A major chromatin regulator determines resistance of tumor cells to T cell-mediated killing.
Pan D, Kobayashi A, Jiang P, Ferrari de Andrade L, Tay RE, Luoma AM, Tsoucas D, Qiu X, Lim K, Rao P, Long HW, Yuan GC, Doench J, Brown M, Liu XS, Wucherpfennig KW
Many human cancers are resistant to immunotherapy, for reasons that are poorly understood. We used a genome-scale CRISPR-Cas9 screen to identify mechanisms of tumor cell resistance to killing by cytotoxic T cells, the central effectors of antitumor immunity. Inactivation of >100 genes-including , , and , which encode components of the PBAF form of the SWI/SNF chromatin remodeling complex-sensitized mouse B16F10 melanoma cells to killing by T cells. Loss of PBAF function increased tumor cell sensitivity to interferon-γ, resulting in enhanced secretion of chemokines that recruit effector T cells. Treatment-resistant tumors became responsive to immunotherapy when was inactivated. In many human cancers, expression of and inversely correlated with expression of T cell cytotoxicity genes, and -deficient murine melanomas were more strongly infiltrated by cytotoxic T cells.