Objective: The Warburg effect, also known as aerobic glycolysis, plays a dominant role in the development of gastrointestinal (GI) cancers. In this study, we analyzed the expression of key genes involved in the Warburg effect in GI cancers and investigated the effect of suppressing the Warburg effect in vitro in liver cancer cell lines.
Methods: The Cancer Genome Atlas (TCGA) RNA-Seq data were used to determine gene expression levels, which were analyzed with GraphPad Prism 7.00. Genetic alterations were queried with cBioPortal. The influence of the Warburg effect on liver cancer cell viability, migration and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) activity was determined by means of MTT, transwell and GAPDH activity assays.
Results: The levels of expression of genes associated with the Warburg effect were increased in tumors. To our knowledge, this is the first report of upregulated expression of CUEDC2 , HMGB2 , PFKFB4 , PFKP  and SIX1  in liver cancer. Clinically, overexpression of these genes was associated with significantly worse overall survival of liver cancer patients. In vitro, selective inhibition of GADPH suppressed the growth and metastasis of Huh-7, Bel7404 and Hep3B hepatocellular carcinoma cell lines.
Conclusion: The Warburg effect may play an important role in GI cancers, especially in liver cancer.
Keywords: Warburg effect, gastrointestinal cancers, liver cancer, bioinformatics, GAPDH