Related Experiment Video
Updated: May 7, 2026
Photodynamic Therapy with Blended Conducting Polymer/Fullerene Nanoparticle Photosensitizers
Published on: October 28, 2015
Effects of Zinc Phthalocyanine Photodynamic Therapy on Vital Structures and Processes in Hela Cells
Jakub Hosik1, Barbora Hosikova1, Svatopluk Binder1
1Department of Medical Biophysics, Faculty of Medicine and Dentistry, Palacky University, 77900 Olomouc, Czech Republic.
Abstract:
This work presents results on the efficiency of newly designed zinc phthalocyanine-mediated photodynamic therapy of both tumoral and nontumoral cell models using the MTT assay. Further detailed examinations of mechanistic and cell biological effects were focused on the HELA cervical cancer cell model. Here, ROS production, changes in the mitochondrial membrane potential, the determination of genotoxicity, and protein changes determined by capillary chromatography and tandem mass spectrometry with ESI were analyzed. The results showed that, in vitro, 5 Jcm-2 ZnPc PDT caused a significant increase in reactive oxygen species. Still, except for superoxide dismutase, the levels of proteins involved in cell response to oxidative stress did not increase significantly. Furthermore, this therapy damaged mitochondrial membranes, which was proven by a more than 70% voltage-dependent channel protein 1 level decrease and by a 65% mitochondrial membrane potential change 24 h post-therapy. DNA impairment was assessed by an increased level of DNA fragmentation, which might be related to the decreased level of DDB1 (decrease in levels of more than 20% 24 h post-therapy), a protein responsible for maintaining genomic integrity and triggering the DNA repair pathways. Considering these results and the low effective concentration (LC50 = 30 nM), the therapy used is a potentially very promising antitumoral treatment.
Insights
Newly developed zinc phthalocyanine photodynamic therapy (ZnPc PDT) effectively targets cancer cells. This promising antitumoral treatment shows significant cell damage and low effective concentration, indicating potential for cancer therapy.
Area of Science:
- Biochemistry
- Cell Biology
- Photodynamic Therapy
Background:
- Photodynamic therapy (PDT) is an emerging cancer treatment modality.
- Zinc phthalocyanines (ZnPc) are photosensitizers used in PDT.
- Understanding the cellular mechanisms of ZnPc PDT is crucial for optimizing its efficacy.
Purpose of the Study:
- To evaluate the efficiency of a novel zinc phthalocyanine-mediated photodynamic therapy (ZnPc PDT).
- To investigate the mechanistic and cell biological effects of ZnPc PDT on tumoral and nontumoral cell models.
- To assess the potential of ZnPc PDT as an antitumoral treatment.
Main Methods:
- MTT assay for cell viability assessment.
- Analysis of reactive oxygen species (ROS) production.
- Measurement of mitochondrial membrane potential.
- Determination of genotoxicity and DNA fragmentation.
- Capillary chromatography and tandem mass spectrometry (ESI-MS/MS) for protein analysis.
Main Results:
- ZnPc PDT significantly increased ROS production in vitro.
- Significant damage to mitochondrial membranes was observed (70% decrease in VDAC1, 65% change in mitochondrial membrane potential).
- Increased DNA fragmentation and decreased DDB1 levels indicated genotoxicity.
- Low effective concentration (LC50 = 30 nM) was determined.
Conclusions:
- ZnPc PDT demonstrates significant efficacy in damaging cancer cells through ROS generation and mitochondrial dysfunction.
- The therapy induces genotoxicity, potentially through DDB1 downregulation.
- The low effective concentration and observed cellular damage highlight ZnPc PDT as a promising antitumoral strategy.
Related Concept Videos
01:17Studying the Cytoskeleton
01:19Protein Dynamics in Living Cells
Fluorescent recovery after photobleaching (FRAP) is a fluorescent-protein-based detection technique used to quantify protein movement rates within the cell. This method exposes a small portion of the cell to an intense laser beam. The laser beam causes permanent photobleaching of the fluorophore-tagged proteins in the exposed region. As the bleached...