ABSTRACT
The mammalian target of rapamycin (mTOR)-sterol regulatory element-binding proteins (SREBPs) signaling promotes lipogenesis. However, mTOR inhibitors also displayed a significant side effect of hyperlipidemia. Thus, it is essential to develop mTOR-specific inhibitors to inhibit lipogenesis. Here, we screened the endogenous inhibitors of mTOR, and identified that FKBP38 as a vital regulator of lipid metabolism. FKBP38 decreased the lipid content
ABSTRACT
Objective:To build the model of the gene FKBP38 (FK506 binding protein 38) conditional knock out in liver.Methods:Transgenic mouse whose FKBP38 gene was flanked with loxP was constructed by embryo microinjection.The FKBP38 gene was deleted by breeding mice harboring two loxP sites in FKBP38 (FKBP38fl/fl) with the mice bearing the expression ofCre recombinase mice driven by an album promoter.Afterward,the genotype of FKBP38 conditional knockout mice was analyzed.Results:①Relative hepatic FKBP38 mRNA levels showed significant difference between FKBP38 conditional knockout mice (FKBP38-/-) and wild type(P＜ 0.001).②Relative hepatic FKBP38 protein expression levels of FKBP38 conditional knockout mice (FKBP38-/-) were significantly different with wild type(P＜0.001).③Relative phosphorylation of hepatic p70 S6K and 4E-BP-1 protein of FKBP38 conditional knockout mice (FKBP38-/-) showed no significant difference,with slight decrease in phosphorylation of 4E-BP-1,compared with wild type.④No significant difference in expression of hepatic Bcl-2 between FKBP38-/-and wild type.Conclusions:The mouse model of the gene FKBP38 (FK506 binding protein 38) conditional knock out in liver is successfully built.
ABSTRACT
Here, we report that B-cell lymphoma 2 (Bcl-2) is a novel target molecule of aspirin in breast cancer cells. Aspirin influenced the formation of a complex by Bcl-2 and FKBP38 and induced the nuclear translocation of Bcl-2 and its phosphorylation. These events inhibited cancer cell proliferation and subsequently enhanced MCF-7 breast cancer cell apoptosis. Bcl-2 knockdown using small interfering RNA (siRNA) delayed apoptotic cell death, which correlated with increased proliferation following aspirin exposure. In contrast, Bcl-2 overexpression enhanced the onset of aspirin-induced apoptosis, which was also associated with a significant increase in Bcl-2 phosphorylation in the nucleus. Therefore, this study may provide novel insight into the molecular mechanism of aspirin, particularly its anticancer effects in Bcl-2- and estrogen receptor-positive breast cancer cells.