Response to X-Irradiation of Fanconi Anemia Homozygous and Heterozygous Cells Assessed by the Single-Cell Gel Electrophoresis (Comet) Assay

Djuzenova, Cholpon S.; Rothfuß, Andreas; Oppitz, Ulrich; Speit, Günter; Schindler, Detlev; Hoehn, Holger; Flentje, Michael

doi:10.1038/labinvest.3780226

Cited by 43 publications

(29 citation statements)

References 36 publications

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“…The mean index of DEB-induced chromosome breakage was higher in obligate FA heterozygotes relative to controls (0.1370.06 versus 0.0770.09), although there was overlap between these groups . Also, comet assays of FA heterozygotes showed an increased release of fragmented DNA after exposure to X-irradiation compared to controls (Djuzenova et al, 2001). However, Swift's original findings of an increased cancer risk in FA relatives were not confirmed in a later and larger study of relatives in 25 FA families (Swift et al, 1980).…”

Section: Epidemiologymentioning

confidence: 86%

Fanconi anaemia genes and susceptibility to cancer

2006

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Fanconi anaemia (FA) is a rare recessive disorder associated with chromosomal fragility, aplastic anaemia, congenital abnormalities and a high risk of cancer, including acute myeloid leukaemia and squamous cell carcinomas. The identification of 11 different FA genes has revealed a complex web of interacting proteins that are involved in the recognition or repair of DNA interstrand crosslinks and perhaps other forms of DNA damage. Bi-allelic mutations in BRCA2 are associated with a rare and highly cancer-prone form of FA, and the DNA helicase BRIP1 (formerly BACH1) is mutated in FA group J. There is little convincing evidence that FA heterozygotes are at increased risk of cancer, but larger studies are needed to address the possibility of modest risk effects. Somatic inactivation of the FA pathway by mutation or epigenetic silencing has been observed in several different types of sporadic cancer, and this may have important implications for targeted chemotherapy. Inhibition of this pathway represents a possible route to sensitization of tumours to DNA crosslinking drugs such as cisplatin.

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Section: Epidemiologymentioning

confidence: 86%

Fanconi anaemia genes and susceptibility to cancer

2006

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“…If the mutations identified in this study are indeed germ line, then heterozygous FANCA deletions may be considered to be low penetrance alleles for conferring AML risk. Evidence for a heterozygote effect has been provided by Djuzenova et al, 41 who used an alkaline single-cell gel electrophoresis (comet) assay to show that cells from FA heterozygotes that were exposed to X-rays had higher initial DNA damage rates and a prolonged DNA repair half-time compared to control cells. Also, Pearson et al 42 found that FA heterozygotes had higher mean rates of chromosomal aberrations following exposure to diepoxybutane than normal controls.…”

Section: Discussionmentioning

confidence: 99%

Deletion and reduced expression of the Fanconi anemia FANCA gene in sporadic acute myeloid leukemia

et al. 2004

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Fanconi anemia (FA) is an autosomal recessive chromosomal instability disorder caused by mutations in one of seven known genes (FANCA,C,D2,E,F,G and BRCA2). Mutations in the FANCA gene are the most prevalent, accounting for two-thirds of FA cases. Affected individuals have greatly increased risks of acute myeloid leukemia (AML). This raises the question as to whether inherited or acquired mutations in FA genes might be involved in the development of sporadic AML. Quantitative fluorescent PCR was used to screen archival DNA from sporadic AML cases for FANCA deletions, which account for 40% of FANCA mutations in FA homozygotes. Four heterozygous deletions were found in 101 samples screened, which is 35-fold higher than the expected population frequency for germline FANCA deletions (Po0.0001). Sequencing FANCA in the AML samples with FANCA deletions did not detect mutations in the second allele and there was no evidence of epigenetic silencing by hypermethylation. However, real-time quantitative PCR analysis in these samples showed reduced expression of FANCA compared to nondeleted AML samples and to controls. These findings suggest that gene deletions and reduced expression of FANCA may be involved in the promotion of genetic instability in a subset of cases of sporadic AML.

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“…The Comet assay was performed under alkaline conditions following a modified protocol initially reported elsewhere (Singh et al, 1988;Djuzenova et al, 1999Djuzenova et al, , 2001. Fully frosted microscope slides (SuperFrost Plus s Menzel GmbH, Braunschweig, Germany) were dipped up to one-fourth the frosted area in a hot 0.9% normal-melting-point agarose (Roth, 2268.2; Karlsruhe, Germany) in PBS.…”

Section: Alkaline Comet Assay (Slide Method)mentioning

confidence: 99%

“…We have shown recently that this method allows the discrimination of carriers of chromosome instability syndromes including ataxia telangiectasia and Fanconi anaemia (Djuzenova et al, 1999(Djuzenova et al, , 2001). In addition, using the Comet assay, we have found the background and induced DNA damage in the peripheral blood lymphocytes from BC patients to be similar to that in control individuals (Djuzenova et al, 1999).…”

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confidence: 99%

Radiosensitivity in breast cancer assessed by the Comet and micronucleus assays

et al. 2006

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Spontaneous and radiation-induced genetic instability of peripheral blood mononuclear cells derived from unselected breast cancer (BC) patients (n ¼ 50) was examined using the single-cell gel electrophoresis (Comet) assay and a modified G2 micronucleus (MN) test. Cells from apparently healthy donors (n ¼ 16) and from cancer patients (n ¼ 9) with an adverse early skin reaction to radiotherapy (RT) served as references. Nonirradiated cells from the three tested groups exhibited similar baseline levels of DNA fragmentation assessed by the Comet assay. Likewise, the Comet analysis of in vitro irradiated (5 Gy) cells did not reveal any significant differences among the three groups with respect to the initial and residual DNA fragmentation, as well as the DNA repair kinetics. The G2 MN test showed that cells from cancer patients with an adverse skin reaction to RT displayed increased frequencies of both spontaneous and radiation-induced MN compared to healthy control or the group of unselected BC patients. Two patients from the latter group developed an increased early skin reaction to RT, which was associated with an increased initial DNA fragmentation in vitro only in one of them. Cells from the other BC patient exhibited a striking slope in the dose -response curve detected by the G2 MN test. We also found that previous RT strongly increased both spontaneous and in vitro radiation-induced MN levels, and to a lesser extent, the radiation-induced DNA damage assessed by the Comet assay. These data suggest that clinical radiation may provoke genetic instability and/or induce persistent DNA damage in normal cells of cancer patients, thus leading to increased levels of MN induction and DNA fragmentation after irradiation in vitro. Therefore, care has to be taken when blood samples collected postradiotherapeutically are used to assess the radiosensitivity of cancer patients.

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Response to X-Irradiation of Fanconi Anemia Homozygous and Heterozygous Cells Assessed by the Single-Cell Gel Electrophoresis (Comet) Assay

Cited by 43 publications

References 36 publications

Fanconi anaemia genes and susceptibility to cancer

Fanconi anaemia genes and susceptibility to cancer

Deletion and reduced expression of the Fanconi anemia FANCA gene in sporadic acute myeloid leukemia

Radiosensitivity in breast cancer assessed by the Comet and micronucleus assays

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