title: Optimizing the design and in vitro evaluation of bioreactive glucose oxidase-microspheres for enhanced cytotoxicity against multidrug resistant breast cancer cells.
abstract: Glucose oxidase (GOX) encapsulated in alginate-chitosan microspheres (GOX-MS) was shown in our previous work to produce reactive oxygen species (ROS) in situ and exhibit anticancer effects in vitro and in vivo. The purpose of present work was to optimize the design and thus enhance the efficacy of GOX-MS against multidrug resistant (MDR) cancer cells. GOX-MS with different mean diameters of 4, 20 or 140 μm were prepared using an emulsification-internal gelation-adsorption-chitosan coating method with varying compositions and conditions. The GOX loading efficiency, loading level, relative bioactivity of GOX-MS, and GOX leakage were determined and optimal chitosan concentrations in the coating solution were identified. The influence of particle size on cellular uptake, ROS generation, cytotoxicity and their underlying mechanisms was investigated. At the same GOX dose and incubation time, smaller sized GOX-MS produced larger amounts of H2O2 in cell culture medium and greater cytotoxicity toward murine breast cancer MDR (EMT6/AR1.0) and wild type (EMT6/WT) cells. Fluorescence and confocal laser scanning microscopy revealed significant uptake of small sized (4 μm) GOX-MS by both MDR and WT cells, but no cellular uptake of large (140 μm) GOX-MS. The GOX-MS were equally effective in killing both MDR cells and WT cells. The cytotoxicity of the GOX formulations was positively correlated with membrane damage and lipid peroxidation. GOX-MS induced greater membrane damage and lipid peroxidation in MDR cells than the WT cells. These results suggest that the optimized, small micron-sized GOX-MS are highly effective against MDR breast cancer cells.
authors.affiliation: Advanced Pharmaceutics & Drug Delivery Laboratory, Leslie Dan Faculty of Pharmacy, University of Toronto, 144 College Street, Toronto, Ontario, Canada M5S 3M2.
authors.forename: Ji
authors.initials: J
authors.lastname: Cheng
authors.affiliation: Advanced Pharmaceutics & Drug Delivery Laboratory, Leslie Dan Faculty of Pharmacy, University of Toronto, 144 College Street, Toronto, Ontario, Canada M5S 3M2.
authors.forename: Qun
authors.initials: Q
authors.lastname: Liu
authors.affiliation: Advanced Pharmaceutics & Drug Delivery Laboratory, Leslie Dan Faculty of Pharmacy, University of Toronto, 144 College Street, Toronto, Ontario, Canada M5S 3M2.
authors.forename: Adam J
authors.initials: AJ
authors.lastname: Shuhendler
authors.affiliation: Departments of Medical Biophysics and Radiation Oncology, University of Toronto, 610 University Ave, Toronto, Ontario, Canada M5G 2M9.
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Rauth
authors.affiliation: Advanced Pharmaceutics & Drug Delivery Laboratory, Leslie Dan Faculty of Pharmacy, University of Toronto, 144 College Street, Toronto, Ontario, Canada M5S 3M2. Electronic address: xywu@phm.utoronto.ca.
authors.forename: Xiao Yu
authors.initials: XY
authors.lastname: Wu
mesh_terms: D000327:Adsorption; D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D048271:Chitosan / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D004339:Drug Compounding; D004353:Drug Evaluation, Preclinical; D018432:Drug Resistance, Multiple / Q000187:drug effects*; D019008:Drug Resistance, Neoplasm / Q000187:drug effects*; D004655:Emulsions / Q000737:chemistry; D005782:Gels / Q000737:chemistry; D005949:Glucose Oxidase / Q000737:chemistry / Q000494:pharmacology*; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects; D018613:Microscopy, Confocal; D008863:Microspheres; D010316:Particle Size; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D004655:Emulsions; D005782:Gels; D017382:Reactive Oxygen Species; D048271:Chitosan; D006861:Hydrogen Peroxide; D005949:Glucose Oxidase
keywords: Bioreactivity; Cell membrane damage; Cytotoxicity; Glucose oxidase encapsulated chitosan-alginate microspheres; Multidrug resistant cancer cells; Optimizing design