Tumour suppression by targeted intravenous non-viral CRISPRa using dendritic polymers

Abstract

Aberrant gene expression is a hallmark of cancer. Although transcription is traditionally considered 'undruggable', the development of CRISPR-associated protein 9 (Cas9) systems offers enormous potential to rectify cancer-associated transcriptional abnormalities in malignant cells. However delivery of this technology presents a critical challenge to overcome in order to realize clinical translation for cancer therapy. In this article we demonstrate for the first time, a fully synthetic strategy to enable CRISPR-mediated activation (CRISPRa) of tumour suppressor genes <i>in vivo</i> using a targeted intravenous approach. We show this <i>via</i> highly efficient transcriptional activation of two model tumour suppressor genes, Mammary Serine Protease Inhibitor (MASPIN, <i>SERPINB5</i>) and cysteine-rich 61/connective tissue growth factor/nephroblastoma-overexpressed 6 (<i>CCN6</i>, <i>WISP3</i>), in a mouse model of breast cancer. In particular, we demonstrate that targeted intravenous delivery of can be achieved using a novel nanoscale dendritic macromolecular delivery agent, with negligible toxicity and long lasting therapeutic effects, outlining a targeted effective formulation with potential to treat aggressive malignancies.