title: Contrasting features of MDR phenotype in leukemias by using two fluorochromes: implications for clinical practice.
abstract: The expression and activity of P-glycoprotein (Pgp) and multidrug resistance-associated protein (MRP1) were analyzed in 178 leukemia samples. Rhodamine-123 (Rho-123) and DiOC(2) were used as substrate to evaluate efflux pump activity. Chronic myeloid leukemia (CML) exhibited a higher percentage of positivity using Rho-123 than DiOC(2) (p=0.000) as compared to other types of leukemia. Moreover, Rho-123 was able to detected Pgp positive cells in a higher proportion of samples than DiOC(2) samples (p=0.004). Similarly, MRP1 positive cells were best detected by Rho-123 as opposed to DiOC(2) (p=0.003). The co-functionality of Rho-123 and DiOC(2) was observed in 26 out of 105 (24.8%) leukemic samples. Co-expression between Pgp and MRP1 was detected in 30 out of 56 (53.6%) samples. As a whole, when the same samples were analyzed, Rho-123 was able to detect Pgp positive cells in a higher proportion of samples than DiOC(2) (p=0.000). Similarly, MRP1 positive cells were best detected by Rho-123 as opposed to DiOC(2) (p=0.007). Our results support the idea that Rho-123 is the substrate of choice for leukemic cells.
authors.affiliation: Laboratório de Hematologia Celular e Molecular, Serviço de Hematologia, Hospital do Câncer (HC-I), Instituto Nacional de Câncer (INCA), Rio de Janeiro-RJ, Brazil.
authors.forename: Flavia C
authors.initials: FC
authors.lastname: Vasconcelos
authors.forename: Geraldo B
authors.initials: GB
authors.lastname: Cavalcanti
authors.forename: Karina L
authors.initials: KL
authors.lastname: Silva
authors.forename: Ernesto
authors.initials: E
authors.lastname: de Meis
authors.forename: Jolie K
authors.initials: JK
authors.lastname: Kwee
authors.forename: Vivian M
authors.initials: VM
authors.lastname: Rumjanek
authors.forename: Raquel C
authors.initials: RC
authors.lastname: Maia
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism*; D002232:Carbocyanines / Q000378:metabolism; D018432:Drug Resistance, Multiple; D019008:Drug Resistance, Neoplasm; D005434:Flow Cytometry; D005456:Fluorescent Dyes / Q000378:metabolism*; D006801:Humans; D007938:Leukemia / Q000188:drug therapy / Q000378:metabolism*; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000188:drug therapy / Q000378:metabolism; D015470:Leukemia, Myeloid, Acute / Q000188:drug therapy / Q000378:metabolism; D015473:Leukemia, Promyelocytic, Acute / Q000188:drug therapy / Q000378:metabolism; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000378:metabolism*; D010641:Phenotype; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000188:drug therapy / Q000378:metabolism; D020112:Rhodamine 123 / Q000378:metabolism; D014407:Tumor Cells, Cultured
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D002232:Carbocyanines; D005456:Fluorescent Dyes; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D020112:Rhodamine 123; C007392:3,3'-dihexyl-2,2'-oxacarbocyanine; C421109:multidrug resistance-associated protein 1