GADD45β loss ablates innate immunosuppression in cancer

T cell exclusion from the tumour microenvironment (TME) is a major barrier to overcoming immune escape. Here we identify a myeloid-intrinsic mechanism governed by the NF-κB effector molecule GADD45β that restricts tumour-associated inflammation and T cell trafficking into tumours. In various models of solid cancers refractory to immunotherapies, including hepatocellular carcinoma (HCC) and ovarian adenocarcinoma, Gadd45b inhibition in myeloid cells restored activation of pro-inflammatory tumour-associated macrophages (TAM) and intratumoural immune infiltration, thereby diminishing oncogenesis. Our results provide a basis to interpret clinical evidence that elevated expression of GADD45B confers poor clinical outcomes in most human cancers. Further, they suggest a therapeutic target in GADD45β for re-programming TAM to overcome immunosuppression and T cell exclusion from the TME