Open AccessA role for candidate tumor-suppressor gene TCEAL7 in the regulation of c-Myc activity, cyclin D1 levels and cellular transformation
Author(s) -
Jeremy Chien,
Keishi Narita,
Ramandeep Rattan,
Shailendra Giri,
Ravi Shridhar,
Julie Staub,
Daniah Beleford,
JennHaung Lai,
Lewis R. Roberts,
Julian R. Molina,
Scott H. Kaufmann,
G. C. Prendergast,
Viji Shridhar
Publication year - 2008
Publication title -
oncogene
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.395
H-Index - 342
eISSN - 1476-5594
pISSN - 0950-9232
DOI - 10.1038/onc.2008.360
Subject(s) - biology , cyclin d1 , downregulation and upregulation , cancer research , ornithine decarboxylase , ovarian cancer , carcinogenesis , proto oncogene proteins c myc , cell cycle , e2f , cell growth , promoter , transcriptional regulation , cancer , microbiology and biotechnology , gene expression , gene , genetics , enzyme , biochemistry
The pathophysiological mechanisms that drive the development and progression of epithelial ovarian cancer remain obscure. Recently, we identified TCEAL7 as a transcriptional regulatory protein often downregulated in epithelial ovarian cancer. However, the biological significance of such downregulation in cancer is not currently known. Here, we show that TCEAL7 is downregulated frequently in many human cancers and that in immortalized human ovarian epithelial cells this event promotes anchorage-independent cell growth. Mechanistic investigations revealed that TCEAL7 associates with cyclin D1 promoter containing Myc E-box sequence and transcriptionally represses cyclin D1 expression. Moreover, downregulation of TCEAL7 promotes DNA-binding activity of Myc-Max, and upregulates the promoter activity of c-Myc-target gene, ornithine decarboxylase (ODC), whereas enhanced expression of TCEAL7 inhibits Myc-induced promoter activity of ODC. Our findings suggest that TCEAL7 may restrict ovarian epithelial cell transformation by limiting Myc activity. These results also suggest a potential, alternative mechanism by which c-Myc activity may be deregulated in cancer by the downregulation of TCEAL7.