Analysis of G/A polymorphism in the androgen response element I of the PSA gene and its interactions with the androgen receptor polymorphisms.

OBJECTIVES: To compare the in vitro functional activity of the prostate-specific antigen (PSA) androgen response element (ARE) I alleles alone or in combination with androgen receptor (AR) polymorphisms and to determine the association of ARE I alleles with serum PSA in men without clinical prostatic disease. Data are conflicting regarding the association of PSA promoter alleles with serum PSA in men.
METHODS: In vitro functional analyses of ARE I and AR polymorphisms were conducted by luciferase reporter assays in LNCaP and PC-3 cells. Associations among serum PSA, ARE I, and AR genotypes were determined by genotyping 109 white and 71 African-American men determined to be free of clinical prostatic disease.
RESULTS: We found no significant difference in the androgen responsiveness of the two alleles when cells were transfected with PSA promoter reporter constructs differing only in the ARE I single nucleotide polymorphism and treated with varying doses of androgen. The response to androgens of the ARE I alleles co-transfected with AR expression vectors of 9, 21, and 29 CAG repeat lengths were identical. No individual or combined effects of the ARE I genotype and the AR genotype on serum PSA were noted.
CONCLUSIONS: Our data indicate that ARE I polymorphisms, alone or in combination with AR polymorphisms, have no functional effect on the activity of the PSA promoter in vitro and in vivo.