Redox-responsive Nanoplatform Research Articles

Multifunctional Redox-Responsive Nanoplatform with Dual Activation of Macrophages and T Cells for Antitumor Immunotherapy.

High expression of programmed death ligand 1 (PD-L1) and strong immune evasion ability of the tumor microenvironment (TME) are maintained through mutual regulation between different immune and stromal cells, which causes obstructions for cancer immunotherapy, especially immunosuppressive M2-like phenotype tumor-associated macrophages (TAMs). Repolarization of TAMs to the M1-like phenotype could secrete proinflammatory cytokines and reverse the immunosuppressive state of the TME. However, we found that reactive oxygen species (ROS) generated by repolarized TAMs could be a double-edged sword: ROS cause a stronger suppressive effect on CD8 T cells through an increased proportion of apoptotic regulatory T (Treg) cells. Thus, simply repolarizing TAMs while ignoring the suppressed function of T cells is insufficient for generating adequate antitumor immunity. Accordingly, we engineered multifunctional redox-responsive nanoplatform NPs (M+C+siPD-L1) with Toll-like receptor agonist (M), catalase (C), and siPD-L1 encased for coregulation of both TAMs and T cells to maximize cancer immunotherapy. Our results demonstrated that NPs (M+C+siPD-L1) showed superior biocompatibility and intratumor accumulation. For in vitro experiments, NPs (M+C+siPD-L1) simultaneously repolarized TAMs to the M1-like phenotype, hydrolyzed extra ROS, knocked down the expression of PD-L1 on tumor cells, and rescued the function of CD8 T cells suppressed by Treg cells. In both orthotopic Hepa1-6 and 4T1 tumor-bearing mouse models, NPs (M+C+siPD-L1) could effectively evoke active systemic antitumor immunity and inhibit tumor growth. The combination of repolarizing TAMs, hydrolyzing extra ROS, and knocking down the expression of PD-L1 proves to be a synergistic approach in cancer immunotherapy.

Biomimetic redox-responsive prodrug micelles with diselenide linkage for platinum nanozymes augmented sonodynamic/chemo combined therapy of colon cancer

Due to the complexity of tumorigenesis, it is hard to completely cure tumors with a single tumor therapy. Combined sonodynamic therapy and chemotherapy (sono-chemotherapy) based on the stimulus-responsive nano-delivery system is a prospective antitumor strategy that has demonstrated synergistic treatment effects and higher treatment effects than any monotherapy. The multiple diselenide linkages-contained DSeDP-alt-PEG conjugated with Ce6/PTX to yield prodrugs DC and DP micelles, and platinum nanozymes that possessed multiple enzyme activities were loaded in DC to form stable micelles (DC@Pt). The nanomicelles were modified with the homologous tumor cell membrane (DPC@Pt@M) to generate a REDOX-responsive bionic nanoplatform to realize the sono-chemotherapy combined treatment for colon cancer. As a redox-responsive nanoplatform, DPC@Pt@M exhibited excellent water solubility and bioavailability, and good targeting ability both in vitro and in vivo to realize the controlled release of Ce6 and PTX at the tumor site. Pt nanozymes acted as a cascade catalyst (SOD-CAT, SOD-POD) to alleviate hypoxia and improve SDT. Under ultrasonic irradiation, the novel micelle DPC@Pt@M increased ROS production and induced apoptosis efficiently in vitro and in vivo to improve sono-chemotherapeutic efficiency for colon cancer. Therefore, sonodynamic/chemo therapies demonstrated a clear synergistic effect, and this research is expected to provide a paradigm of combination therapy strategies for colon cancer.

Redox-responsive nanoplatform for codelivery of miR-519c and gemcitabine for pancreatic cancer therapy.

Desmoplastic and hypoxic pancreatic cancer microenvironment induces aberrant expression of miRNAs and hypoxia-inducible factor-1α (HIF-1α) responsible for gemcitabine (GEM) resistance. We demonstrated that miR-519c was down-regulated in pancreatic cancer and transfection of miR-519c in GEM-resistant pancreatic cancer cells inhibited HIF-1α level under hypoxia. We synthesized redox-sensitive mPEG-co-P(Asp)-g-DC-g-S-S-GEM polymer, with GEM payload of 14% (w/w) and 90% GEM release upon incubation with l-glutathione. We synthesized mPEG-co-P(Asp)-g-TEPA-g-DC for complex formation with miRNA. Chemical modification of miR-519c with 2'-O-methyl phosphorothioate (OMe-PS) at 3' end enhanced its stability and activity without being immunogenic. Epidermal growth factor receptor targeting peptide GE11 decoration increased tumor accumulation of micelles after systemic administration and significantly inhibited orthotopic desmoplastic pancreatic cancer growth in NSG mice by down-regulating HIF-1α and genes responsible for glucose uptake and cancer cell metabolism. Our multifunctional nanomedicine of GEM and OMe-PS-miR-519c offers a novel therapeutic strategy to treat desmoplasia and hypoxia-induced chemoresistance in pancreatic cancer.

Hyaluronic acid reduction-sensitive polymeric micelles achieving co-delivery of tumor-targeting paclitaxel/apatinib effectively reverse cancer multidrug resistance

Multidrug resistance (MDR) of cancer cells is a significant challenge in chemotherapy, highlighting the urgent medical need for simple and reproducible strategies to reverse this process. Here, we report the development of an active tumor-targeting and redox-responsive nanoplatform (PA-ss-NP) using hyaluronic acid-g-cystamine dihydrochloride-poly-ε-(benzyloxycarbonyl)-L-lysine (HA-ss-PLLZ) to co-deliver paclitaxel (PTX) and apatinib (APA) for effective reversal of MDR. This smart nanoplatform specifically bound to CD44 receptors, leading to selective accumulation at the tumor site and uptake by MCF-7/ADR cells. Under high concentrations of cellular glutathione (GSH), the nanocarrier was degraded rapidly with complete release of its encapsulated drugs. Released APA effectively inhibited the function of the P-glycoprotein (P-gp) drug pump and improved the sensitivity of MDR cells to chemotherapeutic agents, leading to the recovery of PTX chemosensitivity in MDR cells. As expected, this newly developed intelligent drug delivery system could effectively control MDR, both in vitro and in vivo.

Redox-responsive diphenylalanine aggregate mediated by cyclodextrin

The molecular assembling properties can be dramatically improved using redox-responsive nanoplatforms, which can bring quite different aggregation modes and binding behaviors in the redox states. In this work, we fabricated a redox-responsive system based on the host–guest complexation of β-cyclodextrin (β-CD) with ferrocene-modified diphenylalanine (Fc-FF). The morphological conversion of Fc-FF can be easily achieved from nanofibers to nanospheres in the presence of β-CD, and the supramolecular nanospheres can be reversibly assembled and disassembled by the chemical redox of ferrocenyl groups in the Fc-FF⊂β-CD nanoassemblies. These results demonstrate that the incorporation of stimuli-switchable components with macrocyclic receptors may become a promising approach to the construction of smart peptide-involved supramolecular assemblies.

Redox-responsive theranostic nanoplatforms based on inorganic nanomaterials

Spurred on by advances in materials chemistry and nanotechnology, scientists have developed many novel nanopreparations for cancer diagnosis and therapy. To treat complex malignant tumors effectively, multifunctional nanomedicines with targeting ability, imaging properties and controlled drug release behavior should be designed and exploited. The therapeutic efficiency of loaded drugs can be dramatically improved using redox-responsive nanoplatforms which can sense the differences in the redox status of tumor tissues and healthy ones. Redox-sensitive nanocarriers can be constructed from both organic and inorganic nanomaterials; however, at present, drug delivery nanovectors progressively lean towards inorganic nanomaterials because of their facile synthesis/modification and their unique physicochemical properties. In this review, we focus specifically on the preparation and application of redox-sensitive nanosystems based on mesoporous silica nanoparticles (MSNs), carbon nanomaterials, magnetic nanoparticles, gold nanomaterials and other inorganic nanomaterials. We discuss relevant examples of redox-sensitive nanosystems in each category. Finally, we discuss current challenges and future strategies from the aspect of material design and practical application.

Visible light-induced crosslinking and physiological stabilization of diselenide-rich nanoparticles for redox-responsive drug release and combination chemotherapy.

Undesired physiological instability of nanocarriers and premature drug leakage during blood circulation result in compromised therapeutic efficacy and severe side effects, which have significantly impeded the development of nanomedicine. Facile crosslinking of drug-loaded nanocarriers while keeping the potency of site-specific degradation and drug release has emerged as a viable strategy to overcome these drawbacks. Additionally, combination therapy has already shown advantages in inhibiting advanced tumors and life extension than single drug therapy. Herein, three kinds of diselenide-rich polymers were fabricated with distinct hydrophobic side chains. The component effect was interrogated to screen out PEG-b-PBSe diblock copolymer due to its favorable self-assembly controllability and high drug loading of camptothecin (CPT) and doxorubicin (DOX) that had synergistic antitumor property. Facile visible light-induced diselenide metathesis and regeneration was employed to crosslink nanocarriers for the first time. The dual drug-loaded crosslinked micelles (CPT/DOX-CCM) were stable in physiological conditions with minimal drug leakage, possessing extended blood circulation, whereas hand-in-hand dual drug release was significantly accelerated in tumor's redox microenvironments. Invitro cytotoxicity evaluation and invivo tumor suppression with low dosage drugs further demonstrated the favorable potency of the redox-responsive nanoplatform in tumor combination chemotherapy.