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Journal of Applied Biomedicine Oct 2022Breast cancer is a serious public problem in modern society. Photodynamic therapy (PDT) is increasingly used in modern medicine. Currently, PDT is an innovative method... (Review)
Review
Breast cancer is a serious public problem in modern society. Photodynamic therapy (PDT) is increasingly used in modern medicine. Currently, PDT is an innovative method of treating breast cancer. Irreversible damage to neoplastic tissues is associated with the use of physicochemical processes. Generating cytotoxic reactive oxygen species [singlet oxygen (1O2)] is leading to tumor cell death. At the same time, valuable information can be extracted from breast cancer cells. Photogenerated 1O2 is the major factor responsible for cell necrosis during PDT. 1O2 can react rapidly intracellularly with all organic substances. The use of photodynamic therapy on tissues in vitro creates conditions for testing various types of solutions and implementing them in in vivo treatment. This article is a review of recent advances in PDT for treatment of breast cancer. PDT is a novel cancer diagnostic and cancer treatment therapy. Therefore, an understanding of the possibility to generate a toxic form of 1O2 is necessary. The knowledge gained from the basics of PDT in vitro can be useful in biomedical applications in vivo. The current literature mentions PDT in the treatment of cancers located very deep within the human body. Therefore, the development of agents used to deliver 1O2 to the deep cancerous tissue is a new challenge which can have an efficient impact on this discipline. This review covers the literature between 2000-2022.
Topics: Breast Neoplasms; Female; Humans; Photochemotherapy; Reactive Oxygen Species; Singlet Oxygen
PubMed: 36218130
DOI: 10.32725/jab.2022.013 -
Photochemistry and Photobiology Nov 2021Metal thiolate complexes can act as photosensitizers for the generation of singlet oxygen, quenchers of singlet oxygen, and they may undergo chemical reactions with... (Review)
Review
Metal thiolate complexes can act as photosensitizers for the generation of singlet oxygen, quenchers of singlet oxygen, and they may undergo chemical reactions with singlet oxygen leading to oxidized thiolate ligands. This review covers all of the chemical reactions of thiolate ligands with singlet oxygen (through early 2021). Since some of these reactions are self-sensitized photooxidations, singlet oxygen generation by metal complexes is also discussed. Mechanistic features such as the effects of protic vs. aprotic conditions are presented and compared with the comparatively well-understood photooxidation of organic sulfides. In general, the total rate of singlet oxygen removal correlates with the nucleophilicity of the thiolate ligand which in turn can be influenced by the metal. Some interesting patterns of reactivity have been noted as a result of this survey: Metal thiolate complexes bearing arylthiolate ligands appear to exclusively produce sulfinate (metal-bound sulfone) products upon reaction with singlet oxygen. In contrast, metal thiolate complexes bearing alkylthiolate ligands may produce sulfinate and/or sulfenate (metal-bound sulfoxide) products. Several mechanistic pathways have been proposed for these reactions, but the exact nature of any intermediates remains unknown at this time.
Topics: Ligands; Metals; Oxygen; Photosensitizing Agents; Singlet Oxygen
PubMed: 34242405
DOI: 10.1111/php.13487 -
Chembiochem : a European Journal of... Jan 2021Singlet oxygen is a reactive oxygen species undesired in living cells but a rare and valuable reagent in chemical synthesis. We present a fluorescence spectroscopic...
Singlet oxygen is a reactive oxygen species undesired in living cells but a rare and valuable reagent in chemical synthesis. We present a fluorescence spectroscopic analysis of the singlet-oxygen formation activity of commercial peroxidases and novel peroxygenases. Singlet-oxygen sensor green (SOSG) is used as fluorogenic singlet oxygen trap. Establishing a kinetic model for the reaction cascade to the fluorescent SOSG endoperoxide permits a kinetic analysis of enzymatic singlet-oxygen formation. All peroxidases and peroxygenases show singlet-oxygen formation. No singlet oxygen activity could be found for any catalase under investigation. Substrate inhibition is observed for all reactive enzymes. The commercial dye-decolorizing peroxidase industrially used for dairy bleaching shows the highest singlet-oxygen activity and the lowest inhibition. This enzyme was immobilized on a textile carrier and successfully applied for a chemical synthesis. Here, ascaridole was synthesized via enzymatically produced singlet oxygen.
Topics: Fluorescent Dyes; Mixed Function Oxygenases; Molecular Structure; Peroxidases; Singlet Oxygen
PubMed: 32798264
DOI: 10.1002/cbic.202000326 -
International Journal of Molecular... May 2020Singlet oxygen (O) refers to the lowest excited electronic state of molecular oxygen. It easily oxidizes biological molecules and, therefore, is cytotoxic. In plant... (Review)
Review
Singlet oxygen (O) refers to the lowest excited electronic state of molecular oxygen. It easily oxidizes biological molecules and, therefore, is cytotoxic. In plant cells, O is formed mostly in the light in thylakoid membranes by reaction centers of photosystem II. In high concentrations, O destroys membranes, proteins and DNA, inhibits protein synthesis in chloroplasts leading to photoinhibition of photosynthesis, and can result in cell death. However, O also acts as a signal relaying information from chloroplasts to the nucleus, regulating expression of nuclear genes. In spite of its extremely short lifetime, O can diffuse from the chloroplasts into the cytoplasm and the apoplast. As shown by recent studies, O-activated signaling pathways depend not only on the levels but also on the sites of O production in chloroplasts, and can activate two types of responses, either acclimation to high light or programmed cell death. O can be produced in high amounts also in root cells during drought stress. This review summarizes recent advances in research on mechanisms and sites of O generation in plants, on O-activated pathways of retrograde- and cellular signaling, and on the methods to study O production in plants.
Topics: Apoptosis; Chloroplasts; Oxidative Stress; Signal Transduction; Singlet Oxygen
PubMed: 32375245
DOI: 10.3390/ijms21093237 -
International Journal of Molecular... Dec 2022Broad antiviral activity in vitro is known for many organic photosensitizers generating reactive oxygen species under irradiation with visible light. Low tissue... (Review)
Review
Broad antiviral activity in vitro is known for many organic photosensitizers generating reactive oxygen species under irradiation with visible light. Low tissue penetration of visible light prevents further development of antiviral therapeutics based on these compounds. One possible solution to this problem is the development of photosensitizers with near-infrared absorption (NIR dyes). These compounds found diverse applications in the photodynamic therapy of tumors and bacterial infections, but they are scarcely mentioned as antivirals. In this account, we aimed to evaluate the therapeutic prospects of various NIR-absorbing and singlet oxygen-generating chromophores for the development of broad-spectrum photosensitizing antivirals.
Topics: Photosensitizing Agents; Coloring Agents; Antiviral Agents; Infrared Rays; Photochemotherapy; Singlet Oxygen
PubMed: 36613629
DOI: 10.3390/ijms24010188 -
Acta Biochimica Polonica 2012The dietary carotenoids provide photoprotection to photosynthetic organisms, the eye and the skin. The protection mechanisms involve both quenching of singlet oxygen and... (Review)
Review
The dietary carotenoids provide photoprotection to photosynthetic organisms, the eye and the skin. The protection mechanisms involve both quenching of singlet oxygen and of damaging free radicals. The mechanisms for singlet oxygen quenching and protection against free radicals are quite different - indeed, under some conditions, quenching of free radicals can lead to a switch from a beneficial anti-oxidant process to damaging pro-oxidative situation. Furthermore, while skin protection involves β-carotene or lycopene from a tomato-rich diet, protection of the macula involves the hydroxyl-carotenoids (xanthophylls) zeaxanthin and lutein. Time resolved studies of singlet oxygen and free radicals and their interaction with carotenoids via pulsed laser and fast electron spectroscopy (pulse radiolysis) and the possible involvement of amino acids are discussed and used to (1) speculate on the anti- and pro-oxidative mechanisms, (2) determine the most efficient singlet oxygen quencher and (3) demonstrate the benefits to photoprotection of the eye from the xanthophylls rather than from hydrocarbon carotenoids such as β-carotene.
Topics: Antioxidants; Carotenoids; Food; Free Radicals; Humans; Oxidation-Reduction; Singlet Oxygen
PubMed: 22428151
DOI: No ID Found -
Free Radical Biology & Medicine Nov 2018Oxidants play an important role in the cell and are involved in many redox processes. Oxidant concentrations are maintained through coordinated production and removal... (Review)
Review
Oxidants play an important role in the cell and are involved in many redox processes. Oxidant concentrations are maintained through coordinated production and removal systems. The dysregulation of oxidant homeostasis is a hallmark of many disease pathologies. The local oxidant microdomain is crucial for the initiation of many redox signaling events; however, methods to control oxidant product are limited. Some fluorescent proteins, including GFP, TagRFP, KillerRed, miniSOG, and their derivatives, generate oxidants in response to light. These genetically-encoded photosensitizers produce singlet oxygen and superoxide upon illumination and offer spatial and temporal control over oxidant production. In this review, we will examine the photosensitization properties of fluorescent proteins and their application to redox biology. Emerging concepts of selective oxidant species production via photosensitization and the impact of light on biological systems are discussed.
Topics: Animals; Humans; Light; Luminescent Proteins; Oxidants; Singlet Oxygen
PubMed: 29425690
DOI: 10.1016/j.freeradbiomed.2018.02.002 -
International Journal of Molecular... Feb 2023Reactive oxygen species, including singlet oxygen, play an important role in the onset and progression of disease, as well as in aging. Singlet oxygen can be formed... (Review)
Review
Reactive oxygen species, including singlet oxygen, play an important role in the onset and progression of disease, as well as in aging. Singlet oxygen can be formed non-enzymatically by chemical, photochemical, and electron transfer reactions, or as a byproduct of endogenous enzymatic reactions in phagocytosis during inflammation. The imbalance of antioxidant enzymes and antioxidant networks with the generation of singlet oxygen increases oxidative stress, resulting in the undesirable oxidation and modification of biomolecules, such as proteins, DNA, and lipids. This review describes the molecular mechanisms of singlet oxygen production in vivo and methods for the evaluation of damage induced by singlet oxygen. The involvement of singlet oxygen in the pathogenesis of skin and eye diseases is also discussed from the biomolecular perspective. We also present our findings on lipid oxidation products derived from singlet oxygen-mediated oxidation in glaucoma, early diabetes patients, and a mouse model of bronchial asthma. Even in these diseases, oxidation products due to singlet oxygen have not been measured clinically. This review discusses their potential as biomarkers for diagnosis. Recent developments in singlet oxygen scavengers such as carotenoids, which can be utilized to prevent the onset and progression of disease, are also described.
Topics: Animals; Mice; Singlet Oxygen; Antioxidants; Reactive Oxygen Species; Oxidative Stress; Oxidation-Reduction; Oxygen
PubMed: 36769060
DOI: 10.3390/ijms24032739 -
Molecules (Basel, Switzerland) Jul 2019The synthesis and application of porphyrins has seen a huge shift towards research in porphyrin bio-molecular based systems in the past decade. The preferential... (Review)
Review
The synthesis and application of porphyrins has seen a huge shift towards research in porphyrin bio-molecular based systems in the past decade. The preferential localization of porphyrins in tumors, as well as their ability to generate reactive singlet oxygen and low dark toxicities has resulted in their use in therapeutic applications such as photodynamic therapy. However, their inherent lack of bio-distribution due to water insolubility has shifted research into porphyrin-nanomaterial conjugated systems to address this challenge. This has broadened their bio-applications, viz. bio-sensors, fluorescence tracking, in vivo magnetic resonance imaging (MRI), and positron emission tomography (PET)/CT imaging to photo-immuno-therapy just to highlight a few. This paper reviews the unique theranostic role of porphyrins in disease diagnosis and therapy. The review highlights porphyrin conjugated systems and their applications. The review ends by bringing current challenges and future perspectives of porphyrin based conjugated systems and their respective applications into light.
Topics: Animals; Glycoconjugates; Humans; Magnetic Resonance Imaging; Mice; Neoplasms; Photochemotherapy; Photosensitizing Agents; Porphyrins; Positron-Emission Tomography; Singlet Oxygen; Theranostic Nanomedicine; Water
PubMed: 31340553
DOI: 10.3390/molecules24142669 -
Eye (London, England) Nov 2021To evaluate the singlet oxygen (O) production of oxygen assisted %0.1 riboflavin and ultraviolet-A (UVA) crosslinking therapy (with and without oxygen assistance), in...
BACKGROUND
To evaluate the singlet oxygen (O) production of oxygen assisted %0.1 riboflavin and ultraviolet-A (UVA) crosslinking therapy (with and without oxygen assistance), in combination with standard, accelerated and hyper-accelerated procedures via an important quantitive marker of O which is the photo-oxidation of 1,3 diphenylisobenzofuran (DPBF).
METHODS
%0.1 riboflavin-containing wells were irradiated with UVA light (365-nm wavelength) with or without 2-4-6-8 L/min oxygen flow assistance. Measurements of decrease in absorbance of DPBF were made in 30 mW (hyper-accelerated), 9 mW (accelerated), and 3 mW UV-A (standard) applications, and with additional 2-4-6-8 L/min oxygen flow in 30 mW and 2 L/min oxygen flow in 9 mW. A total of 8 different UV-A irradiance with and without oxygen supplementation groups were formed.
RESULTS
2 L/min oxygen assisted accelerated UV-A irradiance group has shown a greater decrease in DPBF absorbance compared to Dresden protocol. (p = 0.014) Also, Dresden protocol has shown a greater decrease in DPBF compared to all groups except accelerated crosslinking with 2 L/min oxygen. (p < 0.001) Oxygen assisted hyper-accelerated crosslinking groups were showed greater reduction in DPBF absorbance compared to standard crosslinking without oxygen groups. (p < 0.001).
CONCLUSION
Oxygen supplementation may increase the singlet oxygen generation to the similar levels of Dresden Protocol's in accelerated group. Also, more singlet oxygen generation with oxygen supplementation compared to standard UV-A application might be considered to be promising in terms of shortening the crosslinking therapy.
Topics: Collagen; Cross-Linking Reagents; Humans; Keratoconus; Photochemotherapy; Photosensitizing Agents; Singlet Oxygen
PubMed: 34363049
DOI: 10.1038/s41433-021-01731-7