1.knocking out mediated by CRISPR-Cas9 genome editing for PD-L1 attenuation and enhanced antitumor immunity.
Huan DENG ; Songwei TAN ; Xueqin GAO ; Chenming ZOU ; Chenfeng XU ; Kun TU ; Qingle SONG ; Fengjuan FAN ; Wei HUANG ; Zhiping ZHANG
Acta Pharmaceutica Sinica B 2020;10(2):358-373
Blocking the programmed death-ligand 1 (PD-L1) on tumor cells with monoclonal antibody therapy has emerged as powerful weapon in cancer immunotherapy. However, only a minority of patients presented immune responses in clinical trials. To develop an alternative treatment method based on immune checkpoint blockade, we designed a novel and efficient CRISPR-Cas9 genome editing system delivered by cationic copolymer aPBAE to downregulate PD-L1 expression on tumor cells specifically knocking out Cyclin-dependent kinase 5 () gene . The expression of PD-L1 on tumor cells was significantly attenuated by knocking out , leading to effective tumor growth inhibition in murine melanoma and lung metastasis suppression in triple-negative breast cancer. Importantly, we demonstrated that aPBAE/Cas9-Cdk5 treatment elicited strong T cell-mediated immune responses in tumor microenvironment that the population of CD8 T cells was significantly increased while regulatory T cells (Tregs) was decreased. It may be the first case to exhibit direct PD-L1 downregulation CRISPR-Cas9 genome editing technology for cancer therapy. It will provide promising strategy for preclinical antitumor treatment through the combination of nanotechnology and genome engineering.