title: Resveratrol-induced apoptosis is mediated by early growth response-1, Krüppel-like factor 4, and activating transcription factor 3.
abstract: Resveratrol, a dietary phytoalexin readily available in the diet, is reported to possess antitumorigenic properties in several cancers, including colorectal. However, the underlying mechanism(s) involved is not completely understood. In the present study, we investigated the effect of resveratrol treatment on gene modulation in human colorectal cancer cells and identified activating transcription factor 3 (ATF3) as the most highly induced gene after treatment. We confirmed that resveratrol upregulates ATF3 expression, both at the mRNA and protein level, and showed resveratrol involvement in ATF3 transcriptional regulation. Analysis of the ATF3 promoter revealed the importance of early growth response-1 (Egr-1; located at -245 to -236) and Krüppel-like factor 4 (KLF4; located at -178 to -174) putative binding sites in resveratrol-mediated ATF3 transactivation. Specificity of these sites to the Egr-1 and KLF4 protein was confirmed by electrophoretic mobility shift and chromatin immunoprecipitation assays. Resveratrol increased Egr-1 and KLF4 expression, which preceded ATF3 expression, and further suggests Egr-1 and KLF4 involvement in resveratrol-mediated activity. We provide evidence for Egr-1 and KLF4 interaction in the presence of resveratrol, which may facilitate ATF3 transcriptional regulation by this compound. Furthermore, we demonstrate that induction of apoptosis by resveratrol is mediated, in part, by increased ATF3 expression. Taken together, these results provide a novel mechanism by which resveratrol induces ATF3 expression and represent an additional explanation of how resveratrol exerts its antitumorigenic effects in human colorectal cancer cells.
authors.affiliation: Laboratory of Environmental Carcinogenesis, Department of Pathobiology, College of Veterinary Medicine, University of Tennessee, Knoxville, Tennesse 37996, USA.
authors.forename: Nichelle C
authors.initials: NC
authors.lastname: Whitlock
authors.forename: Jae Hoon
authors.initials: JH
authors.lastname: Bahn
authors.forename: Seong-Ho
authors.initials: SH
authors.lastname: Lee
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Eling
authors.forename: Seung Joon
authors.initials: SJ
authors.lastname: Baek
mesh_terms: D051700:Activating Transcription Factor 3 / Q000378:metabolism*; D016588:Anticarcinogenic Agents / Q000627:therapeutic use*; D017209:Apoptosis / Q000187:drug effects*; D001483:Base Sequence; D001665:Binding Sites; D015153:Blotting, Western; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D047369:Chromatin Immunoprecipitation; D015179:Colorectal Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D051766:Early Growth Response Protein 1 / Q000235:genetics* / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D006801:Humans; D007124:Immunoenzyme Techniques; D047468:Immunoprecipitation; D000090062:Kruppel-Like Factor 4; D051741:Kruppel-Like Transcription Factors / Q000235:genetics* / Q000378:metabolism; D008156:Luciferases / Q000378:metabolism; D008969:Molecular Sequence Data; D010766:Phosphorylation / Q000187:drug effects; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D012333:RNA, Messenger / Q000235:genetics; D000077185:Resveratrol; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013267:Stilbenes / Q000627:therapeutic use*; D015533:Transcriptional Activation
chemical_list: C490449:ATF3 protein, human; D051700:Activating Transcription Factor 3; D016588:Anticarcinogenic Agents; C497325:EGR1 protein, human; D051766:Early Growth Response Protein 1; C000715467:KLF4 protein, human; D000090062:Kruppel-Like Factor 4; D051741:Kruppel-Like Transcription Factors; D012333:RNA, Messenger; D013267:Stilbenes; D008156:Luciferases; D000077185:Resveratrol