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Proceedings Paper

PDT: death pathways
Author(s): David Kessel
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Paper Abstract

Cellular targets of photodynamic therapy include mitochondria, lysosomes, the endoplasmic reticulum (ER) and the plasma membrane. PDT can evoke necrosis, autophagy and apoptosis, or combinations of these, depending on the PDT dose, the site(s) of photodamage and the cellular phenotype. It has been established that loss of viability occurs even when the apoptotic program is inhibited. Studies assessing effects of ER or mitochondrial photodamage, involving loss of Bcl-2 function, indicate that low-dose PDT elicited a rapid autophagic response in L1210 cells. This was attributed to the ability of autophagy to recycle photodamaged organelles, and there was partial protection from loss of viability. This effect was not observed in L1210/Atg7, where autophagy was silenced. At higher PDT doses, apoptotic cells were observed within 60 min in both cell lines, but more so in L1210. The ability of L1210 cells to undergo autophagy did not offer protection from cell death at the higher PDT dose. Previous studies had indicated that autophagy can contribute to cell death, since L1210 cells that do not undergo an initial apoptotic response often contain multiple autophagic vacuoles 24 hr later. With L1210/Atg7, apoptosis alone may account for the loss of viability at an LD90 PDT dose.

Paper Details

Date Published: 9 February 2007
PDF: 7 pages
Proc. SPIE 6427, Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy XVI, 642702 (9 February 2007); doi: 10.1117/12.702441
Show Author Affiliations
David Kessel, Wayne State Univ. (United States)


Published in SPIE Proceedings Vol. 6427:
Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy XVI
David Kessel, Editor(s)

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