Promotion of adenoma growth by dietary inulin is associated with increase in cyclin D1 and decrease in adhesion proteins in Min/+ mice mucosa

• Published in: The Journal of nutritional biochemistry 2005-07, Vol.16 (7), p.402-409
• Main Authors: Misikangas, Marjo, Pajari, Anne-Maria, Päivärinta, Essi, Mutanen, Marja
• Format: Article
• Language: English
• Subjects: Adenoma - chemically induced; Adenoma - metabolism; Adenoma - pathology; Adhesion; animal models; Animals; beta Catenin; Biological and medical sciences; Cadherins - drug effects; Cadherins - metabolism; carcinogenesis; colorectal neoplasms; Cyclin D1; Cyclin D1 - drug effects; Cyclin D1 - metabolism; cyclins; Cytoskeletal Proteins - metabolism; Cytosol - metabolism; Diet; dietary fiber; Feeding. Feeding behavior; Female; Fundamental and applied biological sciences. Psychology; Intestinal Mucosa - drug effects; Intestinal Mucosa - metabolism; Intestinal Neoplasms - chemically induced; Intestinal Neoplasms - metabolism; Intestinal Neoplasms - pathology; Intestinal tumorigenesis; Inulin; Inulin - adverse effects; Male; Mice; Mice, Inbred C57BL; Mice, Mutant Strains; Min mouse; neoplasms; protein binding; Signal Transduction; Trans-Activators - metabolism; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Weight Gain
• ISSN: 0955-2863; 1873-4847
• DOI: 10.1016/j.jnutbio.2005.01.013

We have earlier shown that dietary fructo-oligosaccharide inulin enhances adenoma growth in multiple intestinal neoplasia (Min/+) mice. To further explore inulin-induced early biochemical changes in the normal-appearing mucosa, Min/+ mice were fed from the age of 5 weeks to the ages of 8 and 15 weeks a control diet or an inulin-enriched diet (10% w/w). In addition, the wild-type littermates were fed with the same diets until the age of 8 weeks, in order to determine whether similar changes happen both in the wild-type and Min/+ mice. The mucosa without adenomas was collected and fractionated to nuclear, cytosolic and membrane pools. The protein levels of β-catenin, cyclin D1 and E-cadherin were determined by Western blotting at both time points, and immunohistochemical stainings were done for 8-week-old mice. The promotion of adenoma growth by inulin (week 15, 1.3-fold increase, P=.0004) was associated with accumulation of cytosolic and nuclear β-catenin, and increased amount of cytosolic cyclin D1 (1.5-fold increase, P=.003) in the normal-appearing mucosa of the Min/+ mice. Furthermore, inulin feeding reduced the membranous pools of β-catenin and E-cadherin. Also in the wild-type mice the drop in membranous β-catenin was clear ( P=.015), and, moreover, a subset of crypts had enhanced nuclear β-catenin staining. These data indicate that dietary inulin can already activate in the normal-appearing mucosa β-catenin signaling, which in the presence of Apc mutation induces adenoma growth and even in the wild-type mice direction of the changes is similar.