Aphidicolin inhibits excision repair of UV-induced pyrimidine photodimers in low serum cultures of mitotic and mitomycin C-induced postmitotic human skin fibroblasts

Niggli, Hugo J.

doi:10.1016/0921-8734(93)90014-t

Cited by 9 publications

(5 citation statements)

References 38 publications

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“…Passages between 3-10 and 15-25, respectively, were used. Postmitotic fibroblasts were prepared as previously described (24)(25)(26). Keratinocytes were grown on 3T3 feeder layers and passaged 1 : I0 and for UVA experiments transferred to serum-free medium (Gibco, keratinocytes SFM, Basel, Switzerland) essentially as described before (3 1) and used between passages 3 and 10.…”

Section: Methodsmentioning

confidence: 99%

“…Using this system, we were able to demonstrate that no significant difference exists in the rate and the extent of the excision-repair response to thymine-containing pyrimidine dimers following UV irradiation shortly after mitomycin C treatment of distinct strains of human skin fibroblasts and in the mitomycin C-induced PMF stage of these cells (24). although aphidicolin efficiently inhibits excision repair of these UV-induced photoproducts (25).…”

Section: Introductionmentioning

confidence: 98%

“…Additionally, they developed methods to shorten the transition period and to increase the frequency of distinct postmitotic cell types using physical or chemical agents (e.g. mitomycin c, 5-fluorouracil and 5-bromo-2-deoxyuridine) (24)(25)(26). Mitomycin C is an effective chemotherapeutic agent for several cancers in humans; this effect is probably related to the interaction with DNA leading to DNA-DNA crosslinks and DNA-protein crosslinks.…”

Section: Introductionmentioning

confidence: 99%

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Glutathione Response after UVA Irradiation in Mitotic and Postmitotic Human Skin Fibroblasts and Keratinocytes

Niggli¹,

Applegate²

1997

Photochem & Photobiology

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Since Hayflick's pioneering work in the early sixties, human diploid fibroblasts have become a widely accepted in vitro model system. Recently, Bayreuther and co-workers extended this experimental approach showing that fibroblasts in culture resemble, in their design, the hemopoietic stem-cell differentiation system. They found that the chemical agent mitomycin C accelerates the differentiation pathway from mitotic to postmitotic fibroblasts. We measured the response of endogenous glutathione levels after UVA irradiation (320-400 nm) in mitotic and mitomycin C-induced postmitotic human skin fibroblasts and foreskin-derived keratinocytes. The initial levels in mitotic foreskin derived human fibroblasts were 14.4 nmol glutathione per mg protein, whereas a 30% higher value was obtained in matching foreskin-derived keratinocytes. Similar elevated levels of this important intracellular free radical scavenging system were found in fibroblasts of a donor suffering from xeroderma pigmentosum. Furthermore, three to four times higher levels of glutathione in mitomycin C-treated mitotic fibroblasts have been determined. In mitotic skin fibroblasts, UVA irradiation resulted in a depletion of glutathione up to 90% following a fluence of 1.0 MJ/m2 UVA radiation. Higher initial glutathione levels were found in keratinocytes and mitomycin C-treated skin fibroblasts. In these fibroblasts a 70% depletion was detected and a much lower depletion (10-20%) was seen in some keratinocyte cell lines following fluences up to 1.0 MJ/m2. The depletion in skin fibroblasts was retained after 24 h following a fluence of 0.75 MJ/m2 UVA light. In view of the fact that glutathione has been shown to be involved in a variety of metabolic processes and plays a role in cellular protection against UVA radiation, our results imply that the fibroblast differentiation system is a very useful tool to unravel the complex mechanism of UVA-induced oxidative stress.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

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Glutathione Response after UVA Irradiation in Mitotic and Postmitotic Human Skin Fibroblasts and Keratinocytes

Niggli¹,

Applegate²

1997

Photochem & Photobiology

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“…This underlines that DNA strand breaks, in contrast to cyclobutane pyrimidine dimers and (6-4)-photoproducts, are not critical damages for cell survival after UVC-exposure. Dimers and photoproducts themselves are not directly detectable using the FADU assay, their removal from damaged DNA, however, can be detected, especially in the presence of aphidicolin, a potent DNA synthesis inhibitor (33)(34)(35). The FADU clearly permits a distinction between the repairdeficient and -proficient cell line after repair incubation.…”

Section: Discussionmentioning

confidence: 99%

Fluorometric Analysis of DNA Unwinding (FADU) as a Method for Detecting Repair-induced DNA Strand Breaks in UV-irradiated Mammalian Cells¶

Baumstark‐Khan

Hentschel²,

Nikandrova

et al. 2000

Photochem Photobiol

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Fluorometric analysis of DNA unwinding (FADU assay) was originally designed to detect X-ray-induced DNA damage in repair-proficient and repair-deficient mammalian cell lines. The method was modified and applied to detect DNA strand breaks in Chinese hamster ovary (CHO) cells exposed to ionizing radiation as well as to UV light. Exposed cells were allowed to repair damaged DNA by incubation for up to 1 h after exposure under standard growth conditions in the presence and in the absence of the DNA synthesis inhibitor aphidicolin. Thereafter, cell lysates were mixed with 0.15 M sodium hydroxide, and DNA unwinding took place at pH 12.1 for 30 min at 20 degrees C. The amount of DNA remaining double-stranded after alkaline reaction was detected by binding to the Hoechst 33258 dye (bisbenzimide) and measuring the fluorescence. After exposure to X-rays DNA strand breaks were observed in all cell lines immediately after exposure with subsequent restitution of high molecular weight DNA during postexposure incubation. In contrast, after UV exposure delayed production of DNA strand break was observed only in cell lines proficient for nucleotide excision repair of DNA photoproducts. Here strand break production was enhanced when the polymerization step was inhibited by adding the repair inhibitor aphidicolin during repair incubation. These results demonstrate that the FADU approach is suitable to distinguish between different DNA lesions (strand breaks versus base alterations) preferentially induced by different environmental radiations (X-rays versus UV) and to distinguish between the different biochemical processes during damage repair (incision versus polymerization and ligation).

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“…The scientific researchers, the physicist Fritz-Albert Popp and the biologist Yu Yan described this phenomenon twelve years ago as coherent states in biological tissues [6]. In the last years, we developed a cell culture model for biophotonic measurements using fibroblastic differentiation [7][8][9][10][11][12][13][14][15]. An in vivo application of ultraweak radiation on human skin was developed by Cohen and Popp [16] and most recently confirmed by Musumeci and co-workers [17].…”

Section: Introductionmentioning

confidence: 99%

Ultraweak Electromagnetic Wavelength Radiation as Biophotonic Signals to Regulate Life Processes

2014

J Elec Electron Syst

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In recent years the low level analysis of ultra-weak photon emission in human cells is achieved using sophisticated Photomultiplier Technique (PMT). The basis of photonic measurements goes back to the theoretical finding of Einstein that a photon, which hits a metal plate, causes an electrical impulse. This current can be detected by single photon detection device as mentioned before. As shown in a variety of analytical laboratories worldwide using this sensitive workhorse it is evident that all cells from plants over animals up to humans emit a low level biophotonic emission. The measured electromagnetic wavelengths of this miniscule 0.01 Femto Watt (10 -17 W) radiation are ranging from ultraviolet light over the visible up to the infrared region. In order to visualize the size of this very weak light source: the luminous power of a candle in a Lunar Distance (LD) (1 LD equal to 384'400 km) still can be measured using the photomultiplier system mentioned above. From biophotonics investigations so far, the origin of ultra-weak photon emission is the DNA as well as proteins coupled with radical reactions. In order to determine this radiation in human cells, a fibroblastic differentiation system was developed using dermal fibroblasts of skin. Since normal cells store efficiently ultra-weak photons, it has been shown that older cells as well as cancer tissue tend to lose this retention capacity. From all these results it seems evident, that this low level radiation serve as biophotonic signals in order to transfer information in biological systems. Further intense basic research is needed in order to show evidence that ultraweak electromagnetic radiation plays the key role in life.

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Aphidicolin inhibits excision repair of UV-induced pyrimidine photodimers in low serum cultures of mitotic and mitomycin C-induced postmitotic human skin fibroblasts

Cited by 9 publications

References 38 publications

Glutathione Response after UVA Irradiation in Mitotic and Postmitotic Human Skin Fibroblasts and Keratinocytes

Glutathione Response after UVA Irradiation in Mitotic and Postmitotic Human Skin Fibroblasts and Keratinocytes

Fluorometric Analysis of DNA Unwinding (FADU) as a Method for Detecting Repair-induced DNA Strand Breaks in UV-irradiated Mammalian Cells¶

Ultraweak Electromagnetic Wavelength Radiation as Biophotonic Signals to Regulate Life Processes

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