Generation Of Toxic Reactive Oxygen Species Research Articles

A biocompatible and pH-responsive nanohydrogel based on cellulose nanocrystal for enhanced toxic reactive oxygen species generation

Traditional therapeutic regimens are currently far from satisfactory, and the integration of biocompatible carbohydrate polymers and nanotechnologies with conventional therapeutics has become a focus of research in cancer therapy. Herein, A novel biocompatible and pH-responsive nanohydrogel composed of two functional polymeric chains was developed from cellulose nanocrystals (CNCs) and 5-aminolevulinic acid (ALA), or dopamine (DPA). The biological molecules PDA and ALA were respectively conjugated to CNC through the coordination of iron ions to form two functional polymeric chains (PDA/Fe@CNC and ALA/Fe@CNC). The PDA/Fe@CNC chain increased the adhesion of the nanohydrogels to cells, while the ALA/Fe@CNC chain significantly increased reactive oxygen species (ROS) production. Furthermore, PTX molecules loaded into the nanohydrogels combined with ROS to efficiently kill tumor cells. The nanohydrogels displayed excellent cell affinity, high ROS yield (8.0-fold greater than that in control), and strong cytotoxicity (2.7 % of cell viability). The present study highlights the great potential of biocompatible natural polysaccharide-based materials for biomedical applications, and provides a new strategy for reducing the toxicity and side effects associated with traditional chemotherapy, demonstrating a novel antitumor treatment paradigm with high-efficiency but with only minor side effects.

Iron Oxide Nanocarrier-Mediated Combination Therapy of Cisplatin and Artemisinin for Combating Drug Resistance through Highly Increased Toxic Reactive Oxygen Species Generation.

Combination therapy with multiple drugs through a multi-pronged assault as a strategy to combat cisplatin resistance shows great potential in biochemical therapy for cancer. However, inherent issues such as low drug loading and the poor synergistic effects of multiple drugs partially limit the further application of combination therapy. Here, we synthesized a new compound, ART-Chol, by coupling artemisinin and cholesterol as a base material combined with cyclic (Arg-Gly-Asp-d-Phe-Lys)]-poly(ethylene glycol) distearoylphosphatidylcholine (cRGD-PEG-DSPE) and phospholipids to form a magnetic liposome cRGD-AFePt@NPs encapsulating superparamagnetic ferric oxide nanoparticles and cisplatin for achieving high drug loading and a better synergistic effect. The cRGD-AFePt@NPs could be effectively internalized and responsively release loading cargos under alternating magnetic field irradiation due to local hyperthermia generated from magnetic nanoparticles by hysteresis loss and Néel relaxation. The generated Fe2+/Fe3+ from Fe3O4 NPs in the acid lysosomes motivated cisplatin and catalyzed the Fe-dependent anticancer drug artemisinin (ART) to generate highly toxic ROS through the Fenton reaction, which greatly enhances the anticancer effect of cisplatin with minimized side effects. In vitro cytotoxicity tests demonstrated that the cRGD-AFePt@NPs exhibited a 15.17-fold lower IC50 value of free cisplatin (IC50 = 32.47 μM) against A549/R cells. Further flow-cytometry tests also showed obviously increased intracellular ROS generation and cell apoptosis rates. We highlight the potential for Fe2+/Fe3+-mediated combination therapy of cisplatin and ART for circumventing cisplatin drug resistance.

Pharmacokinetics and derivation of an anticancer dosing regimen for the novel anti-cancer agent isobutyl-deoxynyboquinone (IB-DNQ), a NQO1 bioactivatable molecule, in the domestic felid species.

Isobutyl-deoxynyboquinone (IB-DNQ) is a selective substrate for NAD(P)H:quinone oxidoreductase (NQO1), an enzyme overexpressed in many solid tumors. Following activation by NQO1, IB-DNQ participates in a catalytic futile reduction/reoxidation cycle with consequent toxic reactive oxygen species generation within the tumor microenvironment. To elucidate the potential of IB-DNQ to serve as a novel anticancer agent, in vitro studies coupled with in vivo pharmacokinetic and toxicologic investigations in the domestic felid species were conducted to investigate the tractability of IB-DNQ as a translationally applicable anticancer agent. First, using feline oral squamous cell carcinoma (OSCC) as a comparative cancer model, expressions of NQO1 were characterized in not only human, but also feline OSCC tissue microarrays. Second, IB-DNQ mediated cytotoxicity in three immortalized feline OSCC cell lines were studied under dose-dependent and sequential exposure conditions. Third, the feasibility of administering IB-DNQ at doses predicted to achieve cytotoxic plasma concentrations and biologically relevant durations of exposure were investigated through pharmacokinetic and tolerability studies in healthy research felines. Intravenous administration of IB-DNQ at 1.0-2.0mg/kg achieved peak plasma concentrations and durations of exposure reaching or exceeding predicted in vitro cytotoxic concentrations. Clinical adverse side effects including ptyalism and tachypnea exhibited during and post-IV infusion of IB-DNQ were transient and tolerable. Additionally, IB-DNQ administration did not produce acute or delayed-onset unacceptable hematologic, non-hematologic, or off-target oxidative toxicities. Collectively, the findings reported here within provide important safety and pharmacokinetic data to support the continued development of IB-DNQ as a novel anticancer strategy for NQO1 expressing cancers.

Effect of sulphasalazine and its metabolites on the generation of reactive oxygen species.

The relative in vitro anti-oxidant efficacy of sulphasalazine (salicylazosulphapyridine, SASP) and its metabolites (5-aminosalicylic acid, 5-ASA; sulphapyridine, SP) was examined by studying their effects on the generation of reactive oxygen species (ROS) using zymosan-stimulated polymorphonuclear leucocytes (PMNs) and a cell free, xanthine-xanthine oxidase system. Salicylazosulphapyridine, 5-ASA, and SP showed anti-oxidant effects to the various degrees. In particular, production of OH, which is one of the most potent reactive oxygen species, was remarkably suppressed by 5-ASA dose relatedly. These findings suggest that SASP and its metabolites play an important role in the inhibition of respiratory bursts. As the potent products of the respiratory burst by polymorphonuclear leucocytes are thought to be important inflammatory mediators, suppression of toxic reactive oxygen species generation by these agents may partly explain the therapeutic efficacy of SASP in ulcerative colitis, which is characterised by an acute mucosal inflammation dominated by polymorphonuclear leucocytes accumulation.