Hepatocyte growth factor promotes cell proliferation and inhibits progesterone secretion via PKA and MAPK pathways in a human granulosa cell line

Abstract

Hepatocyte growth factor (HGF) is a mesenchymal-derived paracrine factor that acts through a c-met receptor. The activated c-met receptor recruits various signal proteins. We used a steroidogenic human granulosa-like tumor cell line (KGN cells) to analyze the biological function of HGF in human ovary cells. First, we designed a method to analyze local production and action of HGF in the human ovary. Although c-met mRNA is expressed in KGN cells, granulosa lutein, theca, and ovarian stroma cells, we observed HGF mRNA only in theca and stroma cells. Adding HGF to the medium enhanced mitogenic activity in KGN cells. We next examined the activation of intracellular signal transduction molecules induced by HGF in KGN cells. Here, we showed that HGF activated the distinct phosphorylation of Raf-1, MEK1/2, and ERK1/2, but did not induce phosphorylation of Akt. HGF enhanced the phosphorylation of Elk-1 and c-Jun as nuclear transcription factors. U0126, a MEK1/2 inhibitor, completely abrogated the phosphorylation of ERK1/2 and the cell proliferation in response to HGF. In contrast, H-89, a protein kinase A inhibitor, further enhanced the HGF-induced phosphorylation of ERK1/2 and cell proliferation. In addition, we revealed that HGF suppressed progesterone synthesis in KGN cells. Adding HGF suppressed the forskolin-induced steroidogenic acute regulatory protein (StAR) expression, which is a key regulator in progesterone synthesis. Crosstalk signals between PKA and the mitogen-activated protein kinase (MAPK) pathway were mutually inhibitory. These results demonstrated for the first time that theca cell-derived HGF may be capable of stimulating the proliferation of granulosa cells and suppressing progesterone synthesis via an activating MAPK pathway.

Phenotypic, Transcriptional, and Functional Analysis of Liver Mesenchymal Stromal Cells and Their Immunomodulatory Properties

“…Our data confirm findings by de Mare‐Bredemeijer et al, which showed a higher expression of PTGS1 in L‐MSCs than in BM‐MSCs . Third, HGF, which is known to have antiapoptotic and anti–T cell proliferative properties, was expressed exclusively in L‐MSCs, similar to findings reported previously . HGF transcripts were found in MSCs previously and thought to be responsible for their ability to avoid allorecognition .…”

Participation of Mitogen-Activated Protein Kinase in Luteinizing Hormone-Induced Differential Regulation of Steroidogenesis and Steroidogenic Gene Expression in Mural and Cumulus Granulosa Cells of Mouse Preovulatory Follicles1

“…The MAPK3/1-dependent pathway also has been reported as being involved in the regulation of steroidogenesis in granulosa cells; however, its precise role in this process is controversial. Some studies suggest that activation of MAPK is required for promoting steroidogenesis and steroidogenic gene expression in granulosa cells [36][37][38][39][40][41][42], whereas other studies indicate that activation of MAPK3/1 suppresses granulosa cell steroidogenesis and steroidogenic gene expression [38,[43][44][45]. Notably, most of the previous studies use either human luteinizing granulosa cells derived from patients receiving in vitro fertilization treatment or rat granulosa cells isolated from early antral follicles.…”

Chronic exposure to fulvestrant promotes overexpression of the c-Met receptor in breast cancer cells: implications for tumour–stroma interactions

“…4C). Interestingly, although c-Met activation has been demonstrated to promote proliferation in certain cell types (Wang et al 2003, Taniguchi et al 2004, HGF/SF did not produce any significant change in the growth of either cell type over a period of 7 days (Fig. 4D).…”