Smart Macrocycles: Cyclodextrin-Porphyrin Photosensitizers for Photodynamic Therapy in Human Bladder Cancer Cells

Area of Science:

• Biochemistry and Molecular Biology
• Oncology
• Photochemistry

Background:

• Urothelial carcinoma of the bladder presents therapeutic challenges due to high recurrence and treatment resistance.
• Photodynamic therapy (PDT) offers a minimally invasive approach for bladder cancer ablation via photosensitizers (PS) and light activation.
• Limitations of current porphyrin-based PS include poor solubility and aggregation, hindering clinical use.

Purpose of the Study:

• To evaluate the biological activity of novel thiopyridinium porphyrin-cyclodextrin conjugates (Por-CD 1a-3a).
• To assess the impact of these conjugates on solubility, cellular uptake, and photodynamic efficacy in bladder cancer cells.
• To identify promising candidates for optimizing PDT strategies against bladder cancer.

Main Methods:

• Synthesis and biological evaluation of three thiopyridinium porphyrin-cyclodextrin conjugates (Por-CD 1a-3a).
• Assessment of cellular uptake kinetics in UM-UC-3 human bladder cancer cell line.
• Evaluation of dark toxicity and phototoxicity following light irradiation.

Main Results:

• Por-CD conjugates demonstrated enhanced solubility and distinct cellular uptake patterns.
• All compounds were safe in the absence of light, showing no significant dark toxicity.
• Following light activation, PS 1a-3a exhibited potent photodynamic effects, with varying cytotoxicity profiles linked to absorption properties.

Conclusions:

• Thiopyridinium porphyrin-cyclodextrin conjugates possess favorable cellular internalization and potent photodynamic efficacy.
• The conjugates show promise for improving PDT strategies in bladder cancer treatment.
• Specific conjugates demonstrate distinct uptake and phototoxicity kinetics, offering potential for tailored therapeutic approaches.