title: P-glycoprotein efflux pump plays an important role in Trypanosoma cruzi drug resistance.
abstract: Drug resistance in protozoan parasites has been associated with the P-glycoprotein (Pgp), an energy-dependent efflux pump that transports substances across the membrane. Interestingly, the genes TcPGP1 and TcPGP2 have been described in Trypanosoma cruzi, although the function of these genes has not been fully elucidated. The main goal of this work was to investigate Pgp efflux pump activity and expression in T. cruzi lines submitted to in vitro induced resistance to the compounds 4-N-(2-methoxy styryl)-thiosemicarbazone (2-Meotio) and benznidazole (Bz) and to verify the stability of the resistant phenotypes during the parasite life cycle. We observed that the EC50 values for the treatment of epimastigotes with 2-Meotio or Bz were increased at least 4.7-fold in resistant lines, and this phenotype was maintained in metacyclic trypomastigotes, cell-derived trypomastigotes, and intracellular amastigotes. However, in epimastigotes, 2-Meotio resistance is reversible, but Bz resistance is irreversible. When compared with the parental line, the resistant lines exhibited higher Pgp efflux activity, reversion of the resistant phenotypes in the presence of Pgp inhibitors, cross-resistance with Pgp modulators, higher basal Pgp ATPase activity, and overexpression of the genes TcPGP1 and TcPGP2. In conclusion, the resistance induced in T. cruzi by the compounds 2-Meotio and Bz is maintained during the entire parasite life cycle. Furthermore, our data suggest the participation of the Pgp efflux pump in T. cruzi drug resistance.
authors.affiliation: Laboratório de Bioquímica de Tripanosomatídeos, Instituto Oswaldo Cruz, IOC, Avenida Brasil 4365, Manguinhos, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil. moncacaroline@yahoo.com.br
authors.forename: Mônica Caroline Oliveira
authors.initials: MC
authors.lastname: Campos
authors.forename: Denise Barçante
authors.initials: DB
authors.lastname: Castro-Pinto
authors.forename: Grazielle Alves
authors.initials: GA
authors.lastname: Ribeiro
authors.forename: Márcia Moreira
authors.initials: MM
authors.lastname: Berredo-Pinho
authors.forename: Leonardo Henrique Ferreira
authors.initials: LH
authors.lastname: Gomes
authors.forename: Myrtes Santos
authors.initials: MS
authors.lastname: da Silva Bellieny
authors.forename: Carla Marins
authors.initials: CM
authors.lastname: Goulart
authors.forename: Aurea
authors.initials: A
authors.lastname: Echevarria
authors.forename: Leonor Laura
authors.initials: LL
authors.lastname: Leon
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics / Q000378:metabolism*; D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism; D000981:Antiprotozoal Agents / Q000378:metabolism* / Q000494:pharmacology*; D004351:Drug Resistance; D020869:Gene Expression Profiling; D009593:Nitroimidazoles / Q000378:metabolism / Q000494:pharmacology; D015800:Protozoan Proteins / Q000378:metabolism*; D013882:Thiosemicarbazones / Q000378:metabolism / Q000494:pharmacology; D014349:Trypanosoma cruzi / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000981:Antiprotozoal Agents; D009593:Nitroimidazoles; D015800:Protozoan Proteins; D013882:Thiosemicarbazones; D000251:Adenosine Triphosphatases; C009999:benzonidazole