HMGA2 Expression in Pancreatic Ductal Adenocarcinoma Controls Tumor Microenvironment and Immunosuppression via IL1α
The basal-like subtype of pancreatic ductal adenocarcinoma (PDAC) is associated with poor outcomes and increased chemoresistance. Expression of high mobility group AT-hook 2 (HMGA2), a chromatin architectural protein, marks basal PDAC cells and associates with specific features of the tumor microenvironment (TME), including more immunosuppressive cancer associated fibroblasts (CAFs) and fewer cytotoxic CD8+ T cells. Expression of HMGA2 by tumor cells leads to upregulation of the immunosuppressive markers interleukin 6 (IL6) and leucine-rich repeat containing protein 15 (LRRC15) in associated fibroblasts. Mechanistically, HMGA2 in the tumor cell binds the interleukin 1 alpha (IL1) promoter and upregulates transcription, increasing IL1 in the TME, in turn inducing immunosuppressive fibroblast polarization, increasing regulatory T cells, and decreasing CD8+ T cells. Blockade of the IL1 signaling axis disrupts this tumor-driven microenvironment phenotype and combines with inhibitors of oncogenic KRAS to improve tumor control.