Sulfisoxazole Elicits Robust Antitumour Immune Response Along with Immune Checkpoint Therapy by Inhibiting Exosomal PD-L1.

ABSTRACT: Despite their potent antitumor activity, clinical application of immune checkpoint inhibitors has been significantly limited by their poor response rates (<30%) in cancer patients, primarily due to immunosuppressive tumor microenvironments. As a representative immune escape mechanism, cancer-derived exosomes have recently been demonstrated to exhaust CD8⁺ cytotoxic T cells. Here, it is reported that sulfisoxazole, a sulfonamide antibacterial, significantly decreases the exosomal PD-L1 level in blood when orally administered to the tumor-bearing mice. Consequently, sulfisoxazole effectively reinvigorates exhausted T cells, thereby eliciting robust antitumor effects in combination with anti-PD-1 antibody. Overall, sulfisoxazole regulates immunosuppression through the inhibition of

SUBMITTER: Shin JM 

PROVIDER: S-EPMC8844465 | biostudies-literature | 2022 Feb

REPOSITORIES: biostudies-literature