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Proceedings Paper

What are the targets of photodynamic therapy?
Author(s): David Kessel; Michelle Castelli; John Reiners
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Paper Abstract

We previously classified photosensitizing agents based on sites of photodamage: mitochondria, lysosomes and the plasma membrane. More recent studies have indicated that the first target for the mitochondrial sensitizers is the anti-apoptotic protein bcl-2. Loss of bcl-2 results in a high bax/bcl-2 ratio, leading to an apoptotic response involving cytochrome c translocation. PDT with sensitizers that target lysosomes causes the release of lysosomal proteases that catalyze cleavage of the protein bid to a truncated form that can also initiate an apoptotic response. When the PDT target includes the plasma membrane, we found a greatly impaired apoptotic response, associated with caspase-3 photodamage. Sensitizers that localize in only lysosomes also catalyze variable levels of caspase photodamage, but apoptosis is only slightly impaired. PDT appears to be a highly-selective means for eradication of bcl-2, lysosomes or caspases, and can be a potentially useful tool in apoptosis research.

Paper Details

Date Published: 6 June 2002
PDF: 6 pages
Proc. SPIE 4612, Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy XI, (6 June 2002); doi: 10.1117/12.469340
Show Author Affiliations
David Kessel, Wayne State Univ. School of Medicine (United States)
Michelle Castelli, Wayne State Univ. (United States)
John Reiners, Wayne State Univ. (United States)


Published in SPIE Proceedings Vol. 4612:
Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy XI
Thomas J. Dougherty, Editor(s)

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