Radiosensitivity in breast cancer assessed by the Comet and micronucleus assays

Djuzenova, Cholpon S.; Mühl, Bettina; Fehn, Martin; Oppitz, Ulrich; Müller, Berit; Flentje, Michael

doi:10.1038/sj.bjc.6603005

Cited by 41 publications

(31 citation statements)

References 48 publications

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“…15,[27][28][29] In contrast, other researchers have not found significant differences between the basal damage in lymphocytes from patients with sporadic breast carcinoma and healthy donors. [30][31][32][33] In the present study, the comet assay results of samples from healthy donors and pre-treatment cancer patients were not significantly different, either.…”

Section: A U T H O R P R O O Fcontrasting

confidence: 58%

Relationship between Genotoxic Effects of Breast Cancer Treatments and Patient Basal DNA Integrity

Ceballos

Funes

Massa

et al. 2014

J Environ Pathol Toxicol Oncol

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Radiotherapy and chemotherapy cause genotoxic side effects that are highly variable among patients. In this study, we evaluated DNA integrity using the comet assay in peripheral blood lymphocytes from breast cancer patients before ("pre-treatment patients"; n = 47) and after ("post-treatment patients"; n = 24) radiotherapy and/or chemotherapy treatment and from healthy donors (n = 15). Comet evaluation was made by visual (types 0-4) and digital (percentage of DNA remaining in the comet head = % head DNA) analysis. The association between the level of DNA damage and cancer prognostic factors was assessed. The treatments caused a significant increase in DNA damage registered by both visual (p < 0.001) and digital (p < 0.001) analyses. No significant associations between the level of DNA damage in pre-treatment patients and cancer prognostic factors were found. A significant correlation between the comet results from each patient before and after treatment (r = 0.64, p = 0.001) was observed. The % head DNA in post-treatment samples from patients with a high level of DNA damage before treatment (30.3 ± 3.1%, p < 0.01) was lower than in post-treatment samples from patients with a low-to-medium level of DNA damage before therapy (49.2 ± 4.4%). These results support the usefulness of the comet assay as a sensitive technique to evaluate basal DNA status and DNA damage caused by cancer treatments. The comet assay could contribute to treatment decisions, especially by taking into account the patient's basal DNA damage before therapy.

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Section: A U T H O R P R O O Fcontrasting

confidence: 58%

Relationship between Genotoxic Effects of Breast Cancer Treatments and Patient Basal DNA Integrity

Ceballos

Funes

Massa

et al. 2014

J Environ Pathol Toxicol Oncol

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“…Comet assay was performed under alkaline conditions following the protocol reported elsewhere (Djuzenova et al, 2006). Just before irradiation, drug-treated and control cells were embedded in a thin layer of agarose spread on glass microscope slides.…”

Section: Comet Assaymentioning

confidence: 99%

Novel HSP90 inhibitors, NVP-AUY922 and NVP-BEP800, radiosensitise tumour cells through cell-cycle impairment, increased DNA damage and repair protraction

et al. 2010

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BACKGROUND: Heat-shock protein 90 (Hsp90) has a crucial role in both the stabilisation and regulation of various proteins, including those related to radioresistance. Inhibition of Hsp90 may therefore provide a strategy for enhancing the radiosensitivity of tumour cells. This study explores the responses of four tumour cell lines (A549, GaMG, HT 1080 and SNB19) to combined treatment with ionising radiation (IR) and two novel inhibitors of Hsp90, NVP-AUY922 and NVP-BEP800. The techniques used included cell and colony counts, expression of Hsp90, Hsp70, Akt, survivin, cleaved caspase 3, p53, cell-cycle progression and associated proteins. DNA damage was analysed by histone gH2AX and Comet assays. RESULTS: We found that NVP-AUY922 and NVP-BEP800 enhanced radiosensitivity in all tested cell lines. In contrast, only two cell lines (HT 1080 and GaMG) exhibited an increased rate of apoptosis after drug pretreatment, as revealed by western blot. In all tested cell lines, the expression of histone gH2AX, a marker of DNA double-strand breaks, after combined drug-IR treatment was higher and its decay rate was slower than those after each single treatment modality. Drug-IR treatment also resulted in impaired cell-cycle progression, as indicated by S-phase depletion and G2/M arrest. In addition, the cell cycle-associated proteins, Cdk1 and Cdk4, were downregulated after Hsp90 inhibition. INTERPRETATION: These findings show that the novel inhibitors of Hsp90 can radiosensitise tumour cell lines of different entities through destabilisation and depletion of several Hsp90 client proteins, thus causing the depletion of S phase and G2/M arrest, increased DNA damage and repair protraction and, to some extent, apoptosis. The results might have important implications for the radiotherapy of solid tumours.

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“…The Comet assay was performed under alkaline conditions following a protocol reported elsewhere (21,22). DNA fragmentation was quantified from the 'Tail Moment' (TM, given in arbitrary units, a.u.…”

Section: Cellsmentioning

confidence: 99%

Intracellular delivery of 2-deoxy-D-glucose into tumor cells by long-term cultivation and through swelling-activated pathways: implications for radiation treatment

Djuzenova¹

2009

Mol Med Rep

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Abstract. 2-Deoxy-D-glucose (2DG), a well-known inhibitor of anaerobic glycolysis, is expected to exert cytotoxic and radiosensitizing effects. In order to test this hypothesis, the response of four tumor cell lines (U87-MG, GaMG, A549 and HT1080) to 2DG was analyzed for cell proliferation, changes in cell volume and nucleus size, as well as for radiation-induced DNA fragmentation, measured by the alkaline Comet assay. Two methods were used for loading cells with 2DG. The long-term method included cell cultivation in the presence of 5 mM 2DG for 24 h, while rapid intracellular delivery of 2DG was achieved by exposing the cells for 20 min to a hypotonic solution containing 100 mM 2DG. Irrespective of the loading method, 2DG inhibited the growth of HT1080 and A549 cells. In contrast, two glioblastoma lines (U87 and GaMG) were resistant to 2DG. In three of the four cell lines (all except HT1080), long-term treatment with 2DG reduced radiation-induced DNA fragmentation in conjunction with 2DG-mediated nucleus shrinkage (probably via chromatin condensation) in non-irradiated cells. Complementary volumetric experiments revealed the avid hypotonic uptake of 2DG by all tumor lines. Nonetheless, only HT1080 cells exhibited a significant increase in radiation-induced DNA fragmentation upon hypotonic loading with 2DG, associated with marked nucleus expansion in non-irradiated samples. Our data suggest that, dependant on cell type as well as on medium composition and tonicity, sugar treatment can induce the compaction or expansion of chromatin, thus decreasing or increasing radiation-induced DNA fragmentation. These results raise interesting questions for further studies on the mechanistic links between the sugar-modulated cell volume changes, chromatin structure and radiosensitivity of tumor and normal cells.

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Radiosensitivity in breast cancer assessed by the Comet and micronucleus assays

Cited by 41 publications

References 48 publications

Relationship between Genotoxic Effects of Breast Cancer Treatments and Patient Basal DNA Integrity

Relationship between Genotoxic Effects of Breast Cancer Treatments and Patient Basal DNA Integrity

Novel HSP90 inhibitors, NVP-AUY922 and NVP-BEP800, radiosensitise tumour cells through cell-cycle impairment, increased DNA damage and repair protraction

Intracellular delivery of 2-deoxy-D-glucose into tumor cells by long-term cultivation and through swelling-activated pathways: implications for radiation treatment

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