trelstar and Endometrial-Neoplasms

The expression of luteinizing hormone-releasing hormone (LHRH) and its receptors has been demonstrated in a number of human malignant tumors, including cancers of the breast, ovary, endometrium and prostate. These findings suggest the presence of an autocrine regulatory system based on LHRH. Recent studies in our laboratory have demonstrated that the function of LHRH produced by ovarian cancer cells is the inhibition of their proliferation. Dose-dependent antiproliferative effects of LHRH-agonists have been observed by several laboratories in cell lines derived from the above cancers. Interestingly, also LHRH-antagonists have marked antiproliferative activity in most of the ovarian, breast and endometrial cancer cell lines tested so far, indicating that the dichotomy of LHRH-agonists/LHRH-antagonists is not valid for the LHRH-system in cancer cells. In addition, our data suggest that the classical LHRH receptor signal transduction mechanisms known from the pituitary (phospholipase-C, protein kinase C, adenylyl cyclase) are not involved in the mediation of LHRH effects in cancer cells. Data obtained by several groups, including ours, rather suggest that LHRH analogs interfere with the signal transduction of growth-factor receptors and related oncogene products associated with tyrosine-kinase activity. The mechanism of action is probably an LHRH-induced activation of a phosphotyrosine phosphatase, counteracting the effects of receptor associated tyrosine kinase. In our hands, LHRH analogs virtually blocked the EGF-induced MAP-kinase activity of ovarian and endometrial cancer cells. The pharmacological exploitation of this mechanism might provide promising new therapies for these cancers.

Topics: Cell Transformation, Neoplastic; Endometrial Neoplasms; Female; Gonadotropin-Releasing Hormone; Humans; Ovarian Neoplasms; Receptors, LHRH; Signal Transduction; Triptorelin Pamoate

The objective of this phase II multicenter study was to assess the efficacy and tolerance of triptorelin (a sustained-release LHRH agonist) in advanced or recurrent endometrial cancer. A total of 101 monthly intramuscular injections were administered to 24 eligible patients (median number/patient = 3; range 1-12). Mainly due to progression, only 16 patients received 3 or more injections. Among the 23 evaluable patients, 1 complete and 1 partial response (response rate of 8.7%) and 5 disease stabilizations were observed, often of long duration, but never in an irradiated area or after progestogens treatment failure. Median survival for eligible patients was 7.2 months (range: 1-36 months). Only grade 1 toxicities possibly related to the treatment were observed in 4 patients. In conclusion, triptorelin was safe, well tolerated, and easily manageable, and the very low toxicity did not impair the quality of life in these patients with a very poor prognosis. Although the response rate was disappointing, several patients showed early evidence of efficacy which may be of long duration. Response rates range between 0 and 45% in different published studies. Additional studies with stricter inclusion criteria and a larger sample size are necessary to better evaluate the role of LHRH agonists in endometrial adenocarcinomas.

Topics: Adult; Aged; Aged, 80 and over; Antineoplastic Agents, Hormonal; Disease Progression; Endometrial Neoplasms; Female; Follicle Stimulating Hormone; France; Humans; Luteinizing Hormone; Middle Aged; Neoplasm Recurrence, Local; Triptorelin Pamoate

This study aims to evaluate the effects and pregnancy outcomes of gonadotropin-releasing hormone agonist (GnRH agonist) combined with aromatase inhibitor (AI) in preserving the fertility of obese women with grade 1 endometrial cancer (EC).. This study recruited obese EC patients who wished to preserve their fertility. The treatment regimen consisted of intramuscular GnRH agonist 3.75 mg every 4 weeks and oral AI 2.5 mg daily. The maintenance regimen was the same as the initial treatment regimen. Primary outcomes included response rate, time to complete response (CR), and time to recurrence; pregnancy outcomes included the time to pregnancy, pregnancy rate and live birth rate.. Six obese patients with EC were included in this study, with the age (mean±standard deviation [SD]) of 30.5±3.3 years and body mass index (mean±SD) of 35.0±1.4 kg/m². CR rate was 100%, and time to CR was 3-6 months. None of the patients had recurrence after a median follow-up of 4.0 years (range, 1.3-7.0 years). The most common side effects were menopause-like symptoms. Among these patients, no weight gain was observed during treatment. The pregnancy rate and live birth rate was 50.0% and 75.0%, respectively, with a median time to pregnancy of 2.4 years (range, 1.0-5.5 years).. The combination of GnRH agonist and AI demonstrated promising long-term effect in young obese EC patients who wished to preserve their fertility. No weight gain side effects were observed. Further studies with a larger sample size are needed to fully evaluate this novel treatment regimen.

Topics: Administration, Oral; Adult; Aromatase Inhibitors; Birth Rate; Endometrial Neoplasms; Female; Fertility Preservation; Gonadotropin-Releasing Hormone; Humans; Injections; Letrozole; Obesity; Pilot Projects; Pregnancy; Triptorelin Pamoate

Type I gonadotropin-releasing hormone (GnRH-I) agonists have been applied for the treatment of steroid-dependent tumors such as breast carcinoma, ovarian cancer and prostatic carcinoma. But the mechanism has not been clarified yet. There are few reports about the treatment of endometrial carcinoma using GnRH-I agonists. Type II GnRH (GnRH-II) is a new subtype of GnRH. Our aim was to investigate the effects of GnRH-I agonists and GnRH-II on estrogen receptor-negative human endometrial carcinoma cells and the effect from phosphatase and tensin homolog gene (PTEN) to them.. A lentiviral vector-mediated RNAi method was used to establish a PTEN-negative HEC-1A cell clone (HEC-1A-ND). MTT and flow cytometry were used to detect the cell proliferation, cell cycle and apoptosis of HEC-1A, HEC-1A-NC and HEC-1A-ND cells after treatment with GnRH-I agonist Triptorelin (10(-11) mol/L to 10(-5) mol/L) or GnRH-II (10(-11) mol/L to 10(-5) mol/L). Western blotting was used to detect AKT and ERK1/2 activation after treatment with different concentrations of Triptorelin or GnRH-II for 30 minutes in the above mentioned three kinds of cells.. Triptorelin and GnRH-II induced apoptosis and inhibited proliferation of HEC-1A, HEC-1A-ND and HEC-1A-NC in a dose-dependent manner. This effect was augmented in HEC-1A-ND cells in which PTEN gene was knocked-down. Furthermore, Triptorelin and GnRH-II inhibited the AKT and ERK activity in HEC-1A-ND cells.. Triptorelin and GnRH-II can promote apoptosis rate and inhibit cell proliferation of estrogen receptor-negative endometrial carcinoma cells in a dose-dependent manner. PTEN gene can inhibit the effects of Triptorelin or GnRH-II on human endometrial carcinoma cells.

Topics: Apoptosis; Blotting, Western; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Endometrial Neoplasms; Female; Gonadotropin-Releasing Hormone; Humans; PTEN Phosphohydrolase; RNA Interference; Triptorelin Pamoate

The aim of the present study was to evaluate the effect of gonadotrophin-releasing hormone agonist (GnRH-a), which is widely used in the medical treatment of symptomatic myomas, on the rate of endometrial cell apoptosis in cultures from women with symptomatic myomas.. The study included 36 women with symptomatic myomas without endometrial hyperplasia or endometrial carcinoma, and 22 controls. Endometrial biopsy specimens were obtained from all subjects. Levels of apoptosis were examined in epithelial endometrial cell cultures before and after incubation with GnRH-a (triptorelin). The percentage of apoptotic cells was evaluated using the terminal deoxynucleotidyl transferase-mediated d-UTP nick end labeling assay and flow cytometry was used to evaluate Annexin V levels.. Levels of spontaneous apoptosis were significantly lower in endometrial cultures from patients with symptomatic myomas than in those from control subjects (P < 0.01). Concentrations as low as 10(-7) M GnRH-a enhanced apoptosis in endometrial cultures from patients with symptomatic myomas (3.48% +/- 0.27% apoptotic cells in untreated samples and 25.45 +/- 0.95% in cells treated with 10(-7) M GnRH-a; P <0.01). The percentage of apoptotic cells also increased when cultures from control women were treated with GnRH-a (8.10 +/- 0.18% in untreated samples and 15.29 +/- 2.30% in treated samples; P <0.01). Levels of apoptosis were dependent on both dose of GnRH-a and time of treatment.. GnRH-a stimulates apoptosis in endometrial cells from patients with symptomatic myomas and this could, at least in part, account for the therapeutic action of GnRH-a.

Topics: Adult; Annexin A5; Antineoplastic Agents, Hormonal; Apoptosis; Biopsy; Endometrial Neoplasms; Female; Flow Cytometry; Gonadotropin-Releasing Hormone; Humans; In Situ Nick-End Labeling; Leiomyoma; Middle Aged; Osmolar Concentration; Time Factors; Triptorelin Pamoate; Tumor Cells, Cultured; Up-Regulation; Uterine Hemorrhage

To study the effect of gonadotropin-releasing hormone-I (GnRH-I) agonist triptorelin and gonadotropin-releasing hormone-II (GnRH-II) on human endometrial carcinoma with different states of PTEN.. The endometrial carcinoma cells (Ishikawa, Ishikawa-PTEN, and Ishikawa-neo) were treated with different concentrations of triptorelin (10(-11) to 10(-5) mol/L) or GnRH-II (10(-11) to 10(-5) mol/L). Thirty min later, serine/threonine protein kinase (Akt) and extracellular signal-regulated kinase (ERK) 1/2 activation were detected using western blot method. 48 h later, the cell proliferation, cell cycle and apoptosis were detected using methyl thiazolyl tetrazolium (MTT) and flow cytometry. 17beta-estradiol(17beta-E2, 10(-8) mol/L) or the specific estrogen receptor (ER) antagonist, ICI182780I (10(-6) mol/L) was added. After using the two drugs: triptorelin or GnRH-II, the above parameters were detected again.. After treated with different concentrations (10(-11), 10(-9), 10(-7), 10(-5) mol/L) of triptorelin and GnRH-II, the cell growth was slowed, the percentage of G0/G1 phase cells increased, the percentage of G2/M and S phase cells decreased and the apoptosis rate increased in a dose-dependent manner (P < 0.01, P < 0.05). These changes were more obvious in Ishikawa. The apoptosis rate induced by GnRH-II was higher than that by the same concentration of triptorelin in the three cell lines. Triptorelin and GnRH-II inhibited the Akt and ERK1/2 activity in the endometrial carcinoma cells. 17beta-E2 counteracted the effect of triptorelin and GnRH-II on the endometrial carcinoma cells (P < 0.01, P < 0.05).. Triptorelin and GnRH-II can promote apoptosis rate of endometrial carcinoma cells and inhibit cell proliferation in a dose-dependent manner which may be caused by ERK1/2 and Akt activity inhibition, and is related to the status of PTEN and could be offset by 17beta-E2.

Topics: Antineoplastic Agents, Hormonal; Apoptosis; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Dose-Response Relationship, Drug; Endometrial Neoplasms; Estradiol; Extracellular Signal-Regulated MAP Kinases; Female; Gene Expression; Gonadotropin-Releasing Hormone; Humans; Protein Serine-Threonine Kinases; PTEN Phosphohydrolase; Triptorelin Pamoate

The majority of human endometrial, ovarian and breast cancers express receptors for gonadotropin-releasing hormone (GnRH). Their proliferation is time- and dose-dependently reduced by GnRH and its agonistic analogs. GnRH agonists inhibit the mitogenic signal transduction of growth factor receptors via activation of a phosphotyrosine phosphatase, resulting in downregulation of cancer cell proliferation. Induction of apoptosis is not involved. Recently we showed that the GnRH agonist triptorelin induces activation of nuclear factor-kappaB (NFkappaB) and thus reduces the apoptosis induced by the cytotoxic agent doxorubicin in human endometrial and ovarian cancer cells. The triptorelin-induced reduction of doxorubicin-induced apoptosis was blocked by inhibition of NFkappaB translocation into the nucleus. The present study was conducted to investigate whether knock-down of GnRH receptor expression reduces GnRH agonist-induced anti-apoptotic action. We show that knock-down of GnRH receptor expression results in an increase of doxorubicin-induced apoptosis in human endometrial and ovarian cancers and in the human breast cancer cell line MCF-7. These data further demonstrate that GnRH agonists suppress chemotherapeutic drug-induced apoptosis via activation of the GnRH receptor in these cancers. The situation is different with T-47-D breast cancer cells. After knock-down of GnRH receptor expression doxorubicin-induced apoptosis was decreased, indicating that GnRH agonists do not suppress chemotherapeutic drug-induced apoptosis in T-47-D breast cancer cells.

Topics: Antibiotics, Antineoplastic; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Breast Neoplasms; Cell Line, Tumor; Doxorubicin; Drug Antagonism; Endometrial Neoplasms; Female; Gonadotropin-Releasing Hormone; Humans; Ovarian Neoplasms; Receptors, LHRH; Triptorelin Pamoate

The majority of human endometrial and ovarian cancers express receptors for GnRH type I (GnRH-I). Their proliferation is time- and dose-dependently reduced by GnRH-I and its analogs. GnRH-I analogs activate a phosphotyrosine-phosphatase (PTP) and inhibit EGF-induced mitogenic signal transduction. Recently we found that GnRH type II (GnRH-II) and its agonist [D-Lys6]GnRH-II also have antiproliferative effects on these tumor cells which are significantly greater than those of GnRH-I agonists. In a more recent study, we showed that the antiproliferative activity of GnRH-II on human endometrial and ovarian cancer cell lines is not mediated through the GnRH-I receptor. The underlying signal transduction mechanisms of GnRH-II are still unknown. In this study we showed that the mitogenic effects of growth factors in endometrial and ovarian cancer cell lines were counteracted by GnRH-II agonist [D-Lys6]GnRH-II, indicating an interaction with the mitogenic signal transduction. We showed that [D-Lys6]GnRH-II reduces EGF-induced auto-tyrosine-phosphorylation of EGF-receptors via activation of a PTP and that EGF-induced activation of mitogen-activated protein kinase was blocked in cells treated with [D-Lys6]GnRH-II. Furthermore, EGF-induced expression of the immediate early gene c-fos was inhibited by treatment with [D-Lys6]GnRH-II. After knock-out of GnRH-I receptor expression, GnRH-II agonist [D-Lys6]GnRH-II still activated PTP and inhibited the EGF-induced mitogenic signal transduction. These data indicate, that the effects of GnRH-II are not due to a cross-reaction with the GnRH-I receptor. In conclusion these data suggest that the signaling of GnRH-II agonist [D-Lys6]GnRH-II is comparable to that of GnRH-I analogs.

Topics: Endometrial Neoplasms; Epidermal Growth Factor; ErbB Receptors; Female; Humans; MAP Kinase Kinase Kinases; Ovarian Neoplasms; Protein Tyrosine Phosphatases; Proto-Oncogene Proteins c-fos; Receptors, LHRH; RNA, Messenger; Signal Transduction; Triptorelin Pamoate

The majority of human endometrial and ovarian cancer cell lines express receptors for GnRH. Their proliferation is time- and dose-dependently reduced by GnRH-I and its superagonistic analogues. Recently, we have demonstrated that, in human endometrial and ovarian cancer cell lines except for the ovarian cancer cell line EFO-27, the GnRH-I antagonist cetrorelix has antiproliferative effects comparable to those of GnRH-I agonists, indicating that the dichotomy between GnRH-I agonists and antagonists might not apply to the GnRH system in cancer cells. We were also able to show that the proliferation of human endometrial and ovarian cancer cells was dose- and time-dependently reduced by GnRH-II to a greater extent than by GnRH-I agonists.. In this study we have assessed whether or not the antiproliferative effects of the GnRH-I antagonist cetrorelix in endometrial and ovarian cancer cells are mediated through the GnRH-I receptor.. We analysed the antiproliferative effects of the GnRH-I agonist triptorelin, the GnRH-I antagonist cetrorelix and GnRH-II in a panel of endometrial and ovarian cancer cell lines expressing GnRH-I receptors, in the SK-OV-3 ovarian cancer cell line that does not express GnRH-I receptors, and in four GnRH-I receptor positive GnRH-I receptor knockout cell lines.. We found that, after knockout of the GnRH-I receptor, the antiproliferative effects of the GnRH-I agonist triptorelin were abrogated, whereas those of the GnRH-I antagonist cetrorelix and of GnRH-II persisted.. These data suggest that, in endometrial and ovarian cancer cells, the antiproliferative effects of cetrorelix and of GnRH-II are not mediated through the GnRH-I receptor.

Topics: Antineoplastic Agents, Hormonal; Cell Division; Cell Line, Tumor; Endometrial Neoplasms; Female; Gonadotropin-Releasing Hormone; Hormone Antagonists; Humans; Mutagenesis; Ovarian Neoplasms; Receptors, LHRH; Triptorelin Pamoate

Endometrial stromal sarcoma can present management difficulties due to its lack of response to conventional chemotherapy and radiotherapy. Various hormonal therapies have been shown to reduce tumor volume in both primary and recurrent disease.. A woman who underwent myomectomy was discovered to have a low-grade endometrial stromal sarcoma. Treatment with the gonadotropin-releasing hormone (GnRH) analogue triptorelin before surgery had produced reduction in uterine size. The woman developed tumor recurrence six months after definitive surgical treatment. The tumor enlarged rapidly during a 2-month period, with development of a right-sided hydronephrosis. Repeat administration of triptorelin was accompanied by resolution of the hydronephrosis and reduction in tumor volume. Biopsy results confirmed recurrent low-grade endometrial stromal sarcoma with moderate estrogen and progesterone receptor positivity.. Control of progression of a recurrent endometrial stromal sarcoma was achieved with the GnRH analogue triptorelin. This is the first report in the English-language literature during a 30-year period of single-agent GnRH analogue being an effective treatment intervention in this context.

Topics: Adult; Antineoplastic Agents, Hormonal; Biopsy, Needle; Chemotherapy, Adjuvant; Endometrial Neoplasms; Female; Follow-Up Studies; Humans; Hysterectomy; Immunohistochemistry; Intraoperative Care; Neoplasm Staging; Risk Assessment; Sarcoma, Endometrial Stromal; Tomography, X-Ray Computed; Treatment Outcome; Triptorelin Pamoate

The majority of human endometrial (>80%), ovarian (>80%) and breast (>50%) cancers express GnRH receptors. Their spontaneous and epidermal growth-factor-induced proliferation is dose- and time-dependently reduced by treatment with GnRH and its agonists. In this study, we demonstrate that the GnRH agonist triptorelin inhibits estradiol (E2)-induced cancer cell proliferation.. The proliferation of quiescent estrogen receptor alpha (ER alpha)-/ER beta-positive, but not of ER alpha-negative/ER beta-positive endometrial, ovarian and breast cancer cell lines, was significantly stimulated (P<0.001) (ANOVA) after treatment with E2 (10(-8) M). This effect was time- and dose-dependently antagonized by simultaneous treatment with triptorelin. The inhibitory effect was maximal at 10(-5) M concentration of triptorelin (P<0.001). In addition, we could show that, in ER alpha-/ER beta-positive cell lines, E2 induces activation of serum response element (SRE) and expression of the immediate early-response gene c-fos. These effects were blocked by triptorelin (P<0.001). E2-induced activation of estrogen-response element (ERE) was not affected by triptorelin.. The transcriptional activation of SRE by E2 is due to ER alpha activation of the mitogen-activated protein kinase (MAPK) pathway. This pathway is impeded by GnRH, resulting in a reduction of E2-induced SRE activation and, in consequence, a reduction of E2-induced c-fos expression. This causes downregulation of E2-induced cancer cell proliferation.

Topics: Antineoplastic Agents, Hormonal; Breast Neoplasms; Cell Division; Cell Line, Tumor; Dose-Response Relationship, Drug; Endometrial Neoplasms; Estradiol; Estrogen Receptor alpha; Estrogen Receptor beta; Estrogens; Female; Gene Expression; Genes, fos; Genital Neoplasms, Female; Gonadotropin-Releasing Hormone; Humans; Ovarian Neoplasms; Proto-Oncogene Proteins c-fos; Response Elements; Serum Response Element; Triptorelin Pamoate

Several recent reports have demonstrated the expression of luteinizing hormone-releasing hormone receptors by human ovarian and endometrial cancers. Controversy persists on the relevance of this finding, in particular whether these receptors mediate direct antiproliferative effects of luteinizing hormone-releasing hormone analogues. We correlated the expression of luteinizing hormone-releasing hormone receptors by well-characterized ovarian and endometrial cancer cell lines with the ability of luteinizing hormone-releasing hormone analogues to reduce their proliferation and studied the autoregulation of luteinizing hormone-releasing hormone receptor expression by luteinizing hormone-releasing hormone agonist triptorelin and antagonist cetrorelix. The expression of luteinizing hormone-releasing hormone receptors was assessed in a series of specimens from primary ovarian and endometrial cancers.. Luteinizing hormone-releasing hormone receptor expression was assessed by semiquantitative reverse transcriptase-polymerase chain reaction and radioligand binding assay. Antiproliferative effects were ascertained by proliferation assays in the absence or presence of luteinizing hormone-releasing hormone analogues.. Ovarian (4/6 cell lines) and endometrial (5/6 cell lines) cancer cell lines expressed luteinizing hormone-releasing hormone receptors. The proliferation of these luteinizing hormone-releasing hormone receptor-positive cell lines was dose- and time-dependently reduced by agonistic and antagonistic luteinizing hormone-releasing hormone analogues. Luteinizing hormone-releasing hormone receptor density was reduced to 80% of controls (control, 100 %; P <.001) by luteinizing hormone-releasing hormone analogues. Seventy percent of primary ovarian cancers and 83% of primary endometrial cancers expressed luteinizing hormone-releasing hormone receptors.. These findings suggest that luteinizing hormone-releasing hormone receptors that are expressed by human ovarian and endometrial cancer cell lines mediate direct antiproliferative effects of luteinizing hormone-releasing hormone analogues. Because most respective primary cancers expressed luteinizing hormone-releasing hormone receptors, these receptors might be used for novel antiproliferative therapeutic approaches and should be further evaluated.

Topics: Binding Sites; Binding, Competitive; Cell Division; Endometrial Neoplasms; Female; Homeostasis; Humans; Ovarian Neoplasms; Receptors, LHRH; RNA, Messenger; Triptorelin Pamoate; Tumor Cells, Cultured

Recently it was shown that a second GnRH system exists in primates. This study was conducted to investigate whether or not the receptor specific for GnRH type II is expressed in human endometrial and ovarian cancer cells and whether or not GnRH-II has effects on tumor cell proliferation. Expression of GnRH-II receptor mRNA in endometrial and ovarian cancer cell lines was demonstrated using RT-PCR and Southern blot analysis. The proliferation of these cell lines was dose- and time-dependently reduced by native GnRH-II. These effects were significantly more potent than the anitproliferative effects of equimolar doses of GnRH-I agonist Triptorelin (p<0.001). In the GnRH-II receptor positive but GnRH-I receptor negative ovarian cancer cell line SK-OV-3 native GnRH-II but not GnRH-I agonist Triptorelin had antiproliferative effects.

Topics: Cell Division; Endometrial Neoplasms; Female; Gonadotropin-Releasing Hormone; Humans; Ovarian Neoplasms; Receptors, LHRH; Triptorelin Pamoate; Tumor Cells, Cultured

The antiproliferative effect of two GnRH agonists (leuprorelin acetate and triptorelin), alone or combined with tamoxifen (TAM) or medroxyprogesterone acetate (MPA), on human estrogen-sensitive endometrial cancer cells (Ishikawa) was investigated. Although ineffective when tested alone in all the culture conditions used, both analogues counteracted or even suppressed the estrogen-stimulated growth of Ishikawa cells. The antiestrogenic effect of TAM or MPA was not modified by their association with high doses of the GnRH analogues, but low concentrations of triptorelin combined with MPA 10(-7) M determined a reduction in cell numbers which was greater than that obtained with the progestin or the analogue alone. In addition, analogue treatment prevented the estrogen-induced decrease in the level of estrogen receptors. Our data provide evidence that GnRH agonists can directly inhibit estrogen-stimulated endometrial cancer cell growth and suggest that they may interfere with steroid-receptor machinery.

Topics: Antineoplastic Agents, Hormonal; Cell Division; Drug Synergism; Endometrial Neoplasms; Estrogen Receptor Modulators; Estrogens; Female; Gonadotropin-Releasing Hormone; Humans; Immunohistochemistry; Leuprolide; Medroxyprogesterone Acetate; Receptors, Estrogen; Receptors, Progesterone; Tamoxifen; Triptorelin Pamoate; Tumor Cells, Cultured

The expression of luteinizing hormone-releasing hormone (LHRH) and its receptor as a part of an autocrine regulatory system of cell proliferation has been demonstrated in a number of human malignant tumours, including cancers of the endometrium. The signalling pathway through which LHRH acts in endometrial cancer is distinct from that in pituitary gonadotrophs. The LHRH receptor interacts with the mitogenic signal transduction of growth factor receptors via activation of a phosphotyrosine phosphatase, resulting in down-regulation of cancer cell proliferation. In addition, LHRH activates nucleus factor kappaB (NFkappaB) and protects the cancer cells from apoptosis. This study was conducted to investigate additional signalling mechanisms of the LHRH receptor cooperating with NFkappaB in endometrial cancer cells.. The LHRH agonist triptorelin-induced activator protein-1 (AP-1) activation was analysed using a pAP-1-SEAP reporter gene assay. Expression of c-jun mRNA was quantified using quantitative reverse transcription (RT)-PCR. c-Jun N-terminal kinase (JNK) activity was measured by quantification of phosphorylated c-Jun protein.. Treatment of Ishikawa and Hec-1A human endometrial cancer cells with 100 nM triptorelin resulted in a 3.1-fold and 3.5-fold activation of AP-1 respectively (P<0.05). If the cells had been made quiescent, treatment with triptorelin (100 nM) resulted in a 41.7-fold and 48.6-fold increase of AP-1 activation respectively (P<0.001). This effect was completely blocked by simultaneous treatment with pertussis toxin (PTX). A 17.6-fold and 17.3-fold increase of c-jun mRNA expression respectively (P<0.001) was obtained after 20 min of stimulation with triptorelin (100 nM). Treatment with 1 nM triptorelin resulted in a 12.5-fold or an 11.9-fold increase, and treatment with 10 pM triptorelin resulted in a 6.5-fold or a 5.2-fold increase of maximal c-jun mRNA expression respectively (P<0.001). Maximal c-Jun phosphorylation (68.5-fold and 60.2-fold, respectively, P<0.001) was obtained after 90 min incubation with triptorelin (100 nM).. These results suggest that the LHRH agonist triptorelin stimulates the activity of AP-1 in human endometrial cancer cells mediated through PTX-sensitive G-protein alphai. In addition, triptorelin activates JNK, known to activate AP-1. In earlier investigations we have shown that triptorelin does not activate phospholipase and protein kinase C (PKC) in endometrial cancer cells. In addition, it has been demonstrated that triptorelin inhibits growth factor-induced mitogen activated protein kinase (MAPK, ERK) activity. Thus triptorelin-induced activation of the JNK/AP-1 pathway in endometrial cancer cells is independent of the known AP-1 activators, PKC or MAPK (ERK).

Topics: Antineoplastic Agents, Hormonal; Blotting, Western; Endometrial Neoplasms; Female; Gonadotropin-Releasing Hormone; Humans; JNK Mitogen-Activated Protein Kinases; Mitogen-Activated Protein Kinases; NF-kappa B; Pancreatitis-Associated Proteins; Protein Kinase C; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Signal Transduction; Stimulation, Chemical; Transcription Factor AP-1; Triptorelin Pamoate; Tumor Cells, Cultured

Gonadotropin-releasing hormone (GnRH) has been shown to have an inhibitory effect on the growth of several hormone-dependent human tumors. We have treated a human endometrial cancer cell line which expresses GnRH receptor with GnRH analog, D-Trp6-LHRH, in order to study whether there are differences in cell cycle kinetic response. Flow cytometric analysis revealed that cultured carcinoma cells showed a cell cycle arrest at the G1-S transition after treatment with 10 microM D-Trp6-LHRH for 36 h. Western blot analysis showed that the level of p16 protein was obvious following 24 h of D-Trp6-LHRH treatment. These results suggest that the mechanism by which GnRH inhibits the growth of endometrial carcinoma cells may include effects on cell cycle arrest.

Topics: Endometrial Neoplasms; Female; Flow Cytometry; G1 Phase; Gonadotropin-Releasing Hormone; Humans; Triptorelin Pamoate; Tumor Cells, Cultured

Although specific binding sites for LH-releasing hormone (LHRH) and its analogs have been demonstrated in biopsy samples of human endometrial cancer, their biological significance remains obscure. In this study we evaluated whether binding sites for LHRH are also present in the human endometrial cancer cell lines HEC-1A and Ishikawa and if such sites could mediate antiproliferative effects of LHRH analogs. Using [125I,D-Trp6]LHRH as a ligand, a high affinity/low capacity binding site was detected in both lines: HEC-1A line, dissociation constant (Kd)1 = 5.7 x 10(-9) mol/L, binding capacity (Bmax)1 = 78 fmol/10(6) cells; Ishikawa line, Kd1 = 4.2 x 10(-9) mol/L, Bmax1 = 29 fmol/10(6) cells. In addition, a second class of low affinity/high capacity binding sites for LHRH was demonstrated (HEC-1A line, Kd2 = 1.4 x 10(-6) mol/L, Bmax2 = 21 pmol/10(6) cells; Ishikawa, Kd2 = 4 x 10(-6) mol/L, Bmax2 = 32 pmol/10(6) cells). In the presence of 10(-5) mol/L agonist [D-Trp6]LHRH (triptorelin), the proliferation of HEC-1A and Ishikawa cell lines was significantly reduced to 76 +/- 2% and 88 +/- 4% of controls, respectively, after 24 h and to 64 +/- 2% and 62 +/- 2%, respectively, after 6 days. Dose-response experiments showed that lower concentrations (10(-9) mol/L) of the agonist decreased the proliferation to 80 +/- 1% for the HEC-1A line and 71 +/- 2% of controls for the Ishikawa line after 6 days. Antiproliferative effects are enhanced by increasing the doses of triptorelin and were maximal in this series of experiments at 10(-5) mol/L, the proliferation in the HEC-1A line being 62 +/- 1% and in the Ishikawa line 52 +/- 2% of controls, respectively. Similar time- and dose-dependent antiproliferative effects were obtained in both cell lines with the LHRH antagonist SB-75 (cetrorelix). These data suggest that LHRH analogs can directly inhibit the proliferation of human endometrial cancer cells in vitro. This direct action could be mediated through the high affinity LHRH binding sites.

Topics: Amino Acid Sequence; Binding Sites; Cell Division; Dose-Response Relationship, Drug; Drug Stability; Endometrial Neoplasms; Female; Gonadotropin-Releasing Hormone; Humans; Molecular Sequence Data; Triptorelin Pamoate; Tumor Cells, Cultured