Molecular changes in the expression of human colonic nutrient transporters during the transition from normality to malignancy.
Bottom Line: Butyrate has profound effects on differentiation, proliferation and apoptosis of colonic epithelial cells by regulating expression of various genes associated with these processes.This was reflected in a corresponding reduction in MCT1 mRNA expression, as measured by Northern analysis.Carcinoma samples displaying reduced levels of MCT1 were found to express the high affinity glucose transporter, GLUT1, suggesting that there is a switch from butyrate to glucose as an energy source in colonic epithelia during transition to malignancy.
Affiliation: Department of Veterinary Preclinical Sciences, University of Liverpool, Liverpool L69 7ZJ, UK.Show MeSH
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Mentions: We have shown previously by immunoblotting that the butyrate transporter, MCT1, is enriched 30-fold in the luminal membranes isolated from healthy human colonic tissue compared to the cellular homogenate, indicating that the protein is predominantly located on the luminal membrane of human colonocytes (Ritzhaupt et al, 1998b). Here, using immunohistochemistry, we sought to confirm and extend this observation to investigate the pattern of MCT1 expression along the crypt-surface axis. Immunohistochemical detection of MCT1 using a horseradish peroxidase-conjugated secondary antibody confirmed that MCT1 is predominantly located on the luminal membrane of healthy colonocytes (Figure 1AFigure 1
Affiliation: Department of Veterinary Preclinical Sciences, University of Liverpool, Liverpool L69 7ZJ, UK.