ABSTRACT
BACKGROUND: During myocardial ischemia/reperfusion (I/R), a large amount of reactive oxygen species (ROS) is produced. In particular, overproduction of hydrogen peroxide (H2O2) is considered to be a main cause of I/R-mediated tissue damage. We generated novel H2O2-responsive antioxidant polymer nanoparticles (PVAX and HPOX) that are able to target the site of ROS overproduction and attenuate the oxidative stress-associated diseases. In this study, nanoparticles were examined for their therapeutic effect on myocardial I/R injury. METHODS AND RESULTS: The therapeutic effect of nanoparticles during cardiac I/R was evaluated in mice. A single dose of PVAX (3 mg/kg) showed a significant improvement in both cardiac output and fraction shortening compared with poly(lactic-coglycolic acid) (PLGA) particle, a non-H2O2-activatable nanoparticle. PVAX also significantly reduced the myocardial infarction/area compared with PLGA (48.7±4.2 vs 14.5±2.1). In addition, PVAX effectively reduced caspase-3 activation and TUNEL-positive cells compared with PLGA. Furthermore, PVAX significantly decreased TNF-α and MCP-1 mRNA levels. To explore the antioxidant effect of PVAX by scavenging ROS, dihydroethidium staining was used as an indicator of ROS generation. PVAX effectively suppressed the generation of ROS caused by I/R, whereas a number of dihydroethidium-positive cells were observed in a group with PLGA I/R. In addition, PVAX significantly reduced the level of NADPH oxidase (NOX) 2 and 4 expression, which favors the reduction in ROS generation after I/R. CONCLUSIONS: Taken together, these results suggest that H2O2-responsive antioxidant PVAX has tremendous potential as a therapeutic agent for myocardial I/R injury.
Subject(s)
Antioxidants/pharmacology , Apoptosis/drug effects , Hydrogen Peroxide/metabolism , Myocardial Reperfusion Injury/metabolism , Nanoparticles , Oxidative Stress/drug effects , Reactive Oxygen Species/metabolism , Animals , Caspase 3/drug effects , Caspase 3/metabolism , Chemokine CCL2/drug effects , Chemokine CCL2/genetics , In Situ Nick-End Labeling , Male , Mice , NADPH Oxidase 2/drug effects , NADPH Oxidase 2/metabolism , NADPH Oxidase 4/drug effects , NADPH Oxidase 4/metabolism , Polymers , RNA, Messenger/drug effects , RNA, Messenger/metabolism , Tumor Necrosis Factor-alpha/drug effects , Tumor Necrosis Factor-alpha/geneticsABSTRACT
Overproduction of reactive oxygen species (ROS) such as hydrogen peroxide (H2O2) leads to oxidative stress, causing inflammation and cellular damages and death. H2O2 is one of the most stable and abundant ROS and H2O2-mediated oxidative stress is considered as a key mediator of cellular and tissue damages during ischemia/reperfusion (I/R) injury. Therefore, H2O2 could hold tremendous potential as a diagnostic biomarker and therapeutic target for oxidative stress-associated inflammatory conditions such as I/R injury. Here, we report a novel nanotheranostic agent that can express ultrasound imaging and simultaneous therapeutic effects for hepatic I/R treatment, which is based on H2O2-triggered CO2-generating antioxidant poly(vanillin oxalate) (PVO). PVO nanoparticles generate CO2 through H2O2-triggered oxidation of peroxalate esters and release vanillin, which exerts antioxidant and anti-inflammatory activities. PVO nanoparticles intravenously administrated remarkably enhanced the ultrasound signal in the site of hepatic I/R injury and also effectively suppressed the liver damages by inhibiting inflammation and apoptosis. To our best understanding, H2O2-responsive PVO is the first platform which generates bubbles to serve as ultrasound contrast agents and also exerts therapeutic activities. We therefore anticipate that H2O2-triggered bubble-generating antioxidant PVO nanoparticles have great potential for ultrasound imaging and therapy of H2O2-associated diseases.
Subject(s)
Antioxidants/chemistry , Hydrogen Peroxide/chemistry , Nanoparticles/chemistry , Polymers/chemistry , Reperfusion Injury/drug therapy , Theranostic Nanomedicine , Animals , Anti-Inflammatory Agents/chemistry , Anti-Inflammatory Agents/pharmacology , Antioxidants/pharmacology , Apoptosis/drug effects , Dioxanes/chemistry , Dioxanes/pharmacology , Hydrogen Peroxide/pharmacology , Inflammation/drug therapy , Male , Mice , Mice, Inbred BALB C , Oxidative Stress/drug effects , Polyesters/chemistry , Polyesters/pharmacology , Reactive Oxygen Species/metabolism , UltrasonographyABSTRACT
Overproduction of hydrogen peroxide (H2O2) causes oxidative stress and is the main culprit in the pathogenesis of ischemia/reperfusion (I/R) injury. Suppression of oxidative stress is therefore critical in the treatment of I/R injury. Here, we report H2O2-activatable antioxidant prodrug (BRAP) that is capable of specifically targeting the site of oxidative stress and exerting anti-inflammatory and anti-apoptotic activities. BRAP with a self-immolative boronic ester protecting group was designed to scavenge H2O2 and release HBA (p-hydroxybenzyl alcohol) with antioxidant and anti-inflammatory activities. BRAP exerted potent antioxidant and anti-inflammatory activity in lipopolysaccharide (LPS)- and H2O2-stimulated cells by suppressing the generation of ROS and pro-inflammatory cytokines. In mouse models of hepatic I/R and cardiac I/R, BRAP exerted potent antioxidant, anti-inflammatory and anti-apoptotic activities due to the synergistic effects of H2O2-scavenging boronic esters and therapeutic HBA. In addition, administration of high doses of BRAP daily for 7 days showed no renal or hepatic function abnormalities. Therefore BRAP has tremendous therapeutic potential as H2O2-activatable antioxidant prodrug for the treatment of I/R injuries.
Subject(s)
Antioxidants/pharmacology , Boronic Acids/pharmacology , Hydrogen Peroxide/antagonists & inhibitors , Prodrugs/pharmacology , Reperfusion Injury/prevention & control , Animals , Anti-Inflammatory Agents/pharmacology , Antioxidants/chemistry , Apoptosis/drug effects , Benzyl Alcohols/pharmacology , Boronic Acids/chemistry , Caspase 3/metabolism , Cell Line , Cells, Cultured , Gene Expression/drug effects , Hydrogen Peroxide/metabolism , Immunoblotting , Liver/blood supply , Liver/drug effects , Liver/metabolism , Male , Mice, Inbred BALB C , Microscopy, Confocal , Molecular Structure , Myocardial Reperfusion Injury/genetics , Myocardial Reperfusion Injury/metabolism , Myocardial Reperfusion Injury/prevention & control , Prodrugs/chemistry , Reactive Oxygen Species/antagonists & inhibitors , Reactive Oxygen Species/metabolism , Reperfusion Injury/genetics , Reperfusion Injury/metabolism , Reverse Transcriptase Polymerase Chain Reaction , Tumor Necrosis Factor-alpha/genetics , Tumor Necrosis Factor-alpha/metabolismABSTRACT
Cancer cells, compared with normal cells, are under oxidative stress associated with the increased generation of reactive oxygen species (ROS) including H2O2 and are also susceptible to further ROS insults. Cancer cells adapt to oxidative stress by upregulating antioxidant systems such as glutathione to counteract the damaging effects of ROS. Therefore, the elevation of oxidative stress preferentially in cancer cells by depleting glutathione or generating ROS is a logical therapeutic strategy for the development of anticancer drugs. Here we report a dual stimuli-responsive hybrid anticancer drug QCA, which can be activated by H2O2 and acidic pH to release glutathione-scavenging quinone methide and ROS-generating cinnamaldehyde, respectively, in cancer cells. Quinone methide and cinnamaldehyde act in a synergistic manner to amplify oxidative stress, leading to preferential killing of cancer cells in vitro and in vivo. We therefore anticipate that QCA has promising potential as an anticancer therapeutic agent.
Subject(s)
Antineoplastic Agents/pharmacology , Boron Compounds/pharmacology , Esters/pharmacology , Oxidative Stress/drug effects , Animals , Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/chemistry , Boron Compounds/chemical synthesis , Boron Compounds/chemistry , Cell Line , Chromatography, Liquid/methods , DNA Fragmentation , Esters/chemical synthesis , Esters/chemistry , Hydrogen Peroxide , Magnetic Resonance Spectroscopy , Male , Mice , Mice, Inbred BALB C , Mice, Nude , Neoplasms, Experimental/drug therapy , Random Allocation , Reactive Oxygen Species , Tandem Mass SpectrometryABSTRACT
Doxorubicin (DOX) is a commonly used anti-neoplastic agent but its clinical use is limited due to serious hepatic and cardiac side effects. DOX-induced toxicity is mainly associated with overproduction of reactive species oxygen (ROS) such as hydrogen peroxide (H2O2). We have recently developed H2O2-responsive anti-oxidant polymer, polyoxalate containing vanillyl alcohol (PVAX), which is designed to rapidly scavenge H2O2 and release vanillyl alcohol with anti-oxidant, anti-inflammatory and anti-apoptotic properties. In this study, we report that PVAX nanoparticles are novel therapeutic agents for treating DOX-induced cardiac and hepatic toxicity. Intraperitoneal injection of PVAX nanoparticles (4 mg/kg/day) resulted in significant inhibition in apoptosis in liver and heart of DOX-treated mice by suppressing the activation of poly (ADP ribose) polymerase 1 (PARP-1) and caspase-3. PVAX treatment also prevented DOX-induced cardiac dysfunction. Furthermore, survival rate (vehicle = 35% vs. PVAX = 75%; p < 0.05) was significantly improved in a PVAX nanoparticles-treated group compared with vehicle treated groups. Taken together, we anticipate that PVAX nanoparticles could be a highly specific and potent treatment modality in DOX-induced cardiac and hepatic toxicity.
Subject(s)
Antioxidants/therapeutic use , Cardiomyopathies/drug therapy , Hydrogen Peroxide/metabolism , Oxalic Acid/therapeutic use , Polymers/therapeutic use , Animals , Antioxidants/chemistry , Benzyl Alcohols/chemistry , Benzyl Alcohols/therapeutic use , Cardiomyopathies/chemically induced , Doxorubicin , Male , Mice , Mice, Inbred C57BL , Nanoparticles/chemistry , Nanoparticles/therapeutic use , Oxalic Acid/chemistry , Polymers/chemistryABSTRACT
pH-Responsive linkages have been widely exploited in the development of polymeric drug delivery systems, which trigger drug release selectively at tumor tissues or endosomes and lysosomes of cells. Herein we report new pH-sensitive amphiphilic poly(ketal adipate)-co-poly(ethylene glycol) block copolymers (PKA-PEG), which have acid-cleavable ketal linkages in their hydrophobic backbone. PKA-PEG copolymers self-assemble to form stable micelles with a mean diameter of ~175 nm, which can encapsulate a payload of anticancer drugs and rapidly dissociate to release drug payload at the acid environment. The micelles are biocompatible and exhibit abilities to disrupt endosomes to enhance the cytosol drug delivery. Taken together, we anticipate that the pH-sensitive PKA-PEG micelles have great potential as anticancer drug carriers.