Document Detail


Impaired cell cycle regulation of the osteoblast-related heterodimeric transcription factor Runx2-Cbfbeta in osteosarcoma cells.
MedLine Citation:
PMID:  19739101     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Bone formation and osteoblast differentiation require the functional expression of the Runx2/Cbfbeta heterodimeric transcription factor complex. Runx2 is also a suppressor of proliferation in osteoblasts by attenuating cell cycle progression in G(1). Runx2 levels are modulated during the cell cycle, which are maximal in G(1) and minimal beyond the G(1)/S phase transition (S, G(2), and M phases). It is not known whether Cbfbeta gene expression is cell cycle controlled in preosteoblasts nor how Runx2 or Cbfbeta are regulated during the cell cycle in bone cancer cells. We investigated Runx2 and Cbfbeta gene expression during cell cycle progression in MC3T3-E1 osteoblasts, as well as ROS17/2.8 and SaOS-2 osteosarcoma cells. Runx2 protein levels are reduced as expected in MC3T3-E1 cells arrested in late G(1) (by mimosine) or M phase (by nocodazole), but not in cell cycle arrested osteosarcoma cells. Cbfbeta protein levels are cell cycle independent in both osteoblasts and osteosarcoma cells. In synchronized MC3T3-E1 osteoblasts progressing from late G1 or mitosis, Runx2 levels but not Cbfbeta levels are cell cycle regulated. However, both factors are constitutively elevated throughout the cell cycle in osteosarcoma cells. Proteasome inhibition by MG132 stabilizes Runx2 protein levels in late G(1) and S in MC3T3-E1 cells, but not in ROS17/2.8 and SaOS-2 osteosarcoma cells. Thus, proteasomal degradation of Runx2 is deregulated in osteosarcoma cells. We propose that cell cycle control of Runx2 gene expression is impaired in osteosarcomas and that this deregulation may contribute to the pathogenesis of osteosarcoma.
Authors:
Inga A San Martin; Nelson Varela; Marcia Gaete; Karina Villegas; Mariana Osorio; Julio C Tapia; Marcelo Antonelli; Edna E Mancilla; Barry P Pereira; Saminathan S Nathan; Jane B Lian; Janet L Stein; Gary S Stein; Andre J van Wijnen; Mario Galindo
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of cellular physiology     Volume:  221     ISSN:  1097-4652     ISO Abbreviation:  J. Cell. Physiol.     Publication Date:  2009 Dec 
Date Detail:
Created Date:  2009-10-01     Completed Date:  2009-11-13     Revised Date:  2011-08-01    
Medline Journal Info:
Nlm Unique ID:  0050222     Medline TA:  J Cell Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  560-71     Citation Subset:  IM    
Affiliation:
Faculty of Medicine, Institute of Biomedical Sciences ICBM, University of Chile, Santiago, Chile.
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MeSH Terms
Descriptor/Qualifier:
Animals
Cell Cycle / physiology*
Cell Line
Cell Line, Tumor
Core Binding Factor Alpha 1 Subunit / genetics,  metabolism*
Core Binding Factor beta Subunit / genetics,  metabolism*
Cysteine Proteinase Inhibitors
G1 Phase / physiology
Gene Expression / genetics
Gene Expression Regulation, Neoplastic / physiology*
Humans
Leupeptins / pharmacology
Mice
Mitosis / physiology
Osteoblasts / cytology,  metabolism
Osteosarcoma / metabolism*,  pathology
Proteasome Endopeptidase Complex / antagonists & inhibitors,  metabolism
Rats
Ubiquitination / drug effects
Grant Support
ID/Acronym/Agency:
AR49069/AR/NIAMS NIH HHS; CA082834/CA/NCI NIH HHS; P01 CA082834-09/CA/NCI NIH HHS; P01 CA082834-090007/CA/NCI NIH HHS; P01 CA082834-11/CA/NCI NIH HHS; R01 AR049069-05/AR/NIAMS NIH HHS
Chemical
Reg. No./Substance:
0/Core Binding Factor Alpha 1 Subunit; 0/Core Binding Factor beta Subunit; 0/Cysteine Proteinase Inhibitors; 0/Leupeptins; 133407-82-6/benzyloxycarbonylleucyl-leucyl-leucine aldehyde; EC 3.4.25.1/Proteasome Endopeptidase Complex
Comments/Corrections

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