Mucosal immune environment in colonic carcinogenesis: CD80 expression is associated to oxidative DNA damage and TLR4-NFκB signalling.
BACKGROUND
CD80 has been thought to play an active role in immunosurveillance as it has been found to be up-regulated in ulcerative colitis (UC) patients with dysplasia. The aim of the present study was to analyse early events in UC-related and non-inflammatory carcinogenesis with reference to CD80 expression to clarify what stimuli are involved in its up-regulation in these patients.


METHODS
Sixty-two patients affected with UC, UC with dysplasia, UC and cancer, colonic adenoma, or colonic cancer and 11 healthy subjects were enroled in our study. Tissue samples were taken from surgical specimens during colonic resection or during colonoscopy. Mucosal mRNA expression of Toll-like receptor-4 (TLR4) and nuclear factor-kappaB (NF-κB) was quantified with Real Time RT-PCR. TLR4, β-catenin and p53 expressions were analysed by immunohistochemistry. Mucosal levels of activated NF-κB were measured with immunometric assays while 8-Hydroxydeoxyguanosine (8-OHdG) levels were quantified by high-performance liquid chromatography with electrochemical detection (HPLC-ED). Non-parametric tests were used for statistical analysis.


RESULTS
8-OHdG mucosal levels were higher in the patients with UC + dysplasia with respect to those in the patients with UC only (p=0.03). CD80 mRNA mucosal levels were directly correlated with 8-OHdG mucosal levels (τ=0.26, p=0.04), TLR4 protein expression (τ=0.45, p<0.01) and NF-κB mRNA expression and activity (τ=0.24, p=0.02; τ=0.34, p=0.02, respectively). CD80 protein expression, instead, was directly correlated with 8-OHdG mucosal levels (τ=0.19, p=0.05) and inversely correlated with TLR4 mRNA expression (τ=-0.25, p=0.03).


CONCLUSIONS
Oxidative DNA damage peaked in UC-related dysplasia and was found to be directly correlated to CD80 expression. The direct correlation between TLR4 protein expression and CD80 mRNA and the indirect correlation between CD80 protein and TLR4 mRNA expressions give substance to the hypothesis that they play a role in immunosurveillance. No significant correlations between CD80 expression and p53 and β-catenin accumulation during oncogenesis were, instead, observed.
Oncological Surgery Unit, Veneto Institute of Oncology (IOV-IRCCS), Padova, Italy. marcoscarpa73@yahoo.it
Marco
M
Scarpa
Romilda
R
Cardin
Marina
M
Bortolami
Andromachi
A
Kotsafti
Maria Cristina
MC
Scarpa
Anna
A
Pozza
Giorgia
G
Maran
Marika
M
Picciocchi
Cesare
C
Ruffolo
Renata
R
D'Incà
Giacomo C
GC
Sturniolo
Ignazio
I
Castagliuolo
Carlo
C
Castoro
Imerio
I
Angriman
D000230:Adenocarcinoma / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D000236:Adenoma / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D000328:Adult; D018122:B7-1 Antigen / Q000096:biosynthesis*; D002471:Cell Transformation, Neoplastic / Q000276:immunology* / Q000473:pathology; D003093:Colitis, Ulcerative / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D003110:Colonic Neoplasms / Q000276:immunology* / Q000378:metabolism / Q000473:pathology*; D004249:DNA Damage / Q000502:physiology; D005260:Female; D006801:Humans; D007413:Intestinal Mucosa / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D008297:Male; D008875:Middle Aged; D016328:NF-kappa B / Q000276:immunology / Q000378:metabolism; D018384:Oxidative Stress / Q000502:physiology; D011230:Precancerous Conditions / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000502:physiology; D051197:Toll-Like Receptor 4 / Q000276:immunology / Q000378:metabolism
D018122:B7-1 Antigen; D016328:NF-kappa B; C495345:TLR4 protein, human; D051197:Toll-Like Receptor 4