MutagenesisPub Date : 2024-02-01DOI: 10.1093/mutage/geae004
Katherine E Chapman, Ume-Kulsoom Shah, Jessica F Fletcher, George E Johnson, Shareen H Doak, Gareth J S Jenkins
{"title":"An integrated in vitro carcinogenicity test that distinguishes between genotoxic carcinogens, non-genotoxic carcinogens, and non-carcinogens","authors":"Katherine E Chapman, Ume-Kulsoom Shah, Jessica F Fletcher, George E Johnson, Shareen H Doak, Gareth J S Jenkins","doi":"10.1093/mutage/geae004","DOIUrl":"https://doi.org/10.1093/mutage/geae004","url":null,"abstract":"Chemical safety testing plays a crucial role in product and pharmacological development, as well as chemoprevention; however, in vitro genotoxicity safety tests do not always accurately predict the chemicals that will be in vivo carcinogens. If chemicals test positive in vitro for genotoxicity but negative in vivo, this can contribute to unnecessary testing in animals used to confirm erroneous in vitro positive results. Current in vitro tests typically evaluate only genotoxicity endpoints, which limits their potential to detect non-genotoxic carcinogens. The frequency of misleading in vitro positive results can be high, leading to a requirement for more informative in vitro tests. It is now recognised that multiple-endpoint genotoxicity testing may aid more accurate detection of carcinogens and non-carcinogens. The objective of this review was to evaluate the utility of our novel, multiple-endpoint in vitro test which uses multiple cancer-relevant endpoints to predict carcinogenic potential. The tool assessed micronucleus frequency, p53 expression, p21 expression, mitochondrial respiration, cell cycle abnormalities and, uniquely, cell morphology changes in human lymphoblastoid cell lines, TK6 and MCL-5. The endpoints were used to observe cellular responses to 18 chemicals within the following categories: genotoxic carcinogens, non-genotoxic carcinogens, toxic non-carcinogens, and misleading in vitro positive and negative agents. The number of endpoints significantly altered for each chemical was considered, alongside the holistic Integrated Signature of Carcinogenicity score, derived from the sum of fold changes for all endpoints. Following calculation of an overall score from these measures, carcinogens exhibited greater potency than non-carcinogens. Genotoxic carcinogens were generally more potent than non-genotoxic carcinogens. This novel approach therefore demonstrated potential for correctly predicting whether chemicals with unknown mechanism may be considered carcinogens. Overall, while further validation is recommended, the test demonstrates potential for identification of carcinogenic compounds. Adoption of the approach could enable reduced animal use in carcinogenicity testing.","PeriodicalId":18889,"journal":{"name":"Mutagenesis","volume":"27 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139663858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
MutagenesisPub Date : 2023-12-19DOI: 10.1093/mutage/gead027
Hao Zhou, Fang Wang
{"title":"Tensin 1 regulated by hepatic leukemia factor represses the progression of prostate cancer.","authors":"Hao Zhou, Fang Wang","doi":"10.1093/mutage/gead027","DOIUrl":"10.1093/mutage/gead027","url":null,"abstract":"<p><p>Hepatic leukemia factor (HLF), a transcription factor, is dysregulated in many cancers. This study investigates the function of HLF in prostate cancer (PCa) and its relation to tensin 1 (TNS1). Clinical tissues were collected from 24 PCa patients. Duke University 145 (DU145) and PC3 cells overexpressing HLF were established. HLF signaling was downregulated in PCa tissues compared to adjacent tissues and in DU145 and PC3 cells compared to prostate epithelial cells RWPE-1 or prostate stromal cells (WPMY-1). PCa cell lines with overexpression of HLF had reduced proliferative, migratory, and invasive activity, increased apoptosis, and cell mitosis mostly in the G0/G1 phase. HLF induced the TNS1 transcription to activate the p53 pathway. Depletion of TNS1 reversed the anti-tumor effects of HLF on PCa cells and tumor growth and metastasis in vivo. In summary, our findings suggest that HLF suppressed PCa progression by upregulating TNS1 expression and inducing the p53 pathway activation, which might provide insights into novel strategies for combating PCa.</p>","PeriodicalId":18889,"journal":{"name":"Mutagenesis","volume":" ","pages":"295-304"},"PeriodicalIF":2.7,"publicationDate":"2023-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10235416","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
MutagenesisPub Date : 2023-12-19DOI: 10.1093/mutage/gead029
Varinderpal S Dhillon, Permal Deo, Michael Fenech
{"title":"Effect of iron and calcium on radiation sensitivity in prostate cancer patients relative to controls.","authors":"Varinderpal S Dhillon, Permal Deo, Michael Fenech","doi":"10.1093/mutage/gead029","DOIUrl":"10.1093/mutage/gead029","url":null,"abstract":"<p><p>High intake of red meat and/or dairy products may increase the concentration of iron and calcium in plasma-a risk factor for prostate cancer (PC). Despite our understandings of nutrients and their effects on the genome, studies on the effects of iron and calcium on radiation sensitivity of PC patients are lacking. Therefore, we tested the hypothesis that high plasma levels of iron and calcium could increase baseline or radiation-induced DNA damage in PC patients relative to healthy controls. The present study was performed on 106 PC patients and 132 age-matched healthy individuals. CBMN assay was performed to measure mi-cronuclei (MN), nucleoplasmic bridges (NPBs), and nuclear buds (NBuds) in lymphocytes. Plasma concentrations of iron and calcium were measured using inductively coupled plasma atomic emission spectroscopy. MN, NPBs, and NBuds induced by radiation ex vivo were significantly higher in PC patients with high plasma iron (P = .004, P = .047, and P = .0003, respectively) compared to healthy controls. Radiation-induced MN and NBuds frequency were also significantly higher in PC patients (P = .001 and P = .0001, respectively) with high plasma calcium levels relative to controls. Furthermore, radiation-induced frequency of NBuds was significantly higher in PC patients (P < .0001) with high plasma levels of both iron and calcium relative to controls. Our results support the hypothesis that high iron and calcium levels in plasma increases the sensitivity to radiation-induced DNA damage and point to the need of developing nutrition-based strategies to minimize DNA damage in normal tissue of PC patients undergoing radiotherapy.</p>","PeriodicalId":18889,"journal":{"name":"Mutagenesis","volume":" ","pages":"305-314"},"PeriodicalIF":2.7,"publicationDate":"2023-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10728778/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41135604","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
MutagenesisPub Date : 2023-12-14DOI: 10.1093/mutage/gead036
Josef Horak, Dominika Vallusova, Andrea Cumova, Petr Holy, Pavel Vodicka, Alena Opattova
{"title":"Inhibition of homologous recombination repair by Mirin in ovarian cancer ameliorates carboplatin therapy response in vitro","authors":"Josef Horak, Dominika Vallusova, Andrea Cumova, Petr Holy, Pavel Vodicka, Alena Opattova","doi":"10.1093/mutage/gead036","DOIUrl":"https://doi.org/10.1093/mutage/gead036","url":null,"abstract":"Chemoresistance poses one of the most significant challenges of cancer therapy. Carboplatin (CbPt) is one of the most used chemotherapeutics in ovarian cancer (OVC) treatment. MRE11 constitutes a part of homologous recombination (HR), which is responsible for the repair of CbPt-induced DNA damage, particularly DNA crosslinks. The study’s main aim was to address the role of HR in CbPt chemoresistance in OVC and to evaluate the possibility of overcoming CbPt chemoresistance by Mirin-mediated MRE11 inhibition in an OVC cell line. Lower expression of MRE11 was associated with better overall survival in a cohort of OVC patients treated with platinum drugs (TCGA dataset, p &lt; 0.05). Using in vitro analyses, we showed that the high expression of HR genes drives the CbPt chemoresistance in our CbPt-resistant cell line model. Moreover, the HR inhibition by Mirin not only increased sensitivity to carboplatin (p &lt; 0.05) but also rescued the sensitivity in the CbPt-resistant model (p &lt; 0.05). Our results suggest that MRE11 inhibition with Mirin may represent a promising way to overcome OVC resistance. More therapy options will ultimately lead to better personalized cancer therapy and improvement of patients’ survival.","PeriodicalId":18889,"journal":{"name":"Mutagenesis","volume":"5 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2023-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138684991","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
MutagenesisPub Date : 2023-11-14DOI: 10.1093/mutage/gead024
{"title":"Abstracts of the 45th Annual Meeting of the United Kingdom Environmental Mutagen Society, 2nd – 5th July 2023 at Clontarf Castle Hotel, Dublin, Ireland","authors":"","doi":"10.1093/mutage/gead024","DOIUrl":"https://doi.org/10.1093/mutage/gead024","url":null,"abstract":"","PeriodicalId":18889,"journal":{"name":"Mutagenesis","volume":"114 15","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134957330","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
MutagenesisPub Date : 2023-10-14DOI: 10.1093/mutage/gead015
Peter Møller, Amaya Azqueta, Julen Sanz-Serrano, Tamara Bakuradze, Elke Richling, Ezgi Eyluel Bankoglu, Helga Stopper, Victoria Claudino Bastos, Sabine A S Langie, Annie Jensen, Francesca Scavone, Lisa Giovannelli, Maria Wojewódzka, Marcin Kruszewski, Vanessa Valdiglesias, Blanca Laffon, Carla Costa, Solange Costa, João Paulo Teixeira, Mirko Marino, Cristian Del Bo, Patrizia Riso, Congying Zheng, Sergey Shaposhnikov, Andrew Collins
{"title":"Visual comet scoring revisited: a guide to scoring comet assay slides and obtaining reliable results.","authors":"Peter Møller, Amaya Azqueta, Julen Sanz-Serrano, Tamara Bakuradze, Elke Richling, Ezgi Eyluel Bankoglu, Helga Stopper, Victoria Claudino Bastos, Sabine A S Langie, Annie Jensen, Francesca Scavone, Lisa Giovannelli, Maria Wojewódzka, Marcin Kruszewski, Vanessa Valdiglesias, Blanca Laffon, Carla Costa, Solange Costa, João Paulo Teixeira, Mirko Marino, Cristian Del Bo, Patrizia Riso, Congying Zheng, Sergey Shaposhnikov, Andrew Collins","doi":"10.1093/mutage/gead015","DOIUrl":"10.1093/mutage/gead015","url":null,"abstract":"<p><p>Measurement of DNA migration in the comet assay can be done by image analysis or visual scoring. The latter accounts for 20%-25% of the published comet assay results. Here we assess the intra- and inter-investigator variability in visual scoring of comets. We include three training sets of comet images, which can be used as reference for researchers who wish to use visual scoring of comets. Investigators in 11 different laboratories scored the comet images using a five-class scoring system. There is inter-investigator variation in the three training sets of comets (i.e. coefficient of variation (CV) = 9.7%, 19.8%, and 15.2% in training sets I-III, respectively). However, there is also a positive correlation of inter-investigator scoring in the three training sets (r = 0.60). Overall, 36% of the variation is attributed to inter-investigator variation and 64% stems from intra-investigator variation in scoring between comets (i.e. the comets in training sets I-III look slightly different and this gives rise to heterogeneity in scoring). Intra-investigator variation in scoring was also assessed by repeated analysis of the training sets by the same investigator. There was larger variation when the training sets were scored over a period of six months (CV = 5.9%-9.6%) as compared to 1 week (CV = 1.3%-6.1%). A subsequent study revealed a high inter-investigator variation when premade slides, prepared in a central laboratory, were stained and scored by investigators in different laboratories (CV = 105% and 18%-20% in premade slides with comets from unexposed and hydrogen peroxide-exposed cells, respectively). The results indicate that further standardization of visual scoring is desirable. Nevertheless, the analysis demonstrates that visual scoring is a reliable way of analysing DNA migration in comets.</p>","PeriodicalId":18889,"journal":{"name":"Mutagenesis","volume":" ","pages":"253-263"},"PeriodicalIF":2.7,"publicationDate":"2023-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9876699","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
MutagenesisPub Date : 2023-10-14DOI: 10.1093/mutage/gead020
Peter Møller, Amaya Azqueta, Adriana Rodriguez-Garraus, Tamara Bakuradze, Elke Richling, Ezgi Eyluel Bankoglu, Helga Stopper, Victoria Claudino Bastos, Sabine A S Langie, Annie Jensen, Sara Ristori, Francesca Scavone, Lisa Giovannelli, Maria Wojewódzka, Marcin Kruszewski, Vanessa Valdiglesias, Blanca Laffon, Carla Costa, Solange Costa, João Paulo Teixeira, Mirko Marino, Cristian Del Bo', Patrizia Riso, Congying Zheng, Sergey Shaposhnikov, Andrew Collins
{"title":"Long-term cryopreservation of potassium bromate positive assay controls for measurement of oxidatively damaged DNA by the Fpg-modified comet assay: results from the hCOMET ring trial.","authors":"Peter Møller, Amaya Azqueta, Adriana Rodriguez-Garraus, Tamara Bakuradze, Elke Richling, Ezgi Eyluel Bankoglu, Helga Stopper, Victoria Claudino Bastos, Sabine A S Langie, Annie Jensen, Sara Ristori, Francesca Scavone, Lisa Giovannelli, Maria Wojewódzka, Marcin Kruszewski, Vanessa Valdiglesias, Blanca Laffon, Carla Costa, Solange Costa, João Paulo Teixeira, Mirko Marino, Cristian Del Bo', Patrizia Riso, Congying Zheng, Sergey Shaposhnikov, Andrew Collins","doi":"10.1093/mutage/gead020","DOIUrl":"10.1093/mutage/gead020","url":null,"abstract":"<p><p>The formamidopyrimidine DNA glycosylase (Fpg)-modified comet assay is widely used for the measurement of oxidatively generated damage to DNA. However, there has not been a recommended long-term positive control for this version of the comet assay. We have investigated potassium bromate as a positive control for the Fpg-modified comet assay because it generates many Fpg-sensitive sites with a little concurrent generation of DNA strand breaks. Eight laboratories used the same procedure for the treatment of monocytic THP-1 cells with potassium bromate (0, 0.5, 1.5, and 4.5 mM) and subsequent cryopreservation in a freezing medium consisting of 50% foetal bovine serum, 40% RPMI-1640 medium, and 10% dimethyl sulphoxide. The samples were analysed by the Fpg-modified comet assay three times over a 3-year period. All laboratories obtained a positive concentration-response relationship in cryopreserved samples (linear regression coefficients ranging from 0.79 to 0.99). However, there was a wide difference in the levels of Fpg-sensitive sites between the laboratory with the lowest (4.2% Tail DNA) and highest (74% Tail DNA) values in THP-1 cells after exposure to 4.5 mM KBrO3. In an attempt to assess sources of inter-laboratory variation in Fpg-sensitive sites, comet images from one experiment in each laboratory were forwarded to a central laboratory for visual scoring. There was high consistency between measurements of %Tail DNA values in each laboratory and the visual score of the same comets done in the central laboratory (r = 0.98, P < 0.001, linear regression). In conclusion, the results show that potassium bromate is a suitable positive comet assay control.</p>","PeriodicalId":18889,"journal":{"name":"Mutagenesis","volume":" ","pages":"264-272"},"PeriodicalIF":2.7,"publicationDate":"2023-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10042290","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
MutagenesisPub Date : 2023-10-14DOI: 10.1093/mutage/gead014
Peter Møller, Amaya Azqueta, Miguel Collia, Tamara Bakuradze, Elke Richling, Ezgi Eyluel Bankoglu, Helga Stopper, Victoria Claudino Bastos, Sabine A S Langie, Annie Jensen, Sara Ristori, Francesca Scavone, Lisa Giovannelli, Maria Wojewódzka, Marcin Kruszewski, Vanessa Valdiglesias, Blanca Laffon, Carla Costa, Solange Costa, João Paulo Teixeira, Mirko Marino, Cristian Del Bo, Patrizia Riso, Congying Zheng, Sergey Shaposhnikov, Andrew Collins
{"title":"Inter-laboratory variation in measurement of DNA damage by the alkaline comet assay in the hCOMET ring trial.","authors":"Peter Møller, Amaya Azqueta, Miguel Collia, Tamara Bakuradze, Elke Richling, Ezgi Eyluel Bankoglu, Helga Stopper, Victoria Claudino Bastos, Sabine A S Langie, Annie Jensen, Sara Ristori, Francesca Scavone, Lisa Giovannelli, Maria Wojewódzka, Marcin Kruszewski, Vanessa Valdiglesias, Blanca Laffon, Carla Costa, Solange Costa, João Paulo Teixeira, Mirko Marino, Cristian Del Bo, Patrizia Riso, Congying Zheng, Sergey Shaposhnikov, Andrew Collins","doi":"10.1093/mutage/gead014","DOIUrl":"10.1093/mutage/gead014","url":null,"abstract":"<p><p>The comet assay is a simple and versatile method for measurement of DNA damage in eukaryotic cells. More specifically, the assay detects DNA migration from agarose gel-embedded nucleoids, which depends on assay conditions and the level of DNA damage. Certain steps in the comet assay procedure have substantial impact on the magnitude of DNA migration (e.g. electric potential and time of electrophoresis). Inter-laboratory variation in DNA migration levels occurs because there is no agreement on optimal assay conditions or suitable assay controls. The purpose of the hCOMET ring trial was to test potassium bromate (KBrO3) as a positive control for the formamidopyrimidine DNA glycosylase (Fpg)-modified comet assay. To this end, participating laboratories used semi-standardized protocols for cell culture (i.e. cell culture, KBrO3 exposure, and cryopreservation of cells) and comet assay procedures, whereas the data acquisition was not standardized (i.e. staining of comets and image analysis). Segregation of the total variation into partial standard deviation (SD) in % Tail DNA units indicates the importance of cell culture procedures (SD = 10.9), comet assay procedures (SD = 12.3), staining (SD = 7.9) and image analysis (SD = 0.5) on the overall inter-laboratory variation of DNA migration (SD = 18.2). Future studies should assess sources of variation in each of these steps. On the positive side, the hCOMET ring trial demonstrates that KBrO3 is a robust positive control for the Fpg-modified comet assay. In conclusion, the hCOMET ring trial has demonstrated a high reproducibility of detecting genotoxic effects by the comet assay, but inter-laboratory variation of DNA migration levels is a concern.</p>","PeriodicalId":18889,"journal":{"name":"Mutagenesis","volume":" ","pages":"283-294"},"PeriodicalIF":2.7,"publicationDate":"2023-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9876152","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
MutagenesisPub Date : 2023-10-14DOI: 10.1093/mutage/gead019
Peter Møller, Amaya Azqueta, Adriana Rodriguez-Garraus, Tamara Bakuradze, Elke Richling, Ezgi Eyluel Bankoglu, Helga Stopper, Victoria Claudino Bastos, Sabine A S Langie, Annie Jensen, Sara Ristori, Francesca Scavone, Lisa Giovannelli, Maria Wojewódzka, Marcin Kruszewski, Vanessa Valdiglesias, Blanca Laffon, Carla Costa, Solange Costa, João Paulo Teixeira, Mirko Marino, Cristian Del Bo', Patrizia Riso, Congying Zhang, Sergey Shaposhnikov, Andrew Collins
{"title":"DNA strand break levels in cryopreserved mononuclear blood cell lines measured by the alkaline comet assay: results from the hCOMET ring trial.","authors":"Peter Møller, Amaya Azqueta, Adriana Rodriguez-Garraus, Tamara Bakuradze, Elke Richling, Ezgi Eyluel Bankoglu, Helga Stopper, Victoria Claudino Bastos, Sabine A S Langie, Annie Jensen, Sara Ristori, Francesca Scavone, Lisa Giovannelli, Maria Wojewódzka, Marcin Kruszewski, Vanessa Valdiglesias, Blanca Laffon, Carla Costa, Solange Costa, João Paulo Teixeira, Mirko Marino, Cristian Del Bo', Patrizia Riso, Congying Zhang, Sergey Shaposhnikov, Andrew Collins","doi":"10.1093/mutage/gead019","DOIUrl":"10.1093/mutage/gead019","url":null,"abstract":"<p><p>The comet assay is widely used in biomonitoring studies for the analysis of DNA damage in leukocytes and peripheral blood mononuclear cells. Rather than processing blood samples directly, it can be desirable to cryopreserve whole blood or isolated cells for later analysis by the comet assay. However, this creates concern about artificial accumulation of DNA damage during cryopreservation. In this study, 10 laboratories used standardized cryopreservation and thawing procedures of monocytic (THP-1) or lymphocytic (TK6) cells. Samples were cryopreserved in small aliquots in 50% foetal bovine serum, 40% cell culture medium, and 10% dimethyl sulphoxide. Subsequently, cryopreserved samples were analysed by the standard comet assay on three occasions over a 3-year period. Levels of DNA strand breaks in THP-1 cells were increased (four laboratories), unaltered (four laboratories), or decreased (two laboratories) by long-term storage. Pooled analysis indicates only a modest positive association between storage time and levels of DNA strand breaks in THP-1 cells (0.37% Tail DNA per year, 95% confidence interval: -0.05, 0.78). In contrast, DNA strand break levels were not increased by cryopreservation in TK6 cells. There was inter-laboratory variation in levels of DNA strand breaks in THP-1 cells (SD = 3.7% Tail DNA) and TK6 reference sample cells (SD = 9.4% Tail DNA), whereas the intra-laboratory residual variation was substantially smaller (i.e. SD = 0.4%-2.2% Tail DNA in laboratories with the smallest and largest variation). In conclusion, the study shows that accumulation of DNA strand breaks in cryopreserved mononuclear blood cell lines is not a matter of concern.</p>","PeriodicalId":18889,"journal":{"name":"Mutagenesis","volume":" ","pages":"273-282"},"PeriodicalIF":2.7,"publicationDate":"2023-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10060071","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
MutagenesisPub Date : 2023-10-14DOI: 10.1093/mutage/gead026
David Kirkland, George Douglas
{"title":"Obituary to John Ashby (19 April 1943-03 October 2022).","authors":"David Kirkland, George Douglas","doi":"10.1093/mutage/gead026","DOIUrl":"10.1093/mutage/gead026","url":null,"abstract":"","PeriodicalId":18889,"journal":{"name":"Mutagenesis","volume":" ","pages":"251-252"},"PeriodicalIF":2.7,"publicationDate":"2023-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10388184","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}