TY - JOUR
T1 - Pharmacogenetics of deoxycytidine kinase
T2 - Identification and characterization of novel genetic variants
AU - Lamba, Jatinder K.
AU - Crews, Kristine
AU - Pounds, Stanley
AU - Schuetz, Erin G.
AU - Gresham, Jessica
AU - Gandhi, Varsha
AU - Plunkett, William
AU - Rubnitz, Jeffrey
AU - Ribeiro, Raul
PY - 2007/12
Y1 - 2007/12
N2 - Deoxycytidine kinase (DCK) is a rate-limiting enzyme in the activation of nucleoside analogs such as cytarabine (ara-C), gemcitabine, clofarabine, and others. The present study was undertaken to identify and to determine the functional consequences of genetic variants in DCK. We sequenced 1.5 kilobases of the DCK proximal promoter and all seven coding exons in International HapMap Project panels (n = 90 each) with European (Centre d' Etude du Polymorphisme Humain; CEPH) or African (Yoruba people in Ibadan, Nigeria; YRI) ancestry. Sixty-four genetic polymorphisms, including three nonsynonymous coding changes (I24V, A119G, and P122S) were identified. Compared with DCK-wild-type (WT) protein, the activity of the recombinant DCK24Val, DCK119Gly, and DCK122Ser proteins was 85 ± 5, 66 ± 3, and 43 ± 4%, respectively. DCK119Gly and DCK122Ser mutants had lower Km (p < 0.01) and V max (p < 0.001) compared with DCK-WT protein. Lymphoblast cell lines from subjects heterozygous for the coding changes had significantly lower DCK activity compared with homozygous WT subjects. Ethnic differences were observed, with African ancestry subjects demonstrating significantly higher DCK mRNA expression compared with subjects with European ancestry. In both CEPH and YRI subjects, the C allele of a 3′-untranslated region singlenucleotide polymorphism (SNP) (35708 C>T) was significantly associated with lower DCK mRNA expression. This SNP was strongly linked with other intronic SNPs, forming a major haplotype block in both ethnic groups. In an exploratory analysis, the 35708C allele was also associated with lower blast ara-C-5′-triphosphate (ara-CTP) levels in acute myeloid leukemia patients receiving ara-C as continuous infusion. These results suggest that genetic variation in DCK influences its activity and expression and may predict the variability observed in intracellular levels of the ara-C active metabolite ara-CTP.
AB - Deoxycytidine kinase (DCK) is a rate-limiting enzyme in the activation of nucleoside analogs such as cytarabine (ara-C), gemcitabine, clofarabine, and others. The present study was undertaken to identify and to determine the functional consequences of genetic variants in DCK. We sequenced 1.5 kilobases of the DCK proximal promoter and all seven coding exons in International HapMap Project panels (n = 90 each) with European (Centre d' Etude du Polymorphisme Humain; CEPH) or African (Yoruba people in Ibadan, Nigeria; YRI) ancestry. Sixty-four genetic polymorphisms, including three nonsynonymous coding changes (I24V, A119G, and P122S) were identified. Compared with DCK-wild-type (WT) protein, the activity of the recombinant DCK24Val, DCK119Gly, and DCK122Ser proteins was 85 ± 5, 66 ± 3, and 43 ± 4%, respectively. DCK119Gly and DCK122Ser mutants had lower Km (p < 0.01) and V max (p < 0.001) compared with DCK-WT protein. Lymphoblast cell lines from subjects heterozygous for the coding changes had significantly lower DCK activity compared with homozygous WT subjects. Ethnic differences were observed, with African ancestry subjects demonstrating significantly higher DCK mRNA expression compared with subjects with European ancestry. In both CEPH and YRI subjects, the C allele of a 3′-untranslated region singlenucleotide polymorphism (SNP) (35708 C>T) was significantly associated with lower DCK mRNA expression. This SNP was strongly linked with other intronic SNPs, forming a major haplotype block in both ethnic groups. In an exploratory analysis, the 35708C allele was also associated with lower blast ara-C-5′-triphosphate (ara-CTP) levels in acute myeloid leukemia patients receiving ara-C as continuous infusion. These results suggest that genetic variation in DCK influences its activity and expression and may predict the variability observed in intracellular levels of the ara-C active metabolite ara-CTP.
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U2 - 10.1124/jpet.107.128595
DO - 10.1124/jpet.107.128595
M3 - Article
C2 - 17855478
AN - SCOPUS:36348945304
SN - 0022-3565
VL - 323
SP - 935
EP - 945
JO - Journal of Pharmacology and Experimental Therapeutics
JF - Journal of Pharmacology and Experimental Therapeutics
IS - 3
ER -