FRBI Down-regulates K-Ras and c-Myc Genes of Ovarian Cancers and IP3 Signal Pathway

Purpose To investigate the effects of follicle stimulating hormone receptor binding inhibitor (FRBI) on K-Ras, c-Myc and FSHR mRNA and protein levels in sheep oocytes, and further clarify whether FRBI works through the IP3 signaling pathway.

Methods Oocytes were cultured for 24 h in an in vitro maturation medium at 10 IU/mL of FSH and different mass concentrations of FRBI (0, 10, 20, 30 and 40 μg/mL). The contents of K-Ras, c-Myc, cAMP, FSH and IP3 in IVM culture medium were determined by ELISA. The qRT-PCR and Western-blot were used to detect the levels of FSHR mRNA and protein in oocytes.

Results At 24 h, along with the increase of FRBI dose, the mass concentration of c-Myc in COM-1 group to COM-3 group gradually decreased, COM-3 was significantly lower than that in FSH group (P<0.05), and the K-Ras mass concentration in COM-4 group was 24 h and significantly lower than the negative control group (CG) and FSH group (P<0.05); in the COM group,FSHR mRNA and protein expression levels decreased with increasing FRBI dose, high dose group (COM-4) mRNA and protein expression levels significantly lower than the FSH group (P<0.05). The contents of cAMP and IP3 decreased with increasing dose of FRBI, and IP3 in COM-4 group was significantly lower than CG group (P<0.05).

Conclusions In the presence of FSH, FRBI could reduce the production of K-Ras and c-Myc, inhibit the FSHR level of oocytes. FRBI exerts its functions probably through the IP3 signaling pathway.