Abstract
CRISPR/dCas9 systems can precisely control endogenous gene expression without interrupting host genomic sequence and have provided a novel and feasible strategy for the treatment of cancers at the transcriptional level. However, development of CRISPR/dCas9-based anti-cancer therapeutics remains challenging due to the conflicting requirements for the design of the delivery system: a cationic and membrane-binding surface facilitates the tumor accumulation and cellular uptake of the CRISPR/dCas9 system, but hinders the circulating stability in vivo. Here, a multistage delivery nanoparticle (MDNP) that can achieve tumor-targeted delivery of CRISPR/dCas9 systems and restore endogenous microRNA (miRNA) expression in vivo is described. MDNP is designed as a core-shell structure in which the shell is made of a responsive polymer that endows MDNP with the capability to present different surface properties in response to its surrounding microenvironment, allowing the MNDP overcoming multiple physiological barriers and delivering the payload to tumor tissues with an optimal efficiency. Systemic administration of MDNP/dCas9-miR-524 to tumor-bearing mice achieved effective upregulation of miR-524 in tumors, leading to the simultaneous interferences of multiple signal pathways related to cancer cell proliferation and presenting remarkable tumor growth retardation, suggesting the feasibility of utilizing MDNP to achieve tumor-targeting delivery of CRISPR/dCas9 with sufficient levels to realize its therapeutic effects.