Histone deacetylase inhibition selectively alters the activity and expression of cell cycle proteins leading to specific chromatin acetylation and antiproliferative effects.
Histone acetylation is emerging as a major regulatory mechanism thought to modulate gene expression by altering the accessibility of transcription factors to DNA. In this study, treatment of human tumor cells with the histone deacetylase inhibitor, trapoxin (TPX), resulted in selective changes in genes that control the cell cycle. TPX activated p21(waf1) transcription that led to elevated p21(waf1) protein levels in three human tumor cell lines without altering the protein levels of cdk2, cdk4, or cyclin B. In addition, TPX increased cyclin E transcription without increasing the levels of Rb, E2F, dihydrofolate reductase, or glyceraldehyde-3-phosphate dehydrogenase. The elevated levels of p21(waf1) protein led to decreased Rb phosphorylation and cdk2 activity. These effects resulted in G(1) and G(2) cell cycle arrest in H1299 human lung and MDA-MB-435 breast carcinoma cells and apoptosis in A549 lung carcinoma cells. Chromatin immunoprecipitation assays revealed that TPX increased the level of chromatin acetylation associated with histone H3 in the trapoxin-responsive region of the p21(waf1) promoter. This study demonstrates that inhibition of HDAC by TPX increases acetylation of H3-associated chromatin and alters gene expression with marked selectivity.
Sambucetti
L C
LC
Department of Oncology, Summit, New Jersey 07901, USA.
Fischer
D D
DD
Zabludoff
S
S
Kwon
P O
PO
Chamberlin
H
H
Trogani
N
N
Xu
H
H
Cohen
D
D
D000107:Acetylation / Q000187:drug effects; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D016203:CDC2 Protein Kinase / Q000378:metabolism; D002453:Cell Cycle; D002843:Chromatin / Q000378:metabolism*; D019927:Cyclin E / Q000378:metabolism; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000235:genetics / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005434:Flow Cytometry; D056572:Histone Deacetylase Inhibitors; D006655:Histone Deacetylases / Q000378:metabolism* / Q000494:pharmacology*; D006657:Histones / Q000235:genetics / Q000378:metabolism; D006801:Humans; D015151:Immunoblotting; D008856:Microscopy, Fluorescence; D010455:Peptides; D010766:Phosphorylation / Q000187:drug effects; D011233:Precipitin Tests; D011401:Promoter Regions, Genetic; D016160:Retinoblastoma Protein / Q000378:metabolism; D019311:Staurosporine / Q000494:pharmacology; D014162:Transfection; D014407:Tumor Cells, Cultured
D000900:Anti-Bacterial Agents; C493956:CDKN1A protein, human; D002843:Chromatin; D019927:Cyclin E; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D004791:Enzyme Inhibitors; D056572:Histone Deacetylase Inhibitors; D006657:Histones; D010455:Peptides; D016160:Retinoblastoma Protein; C067070:trapoxin A; D016203:CDC2 Protein Kinase; D006655:Histone Deacetylases; D019311:Staurosporine