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Huang C.-C.,National Tsing Hua University | Chia W.-T.,National Taiwan University Hospital | Chung M.-F.,National Tsing Hua University | Lin K.-J.,Center for Advanced Molecular Imaging and Translation | And 6 more authors.
Journal of the American Chemical Society | Year: 2016

In the absence of adequate oxygen, cancer cells that are grown in hypoxic solid tumors resist treatment using antitumor drugs (such as doxorubicin, DOX), owing to their attenuated intracellular production of reactive oxygen species (ROS). Hyperbaric oxygen (HBO) therapy favorably improves oxygen transport to the hypoxic tumor tissues, thereby increasing the sensitivity of tumor cells to DOX. However, the use of HBO with DOX potentiates the ROS-mediated cytotoxicity of the drug toward normal tissues. In this work, we hypothesize that regional oxygen treatment by an implanted oxygen-generating depot may enhance the cytotoxicity of DOX against malignant tissues in a highly site-specific manner, without raising systemic oxygen levels. Upon implantation close to the tumor, the oxygen-generating depot reacts with the interstitial medium to produce oxygen in situ, effectively shrinking the hypoxic regions in the tumor tissues. Increasing the local availability of oxygen causes the cytotoxicity of DOX that is accumulated in the tumors to be significantly enhanced by the elevated production of ROS, ultimately allaying the hypoxia-induced DOX resistance in solid malignancies. Importantly, this enhancement of cytotoxicity is limited to the site of the tumors, and this feature of the system that is proposed herein is unique. © 2016 American Chemical Society.

Rau L.-R.,Chang Gung University | Huang W.-Y.,Chang Gung University | Liaw J.-W.,Chang Gung University | Liaw J.-W.,Center for Advanced Molecular Imaging and Translation | And 2 more authors.
International Journal of Nanomedicine | Year: 2016

The specific properties of gold nanoparticles (AuNPs) make them a novel class of photothermal agents that can induce cancer cell damage and even death through the conversion of optical energy to thermal energy. Most relevant studies have focused on increasing the precision of cell targeting, improving the efficacy of energy transfer, and exploring additional functions. Nevertheless, most cells can uptake nanosized particles through nonspecific endocytosis; therefore, before hyperthermia via AuNPs can be applied for clinical use, it is important to understand the adverse optical–thermal effects of AuNPs on nontargeted cells. However, few studies have investigated the thermal effects induced by pulsed laser-activated AuNPs on nearby healthy cells due to nonspecific treatment. The aim of this study is to evaluate the photothermal effects induced by AuNPs plus a pulsed laser on MG63, an osteoblast-like cell line, specifically examining the effects on cell morphology, viability, death program, and differentiation. The cells were treated with media containing 50 nm AuNPs at a concentration of 5 ppm for 1 hour. Cultured cells were then exposed to irradiation at 60 mW/cm2 and 80 mW/cm2 by a Nd:YAG laser (532 nm wavelength). We observed that the cytoskeletons of MG63 cells treated with bare AuNPs followed by pulsed laser irradiation were damaged, and these cells had few bubbles on the cell membrane compared with those that were not treated (control) or were treated with AuNPs or the laser alone. There were no significant differences between the AuNPs plus laser treatment group and the other groups in terms of cell viability, death program analysis results, or alkaline phosphatase and calcium accumulation during culture for up to 21 days. However, the calcium deposit areas in the cells treated with AuNPs plus laser were larger than those in other groups during the early culture period. © 2016 Rau et al.

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