Long-term biomonitoring of breast cancer patients under adjuvant chemotherapy: the comet assay as a possible predictive factor

Uriol, E.; Sierra, Marta; Comendador, Miguel A.; Fra, J.; Martínez–Camblor, Pablo; Lacave, A.J.; Sierra, María R.

doi:10.1093/mutage/ges050

Cited by 16 publications

(14 citation statements)

References 65 publications

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“…Guerreiro et al [ 65 ] report an increased frequency of MN and binucleate in breast cancer cells exposed to DOX. These data corroborate with Uriol et al [ 66 ] who report that most chemotherapeutic treatments induce different DNA damage as observed in this study.…”

Section: Discussionsupporting

confidence: 94%

Persistent Increased Frequency of Genomic Instability in Women Diagnosed with Breast Cancer: Before, during, and after Treatments

Paz

Sobral²,

Picada

et al. 2018

Oxidative Medicine and Cellular Longevity

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This study aimed to evaluate DNA damage in patients with breast cancer before treatment (background) and after chemotherapy (QT) and radiotherapy (RT) treatment using the Comet assay in peripheral blood and the micronucleus test in buccal cells. We also evaluated repair of DNA damage after the end of RT, as well as the response of patient's cells before treatment with an oxidizing agent (H2O2; challenge assay). Fifty women with a mammographic diagnosis negative for cancer (control group) and 100 women with a diagnosis of breast cancer (followed up during the treatment) were involved in this study. The significant DNA damage was observed by increasing in the index and frequency of damage along with the increasing of the frequency of micronuclei in peripheral blood and cells of the buccal mucosa, respectively. Despite the variability of the responses of breast cancer patients, the individuals presented lesions on the DNA, detected by the Comet assay and micronucleus Test, from the diagnosis until the end of the oncological treatment and were more susceptible to oxidative stress. We can conclude that the damages were due to clastogenic and/or aneugenic effects related to the neoplasia itself and that they increased, especially after RT.

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Section: Discussionsupporting

confidence: 94%

Persistent Increased Frequency of Genomic Instability in Women Diagnosed with Breast Cancer: Before, during, and after Treatments

Paz

Sobral²,

Picada

et al. 2018

Oxidative Medicine and Cellular Longevity

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“…This result supported the potential of the Comet assay in the analysis of the chemotherapy response. 53 …”

Section: Discussionmentioning

confidence: 99%

Cisplatin resistance in cell models: evaluation of metallomic and biological predictive biomarkers to address early therapy failure

et al. 2017

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Cisplatin, one of the most extensively used metallodrugs in cancer treatment, presents the important drawback of patient resistance. This resistance is the consequence of different processes including those preventing the formation of DNA adducts and/or their quick removal. Thus, a tool for the accurate detection and quantitation of cisplatin-induced adducts might be valuable for predicting patient resistance. To prove the validity of such an assumption, highly sensitive plasma mass spectrometry (ICP-MS) strategies were applied to determine DNA adduct levels and intracellular Pt concentrations. These two metal-relative parameters were combined with an evaluation of biological responses in terms of genomic stability (with the Comet assay) and cell cycle progression (by flow cytometry) in four human cell lines of different origins and cisplatin sensitivities (A549, GM04312, A2780 and A2780cis), treated with low cisplatin doses (5, 10 and 20 mM for 3 hours). Cell viability and apoptosis were determined as resistance indicators. Univariate linear regression analyses indicated that quantitation of cisplatin-induced G-G intra-strand adducts, measured 1 h after treatment, was the best predictor for viability and apoptosis in all of the cell lines. Multivariate linear regression analyses revealed that the prediction improved when the intracellular Pt content or the Comet data were included in the analysis, for all sensitive cell lines and for the A2780 and A2780cis cell lines, respectively. Thus, a reliable cisplatin resistance predictive model, which combines the quantitation of adducts by HPLC-ICP-MS, and their repair, with the intracellular Pt content and induced genomic instability, might be essential to identify early therapy failure. Significance to metallomicsKnowledge about cisplatin as a chemotherapy drug is extensive, including information about the several processes that contribute to its resistance, the main problem of using this chemical. However, this knowledge and information does not yet allow the early identification of resistant tumors/patients, one of the most desired aims of clinicians. In this work we have developed a model that might allow the early detection of chemical resistance and, more importantly, might do so mostly regardless of the resistance mechanism involved, because it determines the dynamics of adduct induction/repair, considering chemical influx/efflux and induced genomic instability.

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“…In some cases, results obtained after treatment are compared with the ones attained before treatment [ 17 ]. This same type of result analysis has also been carried out in studies looking at genetic effects after chemotherapy in cancer patients [ 18 ]. Observational studies using comet assay often comprise case-control and crosssectional study designs.…”

Section: Comet Assay For Human Biomonitoringmentioning

confidence: 99%

The Comet Assay In Vivo in Humans

Costa

Teixeira

2014

Genotoxicity and DNA Repair

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In the last decades, the comet assay has been used as a molecular biomarker to detect DNA damage in several human biomonitoring studies. Nevertheless, many of these studies are often inconclusive or offer poor quality data due to study design constraints. This chapter describes not only the experimental protocol to carry the alkaline version of the comet assay in human cells but also considers many of the obstacles that the researcher faces while carrying a human biomonitoring study, such as sample size, sample type, sample collection, statistics, and result communication. Understanding assay limitations, both experimental and biological, is essential to improve both data quality and data relevance obtained and to guarantee that comet assay continues to provide enhanced reliability as a biomarker in human biomonitoring studies.Key words Comet assay , Human biomonitoring , Exposure , Lymphocytes , Whole blood Comet Assay for Human BiomonitoringComet assay (also designated of single cell gel electrophoresis) is a rapid, simple, visual, and sensitive method to detect DNA breakage in eukaryotic cells [ 1 ].Briefl y, cells are embedded in agarose on a microscope slide, lysed with detergent to remove cell and nuclear membranes, and treated with a high salt solution. Nucleoids are formed, containing non-nucleosomal but still supercoiled DNA. Any breaks present in the DNA cause the supercoiling to relax locally and loops of DNA are then free to extend toward the anode during electrophoresis. At the end of this procedure, damaged cells will resemble comets (hence the name comet assay ) while non-damaged cells maintain their round appearance. Comets are viewed by fl uorescence microscopy after staining with a suitable fl uorescent DNA-binding dye [ 2 ].The pH of unwinding solution is responsible for differences in method sensitivity, as the conversion of alkali-labile sites to strand breaks is a process dependent on the pH and time of alkaline treatment. Under alkaline (pH > 13) conditions, the assay potentially

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Long-term biomonitoring of breast cancer patients under adjuvant chemotherapy: the comet assay as a possible predictive factor

Cited by 16 publications

References 65 publications

Persistent Increased Frequency of Genomic Instability in Women Diagnosed with Breast Cancer: Before, during, and after Treatments

Persistent Increased Frequency of Genomic Instability in Women Diagnosed with Breast Cancer: Before, during, and after Treatments

Cisplatin resistance in cell models: evaluation of metallomic and biological predictive biomarkers to address early therapy failure

The Comet Assay In Vivo in Humans

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