Chronic ER Stress Induced of Cell-surface Chaperones as the Therapeutic Targets of CAR Cells in Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is a heterogeneous disease characterized by a clonal expansion of myeloid progenitors that affects the bone marrow. Despite advancements, survival rates of the treatments for AML remain still low, due to the heterogeneity and lack of specific targets, necessitating new precision therapies. Through integrative cell surface proteomes and cell biology analyses, we identified various potential neoantigens including endoplasmic reticulum (ER) chaperone proteins forced by chronically oncogenic stress, translocated to cell surfaces of AML subtype (e.g., FLT3-ITD+ AMLs), making them as promising diagnostic markers and therapeutic targets. As proof-of-concept, we then engineered chimeric antigen receptor (CAR) natural killer (NK) cells to target cell surface localized HSP90B1, a representative ER resided chaperone protein, showing selective killing of csHSP90B1-positive AML cells in vitro and in animal models. Single-cell transcriptional analyses further revealed heterogeneous landscapes of myeloid lineage differentiation and uncovered a therapeutic window targeting the identified AML cell cluster with novel characteristics of adaptive oncogenic stress to eradicate these malignant cells via immunotherapeutic interventions. Collectively, our findings not only identify several neoantigens as the specific biomarkers for refining AML patient classification, but also hold a significant promise for AML precision treatment through using immunotherapy approaches.