CSTF2-impeded innate αβ T cell infiltration and activation exacerbate immune evasion of pancreatic cancer.

Alternative cleavage and polyadenylation (APA) have gained increasing attention in cancer biology, yet its role in modulating anti-tumor immune response remains largely unexplored. Here, we identify the cleavage stimulation factor 2 (CSTF2), an APA-related gene, as a pivotal suppressor of anti-tumor immunity in pancreatic ductal adenocarcinoma (PDAC). CSTF2 promotes tumor development by inhibiting the infiltration and cytotoxic immune cell recruitment function of TCRαβCD4CD8NK1.1 innate αβ T (iαβT) cells. Mechanistically, CSTF2 diminishes CXCL10 expression by promoting PolyA polymerase alpha (PAPα) binding to the 3' untranslated regions of CXCL10 RNA, resulting in shortened PolyA tails and compromised RNA stability. Furthermore, we identify Forsythoside B, a selective inhibitor targeting the RNA recognition motif of CSTF2, can effectively activate anti-tumor immunity and overcome resistance to immune checkpoint blockade (ICB) therapy. Collectively, our findings unveil CSTF2 as a promising therapeutic target for sensitizing PDAC to ICB therapy.