TY - JOUR
T1 - Functional characterization of wild-type and 49 CYP2D6 allelic variants for N-desmethyltamoxifen 4-hydroxylation activity
AU - Muroi, Yuka
AU - Saito, Takahiro
AU - Takahashi, Masamitsu
AU - Sakuyama, Kanako
AU - Niinuma, Yui
AU - Ito, Miyabi
AU - Tsukada, Chiharu
AU - Ohta, Kiminori
AU - Endo, Yasuyuki
AU - Oda, Akifumi
AU - Hirasawa, Noriyasu
AU - Hiratsuka, Masahiro
N1 - Funding Information:
Received February 5, 2014; Accepted March 9, 2014 J-STAGE Advance Published Date: March 18, 2014, doi:10.2133/dmpk.DMPK-14-RG-014 *To whom correspondence should be addressed: Masahiro HIRATSUKA, Ph.D., Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3 Aoba Aramaki, Aoba-ku, Sendai 980-8578, Japan. Tel.©81-22-717-7049, Fax. ©81-22-717-7049, E-mail: mhira@m.tohoku.ac.jp This work was supported in part by grants from the Ministry of Health, Labour and Welfare (MHLW) of Japan (‘Initiative to facilitate development of innovative study, medical devices, and cellular & tissue-based product’), Smoking Research Foundation, and Japan Research Foundation for Clinical Pharmacology.
Publisher Copyright:
Copyright © 2014 by the Japanese Society for the Study of Xenobiotics (JSSX).
PY - 2014
Y1 - 2014
N2 - Genetic variations in cytochrome P450 2D6 (CYP2D6) contribute to interindividual variability in the metabolism of clinically used drugs, e.g., tamoxifen. CYP2D6 is genetically polymorphic and is associated with large interindividual variations in therapeutic efficacy and drug toxicity. In this study, we performed an in vitro analysis of 50 allelic variants of CYP2D6 proteins. Wild-type CYP2D6.1 and 49 variants were transiently expressed in COS-7 cells, and the enzymatic activities of the CYP2D6 variants were characterized using N-desmethyltamoxifen as a substrate. The kinetic parameters Km, Vmax, and intrinsic clearance (Vmax/Km) of N-desmethyltamoxifen 4-hydroxylation were determined. Among the 50 CYP2D6 variants, the kinetic parameters for N - desmethyltamoxifen 4-hydroxylation were determined for 20 CYP2D6 variants. On the other hand, the kinetic parameters of 30 CYP2D6 variants could not be determined because the amount of metabolite produced was at or below the detection limit at the lower substrate concentrations. Among them, 8 variants, i.e., CYP2D6.2, .9, .26, .28, .32, .43, .45, and .70, showed decreased intrinsic clearance at <50% of CYP2D6.1. The comprehensive in vitro assessment of CYP2D6 variants provides novel insights into allele-specific activity towards tamoxifen and may be valuable when interpreting in vivo studies.
AB - Genetic variations in cytochrome P450 2D6 (CYP2D6) contribute to interindividual variability in the metabolism of clinically used drugs, e.g., tamoxifen. CYP2D6 is genetically polymorphic and is associated with large interindividual variations in therapeutic efficacy and drug toxicity. In this study, we performed an in vitro analysis of 50 allelic variants of CYP2D6 proteins. Wild-type CYP2D6.1 and 49 variants were transiently expressed in COS-7 cells, and the enzymatic activities of the CYP2D6 variants were characterized using N-desmethyltamoxifen as a substrate. The kinetic parameters Km, Vmax, and intrinsic clearance (Vmax/Km) of N-desmethyltamoxifen 4-hydroxylation were determined. Among the 50 CYP2D6 variants, the kinetic parameters for N - desmethyltamoxifen 4-hydroxylation were determined for 20 CYP2D6 variants. On the other hand, the kinetic parameters of 30 CYP2D6 variants could not be determined because the amount of metabolite produced was at or below the detection limit at the lower substrate concentrations. Among them, 8 variants, i.e., CYP2D6.2, .9, .26, .28, .32, .43, .45, and .70, showed decreased intrinsic clearance at <50% of CYP2D6.1. The comprehensive in vitro assessment of CYP2D6 variants provides novel insights into allele-specific activity towards tamoxifen and may be valuable when interpreting in vivo studies.
KW - CYP2D6
KW - Cytochrome P450
KW - Drug metabolism
KW - Genetic polymorphisms
KW - Pharmacogenomics
KW - Tamoxifen
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U2 - 10.2133/dmpk.DMPK-14-RG-014
DO - 10.2133/dmpk.DMPK-14-RG-014
M3 - Article
C2 - 24647041
AN - SCOPUS:84908241988
VL - 29
SP - 360
EP - 366
JO - Drug Metabolism and Pharmacokinetics
JF - Drug Metabolism and Pharmacokinetics
SN - 1347-4367
IS - 5
ER -