Role of drug transporters in the sensitivity of acute myeloid leukemia to sorafenib

// Rocio I.R. Macias 1, 2 , Anabel Sanchez-Martin 1 , Gabriela Rodriguez-Macias 1, 3 , Luis I. Sanchez-Abarca 4 , Elisa Lozano 1, 2 , Elisa Herraez 1, 2 , Maria D. Odero 5 , Jose L. Diez-Martin 3, 6 , Jose J.G. Marin 1, 2, * and Oscar Briz 1, 2, * 1 Laboratory of Experimental Hepatology and Drug Targeting (HEVEFARM), University of Salamanca, IBSAL, Salamanca, Spain 2 National Institute for the Study of Liver and Gastrointestinal Diseases (CIBERehd), Madrid, Spain 3 Department of Hematology-BMT Unit, Hospital General Universitario Gregorio Maranon, Madrid, Spain 4 Department of Hematology, University Hospital of Salamanca, IBSAL, Salamanca, Spain 5 Department of Biochemistry and Genetics and CIMA, University of Navarra, Pamplona, CIBERONC, Spain 6 Gregorio Maranon Institute for Health Research (IISGM), Madrid, Spain * These authors have contributed equally to this work Correspondence to: Rocio I.R. Macias, email: rociorm@usal.es Keywords: AML; cancer; chemoresistance; chemotherapy; tyrosine kinase inhibitor Received: December 21, 2017     Accepted: April 24, 2018     Published: ABSTRACT Background : Chemoresistance often limits the success of the pharmacological treatment in acute myeloid leukemia (AML) patients. Although positive results have been obtained with tyrosine kinase inhibitors (TKIs), such as sorafenib, especially in patients with Fms-like tyrosine kinase 3 (FLT3)-positive AML, the success of chemotherapy is very heterogeneous. Here we have investigated in vitro whether the transportome (set of expressed plasma membrane transporters) is involved in the differential response of AML to sorafenib. Methods : The sensitivity to sorafenib-induced cell death (MTT test and anexin V/7-AAD method) was evaluated in five different cell lines: MOLM-13, OCI-AML2, HL-60, HEL and K-562. The transportome was characterized by measuring mRNA using RT-qPCR. Drug uptake/efflux was determined by flow cytometry using specific substrates and inhibitors. Results : The cytostatic response to sorafenib was: MOLM-13>>OCI-AML2>HL-60>HEL≈K-562. Regarding efflux pumps, MDR1 was highly expressed in HEL>K-562≈MOLM-13, but not in OCI-AML2 and HL-60. BCRP and MPR3 expression was low in all cell lines, whereas MRP4 and MRP5 expression was from moderate to high. Flow cytometry studies demonstrated that MRP4, but not MRP5, was functional. The expression of the organic cation transporter 1 (OCT1), involved in sorafenib uptake, was MOLM-13>OCI-AML2≈HL-60 and non detectable in HEL and K-562. Transfection of HEL cells with OCT1 increased the sensitivity of these cells to sorafenib, whereas inactive genetic variants failed to induce this change. Conclusion: Together with changes in the expression/function of receptors targeted by TKIs, the expression of plasma membrane transporters involved in sorafenib uptake/efflux may affect the response of leukemia cells to this drug.