Polyisoprenylated benzophenone, garcinol, a natural histone acetyltransferase inhibitor, represses chromatin transcription and alters global gene expression.
Histone acetylation is a diagnostic feature of transcriptionally active genes. The proper recruitment and function of histone acetyltransferases (HATs) and deacetylases (HDACs) are key regulatory steps for gene expression and cell cycle. Functional defects of either of these enzymes may lead to several diseases, including cancer. HATs and HDACs thus are potential therapeutic targets. Here we report that garcinol, a polyisoprenylated benzophenone derivative from Garcinia indica fruit rind, is a potent inhibitor of histone acetyltransferases p300 (IC50 approximately 7 microm) and PCAF (IC50 approximately 5 microm) both in vitro and in vivo. The kinetic analysis shows that it is a mixed type of inhibitor with an increased affinity for PCAF compared with p300. HAT activity-dependent chromatin transcription was strongly inhibited by garcinol, whereas transcription from DNA template was not affected. Furthermore, it was found to be a potent inducer of apoptosis, and it alters (predominantly down-regulates) the global gene expression in HeLa cells.
Balasubramanyam
Karanam
K
Transcription and Disease Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore-560064, India.
Altaf
M
M
Varier
Radhika A
RA
Swaminathan
V
V
Ravindran
Aarti
A
Sadhale
Parag P
PP
Kundu
Tapas K
TK
D000123:Acetyltransferases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005638:Fruit / Q000737:chemistry; D029760:Garcinia / Q000737:chemistry; D005786:Gene Expression Regulation / Q000187:drug effects*; D006367:HeLa Cells; D051548:Histone Acetyltransferases; D006801:Humans; D007700:Kinetics; D015394:Molecular Structure; D020411:Oligonucleotide Array Sequence Analysis; D010936:Plant Extracts / Q000737:chemistry; D012097:Repressor Proteins / Q000494:pharmacology; D013729:Terpenes / Q000737:chemistry / Q000494:pharmacology*; D014158:Transcription, Genetic / Q000187:drug effects*
D004791:Enzyme Inhibitors; D010936:Plant Extracts; D012097:Repressor Proteins; D013729:Terpenes; D000123:Acetyltransferases; D051548:Histone Acetyltransferases; C054597:garcinol