Integrated expression analysis identifies transcription networks in mouse and human gastric neoplasia

Abstract

Gastric cancer (GC) is a leading cause of cancer-related deaths worldwide. The Tff1 knockout (KO) mouse model develops gastric lesions that include low-grade dysplasia (LGD), high-grade dysplasia (HGD), and adenocarcinomas. In this study, we used Affymetrix microarrays gene expression platforms for analysis of molecular signatures in the mouse stomach [Tff1-KO (LGD) and Tff1 wild-type (normal)] and human gastric cancer tissues and their adjacent normal tissue samples. Combined integrated bioinformatics analysis of mouse and human datasets indicated that 172 genes were consistently deregulated in both human gastric cancer samples and Tff1-KO LGD lesions (P < .05). Using Ingenuity pathway analysis, these genes mapped to important transcription networks that include MYC, STAT3, β-catenin, RELA, NFATC2, HIF1A, and ETS1 in both human and mouse. Further analysis demonstrated activation of FOXM1 and inhibition of TP53 transcription networks in human gastric cancers but not in Tff1-KO LGD lesions. Using real-time RT-PCR, we validated the deregulated expression of several genes (VCAM1, BGN, CLDN2, COL1A1, COL1A2, COL3A1, EpCAM, IFITM1, MMP9, MMP12, MMP14, PDGFRB, PLAU, and TIMP1) that map to altered transcription networks in both mouse and human gastric neoplasia. Our study demonstrates significant similarities in deregulated transcription networks in human gastric cancer and gastric tumorigenesis in the Tff1-KO mouse model. The data also suggest that activation of MYC, STAT3, RELA, and β-catenin transcription networks could be an early molecular step in gastric carcinogenesis.

Figure 1. Transcriptional network analysis demonstrates activation of MYC, STAT3 and β-catenin

Pathway analysis of gene expression data using Ingenuity online tools indicated activation of MYC, STAT3 and β-catenin (CTNNB1) transcription networks in both Tff1 KO mice gastric LGD and human gastric cancer samples.

Figure 2. Validation of representative MYC, STAT3 and β-catenin downstream target genes in gastric tissue samples from mice

qRT-PCR analysis of expression of targets genes, as shown, was performed in normal glandular stomach of 10 wild-type (WT), 10 Tff1 KO with low-grade dysplasia (LGD), and 9 Tff1 KO with high-grade dysplasia (HGD). The horizontal line indicates the median. *P<0.05, **P<0.01, ***P<0.001, Mann-Whitney U test.

Figure 3. Validation of representative MYC, STAT3 and β-catenin downstream target genes in human gastric tissue samples

qRT-PCR analysis of expression of target genes, as shown, in 19 human normal stomach (NG) and 22 gastric cancer (GC) tissue samples. The horizontal line indicates the median *P<0.05, **P<0.01, ***P<0.001, Mann-Whitney U test