Abstract 3686: Microarray analysis of dynamic regulation of genes in early and late stages of chemically induced esophageal carcinogenesis in rats.

Esophageal carcinogenesis is a multistage process characterized by morphological changes from normal esophagus to basal cell hyperplasia, dysplasia, carcinoma in situ and squamous cell carcinoma (SCC). Our laboratory has used the model of N-nitrosomethylbenzylamine (NMBA)-induced esophageal SCC in rats to investigate carcinogenesis and identify putative chemopreventive agents for this disease. The current study is part of large scale investigations on carcinogenesis of esophageal SCC. F344 rats were treated with NMBA (0.30 mg/kg b.w.) or a solution of 20% dimethyl sulfoxide (DMSO) in water (the solvent for NMBA) three times per week for five weeks. The esophageal tissues were collected at 6 and 29 weeks. The RNA pools from 3 individual RNA samples each were prepared for microarray analysis using Affymetrix Rat Genome 230 2.0 Array. Triplicate microarrays were completed for total 27 rats/9 microarrays. A P-value cutoff of 0.001 with a minimum 2.0-fold change was used to define the differently expressed genes. Ingenuity Pathway Analysis (IPA) software was used to identify cancer-related pathways and cellular functions. At 6 weeks (tumor incidence = 20%), 173 genes were modulated by NMBA when compared to control animals. Among which, 20 genes were associated with cancer, cellular development, cellular assembly and organization network; 34 genes were associated with inflammatory disease. The top five cellular functions altered by NMBA were cellular development, carbohydrate metabolism, cell death and survival, cellular growth and proliferation, and cellular function and maintenance. At 29 weeks (tumor incidence = 100%), we identified 1628 genes which were significantly up- or down-regulated by NMBA treatment when compared to normal animals and among which, 466 genes were involved in tumor development. In addition, we identified four cancer-related pathways (nuclear factor erythroid 2-related factor 2 mediated oxidative stress response, protein kinase A signaling, mitochondrial dysfunction, and AMP-activated kinase signaling) and five cellular functions (cellular development, cell morphology, cell death and survival, carbohydrate metabolism and molecular transport). Among genes altered during NMBA-induced esophageal carcinogenesis, 16 genes differently expressed only at 6 weeks including Gbp2, Psmb, Psmb9, Lgals3bp, Id1, Igfbp3, Agpat4, rCG_35099, Tes, RGD1563091, Cyp26b1, Itga1, Scarb1, LOC682861, Serpinb2 and Slfn3. The fold changes of Plcd4, Hbb, Bmper, Hba-a2, Defb4, LOC100134871 and LOC364653 increased from 6 weeks to 29 weeks. In conclusion, we identified differently expressed genes in early and late stages of NMBA-induced esophageal SCC by microarray analysis. Further investigations on biomarkers and cellular/molecular events during multistage of carcinogenesis in NMBA-rat preclinical model of esophageal SCC are underway. Citation Format: Ni Shi, Ronald G. Nines, Lianbo Yu, Michael J. Nicholl, Tong Chen. Microarray analysis of dynamic regulation of genes in early and late stages of chemically induced esophageal carcinogenesis in rats. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3686. doi:10.1158/1538-7445.AM2013-3686