Hdm2 is regulated by K-Ras and mediates p53-independent functions in pancreatic cancer cells
| Autor: | Sonyo Shin, Ruo Dan Zhang, Pervez F. Firozi, Shrikanth A.G. Reddy, X Sui, James L. Abbruzzese, L Yang |
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| Rok vydání: | 2008 |
| Předmět: |
Cancer Research
Tumor suppressor gene Cell Survival Genes myc Biology medicine.disease_cause Cyclin D1 Genes jun Pancreatic cancer Cell Line Tumor Genetics medicine Humans Molecular Biology Cell Proliferation Regulation of gene expression Cell growth c-jun Proto-Oncogene Proteins c-mdm2 medicine.disease MAP Kinase Kinase Kinases Genes bcl-1 Gene Expression Regulation Neoplastic Pancreatic Neoplasms Genes ras Cell culture Cancer research Mutant Proteins raf Kinases Tumor Suppressor Protein p53 Carcinogenesis Signal Transduction |
| Zdroj: | Oncogene. 28(5) |
| ISSN: | 1476-5594 |
| Popis: | There is emerging evidence that the oncogenic potential of hdm2 (human and/or murine double minute-2 protein) stems not only from its ability to counteract tumor suppressor p53 but also from its less understood p53-independent functions. Surprisingly, little is known about the role and regulation of hdm2 in pancreatic tumors, a large proportion (50-75%) of which contain mutant p53. In this study, we determined that hdm2 was expressed in a Ras-signaling-dependent manner in various pancreatic cancer cell lines. As p53 was mutated and inactive in these cells, the expression of hdm2 was seemingly redundant. Indeed, the proliferation and survival of cell lines such as Panc-1 and Panc-28 could be inhibited by PRIMA-1 (mutant p53 activator) but not by Nutlin-3 (inhibitor of the hdm2-p53 interaction). Unexpectedly, however, the proliferation of both cell lines was strongly inhibited by hdm2-specific RNAi. Our data also revealed cyclin D1, c-Jun and c-Myc to be novel targets of hdm2 and suggested that they might mediate hdm2's role in cellular proliferation and/or survival. We conclude from our results that hdm2 is expressed in pancreatic cancer cells as a result of activated Ras signaling, and that it regulates cellular proliferation and the expression of three novel target genes by p53-independent mechanisms. |
| Databáze: | OpenAIRE |
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