PMID: 11309308Apr 20, 2001Paper

Subcellular localization and distribution of the breast cancer resistance protein transporter in normal human tissues

Cancer Research
M MaliepaardJ H Schellens

Abstract

High expression of the Breast Cancer Resistance Protein (BCRP) gene has been shown to be involved in resistance to chemotherapeutic drugs. Knowledge of the localization of BCRP protein in normal tissues may help unravel the normal function of this protein. Therefore, we characterized the tissue distribution and cellular localization of BCRP in frozen sections of normal human tissues. For this purpose, we used the recently described monoclonal antibody BXP-34 and another independently developed monoclonal antibody directed against BCRP, BXP-21. Both monoclonal antibodies show specific BCRP plasma membrane staining on cytospins obtained from topotecan- or mitoxantrone-selected cell lines, as well as from BCRP-transfected cell lines. Immunoprecipitation experiments using either BXP-21 or BXP-34 yielded a clear M(r) 72,000 BCRP band from BCRP-overexpressing tumor cells. In the topotecan-selected T8 and mitoxantrone-selected MX3 tumor cell lines, BCRP turned out to be differentially glycosylated. In contrast to BXP-34, BXP-21 is able to detect the M(r) 72,000 BCRP protein on immunoblots and is reactive with BCRP in formalin-fixed, paraffin-embedded tissues. Using BXP-21 and BXP-34, prominent staining of BCRP was observed in placenta...Continue Reading

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