YY2-CYP51A1 signaling suppresses hepatocellular carcinoma progression by restraining de novo cholesterol biosynthesis.

Lipid accumulation is a frequently observed characteristic of cancer. Lipid accumulation is closely related to tumor progression, metastasis, and drug resistance; however, the mechanism underlying lipid metabolic reprogramming in tumor cells is not fully understood. Yin yang 2 (YY2) is a C2H2‑zinc finger transcription factor that exerts tumor-suppressive effects. However, its involvement in tumor cell lipid metabolic reprogramming remains unclear. In the present study, we identified YY2 as a novel regulator of cholesterol metabolism. We showed that YY2 suppressed cholesterol accumulation in hepatocellular carcinoma (HCC) cells by downregulating the transcriptional activity of cytochrome P450 family 51 subfamily A member 1 (CYP51A1), a key enzyme in de novo cholesterol biosynthesis. Subsequently, through in vitro and in vivo experiments, we demonstrated that this downregulation is crucial for the YY2 tumor suppressive effect. Together, our findings unraveled a previously unprecedented regulation of HCC cells cholesterol metabolism, and eventually, their tumorigenic potential, through YY2 negative regulation on CYP51A1 expression. This study revealed a novel regulatory mechanism of lipid metabolic reprogramming in tumor cells and provided insights into the molecular mechanism underlying the YY2 the suppressive effect. Furthermore, our findings suggest a potential antitumor therapeutic strategy targeting cholesterol metabolic reprogramming using YY2.