Additional approach to PDT: type III mechanism and the role of native free radicals

Gál, D.; Kriska, Tamás; Shutova, T. G.; Németh, András

doi:10.1117/12.424450

Cited by 5 publications

(2 citation statements)

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“…Alternative MOAs to the type I and type II pathways have been reported in literature despite a lack of consensus regarding the definition of oxygen-independent mechanisms. , A modified type I mechanism, called type III, has been described based on an interaction between the PS in its first excited triplet state and doublet free radicals with diffusion-controlled rate constants. − Other reports of oxygen-independent mechanisms involve the generation of toxic photoproducts from upper excited triplet states, photoinduced electron transfers leading to cycloaddition reactions, , and structural changes upon excitation that allow binding to intracellular targets. , These properties currently preclude therapeutic deployment. Additional agents for phototherapy undergoing photoredox catalysis have been reported recently. , …”

Section: Introductionmentioning

confidence: 99%

BODIPY-Based Photothermal Agents with Excellent Phototoxic Indices for Cancer Treatment

et al. 2023

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Here, we report six novel, easily accessible BODIPY-based agents for cancer treatment. In contrast to established photodynamic therapy (PDT) agents, these BODIPY-based compounds show additional photothermal activity and their cytotoxicity is not dependent on the generation of reactive oxygen species (ROS). The agents show high photocytotoxicity upon irradiation with light and low dark toxicity in different cancer cell lines in 2D culture as well as in 3D multicellular tumor spheroids (MCTSs). The ratio of dark to light toxicity (phototoxic index, PI) of these agents reaches striking values exceeding 830,000 after irradiation with energetically low doses of light at 630 nm. The oxygen-dependent mechanism of action (MOA) of established photosensitizers (PSs) hampers effective clinical deployment of these agents. Under hypoxic conditions (0.2% O2), which are known to limit the efficiency of conventional PSs in solid tumors, photocytotoxicity was induced at the same concentration levels, indicating an oxygen-independent photothermal MOA. With a PI exceeding 360,000 under hypoxic conditions, both PI values are the highest reported to date. We anticipate that small molecule agents with a photothermal MOA, such as the BODIPY-based compounds reported in this work, may overcome this barrier and provide a new avenue to cancer therapy.

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Section: Introductionmentioning

confidence: 99%

BODIPY-Based Photothermal Agents with Excellent Phototoxic Indices for Cancer Treatment

et al. 2023

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“…10,13 A modified type I mechanism, called type III, has been described based on an interaction between the PS in its first excited triplet state and doublet free radicals with diffusion-controlled rate constants. [14][15][16][17][18][19] Other reports of oxygen-independent mechanisms involve the generation of toxic photoproducts from upper excited triplet states, 20 photoinduced electron-transfers leading to cycloaddition reactions, [21][22] and structural changes upon excitation that allow binding to intracellular targets. 10,18 These properties currently preclude therapeutic deployment.…”

Section: Introductionmentioning

confidence: 99%

BODIPY-Based Photothermal Agents with Unprecedented Phototoxic Indices for Cancer Treatment

Schneider

Kalt

Koch

et al. 2022

Preprint

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Here we report six novel, easily accessible BODIPY-based agents for cancer treatment. In contrast to established photodynamic therapy (PDT) agents, these BODIPY-based compounds show additional photothermal activity and their cytotoxicity is not dependent on the generation of reactive oxygen species (ROS). The agents show high photocytotoxicity upon irradiation with light and low dark toxicity in different cancer cell lines in 2D culture as well as in 3D multicellular tumour spheroids (MCTSs). The ratio of dark to light toxicity (phototoxic index, PI) of these agents reaches striking values exceeding 830’000 after irradiation with energetically low doses of light at 630 nm. The oxygen-dependent mechanism of action (MOA) of established photosensitizers (PSs) hampers effective clinical deployment of these agents. Under hypoxic conditions (0.2% O2), which are known to limit the efficiency of conventional PSs in solid tumours, photocytotoxicity was induced at the same concentration levels, indicating an oxygen-independent photothermal MOA. With a PI exceeding 360’000 under hypoxic conditions, both PI values are the highest reported to date. We anticipate that small molecule agents with a photothermal MOA, such as the BODIPY-based compounds reported in this work, may overcome this barrier and provide a new avenue to cancer therapy.

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Molecular and nanoparticulate agents for photodynamic therapy guided by near infrared imaging

Grebinyk,

Chepurna,

Frohme

et al. 2024

Journal of Photochemistry and Photobiology C: Photochemistry Re

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Additional approach to PDT: type III mechanism and the role of native free radicals

Cited by 5 publications

References 0 publications

BODIPY-Based Photothermal Agents with Excellent Phototoxic Indices for Cancer Treatment

BODIPY-Based Photothermal Agents with Excellent Phototoxic Indices for Cancer Treatment

BODIPY-Based Photothermal Agents with Unprecedented Phototoxic Indices for Cancer Treatment

Molecular and nanoparticulate agents for photodynamic therapy guided by near infrared imaging

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