Function of the ABC transporters, P-glycoprotein, multidrug resistance protein and breast cancer resistance protein, in minimal residual disease in acute myeloid leukemia.
| Autor: | van der Pol MA; Department of Hematology, VU University Medical Center, Amsterdam, The Netherlands., Broxterman HJ, Pater JM, Feller N, van der Maas M, Weijers GW, Scheffer GL, Allen JD, Scheper RJ, van Loevezijn A, Ossenkoppele GJ, Schuurhuis GJ |
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| Jazyk: | angličtina |
| Zdroj: | Haematologica [Haematologica] 2003 Feb; Vol. 88 (2), pp. 134-47. |
| Abstrakt: | Background and Objectives: Relapse is common in acute myeloid leukemia (AML) because of persistence of minimal residual disease (MRD). ABC-transporters P-glycoprotein (Pgp) and multidrug resistance protein (MRP), are thought to contribute to treatment failure, while it is unknown whether breast cancer resistance protein (BCRP) does so. However, whether up-regulation of pump activity or selection of subpopulations with higher pump activity occurs during chemotherapy is unclear. The aim of this study was to elucidate whether ABC-transporter function changes during the course of disease. Design and Methods: MRD cells were identified using leukemia-associated phenotypes combined with a fluorescent probe assay with substrate/modulator: Syto16/ PSC833 (Pgp), calcein-AM/probenecid (MRP) and BODIPY-prazosin/Ko143 (BCRP); efflux profiles were directly compared with blasts at diagnosis and relapse from the same patient. Results: At diagnosis BCRP activity was undetectable in AML blasts from 23/26 cases, while Pgp activity was present in 36/45 and MRP activity in 26/44 of the cases. Furthermore, no subpopulations of blasts with considerably higher drug efflux capacities were found. Overall, no consistent changes were observed at follow-up [during chemotherapy (n=20), MRD (n=37), relapse (n=26))] in forty-five patients, the mean activities (as percentages of values at diagnosis) were 97% (Pgp), 103% (MRP) and 102% (BCRP). Interpretation and Conclusions: Emergence of MRD is thus not accompanied by either upregulation of ABC-transporter function during or after chemotherapy or by selection of pre-existing highly resistant subpopulations. The prognostic value of Pgp and MRP is, therefore, likely related to drug efflux capacity homogeneously distributed in the whole blast population, while BCRP probably has a limited function in drug efflux-related resistance in AML. |
| Databáze: | MEDLINE |
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