Slonchak A. Cell-specific particularities of the human glutathione S-transferase gene transcription regulation

The object - regulation of the human glutathione S-transferase P1 (GSTP1) gene transcription. The aim of the work was to uncover the role of cis- and trans- acting factors in cell- specific regulation of GSTP1 transcriptional activity. Methods - quantitative RT-PCR, semi-quantitative western-blotting, DNA bisulfite treatment, polymerase chain reaction, molecular cloning, cell culture and transfection, luciferase assay, electrophoretic mobility shift assay. Results and novelty - the role of cis- and trans- acting factors in cell-specific regulation of GSTP1 transcription in breast cells Hbl-100, melanoma cells Me45, choriocarcinoma cells BeWo and normal placental tissue was identified in this work. It was shown that ARE and NF-kB sites of GSTP1 gene promoter act as positive regulatory elements, but CRE and NF-kB-like as negative. The differences in the patterns of transcription factors interacting with GSTP1 promoter in different cell types possessing distinct levels of GSTP1 expression were identified for the first time. It was shown that transcriptional repression of GSTP1 in examined cells occurs due to transcription factors and can be fixed by promoter methylation. The negative regulatory role of CRE was shown for the first time. We identified for the first time that estrogen receptor (ER) regulates GSTP1 transcription interacting with positive regulatory element ARE in complex with unknown protein and with negative regulatory element CRE in complex with Fos or Jun/Fos. Based on these results we proposed a model which explains the interaction of the same transcription factor with positive and negative regulatory elements of one promoter in context of contemporary view on structure and function of enchansosome. Obtained results provide the evidence that GSTP1 gene transcription is cell-specifically regulated by ER and NF-kB what allows to consider these factors as potential targets for chemopreventive drugs.