Photosensitized Oxidation and Singlet Oxygen: Consequences in Biological Systems

Foote, Christopher S.

doi:10.1016/b978-0-12-566502-5.50010-x

Cited by 677 publications

(395 citation statements)

References 258 publications

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“…The spectrum for CPD photolyase activity was different from that for its induction, with a shift to a shorter wavelength range. The activity of CPD photolyase can be induced by treatment with hydrogen peroxide (15), and we found that it was also induced by two photosensitizers, TPPS and ALPS, which produce active oxygen under long-wavelength light (26,27). The photosensitizer ALPS is highly water soluble, whereas TPPS is a lipophilic sensitizer (27).…”

Section: Discussionmentioning

confidence: 90%

Induction of Cyclobutane Pyrimidine Dimer Photolyase in Cultured Fish Cells by UVA and Blue Light

Mikami

Uchida

Shima

1996

Photochem & Photobiology

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The cyclobutane pyrimidine dimer (CPD) photolyase in fish cells is known to be regulated by environmental factors, such as light, hydrogen peroxide and growth inhibition. The induction of CPD photolyase by light in cultured goldfish cells was dependent on the wavelength of the light, and UVA and blue light had high inductive activity. The spectrum for CPD photolyase activity was different from that for the induction. Treatment with blue or yellow light for a short time, which did not induce any CPD photolyase, induced high CPD photolyase activity in the presence of the photosensitizers, TPPS (monosulfonated meso-tetraphenyl porphine) and ALPS (aluminum phthalocyanine tetrasulfonate), respectively. These results suggest that the induction of CPD photolyase might be triggered by active oxygen produced by light and cellular photosensitizers. We also found that immediately after treatment with UVA, blue light or a photosensitizer in combination with light, cellular attachment to the substratum was enhanced, as was the CPD photolyase activity. Pretreatment with a flavonoid, quercetin, inhibited both photoinduction of CPD photolyase and enhancement of cellular attachment. Vitamin E inhibited only photoinduction of CPD photolyase activity.Treatment with H7, a strong inhibitor for protein kinase C, after light treatment inhibited photoinduction of CPD photolyase activity, but an analogue of H7, Ha1004, which is a weak inhibitor of protein kinase C, did not have such an effect.

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Section: Discussionmentioning

confidence: 90%

Induction of Cyclobutane Pyrimidine Dimer Photolyase in Cultured Fish Cells by UVA and Blue Light

Mikami

Uchida

Shima

1996

Photochem & Photobiology

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“…Monomeric phthalocyanines are characterised by long-lived triplet states and high quantum yield of photosensitised generation of activated oxygen species. In particular, GePc appears to perform its photosensitising action largely via the intermediacy of singlet oxygen, as shown by (i) the independence of the photo-oxidation rate constant over a wide range of tryptophan concentrations, while alternative photoreaction pathways involving a direct interaction between the excited photosensitiser and the substrate are concentration dependent (Foote, 1976); and (ii) the almost 40-fold enhancement of the reaction rate in D20-as compared with H20-based media, as one would expect for a predominant singlet oxygen mechanism, since the lifetime of this transient is remarkably longer in deuterated solvents (Gorman & Rodgers, 1992). In spite of its high reactivity in the electronically excited states, GePc undergoes very little photobleaching, which would cause a permanent chemical modification, even under extreme irradiation conditions.…”

Section: Discussionmentioning

confidence: 99%

CGP 55398, a liposomal Ge(IV) phthalocyanine bearing two axially ligated cholesterol moieties: a new potential agent for photodynamic therapy of tumours

Segalla

Milanesi²,

Jori³

et al. 1994

Br J Cancer

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Ge(IV) phthalocyanine (GePc) with two axially ligated cholesterol moieties was prepared by chemical synthesis and incorporated in a monomeric state into small unilamellar liposomes (CGP 55398). Upon photoexcitation with light wavelengths around its intense absorption peak at 680 nm, GePc shows an efficient photosensitising activity towards biological substrates through a mechanism which largely involves the intermediacy of singlet oxygen. GePc injected systemically into mice bearing an intramuscularly implanted MS-2 fibrosarcoma is quantitatively transferred to serum lipoproteins and localises in the tumour tissue with good efficiency: at 24 h post injection the GePc content in the tumour is 0.74 and 1.87 micrograms per g of tissue with a tumour/peritumoral ratio of 4.35 and 5.67 for injected doses of 0.76 and 1.52 mg kg-1 respectively. At this time the red-light irradiation of the GePc-loaded fibrosarcoma causes a fast and massive tumour necrosis involving both malignant cells and blood vessels. Images Figure 8 Figure 9 Figure 10 Figure 11 Figure 12

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“…Virtually all of the molecular components of cell membranes are susceptible to sensitized photomodification by singlet oxygen (Foote, 1976;Spikes and Livingston, 1969). Phospholipids, proteins and cholesterol are all readily oxidized targets, while the carbohydrate moieties of the glycoproteins and glycolipids are not significantly affected.…”

Section: Biochemistry Of Singlet Oxygen Modijication Of Membranesmentioning

confidence: 99%

Photomodification of Biological Membranes With Emphasis on Singlet Oxygen Mechanisms

Valenzeno

1987

Photochem & Photobiology

263

118

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Abstract-This review discusses photomodification of biological membranes and model membrane systems. Current concepts of membrane structure are first reviewed briefly. The role of preillumination association of sensitizer with membranes as it relates to photomodification rate is discussed, as well as the role of singlet oxygen in membrane photomodification. Finally the characteristics of singlet oxygen generation in membranes are considered. The evidence clearly indicates that membrane photomodification cannot be understood based only on the properties of sensitizers and singlet oxygen in aqueous solution. Rather the properties of sensitizers in association with membranes are the determinants of membrane photomodification. These properties differ significantly in aqueous solution and in membranes.

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Photosensitized Oxidation and Singlet Oxygen: Consequences in Biological Systems

Cited by 677 publications

References 258 publications

Induction of Cyclobutane Pyrimidine Dimer Photolyase in Cultured Fish Cells by UVA and Blue Light

Induction of Cyclobutane Pyrimidine Dimer Photolyase in Cultured Fish Cells by UVA and Blue Light

CGP 55398, a liposomal Ge(IV) phthalocyanine bearing two axially ligated cholesterol moieties: a new potential agent for photodynamic therapy of tumours

Photomodification of Biological Membranes With Emphasis on Singlet Oxygen Mechanisms

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