Retinoic Acid (RA) treatment induces disease remission of Acute Promyelocytic Leukemias (APL) by triggering differentiation of neoplastic cells. Differentiation is mediated by the APL-specific transforming protein PML/RAR alpha and involves its activity as ligand-dependent enhancer factor on RA-target genes. We report here the identification of p21 as a transcriptional target of PML/RAR alpha during RA-induced differentiation of APL cells. We found that RA-treated APL cells undergo two rounds of cell division before entering post mitotic G1, that progression through the G1-S is indispensable for differentiation and coincides with the duration of commitment. RA-treatment induced two peaks of p21 synthesis: early (from the 2nd to the 6th hour), dependent on PML/RAR alpha expression and associated with G1-S transition and high CDK activity; late (from 3rd to the 4th day), independent from PML/RAR alpha and associated with G1 block and low CDK activity. Increased p21 in PML/RAR alpha cells during G1-S had no effect on the cell cycle while an antisense p21 prevented RA-induced differentiation without altering G1-S transition and the late G1 block. These results demonstrate that p21 is an effector of the activity of PML/RAR alpha on differentiation and suggest that p21 exerts a function in G1-S connected to differentiation-commitment and uncoupled from cell cycle and CDK inhibition.
|Titolo:||A function of p21 during promyelocytic leukemia cell differentiation independent of CDK inhibition and cell cycle arrest|
PELICCI, PIER GIUSEPPE (Ultimo)
|Parole Chiave:||APL; Cell cycle; p21; PML/RARα; RA|
|Settore Scientifico Disciplinare:||Settore MED/04 - Patologia Generale|
|Data di pubblicazione:||27-mag-1999|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1038/sj.onc.1202630|
|Appare nelle tipologie:||01 - Articolo su periodico|