symptomatic uterine leiomyoma were analysed. The plasma level of VEGF was studied before UAE. RESULTS: The level of plasma VEGF was significantly higher in the GnRH-a pretreated group compared with the non-treated group. CONCLUSION: A compensative reaction for vasculature after GnRH-a treatment is speculated. Higher level of VEGF in GnRH-a pretreatment group could be one of the unfavourable factors for the treatment of uterine leiomyomata by UAE.

Dual repressive effect of angiotensin II-type 1 receptor blocker telmisartan on angiotensin II-induced and estradiol-induced uterine leiomyoma cell proliferation.

BACKGROUND: Although uterine leiomyomas or fibroids are the most common gynecological benign tumor and greatly affect reproductive health and well-being, the pathophysiology and epidemiology of uterine leiomyomas are poorly understood. Elevated blood pressure has an independent, positive association with risk for clinically detected uterine leiomyoma. Angiotensin II (Ang II) is a key biological peptide in the renin-angiotensin system that regulates blood pressure. METHODS: In this study, we investigated the potential role of Ang II (1-1000 nM) in the proliferation of rat ELT-3 leiomyoma cells in vitro. RT-PCR and western blot analysis with cell proliferation and DNA transfection assays were performed to determine the mechanism of action of Ang II. RESULTS: Ang II induced ELT-3 leiomyoma cell proliferation (P < 0.01) and the expression of Ang II type 1 receptor (AT(1)R) and AT(2)R mRNA and protein was confirmed. Regarding the intracellular signaling pathway, the Ang II-induced cell proliferation was AT(1)R-, epidermal growth factor receptor-, extracellular-regulated kinase- and protein kinase C-dependent but was not dependent on the AT(2)R or phosphatidylinositol-3 kinase or JAK kinase. The AT(1)R blocker telmisartan, effectively repressed Ang II-induced and estradiol-induced cell proliferation (P < 0.01). AT(1)R, but not AT(2)R, plays a role in Ang II-induced ELT-3 cell proliferation. CONCLUSIONS: These experimental findings in vitro highlight the potential role of Ang II in the proliferation of leiomyoma cells.

ATP-induced hexameric ring structure of the cyanobacterial circadian clock protein KaiC.

BACKGROUND: KaiA, KaiB and KaiC are cyanobacterial circadian clock proteins. KaiC contains two ATP/GTP-binding Walker's motif As, and mutations in these regions affect the clock oscillations. RESULTS: ATP induced the hexamerization of KaiC. The Km value for the ATP for the hexamerization was 1.9 micro m. Triphosphate nucleotides bound to the two Walker's motif As, and their binding functioned cooperatively for the hexamerization. An unhydrolysable substrate, 5'-adenylylimidodiphosphate (AMPPNP), also induced the hexamerization, indicating that nucleotide binding, but not its hydrolysis, is essential for the hexamerization. Mutations in each of the two Walker's motif As that affect the clock phenotype increased the Km value for ATP and inhibited the hexamerization. Thus, the KaiC hexamerization seems to be necessary for its clock function. The KaiC hexamer has the shape of a hexagonal pot with a diameter and height of approximately 100 A and with a relatively large cavity (73 A deep and 18-34 A wide) inside. This pot-shaped structure suggests that KaiC functions in a similar manner to F1-ATPase, helicase or ATP-dependent protease/chaperon, all of which have dynamic activities inside the central cavity of their hexameric rings. CONCLUSION: ATP-induced KaiC hexamerization is necessary for the clock function of KaiC.