The cellular and molecular mechanisms of FGF9 induced steroidogenesis, testis development and tumorigenesis.

• Main Authors: Meng-ShaoLai, 賴孟劭
• Other Authors: Bu-Miin Huang
• Format: Others
• Language: en_US
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/vmzv8k

博士 === 國立成功大學 === 基礎醫學研究所 === 104 === Fibroblast growth factors can modulate the signal of cell proliferation, migration, differentiation and survival to regulate the tissue development and repair. In previous studies, the deficient of FGF9 caused male-to-female sex reversal in XY mouse embryo and FGF9 could promote steroidogenesis in primary Leydig cell. These evidences indicate the crucial role of FGF9 in male individual. However, over-expression of FGF9 was demonstrated to participate in different cancers, such as lung, gastric, prostate and colon cancer. According to these observations, it is important to investigate the detail role of FGF9 in male. In the present study, FGF9 could promote steroidogenesis and activate Akt, JNK, p38 and ERK signals in mouse Leydig cells at the same time. We further investigated the expressional profiles of FGF9 and FGF receptors in testes during development to verify the role of FGF9 in male gonad. FGF9 and FGFRs continuously expressed in the mouse testis from birth to adult. At 17-18 days post coitum (dpc) and postnatal day (pnd) 35-65, FGF9 was highly expressed in the interstitial region. Compared with the evenly and widely expressional patterns of FGFR1 and FGFR4, FGFR2 expression increased in seminiferous tubules at 16-18 dpc and FGFR3 expression increased in interstitial region at 17-18 dpc. In postnatal stage, FGFR2 extensively expressed with higher expression at spermatids and Leydig cells on 35-65 pnd and FGFR3 widely expressed in the whole testis. FGF9 is correlated with the temporal expression profiles of FGFR2 and FGFR3 and possibly associated with testis development. In gonad development, proliferation and differentiation of progenitor cells are important for spermatogenesis and steroidogenesis. However, over-expression of FGF9 participated in cancer initiation and progression. It is important to clarify the function of FGF9 in normal and tumor cells. In the present study, we observed that FGF9 could promote cell proliferation in progenitor (TM3) and tumor (MA-10) Leydig cell lines. Regarding the mechanism investigations, FGF9 activated Akt, ERK, JNK, p38 and PLCγ-1 pathways in TM3 cells and ERK pathway in MA-10 cells, respectively. Regarding cell cycle study, FGF9 increased cyclin D1, cyclin A, cyclin dependent kinase (CDK) 1 and CDK2 protein expressions in TM3 and MA-10 cells. In addition, FGF9 promoted the phosphorylation of retinoblastoma protein (Rb) in both cells. We also demonstrated that FGF9 stimulated FGFR1-4 expression in MA-10 cells and FGFR1, 2 and 4 in TM3 cells, respectively. In addition, p38, JNK or ERK inhibitors could promote Akt phosphorylation but reduce ERK phosphorylation with FGF9 treatment in MA-10 cells, and p38, JNK or ERK inhibitors also increased Akt phosphorylation with FGF9 treatment in TM3 cells. In summary, FGF9 activated Akt, JNK, p38 and ERK to promote steroidogenesis and in Leydig cells, and had expressional correlation with FGFR2 and FGFR3 during testes development. Furthermore, FGF9 activated Akt, ERK, JNK, p38 and PLCγ-1 signals in TM3 Leydig progenitor cells and ERK signal in MA-10 Leydig tumor cells to induce cell proliferation, respectively. FGF9 also promoted cell cycle progression with cyclin/CDK up-regulation in Leydig progenitor and tumor cells. By using serve combined immunodeficiency (SCID) mice, FGF9 significantly promoted MA-10 cell proliferation in vivo. In conclusion, FGF9 plays essential role in steroidogenesis and development in male gonads. However, abnormal expression of FGF9 could cause tumor Leydig cell proliferation inducing tumorigenesis.