FRET analysis demonstrates a rapid activating of caspase-3 during PDT-induced apoptosis

Yunxia Wu; Qun Chen

doi:10.1117/12.710939

27 October 2006 FRET analysis demonstrates a rapid activating of caspase-3 during PDT-induced apoptosis

Yunxia Wu, Qun Chen

Proceedings Volume 6047, Fourth International Conference on Photonics and Imaging in Biology and Medicine; 60473H (2006) https://doi.org/10.1117/12.710939
Event: Fourth International Conference on Photonics and Imaging in Biology and Medicine, 2005, Tianjin, China

Abstract

Apoptosis is a very important cellular event that plays a key role in pathogeny and therapy of many diseases. In this study, a recombinant caspase-3 substrate was used as a fluorescence resonance energy transfer (FRET) probe to detect the activation of caspase-3, and to monitor apoptosis in human lung adenocarcinoma (ASTC-a- 1) cells. With laser scanning confocal microscopy, we found that Photofrin were localized primarily in mitochondria, the primary targets of Photofrin-PDT. By analyzing the dynamic changes of FRET fluorescence, the results indicate that the onset and completion of caspase-3 activation induced by PDT is more rapidly than that by tumor necrosis factor-α (TNF-α). The activation of caspase-3 by PDT started 20 minutes after treatment and completed in about 15 minutes. In comparison, the onset of caspase-3 activation by TNF-a was delayed by 3 hours and the completion of caspase-3 activation required a significantly longer time (approximately 90 minutes). These results indicated that the initiation and process of caspase-3 activation are different corresponding to different treatment methods. Our data suggest that caspase-3 activation mediated by the cell surface death receptors is slower than that of the mitochondrial pathway and the mitochondria is an efficient target to induce apoptosis.

Citation Download Citation

Yunxia Wu and Qun Chen "FRET analysis demonstrates a rapid activating of caspase-3 during PDT-induced apoptosis", Proc. SPIE 6047, Fourth International Conference on Photonics and Imaging in Biology and Medicine, 60473H (27 October 2006); https://doi.org/10.1117/12.710939

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