CISH 敲除增强人 T 细胞抗肿瘤活性并降低 PD-1 表达水平

Tumor cells and the immunosuppressive tumor microenvironment suppress the antitumor activity of T cells through immune checkpoints, including the PD-L1/PD-1 axis. Cytokine-inducible SH2-containing protein (CISH), a member of the suppressor of cytokine signaling (SOCS) family, inhibits JAK-STAT and T cell receptor (TCR) signaling in T and natural killer (NK) cells.

However, its role in the regulation of immune checkpoints in T cells remains unclear. In this study, we ablated CISH in T cells with CRISPR-Cas9 and found that the sensitivity of T cells to TCR and cytokine stimulation was increased.

In addition, chimeric antigen receptor T cells with CISH deficiency exhibited longer survival and higher cytokine secretion and antitumor activity.

Notably, PD-1 expression was decreased in activated CISH-deficient T cells in vitro and in vivo . The level of FBXO38, a ubiquitination-regulating protein that reduces PD-1 expression, was elevated in activated T cells after CISH ablation. Hence, this study reveals a mechanism by which CISH promotes PD-1 expression by suppressing the expression of FBXO38 and proposes a new strategy for augmenting the therapeutic effect of CAR-T cells by inhibiting CISH.