Elevated SREBP1 accelerates the initiation and growth of pancreatic cancer by targeting SOX9.

Pancreatic cancer is a lethal disease with an insidious onset, and little is known about its early molecular events. Here, we found that the sterol regulatory element-binding protein 1 (SREBP1) expression is gradually upregulated during the initiation of pancreatic cancer. Through in vitro 3D culture of pancreatic acinar cells and experiments in LSL-Kras^G12D/+;Pdx1-Cre (KC) mice, we found that pharmacological inhibition of SREBP1 suppressed pancreatic tumorigenesis. In vitro, either knockdown or pharmacological inhibition of SREBP1 suppressed tumor proliferation but SREBP1 overexpression promoted tumor proliferation. In LSL-Kras^G12D/+;Trp53^fl/+;Pdx1-Cre (KPC) mice, we confirmed the tumor-promoting role of SREBP1 in pancreatic cancer progression. Mechanistically, we revealed SOX9 as a downstream target of SREPB1. SREBP1 inhibition decreased SOX9 expression in both acinar cells and pancreatic cancer cells. Indeed, we identified SREBP1 binding sites in the SOX9 promoter region and reported that SOX9 is transcriptionally regulated by SREBP1. Taken together, our findings demonstrate that SREBP1/SOX9 inhibition suppresses pancreatic cancer initiation and growth, suggesting that SREBP1 could serve as a potential target for cancer screening and treatment.