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Selective photo-ablation of glioma cells using an enzyme activatable photosensitizer
Zhenhua Shen1, Ching-Hsuan Tung
1Molecular Imaging Innovations Institute, Department of Radiology, Weill Cornell Medicine, New York, NY 10021, USA. cht2018@med.cornell.edu.
Abstract:
An activatable photosensitizer based on methylene blue was developed and validated for its efficacy in the selective killing of γ-glutamyl transpeptidase expressing cells. The 1O2 deactivation via bond breakage, rapid in situ enzymatic photosensitivity conversion, long lysosomal retention, and nucleus relocation collectively contribute to its strong and selective photodynamic effects.
Insights
A novel photosensitizer selectively targets and eliminates cancer cells expressing gamma-glutamyl transpeptidase. This methylene blue derivative offers enhanced photodynamic therapy by activating within cells for precise cancer treatment.
Area of Science:
- Photodynamic therapy
- Bioconjugate chemistry
- Cancer cell targeting
Background:
- Selective cancer cell killing remains a challenge in photodynamic therapy (PDT).
- Developing activatable photosensitizers can improve therapeutic specificity and reduce side effects.
- Enzyme-responsive systems offer a promising strategy for targeted drug delivery and activation.
Purpose of the Study:
- To develop and validate an activatable photosensitizer for selective photodynamic killing of cancer cells.
- To investigate the mechanism underlying the selective phototoxicity of the developed photosensitizer.
- To evaluate the potential of this approach for targeted cancer therapy.
Main Methods:
- Synthesis of a methylene blue-based activatable photosensitizer.
- In vitro validation using cell lines with varying levels of gamma-glutamyl transpeptidase expression.
- Assessment of photosensitizer uptake, intracellular localization, and photodynamic activity.
- Analysis of reactive oxygen species generation and cell death pathways.
Main Results:
- The developed photosensitizer demonstrated potent and selective phototoxicity against gamma-glutamyl transpeptidase expressing cells.
- Enzymatic activation within cells led to rapid conversion and enhanced photosensitivity.
- The photosensitizer exhibited prolonged lysosomal retention and nucleus relocation, contributing to efficacy.
- Effective singlet oxygen (1O2) generation and deactivation via bond breakage were observed.
Conclusions:
- An activatable methylene blue-based photosensitizer effectively targets and eliminates gamma-glutamyl transpeptidase expressing cells.
- The photosensitizer's design facilitates in situ activation and localization, leading to strong, selective photodynamic effects.
- This approach holds promise for developing targeted photodynamic therapies with improved specificity.
