Abstract
A connection between colorectal carcinogenesis and inflammation is well known, but the underlying molecular mechanisms have not been elucidated. Chemically induced colitis-associated cancer (CAC) is an outstanding mouse model for studying the link between inflammation and cancer. Additionally, the CAC model is used for examining novel diagnostic, prognostic, and predictive markers for use in clinical practice. Here, a CAC model was established in less than 100 days using azoxymethane (AOM) with dextran sulfate sodium salt (DSS) in BALB/c mice. We examined the mRNA expression profiles of three groups: control untreated mice (K), DSS-induced chronic colitis mice (D), and AOM/DSS-induced CAC (AD) mice. We identified 6301 differentially expressed genes (DEGs) among the three groups, including 93 persistently upregulated genes and 139 persistently downregulated genes. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses revealed that the most persistent DEGs were significantly enriched in metabolic or inflammatory components in the tumor microenvironment. Furthermore, several associated DEGs were identified as potential DEGs by protein-protein interaction (PPI) network analysis. We selected 14 key genes from the DEGs and potential DEGs for further quantitative real-time PCR (qPCR) verification. Six persistently upregulated, 3 persistently downregulated DEGs, and the other 3 genes showed results consistent with the microarray data. We demonstrated the regulation of 12 key genes specifically involved in Wnt signaling, cytokine and cytokine receptor interactions, homeostasis, and tumor-associated metabolism during colitis-associated CRC. Our results suggest that a close relationship between metabolic and inflammatory mediators of the tumor microenvironment is present in CAC.
Highlights
Colorectal cancer (CRC) is a major health problem worldwide
Our analysis indicated that 22 categories were enriched by DAVID and included genes associated with the following functions: cell differentiation; extracellular structure organization; localization; lipid metabolic processes; regulation of cell adhesion; cell motion; cellular, organ and system development processes; etc. (Table 1)
It has been widely accepted that inflammation plays a critical role in colorectal cancer initiation, promotion, and progression, the mechanisms underlying CAC development are not clear
Summary
Colorectal cancer (CRC) is a major health problem worldwide. CRC develops through a multistage process involving the accumulation of genetic and epigenetic alterations [1]. Patients with inflammatory bowel disease (IBD) are at a higher risk for developing CRC than the general population. Several lines of evidence point to chronic inflammation of the colon as an important factor in the progression to CRC ( colitisassociated cancer [CAC]) in IBD [2]. Inflammationlinked carcinogenesis is a well-accepted concept, the underlying mechanisms have not been elucidated. Inflammation can provide tumor-initiating and tumor-promoting stimuli, along with mediators that generate a tumor-prone microenvironment [3,4,5]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
