- Email: [email protected]
Pheophytin a and b mediated photodynamic therapy against sensitive and multidrug-resistant breast cancer cells
130 O013 Endothelial cells are involved in the response to topical PpIX-PDT H.S. de Bruijn 1 , H.C. de Vijlder 2 , E.R.M. de Haas 2 , A. van der Ploeg-van den Heuvel 1 , F. van Zaane 1 , D. Schipper 3 , H.J.C.M. Sterenborg 1 , T.L.M. ten Hagen 3 , D.J. Robinson 1 1
ErasmusMC, CODT/Radiation Oncology, Rotterdam, The Netherlands 2 ErasmusMC, Dermatology, Rotterdam, The Netherlands 3 ErasmusMC, Surgical Oncology, Rotterdam, The Netherlands Introduction/Background: Photodynamic therapy (PDT) using protoporpyrin IX (PpIX) precursors like 5-aminolevulinic acid (ALA) or methyl-aminolevulinate (MAL) has shown to be effective in the treatment of various skin diseases. Pre-clinical studies have shown distinct differences between ALA and MAL in the response to PDT that may be contributed to differences in spatial distribution of PpIX. We therefore investigated this ex-vivo on normal mouse skin cryo-sections and in-vivo in the mouse skin-fold chamber model using intra-vital microscopy. Methods and results: Cryo-sections were stained with a fluorescent endothelial cell marker (CD31) and co-localization with PpIX fluorescence was determined using Pearson’s correlation analysis. ALA showed a significantly stronger correlation compared to MAL (p < 0.01). Intra-vital PpIX fluorescence distribution was imaged in the epidermis, upper dermis and lower dermis of skin and fluorescence intensity was determined with respect to hair follicles, arterioles, venules and (epi)dermal tissue. Vasoconstriction of vessels in response to light excitation was investigated and correlated with PpIX fluorescence intensity. High dose ALA-PDT resulted in strong arteriole and localized venule constriction (n = 4). No venule response and only weak arteriole responses were observed after MAL (n = 4). Low dose PDT showed similar results. The degree of vasoconstriction showed strong correlation with the fluorescence intensity measured in the vessel wall independent of the pre-cursor. Conclusion: Endothelial cells of normal mouse skin accumulate PpIX after topical application of ALA and, to a lesser degree, MAL. Our results show that besides direct cell kill also vascular responses play a role in the overall response to topical PpIX-PDT. doi:10.1016/j.pdpdt.2011.03.028 O014 Pheophytin a and b mediated photodynamic therapy against sensitive and multidrug-resistant breast cancer cells
Oral Abstracts Results: The viabilities of MCF-7 and MCF-7/ADR cells were found to diminish as the concentration of pheophytin, light dose, and incubation time increased. The IC50 value for MCF-7/ADR cells was twofold to that of MCF-7 cells. ROS formation of both cells was significantly increased post-PDT. Intracellular ATP level was decreased as the incubation time increased from 2 h to 6 h, where ATP depletion from pheophytin a-PDT was higher than that from pheophytin b-PDT. DNA fragmentation confirmed that cell death after PDT was mediated by apoptosis. Conclusion: This study demonstrated that pheophytin a and b possessed photocytotoxicity against sensitive and multidrugresistant breast cancer cells via apoptosis. The death mechanism mediated by pheophytin-PDT is under investigation. Acknowledgements: The study was supported in part by grants NSC 99-2221-E-033-027 and NSC 99-2627-E-033-001 from the National Science Council of Taiwan. doi:10.1016/j.pdpdt.2011.03.029 O015 Antivascular versus anticellular PDT. A proton and sodium MRI follow-up of human colorectal tumors implanted in mice M. Lupu 1,2 , F. Poyer 1,2 , P. Maillard 2,3 , A. Croisy 1,2 , C. Thomas 1,2 , G. Garcia 2,3 , J. Mispelter 1,2 1
Curie Institute/INSERM U759, Reserach, Orsay, France University Paris XI, Orsay, France 3 Curie Institute/CNRS UMR 176, Research, Orsay, France 2
Background: Photodynamic therapy is an established cancer treatment in which a non-mutagen photosensitizing agent is activated by exposure to visible light. Since an anti-tumoral treatment will damage tumor blood vessels and/or cells 23 Na MRI is an ideal endogenous probe to characterize the tissue cell density. Treatment protocols: Two regimens were devised for this study. Mice treated according to the anti-vascular regimen received one i.v. injection of PS (0.6 mg/kg polyethylene glycol 400/ethanol/physiological serum: 3/2/5 per volume) followed 10 min later by exposure to red light. The majority of PS being still in the vascular system, the overall effect of the PDT was anti-vascular. The second protocol targeted both cancer cells and blood vessels. One i.v. dose (0.6 mg/kg) of PS was followed by a second dose, separated by a 3 h interval. This time lapse allowed the first dose of PS to penetrate inside tumor cells. Shortly after the administration of the second dose (10 min), tumors were exposed to red light. As a consequence both cancer cells and blood vessels were targeted.
W.-T. Li 1,2 , J.-C. Chang 1 , N.-N. Hsieh 1 1
Chung-Yuan Christian University, Department Biomedical Engineering, Chung-Li, Taiwan 2 Chung-Yuan Christian University, R&D Center Biomedical Microdevice Technologies, Taiwan Introduction/Background: Photodynamic therapy (PDT) is a treatment modality that selectively kills tumor cells by reactive oxygen species (ROS) produced from the photosensitizer accumulated in tumor cells activated by irradiation with specific wavelength. Chlorophyll derivatives are ideal photosensitizers, which possess similar photophysical properties to those of the porphyrin systems with enhanced and red-shifted Q bands. The aim of this study was to study the photodynamic effects of pheophytin a and b on sensitive (MCF-7) and multidrug-resistant (MCF-7/ADR) breast cancer cells. Methods: Pheophytin a and b were used as photosensitizers. The effects of photosensitizer concentration, incubation time pre-PDT, light dose (660 nm) on cell viability, ROS formation, intracellular ATP level, and DNA fragmentation of MCF-7 and MCF-7/ADR cells after PDT were studied.
Results: The treatment protocols were applied on human colorectal tumors implanted on nude mice. Double targeting PDT prevents tumor progression in contrast to single targeting PDT (see figure).
ErasmusMC, CODT/Radiation Oncology, Rotterdam, The Netherlands 2 ErasmusMC, Dermatology, Rotterdam, The Netherlands 3 ErasmusMC, Surgical Oncology, Rotterdam, The Netherlands Introduction/Background: Photodynamic therapy (PDT) using protoporpyrin IX (PpIX) precursors like 5-aminolevulinic acid (ALA) or methyl-aminolevulinate (MAL) has shown to be effective in the treatment of various skin diseases. Pre-clinical studies have shown distinct differences between ALA and MAL in the response to PDT that may be contributed to differences in spatial distribution of PpIX. We therefore investigated this ex-vivo on normal mouse skin cryo-sections and in-vivo in the mouse skin-fold chamber model using intra-vital microscopy. Methods and results: Cryo-sections were stained with a fluorescent endothelial cell marker (CD31) and co-localization with PpIX fluorescence was determined using Pearson’s correlation analysis. ALA showed a significantly stronger correlation compared to MAL (p < 0.01). Intra-vital PpIX fluorescence distribution was imaged in the epidermis, upper dermis and lower dermis of skin and fluorescence intensity was determined with respect to hair follicles, arterioles, venules and (epi)dermal tissue. Vasoconstriction of vessels in response to light excitation was investigated and correlated with PpIX fluorescence intensity. High dose ALA-PDT resulted in strong arteriole and localized venule constriction (n = 4). No venule response and only weak arteriole responses were observed after MAL (n = 4). Low dose PDT showed similar results. The degree of vasoconstriction showed strong correlation with the fluorescence intensity measured in the vessel wall independent of the pre-cursor. Conclusion: Endothelial cells of normal mouse skin accumulate PpIX after topical application of ALA and, to a lesser degree, MAL. Our results show that besides direct cell kill also vascular responses play a role in the overall response to topical PpIX-PDT. doi:10.1016/j.pdpdt.2011.03.028 O014 Pheophytin a and b mediated photodynamic therapy against sensitive and multidrug-resistant breast cancer cells
Oral Abstracts Results: The viabilities of MCF-7 and MCF-7/ADR cells were found to diminish as the concentration of pheophytin, light dose, and incubation time increased. The IC50 value for MCF-7/ADR cells was twofold to that of MCF-7 cells. ROS formation of both cells was significantly increased post-PDT. Intracellular ATP level was decreased as the incubation time increased from 2 h to 6 h, where ATP depletion from pheophytin a-PDT was higher than that from pheophytin b-PDT. DNA fragmentation confirmed that cell death after PDT was mediated by apoptosis. Conclusion: This study demonstrated that pheophytin a and b possessed photocytotoxicity against sensitive and multidrugresistant breast cancer cells via apoptosis. The death mechanism mediated by pheophytin-PDT is under investigation. Acknowledgements: The study was supported in part by grants NSC 99-2221-E-033-027 and NSC 99-2627-E-033-001 from the National Science Council of Taiwan. doi:10.1016/j.pdpdt.2011.03.029 O015 Antivascular versus anticellular PDT. A proton and sodium MRI follow-up of human colorectal tumors implanted in mice M. Lupu 1,2 , F. Poyer 1,2 , P. Maillard 2,3 , A. Croisy 1,2 , C. Thomas 1,2 , G. Garcia 2,3 , J. Mispelter 1,2 1
Curie Institute/INSERM U759, Reserach, Orsay, France University Paris XI, Orsay, France 3 Curie Institute/CNRS UMR 176, Research, Orsay, France 2
Background: Photodynamic therapy is an established cancer treatment in which a non-mutagen photosensitizing agent is activated by exposure to visible light. Since an anti-tumoral treatment will damage tumor blood vessels and/or cells 23 Na MRI is an ideal endogenous probe to characterize the tissue cell density. Treatment protocols: Two regimens were devised for this study. Mice treated according to the anti-vascular regimen received one i.v. injection of PS (0.6 mg/kg polyethylene glycol 400/ethanol/physiological serum: 3/2/5 per volume) followed 10 min later by exposure to red light. The majority of PS being still in the vascular system, the overall effect of the PDT was anti-vascular. The second protocol targeted both cancer cells and blood vessels. One i.v. dose (0.6 mg/kg) of PS was followed by a second dose, separated by a 3 h interval. This time lapse allowed the first dose of PS to penetrate inside tumor cells. Shortly after the administration of the second dose (10 min), tumors were exposed to red light. As a consequence both cancer cells and blood vessels were targeted.
W.-T. Li 1,2 , J.-C. Chang 1 , N.-N. Hsieh 1 1
Chung-Yuan Christian University, Department Biomedical Engineering, Chung-Li, Taiwan 2 Chung-Yuan Christian University, R&D Center Biomedical Microdevice Technologies, Taiwan Introduction/Background: Photodynamic therapy (PDT) is a treatment modality that selectively kills tumor cells by reactive oxygen species (ROS) produced from the photosensitizer accumulated in tumor cells activated by irradiation with specific wavelength. Chlorophyll derivatives are ideal photosensitizers, which possess similar photophysical properties to those of the porphyrin systems with enhanced and red-shifted Q bands. The aim of this study was to study the photodynamic effects of pheophytin a and b on sensitive (MCF-7) and multidrug-resistant (MCF-7/ADR) breast cancer cells. Methods: Pheophytin a and b were used as photosensitizers. The effects of photosensitizer concentration, incubation time pre-PDT, light dose (660 nm) on cell viability, ROS formation, intracellular ATP level, and DNA fragmentation of MCF-7 and MCF-7/ADR cells after PDT were studied.
Results: The treatment protocols were applied on human colorectal tumors implanted on nude mice. Double targeting PDT prevents tumor progression in contrast to single targeting PDT (see figure).