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Taekyu Park - One of the best experts on this subject based on the ideXlab platform.
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The Time‐Dependent Serial Gene Response to Zeocin Treatment Involves Caspase‐Dependent Apoptosis in HeLa Cells
Microbiology and Immunology, 2020Co-Authors: Jooyeon Hwang, Junghee Shim, Chan Park, Kuchan Kimm, Dongkug Choi, Taekyu ParkAbstract:Zeocin, a member of the bleomycin/phleomycin family of antibiotics, is known to bind DNA and to induce apoptosis in cervical cancer cells, but the mechanism underlying this apoptotic response is poorly understood. The present study was undertaken to elucidate time-dependent serial transcript patterns in the HeLa cervical carcinoma cell line, following treatment with Zeocin. The HeLa cell proliferation rate was found to gradually decrease following Zeocin exposure, in a time- and dose-dependent manner. RNA transcript level measurements, for time-dependent serial gene expression profiling, were determined at 0, 6, 12, 18 and 24 hr using a 0.5 k apoptosis functional microarray chip. Further statistical analysis, using a significance test at a 95% confidence level, for transcripts with a greater than 2-fold change on the array chips, identified 49 up-regulated and 57 down-regulated genes. Our gene expression profile data indicate that Zeocin treatment induces an initial release of cytochrome c, the down-regulation of Bcl-XL, ENDOG, DAXX and MDM2, and the up-regulation of CASP and BID. This suggests that a p53-independent mitochondrial caspase cascade pathway is primarily involved in Zeocin-induced apoptosis. Such caspase-dependent cytotoxic activity also implies that this cell death pathway occurs via the caspase 8 and BID genes. However, disruption of either FAS or TNFR1 signaling did not interfere with the Zeocin induced apoptotic response in our experimental system. We hypothesize that Zeocin could be active against cervical cancer cell resistance to conventional chemotherapy and postulate that Zeocin is a novel candidate for the development of new chemotherapeutic treatments of gynecological cancers.
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the time dependent serial gene response to Zeocin treatment involves caspase dependent apoptosis in hela cells
Microbiology and Immunology, 2005Co-Authors: Jooyeon Hwang, Junghee Shim, Chan Park, Kuchan Kimm, Dongkug Choi, Taekyu ParkAbstract:Zeocin, a member of the bleomycin/phleomycin family of antibiotics, is known to bind DNA and to induce apoptosis in cervical cancer cells, but the mechanism underlying this apoptotic response is poorly understood. The present study was undertaken to elucidate time-dependent serial transcript patterns in the HeLa cervical carcinoma cell line, following treatment with Zeocin. The HeLa cell proliferation rate was found to gradually decrease following Zeocin exposure, in a time- and dose-dependent manner. RNA transcript level measurements, for time-dependent serial gene expression profiling, were determined at 0, 6, 12, 18 and 24 hr using a 0.5 k apoptosis functional microarray chip. Further statistical analysis, using a significance test at a 95% confidence level, for transcripts with a greater than 2-fold change on the array chips, identified 49 up-regulated and 57 down-regulated genes. Our gene expression profile data indicate that Zeocin treatment induces an initial release of cytochrome c, the down-regulation of Bcl-XL, ENDOG, DAXX and MDM2, and the up-regulation of CASP and BID. This suggests that a p53-independent mitochondrial caspase cascade pathway is primarily involved in Zeocin-induced apoptosis. Such caspase-dependent cytotoxic activity also implies that this cell death pathway occurs via the caspase 8 and BID genes. However, disruption of either FAS or TNFR1 signaling did not interfere with the Zeocin induced apoptotic response in our experimental system. We hypothesize that Zeocin could be active against cervical cancer cell resistance to conventional chemotherapy and postulate that Zeocin is a novel candidate for the development of new chemotherapeutic treatments of gynecological cancers.
Stephka Chankova - One of the best experts on this subject based on the ideXlab platform.
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dna susceptibility of saccharomyces cerevisiae to Zeocin depends on the growth phase
International Microbiology, 2019Co-Authors: Teodora Todorova, D Miteva, Stephka ChankovaAbstract:The aim of this study was to evaluate the level of Zeocin-induced double-strand breaks (DSBs) in Saccharomyces cerevisiae cells in a different growth phase, using constant-field gel electrophoresis (CFGE). Saccharomyces cerevisiae diploid strain D7ts1 with enhanced cellular permeability was used. The effects of growth phase and treatment time were evaluated based on Zeocin-induced DSBs, measured by CFGE. Survival assay was also applied. No protoplast isolation was necessary for the detection of DSBs in strain D7ts1. Differences in the response of cells depending on the growth phase were obtained. Cells in exponential growth phase had increased DSB levels only after Zeocin treatment with concentrations equal or higher than 200 μgml−1. Increasing treatment time did not result in higher DSB levels. Oppositely, treatment of cells at the beginning of stationary phase with Zeocin concentrations resulted in more than 1.5-fold increase in DSB levels in comparison with those in untreated cells. Increased DSB levels were measured for all the treatment times. A dose-dependent decrease in cell survival was observed after Zeocin treatment with concentrations in the range of lethality LD20–LD50. A strong negative correlation was calculated between the levels of DSBs and cell survival. New information is provided concerning DNA susceptibility depending on the growth phase. DNA susceptibility is higher in cells at the beginning of stationary phase than those in exponential phase. Data presented here illustrate that the optimized by us CFGE protocol is sensitive and could be used successfully for DSB measurement in Saccharomyces cerevisiae strains with enhanced cellular permeability.
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extract of lillium candidum l can modulate the genotoxicity of the antibiotic Zeocin
Molecules, 2011Co-Authors: Marcela Kopaskova, Peter E Bryant, Eva Miadokova, Eliska Galova, Lina Hadjo, Bisera Yankulova, Gabriele Jovtchev, Andrea Sevcovicova, Pavel Mucaji, Stephka ChankovaAbstract:Lilium candidum L. extract (LE) is well known in folk medicine for the treatment of burns, ulcers, inflammations and for healing wounds. This work aims to clarify whether the genotoxic potential of the radiomimetic antibiotic Zeocin (Zeo) could be modulated by LE. Our results indicate that LE exerts no cytotoxic, DNA-damaging and clastogenic activity in in Chlamydomonas reinhardtii, Pisum sativum L. and Hordeum vulgare L. test systems over a broad concentration range. Weak but statistically significant clastogenic effects due to the induction of micronuclei and chromosome aberrations have been observed in H. vulgare L. after treatment with 200 and 300 μg/mL LE. To discriminate protective from adverse action of LE different experimental designs have been used. Our results demonstrate that the treatment with mixtures of LE and Zeo causes an increase in the level of DNA damage, micronuclei and “metaphases with chromatid aberrations” (MwA). Clear evidence has been also obtained indicating that pretreatment with LE given 4 h before the treatment with Zeo accelerates the rejoining kinetics of Zeo-induced DNA damage in P. sativum L. and C. reinhardtii, and can decrease clastogenic effect of Zeo measured as frequencies of micronuclei and MwA in H. vulgare L. Here, we show for the first time that LE can modulate the genotoxic effects of Zeocin. The molecular mode of action strongly depends on the experimental design and varies from synergistic to protective effect (adaptive response–AR). Our results also revealed that LE-induced AR to Zeocin involves up-regulation of DSB rejoining in C. reinhardtii and P. sativum L. cells.
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does single dose cell resistance to the radio mimetic Zeocin correlate with a Zeocin induced adaptive response in chlamydomonas reinhardtii strains
Radiation and Environmental Biophysics, 2009Co-Authors: Evgeniya G Dimova, Maria Dimitrova, D Miteva, Zhana Mitrovska, Nadezhda P Yurina, Peter E Bryant, Stephka ChankovaAbstract:This study aimed to test whether a correlation exists between single-dose resistance to Zeocin and the ability to develop a Zeocin-induced adaptive response (AR) in Chlamydomonas reinhardtii strains. Three genotypes were used: wild type (WT) strain 137C and two strains (H-3 and AK-9-9), which are highly resistant to radiation based on survival studies. Based on a micro-colony assay, the strains could be arranged according to their single-dose resistance to Zeocin as follows: AK-9-9 > H-3 > 137C. However, Zeocin induced a similar level of DSB in strains AK-9-9, H-3 and 137C. The radio- and Zeocin-resistant strains AK-9-9 and H-3 showed higher DSB rejoining capacity than the WT strain 137C, suggesting that DSB rejoining can at least partly account for different cell survival. Both WT and radio-resistant strains develop Zeocin-induced AR involving increased DSB rejoining. The radio- and Zeocin-resistant strains AK-9-9 and H-3 again showed higher DSB rejoining capacity than the WT strain 137C. The higher resistance of strains H-3 and AK-9-9 did not abrogate their ability to adapt, albeit with a smaller magnitude as compared to the WT strain. The obtained results characterize new radio-resistant C. reinhardtii strains, which enrich the collection of resistant C. reinhardtii strains.
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induction of dna double strand breaks by Zeocin in chlamydomonas reinhardtii and the role of increased dna double strand breaks rejoining in the formation of an adaptive response
Radiation and Environmental Biophysics, 2007Co-Authors: Stephka Chankova, Evgeniya G Dimova, Maria Dimitrova, Peter E BryantAbstract:This study aimed to test the potential of the radiomimetic chemical Zeocin to induce DNA double-strand breaks (DSB) and “adaptive response” (AR) in Chlamydomonas reinhardtii strain CW15 as a model system. The AR was measured as cell survival using a micro-colony assay, and by changes in rejoining of DSB DNA. The level of induced DSB was measured by constant field gel electrophoresis based on incorporation of cells into agarose blocks before cell lysis. This avoids the risk of accidental induction of DSB during the manipulation procedures. Our results showed that Zeocin could induce DSB in C. reinhardtii strain CW15 in a linear dose-response fashion up to 100 μg ml−1 which marked the beginning of a plateau. The level of DSB induced by 100 μg ml−1 Zeocin was similar to that induced by 250 Gy of gamma-ray irradiation. It was also found that, similar to gamma rays, Zeocin could induce AR measured as DSB in C. reinhardtii CW15 and this AR involved acceleration of the rate of DSB rejoining, too. To our knowledge, this is the first demonstration that Zeocin could induce AR in some low eukaryotes such as C. reinhardtii.
Florence Larminat - One of the best experts on this subject based on the ideXlab platform.
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resistance to the antibiotic Zeocin by stable expression of the sh ble gene does not fully suppress Zeocin induced dna cleavage in human cells
Mutagenesis, 2005Co-Authors: Manel Oliva Trastoy, M Defais, Florence LarminatAbstract:Zeocin is a member of the bleomycin/phleomycin family of antibiotics, known to bind and cleave DNA. We established human SK-OV-3 cells that stably express the Zeocin resistance gene (Sh ble) using an ecdysone-inducible mammalian expression system. Surprisingly, our results demonstrated that Zeocin, added in the culture medium to maintain the expression of the ecdysone receptor, was responsible for the formation of DNA strand breaks in the recombinant cells. This suggests that the Zeocin is not completely detoxified and is still able to cleave DNA, despite the stable expression of the Sh ble gene in the recombinant clones. Our study indicates that one needs to be very cautious in the interpretation of data involving stable cell lines selected with Zeocin.
Jooyeon Hwang - One of the best experts on this subject based on the ideXlab platform.
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The Time‐Dependent Serial Gene Response to Zeocin Treatment Involves Caspase‐Dependent Apoptosis in HeLa Cells
Microbiology and Immunology, 2020Co-Authors: Jooyeon Hwang, Junghee Shim, Chan Park, Kuchan Kimm, Dongkug Choi, Taekyu ParkAbstract:Zeocin, a member of the bleomycin/phleomycin family of antibiotics, is known to bind DNA and to induce apoptosis in cervical cancer cells, but the mechanism underlying this apoptotic response is poorly understood. The present study was undertaken to elucidate time-dependent serial transcript patterns in the HeLa cervical carcinoma cell line, following treatment with Zeocin. The HeLa cell proliferation rate was found to gradually decrease following Zeocin exposure, in a time- and dose-dependent manner. RNA transcript level measurements, for time-dependent serial gene expression profiling, were determined at 0, 6, 12, 18 and 24 hr using a 0.5 k apoptosis functional microarray chip. Further statistical analysis, using a significance test at a 95% confidence level, for transcripts with a greater than 2-fold change on the array chips, identified 49 up-regulated and 57 down-regulated genes. Our gene expression profile data indicate that Zeocin treatment induces an initial release of cytochrome c, the down-regulation of Bcl-XL, ENDOG, DAXX and MDM2, and the up-regulation of CASP and BID. This suggests that a p53-independent mitochondrial caspase cascade pathway is primarily involved in Zeocin-induced apoptosis. Such caspase-dependent cytotoxic activity also implies that this cell death pathway occurs via the caspase 8 and BID genes. However, disruption of either FAS or TNFR1 signaling did not interfere with the Zeocin induced apoptotic response in our experimental system. We hypothesize that Zeocin could be active against cervical cancer cell resistance to conventional chemotherapy and postulate that Zeocin is a novel candidate for the development of new chemotherapeutic treatments of gynecological cancers.
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the time dependent serial gene response to Zeocin treatment involves caspase dependent apoptosis in hela cells
Microbiology and Immunology, 2005Co-Authors: Jooyeon Hwang, Junghee Shim, Chan Park, Kuchan Kimm, Dongkug Choi, Taekyu ParkAbstract:Zeocin, a member of the bleomycin/phleomycin family of antibiotics, is known to bind DNA and to induce apoptosis in cervical cancer cells, but the mechanism underlying this apoptotic response is poorly understood. The present study was undertaken to elucidate time-dependent serial transcript patterns in the HeLa cervical carcinoma cell line, following treatment with Zeocin. The HeLa cell proliferation rate was found to gradually decrease following Zeocin exposure, in a time- and dose-dependent manner. RNA transcript level measurements, for time-dependent serial gene expression profiling, were determined at 0, 6, 12, 18 and 24 hr using a 0.5 k apoptosis functional microarray chip. Further statistical analysis, using a significance test at a 95% confidence level, for transcripts with a greater than 2-fold change on the array chips, identified 49 up-regulated and 57 down-regulated genes. Our gene expression profile data indicate that Zeocin treatment induces an initial release of cytochrome c, the down-regulation of Bcl-XL, ENDOG, DAXX and MDM2, and the up-regulation of CASP and BID. This suggests that a p53-independent mitochondrial caspase cascade pathway is primarily involved in Zeocin-induced apoptosis. Such caspase-dependent cytotoxic activity also implies that this cell death pathway occurs via the caspase 8 and BID genes. However, disruption of either FAS or TNFR1 signaling did not interfere with the Zeocin induced apoptotic response in our experimental system. We hypothesize that Zeocin could be active against cervical cancer cell resistance to conventional chemotherapy and postulate that Zeocin is a novel candidate for the development of new chemotherapeutic treatments of gynecological cancers.
James P Hoeffler - One of the best experts on this subject based on the ideXlab platform.
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fusion of green fluorescent protein with the Zeocin resistance marker allows visual screening and drug selection of transfected eukaryotic cells
BioTechniques, 1998Co-Authors: Robert P Bennett, James P HoefflerAbstract:Green fluorescent protein (GFP) and the Zeocin™-resistance gene Sh ble (ZeoR) were fused together to generate a bifunctional protein for the identification and selection of transfected mammalian cells. Expression of this hybrid selectable marker, GFP-ZeoR, was visually detected and conferred Zeocin resistance in prokaryotes and eukaryotes. This selectable marker provides a way to determine transient transfection efficiencies in tissue culture cells using fluorescence microscopy. Expression of the GFP-ZeoR was also used to identify and select stable mammalian cell lines expressing a heterologous gene. Selection was efficient and GFP fluorescence provides an excellent, noninvasive technique to monitor the success of Zeocin selection during the development of the stable cell lines. This hybrid resistance gene combines the functional properties of the Zeocin-resistance marker and GFP and should be useful for combined selection and fluorescence in a variety of organisms.
