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Updated: Jun 19, 2026

An In-House-Built and Light-Emitting-Diode-Based Photodynamic Therapy Device for Enhancing Verteporfin Cytotoxicity in a 2D Cell Culture Model
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An In-House-Built and Light-Emitting-Diode-Based Photodynamic Therapy Device for Enhancing Verteporfin Cytotoxicity in a 2D Cell Culture Model

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Death pathways associated with photodynamic therapy.

David Kessel1

  • 1Departments of Pharmacology and Medicine, Wayne State University School of Medicine, Detroit MI 48201, USA.

Medical Laser Application : International Journal for Laser Treatment and Research
|November 6, 2009
PubMed
Summary
This summary is machine-generated.

Photodynamic therapy (PDT) can trigger cell death pathways. Depending on the cellular target, PDT induces apoptosis or autophagy, influencing tumor cell fate and immune responses.

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An In Vitro Approach to Photodynamic Therapy
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Published on: August 17, 2018

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Last Updated: Jun 19, 2026

An In-House-Built and Light-Emitting-Diode-Based Photodynamic Therapy Device for Enhancing Verteporfin Cytotoxicity in a 2D Cell Culture Model
11:04

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Published on: January 13, 2023

An In Vitro Approach to Photodynamic Therapy
04:53

An In Vitro Approach to Photodynamic Therapy

Published on: August 17, 2018

Area of Science:

  • Cell Biology
  • Biochemistry
  • Oncology

Background:

  • Photodynamic therapy (PDT) is a treatment modality that utilizes photosensitizers and light to generate reactive oxygen species, leading to cell death.
  • The specific cellular targets of PDT and their downstream effects on cell fate pathways, such as apoptosis and autophagy, are complex and not fully elucidated.

Purpose of the Study:

  • To investigate the differential outcomes of photodynamic therapy (PDT) based on the subcellular localization of photosensitizer-induced photodamage.
  • To elucidate the roles of apoptosis and autophagy in response to PDT-induced cellular damage.

Main Methods:

  • Targeting of mitochondria, endoplasmic reticulum, lysosomes, or plasma membrane with photosensitizers followed by light activation.
  • Analysis of protein photodamage, including anti-apoptotic protein Bcl-2 and pro-apoptotic protein Bid.
  • Assessment of apoptotic and autophagic pathway activation.
  • Evaluation of apoptosis impairment and immune responses.

Main Results:

  • Photodamage to mitochondria or endoplasmic reticulum led to Bcl-2 photodamage and subsequent apoptosis when the pathway was available.
  • Lysosomal photodamage activated Bid, promoting apoptosis.
  • Plasma membrane photodamage resulted in sensitizer migration and procaspase photodamage, impairing apoptosis.
  • In the absence of functional apoptosis, cells underwent autophagy.
  • Autophagy was observed concurrently with apoptosis in some PDT responses and may contribute to immune responses against photodamaged tumor cells.

Conclusions:

  • The subcellular site of photodamage dictates the cell death pathway activated by PDT, predominantly apoptosis or autophagy.
  • PDT-induced apoptosis can be modulated by the integrity of the apoptotic machinery and the specific photodamaged targets.
  • Autophagy serves as an alternative cell death pathway when apoptosis is compromised and may play a role in anti-tumor immunity.