The E3 Ubiquitin Ligase Asb2α in T Helper 2 Cells Negatively Regulates Antitumor Immunity in Colorectal Cancer

Abstract

The escape of cancer cells from host immunosurveillance involves a shift in immune responses, including an imbalance in Th1 and Th2 cells. A Th1-dominated immune response predicts positive outcomes in colorectal cancer. The E3 ubiquitin ligase, Asb2α, is expressed in Th2 cells, but its roles in T-cell maturation and cancer are unclear. We provide evidence that the Th2 master regulator, Gata3, induces Asb2. Loss of Asb2 did not affect Th differentiation ex vivo, but reduced IL4 production from Th2 cells. We found that high ASB2 expression was associated with poor outcome in colorectal cancer. Loss of Asb2 from hematopoietic cells promoted a Th1 response and attenuated colitis-associated tumorigenesis in mice. Diminished Th2 function correlated with increased IFNγ production and an enhanced type 1 antitumor immune response in Asb2-deficient mice. Our work suggests that Asb2α promotes a Th2 phenotype in vivo, which in turn is associated with tumor progression in a mouse model of colitis.