Amino acid-based metallo-supramolecular nanoassemblies capable of regulating cellular redox homeostasis for tumoricidal chemo-/photo-/catalytic combination therapy.

Nanozymes, as nanomaterials with natural enzyme activities, have been widely applied to deliver various therapeutic agents to synergistically combat the progression of malignant tumors. However, currently common inorganic nanozyme-based drug delivery systems still face challenges such as suboptimal biosafety, inadequate stability, and inferior tumor selectivity. Herein, a super-stable amino acid-based metallo-supramolecular nanoassembly (FPIC NPs) with peroxidase (POD)- and glutathione oxidase (GSHOx)-like activities was fabricated via Pt4+-driven coordination co-assembly of l-cysteine derivatives, the chemotherapeutic drug curcumin (Cur), and the photosensitizer indocyanine green (ICG). The superior POD- and GSHOx-like activities could not only catalyze the decomposition of endogenous hydrogen peroxide into massive hydroxyl radicals, but also deplete the overproduced glutathione (GSH) in cancer cells to weaken intracellular antioxidant defenses. Meanwhile, FPIC NPs would undergo degradation in response to GSH to specifically release Cur, causing efficient mitochondrial damage. In addition, FPIC NPs intrinsically enable fluorescence/photoacoustic imaging to visualize tumor accumulation of encapsulated ICG in real time, thereby determining an appropriate treatment time point for tumoricidal photothermal (PTT)/photodynamic therapy (PDT). In vitro and in vivo findings demonstrated the quadruple orchestration of catalytic therapy, chemotherapeutics, PTT, and PDT offers conspicuous antineoplastic effects with minimal side reactions. This work may provide novel ideas for designing supramolecular nanoassemblies with multiple enzymatic activities and therapeutic functions, allowing for wider applications of nanozymes and nanoassemblies in biomedicine.

Self-recognizing and stimulus-responsive carrier-free metal-coordinated nanotheranostics for magnetic resonance/photoacoustic/fluorescence imaging-guided synergistic photo-chemotherapy.

Carrier-free nanotheranostics directly assembled by using clinically used photosensitizers and chemotherapeutic drugs are a promising alternative to tumor theranostics. However, the weak interaction-driven assembly still suffers from low structural stability against disintegration, lack of targeting specificity, and poor stimulus-responsive property. Moreover, almost all exogenous ligands possess no therapeutic effect. Enlightened by the concept of metal-organic frameworks, we developed a novel self-recognizing metal-coordinated nanotheranostic agent by the coordination-driven co-assembly of photosensitizer indocyanine green (ICG) and chemo-drug methotrexate (MTX, also served as a specific "targeting ligand" towards folate receptors), in which ferric (FeIII) ions acted as a bridge to tightly associate ICG with MTX. Such carrier-free metal-coordinated nanotheranostics with high dual-drug payload (∼94 wt%) not only possessed excellent structural and physiological stability, but also exhibited prolonged blood circulation. In addition, the nanotheranostics could achieve the targeted on-demand drug release by both stimuli of internal lysosomal acidity and external near-infrared laser. More importantly, the nanotheranostics could self-recognize the cancer cells and selectively target the tumors, and therefore they decreased toxicity to normal tissues and organs. Consequently, the nanotheranostics showed strongly synergistic potency for tumor photo-chemotherapy under the precise guidance of magnetic resonance/photoacoustic/fluorescence imaging, thereby achieving highly effective tumor curing efficiency. Considering that ICG and bi-functional MTX are approved by the Food and Drug Administration, and FeIII ions have high biosafety, the self-recognizing and stimulus-responsive carrier-free metal-coordinated nanotheranostics may hold potential applications in tumor theranostics.

Light/pH-Triggered Biomimetic Red Blood Cell Membranes Camouflaged Small Molecular Drug Assemblies for Imaging-Guided Combinational Chemo-Photothermal Therapy.

Nanoparticles camouflaged by red blood cell (RBC) membranes have attracted considerable attention owing to reservation of structure of membrane and surface proteins, endowing prominent cell-specific function including biocompatibility, prolonged circulation lifetime, and reduced reticular endothelial system (RES) uptake ability. Considering the drawbacks of carrier-free nanomedicine including the serious drug burst release, poor stability, and lack of immune escape function, herein we developed and fabricated a novel RBC membranes biomimetic combinational therapeutic system by enveloping the small molecular drug coassemblies of 10-hydroxycamptothecin (10-HCPT) and indocyanine green (ICG) in the RBC membranes for prolonged circulation, controlled drug release, and synergistic chemo-photothermal therapy (PTT). The self-reorganized RBCs@ICG-HCPT nanoparticles (NPs) exhibited a diameter of ∼150 nm with core-shell structure, high drug payload (∼92 wt %), and reduced RES uptake function. Taking advantage of the stealth functionality of RBC membranes, RBCs@ICG-HCPT NPs remarkably enhanced the accumulation at the tumor sites by passive targeting followed by cellular endocytosis. Upon the stimuli of near-infrared laser followed by acidic stimulation, RBCs@ICG-HCPT NPs showed exceptional instability by heat-mediated membrane disruption and pH change, thereby triggering the rapid disassembly and accelerated drug release. Consequently, compared with individual treatment, RBCs@ICG-HCPT NPs under dual-stimuli accomplished highly efficient apoptosis in cancer cells and remarkable ablation of tumors by chemo-PTT. This biomimetic nanoplatform based on carrier-free, small molecular drug coassemblies integrating imaging capacity as a promising theranostic system provides potential for cancer diagnosis and combinational therapy.

Improved Stable Indocyanine Green (ICG)-Mediated Cancer Optotheranostics with Naturalized Hepatitis B Core Particles.

In recent years, hepatitis B core protein virus-like particle (HBc VLP) is an impressive biomaterial, which has attracted considerable attention due to favorable properties such as structural stability, high uptake efficiency, and biocompatibility in biomedical applications. Heretofore, only a few attempts have been made to apply it in physical, chemical, and biological therapy for cancer. In this study, a tumor-targeting RGD-HBc VLP is first fabricated through genetic engineering. For image-guided cancer phototherapy, indocyanine green (ICG) is loaded into RGD-HBc VLP via a disassembly/reassembly pathway and electrostatic attraction with high efficiency. The self-assembled stable RGD-HBc VLP significantly improves body retention (fourfold longer), aqueous stability, and target specificity of ICG. Remarkably, these positive reformations promote more accurate and sensitive imaging of U87MG tumor, as well as prolonged tumor destruction in comparison with free ICG. Moreover, the photothermal and photodynamic effect on tumors are quantitatively differentiated by multiple linear regression analysis. Overall, less-potent medicinal ICG can be perfectly rescued by bioengineered HBc VLP to realize enhanced cancer optotheranostics.

Construction of Multifunctional Fe3O4-MTX@HBc Nanoparticles for MR Imaging and Photothermal Therapy/Chemotherapy.

To accomplish effective cancer imaging and integrated therapy, the multifunctional nanotheranostic Fe3O4-MTX@HBc core-shell nanoparticles (NPs) were designed. A straightforward method was demonstrated for efficient encapsulation of magnetic NPs into the engineered virus-like particles (VLPs) through the affinity of histidine tags for the methotrexate (MTX)-Ni2+ chelate. HBc144-His VLPs shell could protect Fe3O4-MTX NPs from the recognition by the reticuloendothelial system as well as could increase their cellular uptake efficiency. Through our well-designed tactic, the photothermal efficiency of Fe3O4 NPs were obviously improved in vitro and in vivo upon near-infrared (NIR) laser irradiation. Moreover, Magnetic resonance imaging (MRI) results showed that the Fe3O4-MTX@HBc core-shell NPs were reliable T2-type MRI contrast agents for tumor imaging. Hence the Fe3O4-MTX@HBc core-shell NPs may act as a promising theranostic platform for multimodal cancer treatment.

Chemotherapeutic drug-photothermal agent co-self-assembling nanoparticles for near-infrared fluorescence and photoacoustic dual-modal imaging-guided chemo-photothermal synergistic therapy.

Multimodal imaging-guided synergistic combination therapy has shown great potential for cancer treatment. However, the nanocarrier-based theranostic systems suffer from batch-to-batch variation, complexity of multicomponent, poor drug loading, and carrier-related toxicity issues. To address these issues, herein we developed a novel carrier-free theranostic system with nanoscale characteristics for near-infrared fluorescence (NIRF) and photoacoustic (PA) dual-modal imaging-guided synergistic chemo-photothermal therapy (PTT). Indocyanine green (ICG) and epirubicin (EPI) could co-self-assemble into small molecular nanoparticles (NPs) in aqueous solution without any molecular precursor or excipient via collaborative interactions (electrostatic, π-π stacking, and hydrophobic interactions). The exceptionally high dual-drug loading (∼92wt%) ICG-EPI NPs showed good physiological stability, preferable photothermal response, excellent NIRF/PA imaging properties, pH-/photo-responsive drug release behavior, and promoted cellular endocytosis compared with free ICG or EPI. Importantly, the ICG-EPI NPs showed excellent tumor targeting ability with high spatial resolution and deep penetration via in vivo NIRF/PA dual-modal imaging. Moreover, in comparison with individual chemotherapy or PTT, the combinational chemo-PTT therapy of ICG-EPI NPs with NIR laser irradiation synergistically induced apoptosis and death of cancer cells in vitro, and showed synergistic chemo-PTT efficiency in vivo as evidenced by highly efficient tumor ablation. Furthermore, the ICG-EPI NPs exhibited inappreciable toxicity. This co-self-assembly of both FDA-approved agents provides a safe and "Molecular economical" strategy in the rational design of multifunctional nano-theranostic systems for real-time self-monitoring intracellular drug delivery and targeting multimodal imaging-guided synergistic combination therapy.

Polydopamine-Coated Manganese Carbonate Nanoparticles for Amplified Magnetic Resonance Imaging-Guided Photothermal Therapy.

This study reports a multifunctional nanoparticle (NP) that can be used for amplified magnetic resonance image (MRI)-guided photothermal therapy (PTT) due to its surface coating with a polydopamine (PDA) shell. Importantly, by means of introducing the surface coating of PDA, large quantities of water can be trapped around the NPs allowing more efficient water exchange, leading to greatly improved MR contrast signals compared with those from NPs without the PDA coating. Further, a distinct photothermal effect can be obtained arising from the strong absorption of PDA in the near-infrared (NIR) region. By synthesizing multifunctional MnCO3@PDA NPs, for example, we found that the longitudinal relaxivity (r1) of MnCO3 NPs can improve from 5.7 to 8.3 mM-1 s-1. Subsequently, in vitro MRI and PTT results verified that MnCO3@PDA could serve as an excellent MRI/PTT theranostic agent. Furthermore, the MnCO3@PDA NPs were applied as an MRI/PTT theranostic agent for in vivo MRI-guided photothermal ablation of tumors by intratumoral injection in 4T1 tumor-bearing mice. The MR imaging result shows a significantly bright MR image in the tumor site. The MnCO3@PDA-mediated PTT result shows high therapeutic efficiency as a result of high photothermal conversion efficiency. The present strategy of amplified MRI-guided PTT based on PDA coating of NPs will be widely applicable to other multifunctional NPs.

Dually folate/CD44 receptor-targeted self-assembled hyaluronic acid nanoparticles for dual-drug delivery and combination cancer therapy.

Nanoparticles (NPs) functionalized with targeting ligands have shown promise, but are still limited by their nonspecific uptake by certain healthy tissues and cells that express low or even comparable levels of receptors. To increase their accumulation at tumor sites while decreasing the unintended toxicity, a possible solution is the involvement of two separate tumor-specific ligands in the localization. In this study, a dual tumor-targeting drug-loaded NP system was self-assembled by the amphiphilic conjugate of methotrexate-hyaluronic acid-octadecylamine (MTX-HA-OCA) with curcumin (CUR) encapsulated within the hydrophobic core (designated as MTX-HA-OCA/CUR NPs). The advantages of this nanosystem are that the anticancer drug MTX can be utilized as a tumor-targeting ligand toward folate receptors due to its structural similarity to folic acid (FA), and HA can serve as another tumor-targeting ligand toward CD44 receptors. The MTX-HA-OCA/CUR NPs are ∼70 nm in diameter and have sustained/controlled drug release behavior. An in vitro cellular uptake and competition inhibition study exhibited that MTX-HA-OCA/CUR NPs could significantly enhance the internalization efficiency in HeLa cells via folate/CD44 receptor-mediated endocytosis as compared to HA-OCA/CUR NPs. More importantly, the in vitro cytotoxicity of MTX-HA-OCA/CUR NPs was significantly enhanced as compared to those of the HA-OCA/CUR NPs, both free drugs, and individual free drug. Furthermore, the real-time in vivo and ex vivo fluorescence imaging of HeLa tumor-bearing mice showed that MTX-HA-OCA/CUR NPs could more efficiently enhance their accumulation and improve the penetration at the tumor site as compared to HA-OCA/CUR NPs. Therefore, these dually folate/CD44 receptor-targeted self-assembled HA NPs for the co-delivery of both anticancer drugs might provide a promising strategy for dual-targeted combination cancer therapy.

Protective effects of Phellinus linteus extract against iron overload-mediated oxidative stress in cultured rat hepatocytes.

Phellinus linteus (PL) mushroom has been reported to possess antioxidant activity. The present study was designed to investigate whether an ethanol extract obtained from PL might ameliorate oxidative stress and enhance antioxidant enzyme activities in primary rat hepatocytes, which were overloaded with iron using ferric nitrilotriacetate (FeNTA) complex. FeNTA enables hepatocytes to accumulate substantially redox-active iron and stimulates the production of injurious hydroxyl radicals, which in turn, initiate oxidative stress-mediated cytotoxicity. The results showed that pretreatment of hepatocytes with PL extract (50, 100 and 200 microg/mL) for 24 h significantly reversed FeNTA-induced cell viability loss, lactate dehydrogenase leakage (LDH), lipid peroxidation (LPO) and protein carbonyl formation in a dose-dependent manner. It was further observed that PL extract produced an inhibitory effect on intracellular reactive oxygen species (ROS) formation caused by FeNTA. Concomitantly, the amount of GSH content and the activities of glutathione reductase (GSH Rd) and glutathione peroxidase (GSH Px) in hepatocytes pretreated with PL extract increased substantially compared with those treated with FeNTA alone. These results suggest that PL may be useful in protecting against FeNTA-induced oxidative damage and also be capable of attenuating cytotoxicity of other oxidants.