title: Functional proteomics of resveratrol-induced colon cancer cell apoptosis: caspase-6-mediated cleavage of lamin A is a major signaling loop.
abstract: The study investigated the molecular basis of resveratrol (RSV)-evoked apoptosis in four (Bax+/-, Bax-/-, p53+/+, and p53-/-) HCT116 colon cancer cell lines. RSV induced apoptosis in all the cells in a dose-dependent manner; however, Bax+/- and p53+/+ cells were more susceptible than their knockout counterparts (Bax-/- and p53-/-, respectively). Using Bax+/- cells as a model, proteomic analysis revealed four RSV-responsive events: fragmentation of lamin A/C protein; increase in concentration of a more basic isoelectric variant of the ribosomal protein P0; and decrease in concentration of dUTPase as well as stathmin 1. Lamin A cleavage in response to RSV treatment was confirmed using Western blot analysis. Caspase-6 was activated, which was evidenced by cleavage and accumulation in active form of caspase-6 as well as upregulation of the protease activity. RSV-elicited lamin A cleavage and apoptosis were entirely abrogated by the peptide inhibitors of caspase-6. Likewise, partial knockdown of caspase-6 expression using small interfering RNA resulted in significant inhibition of RSV-elicited lamin A cleavage and apoptosis. Furthermore, the lower apoptosis sensitivity of the knockout cells (Bax-/- and p53-/-) correlated with the relatively reduced processing of caspase-6 and lamin A cleavage. Taken together, these data highlight the critical role of caspase-6 and its cleavage of lamin A in apoptotic signaling triggered by RSV in the colon carcinoma cells, which can be activated in the absence of Bax or p53.
authors.affiliation: National University Medical Institute, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
authors.forename: Shao Chin
authors.initials: SC
authors.lastname: Lee
authors.forename: Jason
authors.initials: J
authors.lastname: Chan
authors.forename: Marie-Veronique
authors.initials: MV
authors.lastname: Clement
authors.forename: Shazib
authors.initials: S
authors.lastname: Pervaiz
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D017209:Apoptosis; D053178:Caspase 6; D020169:Caspases / Q000378:metabolism*; D045744:Cell Line, Tumor; D003110:Colonic Neoplasms / Q000188:drug therapy* / Q000473:pathology*; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D034904:Lamin Type A / Q000737:chemistry*; D040901:Proteomics / Q000379:methods*; D000077185:Resveratrol; D015398:Signal Transduction; D013267:Stilbenes / Q000494:pharmacology*; D019076:Transgenes; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D051028:bcl-2-Associated X Protein / Q000378:metabolism
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D034904:Lamin Type A; D013267:Stilbenes; D016159:Tumor Suppressor Protein p53; D051028:bcl-2-Associated X Protein; C505514:CASP6 protein, human; D053178:Caspase 6; D020169:Caspases; D000077185:Resveratrol