Photoactivated Rose Bengal Triggers Phospholipid Hydroperoxidation and Late Apoptosis in Colorectal Cancer Cells

Author(s)

Ferreira, Andre Satoshi ; de Almeida Junior, Alexandre Mendes ; Kobal, Mirella Boaro ; Moreira, Lucas Gontijo ; Camacho, Sabrina Alessio ; de Toledo, Karina Alves ; Oliveira Jr, Osvaldo N. ; Dewolf, Christine E. ; Aoki, Pedro Henrique Benites

• Document type: Journal article
• Source: Langmuir; v. 41, n. 10, p. 12-pg., 2025-03-06.

Abstract

Rose Bengal (RB) is a promising photosensitizer (PS) for photodynamic therapy (PDT), but its application to colorectal carcinoma remains largely unexplored. Herein, we employ in vitro assays to demonstrate that incorporation of RB has substantial phototoxicity against Caco-2 cells, with more than 80% reduction in cell viability for 24 h incubation with 5 x 10-6 mol/L RB followed by irradiation. In contrast, RB had minimal toxicity without irradiation. The mechanisms of RB action were further elucidated using confocal fluorescence microscopy, Langmuir monolayers as cell membrane models, and flow cytometry to determine the cell death pathways. Flow cytometry revealed that the primary mode of cell death was late apoptosis. RB incorporation affected Caco-2 plasma membrane morphology under light irradiation, and membrane interactions were confirmed using Langmuir monolayers of Caco-2 lipid extracts. Incorporation of RB into the monolayers shifted the pressure-area isotherms toward larger molecular areas, especially at low surface pressures and increasing RB concentrations (1, 10, and 25 x 10-6 mol/L). RB adsorption also caused a decrease in the in-plane elasticity (Cs1-) of the Caco-2 monolayers, with a large increase in monolayer flexibility as RB concentration increased. According to polarization-modulated infrared reflection absorption spectroscopy (PM-IRRAS), the anionic RB interacted electrostatically with positively charged phospholipid groups. Moreover, the changes in surface area observed in the monolayers upon RB incorporation and irradiation could be attributed to hydroperoxidation reactions triggered by the generation of singlet oxygen (1O2). These findings indicate that RB may be used as a PS in the PDT of colorectal cancer, providing detailed insights into its mechanism of action and phototoxicity. (AU)

• FAPESP's process: 23/01999-3 - Photoinduced modifications triggered by rose bengal in bioinspired and in vitro systems
• Grantee: André Satoshi Ferreira
• Support Opportunities: Scholarships abroad - Research Internship - Master's degree
• FAPESP's process: 21/14500-1 - Towards convergence of photodynamic (TFD) and photothermal (TFT) therapies on in vitro culture of melanoma-derived cells
• Grantee: Mirella Boaro Kobal
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 22/02189-2 - Plasmonic nanostructures for synergistic photodynamic (PDT) and photothermal (PTT) therapy of cancer cells
• Grantee: Pedro Henrique Benites Aoki
• Support Opportunities: Research Grants - Initial Project
• FAPESP's process: 14/11408-3 - Multi-User Equipment approved in grant 2013/14262-7: confocal microscope
• Grantee: Osvaldo Novais de Oliveira Junior
• Support Opportunities: Multi-user Equipment Program
• FAPESP's process: 23/17867-9 - Multifunctional approach of gold nanostructures coated with silica: combining the diagnosis of circulating cancer cells with the tumor phototherapy
• Grantee: Sabrina Aléssio Camacho
• Support Opportunities: Research Grants - Young Investigators Grants
• FAPESP's process: 24/15686-0 - Multifunctional approach of gold nanostructures coated with silica: combining the diagnosis of circulating cancer cells with the tumor phototherapy
• Grantee: Sabrina Aléssio Camacho
• Support Opportunities: Scholarships in Brazil - Young Researchers
• FAPESP's process: 21/14020-0 - Photosensitization of colorectal carcinoma model systems mediated by the xanthene rose bengal
• Grantee: André Satoshi Ferreira
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 20/15854-9 - Modulating photochemical reactions in Escherichia coli lipid monolayers with the binding mechanisms of eosin decyl ester and toluidine blue-O photosensitizers
• Grantee: Lucas Gontijo Moreira
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 23/07375-1 - Multi-user equipment approved in grant 2022/02189-2: flow cytometer
• Grantee: Pedro Henrique Benites Aoki
• Support Opportunities: Multi-user Equipment Program
• FAPESP's process: 24/11383-2 - Functionalized gold nanostars for specific photothermal therapy of colorectal cancer: studies in membrane models and cell cultures
• Grantee: André Satoshi Ferreira
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 18/22214-6 - Towards a convergence of technologies: from sensing and biosensing to information visualization and machine learning for data analysis in clinical diagnosis
• Grantee: Osvaldo Novais de Oliveira Junior
• Support Opportunities: Research Projects - Thematic Grants