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Single nucleotide polymorphisms modify the transporter activity of ABCG2.
Kuniaki Morisaki1, Robert W Robey, Csilla Ozvegy-Laczka
1Cancer Therapeutics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 9000 Rockville Pike, Bldg 10 Rm 12C103, Bethesda, MD 20892, USA.
Cancer Chemotherapy and Pharmacology
|April 20, 2005
Summary
Single nucleotide polymorphism (SNP) Q141K in the ABCG2 gene significantly impacts drug transport and cellular efflux. This ABCG2 variant may alter drug resistance and pharmacokinetics in cancer patients.
Area of Science:
- Pharmacogenomics
- Molecular Biology
- Cell Biology
Background:
- The ABCG2 gene encodes a transporter protein crucial for drug efflux.
- Nonsynonymous single nucleotide polymorphisms (SNPs) can alter protein function and drug response.
- Understanding SNP effects on ABCG2 is vital for personalized oncology.
Purpose of the Study:
- To investigate the functional impact of ABCG2 SNPs (V12M, Q141K, D620N) on drug transport and ATPase activity.
- To determine if specific ABCG2 variants affect cellular drug resistance and protein localization.
Main Methods:
- Stable transfection of HEK-293 cells with wild-type and SNP variants of ABCG2.
- Cytotoxicity assays using anticancer drugs (mitoxantrone, topotecan, SN-38, diflomotecan).
- Measurement of drug efflux, vanadate-sensitive ATPase activity, and protein localization via confocal microscopy.
Main Results:
- The Q141K SNP significantly reduced mitoxantrone efflux and ATPase activity compared to wild-type ABCG2.
- Cells expressing Q141K ABCG2 showed altered sensitivity to certain chemotherapy drugs.
- V12M and D620N SNPs had minimal impact on ABCG2 function in HEK-293 cells, though V12M affected Hoechst 33342 transport in Sf9 cells.
Conclusions:
- The Q141K SNP in ABCG2 demonstrably affects drug transport efficiency and ATPase activity.
- Q141K variant may lead to altered pharmacokinetics and drug resistance profiles in cancer treatment.
- Further research into ABCG2 SNPs is warranted for optimizing cancer therapy.