Glucose utilisation and cell proliferation in colorectal cancer

Role of glucose metabolism related gene GLUT1 in the occurrence and prognosis of colorectal cancer

Colorectal cancer (CRC) ranks the third most commonly diagnosed cancer in males and the second in females worldwide. However, the functional and causal SNPs for CRC remain to be mined. Glucose transporter 1 (GLUT1), a pivotal rate-limiting element in the transport of glucose in malignancy cells, has been identified to be associated with many cancers. Here, we aim to explore the role of GLUT1 in the occurrence and prognosis of colorectal cancer in a Chinese population. We found that GLUT1 expression levels in CRC tumor tissues were significantly higher than those in the corresponding adjacent normal tissues, and Cox multivariate analysis demonstrated that the GLUT1 expression was an independent prognostic factor for CRC (HR = 2.11, 95% CI = 1.33–3.34, P=0.001). For a functional polymorphism of GLUT1 (rs710218), we found that individuals with TT genotype (OR = 1.68, 95% CI = 1.02-2.75, P = 0.041) or AT genotype (OR = 1.47, 95% CI = 1.09-1.99, P = 0.012) of rs710218 had a significantly increased risk of CRC compared to those with AA homozygote. These findings strongly suggest that glucose metabolism related gene GLUT1, and its functional SNP, rs710218 might contribute to CRC susceptibility and prognosis, and the exact biological mechanism awaits further research.

Fatty acid metabolism pathway play an important role in carcinogenesis of human colorectal cancers by Microarray-Bioinformatics analysis

The present study systematically explored metabolic pathways and altered expressions of genes speculatively participating in colorectal carcinogenesis by using a Microarray-Bioinformatic analysis methods. The results revealed that 157 genes were up-regulated and 281 genes were down-regulated in colorectal cancer (CRC). Gene Ontology (GO) and relevant bioinformatics tools indicated that the functional category to which 438 genes (12%; 438/3800) of the most frequent alteration belonged was metabolism. The analysis of 10 colorectal cancer tissue specimens demonstrated that genes involved in fatty acid metabolic pathways had high rates of overexpression. In addition, we stimulated CRL-1790 cell line with linoleic acid (a polyunsaturated fatty acid) for 12, 24, 48 and 72 h. Cell proliferation was elevated by 5, 25, 28 and 31% (P<0.05), respectively. Further analyses revealed that the genes increasingly expressed in the cell line included enoyl-Coenzyme A, hydratase/3-hydroxyacyl Coenzyme A dehydrogenase (EHHADH), enoyl Coenzyme A hydratase, short chain, 1, mitochondrial (ECHS1); glutaryl-Coenzyme A dehydrogenase (GCDH), acyl-Coenzyme A oxidase 2, branched chain (ACOX2); acyl-Coenzyme A dehydrogenase, C-2 to C-3 short chain precursor (ACADS); carnitine palmitoyltransferase 1B (CPT1B), acyl-CoA synthetase long-chain family member 5 (ACSL5), and cytochrome P450, family 4, subfamily A, and polypeptide 11 (CYP4A11) genes. This indicated that the stimulating effect of linoleic acid on cell proliferation was due to interference with the metabolic pathway of fatty acid metabolism. In conclusion, genes with altered expression levels in CRC were mainly associated with fatty acid metabolic pathways speculated to have an important role linked to carcinogenesis.