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.

The clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR‐associated (Cas) enzyme, Cas13a, holds great promise in cancer treatment due to its potential for selective destruction of tumor cells via collateral effects after target recognition. However, these collateral effects do not specifically target tumor cells and may cause safety issues when administered systemically. Herein, a dual‐locking nanoparticle (DLNP) that can restrict CRISPR/Cas13a activation to tumor tissues is described. DLNP has a core–shell structure, in which the CRISPR/Cas13a system (plasmid DNA, pDNA) is encapsulated inside the core with a dual‐responsive polymer layer. This polymer layer endows the DLNP with enhanced stability during blood circulation or in normal tissues and facilitates cellular internalization of the CRISPR/Cas13a system and activation of gene editing upon entry into tumor tissue. After carefully screening and optimizing the CRISPR RNA (crRNA) sequence that targets programmed death‐ligand 1 (PD‐L1), DLNP demonstrates the effective activation of T‐cell‐mediated antitumor immunity and the reshaping of immunosuppressive tumor microenvironment (TME) in B16F10‐bearing mice, resulting in significantly enhanced antitumor effect and improved survival rate. Further development by replacing the specific crRNA of target genes can potentially make DLNP a universal platform for the rapid development of safe and efficient cancer immunotherapies.

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Current cancer immunotherapies including chimeric antigen receptor (CAR)-based therapies and checkpoint immune inhibitors have demonstrated significant clinical success, but always suffer from immunotoxicity and autoimmune disease. Recently, nanomaterial-based immunotherapies are developed to precisely control in vivo immune activation in tumor tissues for reducing immune-related adverse events. However, little consideration has been put on the spatial modulation of interactions between immune cells and cancer cells to optimize the efficacy of cancer immunotherapies. Herein, a rational design of immunomodulating nanoparticles is demonstrated that can in situ modify the tumor cell surface with natural killer cell (NK cell)-activating signals to achieve in situ activation of tumorinfiltrating NK cells, as well as direction of their antitumor immunity toward tumor cells.Using these immunomodulating nanoparticles, the remarkable inhibition of tumor growth is observed in mice without noticeable side effects. This study provides an accurate immunomodulation strategy that achieves safe and effective antitumor immunity through in situ NK cell activation in tumors. Further development by constructing interactions with various immune cells can potentially make this nanotechnology become a general platform for the design of advanced immunotherapies for cancer treatments.

Acute myocardial infarction (MI) is the leading cause of death worldwide. Exogenous delivery of nitric oxide (NO) to the infarcted myocardium has proven to be an effective strategy for treating MI due to the multiple physiological functions of NO. However, reperfusion of blood flow to the ischemic tissues is accompanied by the overproduction of toxic reactive oxygen species (ROS), which can further exacerbate tissue damage and compromise the therapeutic efficacy. Here, an injectable hydrogel is synthesized from the chitosan modified by boronate-protected diazeniumdiolate (CS-B-NO) that can release NO in response to ROS stimulation and thereby modulate ROS/NO disequilibrium after ischemia/reperfusion (I/R) injury. Furthermore, administration of CS-B-NO efficiently attenuated cardiac damage and adverse cardiac remodeling, promoted repair of the heart, and ameliorated cardiac function, unlike a hydrogel that only released NO, in a mouse model of myocardial I/R injury. Mechanistically, regulation of the ROS/NO balance activated the antioxidant defense system and protected against oxidative stress induced by I/R injury via adaptive regulation of the Nrf2-Keap1 pathway. Inflammation is then reduced by inhibition of the activation of NF-𝜿B signaling. Collectively, these results show that this dual-function hydrogel may be a promising candidate for the protection of tissues and organs after I/R injury.