Journal Article

Group 3 medulloblastoma transcriptional networks collapse under domain specific EP300/CBP inhibition

Delahunty, Ian M., Khashana, Yousef, Roth, Jennifer A., Mercier, Audrey, Nance, Stephanie, Kocak, Mustafa, Durbin, Adam D., Roussel, Martine F., Goel, Vanshita, Abraham, Brian J., Shendy, Noha A. M., Liu, Qi, Wang, Yingzhe, Zhang, Yang, Freeman, Burgess B., Ronan, Melissa A., Rees, Matthew G., Orr, Brent A., Qi, Jun, Sigua, Logan H., Schonbrunn, Ernst, Robinson, Sarah, Bikowitz, Melissa, Wang, Tingjian

2024

Overview

Chemical discovery efforts commonly target individual protein domains. Many proteins, including the EP300/CBP histone acetyltransferases (HATs), contain several targetable domains. EP300/CBP are critical gene-regulatory targets in cancer, with existing high potency inhibitors of either the catalytic HAT domain or protein-binding bromodomain (BRD). A domain-specific inhibitory approach to multidomain-containing proteins may identify exceptional-responding tumor types, thereby expanding a therapeutic index. Here, we discover that targeting EP300/CBP using the domain-specific inhibitors, A485 (HAT) or CCS1477 (BRD) have different effects in select tumor types. Group 3 medulloblastoma (G3MB) cells are especially sensitive to BRD, compared with HAT inhibition. Structurally, these effects are mediated by the difluorophenyl group in the catalytic core of CCS1477. Mechanistically, bromodomain inhibition causes rapid disruption of genetic dependency networks that are required for G3MB growth. These studies provide a domain-specific structural foundation for drug discovery efforts targeting EP300/CBP and identify a selective role for the EP300/CBP bromodomain in maintaining genetic dependency networks in G3MB. The differential effects of targeting individual domains of multidomain enzymatic proteins are generally poorly understood. Here, the authors demonstrate lineage-specific sensitivities to domain-specific inhibition of EP300/CBP proteins across cancer and link these effects in group 3 medulloblastoma to control of a transcriptional dependency network.

• Publisher: Nature Publishing Group UK,Nature Publishing Group,Nature Portfolio
• Subject: 13 / 13/106 / 14 / 38/39 / 49 / 49/47 / 631/154/309/2420 / 631/535/1266 / 631/67/1059/153 / 631/67/1922 / 631/92/360 / 64 / 64/60 / 82/103 / 82/16 / Animals / Antineoplastic Agents - pharmacology / Cancer / Cell Line, Tumor / Cerebellar Neoplasms - drug therapy / Cerebellar Neoplasms - genetics / Cerebellar Neoplasms - metabolism / Cerebellar Neoplasms - pathology / E1A-Associated p300 Protein - antagonists & inhibitors / E1A-Associated p300 Protein - genetics / E1A-Associated p300 Protein - metabolism / Gene Expression Regulation, Neoplastic - drug effects / Gene regulation / Gene Regulatory Networks - drug effects / Histones / Humanities and Social Sciences / Humans / Inhibitors / Medulloblastoma / Medulloblastoma - drug therapy / Medulloblastoma - genetics / Medulloblastoma - metabolism / Medulloblastoma - pathology / Mice / multidisciplinary / Networks / Outerwear / Protein Domains / Proteins / Science / Science (multidisciplinary) / Tumors