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

Area of Science:

• Molecular biology
• Cancer research
• Genomics

Background:

• Selective cyclooxygenase-2 inhibitors show promise in colorectal cancer (CRC) chemoprevention.
• The precise molecular mechanisms underlying their effects, particularly on gene expression, require further elucidation.
• Understanding these mechanisms is crucial for developing effective CRC prevention strategies.

Purpose of the Study:

• To investigate the gene expression modulatory effects of N-(2-cyclohexyloxy-4-nitrophenyl)-methanesulfonamide (NS398) on HT29 colon adenocarcinoma cells.
• To correlate these cellular effects with gene expression patterns observed in human colorectal biopsy samples.
• To elucidate the molecular background of how selective cyclooxygenase-2 inhibitors influence the adenoma-carcinoma sequence.

Main Methods:

• Global mRNA expression analysis was performed on HT29 cells treated with NS398 using HGU133Plus2.0 microarrays.
• Discriminatory gene expression profiles were identified between normal, adenoma, and CRC biopsy samples using the same microarray platform.
• Validation of key gene expression changes was conducted using RT-PCR and immunohistochemistry.

Main Results:

• NS398 treatment reversed the expression patterns of several genes identified as classifiers between normal and adenoma tissues.
• Specifically, 14 genes showed significant reversal (P<0.05) with NS398, including upregulation of claudin 8 and peptide YY, and downregulation of cadherin 3 and KIAA1199.
• NS398 also reversed the expression of 12 genes distinguishing normal from CRC, though less efficiently than in the adenoma transition.

Conclusions:

• NS398 demonstrates a gene expression reversal effect on key genes altered during the colorectal adenoma-carcinoma sequence.
• The compound more effectively inverts expression changes associated with the normal-to-adenoma transition compared to the normal-to-carcinoma transition.
• These findings provide insights into the molecular mechanisms of NS398 in colorectal cancer chemoprevention.