HISTAMINE H2 RECEPTOR AND MRP4/ABCC4 AS MOLECULAR TARGETS FOR ACUTE MYELOID LEUKEMIA

MAY, MARIA; SHAYO, CARINA; RODRÍGUEZ GONZÁLEZ, ANGELA; DI SIERVI, NICOLÁS; SAHORES, ANA; DAVIO, CARLOS

Mar del Plata

Congreso; Reunión Anual de la Sociedad Argentina de Investigación Clínica; 2019

SAIC

Acute myeloid leukemia (AML) is a heterogeneous clonal disorder in which early hematopoietic cells fail to differentiate and do not undergo programmed cell death nor apoptosis. We previously showed that increments in intracellular cAMP levels play an important role in leukemic cell proliferation and differentiation. Histamine, through H2 receptor (H2R), stimulates cAMP formation and up-regulates MRP4 expression, responsible for cAMP efflux. The aim of this study was to evaluate the effect of combining treatment with H2R agonists, histamine (HDC) or amthamine (A), together with a MRP4 inhibitor (ceefourin1) or non-specific MRP4 inhibitors (probenecid and MK571) upon proliferation and differentiation of AML cell models. U937, HL60 and KG1a cell proliferation after 72h treatment with 100µM HDC or 10µM A and different concentrations of MRP4 inhibitors was assessed by cell count. H2R stimulation enhanced the concentration-dependent anti-proliferative effect of MRP4 inhibitors. Next, CD88 expression was evaluated by western blot, as an AML terminal differentiation marker. HDC and A in combination with MK571 or probenecid augmented CD88 expression compared to single treatments. In accordance, c-Myc expression was down-regulated to a greater extent in the combined treatment. However, neither ceefourin1 nor its combined treatments induced CD88 expression, but induced apoptotic markers (caspase-3 and PARP activation). To evaluate the effect of ceefourin1 on leukemia cell proliferation in vivo, Swiss nu/nu mice were subcutaneously injected with U937 cells. Mice were treated with ceefourin1 for 3 weeks (ip, 10mg/kg daily), xenografts were measured periodically and their morphology was assessed by H&E staining. Although tumor growth was not affected, a significant increase in the apoptotic index was observed in mice treated with ceefourin1. Taken together, our results contribute to the rational basis of a polypharmacological approach in AML using H2R ligands and MRP4 inhibitors.