Details

Autor(en) / Beteiligte

• THOMPSON, M. A
• ROSENTHAL, M. A
• ELLIS, S. L
• FRIEND, A. J
• ZORBAS, M. I
• WHITEHEAD, R. H
• RAMSAY, R. G

Titel

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

Ist Teil von

• Cancer research (Chicago, Ill.), 1998-11, Vol.58 (22), p.5168-5175

Ort / Verlag

Philadelphia, PA: American Association for Cancer Research

Erscheinungsjahr

1998

Quelle

MEDLINE

Beschreibungen/Notizen

• 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.