Modifications of DAMPs levels in extracellular environment induced by aminolevulinic acid-based photodynamic therapy of esophageal cancer cells

Abstract

Purpose

Immunogenic cell death plays an important role in anticancer treatment because it combines cell death with appearance of damage associated molecular patterns that have the potential to activate anticancer immunity. Effects of damage associated molecular patterns induced by aminolevulinic acid-based photodynamic therapy were studied mainly on dendritic cells. They have not been deeply studied on macrophages that constitute the essential component of the tumor microenvironment. The aim of this study was to analyze features of esophageal cancer cell death in relation to release capacity of damage associated molecular pattern species, and to test the effect of related extracellular environmental alterations on macrophages.

Material and methods

Esophageal Kyse 450 carcinoma cells were subjected to aminolevulinic acid-based photodynamic therapy at different concentrations of aminolevulinic acid. Resting, IFN/LPS and IL-4 macrophage subtypes were prepared from monocytic THP-1 cell line. Cell death features and macrophage modifications were analyzed by fluorescence-based live cell imaging. ATP and HMGB1 levels in cell culture media were determined by ELISA assays. The presence of lipid peroxidation products in culture media was assessed by spectrophotometric detection of thiobarbituric acid reactive substances.

Results

Aminolevulinic acid-based photodynamic therapy induced various death pathways in Kyse 450 cells that included features of apoptosis, necrosis and ferroptosis. ATP amounts in extracellular environment of treated Kyse 450 cells increased with increasing aminolevulinic acid concentration. Levels of HMGB1, detectable by ELISA assay in culture media, were decreased after the treatment. Aminolevulinic acid-based photodynamic therapy induced lipid peroxidation of cellular structures and increased levels of extracellular lipid peroxidation products. Incubation of resting and IL-4 macrophages in conditioned medium from Kyse 450 cells treated by aminolevulinic acid-based photodynamic therapy induced morphological changes in macrophages, however, comparable alterations were induced also by conditioned medium from untreated cancer cells.

Conclusion

Aminolevulinic acid-based photodynamic therapy leads to alterations in local extracellular levels of damage associated molecular patterns, however, comprehensive studies are needed to find whether they can be responsible for macrophage phenotype modifications.

Keywords:

• Photodynamic therapy
• aminolevulinic acid
• ATP
• HMGB1
• macrophage
• DAMP
• lipid peroxidation

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This publication was created thanks to support within the Operational Program Integrated Infrastructure for the project: Research and development in medical sciences - the way to personalized treatment of serious neurological, cardiovascular and cancer diseases 313011T431, co-financed from the resources of the European Regional Development Fund. The research leading to presented results has received funding also from Laserlab-Europe V (European Union’s Horizon 2020 research and innovation programme under grant agreement no 871124).

Notes on contributors

Beata Čunderlíková

Beata Čunderlíková, RNDr., PhD, is an Associate Professor at the Institute of Medical Physics and Biophysics, Faculty of Medicine, Comenius University and researcher at the International Laser Centre-SCSTI in Bratislava, Slovakia, with background in biophysics.

Kristína Klučková

Kristína Klučková, MD, PhD, is a researcher at the Institute of Immunology, Faculty of Medicine, Comenius University in Bratislava, Slovakia, with interest in immuno-oncology.

Pavel Babál

Pavel Babál, PhD, MD, is a Professor of Pathology at the Institute of Pathological Anatomy, Faculty of Medicine, Comenius University in Bratislava, Slovakia.

Peter Mlkvý

Peter Mlkvý, PhD, MD, is the head of the Department of Laser Medicine at the St. Elisabeth Cancer Institute Hospital and researcher at the International Laser Centre-SCSTI in Bratislava, Slovakia.

Tibor Teplický

Tibor Teplický, PhD, is a researcher at the Institute of Medical Physics and Biophysics, Faculty of Medicine, Comenius University in Bratislava, Slovakia with background in biomedical physics.