Suppression of adaptive responses to targeted cancer therapy by transcriptional repression [ChIP-seq]

Large-scale genomic profiling efforts have facilitated the characterization of molecular alterations in cancers and aided the development of targeted kinase inhibitors for a wide array of cancer types. However, resistance to these targeted therapies invariably develops and limits their clinical efficacy. Targeting tumours with kinase inhibitors induces complex adaptive survival programs that promote the persistence of a fraction of the original cancer cell population, facilitating the eventual outgrowth of inhibitor-resistant tumour clones following clonal evolution. Here we show that the addition of a newly identified transcriptional repressor, THZ1, to targeted cancer therapy enhances cell killing and impedes the emergence of drug-resistant cell populations in cellular and in vivo cancer models with diverse genetic dependencies. We propose that targeted therapy induces a state of transcriptional dependency in a subpopulation of cells poised to become drug tolerant. THZ1 can exploit this dependency by blocking dynamic transcriptional responses, remodelling of enhancers and key signalling outputs required for tumour cell survival in the setting of targeted cancer therapies. These findings suggest that the addition of THZ1 to targeted cancer therapies is a promising broad-based strategy to hinder the emergence of drug-resistant cancer cell populations. ChIP-Seq for enhancer-binding proteins in multiple tumor cell lines