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Secondary ROS or peroxides after singlet oxygen production
Oral Abstracts boring cells, establishing a self-stimulating oxidative assault. These were followed by a wave of nuclear activation, translocation of c-Jun N-terminal kinase and apoptosis to 700 mm from the center of the photo-activation region. The propagation of these signaling processes could be inhibited by chemical or genetic blockade of gap junction (GJ) inter cellular communication (GJIC) but not by extracellular scavengers of ROS and RNS. Conclusion: GJICs translates local oxidative burst into propagating oxidative signals across cell barriers controlling the activity and death in remote bystander ECs. Applications to major vasculopathis and anti vascular therapeutics will be discussed. Acknowledgment: This study was supported by Susan Komen Foundation for the cure and the Israeli Science Foundation.
References [1] Vakrat-Haglili, et al. JACS 2005;127(17):6487—97. [2] Ashur I, et al. J Phys Chem 2009;113:8027—37. [3] Madar-Balakirski, et al. PLoS One 2010;5(4). doi:10.1016/j.pdpdt.2011.03.094 O087 Secondary ROS or peroxides after singlet oxygen production I. Lhommeau 1 , S. Douillard 1 , E. Bigot 2 , P. Guerin 3 , M. Krempf 4 , R. Bataille 5 , T. Patrice 1 1 Cancer Photobiology, CHU de Nantes — HGRL, 44093 Nantes, France 2 Biochemistry, CHU de Nantes — HGRL, 44093 Nantes, France 3 Cardiology, CHU de Nantes — HGRL, 44093 Nantes, France 4 Endocrinology, CHU de Nantes — HGRL, 44093 Nantes, France 5 Oncology, CHU de Nantes — HGRL, 44093 Nantes, France
Singlet oxygen (1 O2 ) is produced during photoreactions, by leucocytes and during energy production. It deactivates by producing secondary ROS and peroxides. We analysed the ROS production secondary to 1 O2 during a PDT reaction using rose Bengal (RB) (˚ 1 O : 0.75) and light exposure (514 nm) with human sera (HS) from 2 patients with various diseases or from various animals species. The non-specific DCFH/DCF system had been used to monitor the reaction intensity. Influence of species: Secondary ROS or peroxides production was 4 times higher in mice than HS. It was even higher in nude mice. When in aves no relationship had been found with the cladistic number of embranchments a linear relationship had been found for primates (r < 0.98). Influence of diseases: All diabetes mellitus but equilibrated type 2 induce an increase of secondary ROS or peroxides production. During a recent myocardial infarction coronary blood appears to produce twice the amount of ROS as compared to aortic blood. More ROS or peroxides are produced in sera of patients with progressing cancers whatever their origin. Finally following a bypass cardiac surgery ROS or peroxides are 2.5 more but the recovery of normal production is achieved in 24 h. These results demonstrate that PDT results based on 1 O2 may vary largely with the nature of the serum and the biochemical defences against oxidative species. Using PDT as a tool could provide information concerning the evaluation of sera oxidative impairments. doi:10.1016/j.pdpdt.2011.03.095
151 O088 Reactive oxygen species generation from photoexcited quantum dot nanoparticles: Type I versus Type II photochemical mechanism E. Yaghini 1 , K. Pirker 2 , C. Kay 2 , A.M. Seifalian 1 , A.J. MacRobert 1 1
Division of Surgery and Interventional Science, University College London, London, United Kingdom 2 Division of Structural and Molecular Biology, University College London, London, United Kingdom
Introduction: Quantum dots (QDs) are new class of fluorescent inorganic nanoparticles which have been widely used as diagnostic fluorescent probes for in vitro and preclinical in vivo studies. Their unique photophysical properties such as broad excitation and narrow emission spectrum, and resistance to photobleaching make them ideal for biological applications. In the biomedical arena, QDs are being studied both for their diagnostic and therapeutic applications, in particular the possibility of using QDs in photodynamic therapy. The potential of QDs for photoinduced formation of reactive oxygen species (ROS) through electron transfer (Type I) and energy transfer (Type II) was studied Methods and materials: The formation of ROS in aqueous solutions was studied by measurement of 1270 nm luminescence, oxygen consumption, electron paramagnetic resonance (EPR) spin trapping and fluorescence probes. Generation of ROS by QDs in cellular environments was investigated using laser scanning confocal microscopy and cell metabolic activity assays. Results: It was found that whereas singlet oxygen (1 O2 ) was not produced by photoexcited QDs, superoxide anion (O2 −• ) and hydroxyl radicals (OH• ) were generated by QDs, especially in the presence of a physiological concentration of electron donating agent including NADH. Using cell metabolic activity assays and various probes of ROS generation, the formation of ROS in cellular environments was demonstrated. Conclusion: Illumination of QD-treated cells and bacteria with light did affect viability. The above results, together with those of assays in the presence of various scavengers of specific ROS, indicate that the formation of ROS by QDs mainly proceeded via electron transfer. doi:10.1016/j.pdpdt.2011.03.096 O089 Preventive effect of ALA-PDT on UV radiation-induced skin carcinoma ¿C in vivo study in a mouse model X.L. Wang 1 , T. Lv 1 , H.W. Wang 1 , F. Miao 1 , J.J. Li 1 , Z. Huang 1,2 1 2
Shanghai Skin Diseases and STD Hospital, Shanghai, China University of Colorado Denver, CO, USA
Background and objective: Protection from sunlight exposure reduces the risk of photoaging and skin carcinomas. In addition to sun avoidance and sun protection, there is a need to develop new strategies to prevent cancerous and pre-cancerous lesion. This preliminary in vivo study explored the preventive effects of ALA-PDT in a mouse model. Materials and methods:. Female SKH-1 hairless mice were divided into UV group and UV + ALA-PDT group. UV irradiation at MED dose level was delivered four-day a week. ALA-PDT (2% ALA, 1.2 J/cm2 at 632 nm) was applied once a week. The changes of skinfold thickness, tumor number and tumor volume were recorded. UV-induced tumors were characterized by histopathological examination. The effects of ALA-PDT on the expression of cytokines (e.g. TNF-␣, IL-1 and IL-6) and apoptotic markers (e.g. cytochrome C, Caspase 3 and Caspase 9) were examined.
References [1] Vakrat-Haglili, et al. JACS 2005;127(17):6487—97. [2] Ashur I, et al. J Phys Chem 2009;113:8027—37. [3] Madar-Balakirski, et al. PLoS One 2010;5(4). doi:10.1016/j.pdpdt.2011.03.094 O087 Secondary ROS or peroxides after singlet oxygen production I. Lhommeau 1 , S. Douillard 1 , E. Bigot 2 , P. Guerin 3 , M. Krempf 4 , R. Bataille 5 , T. Patrice 1 1 Cancer Photobiology, CHU de Nantes — HGRL, 44093 Nantes, France 2 Biochemistry, CHU de Nantes — HGRL, 44093 Nantes, France 3 Cardiology, CHU de Nantes — HGRL, 44093 Nantes, France 4 Endocrinology, CHU de Nantes — HGRL, 44093 Nantes, France 5 Oncology, CHU de Nantes — HGRL, 44093 Nantes, France
Singlet oxygen (1 O2 ) is produced during photoreactions, by leucocytes and during energy production. It deactivates by producing secondary ROS and peroxides. We analysed the ROS production secondary to 1 O2 during a PDT reaction using rose Bengal (RB) (˚ 1 O : 0.75) and light exposure (514 nm) with human sera (HS) from 2 patients with various diseases or from various animals species. The non-specific DCFH/DCF system had been used to monitor the reaction intensity. Influence of species: Secondary ROS or peroxides production was 4 times higher in mice than HS. It was even higher in nude mice. When in aves no relationship had been found with the cladistic number of embranchments a linear relationship had been found for primates (r < 0.98). Influence of diseases: All diabetes mellitus but equilibrated type 2 induce an increase of secondary ROS or peroxides production. During a recent myocardial infarction coronary blood appears to produce twice the amount of ROS as compared to aortic blood. More ROS or peroxides are produced in sera of patients with progressing cancers whatever their origin. Finally following a bypass cardiac surgery ROS or peroxides are 2.5 more but the recovery of normal production is achieved in 24 h. These results demonstrate that PDT results based on 1 O2 may vary largely with the nature of the serum and the biochemical defences against oxidative species. Using PDT as a tool could provide information concerning the evaluation of sera oxidative impairments. doi:10.1016/j.pdpdt.2011.03.095
151 O088 Reactive oxygen species generation from photoexcited quantum dot nanoparticles: Type I versus Type II photochemical mechanism E. Yaghini 1 , K. Pirker 2 , C. Kay 2 , A.M. Seifalian 1 , A.J. MacRobert 1 1
Division of Surgery and Interventional Science, University College London, London, United Kingdom 2 Division of Structural and Molecular Biology, University College London, London, United Kingdom
Introduction: Quantum dots (QDs) are new class of fluorescent inorganic nanoparticles which have been widely used as diagnostic fluorescent probes for in vitro and preclinical in vivo studies. Their unique photophysical properties such as broad excitation and narrow emission spectrum, and resistance to photobleaching make them ideal for biological applications. In the biomedical arena, QDs are being studied both for their diagnostic and therapeutic applications, in particular the possibility of using QDs in photodynamic therapy. The potential of QDs for photoinduced formation of reactive oxygen species (ROS) through electron transfer (Type I) and energy transfer (Type II) was studied Methods and materials: The formation of ROS in aqueous solutions was studied by measurement of 1270 nm luminescence, oxygen consumption, electron paramagnetic resonance (EPR) spin trapping and fluorescence probes. Generation of ROS by QDs in cellular environments was investigated using laser scanning confocal microscopy and cell metabolic activity assays. Results: It was found that whereas singlet oxygen (1 O2 ) was not produced by photoexcited QDs, superoxide anion (O2 −• ) and hydroxyl radicals (OH• ) were generated by QDs, especially in the presence of a physiological concentration of electron donating agent including NADH. Using cell metabolic activity assays and various probes of ROS generation, the formation of ROS in cellular environments was demonstrated. Conclusion: Illumination of QD-treated cells and bacteria with light did affect viability. The above results, together with those of assays in the presence of various scavengers of specific ROS, indicate that the formation of ROS by QDs mainly proceeded via electron transfer. doi:10.1016/j.pdpdt.2011.03.096 O089 Preventive effect of ALA-PDT on UV radiation-induced skin carcinoma ¿C in vivo study in a mouse model X.L. Wang 1 , T. Lv 1 , H.W. Wang 1 , F. Miao 1 , J.J. Li 1 , Z. Huang 1,2 1 2
Shanghai Skin Diseases and STD Hospital, Shanghai, China University of Colorado Denver, CO, USA
Background and objective: Protection from sunlight exposure reduces the risk of photoaging and skin carcinomas. In addition to sun avoidance and sun protection, there is a need to develop new strategies to prevent cancerous and pre-cancerous lesion. This preliminary in vivo study explored the preventive effects of ALA-PDT in a mouse model. Materials and methods:. Female SKH-1 hairless mice were divided into UV group and UV + ALA-PDT group. UV irradiation at MED dose level was delivered four-day a week. ALA-PDT (2% ALA, 1.2 J/cm2 at 632 nm) was applied once a week. The changes of skinfold thickness, tumor number and tumor volume were recorded. UV-induced tumors were characterized by histopathological examination. The effects of ALA-PDT on the expression of cytokines (e.g. TNF-␣, IL-1 and IL-6) and apoptotic markers (e.g. cytochrome C, Caspase 3 and Caspase 9) were examined.