Grandjean F, Brémaud L, Verdier M, Robert J, Ratinaud MH. Sequential gene expression of P-glycoprotein (P-gp), multidrug resistance-associated protein (MRP) and lung resistance protein: functional activity of P-gp and MRP present in the doxorubicin-resistant human K562 cell lines.
Anticancer Drugs 2001;
12:247-58. [PMID:
11290872 DOI:
10.1097/00001813-200103000-00010]
[Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Previous studies have reported that P-glycoprotein (P-gp), a transmembrane efflux pump involved in multidrug resistance (MDR), was overexpressed in the doxorubicin (Dox)-resistant human erythroleukemia cell line K562. Nevertheless, several results suggested that P-gp was not the only mechanism involved in these resistant cells. Sequential co-expression of other MDR-associated proteins was sometimes reported, as MDR-associated protein (MRP) and lung resistance protein (LRP), in different MDR cell lines. Thus, mRNA expression and stability of P-gp, MRP and LRP were analyzed, while their corresponding protein levels were quantified in correlation with functional assay, in the K562 cell line and two Dox-resistant variants (K562/R). Their P-gp content was in accordance with their degree of resistance, but not as much in the level of mRNA expression, suggesting a post-transcriptional regulation. On the other hand, MRP could play a minor role in MDR because of an unchanged expression in K562/R sublines. A surprising progressive disappearance of LRP in both resistant cells suggested that the original mechanism of drug redistribution may be operative, involving a negative role for LRP.
Collapse