Identification of the promoter of human carbonyl reductase 3 (CBR3) and impact of common promoter polymorphisms on hepatic CBR3 mRNA expression.
OBJECTIVE
Recent studies suggest that polymorphisms in human carbonyl reductase 3 (CBR3) influence the pharmacodynamics of doxorubicin. First, we sought to identify the promoter of CBR3. Next, we examined whether two CBR3 promoter polymorphisms (CBR3 -725T>C and CBR3 -326T>A) dictate promoter activity and hepatic CBR3 mRNA levels.


METHODS
The promoter activities of CBR3 reporter constructs were investigated in HepG2 and MCF-7 cells. CBR3 mRNA levels were documented in 95 liver samples from white (n = 62) and black (n = 33) donors. Genotype-phenotype correlation analyses were used to determine the impact of the CBR3 -725T>C and CBR3 -326T>A polymorphisms on hepatic CBR3 mRNA levels.


RESULTS
We identified the promoter of human CBR3. Liver samples from black donors showed higher relative CBR3 mRNA levels than samples from whites (CBR3 mRNA(blacks) = 3.0 +/- 3.1 relative fold vs. CBR3 mRNA(whites) = 1.6 +/- 1.5 relative fold, p = 0.021). The variant -725C and -326A alleles did not modify the gene reporter activities of engineered CBR3 promoter constructs. In line, hepatic CBR3 mRNA levels were not associated with CBR3 -725T>C and CBR3 -326T>A genotype status.


CONCLUSIONS
These studies provide the first insights into the regulation and variable hepatic expression of polymorphic CBR3.
Zhang
Jianping
J
Department of Pharmaceutical Sciences, The State University of New York at Buffalo, Buffalo, NY 14260-1200, USA.
Blanco
Javier G
JG
D000429:Alcohol Oxidoreductases / Q000235:genetics*; D001483:Base Sequence; D045744:Cell Line, Tumor; D017931:DNA Primers; D017930:Genes, Reporter; D006801:Humans; D008099:Liver / Q000378:metabolism*; D020641:Polymorphism, Single Nucleotide; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics*
D017931:DNA Primers; D012333:RNA, Messenger; D000429:Alcohol Oxidoreductases; C531130:CBR3 protein, human