Premium
The −1195G allele increases the transcriptional activity of cyclooxygenase‐2 gene (COX‐2) in colon cancer cell lines
Author(s) -
Pereira Carina,
Sousa Hugo,
Silva Joana,
Brandão Carla,
ElguetaKarstegl Claudio,
Farrell Paul J.,
Medeiros Rui,
DinisRibeiro Mário
Publication year - 2014
Publication title -
molecular carcinogenesis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.254
H-Index - 97
eISSN - 1098-2744
pISSN - 0899-1987
DOI - 10.1002/mc.22049
Subject(s) - biology , carcinogenesis , allele , transfection , reporter gene , colorectal cancer , promoter , transcription (linguistics) , gene , cell culture , transcriptional regulation , microbiology and biotechnology , cancer research , luciferase , population , transcription factor , gene expression , genetics , cancer , medicine , linguistics , philosophy , environmental health
Abstract Up‐regulation of cyclooxygenase‐2 ( COX‐2 ) is an early and key event in human colorectal carcinogenesis (CRC). Nevertheless, the molecular mechanisms leading to this over‐expression are largely unknown. We previously reported an association between the −1195G allele and higher predisposition for CRC in a Caucasian population. The biological explanation for the involvement of this polymorphism in CRC remains elusive. We aimed to functionally characterize the influence of the −1195A>G promoter region polymorphism on COX‐2 transcription activity in colon cancer cell lines. Luciferase reporter assays were performed to assess whether the −1195A/G alleles influenced COX‐2 transcription. The COX‐2 promoter's region containing either the −1195A or −1195G alleles was cloned into pGL3 ‐basic reporter vector. The reporter vectors were transiently co‐transfected with the pGL4.73 control plasmid to HCT‐116 and HCA‐7 colon cancer cell lines. The levels of reporter gene expression driven by the −1195G allele‐containing COX‐2 promoter were significantly higher in both colon cancer cell lines. A 2.2‐fold increase in promoter activity was observed in the HCT‐116 cell line ( P < 0.001), and this over‐expression was even more noticeable in the HCA‐7 COX‐2 expressing cell line with a threefold higher transcriptional activity ( P = 0.001). The −1195G allele appeared to enhance COX‐2 transcription, providing a molecular basis underlying the increased susceptibility for CRC and potentially a new mechanism for COX‐2 overexpression. © 2013 Wiley Periodicals, Inc.