Functional analysis of aryl hydrocarbon receptor polymorphisms in pituitary adenomas in the presence of 2,3,7,8-Tetrachlorodibenzo-p-dioxin

Abstract

Introduction: The molecular pathogenesis of the most prevalent intracranial neoplasm, pituitary adenomas (PA) is largely unknown. The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor that regulates expression of various genes that mediate cellular response to xenobiotics. The exact functional role of two AHR single nucleotide polymorphisms (SNPs); Arginine554Lysine (Arg554Lys) and Valine570Isoleucine (Val570Ile) has not yet been established. However, studies suggest that these variants might increase risk of developing PA.

Methods: Using site-directed mutagenesis, AHRexpressing vectors containing both SNPs were generated. The rat somatotroph cell-line GH3 was transfected with the wildtype AHR (wtAHR) and the AHR variants using magnetofaction and treated with the activating ligand 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD). The luciferase reporter assays and real-time PCR were used to quantify the AHR-transcriptional activity. Genotyping of the Arg554Lys was performed on PA patients and neonatal controls using allele-specific PCR.