CAR-NK cells for acute myeloid leukemia immunotherapy: past, present and future

Acute myeloid leukemia (AML) is a deadly disease and the most common leukemia in adult with clonal heterogeneity and abnormity in myeloid lineages, which has been recognized with high morbidity and mortality attributes to the recurrence and resistance to chemotherapy. Numerous literatures have indicated the encouraging progress in allogeneic hematopoietic stem cell transplantation (allo-HSCT) and chimeric antigen receptor-transduced T (CAR-T) cells. However, the outcomes of recurrent and refractory AML (r/rAML) patients with current strategies are still unsatisfactory, which largely due to the matching restriction as well as adverse reactions, including graft-versus-host disease (GvHD), neurotoxicity and cytokine release syndrome (CRS). State-of-the-art literatures have indicated CAR-transduced NK (CAR-NK) cells for the management of diverse hematologic malignancies including AML, which are recognized as novel weapons for reinforcing the specificity and cytotoxicity of autogenous and allogeneic "off-the-shelf" NK cells dispense with prior sensitization. Therefore, in this review, we mainly focus on the latest updates of alternative cell sources, therapeutic targets, CAR-modification and delivery strategies, standardization and productization, together with prospective and challenges of CAR-NK cell-based cytotherapy, which will collectively benefit the further development of novel treatment paradigms for combating AML via both CAR-dependent and NK cell receptor-dependent signaling cascades in future.