Post on 05-Jan-2016
O papel dos C/EBPs no estômago. Diferenciação vs proliferação.
José Carlos Machado, Porto, Portugal
Aneuploidy# 3p, 7q, 13q (LOH)# 6q (LOH)# 1q, 5q, 17p (LOH)RAS (overexpression/mutation)ERBB-2 (amplification)TPR-MET (rearrangement)c-MET (6.0 Kb mARN)
p 53 (LOH, mutation)APC (LOH, mutation)DCC (LOH)EGF (overexpression)TGF-a (overexpression)TFF1 (loss of expression)
MSI (Microsatellite Instability)
S-Tn, T, S-TCDw75, S-LexLaminin, collagen IVu-PA, Cat-D NM 23 (loss)CD 44 (variants)
Diploidy# 3p, 7q, 13q (LOH)# 6q (LOH)
c-MET (6.0 Kb mRNA)
p 53 (LOH, mutation)
TGF-ß (overexpression)
K-SAM (amplification)
E-cadherin (loss/mutation)
S-Tn, T, S-TCDw75, S-Lex
NM 23 (loss)CD 44 (variants)
Intestinal carcinoma Diffuse carcinoma
Gastric gland
TFF1 expression in gastric carcinogenesis.
Machado JC et al. J Pathol 190: 437, 2000
C/EBPbeta
Ki67
Ki67 and C/EBP-β in normal gastric mucosa
Intestinal metaplasia Gastric dysplasia
C/EBPbeta expression
Intestinal atypical diffuseIntestinal Solid Diffuse
C/EBPbeta expression
C/EBP-β staining overlaps Ki67
C/EBP Ki67
C/EBPbeta mutation in a primary gastric carcinoma
Pro58Ala
Wild-type
Basic leucine zipper DNA-binding protein
C/EBP-β or NFIL6
TFF1 knockout mice developed adenomas and gastric cancer
Lefebvre O et al. Science 274: 259, 1996
C/EBPbeta and COX-2 co-expression in gastric carcinoma
COX2 C/EBPbeta Double IHC
C/EBP-β expression in GC cell lines
Luciferase assay showing the effect of C/EBPbeta transfection on COX-2 promoter activity
C/EBPα is expressed in gastric differentiated cells and co-localizes with TFF1
C/EBPα is under expressed in 34.6% of intestinal and atypical but not diffuse type carcinomas
non-neoplastic intestinal diffuse
A C/EBPα expression vector inhibits AGS cell proliferation
BRDU
Dapi
média
0
5
10
15
20
25
30
35
40
45
Mock 42KD
isoformas
% p
roli
fera
ção
média
C/EBPα modulates cell cycle proteins and is capable of up-regulating TFF1 expression
EGFRHER2/neu
IL6R/GP130
TGFBR
STAT3
Pi3K
Ras
SHP2
GSK3beta ERK
C/EBPbeta
Smad3
phosphorylationin
activ
atio
n
AKT
TFF1COX2
Candidate signalling pathways
C/EBPβ
C/EBPα
ciclinD1
p-ERK1/2
p-p38
tubulin
C/EBP stimulation with IL1B leads to phosphoeilation of ERK1/2 and p38
0 SB PD IL1b
IL1b+SB-p38
IL1b+PD
ERK
phospho-p38C/EBPβ Ki67
C/EBP co-localizes with phopho-p38
Conclusions C/EBPbeta is expressed in proliferative cells of the normal gastric
mucosa, and is overexpressed in intestinal metaplasia, dysplasia, and GC of the intestinal and atypical subtypes;
COX-2 is co-expressed with C/EBPbeta and can be regulated by this transcription factor;
C/EBPbeta may both be a marker of neoplastic transformation and play an active role in gastric tumourigenesis by regulating COX-2 expression;
C/EBPα is expressed in gastric foveolar differentiated cells and under-expressed in intestinal and atypical type tumours;
C/EBPα colocalizes with and up-regulates TFF1, and inhibits cell proliferation by changing the expression of cell cycle proteins in vitro.