Therapy induced senescence promotes immunogenicity in acute myeloid Leukemia through reduced EZH2 activity

Chemotherapy resistance and disease relapse are major determinants of treatment failure in acute myeloid leukemia (AML). Therapy-induced senescence (TIS) is one outcome of chemotherapy, but its immunological consequences in AML remain unclear. Here we show that ex vivo chemotherapy induces senescence in a subset of therapy-naïve AML samples. TIS is marked by elevated interferon signaling, upregulation of human leukocyte antigen (HLA) class I and II molecules, and increased presentation of leukemia- and senescence-associated peptides, conferring AML cells antigen-presenting cell-like features. These changes enhance autologous CD4+ and CD8+ T cell responses against AML, both ex vivo and in patient-derived xenograft models. TIS also restores AML sensitivity to immune checkpoint blockade therapy. Mechanistically, we identify reduced Polycomb Repressive Complex 2 (PRC2) activity as central to TIS induction and its immunogenicity. PRC2 inhibition reactivates senescence-related genes and HLA expression in non-senescent AML cells, enabling T cell activation. These findings uncover a senescence-driven immune mechanism with potential to improve therapy outcomes in AML.