Coupling to the Histone Acetyltransferase p300 is required by GLI1 to control SDF-1 expression in pancreatic cancer associated fibroblast

VERA RE; LAMBERTI MJ; ALMADA L; RUMIE VITTAR NB; FERNANDEZ ZAPICO ME

Congreso; Midwest Tumor Microenvironment Meeting; 2022

Although the biological role of SDF-1 is established in the tumor microenvironment, the molecular mechanisms controlling its expression/activity are not completely understood. Here we provide evidence of a novel regulatory mechanism controlling the levels of this chemokine in Cancer Associated Fibroblasts (CAFs), a cell type playing major role in tumor development and progression by regulating paracrine signaling in the tumor microenvironment. We demonstrated that the transcription factor GLI1 cooperates with p300 histone acetyltransferase to regulate the expression of SDF-1 in pancreatic cancer CAFs. Using a combination of luciferase assay, ChIP-PCR and qPCR we demonstrate that GLI1 is able to bind to SDF-1 promoter and regulates the expression of this cytokine. We showed that GLI1 inactivation decreased the levels of the histone marks H4ac, H3K27ac, and H3K4ac as well as lower the recruitment of p300. Coimmunoprecipitation assay along with proximity ligation assay (PLA) confirmed the interaction between GLI1 and p300 and that this interaction is through GLI1’s transcriptional activation domain. Additionally, co-transfection of GLI1 and p300 in CAFs lead to synergistic effect on the expression and promoter activity of SDF-1. Finally, using conditioned media from GLI1 overexpressing CAFs we show an induction of migration in pancreatic tumor cells compared to the control transfected cells. Together, these results define the complex GLI1-p300 as a novel regulator of SDF-1 in pancreatic tumor microenvironment and contribute to define pathways playing key roles in tumor development.