Targeting RBPMS selectively eliminates FOXO1-mediated stem cell signatures in mouse models of acute myeloid leukemia

Leukemia is a malignant tumor with a high recurrence rate and poor prognosis for patients. Thus, there is an urgent need to explore new therapeutic targets that play critical roles in leukemogenesis but have little effect on normal hematopoietic cells. Here, we show that RNA binding protein with multiple splicing (RBPMS), which is highly expressed in acute myeloid leukemia (AML) and associated with poor prognosis of AML, plays critical roles in leukemogenesis. Our study shows that inhibition of RBPMS inhibits self-renewal of leukemia-initiating cells (LICs) and leukemia development but has little effect on normal hematopoiesis. Mechanistically, RBPMS recruits the N⁶-methyladenosine (m⁶A) reader insulin-like growth factor 2 mRNA binding protein 3 (IGF2BP3), which promotes the stability of the forkhead box O1 (FOXO1) mRNA in an m⁶A-dependent manner. Moreover, RBPMS contributes to the progression of leukemia by directly binding to FOXO1 and promoting FOXO1-regulated glycolysis. Overexpression of FOXO1 has been shown to reverse RBPMS inhibition-induced phenotypes in both leukemic cells and mouse models. We also designed a specific inhibitor of RBPMS that has therapeutic effects in AML patient-derived xenograft (PDX) models. We therefore highlight RBPMS as a promising drug target for leukemia therapy.