Kim YK, Han JW, Woo YN, Chun JK, Yoo JY, Cho EJ, Hong S, Lee HY, Lee YW, Lee HW. Expression of p21(WAF1/Cip1) through Sp1 sites by histone deacetylase inhibitor apicidin requires PI 3-kinase-PKC epsilon signaling pathway.
Oncogene 2003;
22:6023-31. [PMID:
12955081 DOI:
10.1038/sj.onc.1206875]
[Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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.
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