Gonadotropin-releasing hormone activates mitogen-activated protein kinase in human ovarian and placental cells

Sung Keun Kang, Chen Jei Tai, Kwai Wa Cheng, Peter C K Leung

Research output: Contribution to journalArticle

48 Citations (Scopus)

Abstract

Considering that the action of gonadotropin-releasing hormone (GnRH) may be mediated via different signaling pathways in extrapituitary tissues, in the present study we investigated the role of the human GnRH receptor (GnRHR) in activating mitogen-activated protein kinases (MAPKs), which regulate cell growth, division, and differentiation. The phosphorylation state of p44 and p42 MAPKs was examined using antibodies that distinguish phospho-p44/42 MAPK (P-MAPK, Thr202/Tyr204) from total p44/42 MAPK (T-MAPK, activated plus inactivated) in human ovarian and placental cells. Cell cultures were treated with various concentrations of a GnRH agonist, (D-Ala6)-GnRH, for 5 min. (D-Ala6)-GnRH stimulated a rapid activation of P-MAPK in human granulosa-luteal cells (hGLCs) and immortalized extravillous trophoblast (IEVT) cells. Interestingly, (D-Ala6)-GnRH treatment of ovarian cancer (OVCAR-3) and placental carcinoma (JEG-3) cells induced a biphasic regulatory pattern in P-MAPK activity. In contrast, no change of T-MAPK levels was observed following addition of the GnRH agonist in the ovarian and placental cells examined. The physiological implication of MAPK activation by GnRH in the ovarian and placental cells was also investigated. Human GLCs were treated with (D-Ala6)-GnRH for 24 h, and progesterone secretion was measured by an established RIA. (D-Ala6)-GnRH induced a significant decrease in progesterone secretion with maximum inhibition (a 45% decrease over basal level) at 10-7 M. This inhibitory effect was completely reversed by pretreatment with MAPK/ERK kinase 1 (MEK1) inhibitor (PD98059), suggesting the involvement of the MAPK pathway in hGLCs. Placental JEG-3 cells were treated with (D-Ala6)-GnRH for 24 h, and βhCG mRNA level was measured using Northern blot analysis. (D-Ala6)-GnRH stimulated the expression of βhCG mRNA to 160% of control value in JEG-3 cells. In contrast to the ovarian cells, pretreatment of JEG-3 cells with PD98059 failed to block the stimulatory effect of GnRH on βhCG mRNA level, suggesting that other signaling pathway(s) may play a more dominant role in GnRH-induced βhCG mRNA expression. To our knowledge, this is the first demonstration that (1) GnRH induces activation of the MAPK signaling pathway in normal and carcinoma cells of the human ovary and placenta, and (2) MAPK mediates the direct action of GnRH on progesterone production in hGLCs.

Original languageEnglish
Pages (from-to)143-151
Number of pages9
JournalMolecular and Cellular Endocrinology
Volume170
Issue number1-2
DOIs
Publication statusPublished - Dec 22 2000
Externally publishedYes

Fingerprint

Mitogen-Activated Protein Kinases
Gonadotropin-Releasing Hormone
Luteal Cells
Progesterone
Messenger RNA
Chemical activation
Mitogen-Activated Protein Kinase 1
MAP Kinase Kinase 1
Carcinoma
Phosphorylation
Trophoblasts
Cell growth
Cell culture
Northern Blotting
Cell Division
Ovarian Neoplasms
Placenta
Cell Differentiation
Ovary
Phosphotransferases

Keywords

  • GnRH
  • GnRH receptor
  • MAPK
  • Ovary
  • Placenta

ASJC Scopus subject areas

  • Endocrinology
  • Endocrinology, Diabetes and Metabolism

Cite this

Gonadotropin-releasing hormone activates mitogen-activated protein kinase in human ovarian and placental cells. / Keun Kang, Sung; Tai, Chen Jei; Wa Cheng, Kwai; Leung, Peter C K.

In: Molecular and Cellular Endocrinology, Vol. 170, No. 1-2, 22.12.2000, p. 143-151.

Research output: Contribution to journalArticle

@article{2ea124f25fdc481ba3045a2024a7a02a,
title = "Gonadotropin-releasing hormone activates mitogen-activated protein kinase in human ovarian and placental cells",
abstract = "Considering that the action of gonadotropin-releasing hormone (GnRH) may be mediated via different signaling pathways in extrapituitary tissues, in the present study we investigated the role of the human GnRH receptor (GnRHR) in activating mitogen-activated protein kinases (MAPKs), which regulate cell growth, division, and differentiation. The phosphorylation state of p44 and p42 MAPKs was examined using antibodies that distinguish phospho-p44/42 MAPK (P-MAPK, Thr202/Tyr204) from total p44/42 MAPK (T-MAPK, activated plus inactivated) in human ovarian and placental cells. Cell cultures were treated with various concentrations of a GnRH agonist, (D-Ala6)-GnRH, for 5 min. (D-Ala6)-GnRH stimulated a rapid activation of P-MAPK in human granulosa-luteal cells (hGLCs) and immortalized extravillous trophoblast (IEVT) cells. Interestingly, (D-Ala6)-GnRH treatment of ovarian cancer (OVCAR-3) and placental carcinoma (JEG-3) cells induced a biphasic regulatory pattern in P-MAPK activity. In contrast, no change of T-MAPK levels was observed following addition of the GnRH agonist in the ovarian and placental cells examined. The physiological implication of MAPK activation by GnRH in the ovarian and placental cells was also investigated. Human GLCs were treated with (D-Ala6)-GnRH for 24 h, and progesterone secretion was measured by an established RIA. (D-Ala6)-GnRH induced a significant decrease in progesterone secretion with maximum inhibition (a 45{\%} decrease over basal level) at 10-7 M. This inhibitory effect was completely reversed by pretreatment with MAPK/ERK kinase 1 (MEK1) inhibitor (PD98059), suggesting the involvement of the MAPK pathway in hGLCs. Placental JEG-3 cells were treated with (D-Ala6)-GnRH for 24 h, and βhCG mRNA level was measured using Northern blot analysis. (D-Ala6)-GnRH stimulated the expression of βhCG mRNA to 160{\%} of control value in JEG-3 cells. In contrast to the ovarian cells, pretreatment of JEG-3 cells with PD98059 failed to block the stimulatory effect of GnRH on βhCG mRNA level, suggesting that other signaling pathway(s) may play a more dominant role in GnRH-induced βhCG mRNA expression. To our knowledge, this is the first demonstration that (1) GnRH induces activation of the MAPK signaling pathway in normal and carcinoma cells of the human ovary and placenta, and (2) MAPK mediates the direct action of GnRH on progesterone production in hGLCs.",
keywords = "GnRH, GnRH receptor, MAPK, Ovary, Placenta",
author = "{Keun Kang}, Sung and Tai, {Chen Jei} and {Wa Cheng}, Kwai and Leung, {Peter C K}",
year = "2000",
month = "12",
day = "22",
doi = "10.1016/S0303-7207(00)00320-8",
language = "English",
volume = "170",
pages = "143--151",
journal = "Molecular and Cellular Endocrinology",
issn = "0303-7207",
publisher = "Elsevier Ireland Ltd",
number = "1-2",

}

TY - JOUR

T1 - Gonadotropin-releasing hormone activates mitogen-activated protein kinase in human ovarian and placental cells

AU - Keun Kang, Sung

AU - Tai, Chen Jei

AU - Wa Cheng, Kwai

AU - Leung, Peter C K

PY - 2000/12/22

Y1 - 2000/12/22

N2 - Considering that the action of gonadotropin-releasing hormone (GnRH) may be mediated via different signaling pathways in extrapituitary tissues, in the present study we investigated the role of the human GnRH receptor (GnRHR) in activating mitogen-activated protein kinases (MAPKs), which regulate cell growth, division, and differentiation. The phosphorylation state of p44 and p42 MAPKs was examined using antibodies that distinguish phospho-p44/42 MAPK (P-MAPK, Thr202/Tyr204) from total p44/42 MAPK (T-MAPK, activated plus inactivated) in human ovarian and placental cells. Cell cultures were treated with various concentrations of a GnRH agonist, (D-Ala6)-GnRH, for 5 min. (D-Ala6)-GnRH stimulated a rapid activation of P-MAPK in human granulosa-luteal cells (hGLCs) and immortalized extravillous trophoblast (IEVT) cells. Interestingly, (D-Ala6)-GnRH treatment of ovarian cancer (OVCAR-3) and placental carcinoma (JEG-3) cells induced a biphasic regulatory pattern in P-MAPK activity. In contrast, no change of T-MAPK levels was observed following addition of the GnRH agonist in the ovarian and placental cells examined. The physiological implication of MAPK activation by GnRH in the ovarian and placental cells was also investigated. Human GLCs were treated with (D-Ala6)-GnRH for 24 h, and progesterone secretion was measured by an established RIA. (D-Ala6)-GnRH induced a significant decrease in progesterone secretion with maximum inhibition (a 45% decrease over basal level) at 10-7 M. This inhibitory effect was completely reversed by pretreatment with MAPK/ERK kinase 1 (MEK1) inhibitor (PD98059), suggesting the involvement of the MAPK pathway in hGLCs. Placental JEG-3 cells were treated with (D-Ala6)-GnRH for 24 h, and βhCG mRNA level was measured using Northern blot analysis. (D-Ala6)-GnRH stimulated the expression of βhCG mRNA to 160% of control value in JEG-3 cells. In contrast to the ovarian cells, pretreatment of JEG-3 cells with PD98059 failed to block the stimulatory effect of GnRH on βhCG mRNA level, suggesting that other signaling pathway(s) may play a more dominant role in GnRH-induced βhCG mRNA expression. To our knowledge, this is the first demonstration that (1) GnRH induces activation of the MAPK signaling pathway in normal and carcinoma cells of the human ovary and placenta, and (2) MAPK mediates the direct action of GnRH on progesterone production in hGLCs.

AB - Considering that the action of gonadotropin-releasing hormone (GnRH) may be mediated via different signaling pathways in extrapituitary tissues, in the present study we investigated the role of the human GnRH receptor (GnRHR) in activating mitogen-activated protein kinases (MAPKs), which regulate cell growth, division, and differentiation. The phosphorylation state of p44 and p42 MAPKs was examined using antibodies that distinguish phospho-p44/42 MAPK (P-MAPK, Thr202/Tyr204) from total p44/42 MAPK (T-MAPK, activated plus inactivated) in human ovarian and placental cells. Cell cultures were treated with various concentrations of a GnRH agonist, (D-Ala6)-GnRH, for 5 min. (D-Ala6)-GnRH stimulated a rapid activation of P-MAPK in human granulosa-luteal cells (hGLCs) and immortalized extravillous trophoblast (IEVT) cells. Interestingly, (D-Ala6)-GnRH treatment of ovarian cancer (OVCAR-3) and placental carcinoma (JEG-3) cells induced a biphasic regulatory pattern in P-MAPK activity. In contrast, no change of T-MAPK levels was observed following addition of the GnRH agonist in the ovarian and placental cells examined. The physiological implication of MAPK activation by GnRH in the ovarian and placental cells was also investigated. Human GLCs were treated with (D-Ala6)-GnRH for 24 h, and progesterone secretion was measured by an established RIA. (D-Ala6)-GnRH induced a significant decrease in progesterone secretion with maximum inhibition (a 45% decrease over basal level) at 10-7 M. This inhibitory effect was completely reversed by pretreatment with MAPK/ERK kinase 1 (MEK1) inhibitor (PD98059), suggesting the involvement of the MAPK pathway in hGLCs. Placental JEG-3 cells were treated with (D-Ala6)-GnRH for 24 h, and βhCG mRNA level was measured using Northern blot analysis. (D-Ala6)-GnRH stimulated the expression of βhCG mRNA to 160% of control value in JEG-3 cells. In contrast to the ovarian cells, pretreatment of JEG-3 cells with PD98059 failed to block the stimulatory effect of GnRH on βhCG mRNA level, suggesting that other signaling pathway(s) may play a more dominant role in GnRH-induced βhCG mRNA expression. To our knowledge, this is the first demonstration that (1) GnRH induces activation of the MAPK signaling pathway in normal and carcinoma cells of the human ovary and placenta, and (2) MAPK mediates the direct action of GnRH on progesterone production in hGLCs.

KW - GnRH

KW - GnRH receptor

KW - MAPK

KW - Ovary

KW - Placenta

UR - http://www.scopus.com/inward/record.url?scp=0034704389&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0034704389&partnerID=8YFLogxK

U2 - 10.1016/S0303-7207(00)00320-8

DO - 10.1016/S0303-7207(00)00320-8

M3 - Article

C2 - 11162898

AN - SCOPUS:0034704389

VL - 170

SP - 143

EP - 151

JO - Molecular and Cellular Endocrinology

JF - Molecular and Cellular Endocrinology

SN - 0303-7207

IS - 1-2

ER -