Histone deacetylase inhibitors upregulate p57Kip2 level by enhancing its expression through Sp1 transcription factor.
Histone deacetylase inhibitors (HDACIs) represent a new class of targeted anticancer agents. Here, we evaluate the effects of butyrate (BuA) and other HDACIs on p57(Kip2), a cyclin-dependent kinase inhibitor (cki). We observed that inhibitors of class I/II histone deacetylases (HDACs), but not of class III HDACs, induce a remarkable accumulation of p57(Kip2) in several cells. The cki upregulation is associated with an increased gene expression that was not prevented by cycloheximide, indicating that HDACIs affect directly p57(Kip2) transcription. The characterization of p57(Kip2) promoter indicates that the first 165 bp are mostly involved in the BuA effects. Chromatin immunoprecipitation studies demonstrated that the BuA treatment causes the recruitment of Sp1 transcription factor. The Sp1 importance was confirmed by the reduction of BuA effects by mithramycin A (an Sp1 antagonist) and, most stringently, by Sp1 downregulation due to Sp1 siRNA. Moreover, both the treatments reduce the p57(Kip2) transcription in untreated cells, suggesting that Sp1 is required for the constitutive cki expression. Studies employing plasmids containing parts of the 165 bp of p57(Kip2) promoter indicate that the promoter region between -87 and -113 bp, which includes two putative Sp1 consensus sequences, plays a critical role in the response to HDACIs. Since this p57(Kip2) promoter region also embraces the consensus sequence for the transcriptional repressor chicken ovalbumin upstream promoter transcription factor-interacting protein 2 (CTIP2), we evaluated whether this factor is involved into the BuA effect. When CTIP2 was downregulated by a specific siRNA, we observed the enhancement of BuA activity on p57(Kip2) expression suggesting that CTIP2 might also be involved in HDACIs effects.
Cucciolla
Valeria
V
Department of Biochemistry and Biophysics F. Cedrangolo, Second University of Naples, Via Costantinopoli 16, 80138, Naples, Italy.
Borriello
Adriana
A
Criscuolo
Maria
M
Sinisi
Antonio A
AA
Bencivenga
Debora
D
Tramontano
Annunziata
A
Scudieri
Anna Chiara
AC
Oliva
Adriana
A
Zappia
Vincenzo
V
Della Ragione
Fulvio
F
D000107:Acetylation; D001483:Base Sequence; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D047369:Chromatin Immunoprecipitation; D050761:Cyclin-Dependent Kinase Inhibitor p57 / Q000235:genetics / Q000378:metabolism*; D017931:DNA Primers; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D016193:G1 Phase / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects; D056572:Histone Deacetylase Inhibitors; D006801:Humans; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016329:Sp1 Transcription Factor / Q000378:metabolism*; D014158:Transcription, Genetic
C493964:CDKN1C protein, human; D050761:Cyclin-Dependent Kinase Inhibitor p57; D017931:DNA Primers; D004791:Enzyme Inhibitors; D056572:Histone Deacetylase Inhibitors; D016329:Sp1 Transcription Factor