title: Protein cross-talk in CD133+ colon cancer cells indicates activation of the Wnt pathway and upregulation of SRp20 that is potentially involved in tumorigenicity.
abstract: The cancer stem cell (CSC) theory represents a breakthrough in cancer research. We characterized the protein pattern of CSCs to identify specific intracellular pathways in this subpopulation of tumor cells. We studied colon CSCs using two different colon cancer cell lines: CaCo-2 and HCT-116. Putative CSCs were separated from non-CSCs by flow cytometry using CD133 as stemness marker. Total protein extracts of CD133+ cells were then compared to protein extracts of CD133- cells by 2D DIGE. The protein spots differentially expressed in the two subpopulations of cells were analyzed by mass spectrometry. Bioinformatics analysis of the identified proteins indicated alteration of two main processes: energy metabolism and the Wnt pathway. Interestingly, we observed upregulation of the splicing factor SRp20, a newly identified target gene of the Wnt/β-catenin pathway, and we demonstrated a direct cause-effect relationship between Wnt pathway activation and the increased SRp20 expression. Our results also show that SRp20 influences cell proliferation, which suggests it plays a role in the tumorigenicity of CD133+ cells. In conclusion, activation of the Wnt pathway in CD133+ cells and upregulation of SRp20, which is implicated in tumorigenesis, raises the possibility of a sequential series of molecular events occurring in connection with this process.
authors.affiliation: CEINGE, Biotecnologie Avanzate scarl, Naples, Italy.
authors.forename: Claudia
authors.initials: C
authors.lastname: Corbo
authors.forename: Stefania
authors.initials: S
authors.lastname: Orrù
authors.forename: Marica
authors.initials: M
authors.lastname: Gemei
authors.forename: Rosa Di
authors.initials: RD
authors.lastname: Noto
authors.forename: Peppino
authors.initials: P
authors.lastname: Mirabelli
authors.forename: Esther
authors.initials: E
authors.lastname: Imperlini
authors.forename: Margherita
authors.initials: M
authors.lastname: Ruoppolo
authors.forename: Luigi Del
authors.initials: LD
authors.lastname: Vecchio
authors.forename: Francesco
authors.initials: F
authors.lastname: Salvatore
mesh_terms: D000071916:AC133 Antigen; D015703:Antigens, CD / Q000737:chemistry / Q000378:metabolism*; D015153:Blotting, Western; D018938:Caco-2 Cells; D048708:Cell Growth Processes / Q000235:genetics; D003110:Colonic Neoplasms / Q000737:chemistry / Q000378:metabolism* / Q000473:pathology; D015180:Electrophoresis, Gel, Two-Dimensional; D005434:Flow Cytometry; D020868:Gene Silencing; D006023:Glycoproteins / Q000737:chemistry / Q000378:metabolism*; D045325:HCT116 Cells; D006801:Humans; D014411:Neoplastic Stem Cells / Q000737:chemistry / Q000378:metabolism / Q000473:pathology; D010455:Peptides / Q000737:chemistry / Q000378:metabolism*; D034741:RNA, Small Interfering; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D015203:Reproducibility of Results; D000068103:Serine-Arginine Splicing Factors; D015854:Up-Regulation; D060449:Wnt Signaling Pathway / Q000502:physiology*
chemical_list: D000071916:AC133 Antigen; D015703:Antigens, CD; D006023:Glycoproteins; C000606023:PROM1 protein, human; D010455:Peptides; D034741:RNA, Small Interfering; D016601:RNA-Binding Proteins; C491388:SRSF3 protein, human; D000068103:Serine-Arginine Splicing Factors