Targeted transcriptional downregulation of MYC using epigenomic controllers demonstrates antitumor activity in hepatocellular carcinoma models
William Senapedis, Kayleigh Gallagher, Elmer Figueroa, Jeremiah D. Farelli, Robert Lyng, John Hodgson, Charles W. O’Donnell, Joseph V Newman, Madison Pacaro, Stephen K. Siecinski, Justin Chen, Thomas McCauley
Abstract
Dysregulation of master regulator c-MYC (MYC) plays a central role in hepatocellular carcinoma (HCC) and other cancers but remains an elusive target for therapeutic intervention. MYC expression is epigenetically modulated within naturally occurring DNA loop structures, Insulated Genomic Domains (IGDs). We present a therapeutic approach using an epigenomic controller (EC), a programmable epigenomic mRNA medicine, to precisely modify MYC IGD sub-elements, leading to methylation of MYC regulatory elements and durable downregulation of MYC mRNA transcription. Significant antitumor activity is observed in preclinical models of HCC treated with the MYC-targeted EC, as monotherapy or in combination with tyrosine kinase or immune checkpoint inhibitors. These findings pave the way for clinical development of MYC-targeting epigenomic controllers in HCC patients and provide a framework for programmable epigenomic mRNA therapeutics for cancer and other diseases. Development of targeted MYC inhibitors for cancer therapy remains challenging. Here, the authors design an mRNA medicine which downregulates MYC gene transcription via epigenetic modification of MYC regulatory elements, showing significant antitumor activity in preclinical models of hepatocellular carcinoma.