Meta-tetra(hydroxyphenyl)chlorin-sensitized photodynamic damage of cultured tumor and normal cells in the presence of high concentrations of α-tocopherol

Melnikova, Vladislava O.; Bezdetnaya, Lina; Belitchenko, I.; Potapenko, A. Ya.; Merlin, Jean‐Louis; Guillemin, François

doi:10.1016/s0304-3835(99)00023-3

Cited by 33 publications

(28 citation statements)

References 20 publications

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“…Previously, we reported that ␣-tocopherol was incorporated by HT29 cells and, at high concentrations, enhanced their photoinactivation by mTHPC (Melnikova et al, 1999a). Here, we report on the potentiation of PDT of grafted HT29 tumors in mice by the anti-oxidant 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox), a water-soluble analogue of tocopherol.…”

mentioning

confidence: 94%

Enhancement of meta-tetrahydroxyphenylchlorin-sensitized photodynamic treatment on human tumor xenografts using a water-soluble vitamin E analogue, Trolox

Melnikova¹,

Bezdetnaya²,

Brault

et al. 2000

Int. J. Cancer

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mentioning

confidence: 94%

Enhancement of meta-tetrahydroxyphenylchlorin-sensitized photodynamic treatment on human tumor xenografts using a water-soluble vitamin E analogue, Trolox

Melnikova¹,

Bezdetnaya²,

Brault

et al. 2000

Int. J. Cancer

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“…In the case of PDT, some antioxidant molecules are reported to enhance the photodamaging effect of photosensitizer used in photodynamic therapy with various sensitizers and tumor models such as α-Tocopherol (Jakus and Farkas, 2005;Melnikova et al, 1999), Ascorbic acid (Bachowski et al, 1988;Buettner et al, 1993;Girotti et al, 1985;Jakus and Farkas, 2005;Kaliya et al, 1999;Kelley et al, 1997;Rosenthal and Ben-Hur, 1992), water-soluble vitamin E analog, Trolox (Jakus and Farkas, 2005;Melnikova et al, 2000) and BHA (Jakus and Farkas, 2005;. Therefore, few antioxidants can exaggerate the effects of photodynamic therapy with unknown mechanism.…”

Section: Introductionmentioning

confidence: 99%

Quenching of singlet oxygen by natural and synthetic antioxidants and assessment of electronic UV/Visible absorption spectra for alleviating or enhancing the efficacy of photodynamic therapy

2016

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Abstract-Photodynamic therapy (PDT) is one of the methods involved in cancer treatment exploiting singlet oxygen as a weapon to kill cancer cells. Singlet oxygen, a bizarre reactive oxygen species as it is not related to electron transfer to O 2 but it is one of the most active intermediate involved in biochemical reactions as it directly reacts with all the major macromolecules like DNA, protein, lipids etc, various photosensitized oxidations and in the photodegradation of dyes and polymers. Recent studies about the usage of antioxidant along with the photo-sensitizer involved in photodynamic therapy have shown concentration-dependent dual behavior like usually it retards the efficacy of PDT but at a higher dose , it actually enhances the damaging effect of PDT. The natural and synthetic antioxidants are being used in our day to day life in order to increase the shelf life of various food ingredients and processed foods. In this paper, we have compared natural and synthetic antioxidants along with the known singlet oxygen quencher (DABCO) in order to understand the quenching potential of singlet oxygen ( 1 O 2 ) which is lowest electronically excited state of molecular oxygen. The singlet oxygen can be artificially generated through various methods such as sunlight, phosphate, ozonides, NaOCl & H 2 O 2 etc. We have studied the mechanisms of selected antioxidants on the bleaching of RNO linked with the energy decay of 1 O 2 produced by the Mallet reaction (H 2 O 2 + HOCl → HCl + H 2 O + 1 O 2 ). β-Carotene, α-Tocopherol, Ascorbic acid and Quercetin exhibited best dosedependent singlet quenching ranging from 92.3 to 56.5 % at 100μM among others. Overall singlet oxygen is a major concern of light-related properties so we have analyzed the theoretical aspect of electronic UV/visible absorption spectra of the antioxidants studied through ZINDO CI semi-empirical Hamiltonian method. We have compared only the first singlet state of molecules in order to understand whether the structure of the molecules has any influence on the quenching potential. Considering the main features associated with singlet states, we have seen a drastic correlation between known sensitizer of singlet oxygen, i.e. Rose Bengal and DABCO, known scavenger of singlet oxygen in terms of energy and wavelength. This study is important as it highlights the behavior of antioxidant which can improve the effects of photosensitizer used in photodynamic therapy.

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“…Studies have revealed that lycopene (all-trans-lycopene) is one of the most potent antioxidants among major carotenoids (Di Mascio et al, 1989;Stahl et al, 1998), and tomato lycopene extracts have been found to inhibit proliferation of several types of cancer cells (Amir et al, 1999). However, at high concentrations or in the presence of chronic oxidative stress, they can function as pro-oxidants by promoting free radical-induced reactions, and stimulate cell-death machinery (Jakus and Farkas, 2005;Melnikova et al, 1999). In this scenario, it is highly possible that a trace amount of tetracis-lycopene also functions as an antioxidant in plant cells.…”

Section: Discussionmentioning

confidence: 99%

Leaf Variegation in the Rice zebra2 Mutant Is Caused by Photoperiodic Accumulation of Tetra-Cis-Lycopene and Singlet Oxygen

Han

Sakuraba

Koh

et al. 2012

Molecules and Cells

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In field conditions, the zebra2 (z2) mutant in rice (Oryza sativa) produces leaves with transverse pale-green/yellow stripes. It was recently reported that ZEBRA2 encodes carotenoid isomerase (CRTISO) and that low levels of lutein, an essential carotenoid for non-photochemical quenching, cause leaf variegation in z2 mutants. However, we found that the z2 mutant phenotype was completely suppressed by growth under continuous light (CL; permissive) conditions, with concentrations of chlorophyll, carotenoids and chloroplast proteins at normal levels in z2 mutants under CL. ]) accumulated to high levels in z2 mutants grown under short-day conditions (SD; alternate 10-h light/14-h dark; restrictive), but do not accumulate under CL conditions. However, the levels of lutein and zeaxanthin in z2 leaves were much lower than normal in both permissive CL and restrictive SD growth conditions, indicating that deficiency of these two carotenoids is not responsible for the leaf variegation phenotype. We found that the CRTISO substrate tetra-cis-lycopene accumulated during the dark periods under SD, but not under CL conditions. Its accumulation was also positively correlated with 1 O 2 levels generated during the light period, which consequently altered the expression of 1 O 2 -responsive and cell death-related genes in the variegated z2 leaves. Taking these results together, we propose that the z2 leaf variegation can be largely attributed to photoperiodic accumulation of tetra-cis-lycopene and generation of excessive 1 O 2 under natural day-night conditions.

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Meta-tetra(hydroxyphenyl)chlorin-sensitized photodynamic damage of cultured tumor and normal cells in the presence of high concentrations of α-tocopherol

Cited by 33 publications

References 20 publications

Enhancement of meta-tetrahydroxyphenylchlorin-sensitized photodynamic treatment on human tumor xenografts using a water-soluble vitamin E analogue, Trolox

Enhancement of meta-tetrahydroxyphenylchlorin-sensitized photodynamic treatment on human tumor xenografts using a water-soluble vitamin E analogue, Trolox

Quenching of singlet oxygen by natural and synthetic antioxidants and assessment of electronic UV/Visible absorption spectra for alleviating or enhancing the efficacy of photodynamic therapy

Leaf Variegation in the Rice zebra2 Mutant Is Caused by Photoperiodic Accumulation of Tetra-Cis-Lycopene and Singlet Oxygen

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