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Chang JL, Chen G, Lampe JW, Ulrich CM. DNA damage and repair measurements from cryopreserved lymphocytes without cell culture--a reproducible assay for intervention studies. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2006; 47:503-8. [PMID: 16673412 DOI: 10.1002/em.20219] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Single-cell gel electrophoresis (the Comet assay) can be used to measure DNA damage and DNA repair capacity (DRC). However, to test DRC of cryopreserved lymphocytes, published methods include steps for cell culturing and phytohemagglutinin stimulation, which may limit use of this assay in intervention studies. We developed a modified Comet assay protocol that allows us to measure DRC from cryopreserved lymphocytes without these in vitro manipulations. Assay reproducibility was evaluated by performing the assay six times on different dates using six aliquots from one blood draw of one individual. The interindividual variation was assessed by performing the assay using one aliquot from six individuals. When gamma-irradiation was used as the mutagen, intra-assay coefficients of variation (CVs.) for baseline DNA damage, damage after gamma-irradiation exposure, and DRC--measured as tail moment--were 8, 31, and 10%, respectively. Interindividual CVs. were higher. When H(2)O(2) was used as the mutagen, intra-assay CVs. for damage measurements were lower for a protocol modification that included damage and repair at 37 degrees C (CVs. ranging from 8 to 35%) than for the more standard 4 degrees C protocol. Analyzing moment arm--the average distance of DNA migration within the tail--yielded similar results. DNA repair was successfully detected in each experiment. Comparing freshly isolated lymphocytes to cryopreserved lymphocytes from the same individuals' blood draw indicated that DRC was highly correlated when determined using moment arm values. This modified protocol extends the use of the Comet assay to measuring DRC in intervention studies (e.g., dietary interventions) in that it assesses cellular response after cryopreservation without cell culture or other extensive manipulation.
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Affiliation(s)
- Jyh-Lurn Chang
- Fred Hutchinson Cancer Research Center, Seattle, Washington 98109-1024, USA
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52
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Abstract
Research of the role of oxidative DNA damage is well established in experimental carcinogenesis. A large number of human studies on biomarkers of oxidative DNA damage, in particular related to guanine oxidation, have been published. The level of oxidative DNA damage and repair activity can be quite different between tumor and normal tissues; case-control studies have shown increased levels of oxidative DNA damage and decreased repair capacity in leukocytes from cases. Similarly, the urinary biomarkers of oxidative DNA damage may be elevated in patients with cancer. However, such studies are likely to be associated with reverse causality. Case-control studies of genetic polymorphisms in DNA repair enzymes suggest that the common variant Ser326Cys in OGG1 may be a risk factor for lung cancer, whereas a rare variant in OGG1 and germ line mutations in the corresponding mismatch repair gene MYH are risk factors for hereditary colon cancer. Cohort studies are required to provide evidence that a high level of oxidative DNA damage implies a high risk of cancer. However, this represents a real challenge considering the large number of subjects and long followup time required with likely spurious oxidation of DNA during collection, assay and/or storage of samples.
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Affiliation(s)
- Steffen Loft
- Institute of Public Health, University of Copenhagen, Copenhagen K, Denmark.
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Iwakawa M, Goto M, Noda S, Sagara M, Yamada S, Yamamoto N, Kawakami Y, Matsui Y, Miyazawa Y, Yamazaki H, Tsuji H, Ohno T, Mizoe J, Tsujii H, Imai T. DNA repair capacity measured by high throughput alkaline comet assays in EBV-transformed cell lines and peripheral blood cells from cancer patients and healthy volunteers. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2005; 588:1-6. [PMID: 16260175 DOI: 10.1016/j.mrgentox.2005.07.012] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2005] [Revised: 06/21/2005] [Accepted: 07/12/2005] [Indexed: 11/26/2022]
Abstract
We collected peripheral blood (PB) from 556 patients with various types of cancer who had undergone radiotherapy and from 81 healthy volunteers. We exposed whole PB and Epstein-Barr virus-transformed lymphoblastoid cell lines (EBLs) derived from the PB mononucleocytes to X-irradiation (5 Gy). Using the alkaline comet assay, we measured the immediate DNA damage and, at 15 min, the % residual damage. In PB, the immediate damage was similar in patients and healthy volunteers while the % residual damage (mean+/-S.D.) was significantly higher in patients with breast (54.3+/-A23.9), cervical (54.7+/-A23.9), head/neck (56.8+/-A24.4), lung (60.1+/-23.5), or esophageal cancers (59.5+/-A33.7) than in healthy donors (42.9+/-19.6) (P<0.05). We did not observe such differences in the EBV-transformed cell lines. Thus, radiation sensitivity of fresh PB cells measured by the alkaline comet assay was related to cancer status.
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Affiliation(s)
- Mayumi Iwakawa
- RadGenomics Project, Frontier Research Center, National Institute of Radiological Sciences, 4-9-1, Anagawa, Inage-ku, Chiba 263-8555, Japan
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Hoffmann H, Högel J, Speit G. The effect of smoking on DNA effects in the comet assay: a meta-analysis. Mutagenesis 2005; 20:455-66. [PMID: 16280345 DOI: 10.1093/mutage/gei064] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The comet assay (alkaline single-cell gel electrophoresis, SCG or SCGE) is frequently used in biomonitoring to detect genotoxic effects in humans exposed at the workplace or in their environment. Because of its ready accessibility, blood is most frequently used in such studies. Many studies investigated cigarette smoking either as a genotoxic exposure itself or as a potential confounding factor in occupational studies. However, although smoking is considered to be a relevant exposure towards various genotoxins, conflicting results have been reported in the comet assay studies. The actual reasons for this discrepancy are not known. To further evaluate evidence for smoking-related DNA effects in the comet assay, we now used a meta-analysis approach based on a literature search. We identified 38 studies from 37 publications which were suited for a formal meta-analysis based on the standardized mean difference (SMD) between the study groups. The evaluation of these 38 studies indicated higher levels of DNA damage in smokers than in non-smokers [under a random effects model, SMD = 0.55, 95% confidence interval = (0.16-0.93)]. Subdividing these studies into studies investigating the effect of smoking as a genotoxic exposure (Type A studies, n = 12) and studies investigating smoking as a potential confounder in occupational studies (Type B, n = 26) indicated a significant difference only in Type A studies but not in Type B studies. Furthermore, studies using image analysis or image length measurements (n = 23) only indicated a tendency for a genotoxic effect of smoking, whereas studies using an arbitrary score (n = 15) found a significantly higher level of DNA damage in smokers.
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Abstract
DNA base excision repair (BER) is the main pathway for repair of endogenous damage in human cells. It was expected that a number of degenerative diseases could derive from BER defects. On the contrary, the link between BER defects and human pathology is elusive and the literature is full of conflicting results. The fact that most studies have investigated DNA variations but not their functional consequences has probably contributed to this confusing picture. From a functional point of view, it is likely that gross BER defects are simply not compatible with life and only limited reductions can be observed. Notwithstanding those limits, the pathological consequences of partial BER defects might be widespread and significant at the population level. This starts to emerge in particular for colorectal and lung cancer.
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Affiliation(s)
- Guido Frosina
- Department of Aetiology and Epidemiology, Mutagenesis Laboratory, Istituto Nazionale Ricerca Cancro, Largo Rosanna Benzi n. 10, 16132 Genova, Italy.
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Yeh CC, Sung FC, Tang R, Chang-Chieh CR, Hsieh LL. Polymorphisms of the XRCC1, XRCC3, & XPD genes, and colorectal cancer risk: a case-control study in Taiwan. BMC Cancer 2005; 5:12. [PMID: 15679883 PMCID: PMC549041 DOI: 10.1186/1471-2407-5-12] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2004] [Accepted: 01/28/2005] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND Recent studies relating to the association between DNA repair-gene polymorphisms and colorectal cancer risk would, to the best of our knowledge, appear to be very limited. This study was designed to examine the polymorphisms associated with three DNA repair genes, namely: XRCC1 Arg399Gln, XRCC3 Thr241Met and XPD Lys751Gln, and investigate their role as susceptibility markers for colorectal cancer. METHODS We conducted a case-control study including 727 cases of cancer and 736 hospital-based age- and sex-matched healthy controls to examine the role of genetic polymorphisms of three DNA-repair genes (XRCC1, XRCC3 and XPD) in the context of colorectal cancer risk for the Taiwanese population. Genomic DNA isolated from 10 ml whole blood was used to genotype XRCC1 Arg399Gln, XRCC3 Thr241Met and XPD Lys751Gln by means of polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analysis. RESULTS The risk for colorectal cancer did not appear to differ significantly amongst individuals featuring the XRCC1 399Arg/Arg genotype (OR = 1.18; 95% CI, 0.96-1.45), the XRCC3 241Thr/Thr genotype (OR = 1.25; 95% CI, 0.88-1.79) or the XPD 751Gln allele (OR = 1.20; 95% CI, 0.90-1.61), although individuals featuring a greater number of risk genotypes (genotype with OR greater than 1) did experience a higher risk for colorectal cancer when compared to those who didn't feature any risk genotypes (Trend test P = 0.03). Compared with those individuals who didn't express any putative risk genotypes, individuals featuring all of the putative risk genotypes did experience a significantly greater cancer risk (OR = 2.43, 95% CI = 1.21-4.90), particularly for individuals suffering tumors located in the rectum (OR = 3.18, 95% CI = 1.29-7.82) and diagnosed prior to the age of 60 years (OR = 4.90, 95% CI = 1.72-14.0). CONCLUSIONS Our results suggest that DNA-repair pathways may simultaneously modulate the risk of colorectal cancer for the Taiwanese population, and, particularly for rectal cancer and younger patients.
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Affiliation(s)
- Chih-Ching Yeh
- Institute of Environmental Health, National Taiwan University College of Public Health, Taipei 100, Taiwan
- Institute of Environmental Health and Department of Risk Management, China Medical University College of Public Health, Taichung 404, Taiwan
| | - Fung-Chang Sung
- Institute of Environmental Health, National Taiwan University College of Public Health, Taipei 100, Taiwan
- Institute of Environmental Health and Department of Risk Management, China Medical University College of Public Health, Taichung 404, Taiwan
| | - Reiping Tang
- Colorectal Section, Chang Gung Memorial Hospital, Linkou, Taiwan
| | | | - Ling-Ling Hsieh
- Department of Public Health, Chang Gung University, Tao-Yuan 333, Taiwan
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Wu X, Roth JA, Zhao H, Luo S, Zheng YL, Chiang S, Spitz MR. Cell Cycle Checkpoints, DNA Damage/Repair, and Lung Cancer Risk. Cancer Res 2005. [DOI: 10.1158/0008-5472.349.65.1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Given that defects in cell cycle control and DNA repair capacity may contribute to tumorigenesis, we hypothesized that patients with lung cancer would be more likely than healthy controls to exhibit deficiencies in cell cycle checkpoints and/or DNA repair capacity as gauged by cellular response to in vitro carcinogen exposure. In an ongoing case-control study of 155 patients with newly diagnosed lung cancer and 153 healthy controls, we used the comet assay to investigate the roles of cell cycle checkpoints and DNA damage/repair capability in lung tumorigenesis. The median γ-radiation-induced and benzo(a)pyrene diol epoxide–induced Olive tail moments, the comet assay parameter for measuring DNA damage, were significantly higher in the case group (5.31 and 4.22, respectively) than in the control group (4.42 and 2.83, respectively; P < 0.001). Higher tail moments of γ-radiation and benzo(a)pyrene diol epoxide–induced comets were significantly associated with 2.32- and 4.49-fold elevated risks, respectively, of lung cancer. The median γ-radiation-induced increases of cells in the S and G2 phases were significantly lower in cases (22.2% and 12.2%, respectively) than in controls (31.1% and 14.9%, respectively; P < 0.001). Shorter durations of the S and G2 phases resulted in 4.54- and 1.85-fold increased risks, respectively, of lung cancer. Also observed were joint effects between γ-radiation-induced increases of S and G2 phase frequencies and mutagen-induced comets. In addition, we found that in controls, the S phase decreased as tail moment increased. This study is significant because it provides the first molecular epidemiologic evidence linking defects in cell cycle checkpoints and DNA damage/repair capacity to elevated lung cancer risk.
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Affiliation(s)
| | - Jack A. Roth
- 2Thoracic & Cardiovascular Surgery, University of Texas M.D. Anderson Cancer Center, Houston, Texas and
| | - Hua Zhao
- 1Epidemiology and Departments of
| | | | - Yun-Ling Zheng
- 3Cancer Genetics and Epidemiology Program, Lombardi Cancer Center, Georgetown University Medical Center, Washington, District of Columbia, USA
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Kleinsasser NH, Wallner BC, Wagner C, Kastenbauer ER, Harréus UA. DNA repair capacity in lymphocytes of nasopharyngeal cancer patients. Eur Arch Otorhinolaryngol 2004; 262:561-6. [PMID: 15619126 DOI: 10.1007/s00405-004-0872-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2004] [Accepted: 09/20/2004] [Indexed: 10/26/2022]
Abstract
Possible hereditary factors in the tumorigenesis of nasopharyngeal cancer (NPC) have not yet been clearly identified. In the present study, the DNA repair capacity of lymphocytes after exposure to the nitrosamine NDEA was quantified in order to elucidate whether this measure may be a factor in susceptibility to NPC. The alkaline single-cell microgel electrophoresis (Comet) assay was used to quantify chemically induced DNA damage and repair capacity in lymphocytes of 30 NPC patients (NPC) and 29 non-tumor donors (NTD). The induction of DNA single strand breaks, alkali labile and incomplete excision repair sites after exposure of lymphocytes to NDEA was assessed as differences between repair intervals of 0 min, 15 min, 30 min and 60 min, respectively. A RC(total) was assessed using the difference between the OTMs of 0 min of repair time and the 60-min repair interval for both groups. Repair capacities (RC) were calculated for the intervals according to the Olive Tail Moment (OTM), a quantitative measure for DNA migration in the Comet assay for the group of NPC patients and the NTD, accordingly. RCs were compared between the two groups using the Mann-Whitney U-Test. RC(15 min), RC(30 min) RC(60 min) and the RC(total) after a 60-min repair interval demonstrated no significant difference between the two groups. Furthermore, when comparing grades of DNA migration (OTM<2, 2-5, 5-10, 10-20, 20-30 and >30), there were no differences evident. In this investigation, rejoining of DNA single strand breaks in lymphocytes of NPC and NTD appeared to be accomplished to an equal degree and in equal time periods. However, the applied method does not give evidence concerning the quality of the single strand break rejoining processes. In this group of patients, tumorigenesis in NPC could not be associated with a decreased DNA repair capacity.
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Affiliation(s)
- Norbert H Kleinsasser
- Department of Otolaryngology and Head and Neck Surgery, University of Regensburg, Franz-Josef-Strauss Allee 11, 93053 Regensburg, Germany.
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Luna HS, Ferrari I, Luna H, McManus C, Padovani CR, Rumpf R. Differential susceptibility to chromatid breaks induced by bleomycin in sub-fertile and fertile bovines. Reprod Toxicol 2004; 19:97-101. [PMID: 15336717 DOI: 10.1016/j.reprotox.2004.05.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2003] [Revised: 04/23/2004] [Accepted: 05/11/2004] [Indexed: 11/30/2022]
Abstract
The rate of chromatid breaks was studied in cows with a history of sub-fertility by means of a test based on measurement of the average of breaks induced in lymphocytes of peripheral blood cultures. Fourteen female specimens were divided into two groups: fertile and sub-fertile. Peripheral blood lymphocytes were cultured and prepared for cytogenetic analysis. Two types of culture were established for each animal to evaluate the response of peripheral blood lymphocyte cultures to the genotoxic effects of bleomycin. The first culture did not receive bleomycin treatment (spontaneous chromosome aberrations). Our results showed that median breaks per cell (b/c) (+/-semirange) for spontaneous culture of the fertile and sub-fertile animals and bleomycin sensitivity assay for fertile and sub-fertile animals were 0.00+/-0.06, 0.02+/-0.03, 0.08+/-0.05 and 0.22+/-0.09, respectively. There was no significant difference (P>0.05) in the chromosomal breakage in lymphocytes not exposed to bleomycin; however, in comparing the number of chromatid breaks per cell in cultures treated with bleomycin, the sub-fertile group showed a significantly higher (P<0.05) level than the fertile group. These findings have implications both for identifying cattle with less than optimum fertility as well as for providing potential avenues to study the origins of sub-fertility.
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Affiliation(s)
- Hélder Silva Luna
- Department of Biosciences, Federal University of Mato Grosso do Sul, Aquidauana, MS, Brazil.
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60
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Blasiak J, Arabski M, Krupa R, Wozniak K, Rykala J, Kolacinska A, Morawiec Z, Drzewoski J, Zadrozny M. Basal, oxidative and alkylative DNA damage, DNA repair efficacy and mutagen sensitivity in breast cancer. Mutat Res 2004; 554:139-48. [PMID: 15450412 DOI: 10.1016/j.mrfmmm.2004.04.001] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2004] [Revised: 03/30/2004] [Accepted: 04/02/2004] [Indexed: 04/30/2023]
Abstract
Impaired DNA repair may fuel up malignant transformation of breast cells due to the accumulation of spontaneous mutations in target genes and increasing susceptibility to exogenous carcinogens. Moreover, the effectiveness of DNA repair may contribute to failure of chemotherapy and resistance of breast cancer cells to drugs and radiation. The breast cancer susceptibility genes BRCA1 and BRCA2 are involved in DNA repair. To evaluate further the role of DNA repair in breast cancer we determined: (1) the kinetics of removal of DNA damage induced by hydrogen peroxide and the anticancer drug doxorubicin, and (2) the level of basal, oxidative and alkylative DNA damage before and during/after chemotherapy in the peripheral blood lymphocytes of breast cancer patients and healthy individuals. The level of DNA damage and the kinetics of DNA repair were evaluated by alkaline single cell gel electrophoresis (comet assay). Oxidative and alkylative DNA damage were assayed with the use of DNA repair enzymes endonuclease III (Endo III) and formamidopyrimidine-DNA glycosylase (Fpg), recognizing oxidized DNA bases and 3-methyladenine-DNA glycosylase II (AlkA) recognizing alkylated bases. We observed slower kinetics of DNA repair after treatment with hydrogen peroxide and doxorubicin in lymphocytes of breast cancer patients compared to control individuals. The level of basal, oxidative and alkylative DNA damage was higher in breast cancer patients than in the control and the difference was more pronounced when patients after chemotherapy were engaged, but usually the level of DNA damage in these patients was too high to be measured with our system. Our results indicate that peripheral blood lymphocytes of breast cancer patients have more damaged DNA and display decreased DNA repair efficacy. Therefore, these features can be considered as risk markers for breast cancer, but the question whether they are the cause or a consequence of the illness remains open. Nevertheless, our results suggest that research on the mutagen sensitivity and efficacy of DNA repair could impact the development of new diagnostic and screening strategies as well as indicate new targets to prevent and cure cancer. Moreover, the comet assay may be applied to evaluate the suitability of a particular mode of chemotherapy to a particular cancer patient.
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Affiliation(s)
- Janusz Blasiak
- Department of Molecular Genetics, University of Lodz, ul. Banacha 12/16, 90-237, Poland.
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Branham MT, Nadin SB, Vargas-Roig LM, Ciocca DR. DNA damage induced by paclitaxel and DNA repair capability of peripheral blood lymphocytes as evaluated by the alkaline comet assay. Mutat Res 2004; 560:11-7. [PMID: 15099819 DOI: 10.1016/j.mrgentox.2004.01.013] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2003] [Revised: 01/23/2004] [Accepted: 01/29/2004] [Indexed: 10/26/2022]
Abstract
This study was designed to assess whether the chemotherapeutic drug paclitaxel can induce DNA damage in peripheral blood lymphocytes of human healthy donors, and to evaluate if such damage could be repaired. Venous blood was collected by routine venipuncture, the lymphocytes were isolated and cultured and then treated with 100nM, 500nM, 10microM, and 30microM of taxol for 4h. The alkaline comet assay technique was used to quantify the level of DNA damage and the DNA repair in lymphocytes. A significant increase in DNA damage was achieved when the cells were incubated with paclitaxel concentrations of 10microM or above. To test the DNA repair capability, the lymphocytes were allowed to recover for 2, 4, 6, and 24h. The DNA damage was almost completely repaired after 24h of incubation demonstrating a time-dependent repair capability. In conclusion, we demonstrate that paclitaxel induces DNA damage in peripheral blood lymphocytes and that this damage can be repaired.
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Affiliation(s)
- María Teresita Branham
- Institute of Experimental Medicine and Biology of Cuyo, Regional Center for Scientific and Technological Research and Argentine Foundation for Cancer Research, C.C. 855-5500 Mendoza, Argentina
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Kleinsasser NH, Wallner BC, Harréus UA, Zwickenpflug W, Richter E. Genotoxic effects of myosmine in human lymphocytes and upper aerodigestive tract epithelial cells. Toxicology 2003; 192:171-7. [PMID: 14580784 DOI: 10.1016/s0300-483x(03)00296-8] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Myosmine, 3-(1-pyrroline-2-yl)pyridine, is an alkaloid found in tobacco plants. Recently, it was also detected in various edibles and staple foods. Whereas other tobacco alkaloids such as nicotine and nornicotine and their nitrosation products, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and N'-nitrosonornicotine (NNN), have been widely discussed, the mutagenic impact of myosmine has not been investigated in detail. In the present study, possible genotoxic effects of myosmine were studied in human lymphocytes and nasal mucosal cells using the alkaline single cell microgel electrophoresis (Comet) assay. DNA single strand breaks, alkali labile sites and incomplete excision repair sites were expressed using the Olive tail moment (OTM). One hour incubation with myosmine at 0, 5, 10, 25 and 50 mM induced a low but significantly dose-dependent increase of DNA migration from 1.29 +/- 0.13 to 18.25 +/- 1.59 (OTM, mean +/- S.E., N=11) in lymphocytes. In nasal mucosal cells a similar although somewhat less extensive DNA damage from 1.17 +/- 0.12 to 21.67 +/- 2.97 (OTM, mean +/- S.E., N=10-11) was obtained after 1 h incubation with myosmine at 0, 10, 25, 50 and 100 mM. After prolonged incubation of human lymphocytes with 10mM myosmine for 1, 3, 6, and 24 h, a significant time-dependent increase of DNA migration from 3.45 +/- 0.43 to 57.77 +/- 8.24 (OTM, mean +/- S.E., N=4) was observed. Our data indicate that myosmine expresses significant genotoxic effects in human target cells of carcinogenesis. This result warrants further investigations on the impact of this dietary component on human health.
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Affiliation(s)
- Norbert H Kleinsasser
- Klinisch experimentelle Onkologie, Department of Otolaryngology-Head and Neck Surgery, Ludwig-Maximilians-University of Munich, Pettenkoferstr. 4a, D-80336 Munich, Germany.
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63
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Schabath MB, Spitz MR, Grossman HB, Zhang K, Dinney CP, Zheng PJ, Wu X. Genetic instability in bladder cancer assessed by the comet assay. J Natl Cancer Inst 2003; 95:540-7. [PMID: 12671022 DOI: 10.1093/jnci/95.7.540] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Latent genetic instability has been associated with an increased risk for several cancers. We used the comet assay (single-cell gel electrophoresis) to assess whether genetic instability, as reflected by susceptibility to DNA damage, was associated with the risk of bladder cancer in a case-control study. METHODS We used the comet assay to measure baseline and benzo[a]pyrene diol epoxide (BPDE)- and gamma-radiation-induced DNA damage in individual peripheral blood lymphocytes from 114 incident case patients with bladder cancer and 145 matched healthy control subjects. All subjects provided personal information, including smoking history. DNA damage was visualized with the comet assay and quantified by the Olive tail moment parameter, a relative measure. Multivariable analysis was used to assess relative risks for bladder cancer associated with DNA damage. All statistical tests were two-sided. RESULTS Baseline levels of DNA damage were statistically significantly higher in case patients (tail moment = 1.40) than in control subjects (tail moment = 1.21) (difference = 0.19, 95% confidence interval [CI] = 0.04 to 0.32; P =.015), as were gamma-radiation-induced (tail moment = 4.76 versus 4.22; difference = 0.54, 95% CI = 0.11 to 0.96; P =.013) and BPDE-induced (tail moment = 4.06 versus 3.45; difference = 0.61, 95% CI = 0.23 to 0.99; P =.002) DNA damage. When data were dichotomized at the median value for DNA damage in control subjects and adjusted for age, sex, ethnicity, and smoking status, an increased estimated relative risk of bladder cancer was statistically significantly associated with DNA damage at baseline (odds ratio [OR] = 1.84, 95% CI = 1.07 to 3.15) and after gamma-radiation (OR = 1.81, 95% CI = 1.04 to 3.14) but not after BPDE treatment (OR = 1.69, 95% CI = 0.98 to 2.93). CONCLUSION Latent genetic instability as measured by the comet assay is associated with an increased estimated relative risk of bladder cancer.
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Affiliation(s)
- Matthew B Schabath
- Department of Epidemiology, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA
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Rossi O, Filiberti R, Neri M, Biggi S, Satragno L, Puntoni R, Frosina G. Incision of AP sites in lung cancer patients: a pilot study. TERATOGENESIS, CARCINOGENESIS, AND MUTAGENESIS 2002; 22:251-6. [PMID: 12111709 DOI: 10.1002/tcm.10018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
DNA base excision repair (BER) removes frequent DNA lesions of either endogenous or exogenous origin. Some indications point to BER defects in lung cancer patients. We have investigated the ability of ten lung cancer patients to repair natural AP sites, the most frequent genetic lesion, using an in vitro assay in which peripheral blood lymphocytes (PBL) extracts incise randomly depurinated plasmid DNA. The median value of repair activity in patients was lower than that of matched controls but the difference did not reach significance. Unlike other BER enzymatic steps, marked defects in incision of AP sites may not be associated with lung carcinogenesis.
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Affiliation(s)
- Ottavio Rossi
- DNA Repair Unit, Mutagenesis Laboratory, Istituto Nazionale Ricerca Cancro, Genova, Italy
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Pastorelli R, Cerri A, Mezzetti M, Consonni E, Airoldi L. Effect of DNA repair gene polymorphisms on BPDE-DNA adducts in human lymphocytes. Int J Cancer 2002; 100:9-13. [PMID: 12115580 DOI: 10.1002/ijc.10463] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
To determine whether variations in DNA repair genes are related to host DNA damage, we investigated the association between polymorphism in the XPD gene (codon 199, 312, 751) and the XRCC1 gene (codon 194, 399) and the presence of benzo(a)pyrene diolepoxide adducts to lymphocyte DNA (BPDE-DNA) in a group of male patients with incident lung cancer, all current smokers. BPDE-DNA adducts were analyzed by high-resolution gas chromatography-negative ion chemical ionization-mass spectrometry. XPD and XRCC1 genotypes were identified by PCR-RFLP. XRCC1 and XPD genotypes did not affect the levels and proportion of detectable BPDE-DNA adducts. The patients were also genotyped for the GSTM1 polymorphism, given its role in the detoxification of BPDE. Individuals with the GSTM1 deletion had significantly higher levels of BPDE-DNA adducts when they were XPD-Asp312Asp+Lys751Lys than carriers of at least one variant allele. No such association was found with the XRCC1 genotypes. Because of the small study population (n = 60), further statistical analysis of possible gene-gene and gene-environment would not be informative. This is the first study analysing the specific BPDE-DNA adduct in vivo with regard to polymorphic repair genes (XPD, XRCC1) and xenobiotic metabolizing gene (GSTM1). Our results raise the possibility that the XPD-Asp312Asp+Lys751Lys genotype may increase BPDE-DNA damage; this effect might be evident in individuals who are especially likely to have accumulated damage, probably because of lower detoxification capacity and high environmental exposure.
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Affiliation(s)
- Roberta Pastorelli
- Laboratory of Molecular Toxicology, Department of Environmental Health Sciences, Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy.
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Rajaee-Behbahani N, Schmezer P, Ramroth H, Bürkle A, Bartsch H, Dietz A, Becher H. Reduced poly(ADP-ribosyl)ation in lymphocytes of laryngeal cancer patients: results of a case-control study. Int J Cancer 2002; 98:780-4. [PMID: 11920651 DOI: 10.1002/ijc.10234] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Poly(ADP-ribose) polymerase (PARP), a nuclear enzyme that is catalytically activated by DNA strand breaks, plays a complex role in DNA repair. Using NAD(+) as a precursor, it catalyzes the formation of ADP-ribose polymers, which are attached to various proteins. Defects in DNA repair pathways have been associated with increased risks for cancer in humans. We investigated whether differences in the activity of PARP are associated with the risk for laryngeal cancer. In a case-control study on genetic, lifestyle and occupational risk factors for laryngeal cancer, PARP activity was assessed as DNA damage-induced poly(ADP-ribose) formation in human peripheral blood lymphocytes by quantitative immunofluorescence analysis. Polymer formation was determined as the cellular response to bleomycin, a well-known inducer of DNA strand breaks, in lymphocytes from 69 laryngeal cancer patients and 125 healthy controls. The frequency of bleomycin-induced polymer formation, measured as mean pixel intensity, was significantly lower in cases (74.6, SE = 3.7) than in controls (94.5, SE = 3.5) and not influenced by smoking, age or sex. There was no significant difference between cases (59.1, SE = 5.2) and controls (50.5, SE = 3.7) in basal polymer formation (in cells not treated with bleomycin). When the highest tertile of polymer formation was used as the reference, the odds ratio for the lowest tertile of bleomycin-induced polymer formation was 3.79 (95% confidence interval 1.37-10.47, p = 0.01). Peripheral blood lymphocytes from laryngeal cancer patients thus showed significantly less bleomycin-induced poly(ADP-ribose) formation. Our results suggest that a reduced capacity of somatic cells to synthesize poly(ADP-ribose) might be associated with an increased risk for laryngeal cancer. The underlying mechanism remains to be investigated.
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Affiliation(s)
- Nahid Rajaee-Behbahani
- Division of Toxicology and Cancer Risk Factors, Deutsches Krebsforschungszentrum, Heidelberg, Germany
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Mayer C, Popanda O, Zelezny O, von Brevern MC, Bach A, Bartsch H, Schmezer P. DNA repair capacity after gamma-irradiation and expression profiles of DNA repair genes in resting and proliferating human peripheral blood lymphocytes. DNA Repair (Amst) 2002; 1:237-50. [PMID: 12509255 DOI: 10.1016/s1568-7864(01)00019-2] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
DNA repair plays an important role in maintaining genomic integrity, and deficiencies in repair function are known to promote cancer development. Several studies have used the individual capacity to repair DNA damage in peripheral blood lymphocytes (PBLs) as a cancer risk marker. As the cell's ability to remove DNA damage may be correlated with proliferative activity, it is an important question whether quiescent or dividing cells should be used in such studies. The aim of our study was to compare DNA repair capacity and expression profiles of 70 known DNA repair genes, both in resting and phytohemagglutinin (PHA) stimulated human PBLs. Using the comet assay, gamma-radiation-induced DNA damage and repair in lymphocytes was analyzed. No difference, neither in the rate of radiation-induced DNA damage nor in DNA repair capacity between PHA-stimulated and non-stimulated PBLs was observed. Stimulated cells, however, showed significantly elevated values for background damage. Transcriptional profiles of repair genes were analyzed using cDNA arrays. Hybridization experiments were performed with mRNA isolated from both unstimulated and PHA-stimulated PBLs. More than 70% of all evaluated genes had constant expression levels. Twelve genes responded with a more than two-fold increase of transcripts to the mitogenic stimulus. Most of the up-regulated repair enzymes are also known to play a role in DNA replication. In conclusion, the data presented here suggest that all repair proteins needed for the repair of gamma-irradiation induced DNA-damage, that can be detected by the alkaline comet assay, are already present in G0 cells at sufficient amounts and do not need to be induced once lymphocytes are stimulated to start cycling. Our results thus do not support a general increase in DNA repair activity of PBLs by PHA stimulation, and the use of stimulated PBLs in molecular epidemiological studies on DNA repair of gamma-irradiation induced DNA damage seems not to be mandatory.
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Affiliation(s)
- Claudia Mayer
- Division of Toxicology and Cancer Risk Factors, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany
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