Proteomic analysis of intestinal epithelial cells expressing stabilized beta-catenin.
Aberrant accumulation of beta-catenin protein because of mutation of either the beta-catenin or adenomatous polyposis coli gene plays an essential role in the development of colorectal carcinoma. We established previously a stable clone of the rat small intestinal epithelial cell line IEC6, which is capable of inducing stabilized beta-catenin protein lacking NH(2)-terminal glycogen synthase kinase-3beta phosphorylation site under a strict control of the tetracycline-regulatory system. This clone, IEC6-TetOFF-beta-catenin DeltaN89, shows in vitro polypoid growth on the removal of doxycycline and seems to be an appropriate model for analyzing the molecular mechanisms of early intestinal carcinogenesis. Of >2000 protein spots displayed by newly developed two-dimensional difference gel electrophoresis, 22 were found to be up- or down-regulated on the induction of stabilized beta-catenin. The majority of these proteins fell into two categories: (a) redox-status regulatory proteins and (b) cytoskeleton-associated proteins. Representatively, a key redox-status regulatory protein, manganese superoxide dismutase, up-regulated in IEC6 cells expressing stabilized beta-catenin protein, was overexpressed in adenoma and adenocarcinoma cells of familial adenomatous polyposis patients in parallel with the accumulation of beta-catenin. These results suggest that aberrant accumulation of beta-catenin might contribute to colorectal carcinogenesis by affecting redox status in the mitochondria of intestinal epithelial cells.
Seike
Masahiro
M
Cancer Proteomics Project, National Cancer Center Research Institute, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045, Japan.
Kondo
Tadashi
T
Mori
Yasuharu
Y
Gemma
Akihiko
A
Kudoh
Shoji
S
Sakamoto
Michiie
M
Yamada
Tesshi
T
Hirohashi
Setsuo
S
D000230:Adenocarcinoma / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D000236:Adenoma / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D000818:Animals; D015179:Colorectal Neoplasms / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D003598:Cytoskeletal Proteins / Q000096:biosynthesis* / Q000235:genetics; D004847:Epithelial Cells / Q000378:metabolism / Q000502:physiology; D005786:Gene Expression Regulation; D007421:Intestine, Small / Q000378:metabolism* / Q000502:physiology; D013058:Mass Spectrometry; D020543:Proteome / Q000096:biosynthesis* / Q000235:genetics; D040901:Proteomics; D051381:Rats; D013482:Superoxide Dismutase / Q000096:biosynthesis / Q000235:genetics; D015534:Trans-Activators / Q000096:biosynthesis* / Q000235:genetics; D051176:beta Catenin
C495268:Ctnnb1 protein, rat; D003598:Cytoskeletal Proteins; D020543:Proteome; D015534:Trans-Activators; D051176:beta Catenin; D013482:Superoxide Dismutase