Abstract A29: Targeting p300 addiction in CBP-deficient cancers causes synthetic lethality by apoptotic cell death due to abrogation of MYC expression

Loss-of-function mutations in the CBP/CREBBP gene, which encodes a histone acetyltransferase (HAT), are present in a variety of human tumors, including lung, bladder, gastric, and hematopoietic cancers. Consequently, development of a molecular targeting method capable of specifically killing CBP-deficient cancer cells would greatly improve cancer therapy. Functional screening of synthetic-lethal genes in CBP-deficient cancers identified the CBP paralog p300/EP300. Ablation of p300 in CBP-knockout and -deficient cancer cells induced G1/S cell-cycle arrest, followed by apoptosis. Genome-wide gene expression analysis revealed that MYC is a major factor responsible for the synthetic lethality. Indeed, p300 ablation in CBP-deficient cells caused downregulation of MYC expression via reduction of histone acetylation in its promoter, and this lethality was rescued by exogenous MYC expression. The p300-HAT inhibitor C646 specifically suppressed the growth of CBP-deficient lung and hematopoietic cancer cells in vitro and in vivo; thus p300 is a promising therapeutic target for treatment of CBP-deficient cancers.Citation Format: Hideaki Ogiwara, Mariko Sasaki, Takahiro Oike, Saito Higuchi, Yuichi Tominaga, Takashi Kohno. Targeting p300 addiction in CBP-deficient cancers causes synthetic lethality by apoptotic cell death due to abrogation of MYC expression [abstract]. In: Proceedings of the AACR Precision Medicine Series: Opportunities and Challenges of Exploiting Synthetic Lethality in ...
Source: Molecular Cancer Therapeutics - Category: Cancer & Oncology Authors: Tags: Finding Synthetic Lethal Interactions through Functional Genomics: Poster Presentations - Proffered Abstracts Source Type: research