Photodynamic therapy: combined modality approaches targeting the tumor microenvironment
Charles J Gomer1, Angela Ferrario, Marian Luna
1The Saban Research Institute, Children's Hospital Los Angeles, University of Southern California, Los Angeles, California 90027, USA. cgomer@chla.usc.edu
Lasers in Surgery and Medicine
|April 12, 2006
Summary
Photodynamic therapy (PDT) impacts the tumor microenvironment, affecting angiogenesis and inflammation. Combining PDT with targeted inhibitors can improve treatment effectiveness against cancer.
Area of Science:
- Oncology
- Photochemistry
- Immunology
Background:
- Photodynamic therapy (PDT) exerts direct cytotoxicity on malignant tumor cells.
- PDT also influences non-malignant tumor microenvironment components, potentially mediating angiogenesis and inflammation.
- These PDT-induced changes are critical determinants of treatment responsiveness.
Purpose of the Study:
- To investigate the modulation of the tumor microenvironment by PDT in preclinical models.
- To assess the role of angiogenic and inflammatory factors in PDT efficacy.
Main Methods:
- Preclinical studies utilizing mouse tumor models were conducted.
- Expression and function of angiogenic growth factors, proteinases, and inflammatory molecules were monitored post-PDT.
- Specific focus on Photofrin-mediated PDT.
Main Results:
- Photofrin-mediated PDT significantly activates vascular endothelial growth factor (VEGF), matrix metalloproteinases (MMPs), and COX-2 derived prostaglandins.
- These activated molecules are key components of the tumor microenvironment.
- Inhibitors targeting these factors enhance PDT effectiveness.
Conclusions:
- Combined modality treatments targeting both malignant cells and PDT-induced angiogenesis/inflammation can improve tumor responsiveness.
- Modulating the tumor microenvironment is a promising strategy to enhance PDT efficacy.
- Further research into combined regimens is warranted.
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