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Direct and Abscopal Antitumor Responses Elicited by AlPcNE-Mediated Photodynamic Therapy in a Murine Melanoma Model
José Athayde Vasconcelos Morais1,2, Pedro H A Barros3, Marcelo de Macedo Brigido3
1Laboratory of Nanoscience and Immunology, Faculty of Ceilandia, University of Brasilia Ceilandia Sul, Brasilia 72220-275, DF, Brazil.
Abstract:
Melanoma, the most aggressive form of skin cancer, presents a major clinical challenge due to its tendency to metastasize and recalcitrance to traditional therapies. Despite advances in surgery, chemotherapy, and radiotherapy, the outlook for advanced melanoma remains bleak, reinforcing the urgent need for more effective treatments. Photodynamic therapy (PDT) has emerged as a promising alternative, leading to targeted tumor destruction with minimal harm to surrounding tissues. In this study, the direct and abscopal antitumor effects of PDT in a bilateral murine melanoma model were evaluated. Although only one of the two tumors was treated, effects were observed in both. Our findings revealed significant changes in systemic inflammation and alterations in CD4+ and CD8+ T cell populations in treated groups, as evidenced by blood analyses and flow cytometry. High-throughput RNA sequencing (RNA-Seq) further unveiled shifts in gene expression profiles in both treated and untreated tumors. This research sheds light on the novel antitumor and abscopal effects of nanoemulsion of aluminum chloride phthalocyanine (AlPcNE)-mediated PDT in melanoma, highlighting the potential of different PDT protocols to modulate immune responses and to achieve more effective and targeted cancer treatments.
Insights
Photodynamic therapy (PDT) using aluminum chloride phthalocyanine nanoemulsion demonstrated significant antitumor effects in melanoma, including an abscopal effect on untreated tumors. PDT modulated systemic inflammation and T cell populations, suggesting potential for enhanced cancer treatment.
Area of Science:
- Oncology
- Immunology
- Photochemistry
Background:
- Melanoma is an aggressive skin cancer with poor prognosis in advanced stages.
- Traditional therapies like chemotherapy and radiotherapy have limited efficacy for metastatic melanoma.
- Photodynamic therapy (PDT) offers a targeted approach with minimal damage to healthy tissues.
Purpose of the Study:
- To evaluate the direct and abscopal (systemic) antitumor effects of aluminum chloride phthalocyanine nanoemulsion-mediated photodynamic therapy (AlPcNE-PDT) in a bilateral melanoma model.
- To investigate the impact of AlPcNE-PDT on systemic inflammation and immune cell populations.
- To explore gene expression changes in response to AlPcNE-PDT in both treated and untreated tumors.
Main Methods:
- Utilized a bilateral murine melanoma model where only one tumor was treated with AlPcNE-PDT.
- Conducted blood analyses and flow cytometry to assess systemic inflammation and T cell subsets (CD4+, CD8+).
- Performed high-throughput RNA sequencing (RNA-Seq) to analyze gene expression profiles in both treated and untreated tumors.
Main Results:
- AlPcNE-PDT induced significant antitumor effects in the directly treated tumors.
- Observable abscopal antitumor effects were noted in the untreated tumors within the same animal.
- Significant alterations in systemic inflammation markers and notable changes in CD4+ and CD8+ T cell populations were detected.
- RNA-Seq analysis revealed distinct gene expression profile shifts in both treated and untreated tumors, indicating a systemic response.
Conclusions:
- AlPcNE-PDT exhibits potent direct and abscopal antitumor activities in melanoma.
- PDT can effectively modulate systemic immune responses, including inflammation and T cell dynamics.
- This study highlights the potential of PDT-based strategies, particularly AlPcNE-PDT, for developing more effective and targeted melanoma treatments by leveraging immune modulation.
