Abstract 519: Targeting MYC as a novel therapeutic strategy for an epigenetic-driven cancer: NUT Carcinoma

Abstract

Abstract Epigenetic dysregulation is widespread in cancer, playing a pivotal role in shaping cell function and contributing to the process of oncogenic transformation. NUT Carcinoma (NC) is an exceptionally rare and aggressive cancer lacking effective treatment, with a dismal prognosis - NC patients typically survive less than seven months after the initial diagnosis. NC is characterized by the presence of chromosomal rearrangements involving the gene encoding for the testis-specific NUT protein and a ubiquitous gene encoding an epigenetic regulator, BRD4 in most cases. Previous studies have demonstrated the role of the BRD4-NUT fusion protein in generating clusters of acetylated histones, namely “megadomains,” throughout NC cell chromatin. These NUT-containing fusion proteins are involved in NC oncogenesis by altering the epigenetic and transcriptional landscapes, promoting cell proliferation while impeding cell differentiation. Indeed, several downstream targets, including P63, SOX2, and MYC, have been identified to be modulated by NUT fusion proteins, independently of the fusion partners. This study focuses on a novel therapeutic approach targeting MYC for NC treatment. We conducted a comprehensive preclinical study of OMO-103, a MYC inhibitor currently undergoing clinical evaluation, using various NC patient-derived cell lines. Through cell viability assays, cell cytometry, western blotting, RNA-seq data analysis in vitro, as well as in vivo drug efficacy evaluation in NC xenografts, we delved into the effects of OMO-103 on NC cells. Our findings reveal that OMO-103 effectively inhibits NC cell growth both in vitro and in vivo. It induces cell apoptosis, differentiation, and cell cycle arrest in vitro, and when tested in xenografts in vivo, OMO-103 reduces tumor growth and enhances mouse survival, particularly when combined with a chemotherapy regimen. This study presents a promising therapeutic strategy for an incurable and aggressive cancer type. Citation Format: Carmen Escudero-Iriarte, Joel Castro, Iker Beniavides-Puy, Natalia S. Tissera, Jessica Querol-Paños, Irene Agustí, Jonathan R. Whitfield, Maria Vieito, Lara Nonell, Teresa Macarulla, Irene Braña, Laura Soucek, Tian V. Tian. Targeting MYC as a novel therapeutic strategy for an epigenetic-driven cancer: NUT Carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 519.