Publication Date:
2009-07-22
Description:
Acquired uniparental disomy (aUPD) is a common feature of cancer genomes, leading to loss of heterozygosity. aUPD is associated not only with loss-of-function mutations of tumour suppressor genes, but also with gain-of-function mutations of proto-oncogenes. Here we show unique gain-of-function mutations of the C-CBL (also known as CBL) tumour suppressor that are tightly associated with aUPD of the 11q arm in myeloid neoplasms showing myeloproliferative features. The C-CBL proto-oncogene, a cellular homologue of v-Cbl, encodes an E3 ubiquitin ligase and negatively regulates signal transduction of tyrosine kinases. Homozygous C-CBL mutations were found in most 11q-aUPD-positive myeloid malignancies. Although the C-CBL mutations were oncogenic in NIH3T3 cells, c-Cbl was shown to functionally and genetically act as a tumour suppressor. C-CBL mutants did not have E3 ubiquitin ligase activity, but inhibited that of wild-type C-CBL and CBL-B (also known as CBLB), leading to prolonged activation of tyrosine kinases after cytokine stimulation. c-Cbl(-/-) haematopoietic stem/progenitor cells (HSPCs) showed enhanced sensitivity to a variety of cytokines compared to c-Cbl(+/+) HSPCs, and transduction of C-CBL mutants into c-Cbl(-/-) HSPCs further augmented their sensitivities to a broader spectrum of cytokines, including stem-cell factor (SCF, also known as KITLG), thrombopoietin (TPO, also known as THPO), IL3 and FLT3 ligand (FLT3LG), indicating the presence of a gain-of-function that could not be attributed to a simple loss-of-function. The gain-of-function effects of C-CBL mutants on cytokine sensitivity of HSPCs largely disappeared in a c-Cbl(+/+) background or by co-transduction of wild-type C-CBL, which suggests the pathogenic importance of loss of wild-type C-CBL alleles found in most cases of C-CBL-mutated myeloid neoplasms. Our findings provide a new insight into a role of gain-of-function mutations of a tumour suppressor associated with aUPD in the pathogenesis of some myeloid cancer subsets.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sanada, Masashi -- Suzuki, Takahiro -- Shih, Lee-Yung -- Otsu, Makoto -- Kato, Motohiro -- Yamazaki, Satoshi -- Tamura, Azusa -- Honda, Hiroaki -- Sakata-Yanagimoto, Mamiko -- Kumano, Keiki -- Oda, Hideaki -- Yamagata, Tetsuya -- Takita, Junko -- Gotoh, Noriko -- Nakazaki, Kumi -- Kawamata, Norihiko -- Onodera, Masafumi -- Nobuyoshi, Masaharu -- Hayashi, Yasuhide -- Harada, Hiroshi -- Kurokawa, Mineo -- Chiba, Shigeru -- Mori, Hiraku -- Ozawa, Keiya -- Omine, Mitsuhiro -- Hirai, Hisamaru -- Nakauchi, Hiromitsu -- Koeffler, H Phillip -- Ogawa, Seishi -- 2R01CA026038-30/CA/NCI NIH HHS/ -- England -- Nature. 2009 Aug 13;460(7257):904-8. doi: 10.1038/nature08240. Epub 2009 Jul 20.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Cancer Genomics Project, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19620960" target="_blank"〉PubMed〈/a〉
Keywords:
Allelic Imbalance
;
Amino Acid Sequence
;
Animals
;
Base Sequence
;
Chromosomes, Human, Pair 11/genetics
;
Female
;
*Genes, Tumor Suppressor
;
Humans
;
Leukemia, Myeloid/*genetics/metabolism/pathology
;
Male
;
Mice
;
Mice, Knockout
;
Mice, Nude
;
Models, Molecular
;
Molecular Sequence Data
;
Mutant Proteins/chemistry/genetics/*metabolism
;
Mutation
;
NIH 3T3 Cells
;
Neoplasm Transplantation
;
Oncogenes/genetics
;
Phosphorylation
;
Protein Conformation
;
Proto-Oncogene Proteins c-cbl/antagonists &
;
inhibitors/chemistry/deficiency/*genetics/*metabolism
;
Ubiquitination
;
Uniparental Disomy/genetics
;
ras Proteins/genetics/metabolism
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
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