Proliferation Of Uterine Leiomyoma Cells Research Articles

Transcription Factor KLF11 Integrates Progesterone Receptor Signaling and Proliferation in Uterine Leiomyoma Cells

Uterine leiomyoma is the most common tumor of the female genital tract and the leading cause of hysterectomy. Although progesterone stimulates the proliferation of uterine leiomyoma cells, the mechanism of progesterone action is not well understood. We used chromatin immunoprecipitation (ChIP)-cloning approach to identify progesterone receptor (PR) target genes in primary uterine leiomyoma smooth muscle cells. We identified 18 novel PR-binding sites, one of which was located 20.5 kb upstream of the transcriptional start site of the Krüppel-like transcription factor 11 (KLF11) gene. KLF11 mRNA levels were minimally downregulated by progesterone but robustly upregulated by the progesterone antagonist RU486. Luciferase reporter assays showed significant baseline and RU486-inducible promoter activity in the KLF11 basal promoter or distal PR-binding region, both of which contained multiple Sp1-binding sequences but lacked classic progesterone response elements. RU486 stimulated recruitment of Sp1, RNA polymerase II, PR, and the coactivators SRC-1 and SRC-2 to the distal region and basal promoter. siRNA knockdown of PR increased KLF11 expression, whereas knockdown of KLF11 increased leiomyoma cell proliferation and abolished the antiproliferative effect of RU486. In vivo, KLF11 expression was significantly lower in leiomyoma tissues compared with adjacent myometrial tissues. Taken together, using a ChIP-cloning approach, we uncovered KLF11 as an integrator of PR signaling and proliferation in uterine leiomyoma cells.

Green tea extract inhibits proliferation of uterine leiomyoma cells in vitro and in nude mice

The purpose of this study was to investigate the effect of epigallocatechin gallate (EGCG) on rat leiomyoma (ELT3) cells in vitro and in a nude mice model. ELT3 cells were treated with various concentrations of EGCG. Cell proliferation, proliferation cell nuclear antigen (PCNA), and cyclin-dependent kinase 4 (Cdk4) protein levels were evaluated. ELT3 cells were inoculated subcutaneously in female athymic nude mice. Animals were fed 1.25 mg EGCG (in drinking water)/mouse/day. Tumors were collected and evaluated at 4 and 8 weeks after the treatment. Inhibitory effect of EGCG (200 micromol/L) on ELT3 cells was observed after 24 hours of treatment (P < .05). At > or = 50 micromol/L, EGCG significantly decreased PCNA and Cdk4 protein levels (P < .05). In vivo, EGCG treatment dramatically reduced the volume and weight of tumors at 4 and 8 weeks after the treatment (P < .05). The PCNA and Cdk4 protein levels were significantly reduced in the EGCG-treated group (P < .05). EGCG effectively inhibits proliferation and induces apoptosis in rat ELT3 uterine leiomyoma cells in vitro and in vivo.

Green tea extract inhibits proliferation of uterine leiomyoma cells in vitro and in nude mice

Green tea extract inhibits proliferation of uterine leiomyoma cells in vitro and in nude mice

Uterine Leiomyomata in Relation to Insulin-like Growth Factor-I, Insulin, and Diabetes

Insulin-like growth factor-I (IGF-I) and insulin stimulate cell proliferation in uterine leiomyoma (fibroid) tissue. We hypothesized that circulating levels of these proteins would be associated with increased prevalence and size of uterine fibroids. Participants were 35-49-year-old, randomly selected members of an urban health plan who were enrolled in the study in 1996-1999. Premenopausal participants were screened for fibroids with ultrasound. Fasting blood samples were collected. Associations between fibroids and diabetes, plasma IGF-I, IGF binding protein 3 (BP3), and insulin were evaluated for blacks (n = 585) and whites (n = 403) by using multiple logistic regression. IGF-I showed no association with fibroids in blacks, but in whites the adjusted odds ratios (aORs) for both mid and upper tertiles compared with the lowest tertile were 0.6 (95% confidence intervals [CI] = 0.3-1.0 and 0.4-1.1, respectively). Insulin and diabetes both tended to be inversely associated with fibroids in blacks. The insulin association was with large fibroids; aOR for the upper insulin tertile relative to the lowest was 0.4 (0.2-0.9). The aOR for diabetes was 0.5 (0.2-1.0). Associations of insulin and diabetes with fibroids were weak for whites. Binding protein 3 showed no association with fibroids. Contrary to our hypothesis, high circulating IGF-I and insulin were not related to increased fibroid prevalence. Instead, there was suggestion of the opposite. The inverse association with diabetes, although based on small numbers, is consistent with previously reported findings. Future studies might investigate vascular dysfunction as a mediator between hyperinsulinemia or diabetes and possible reduced risk of fibroids.

Effect of letrozole on the proliferation of uterine leiomyoma cells in vitro.

Objective To investigate the expression of aromatase cytochrome P450 (P450arom), the secretion of estradiol and the suppressive effect of aromatase inhibitor letrozole on the proliferation of uterine leiomyoma cells in vitro. Methods Uterine leiomyoma cells were cultured in vitro, after the action of letrozole with different concentration, MTT was used to examine the proliferative activity of uterine leiomyoma cells, RT-PCR and immunocytochemistry was used to determine the expression of the P450arom protein and mRNA, and the concentration of estradiol in media supernatant was measured by radioimmunity. Results Low dosage (0.06 μmol/L) of letrozole had no effect on the expression of P450arom protein and mRNA, and estradiol synthesis in uterine leiomyoma cell (P>0.05). However, high dosage(0,6-6 μmol/L) of letrozole could down-regulate the expression of P450arom, and to inhibit estradiol synthesis and the proliferation activity of uterine leiomyoma cells(P<0.05). Furthermore, the inhibition were shown to decline gradually along with the increase in the concentrations of letrozole. Conclusion The aromatase inhibitor letrozole could suppress the proliferation of uterine leiomyoma cells in the dosage-dependent manner by down-regulating the expression of the P450arom and decreasing the estradiol synthesis, suggesting that the drug may possibly be effective in the clinical treatment of uterine leiomyoma. Key words: Uterine neoplasms; Letrozole; Aromatase; Estradiol

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 (E2)-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-γ (PPARγ) was evaluated by Western blot analysis.Results. PPARγ was expressed in ELT-3 cells and genistein acted as PPARγ ligand. This inhibitory effect of genistein was attenuated by the treatment of cells with PPARγ antagonist bisphenol A diglycidyl ether (BADGE) or GW9662.Conclusion. These experimental findings in vitro show that the repressive effect of genistein on E2-induced ELT-3 cell proliferation is through the activation of PPARγ. Genistein may be useful as an alternative therapy for leiomyoma.

Induction of Growth Inhibition and Apoptosis in Human Uterine Leiomyoma Cells by Isoliquiritigenin

Isoliquiritigenin(ISL), a calchone flavonoid, has cancer-preventing properties and is often used in Chinese medicine. In the present study, the authors use ISL to determine its effect on cell proliferation and cell cycle progression in primary cultured human uterine leiomyoma cells. Cell viability and cell proliferation assays were conducted. Flow cytometry, annexin V apoptosis assay, and DNA fragmentation assay were performed to determine the effect of ISL on cell cycle and apoptosis. The expression of cell cycle regulatory-related proteins was evaluated by Western blot. The cell viability and proliferation of uterine leiomyoma cells were significantly reduced by ISL treatment in a dose-dependent manner. Flow cytometry results showed that ISL induced subG1 and G2/M arrest. DNA fragmentation assay and annexin V apoptosis assays revealed apoptosis induction. ISL-induced growth inhibition in uterine leiomyoma cells was associated with increased p21(Cip1/) Waf1 expression in a p53-dependent manner. Activation of caspase-3 and downregulation of Bcl-2, cdk 2/4, and E2F, with a concomitant increase in dephosphorylation of Rb and poly-ADP-ribose polymerase cleavage, were observed. This study demonstrates that ISL inhibits cell proliferation by initiating apoptosis in human uterine leiomyoma cells coupled with increased cell cycle arrest. These results indicate that ISL could prove to be a promising chemopreventive and therapeutic agent against human uterine leiomyoma.

Curcumin, a nutritional supplement with antineoplastic activity, enhances leiomyoma cell apoptosis and decreases fibronectin expression

To determine if curcumin has an antiproliferative effect on leiomyoma cells via apoptosis induction and whether curcumin impacts extracellular matrix (ECM) production by assessing the fibronectin expression in leiomyoma cells treated with curcumin. Tissue culture study of immortalized human leiomyoma and patient-matched myometrial cells treated with curcumin. University hospital. Immortalized leiomyoma and myometrial cells from patients with symptomatic leiomyomata. Tissue culture, followed by proliferation studies, RNA, and protein analysis. Cell proliferation, alteration in apoptotic signaling pathways. Curcumin demonstrated an antiproliferative effect on leiomyoma cell lines (IC50 = 20 muM). Importantly, no statistically significant inhibition of growth was observed when patient-matched myometrial cells were exposed to equivalent concentrations of curcumin. Curcumin stimulated caspase-3 and caspase-9 expression while inhibiting extracellular signal-regulated kinase 1 (ERK 1), ERK 2, and nuclear factor kappa B (NF-kappaB), suggesting regulation of leiomyocyte apoptosis. Finally, curcumin inhibited expression of fibronectin in leiomyoma cells. Our findings demonstrate that curcumin inhibited uterine leiomyoma cell proliferation via regulation of the apoptotic pathway, and inhibited production of the ECM component fibronectin. Curcumin provides a novel direction for leiomyoma therapies.

Role of lysophosphatidic acid in the regulation of uterine leiomyoma cell proliferation by phospholipase D and autotaxin

Phospholipase D (PLD) hydrolyzes phosphatidylcholine into phosphatidic acid (PA), a lipidic mediator that may act directly on cellular proteins or may be metabolized into lysophosphatidic acid (LPA). We previously showed that PLD contributed to the mitogenic effect of endothelin-1 (ET-1) in a leiomyoma cell line (ELT3 cells). In this work, we tested the ability of exogenous PA and PLD from Streptomyces chromofuscus (scPLD) to reproduce the effect of endogenous PLD in ELT3 cells and the possibility that these agents acted through LPA formation. We found that PA, scPLD, and LPA stimulated thymidine incorporation. LPA and scPLD induced extracellular signal-regulated kinase (ERK(1/2)) mitogen-activated protein kinase activation. Using Ki16425, an LPA(1)/LPA(3) receptor antagonist and small interfering RNA targeting LPA(1) receptor, we demonstrated that scPLD acted through LPA production and LPA(1) receptor activation. We found that scPLD induced LPA production by hydrolyzing lysophosphatidylcholine through its lysophospholipase D (lysoPLD) activity. Autotaxin (ATX), a naturally occurring lysoPLD, reproduced the effects of scPLD. By contrast, endogenous PLD stimulated by ET-1 failed to produce LPA. These results demonstrate that scPLD stimulated ELT3 cell proliferation by an LPA-dependent mechanism, different from that triggered by endogenous PLD. These data suggest that in vivo, an extracellular lysoPLD such as ATX may participate in leiomyoma growth through local LPA formation.

Differential Expression of Receptor Tyrosine Kinases (RTKs) and IGF-I Pathway Activation in Human Uterine Leiomyomas

Uterine leiomyomas (fibroids) are benign tumors that are prevalent in women of reproductive age. Research suggests that activated receptor tyrosine kinases (RTKs) play an important role in the enhanced proliferation observed in fibroids. In this study, a phospho-RTK array technique was used to detect RTK activity in leiomyomas compared with myometrial tissue. We found that fifteen out of seventeen RTKs evaluated in this study were highly expressed (P < 0.02-0.03) in the leiomyomas, and included the IGF-I/IGF-IR, EGF/EGFR, FGF/FGF-R, HGF/HGF-R, and PDGF/PDGF-R gene families. Due to the higher protein levels of IGF-IR observed in leiomyomas by us in earlier studies, we decided to focus on the activation of the IGF-IR, its downstream effectors, and MAPKp44/42 to confirm our earlier findings; and validate the significance of the increased IGF-IR phosphorylation observed by RTK array analysis in this study. We used immunolocalization, western blot, or immunoprecipitation studies and confirmed that leiomyomas overexpressed IGF-IRbeta and phosphorylated IGF-IRbeta. Additionally, we showed that the downstream effectors, Shc, Grb2, and MAPKp44/42 (P < 0.02-0.001) were also overexpressed and involved in IGF-IR signaling in these tumors, while IRS-I, PI3K, and AKT were not. In vitro studies showed that IGF-I (100 ng/mL) increased the proliferation of uterine leiomyoma cells (UtLM) (P < 0.0001), and that phosphorylated IGF-IRbeta, Shc, and MAPKp44/42 were also overexpressed in IGF-I-treated UtLM cells (P < 0.05), similar to the tissue findings. A neutralizing antibody against the IGF-IRbeta blocked these effects. These data indicate that overexpression of RTKs and, in particular, activation of the IGF-IR signaling pathway through Shc/Grb2/MAPK are important in mediating uterine leiomyoma growth. These data may provide new anti-tumor targets for noninvasive treatment of fibroids.

Cyclin-Dependent Kinase Inhibitor p27Kip1Controls Growth and Cell Cycle Progression in Human Uterine Leiomyoma

The molecular mechanism of the cell-cycle machinery in uterine leiomyoma has not yet been fully elucidated. Among the various types of cell-cycle regulators, p27Kip1 (p27) is considered to be a potent tumor suppressor. To provide further molecular basis for understanding the progression of uterine leiomyoma, our objective was to evaluate the expression level of p27 in normal myometrium and uterine leiomyoma tissue and its effect on cytogenic growth. Western blot analysis, real-time polymerase chain reaction (PCR) and immunohistochemical staining revealed that p27 protein and messenger RNA were down-regulated in uterine leiomyoma tissue and cultured cells compared to normal myometerium. Full-length human p27 cDNA was transferred using a replication-deficient recombinant adenoviral vector (Ad.p27) into uterine leiomyoma cells and evaluated the effect on cell proliferation. Transfection of Ad.p27 into uterine leiomyoma cells resulted in the induction of apoptosis, reduction in viability and proliferation of uterine leiomyoma cells. Our results suggest a new paradigm that down-regulated p27 protein expression is the possible underlying mechanism for the growth of uterine leiomyoma and over-expression of p27 induces cell death. This study provides better understanding of the control exerted by p27 in regulating growth and disease progression of uterine leiomyoma.

Growth inhibition and apoptosis induced in human leiomyoma cells by treatment with the PPAR gamma ligand ciglitizone

The nuclear receptors PPARs (peroxisome proliferator-activated receptors) are transcription factors that play important roles in multiple disease conditions. The activation of PPARs by specific ligands is associated with growth suppression of several different types of human cancer, but the molecular mechanism responsible for this growth suppressive effect remains elusive. The aim of this study was to determine the distribution of PPARgamma protein/mRNA expression in uterine leiomyomas and to identify the PPARgamma induced signaling pathways responsible for the growth inhibition induced by treatment with ciglitizone, a synthetic ligand of PPARgamma, in view of identifying targets that could possibly affect the viability and proliferation of uterine leiomyoma cells. Dose-response studies on proliferation found that uterine leiomyoma was more sensitive to inhibition by ciglitizone treatments than normal myometrium. We also found that ciglitizone significantly stimulated gene expression driven by a PPAR-responsive element in cultured leiomyoma cells and reduced the survival of leiomyoma cells relative to the control cells. The reduced survival of ciglitizone treated leiomyoma cells resulted from a mechanism that involved the Fas receptor-mediated apoptosis signaling cascade. These results suggest that uterine leiomyomas growth and differentiation might be modulated through PPARgamma receptors and that PPARgamma ligands may be of potential use for uterine leiomyoma treatment.

Stimulatory and inhibitory effects of genistein on human uterine leiomyoma cell proliferation are influenced by the concentration

Due to dietary exposure of women to genistein, a soy-derived phytoestrogen, and the estrogen responsiveness of uterine leiomyomas 'fibroids', we evaluated the effects of genistein (0.001-50 microg/ml) on human uterine leiomyoma (UtLM) cells versus uterine smooth muscle cells (UtSMCs) in vitro. Light microscopy was used to determine the effects of genistein on cell morphology. Proliferation was assessed using a colorimetric assay and proliferating cell nuclear antigen (PCNA) immunocytochemistry. Flow cytometry was used to quantitate cells in the S-phase and those undergoing apoptosis. A fluorometric assay and confocal microscopy were used to detect caspase-3 activity and apoptotic bodies, respectively. In UtLM cells, low concentrations (< or = 1 microg/ml) of genistein stimulated proliferation, increased PCNA labeling and the percentage of cells in the S-phase, but this did not occur in UtSMCs. Higher concentrations (> or = 10 microg/ml) of genistein adversely affected the morphology, significantly inhibited proliferation, decreased PCNA labeling, increased caspase-3 activity and induced apoptosis in both cell types. Genistein's effects are concentration-dependent in both cell lines. Lower concentrations elicit proliferative effects on UtLM cells only; whereas, higher concentrations alter morphology, inhibit proliferation, and increase caspase activity and apoptosis in both cell types, with the latter two effects being more extensive in UtSMCs.

Requirements of phosphatidylinositol-3 kinase and mammalian target of rapamycin for estrogen-induced proliferation in uterine leiomyoma- and myometrium-derived cell lines

This study was undertaken to investigate the effects of 17beta-estradiol (E2) on G1 cell cycle progression and proliferation in uterine fibroid and myometrial cells and the roles of phosphatidylinositol-3 kinase and mammalian target of rapamycin in mediating these estrogen effects. The human uterine smooth muscle-derived cells (UtSM) and uterine leiomyoma-derived cells (UtLM) were treated with varying doses of E2 with or without pretreatment with LY294002, a phosphatidylinositol-3 kinase inhibitor, or rapamycin, a mammalian target of rapamycin inhibitor. The effects of E2 on cell cycle progression and proliferation and the roles of phosphatidylinositol-3 kinase and mammalian target of rapamycin in E2-induced effects were studied. Compared with controls, E2 significantly induced G1 cell cycle progression and proliferation in uterine smooth muscle-derived cells and uterine leiomyoma-derived cells. These effects, however, were significantly blocked when LY294002 or rapamycin was used. E2 significantly induces G1 cell cycle progression and cell proliferation in uterine smooth muscle-derived cells and uterine leiomyoma-derived cells, in which phosphatidylinositol-3 kinase and mammalian target of rapamycin are essentially required.

Selective Progesterone Receptor Modulator Asoprisnil (J867) Inhibits Proliferation and Induces Apoptosis in Cultured Uterine Leiomyoma Cells But Not in Cultured Normal Myometrial Cells

It has been demonstrated that progesterone takes a vital role in regulating uterine leiomyoma cell proliferation and apoptosis through up-regulating PCNA and Bcl-2 protein expression and down-regulating TNFα expression in those cells (J Clin Endocrinol Metab 82: 293-299, 83: 2192-2198, 86: 2275-2280). Thus, the present study was conducted to evaluate the effects of the selective progesterone receptor modulator asoprisnil on proliferative activity and apoptosis in cultured uterine leiomyoma cells in comparison with the effects in cultured normal myometrial cells.

Ciglitizone inhibits cell proliferation in human uterine leiomyoma via activation of store-operated Ca2+ channels.

This study investigated the acute effects of a peroxisome proliferator-activated receptor (PPAR)-gamma ligand, ciglitizone, on cell proliferation and intracellular Ca2+ signaling in human normal myometrium and uterine leiomyoma. Changes in intracellular Ca2+ concentration ([Ca2+]i) were measured with fura-2 AM, and cellular viabilities were determined by viable cell count and 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide reduction assay. Ciglitizone (100 microM) induced greater inhibition of cell proliferation in uterine leiomyoma than in myometrium. Ciglitizone also dose-dependently increased [Ca2+]i in both myometrium and uterine leiomyoma; these [Ca2+]i increases were inhibited by PPAR-gamma antagonists and raloxifene. Ciglitizone-induced [Ca2+]i increase showed only an initial peak in normal myometrial cells, whereas in uterine leiomyoma there was a second sustained [Ca2+]i increase as well. The initial [Ca2+]i increase in both myometrium and uterine leiomyoma resulted from the release of Ca2+ by the sarcoplasmic reticulum via activation of ryanodine receptors. The second [Ca2+]i increase was observed only in uterine leiomyoma because of a Ca2+ influx via an activation of store-operated Ca2+ channels (SOCCs). Cell proliferation was inhibited and secondary [Ca2+]i increase in uterine leiomyoma was attenuated by cotreatment of ciglitizone with a SOCC blocker, lanthanum. The results suggest that ciglitizone inhibits cell proliferation and increases [Ca2+]i through the activation of SOCCs, especially in human uterine leiomyoma.

Tranilast inhibits the proliferation of uterine leiomyoma cells in vitro through G1 arrest associated with the induction of p21(waf1) and p53.

Uterine leiomyoma is a mesenchymal tumor composed of smooth muscle cells with fibrous tissues and many mast cells. Tranilast is known to suppress fibrosis or to work as a mast cell stabilizer and is reported to inhibit proliferation of vascular smooth muscle cells. In this study, we examined the effects of tranilast on cultured human leiomyoma cells in vitro to evaluate whether this agent has the potential to inhibit the growth of uterine leiomyomas. Tranilast inhibited the proliferation of cultured leiomyoma cells in a dose-dependent manner without any cytotoxic effect or induction of apoptosis. In association with the inhibitory effect, tranilast induced the cyclin-dependent kinase (CDK) inhibitor p21(waf1) and tumor suppressor gene p53 and decreased CDK2 activity. These results suggest that tranilast arrests the proliferation of uterine leiomyoma cells at the G0/G1 phase, through the suppression of CDK2 activity via an induction of p21(waf1) and p53. Tranilast was concluded to be a potent agent to inhibit proliferative activity of uterine leiomyoma cells.

Transdominant suppression of estrogen receptor signaling by progesterone receptor ligands in uterine leiomyoma cells

Uterine leiomyomas develop in reproductive-age women with high frequency and are dependent on the production of ovarian hormones. While it is generally accepted that these tumors are estrogen (E 2)-responsive, the role of progesterone (P 4) in modulating tumor growth is less clear. In the present study, an in vivo/in vitro rat model was used to characterize progesterone receptor (PR) isoform expression in uterine leiomyoma and investigate PR signaling using progestins and antiprogestins in the leiomyoma-derived cell line ELT-3. PR-A was the predominant isoform expressed in normal myometrium, leiomyomas and ELT3 cells. In the normal myometrium, PR-A and PR-B levels varied during the estrous cycle with low ratios of PR-A relative to PR-B (PR-A/PR-B) coinciding with times of cell proliferation. Although PR ligands had no effect on basal levels of uterine leiomyoma cell proliferation in vitro, both progestins and antiprogestins inhibited E 2-stimulated cell proliferation. In addition, E 2-stimulated transactivation of an estrogen-response-element reporter gene as well as E 2-induced upregulation of the PR were also inhibited by PR ligands. These data indicate that PR ligands can transdominantly suppress estrogen receptor signaling and stimulation of uterine leiomyoma cell growth.

Down-regulation of proliferation and up-regulation of apoptosis by gonadotropin-releasing hormone agonist in cultured uterine leiomyoma cells.

To elucidate the direct effects of gonadotropin-releasing hormone agonist (GnRHa) on the growth of human uterine leiomyoma cells, cell proliferation and apoptosis in cultured leiomyoma cells treated with GnRHa were investigated. Isolated leiomyoma cells were subcultured in DMEM supplemented with 10% FBS for 5 days and stepped down to serum-free conditions for an additional 6 days in the presence or absence of graded concentrations of GnRHa (10(-9) mol/l to 10(-12) mol/l). The effects of GnRHa on the number of viable cells, expression of proliferating cell nuclear antigen (PCNA), Fas and Fas ligand, and apoptosis in cultured leiomyoma cells were examined by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrasodium bromide) assay, immunocytochemical analysis, Western blot analysis and TUNEL assay respectively. RT-PCR was performed to detect the expression of GnRH receptor mRNA in cultured leiomyoma cells. Treatment with GnRHa resulted in a decrease in the number of cultured viable leiomyoma cells assessed by MTT assay in a dose-dependent manner compared with that in control cultures (P<0.01). The growth inhibition of cultured leiomyoma cells treated with GnRHa in concentrations higher than 10(-10) mol/l was associated with the suppression of the proliferative potential characterized by a decrease in PCNA-positive rate of the cultured cells (P<0.01) and an increase in the apoptosis-positive rate assessed by TUNEL assay (P<0.05 and P<0.01). GnRHa markedly increased the expression of Fas and induced the expression of Fas ligand in the cultured leiomyoma cells on the basis of Western blot analysis. These direct effects of GnRHa on the number of viable cultured leiomyoma cells, PCNA-positive rate, apoptosis-positive rate and Fas/Fas ligand expression in the cultured leiomyoma cells were only attained after the 4-day treatment. RT-PCR analysis revealed that GnRH receptor mRNA was expressed in cultured leiomyoma cells. The present results demonstrate that GnRHa directly inhibits the growth of human uterine leiomyoma cells by suppressing cell proliferation and inducing apoptosis, which might be associated with the increase in Fas expression and the induction of Fas ligand expression in the cells.

Effects of Insulin-Like Growth Factors (IGF) and Progesterone (P) on Uterine Leiomyoma and Myometrial Smooth Muscle Cell Proliferation

Objective: Leiomyomas are benign tumors of the smooth muscle cells (SMC) of the uterus that affect at least 50% of women over the age of 30 years. The IGFs (I, II) may play crucial roles in stimulating fibroid SMC proliferation. Likewise, P may also stimulate tumor growth as a greater number of mitoses have been noted in fibroids during the secretory compared with the proliferative phase of the cycle (1). This study aimed to examine the effects of the IGFs alone and in combination with P on fibroid and myometrial SMC proliferation.