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Transcriptional Regulation of p21/CIP1 Cell Cycle Inhibitor by PDEF Controls Cell Proliferation and Mammary Tumor Progression
- Source :
- Journal of Biological Chemistry. 285:11258-11269
- Publication Year :
- 2010
- Publisher :
- Elsevier BV, 2010.
-
Abstract
- The Ets family of transcription factors control a myriad of cellular processes and contribute to the underlying genetic loss of cellular homeostasis resulting in cancer. PDEF (prostate-derived Ets factor) has been under investigation for its role in tumor development and progression. However, the role of PDEF in cancer development has been controversial. Some reports link PDEF to tumor promoter, and others show tumor-suppressing functions in various systems under different conditions. So far, there has been no conclusive evidence from in vivo experiments to prove the role of PDEF. We have used both in vitro and in vivo systems to provide a conclusive role of PDEF in the progression process. PDEF-expressing cells block the cell growth rate, and this retardation was reversible when PDEF expression was silenced with PDEF-specific small interfering RNA. When these PDEF-expressing cells were orthotopically implanted into the mouse mammary gland, tumor incidence and growth rate were significantly retarded. Cell cycle analysis revealed that PDEF expression partially blocked cell cycle progression at G(1)/S without an effect on apoptosis. PDEF overexpression resulted in an increase in p21/CIP1 at both the mRNA and protein levels, resulting in decreased Cdk2 activity. Promoter deletion analysis, electrophoresis mobility shift assays, and chromatin immunoprecipitation studies identified the functional Ets DNA binding site at -2118 bp of the p21/CIP1 gene promoter. This site is capable of binding and responding to PDEF. Furthermore, we silenced p21/CIP1 expression in PDEF-overexpressing cells by small interfering RNA. p21-silenced PDEF cells exhibited significantly increased cell growth in vitro and in vivo, demonstrating the p21 regulation by PDEF as a key player. These experiments identified PDEF as a new transcription factor that directly regulates p21/CIP1 expression under non-stressed conditions. This study conclusively proves that PDEF is a breast tumor suppressor for the first time using both in vitro and in vivo systems. PDEF can be further developed as a target for designing therapeutic intervention of breast cancer.
- Subjects :
- Cyclin-Dependent Kinase Inhibitor p21
Small interfering RNA
Cellular homeostasis
Apoptosis
Mammary Neoplasms, Animal
Biology
Biochemistry
Mice
Cell Line, Tumor
Transcriptional regulation
Animals
Humans
Gene silencing
Gene Regulation
Gene Silencing
Molecular Biology
Transcription factor
Cell Proliferation
Proto-Oncogene Proteins c-ets
Cell growth
Cell Cycle
Cell Biology
Cell cycle
Gene Expression Regulation, Neoplastic
Cancer research
Female
Chromatin immunoprecipitation
Neoplasm Transplantation
Subjects
Details
- ISSN :
- 00219258
- Volume :
- 285
- Database :
- OpenAIRE
- Journal :
- Journal of Biological Chemistry
- Accession number :
- edsair.doi.dedup.....90c5f11dd1fa5b051f9a68a7454f1eb3