Zbtb32 promotes CD8+ T cell differentiation and function in cancer

In the tumor microenvironment (TME), "exhausted" CD8+ T cells are classified into progenitor (Tpex) and terminally exhausted (Ttex) populations. Tpex cells, critically regulated by zinc finger and BTB domain containing 27 (Zbtb27)/Bcl6 transcription factor, could be reinvigorated during immune checkpoint blockade (ICB) therapy, while Ttex cells, characterized by stronger proliferation and cytotoxicity, play an indispensable role in tumor control. However, the mechanisms governing the differentiation into Ttex and their function remain not well understood. In this study, we identified that Zbtb32, highly expressed in CD8+ Ttex subset, is crucial for CD8+ T cells within tumors. Zbtb32, regulated by CD28 signaling, promotes the differentiation of CD8+ T cells into Ttex subset, enhancing their cytotoxicity, proliferation, and anti-tumor capability. Importantly, we found a competitive DNA binding between Zbtb32 and Bcl6, especially in regulation of Id2 expression. Thus, our findings demonstrate the pivotal role of Zbtb32 in CD8+ T cell anti-tumor function, with implications in cancer immunotherapy.