“GRK2 and Histamine H2 receptor as molecular targets for Acute Myeloid Leukemia”

EMILIANA ECHEVERRÍA; CARLOS DAVIO; GISELA GÓMEZ; MAXIMILIANO DE SOUSA SERRO; CARINA SHAYO; ANA SAHORES; NATALIA FERNÁNDEZ

Mar del Plata

Congreso; SAIC; 2023

SAIC

Previously we demonstrated that increases in intracellular cAMP play an important role in acute myeloid leukemia (AML) cell proliferation/differentiation. In this regard, histamine (Hist), through H2 receptor (H2R), stimulates rises cAMP levels but fails to promote cell differentiation due to the rapid H2R desensitization (DES) mediated by GRK2. Structurally, GRKs possess an RGS-homology domain (RH) responsible for G-protein activity regulation, a kinase domain engaged in receptor phosphorylation, and a region responsible for membrane localization. Through a docking-based strategy, we identified GRK2 inhibitors of the RGS domain of GRK2 with the ability to interfere with phosphorylation-independent actions of the RHGRK2. The aim of this study was to evaluate the effect of combining Hist treatment combining treatment with Hist together with GRK2 inhibitors targeting different domains, on the proliferation of AML cell models. We selected compounds that exhibited inhibitory DES activity towards Gαs-GPCRs (C3 and C5) or Gαq (C5 and C13) in the screening model, and CMPD as a commercially available GRK2-kinase inhibitor. First, we assessed U937 and HL60 cell proliferation after 72h treatment with 100µM Hist and different concentrations of GRK2 inhibitors, either by cell count or by using Incucyte® cell imaging. We detected a concentration-dependent anti-proliferative effect of C3, C5, and CMPD, with Histamine enhancing the effect of C3 and CMPD effect (p< 0.05). In order to confirm the mechanism of action of the compounds, Next, we evaluated their capacity of the selected compounds to inhibit the DES of the cAMP response induced by 30 min Histamine treatment in U937 cells. C3 and CMPD showed proved an increase in the Hist-histamine remaining response (p< 0.05), indicating the activity of the compounds. We also explored public dataset of AML demonstrating co-expression of H2R and GRK2 in all AML subtypes. However, no correlation was detected between GRK2 levels expression and patient survival. In summary, our results contribute to the rational basis of a polypharmacological approach in AML using Histamine and GRK2 inhibitors, which deserves further investigation.