title: Quantitative and temporal proteome analysis of butyrate-treated colorectal cancer cells.
abstract: Colorectal cancer is one of the most common cancers in developed countries, and its incidence is negatively associated with high dietary fiber intake. Butyrate, a short-chain fatty acid fermentation by-product of fiber induces cell maturation with the promotion of growth arrest, differentiation, and/or apoptosis of cancer cells. The stimulation of cell maturation by butyrate in colonic cancer cells follows a temporal progression from the early phase of growth arrest to the activation of apoptotic cascades. Previously we performed two-dimensional DIGE to identify differentially expressed proteins induced by 24-h butyrate treatment of HCT-116 colorectal cancer cells. Herein we used quantitative proteomics approaches using iTRAQ (isobaric tags for relative and absolute quantitation), a stable isotope labeling methodology that enables multiplexing of four samples, for a temporal study of HCT-116 cells treated with butyrate. In addition, cleavable ICAT, which selectively tags cysteine-containing proteins, was also used, and the results complemented those obtained from the iTRAQ strategy. Selected protein targets were validated by real time PCR and Western blotting. A model is proposed to illustrate our findings from this temporal analysis of the butyrate-responsive proteome that uncovered several integrated cellular processes and pathways involved in growth arrest, apoptosis, and metastasis. These signature clusters of butyrate-regulated pathways are potential targets for novel chemopreventive and therapeutic drugs for treatment of colorectal cancer.
authors.affiliation: Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, 10 Kent Ridge Crescent, Singapore 117597, Singapore.
authors.forename: Hwee Tong
authors.initials: HT
authors.lastname: Tan
authors.forename: Sandra
authors.initials: S
authors.lastname: Tan
authors.forename: Qingsong
authors.initials: Q
authors.lastname: Lin
authors.forename: Teck Kwang
authors.initials: TK
authors.lastname: Lim
authors.forename: Choy Leong
authors.initials: CL
authors.lastname: Hew
authors.forename: Maxey C M
authors.initials: MC
authors.lastname: Chung
mesh_terms: D017209:Apoptosis; D002087:Butyrates / Q000494:pharmacology*; D002453:Cell Cycle; D045744:Cell Line, Tumor; D015179:Colorectal Neoplasms / Q000188:drug therapy*; D003545:Cysteine / Q000737:chemistry; D005189:False Positive Reactions; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D013058:Mass Spectrometry / Q000379:methods; D008954:Models, Biological; D010455:Peptides / Q000737:chemistry; D040901:Proteomics / Q000379:methods*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors
chemical_list: D002087:Butyrates; D010455:Peptides; D003545:Cysteine