Document Detail

p21(Waf1) is required for cellular senescence but not for cell cycle arrest induced by the HDAC inhibitor sodium butyrate.
MedLine Citation:
PMID:  20935470     Owner:  NLM     Status:  In-Process    
Cell senescence is characterized by senescent morphology and permanent loss of proliferative potential. HDAC inhibitors (HDACI) induce senescence and/or apoptosis in many types of tumor cells. Here, we studied the role of cyclin-kinase inhibitor p21(waf1) (Cdkn1n gene) in cell cycle arrest, senescence markers (cell hypertrophy, SA-βGal staining and accumulation of γH2AX foci) in p21(Waf1+/+) versus p21(Waf1-/-) mouse embryonic fibroblast cells transformed with E1A and cHa-Ras oncogenes (mERas). While short treatment with the HDACI sodium butyrate (NaB) induced a reversible G(1) cell cycle arrest in both parental and p21(Waf1-/-) cells, long-term treatment led to dramatic changes in p21(Waf1+/+) cells only: cell cycle arrest became irreversible and cells become hypertrophic, SA-βGal-positive and accumulated γH2AX foci associated with mTORC1 activation. The p21(Waf1+/+) cells lost their ability to migrate into the wound and through a porous membrane. Suppression of migration was accompanied by accumulation of vinculin-staining focal adhesions and Ser3-phosphorylation of cofilin, incapable for F-actin depolymerization. In contrast, the knockout of the p21(Waf1) abolished most of the features of NaB-induced senescence, including irreversibility of cell cycle arrest, hypertrophy, additional focal adhesions and block of migration, γH2AX foci accumulation and SA-βGal staining. Rapamycin, a specific inhibitor of mTORC1 kinase, decreased cellular hypertrophy, canceled coffilin phosphorylation and partially restored cell migration in p21(Waf1+/+) cells. Taken together, our data indicate a new role of p21(Waf1) in cell senescence, which may be connected not only with execution of cell cycle arrest, but also with the development of mTOR-dependent markers of cellular senescence.
V S Romanov; M V Abramova; S B Svetlikova; T V Bykova; S G Zubova; N D Aksenov; A J Fornace; T V Pospelova; V A Pospelov
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2010-10-26
Journal Detail:
Title:  Cell cycle (Georgetown, Tex.)     Volume:  9     ISSN:  1551-4005     ISO Abbreviation:  Cell Cycle     Publication Date:  2010 Oct 
Date Detail:
Created Date:  2010-10-27     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101137841     Medline TA:  Cell Cycle     Country:  United States    
Other Details:
Languages:  eng     Pagination:  3945-55     Citation Subset:  IM    
Institute of Cytology, Russian Academy of Sciences, St. Petersburg, Russia.
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