Euphorbia Pekinensis Rupr. sensitizes colorectal cancer to PD-1 blockade by remodeling the tumor microenvironment and enhancing peripheral immunity

Immune checkpoint blockade, such as monoclonal antibodies targeting programmed cell death protein 1 (PD-1), has been a major breakthrough in the treatment of several cancers, but has limited effect in colorectal cancer (CRC), which is a highly prevalent cancer worldwide. Current chemotherapy-based strategies to boost PD-1 response have many limitations. And the role of peripheral immunity in boosting PD-1 response continues to attract attention. Therefore, candidate combinations of PD-1 blockade need to be drugs with multi-targets and multi-modulatory functions. However, it is still unknown whether traditional Chinese medicines with such property can enhance the applicability and efficacy of PD-1 blockade in colorectal cancer.