Proliferation of TSU-Pr1, a human prostatic carcinoma cell line is stimulated by gonadotropin-releasing hormone (original) (raw)
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GnRH as a Cell Proliferation Regulator: Mechanism of Action and Evolutionary Implications
Zoological Science, 2004
Gonadotropin-releasing hormone (GnRH) is well known as the central regulator of the reproductive system through its stimulation of gonadotropin release from the pituitary. Studies on GnRH have demonstrated that GnRH has both stimulatory and inhibitory effects on cell proliferation depending on the cell type; however, the mechanisms of these effects remain to be elucidated. Against this background we used four human cell lines, TSU-Pr1, Jurkat, HHUA and DU145, and newly found that GnRH increased or decreased the colony-formation depending on the cell line. Moreover, we demonstrated that the stimulatory and inhibitory effects of GnRH exhibit distinct ligand selectivities. In order to investigate the molecular basis of these phenomena, analyses of the expression of human GnRH receptors were performed and, moreover, the effects of GnRH were analyzed under conditions in which human GnRH receptors were knocked down by the technique of RNA interference. Consequently, it was found that human type II GnRH receptor, which had been suspected of being nonfunctional because of alterations in its sequence, is involved in the effects of GnRH on cell proliferation. In this article, the influence of the autocrine activities of the cells is also reviewed, focusing on the characteristics of substances secreted from the four cell lines. Based on recent studies of GnRH and its receptors and our up-to-date findings, the evolutionary implications of GnRH action are discussed.
Endocrinology, 2003
tumor growth that may, in part, be mediated by direct activation of GnRH receptors (GnRHRs) expressed on tumor cells. However, it is not fully understood how the GnRHR mediates these growth effects. This study aimed to determine how the presence or absence of this receptor in different cell types might affect the ability of GnRH to directly mediate growth effects. We demonstrate that continuous treatment with GnRH or a GnRH agonist (GnRHA) induces an anti-proliferative effect in a gonadotrope-derived cell line (LβT2) and also in HEK293 cells stably expressing either the rat or human GnRHR. The anti-proliferative effect was time-and dose-dependent and was verified using [ 3 H]-thymidine incorporation, light microscopy and analysis of cell number. Inhibition was specifically mediated via the GnRHR as cotreatment of the GnRHR-expressing cell lines with a GnRH antagonist blocked the growth suppressive effect induced by GnRHA treatment. Cell cycle analysis revealed that the GnRHA treated HEK/GnRHR cell lines induced an accumulation of cells in the G2/M phase while a G0/G1 arrest was observed in LβT2 cells. GnRHA treatment also caused a small but significant increase in apoptotic cells. This study provides evidence for a direct role for the GnRHR in mediating anti-proliferative events in two cell systems neither of which were derived from extra-pituitary reproductive tumors. The ability to induce these effects, irrespective of the cell system involved, has implications regarding the use of GnRH analogs for the treatment of endocrine-related disorders and tumors. K, Plonowski A, Varga JL, Halmos G. 2001 Hypothalamic hormones and cancer. Front Neuroendocrinol 22:248-91 3. Schally AV 1999 Luteinizing hormone-releasing hormone analogs: their impact on the control of tumorigenesis. Peptides 20:1247-62 4. Eidne KA, Flanagan CA, Millar RP 1985 Gonadotropin-releasing hormone binding sites in human breast carcinoma. Science 229:989-91 5. Eidne KA, Flanagan CA, Harris NS, Millar RP 1987 Gonadotropinreleasing hormone (GnRH)-binding sites in human breast cancer cell lines and inhibitory effects of GnRH antagonists. J Clin Endocrinol Metab 64:425-32 6. Miller WR, Scott WN, Morris R, Fraser HM, Sharpe RM 1985 Growth of human breast cancer cells inhibited by a luteinizing hormonereleasing hormone agonist. Nature 313:231-3 7. Limonta P, Dondi D, Moretti RM, Maggi R, Motta M 1992 Antiproliferative effects of luteinizing hormone-releasing hormone agonists on the human prostatic cancer cell line LNCaP. J Clin Endocrinol Metab 75:207-12 8. Dondi D, Limonta P, Moretti RM, Marelli MM, Garattini E, Motta M 1994 Antiproliferative effects of luteinizing hormone-releasing hormone (LHRH) agonists on human androgen-independent prostate cancer cell line DU 145: evidence for an autocrine-inhibitory LHRH loop. Cancer
Endocrinology, 2003
hibition of tumor growth that may be mediated in part by direct activation of GnRH receptors (GnRHRs) expressed on tumor cells. However, it is not fully understood how the GnRHR mediates these growth effects. This study aimed to determine how the presence or absence of this receptor in different cell types might affect the ability of GnRH to directly mediate growth effects. We demonstrate that continuous treatment with GnRH or a GnRH agonist (GnRHA) induces an antiproliferative effect in a gonadotrope-derived cell line (LT2) and also in HEK293 cells stably expressing either the rat or human GnRHR. The antiproliferative effect was time and dose dependent and was verified using [ 3 H]thymidine incorporation, light microscopy, and analysis of cell number. Inhibition was specifically mediated via the GnRHR, as co-treatment of the GnRHR-expressing cell lines with a GnRH antagonist blocked the growth-suppressive effect induced by GnRHA treatment. Cell cycle analysis revealed that GnRHA-treated HEK/GnRHR cell lines induced an accumulation of cells in the G 2 /M phase, whereas a G 0 /G 1 arrest was observed in LT2 cells. GnRHA treatment also caused a small, but significant, increase in apoptotic cells. This study provides evidence for a direct role for the GnRHR in mediating antiproliferative events in two cell systems, neither of which was derived from extrapituitary reproductive tumors. The ability to induce these effects, regardless of the cell system involved, has implications regarding the use of GnRH analogs for the treatment of endocrine-related disorders and tumors.
Molecular Medicine Reports, 2015
Gonadotropin-releasing hormone (GnRH), or its analogues have been demonstrated to exhibit anti-proliferative effects on tumour cells in ovarian, endometrial and breast cancer through GnRH-receptors (GnRH-R). However, the role of GnRH in nasopharyngeal carcinoma (NPC) remains to be elucidated. In order to investigate the effects of GnRH in NPC, the present study examined the expression of the GnRH-R transcript in NPC and investigated the phenotypic changes in HK1 cells, a recurrent NPC-derived cell line, upon receiving GnRH treatment. Firstly, the GnRH-R transcript was demonstrated in the NPC cell lines and four snap frozen biopsies using reverse transcription-quantitative polymerase chain reaction. In addition, immunohistochemistry revealed the expression of GnRH-R in two of the eight (25%) NPC specimens. Treatment with GnRH induced a rapid increase in intracellular ionised calcium concentration in the NPC cells. GnRH and its agonists, triptorelin and leuprolide, exerted anti-proliferative effects on the NPC cells, as determined using an MTS assay. GnRH did not induce any cell cycle arrest in the HK1 cells under the conditions assessed in the present study. Time-lapse imaging demonstrated a reduction in cell motility in the GnRH-treated cells. In conclusion, GnRH, or its analogues may have antitumour effects on NPC cells. The consequences of alterations in the levels of GnRH on the progression of NPC require further examination.
Endocrinology, 2004
hibition of tumor growth that may be mediated in part by direct activation of GnRH receptors (GnRHRs) expressed on tumor cells. However, it is not fully understood how the GnRHR mediates these growth effects. This study aimed to determine how the presence or absence of this receptor in different cell types might affect the ability of GnRH to directly mediate growth effects. We demonstrate that continuous treatment with GnRH or a GnRH agonist (GnRHA) induces an antiproliferative effect in a gonadotrope-derived cell line (LT2) and also in HEK293 cells stably expressing either the rat or human GnRHR. The antiproliferative effect was time and dose dependent and was verified using [ 3 H]thymidine incorporation, light microscopy, and analysis of cell number. Inhibition was specifically mediated via the GnRHR, as co-treatment of the GnRHR-expressing cell lines with a GnRH antagonist blocked the growth-suppressive effect induced by GnRHA treatment. Cell cycle analysis revealed that GnRHA-treated HEK/GnRHR cell lines induced an accumulation of cells in the G 2 /M phase, whereas a G 0 /G 1 arrest was observed in LT2 cells. GnRHA treatment also caused a small, but significant, increase in apoptotic cells. This study provides evidence for a direct role for the GnRHR in mediating antiproliferative events in two cell systems, neither of which was derived from extrapituitary reproductive tumors. The ability to induce these effects, regardless of the cell system involved, has implications regarding the use of GnRH analogs for the treatment of endocrine-related disorders and tumors.
Cancer Immunology, Immunotherapy, 2010
As the continuation of a previous study, synthetic peptides corresponding to the extracellular domains of human gonadotropin-releasing hormone (GnRH) receptor were used to generate additional monoclonal antibodies which were further characterized biochemically and immunologically. Among those identiWed to recognize GnRH receptor, monoclonal antibodies designated as GHR-103, GHR-106 and GHR-114 were found to exhibit high aYnity (Kd · 1 £ 10 ¡8 M) and speciWcity to GnRH receptor as judged by the whole cell binding immunoassay and Western blot assay. Both anti-GnRH receptor monoclonal antibodies and GnRH were shown to compete for the same binding site of GnRH receptor on the surface of cultured cancer cells. Growth inhibitions of cancer cells cultured in vitro were demonstrated by cellular apoptosis experiments (TUNEL and MTT assays) under diVerent conditions of treatment with GHR-106 monoclonal antibody or GnRH analogs. It was generally observed that both GnRH I and GHR-106 eVectively induce the apoptosis of cultured cancer cells as determined by TUNEL and MTT assays. Consistently, suppressions of gene expressions at mRNA levels were demonstrated with several ribosomal proteins (P0, P1, P2 and L37), when cancer cells were incubated with GnRH or GHR-106. The widespread expressions of GnRH receptor in almost all of the studied human cancer cell lines were also demonstrated by RT-PCR and Western blot assay, as well as indirect immunoXuorescence assay with either of these monoclonal antibodies as the primary antibody. In view of the longer half life of antibodies as compared to that of GnRH or its analogs, anti-GnRH receptor monoclonal antibodies in humanized forms could function as GnRH analogs and serve as an ideal candidate of anti-cancer drugs for therapeutic treatments of various cancers in humans as well as for fertility regulations.
Regulation of the cell proliferation and migration as extra-pituitary functions of GnRH
General and Comparative Endocrinology, 2013
GnRH was originally identified as a hypothalamic factor which promotes gonadotropin release from the pituitary and was named gonadotropin-releasing hormone (GnRH). However, broad tissue distributions of GnRH and the GnRH receptor in various extrapituitary tissues and organs have been revealed and it has been suggested that GnRH has extrapituitary effects such as neuromodulation, immunomodulation, and regulation of follicular atresia and ovulation. Although a number of studies have been performed on these effects, little is known about the molecular mechanisms and physiological settings in which GnRH exerts its activities in extrapituitary organs or tissues. Our recent studies had demonstrated that GnRH is able to regulate both cell proliferation and cell migration at much lower concentration than that in the peripheral circulation by using human carcinoma cell lines. Moreover, stimulating activity of GnRH on the developing chick embryonic GnRH neurons was also demonstrated and strongly suggests possible involvement of GnRH in some of extrapituitary functions. This mini-review intends to provide solid evidence of GnRH activity in the regulation of cell proliferation and migration and its physiological relevance in extra-pituitary functions. Recent other research, including that in various invertebrates, provides new insight into the evolutionary scenarios of GnRH signaling systems, and GnRH functions. Both proliferating and migrating activities are important fundamental cellular activities and could provide an important clue into understanding what the driving force behind the evolution of the GnRH signaling system was.
2004
Expression of GnRH receptor type-I (GnRHR) and GnRH-I are not restricted to the hypothalamic area, and have been demonstrated in the immune system. GnRH expression in human B lymphocytes has not yet been explored. We therefore investigated GnRH-I expression in human peripheral mononuclear blood cells (PMBC) and B lymphoblastoid cells (B-LCLs). We also investigated the regulation of B-LCL proliferation by GnRH in the presence and absence of interleukin-2 (IL-2). In the present study, we report the preliminary results from our ongoing collaborative study. Materials and Method: RT-PCR was used for expression of locally produced GnRH-I. The effects of GnRH-I on B-LCL proliferation were investigated using a nonradioactive cell proliferation assay. Results: GnRH-I was present in PMBC and in B lymphocyte groups (normal and GnRHR defective B-LCLs). Treatment of normal B-LCLs with GnRH and with Interleukin-2 (IL-2) resulted in a significant increase in proliferation compared with the untreated control (p<0.05). Normal B-LCLs co-treated with IL-2 and GnRH demonstrated higher proliferative responses than IL-2 treatment alone. In GnRHR defective B-LCLs, there were no significant proliferative responses to either GnRH or IL-2 treatment, nor to IL-2 and GnRH cotreatment when compared to controls. Conclusion: We therefore confirm the presence of GnRH transcript in PMBC and B-LCLs. GnRH induced a proliferative response in B-LCLs, an effect mediated by a functional GnRHR. Furthermore, the IL-2 mediated proliferative response in B lymphocytes is modulated by GnRH. Further experimental data are necessary to understand the physiological effects of local GnRH in the immune system.
Fertility and Sterility, 2004
Gonadotropin-releasing hormone (GnRH) agonist exert ''in vivo'' an inhibitory action on the growth of hormone-dependent canine mammary tumours (Lombardi et al. [1999] J. Vet. Pharmacol Ther. 22(1):56-61). The present experiments have been performed ''in vitro'' in order to investigate the mechanisms involved in this direct antiproliferative action of GnRH agonists. In particular, the aim was to study whether these compounds might exert their antiproliferative effect by interfering with the stimulatory action of epidermal growth factor (EGF). To this purpose, the effects of GnRH agonist, Goserelin (GnRH-A), on the mitogenic action of EGF, on EGF-activated intracellular signaling mechanisms (intracellular calcium and nitric oxide production) as well as on ATP induced cell proliferation and signalling, and on the binding of EGF receptors have been evaluated in primary culture of canine mammary tumour cells. The results of these ''in vitro'' studies show that GnRH-A counteracts the mitogenic action of EGF and ATP, decreases the EGF/ATP-induced calcium signalling and reduces EGF binding, probably by means of NO-induced [Ca 2þ ] i downregulation. These data suggest that GnRH agonists may inhibit the proliferation of the tumour cells by interfering with the stimulatory action of EGF.