Sequential Protein-Responsive Nanophotosensitizer Complex for Enhancing Tumor-Specific Therapy

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Cancer Therapy

Background:

• Developing tumor-specific cancer therapies with minimal side effects remains a significant challenge.
• Photodynamic therapy (PDT) using activatable photosensitizers (aPSs) offers a promising approach for cancer treatment.
• Existing methods often lack specificity and can lead to off-target toxicity.

Purpose of the Study:

• To develop a sequential protein-responsive activatable photosensitizer (aPS) for enhanced cancer-specific photodynamic therapy.
• To investigate the selective activation and phototoxicity of the developed aPS in cancer cells.
• To evaluate the in vivo efficacy and safety profile of the aPS in a preclinical cancer model.

Main Methods:

• Fabrication of a sequential protein-responsive aPS (PcC4-MSN-O1) using zinc(II) phthalocyanine derivative (PcC4)-entrapped mesoporous silica nanoparticles (MSNs) with a DNA biogate (O1).
• Assessment of PcC4-MSN-O1 photoactivity modulation upon sequential reaction with telomerase and albumin.
• Evaluation of selective phototoxicity against cancer cells (HeLa) versus normal cells (HEK-293) in vitro.
• In vivo studies in xenograft-bearing mice to assess PcC4-MSN-O1 tumor accumulation, therapeutic efficacy upon laser irradiation, and excretion profile.

Main Results:

• PcC4-MSN-O1 exhibits self-quenching photoactivity, which is dramatically activated upon sequential interaction with telomerase and albumin.
• The developed aPS demonstrates selective phototoxicity towards cancer cells (HeLa) compared to normal cells (HEK-293).
• Systemic administration resulted in significant accumulation in HeLa tumors, and laser irradiation effectively inhibited tumor growth in vivo.
• Time-modulated activation and relatively fast excretion suggest reduced potential for side effects.

Conclusions:

• The developed sequential protein-responsive aPS (PcC4-MSN-O1) offers a novel strategy for cancer-specific photodynamic therapy.
• This system achieves targeted activation and enhanced phototoxicity within the tumor microenvironment.
• PcC4-MSN-O1 demonstrates promising preclinical efficacy and a favorable safety profile for cancer treatment.