Novel snail1 target proteins in human colon cancer identified by proteomic analysis.
BACKGROUND
The transcription factor Snail1 induces epithelial-to-mesenchymal transition (EMT), a process responsible for the acquisition of invasiveness during tumorigenesis. Several transcriptomic studies have reported Snail1-regulated genes in different cell types, many of them involved in cell adhesion. However, only a few studies have used proteomics as a tool for the characterization of proteins mediating EMT.


RESULTS
We identified by proteomic analysis using 2D-DIGE electrophoresis combined with MALDI-TOF-TOF and ESI-linear ion trap mass spectrometry a number of proteins with variable functions whose expression is modulated by Snail1 in SW480-ADH human colon cancer cells. Validation was performed by Western blot and immunofluorescence analyses. Snail1 repressed several members of the 14-3-3 family of phosphoserine/phosphothreonine binding proteins and also the expression of the Proliferation-associated protein 2G4 (PA2G4) that was mainly localized at the nuclear Cajal bodies. In contrast, the expression of two proteins involved in RNA processing, the Cleavage and polyadenylation specificity factor subunit 6 (CPSF6) and the Splicing factor proline/glutamine-rich (SFPQ), was higher in Snail1-expressing cells than in controls. The regulation of 14-3-3epsilon, 14-3-3tau, 14-3-3zeta and PA2G4 by Snail1 was reproduced in HT29 colon cancer cells. In addition, we found an inverse correlation between 14-3-3sigma and Snail1 expression in human colorectal tumors.


CONCLUSIONS
We have identified a set of novel Snail1 target proteins in colon cancer that expand the cellular processes affected by Snail1 and thus its relevance for cell function and phenotype.
Larriba
María Jesús
MJ
Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Madrid, Spain. mjlarriba@iib.uam.es
Casado-Vela
Juan
J
Pendás-Franco
Natalia
N
Peña
Raúl
R
García de Herreros
Antonio
A
Berciano
María Teresa
MT
Lafarga
Miguel
M
Casal
J Ignacio
JI
Muñoz
Alberto
A
D003110:Colonic Neoplasms / Q000737:chemistry*; D015180:Electrophoresis, Gel, Two-Dimensional; D004847:Epithelial Cells; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D059630:Mesenchymal Stem Cells; D009363:Neoplasm Proteins / Q000032:analysis*; D040901:Proteomics / Q000379:methods*; D012097:Repressor Proteins; D000071250:Snail Family Transcription Factors; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014157:Transcription Factors / Q000032:analysis* / Q000502:physiology
D009363:Neoplasm Proteins; D012097:Repressor Proteins; C000604407:SNAI1 protein, human; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors