Cyclophosphamide promotes the proliferation inhibition of mouse ovarian granulosa cells and premature ovarian failure by activating the lncRNA-Meg3-p53-p66Shc pathway

The dysfunction of ovarian granulosa cells (OGCs) directly affects the premature ovarian failure (POF). In vivo experiments showed that cyclophosphamide significantly induced mouse ovarian atrophy and proliferation inhibition of OGCs. The expressions of p53, p66Shc and p16 were significantly higher in OGCs of the cyclophosphamide treatment group. MTT assay showed that cyclophosphamide effectively inhibited the proliferation of OGCs in vitro. SA-β-Gal staining showed that the OGCs in the cyclophosphamide treatment group had many senescent cells. And, the expression of p53, p66Shc, p16 and cleaved caspase-3 in the OGCs of the cyclophosphamide treatment group significant increases. The Northern blot showed that the intensity of the lncRNA-Meg3 hybridization signal of the OGCs in the cyclophosphamide treatment group was significantly higher than that in the control group. ChIP results confirmed the significant increase in the obtained p66Shc promoter DNA fragment, which was enriched on p53 protein, in the OGCs treated with cyclophosphamide. When cyclophosphamide treatment was conducted after siRNA-Meg3 was used, the expression of endogenous lncRNA-Meg3, p53, p66Shc, p16 and cleaved caspase-3 was significantly lower than that in the siRNA-Mock control group. In summary, cyclophosphamide promotes the proliferation inhibition of mouse OGCs and premature ovarian failure by activating the lncRNA-Meg3-p53-p66Shc pathway.