Multistage gene expression profiling in a differentially susceptible mouse colon cancer model

Area of Science:

• Molecular Biology
• Genomics
• Cancer Research

Background:

• Azoxymethane (AOM) is a DNA alkylating agent that induces colon tumor formation.
• Differential susceptibility to AOM is observed between A/J (sensitive) and AKR/J (resistant) mouse strains.
• The molecular mechanisms underlying AOM-induced colon tumorigenesis and strain-specific responses remain largely unknown.

Purpose of the Study:

• To investigate time-related gene expression changes in the colons of A/J and AKR/J mice following AOM exposure.
• To identify molecular pathways and genetic alterations contributing to differential susceptibility and tumor progression.

Main Methods:

• A cDNA microarray approach was employed using 4608 mouse cDNA clones.
• Mice were treated with AOM or saline (vehicle control) and RNA was isolated at 1, 4, and 24 weeks post-exposure.
• Gene expression data were analyzed using GLEAMS 3.0 software, with significant variations defined as twofold changes. Clustering analysis was performed using an adaptive centroid algorithm (ACA).

Main Results:

• Out of 4608 genes analyzed, 118 clustered into 11 significant groups based on expression patterns.
• Distinct and similar expression patterns were observed between A/J and AKR/J mice post-AOM treatment.
• Nine clusters showing divergent responses between strains and potential roles in tumorigenesis were selected for further analysis.

Conclusions:

• AOM treatment induces time- and strain-specific genetic alterations in mouse colon tissue.
• These findings provide insights into the molecular mechanisms of colon tumorigenesis and differential cancer susceptibility.
• The identified gene expression patterns may serve as biomarkers for colon cancer progression and therapeutic targets.