c-Myb down-regulation is associated with human colon cell differentiation, apoptosis, and decreased Bcl-2 expression

c-myb is expressed in human and murine colonic mucosa and elevated expression occurs in premalignant adenomatous polyps and carcinomas. c-Myb is required for colon cell proliferation, and there is evidence of c-myb down-regulation during differentiation. Recently, c-myb has been implicated in hemato...

Full description

Saved in:
Bibliographic Details
Published in:Cancer research (Chicago, Ill.) Ill.), 1998-11, Vol.58 (22), p.5168-5175
Main Authors: THOMPSON, M. A, ROSENTHAL, M. A, ELLIS, S. L, FRIEND, A. J, ZORBAS, M. I, WHITEHEAD, R. H, RAMSAY, R. G
Format: Article
Language:English
Subjects:
Alkaline Phosphatase - metabolism
Apoptosis - genetics
Biological and medical sciences
Butyrates - pharmacology
Cell Differentiation - genetics
Colon - cytology
Colon - drug effects
Colon - metabolism
Colon - ultrastructure
Colonic Neoplasms - metabolism
Colonic Neoplasms - pathology
DNA Fragmentation
Down-Regulation
Enzyme Induction
Gastroenterology. Liver. Pancreas. Abdomen
Gene Amplification
Genes, bcl-2
Humans
Medical sciences
Oncogenes
Proto-Oncogene Proteins c-bcl-2 - genetics
Proto-Oncogene Proteins c-bcl-2 - metabolism
Stomach. Duodenum. Small intestine. Colon. Rectum. Anus
Tumor Cells, Cultured - drug effects
Tumors
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:c-myb is expressed in human and murine colonic mucosa and elevated expression occurs in premalignant adenomatous polyps and carcinomas. c-Myb is required for colon cell proliferation, and there is evidence of c-myb down-regulation during differentiation. Recently, c-myb has been implicated in hematopoietic cell survival via regulation of bcl-2 gene expression. However, c-myb expression during terminal differentiation and apoptosis in the colonic crypt has not been examined. The experiments in this study examine the spatial and temporal expression of c-Myb protein in vivo using human colonic crypt sections and in vitro in human colon tumor cell lines undergoing butyrate-induced differentiation and apoptosis. Electron microscopy, together with molecular and biochemical analysis, was used to define the differentiation status of the cells. Results demonstrate a decrease in c-Myb expression during the commitment of cells to differentiation and apoptosis. Decreased levels of c-Myb are accompanied by a decrease in Bcl-2. These data suggest that the transcription factor c-Myb has a role in regulating the balance between proliferation, differentiation, and apoptosis in the colonic crypt. Furthermore, elevated c-Myb levels in colon tumor cells may lead to persistent bcl-2 expression, thus protecting tumor cells from programmed cell death.
ISSN:0008-5472
1538-7445