CRISPRa-identified transcription factors reprogram glioblastoma into dendritic cell-like cells to elicit systemic antitumor immunity

Although immunotherapy has transformed the treatment landscape for many types of cancer, its therapeutic efficacy in glioblastoma (GBM) is limited by insufficient antigen presentation and the immunogenic cell exclusion in the tumor microenvironment. Here, we develop a candidate-based CRISPR activation (CRISPRa) functional screen to identify regulators of conventional dendritic cell (cDC)-fate specification. We determine that the transcription factors Zfp366/Znf366, Pu.1, Irf8, and Batf3 (ZPIB) are sufficient to convert GBM cells into cDC-like cells. ZPIB-mediated reprogramming results in global transcriptional and epigenetic remodeling in glioma cells. Single-cell RNA sequencing (scRNA-seq) profiling also reveals efficient and dynamic reprogramming of GBM cells to cDCs in vivo. Moreover, reprogrammed tumor cells remodel the microenvironment and elicit systemic tumor-eradicating and durable antitumor immunity in multiple mouse GBM models. Antitumor immunity elicited by ZPIB-DCs is synergistic with immune checkpoint inhibitors. Finally, we evaluate the clinical applicability of this approach by generating ZPIB-DCs from GBM patients within a humanized model. Our study represents a cellular reprogramming therapeutic strategy with broad implications for clinical immunotherapy.