title: Expression of p21(WAF1/Cip1) through Sp1 sites by histone deacetylase inhibitor apicidin requires PI 3-kinase-PKC epsilon signaling pathway.
abstract: We previously reported that the activation of p21(WAF1/Cip1) transcription by histone deacetylase inhibitor apicidin was mediated through Sp1 sites and pointed to the possible participation of protein kinase C (PKC). In this study, we investigated the role and identity of the specific isoforms of PKC involved and identified phosphatidylinositol 3-kinase (PI 3-kinase) as an upstream effector in HeLa cells. Using an isoform-specific pharmacological inhibitor of PKC, a PKC epsilon dominant-negative mutant, and antisense oligonucleotide to inhibit PKC epsilon specifically, we found that among PKC isoforms, PKC epsilon was required for the p21(WAF1/Cip1) expression by apicidin. In addition to PKC epsilon, PI 3-kinase appeared to participate in the activation of p21(WAF1/Cip1) promoter by apicidin, since inactivation of PI 3-kinase either by transient expression of dominant-negative mutant of PI 3-kinase or its specific inhibitors, LY294002 and wortmannin, attenuated the activation of p21(WAF1/Cip1) promoter and p21(WAF1/Cip1) protein expression by apicidin. Furthermore, membrane translocation of PKC epsilon in response to apicidin was blocked by the PI 3-kinase inhibitor, indicating the role of PI 3-kinase as an upstream molecule of PKC epsilon in the p21(WAF1/Cip1) promoter activation by apicidin. However, the p21(WAF1/Cip1) expression by apicidin appeared to be independent of the histone hyperacetylation, since apicidin-induced histone hyperacetylation of p21(WAF1/Cip1) promoter region was not affected by inhibition of PI 3-kinase and PKC, suggesting that the chromatin remodeling through the histone hyperacetylation alone might not be sufficient for the expression of p21(WAF1/Cip1) by apicidin. Taken together, these results suggest that the PI 3-kinase-PKC epsilon signaling pathway plays a pivotal role in the expression of the p21(WAF1/Cip1) by apicidin.
authors.affiliation: Department of Biochemistry and Molecular Biology, College of Pharmacy, Sungkyunkwan University, Suwon 440-746, Korea.
authors.forename: Yong Kee
authors.initials: YK
authors.lastname: Kim
authors.forename: Jeung-Whan
authors.initials: JW
authors.lastname: Han
authors.forename: Yun Na
authors.initials: YN
authors.lastname: Woo
authors.forename: Jae Kwang
authors.initials: JK
authors.lastname: Chun
authors.forename: Ji Yeon
authors.initials: JY
authors.lastname: Yoo
authors.forename: Eun-Jung
authors.initials: EJ
authors.lastname: Cho
authors.forename: Sungyoul
authors.initials: S
authors.lastname: Hong
authors.forename: Hoi Young
authors.initials: HY
authors.lastname: Lee
authors.forename: Yin-Won
authors.initials: YW
authors.lastname: Lee
authors.forename: Hyang-Woo
authors.initials: HW
authors.lastname: Lee
mesh_terms: D000107:Acetylation / Q000187:drug effects; D001665:Binding Sites; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000096:biosynthesis / Q000187:drug effects / Q000235:genetics*; D004791:Enzyme Inhibitors / Q000378:metabolism / Q000494:pharmacology*; D015870:Gene Expression / Q000187:drug effects; D006367:HeLa Cells; D056572:Histone Deacetylase Inhibitors; D006801:Humans; D010456:Peptides, Cyclic / Q000378:metabolism / Q000494:pharmacology*; D019869:Phosphatidylinositol 3-Kinases / Q000187:drug effects / Q000378:metabolism*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D008926:Plicamycin / Q000494:pharmacology; D011401:Promoter Regions, Genetic; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000187:drug effects / Q000378:metabolism*; D051744:Protein Kinase C-epsilon; D015398:Signal Transduction / Q000187:drug effects; D016329:Sp1 Transcription Factor / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D004791:Enzyme Inhibitors; D056572:Histone Deacetylase Inhibitors; D010456:Peptides, Cyclic; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D008926:Plicamycin; D011493:Protein Kinase C; D051744:Protein Kinase C-epsilon; D016329:Sp1 Transcription Factor; C493956:CDKN1A protein, human; C102351:apicidin; C497255:PRKCE protein, human