Reversal of gene expression changes in the colorectal normal-adenoma pathway by NS398 selective COX2 inhibitor.

BACKGROUND AND AIMS: Treatment of colorectal adenomas with selective cyclooxygenase-2 inhibitors can contribute to the chemoprevention of colorectal cancer (CRC), but the molecular background of their effect is not fully understood. We analysed the gene expression modulatory effect of N-(2-cyclohexyloxy-4-nitrophenyl)-methanesulfonamide (NS398) on HT29 cells to be correlated with expression data gained from biopsy samples. METHODS: HT29 colon adenocarcinoma cells were treated with NS398, and global mRNA expression was analysed on HGU133Plus2.0 microarrays. Discriminatory transcripts between normal and adenoma and between adenoma and CRC biopsy samples were identified using HGU133Plus2.0 microarrays. The results were validated using RT-PCR and immunohistochemistry. RESULTS: Between normal and adenoma samples, 20 classifiers were identified, including overexpressed cadherin 3, KIAA1199, and downregulated peptide YY, glucagon, claudin 8. Seventeen of them changed in a reverse manner in HT29 cells under NS398 treatment, 14 (including upregulated claudin 8, peptide YY, and downregulated cadherin 3, KIAA1199) at a significance of P<0.05. Normal and CRC could be distinguished using 38 genes, the expression of 12 of them was changed in a reverse manner under NS398 treatment. CONCLUSION: NS398 has a reversal effect on the expression of several genes that altered in colorectal adenoma-carcinoma sequence. NS398 more efficiently inverted the expression changes seen in the normal-adenoma than in the normal-carcinoma transition.

The RR genotype of codon 72 of p53 gene reduces the development of intestinal metaplasia.

BACKGROUND AND AIMS: Mutations of p53 gene can contribute to the development of gastric cancer. Our aims were to evaluate the premalignant gastric intestinal metaplasia-related p53 alterations, using and comparing capillary sequencing and p53 resequencing chip in gastric biopsy and peripheral blood samples. Furthermore we examined the effect of p53 polymorphism on the protein expression level. PATIENTS AND METHODS: Deoxyribonucleic acid was extracted from antral gastric biopsy samples of 50 intestinal metaplasia patients (27 Helicobacter pylori positive, 23 H. pylori negative) and 51 controls (all H. pylori negative). Exon 4 of p53 gene was examined by capillary sequencing (CS). From 7 intestinal metaplasia patients extra deoxyribonucleic acid samples were extracted from blood and from the corpus and from the antrum of the stomach and 5 additional exons were examined by CS and 10 with GeneChip p53 Assay (Affymetrix). In 19 patients p53 immunohistochemistry was performed. RESULTS: RR genotype on codon 72 was found to significantly (p=0.0087) reduce the chance of intestinal metaplasia in H. pylori positive patients as compared to the normal controls. The p53 alterations were identical in antral, corpus and blood samples. The p53 protein expression was in significant correlation with the genetic alterations. CS and chip method-based sequencing results were not in correlation. CONCLUSIONS: According to our results RR genotype decreases the incidence of IM. The genetic background is reflected in the expression of p53 protein. Chip method-based deoxyribonucleic acid sequence data need careful confirmation.