title: Sulfotransferase 1A1 (SULT1A1) gene expression is regulated by members of the NFI transcription factors in human breast cancer cells.
abstract: BACKGROUND
  Sulfotransferase 1A1 (SULT1A1) gene expression is tissue specific, with little to no expression in normal breast epithelia. Expression in breast tumors has been documented, but the transcriptional regulation of SULT1A1 in human breast tissue is poorly understood. We identified Nuclear Factor I (NFI) as a transcription factor family involved in the regulation of SULT1A1 expression.
  
  
  METHODS
  Transcription Factor Activation Profiling Plate Array assay was used to identify the possible transcription factors that regulate the gene expression of SULT1A1in normal breast MCF-10A cells and breast cancer ZR-75-1 cells. Expression levels of NFI-C and SULT1A1 were determined by real-time RT-PCR using total RNA isolated from 84 human liver samples. Expression levels of SULT1A1, NFI-A, NFI-B, NFI-C, and NFI-X were also determined in different human breast cancer cell lines (MCF-7, T-47D, ZR-75-1, and MDA-MB-231), in the transformed human epithelial cell line MCF-10A, and in ZR-75-1 cells that were transfected with siRNAs directed against NFI-A, NFI-B, NFI-C, or NFI-X for 48 h. The copy numbers of SULT1A1 in cell lines ZR-75-1, MCF-7, T-47D, MDA-MB-231, and MCF-10A were determined using a pre-designed Custom Plus TaqMan® Copy Number kit from Life Technologies.
  
  
  RESULTS
  In normal human liver samples, SULT1A1 mRNA level was positively associated with NFI-C. In different human breast cancer and normal epithelial cell lines, SULT1A1 expression was positively correlated with NFI-B and NFI-C. SULT1A1 expression was decreased 41% and 61% in ZR-75-1 cells treated with siRNAs against NFI-A and NFI-C respectively. SULT1A1 gene expression was higher in cells containing more than one SULT1A1 copy numbers.
  
  
  CONCLUSIONS
  Our data suggests that SULT1A1 expression is regulated by NFI, as well as SULT1A1 copy number variation in human breast cancer cell lines. These data provide a mechanistic basis for the differential expression of SULT1A1 in different tissues and different physiological states of disease.
authors.forename: Aiwei
authors.initials: A
authors.lastname: Yao-Borengasser
authors.forename: Lora J
authors.initials: LJ
authors.lastname: Rogers
authors.forename: Vineetha K
authors.initials: VK
authors.lastname: Edavana
authors.forename: Rosalind B
authors.initials: RB
authors.lastname: Penney
authors.forename: Xinfeng
authors.initials: X
authors.lastname: Yu
authors.forename: Ishwori B
authors.initials: IB
authors.lastname: Dhakal
authors.forename: Suzanne
authors.initials: S
authors.lastname: Williams
authors.affiliation: Division of Medical Genetics, College of Medicine, University of Arkansas for Medical Sciences, 4301 West Markham St,, Little Rock, AR, 72205, USA. SAKadlubar@uams.edu.
authors.forename: Susan A
authors.initials: SA
authors.lastname: Kadlubar