title: SNAI2 modulates colorectal cancer 5-fluorouracil sensitivity through miR145 repression.
abstract: Epithelial-to-mesenchymal transition (EMT) has been associated with poor treatment outcomes in various malignancies and is inversely associated with miRNA145 expression. Therefore, we hypothesized that SNAI2 (Slug) may mediate 5-fluorouracil (5FU) chemotherapy resistance through inhibition of miR145 in colorectal cancer and thus represents a novel therapeutic target to enhance current colorectal cancer treatment strategies. Compared with parental DLD1 colon cancer cells, 5FU-resistant (5FUr) DLD1 cells demonstrated features of EMT, including >2-fold enhanced invasion (P < 0.001) and migration, suppressed E-cadherin expression, and 2-fold increased SNAI2 expression. DLD1 and HCT116 cells with stable expression of SNAI2 (DLD1/SNAI2; HCT116/SNAI2) also demonstrated EMT features such as the decreased E-cadherin as well as significantly decreased miR145 expression, as compared with control empty vector cells. On the basis of an miR145 luciferase promoter assay, we demonstrated that SNAI2 repressed activity of the miR145 promoter in the DLD1 and HCT116 cells. In addition, the ectopic expressing SNAI2 cell lines demonstrated decreased 5FU sensitivity, and, conversely, miR145 replacement significantly enhanced 5FU sensitivity. In the parental SW620 colon cancer cell line with high SNAI2 and low miR145 levels, inhibition of SNAI2 directly with short hairpin sequence for SNAI2 and miR145 replacement therapy both decreased vimentin expression and increased in vitro 5FU sensitivity. In pretreatment rectal cancer patient biopsy samples, low miR145 expression levels correlated with poor response to neoadjuvant 5FU-based chemoradiation. These results suggested that the SNAI2:miR145 pathway may represent a novel clinical therapeutic target in colorectal cancer and may serve as a response predictor to chemoradiation therapy.
authors.affiliation: Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, South Carolina. Hollings Cancer Center, Medical University of South Carolina, Charleston, South Carolina. campe@musc.edu findlay@musc.edu.
authors.forename: Victoria J
authors.initials: VJ
authors.lastname: Findlay
authors.affiliation: Department of Surgery, Medical University of South Carolina, Charleston, South Carolina.
authors.forename: Cindy
authors.initials: C
authors.lastname: Wang
authors.affiliation: Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, South Carolina.
authors.forename: Lourdes M
authors.initials: LM
authors.lastname: Nogueira
authors.affiliation: Department of Surgery, Medical University of South Carolina, Charleston, South Carolina.
authors.forename: Katie
authors.initials: K
authors.lastname: Hurst
authors.affiliation: Department of Surgery, Medical University of South Carolina, Charleston, South Carolina.
authors.forename: Daniel
authors.initials: D
authors.lastname: Quirk
authors.affiliation: Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, South Carolina. Hollings Cancer Center, Medical University of South Carolina, Charleston, South Carolina.
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Ethier
authors.affiliation: Hollings Cancer Center, Medical University of South Carolina, Charleston, South Carolina. Department of Surgery, Medical University of South Carolina, Charleston, South Carolina. Ralph H. Johnson VA Medical Center, Charleston, South Carolina.
authors.forename: Kevin F
authors.initials: KF
authors.lastname: Staveley O'Carroll
authors.affiliation: Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, South Carolina. Hollings Cancer Center, Medical University of South Carolina, Charleston, South Carolina. Department of Biochemistry Molecular Biology, Medical University of South Carolina, Charleston, South Carolina.
authors.forename: Dennis K
authors.initials: DK
authors.lastname: Watson
authors.affiliation: Hollings Cancer Center, Medical University of South Carolina, Charleston, South Carolina. Department of Surgery, Medical University of South Carolina, Charleston, South Carolina. Ralph H. Johnson VA Medical Center, Charleston, South Carolina. campe@musc.edu findlay@musc.edu.
authors.forename: E Ramsay
authors.initials: ER
authors.lastname: Camp
mesh_terms: D045744:Cell Line, Tumor; D015179:Colorectal Neoplasms / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism / Q000628:therapy*; D019008:Drug Resistance, Neoplasm; D058750:Epithelial-Mesenchymal Transition / Q000187:drug effects / Q000235:genetics; D005472:Fluorouracil / Q000494:pharmacology*; D045325:HCT116 Cells; D019073:HT29 Cells; D006801:Humans; D035683:MicroRNAs / Q000096:biosynthesis* / Q000235:genetics; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000235:genetics*; D014162:Transfection
chemical_list: C541010:MIRN145 microRNA, human; D035683:MicroRNAs; C000604407:SNAI1 protein, human; C000604408:SNAI2 protein, human; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors; D005472:Fluorouracil