Requirement of PI3K-PKC$\varepsilon$ Signaling Pathway for Apicidin Induction of p$21^{WAFl/Cip1}$

We previously reported that the activation of p$21^{WAFl/Cip1}$ transcription by histone deacetylase inhibitor apicidin was mediated through Spl 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$\varepsilon$ dominant-negative mutant, and antisense oligonucleotide to inhibit PKC$\varepsilon$ specifically, (omitted)