Transforming growth factor β1 (TGF-β1) inhibits retinoblastoma gene expression but not pRB phosphorylation in TGF-β1-growth stimulated colon carcinoma cells Journal Article
| Authors: | Yan, Z.; Hsu, S.; Winawer, S.; Friedman, E. |
| Article Title: | Transforming growth factor β1 (TGF-β1) inhibits retinoblastoma gene expression but not pRB phosphorylation in TGF-β1-growth stimulated colon carcinoma cells |
| Abstract: | The response of the retinoblastoma (RB) gene and its product (pRB) to transforming growth factor β1 (TGF-β1) was studied in three types of colon carcinoma cells derived from the same parental line. TGF-β1 was a growth inhibitor for two enterocytic-differentiated lines, a growth stimulator for two undifferentiated lines, and had no effect on two goblet cell-differentiated lines. TGF-β1 treatment for 3 days decreased RB gene expression and pRB level two- to threefold in each responsive line. When treated with TGF-β1 beginning in early G1, enterocytic cells were arrested in G1 and pRB remained underphosphorylated and in low abundance. Neither goblet cell line exhibited these responses to TGF-β1 because they were shown to lack TGF-β1 type I and II receptors. Thus during colonocyte differentiation goblet cells lose responsiveness to TGF-β1 by down-regulating TGF-β1 receptors, while enterocytic cells retain and exhibit responsiveness to TGF-β1 through modulations of pRB. Both of the undifferentiated lines exhibited mixed responses to TGF-β1 a decrease in total amount of RB mRNA and pRB protein yet an increase in pRB phosphorylation consistent with increased cell cycling. Therefore, TGF-β1 controls RB function by two separable mechanisms, the regulation of pRB phosphorylation and the control of RB mRNA and protein level. |
| Keywords: | protein phosphorylation; human cell; cell cycle; gene expression; transforming growth factor beta; colonic neoplasms; gene function; cell differentiation; tumor cells, cultured; phosphorylation; tumor suppressor gene; messenger rna; gene repression; tumor cell line; carcinoma; transforming growth factor beta1; colon carcinoma; cell level; retinoblastoma protein; intestine cell; cell cycle g1 phase; in vitro; goblet cell; growth inhibition; growth factor receptor; genes, retinoblastoma; growth stimulation; trixis; human; priority journal; article |
| Journal Title: | Oncogene |
| Volume: | 7 |
| Issue: | 4 |
| ISSN: | 0950-9232 |
| Publisher: | Nature Publishing Group |
| Date Published: | 1992-04-01 |
| Start Page: | 801 |
| End Page: | 805 |
| Language: | English |
| PUBMED: | 1565477 |
| PROVIDER: | scopus |
| DOI/URL: | |
| Notes: | Source: Scopus |
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