Global gene expression analysis of knockdown Triosephosphate isomerase (TPI) gene in human gastric cancer cell line MGC-803

Our preview studies showed TPI gene which encodes the Triosephosphate isomerase was overexpressed in human gastric cancer (GC) tissues. However, the potential molecular mechanisms how TPI influences the GC development is not clear. Here, we performed global gene expression profiling for TPI knockdown using microarrays in human GC cell line MGC-803 cells. The differentially expressed genes (DEGs) were identified using reverse transcription-quantitative polymerase chain reaction analysis. Then the DEGs were analyzed by an online software WebGestalt to perform the functional analysis, pathway analysis and network analysis. The protein-protein interaction (PPI) networks were visualized by Cytoscape and the module analysis was performed by ClusterONE. As a result, a total of 920 DEGs including 197 up- and 723 down-regulated genes were screened out. The DEGs were found to be significantly associated with the metabolic process, biological regulation, protein binding and ion binding. There were 11 significant pathways were enriched, and one of the most significant pathway was transcriptional misregulation in cancer (P < 0.01), which contained common cancer-related genes, such as DUSP6, ETV5, IL6, PLAU, PPARG and HMGA2. Two PPI networks were constructed from BioGRID and TCGA_RNASeq_STAD, respectively. One network presented 25 genes with degree > 10, and EGFR was the most "hub gene" with degree of 74. Four significant modules were identified and mainly enriched in protein domain of Histone and G-protein beta WD-40 repeat. Another network had 4 significant modules and they were associated with protein domain of MHC class I-like antigen recognition and Epidermal growth factor receptor ligand. In conclusion, DEGs and hub genes identified in the present study help us understand the molecular mechanisms of TPI in the carcinogenesis and progression of gastric cancer.