Abstract 4712: Target epigenetic regulation at a specific genomic region by using DNA binding molecules and HDACi

Abstract

Abstract Pyrrole-Imidazole (PI) polyamide molecule was originally designed from structures of natural DNA binding molecule, such as Distamicine and Diocarbamicine and has been recognized as a synthetic molecule which binds the minor groove of Watson-Click base pair of double-stranded DNA in a sequence-dependent manner. We hypothesized conjugates between this synthetic DNA binding molecule and Histone Deacetylase inhibitor (HDACi) of Suberoylanilide hydroxamic acid (SAHA) should regulate histone acetylation in a specific region of the genome. We have taken two strategies to confirm this hypothesis. One is the candidate gene approach and another is chemical library approach. We synthesized a PI polyamide targeted the p16INK4a tumor suppressor gene and also synthesized a library of sequence-specific PI polyamides conjugated with the potent HDAC inhibitor, termed PIP-SAHA and screened their effect on the expression of tumor suppressor genes and Yamanaka factors, respectively. Chromatin immunoprecipitation analysis revealed SAHA-PIP induce acetylation of Histone H4 and H3 in the promoter region of p16, Oct-4 and Nanog. SAHA-PIP showed significant induction against c-Myc, Oct-3/4, Sox-2, and Klf-4, respectively in MEF but did not show significant induction of tumor suppressor p16 transcription. We also confirmed only SAHA did not show such histon acetylation and transcription induction, which implicated the role of PI polyamide conjugates in the induction of histone acetylation in specific genomic regions. Furthermore, a significant change in MEF morphology was demonstrated with our hit SAHA-PIPs. Those data suggests that a capability of PIP-SAHA regulate histone modification in a genomic sequence specific manner and promote agents for reprogramming efficiency in order to generate iPSCs, although the endogenous tumor suppressor gene expression was not observed, probably by means of “double lock” epigenetic silencing of tumor suppressor gene. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4712. doi:1538-7445.AM2012-4712