MDR1 (ABCB1) G1199A (Ser400Asn) polymorphism alters transepithelial permeability and sensitivity to anticancer agents
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P-glycoprotein (P-gp), encoded by MDR1 (or ABCB1), is important in anticancer drug delivery and resistance. We evaluated alterations in P-gp-mediated transport of anticancer agents due to the MDR1 G1199A polymorphism.
Using stable recombinant epithelial cells expressing wild-type (MDR1 wt ) or G1199A (MDR1 1199A ), anticancer drug sensitivity and transepithelial permeability were evaluated.
The recombinant cells MDR1 wt and MDR1 1199A displayed comparable doxorubicin resistance. However, MDR1 1199A cells displayed greater resistance to vinblastine, vincristine, paclitaxel, and VP-16 (11-, 2.9-, 1.9-, and 2.9-fold, respectively). Alterations in transepithelial permeability paralleled these changes. Efflux of doxorubicin was similar between MDR1 wt - and MDR1 1199A -expressing cells, while P-gp-mediated transport was greater for vinblastine and vincristine in MDR1 1199A cells (2.9- and 2.0-fold, respectively).
The occurrence and magnitude of the MDR1 G1199A effect is drug specific. Overall, the MDR1 G1199A polymorphism may impact anticancer efficacy through modulation of drug distribution and delivery to target tumor cells.
KeywordsMDR1 ABCB1 P-Glycoprotein Pharmacogenomics Cancer chemotherapy Transepithelial permeability
- MDR1 or ABCB1
Multidrug resistance gene
Single nucleotide polymorphism
MDR1 G1199A polymorphism
Effective drug concentration necessary for 50% cell death
Transepithelial electrical resistance values
Apical-to-basolateral apparent permeability
Basolateral-to-apical apparent permeability
Supported in part by NIH grants GM62883, AI52663, NS39178, ES07033, and HL56548. ELW is a recipient of the NIH Pharmaceutical Sciences Training Grant (GM07750), and the William E. Bradley Fellowship in Pharmaceutics. Sequencing work was supported by the University School of Pharmacy DNA Sequencing and Gene Analysis Center. RJYH is also supported by the Milo Gibaldi Endowment.
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