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Oncotarget, 7, 75996--76005
2016

The prognostic value of DNA damage level in peripheral blood lymphocytes of chemotherapy-naïve patients with germ cell cancer.

Sestakova, Zuzana, Kalavska, Katarina, Hurbanova, Lenka, Jurkovicova, Dana, Gursky, Jan, Chovanec, Michal, Svetlovska, Daniela, Miskovska, Vera, Obertova, Jana, Palacka, Patrik, Rejlekova, Katarina, Sycova-Mila, Zuzana, Cingelova, Silvia, Spanik, Stanislav, Mardiak, Jozef, Chovanec, Miroslav, Mego, Michal

Germ cell tumors (GCTs) are extraordinarily sensitive to cisplatin (CDDP)-based chemotherapy. DNA damage represents one of the most important factors contributing to toxic effects of CDDP-based chemotherapy. This study was aimed to evaluate the prognostic value of DNA damage level in peripheral blood lymphocytes (PBLs) from chemo-naïve GCT patients. PBLs isolated from 59 chemotherapy-naïve GCT patients were included into this prospective study. DNA damage levels in PBLs were evaluated by the Comet assay and scored as percentage tail DNA by the Metafer-MetaCyte analyzing software. The mean ± SEM (standard error of the mean) of endogenous DNA damage level was 5.25 ± 0.64. Patients with DNA damage levels lower than mean had significantly better progression free survival (hazard ratio [HR] = 0.19, 95% CI (0.04 - 0.96), P = 0.01) and overall survival (HR = 0.00, 95% CI (0.00 - 0.0), P < 0.001) compared to patients with DNA damage levels higher than mean. Moreover, there was significant correlation between the DNA damage level and presence of mediastinal lymph nodes metastases, IGCCCG (International Germ Cell Cancer Collaborative Group) risk group, and serum tumor markers level. These data suggest that DNA damage levels in PBLs of GCT patients may serve as an important prognostic marker early identifying patients with poor outcome.

Digital object identifier (DOI): 10.18632/oncotarget.12515

Radiation research, 185, 658--667
2016

Telomere Length in Aged Mayak PA Nuclear Workers Chronically Exposed to Internal Alpha and External Gamma Radiation.

Scherthan, Harry, Sotnik, Natalia, Peper, Michel, Schrock, Gerrit, Azizova, Tamara, Abend, Michael

Telomeres consist of GC-rich DNA repeats and the "shelterin" protein complex that together protect chromosome ends from fusion and degradation. Telomeres shorten with age due to incomplete end replication and upon exposure to environmental and intrinsic stressors. Exposure to ionizing radiation is known to modulate telomere length. However, the response of telomere length in humans chronically exposed to radiation is poorly understood. Here, we studied relative telomere length (RTL) by IQ-FISH to leukocyte nuclei in a group of 100 workers from the plutonium production facility at the Mayak Production Association (PA) who were chronically exposed to alpha-emitting ((239)Pu) radiation and/or gamma (photon) radiation, and 51 local residents serving as controls, with a similar mean age of about 80 years. We applied generalized linear statistical models adjusted for age at biosampling and the second exposure type on a linear scale and observed an age-dependent telomere length reduction. In those individuals with the lowest exposure, a significant reduction of about 20% RTL was observed, both for external gamma radiation (≤1 Gy) and internal alpha radiation (≤0.05-0.1 Gy to the red bone marrow). In highly exposed individuals (>0.1 Gy alpha, 1-1.5 Gy gamma), the RTL was similar to control. Stratification by gender revealed a significant (∼30%) telomere reduction in low-dose-exposed males, which was absent in females. While the gender differences in RTL may reflect different working conditions, lifestyle and/or telomere biology, absence of a dose response in the highly exposed individuals may reflect selection against cells with short telomeres or induction of telomere-protective effects. Our observations suggest that chronic systemic exposure to radiation leads to variable dose-dependent effects on telomere length.

Digital object identifier (DOI): 10.1667/RR14271.1

J Neurosci Methods, 247, 41–49
May, 2015

Assessing fibrinogen extravasation into Alzheimer's disease brain using high-content screening of brain tissue microarrays.

Narayan, Pritika J., Kim, Sue-Ling, Lill, Claire, Feng, Sheryl, Faull, Richard L M., Curtis, Maurice A., Dragunow, Michael

Tissue microarrays are commonly used to evaluate disease pathology however methods to automate and quantify pathological changes are limited.This article demonstrates the utility of the VSlide scanner (MetaSystems) for automated image acquisition from immunolabelled tissue microarray slides, and subsequent automated image analysis with MetaXpress (Molecular Devices) software to obtain objective, efficient and reproducible data from immunolabelled tissue microarray sections.Significant increases in fibrinogen immunolabelling were observed in 29 Alzheimer's disease cases compared to 28 control cases analysed from a single tissue microarray slide. Western blot analysis also demonstrated significant increases in fibrinogen immunolabelling in 6 Alzheimer's cases compared to 6 control cases. The observed changes were also validated with gold standard blinded manual H-scoring.VSlide Metafer software offers a 'tissue microarray acquisition' plugin for easy mapping of tissue cores with their original position on the tissue microarray map. High resolution VSlide images are compatible with MetaXpress image analysis software. This article details the coupling of these two technologies to accurately and reproducibly analyse immunolabelled tissue microarrays within minutes, compared to the gold standard method of manual counting using H-scores which is significantly slower and prone to inter-observer variation.Here, we couple brain tissue microarray technology with high-content screening and automated image analysis as a powerful way to address bottle necks in data generation and improve throughput, as well as sensitivity to study biological/pathological changes in brain disease.

Digital object identifier (DOI): 10.1016/j.jneumeth.2015.03.017

Mutagenesis
April, 2015

Sesamol attenuates genotoxicity in bone marrow cells of whole-body γ-irradiated mice.

Arun Kumar, Tamizh G. Selvan, Akanchha M. Tripathi, Sandeep Choudhary, Shahanshah Khan, Jawahar S. Adhikari, Nabo K. Chaudhury

Ionising radiation causes free radical-mediated damage in cellular DNA. This damage is manifested as chromosomal aberrations and micronuclei (MN) in proliferating cells. Sesamol, present in sesame seeds, has the potential to scavenge free radicals; therefore, it can reduce radiation-induced cytogenetic damage in cells. The aim of this study was to investigate the radioprotective potential of sesamol in bone marrow cells of mice and related haematopoietic system against radiation-induced genotoxicity. A comparative study with melatonin was designed for assessing the radioprotective potential of sesamol. C57BL/6 mice were administered intraperitoneally with either sesamol or melatonin (10 and 20mg/kg body weight) 30min prior to 2-Gy whole-body irradiation (WBI) and sacrificed after 24h. Total chromosomal aberrations (TCA), MN and cell cycle analyses were performed using bone marrow cells. The comet assay was performed on bone marrow cells, splenocytes and lymphocytes. Blood was drawn to study haematological parameters. Prophylactic doses of sesamol (10 and 20mg/kg) in irradiated mice reduced TCA and micronucleated polychromatic erythrocyte frequency in bone marrow cells by 57\% and 50\%, respectively, in comparison with radiation-only groups. Sesamol-reduced radiation-induced apoptosis and facilitated cell proliferation. In the comet assay, sesamol (20mg/kg) treatment reduced radiation-induced comets (\% DNA in tail) compared with radiation only (P

Proc Natl Acad Sci U S A, 112(15), 4713–4718
April, 2015

Multiple mechanisms limit meiotic crossovers: TOP3alpha and two BLM homologs antagonize crossovers in parallel to FANCM.

Séguéla-Arnaud, Mathilde, Crismani, Wayne, Larchevêque, Cécile, Mazel, Julien, Froger, Nicole, Choinard, Sandrine, Lemhemdi, Afef, Macaisne, Nicolas, Van Leene, Jelle, Gevaert, Kris, De Jaeger, Geert, Chelysheva, Liudmilla, Mercier, Raphael

Meiotic crossovers (COs) have two important roles, shuffling genetic information and ensuring proper chromosome segregation. Despite their importance and a large excess of precursors (i.e., DNA double-strand breaks, DSBs), the number of COs is tightly regulated, typically one to three per chromosome pair. The mechanisms ensuring that most DSBs are repaired as non-COs and the evolutionary forces imposing this constraint are poorly understood. Here we identified Topoisomerase3α (TOP3α) and the RECQ4 helicases–the Arabidopsis slow growth suppressor 1 (Sgs1)/Bloom syndrome protein (BLM) homologs–as major barriers to meiotic CO formation. First, the characterization of a specific TOP3α mutant allele revealed that, in addition to its role in DNA repair, this topoisomerase antagonizes CO formation. Further, we found that RECQ4A and RECQ4B constitute the strongest meiotic anti-CO activity identified to date, their concomitant depletion leading to a sixfold increase in CO frequency. In both top3α and recq4ab mutants, DSB number is unaffected, and extra COs arise from a normally minor pathway. Finally, both TOP3α and RECQ4A/B act independently of the previously identified anti-CO Fanconi anemia of complementation group M (FANCM) helicase. This finding shows that several parallel pathways actively limit CO formation and suggests that the RECQA/B and FANCM helicases prevent COs by processing different substrates. Despite a ninefold increase in CO frequency, chromosome segregation was unaffected. This finding supports the idea that CO number is restricted not because of mechanical constraints but likely because of the long-term costs of recombination. Furthermore, this work demonstrates how manipulating a few genes holds great promise for increasing recombination frequency in plant-breeding programs.

Digital object identifier (DOI): 10.1073/pnas.1423107112

Stroke, 46(3), 835--842
March, 2015

Imaging of a clinically relevant stroke model: glucose hypermetabolismrevisited.

Fabian Arnberg, Jonas Grafstroem, Johan Lundberg, Sahar Nikkhou-Aski, Philip Little, Peter Damberg, Nicholas Mitsios, Jan Mulder, Li Lu, Michael Soederman, Sharon Stone-Elander, Staffan Holmin

Ischemic stroke has been shown to cause hypermetabolism of glucose in the ischemic penumbra. Experimental and clinical data indicate that infarct-related systemic hyperglycemia is a potential therapeutic target in acute stroke. However, clinical studies aiming for glucose control in acute stroke have neither improved functional outcome nor reduced mortality. Thus, further studies on glucose metabolism in the ischemic brain are warranted.We used a rat model of stroke that preserves collateral flow. The animals were analyzed by [2-(18)F]-2-fluoro-2-deoxy-d-glucose positron emission tomography or magnetic resonance imaging during 90-minute occlusion of the middle cerebral artery and during 60 minutes after reperfusion. Results were correlated to magnetic resonance imaging of cerebral blood flow, diffusion of water, lactate formation, and histological data on cell death and blood-brain barrier breakdown.We detected an increased [2-(18)F]-2-fluoro-2-deoxy-d-glucose uptake within ischemic regions succumbing to infarction and in the peri-infarct region. Magnetic resonance imaging revealed impairment of blood flow to ischemic levels in the infarct and a reduction of cerebral blood flow in the peri-infarct region. Magnetic resonance spectroscopy revealed lactate in the ischemic region and absence of lactate in the peri-infarct region. Immunohistochemical analyses revealed apoptosis and blood-brain barrier breakdown within the infarct.The increased uptake of [2-(18)F]-2-fluoro-2-deoxy-d-glucose in cerebral ischemia most likely reflects hypermetabolism of glucose meeting increased energy needs of ischemic and hypoperfused brain tissue, and it occurs under both anaerobic and aerobic conditions measured by local lactate production. Infarct-related systemic hyperglycemia could serve to facilitate glucose supply to the ischemic brain. Glycemic control by insulin treatment could negatively influence this mechanism.

Acta Neuropathol
February, 2015

Critical role of somatostatin receptor 2 in the vulnerability ofthe central noradrenergic system: new aspects on Alzheimer's disease.

Csaba Adori, Laura Glueck, Swapnali Barde, Takashi Yoshitake, Gabor G. Kovacs, Jan Mulder, Zsofia Magloczky, Laszlo Havas, Kata Boelcskei, Nicholas Mitsios, Mathias Uhlen, Janos Szolcsanyi, Jan Kehr, Annica Roennbaeck, Thue Schwartz, Jens F. Rehfeld, Tibor Harkany, Miklos Palkovits, Stefan Schulz, Tomas Hoekfelt

Alzheimer's disease and other age-related neurodegenerative disorders are associated with deterioration of the noradrenergic locus coeruleus (LC), a probable trigger for mood and memory dysfunction. LC noradrenergic neurons exhibit particularly high levels of somatostatin binding sites. This is noteworthy since cortical and hypothalamic somatostatin content is reduced in neurodegenerative pathologies. Yet a possible role of a somatostatin signal deficit in the maintenance of noradrenergic projections remains unknown. Here, we deployed tissue microarrays, immunohistochemistry, quantitative morphometry and mRNA profiling in a cohort of Alzheimer's and age-matched control brains in combination with genetic models of somatostatin receptor deficiency to establish causality between defunct somatostatin signalling and noradrenergic neurodegeneration. In Alzheimer's disease, we found significantly reduced somatostatin protein expression in the temporal cortex, with aberrant clustering and bulging of tyrosine hydroxylase-immunoreactive afferents. As such, somatostatin receptor 2 (SSTR2) mRNA was highly expressed in the human LC, with its levels significantly decreasing from Braak stages III/IV and onwards, i.e., a process preceding advanced Alzheimer's pathology. The loss of SSTR2 transcripts in the LC neurons appeared selective, since tyrosine hydroxylase, dopamine {\^a}-hydroxylase, galanin or galanin receptor 3 mRNAs remained unchanged. We modeled these pathogenic changes in Sstr2 (-/-) mice and, unlike in Sstr1 (-/-) or Sstr4 (-/-) genotypes, they showed selective, global and progressive degeneration of their central noradrenergic projections. However, neuronal perikarya in the LC were found intact until late adulthood (

Brain Struct Funct
January, 2015

Acute neuroinflammation in a clinically relevant focal cortical ischemicstroke model in rat: longitudinal positron emission tomography andimmunofluorescent tracking.

Miklos Toth, Philip Little, Fabian Arnberg, Jenny Haeggkvist, Jan Mulder, Christer Halldin, Balazs Gulyas, Staffan Holmin

Adequate estimation of neuroinflammatory processes following ischemic stroke is essential for better understanding of disease mechanisms, and for the development of treatment strategies. With the TSPO (18 kDa translocator protein) positron emission tomography (PET) radioligand [(11)C]PBR28, we monitored longitudinally the inflammatory response post-transient cerebral ischemia in rats, using a recently developed rat stroke model that produces isolated focal cortical infarcts with clinical relevance in size and pathophysiology. Six Sprague-Dawley rats were subjected to 90 min transient endovascular occlusion of the M2 segment of the middle cerebral artery (M2CAO). Animals were imaged with a nanoScan(®) PET/MRI system at 1, 4, 7 and 14 days after M2CAO with a bolus injection of [(11)C]PBR28. In the infarct region, we found a significantly increased uptake of [(11)C]PBR28 on day 4, 7 and 14 compared to day 1 as well as compared to the contralateral cortex. No significant increase was detected in the contralateral cortex during the 14 days of imaging. The activation in the infarct region gradually decreased between day 4 and day 14. In an additional group of animals (n = 26), immunofluorescence studies were performed with antibodies for activated microglia/monocytes (Cd11b), phagocytes (Cd68), astrocytes (glial fibrillary acidic protein) and TSPO. The TSPO immunofluorescence signal indicated reactive microgliosis post injury, corresponding to PET findings. The present clinically relevant animal model and TSPO PET ligand appear to be well suited for studies on neuroinflammation after ischemic stroke.

Cancers, 281-295
2015

A Novel Three-Colour Fluorescence in Situ Hybridization Approach for the Detection of t(7;12)(q36;p13) in Acute Myeloid Leukaemia Reveals New Cryptic Three Way Translocation t(7;12;16)

Abdulbasit Naiel, Michael Vetter, Olga Plekhanova, Elena Fleischman, Olga Sokova, Grigory Tsaur, Jochen Harbott, Sabrina Tosi

The t(7;12)(q36;p13) translocation is a recurrent chromosome abnormality that involves the ETV6 gene on chromosome 12 and has been identified in 20-30% of infant patients with acute myeloid leukaemia (AML). The detection of t(7;12) rearrangements relies on the use of fluorescence in situ hybridization (FISH) because this translocation is hardly visible by chromosome banding methods. Furthermore, a fusion transcript HLXB9-ETV6 is found in approximately 50% of t(7;12) cases, making the reverse transcription PCR approach not an ideal screening method. Considering the report of few cases of variant translocations harbouring a cryptic t(7;12) rearrangement, we believe that the actual incidence of this abnormality is higher than reported to date. The clinical outcome of t(7;12) patients is believed to be poor, therefore an early and accurate diagnosis is important in the clinical management and treatment. In this study, we have designed and tested a novel three-colour FISH approach that enabled us not only to confirm the presence of the t(7;12) in a number of patients studied previously, but also to identify a cryptic t(7;12) as part of a complex rearrangement. This new approach has proven to be an efficient and reliable method to be used in the diagnostic setting.

Trends in Cancer Research
2015

Fluorescence in situ hybridisation assays designed for del(7q) detection uncover more complex rearrangements in myeloid leukaemia cell lines

Yasser Mostafa Kamel, Abdulbasit Naiel, Areej Alshehri, Michael Vetter, Salvatore Saccone, Rhona Anderson, Sabrina Tosi

Fluorescence in situ hybridisation assays designed for del(7q) detection uncover more complex rearrangements in myeloid leukaemia cell lines ABSTRACT Chromosome 7 abnormalities are associated with poor prognosis in myeloid leukaemia. The pathogenetic mechanisms chromosome 7 rearrangements and lead to malignancy are still poorly understood. The use of leukaemia- derived cell lines might be a useful tool to shed some light on these mechanisms. The cytogenetic characterisation of these cell lines is therefore important for the understanding of the genetic alterations leading to the disease. We carried out fluorescence in situ hybridisation (FISH) on three different myeloid leukaemia-derived cell lines (GDM-1, GF-D8 and K562). These were selected on the basis of harbouring rearrangements of chromosome 7. The probes used in these experiments were whole and partial chromosome paints, Multiplex-fluorescence in situ hybridisation (M-FISH) probes as well as locus specific probes for the 7q22, 7q31 and 7q36 regions. Our study confirmed the chromosome 7 abnormalities previously reported in the cell lines GDM-1 and GF-D8. We refined one of the rearrangements of chromosome 7 in the K562 cell line and reported some discrepancies with the data published in earlier reports. With this study, we confirm the importance of using a series of FISH that arise from probes to characterise chromosomal abnormalities in detail, as some rearrangements might go under-detected or mis-interpreted. Moreover, we highlight the importance of monitoring cell lines broadly used in research, as these can lose or acquire characteristics as they evolve in time in different laboratories.

Cytogenet Genome Res, 147(2-3), 144–153
2015

Comparative Cytogenetics of the Congo African Grey Parrot (Psittacus erithacus).

Seibold-Torres, Cassandra, Owens, Elaine, Chowdhary, Renuka, Ferguson-Smith, Malcolm A., Tizard, Ian, Raudsepp, Terje

The Congo African grey parrot (Psittacus erithacus, PER) is an endemic species of Central Africa, valued for its intelligence and listed as vulnerable due to poaching and habitat destruction. Improved knowledge about the P. erithacus genome is needed to address key biological questions and conservation of this species. The P. erithacus genome was studied using conventional and molecular cytogenetic approaches including Zoo-FISH. P. erithacus has a 'typical' parrot karyotype with 2n = 62-64 and 8 pairs of macrochromosomes. A distinct feature was a sharp macro-microchromosome boundary. Telomeric sequences were present at all chromosome ends and interstitially in PER2q, the latter coinciding with a C-band. NORs mapped to 4 pairs of microchromosomes which is in contrast to a single NOR in ancestral type avian karyotypes. Zoo-FISH with chicken macrochromosomes GGA1-9 and Z revealed patterns of conserved synteny similar to many other avian groups, though neighboring synteny combinations of GGA6/7, 8/9, and 1/4 were distinctive only to parrots. Overall, P. erithacus shared more Zoo-FISH patterns with neotropical macaws than Australian species such as cockatiel and budgerigar. The observations suggest that Psittaciformes karyotypes have undergone more extensive evolutionary rearrangements compared to the majority of other avian genomes.

Digital object identifier (DOI): 10.1159/000444136

Blood Cancer J, 5, e374
2015

Four genetic lymphoma-specific events (MYC, BCL2, BCL6 and CCND1) identified in a high grade B lymphoma case.

Ittel, A., Hélias, C., Wissler, M. P., Toussaint, E., Miguet, L., Chenard, M. P., Monier, L., Gervais, C., Mauvieux, L.

In the WHO classification, double or triple-hit lymphoma depicts rare and aggressive lymphomas displaying BCL2 and/or MYC and/or BCL6 gene rearrangements that are categorized as B-cell lymphomas unclassified, with features intermediate between diffuse B-cell lymphoma and Burkitt lymphoma. Bacher et al.2 described an interesting series of 10 cases of such neoplasms. In addition, they reported the two first cases displaying four different lymphoma-specific events (quadruple hit) involving the genes MYC, BCL2, BCL6 and CCND1. We describe here a third case occurring in a 79-year-old male patient suffering from paraesthesias for 4 months who was referred for polyneuritis in a context of poor general condition. Clinical examination showed the presence of numerous axillary, supraclavicular, mediastinal and inguinal lymphadenopathies, neuro-meningeal invasion and skin infiltration. The biopsy of a left arm skin nodule revealed large proliferating cells (Ki-67 80%) stained by anti-CD20, BCL2 and BCL6 antibodies, CD10 and CD23 remaining negative, consistent with the diagnosis of diffuse large B-cell lymphoma (DLBCL), not otherwise specified. Blood cell counts showed 8.1 × 109/l leukocytes, 13.2 g/dl hemoglobin, 166 × 109/l platelets. LDH and β-2 microglobulin were elevated (989 U/I and 9.14 mg/l, respectively). Blood cell film examination showed the presence of 28% abnormal lymphocytes (medium sized, with intense basophilia, irregular nuclear contours, slightly clumped chromatin and frequent prominent nucleoli) suggestive of a high grade lymphoma. Flow cytometry revealed a lambda immunoglobulin light chain restriction. These cells expressed pan-B markers such as CD19, CD20, FMC7, CD22, with weak CD5 and CD43 positivity. CD10 and 23 were negative. Both the morphology and immunophenotype of the blood cells favored a pleomorphic mantle cell lymphoma (MCL) aggressive variant diagnosis. Cytogenetic study performed in the WBCs found a complex hyperdiploid karyotype (47 chromosomes, Figure 1) with a t(3;22) translocation involving the BCL6 and IGL genes, a structural abnormality of chromosome 8 resulting in juxtaposition of 5′ MYC and BCL2 in fluorescence in situ hybridization (with break of the MYC probe), a derivative chromosome 18 from a t(14;18) translocation with fusion of 5′IGH and BCL2, and a t(11;14) complex translocation involving IGH and CCND1 (Figure 2). Other numeral (trisomy 12) and structural abnormalities (involving the 1, 7, 14 and 21 chromosomes) were also detected (Figure 1). Overexpression of cyclin D1 was detected in the WBCs by real-time quantitative PCR, as well as in the skin lesion using immunochemistry. Anti-SOX11 antibody staining was found to be negative. Chemotherapy combining rituximab, ifosfamide, cytosine arabinoside and intrathecal methotrexate was initiated, but the patient died 4 months after the diagnosis. This third case of quadruple-hit lymphoma underlines the complexity of the classification of such aggressive malignancies. Initial rearrangement of the CCND1 gene characterizes MCL that may harbor in very rare cases additional rearrangements of MYC or BCL6, but histological transformation to typical large cell lymphoma is not retained in the WHO classification. In addition, cyclin D1 overexpression is considered to be a rare feature in DLBCL. Recently, Ok et al.3 proposed to reclassify DLBCL with expression of cyclin D1, CCND1 chromosomal rearrangement and CD5 positivity as an aggressive pleomorphic MCL variant. However, no observation of multiple lymphoma-specific gene rearrangements was described in that study. Juskevicius et al.4 suggest the existence of a ‘gray zone’ in which morphologic, clinical and genetic features are insufficient to segregate lymphomas with overexpression of cyclin D1/translocations involving CCND1 between blastoid MCL and cyclin D1-positive DLBCL. Regarding the immunophenotyping and molecular data, our case is possibly a genetically unstable aggressive pleomorphic MCL variant, which acquired three additional genetic hits.

Digital object identifier (DOI): 10.1038/bcj.2015.99

Molecular cytogenetics, 8, 79
2015

Karyotype alteration generates the neoplastic phenotypes of SV40-infected human and rodent cells.

Bloomfield, Mathew, Duesberg, Peter

Despite over 50 years of research, it remains unclear how the DNA tumor viruses SV40 and Polyoma cause cancers. Prevailing theories hold that virus-coded Tumor (T)-antigens cause cancer by inactivating cellular tumor suppressor genes. But these theories don't explain four characteristics of viral carcinogenesis: (1) less than one in 10,000 infected cells become cancer cells, (2) cancers have complex individual phenotypes and transcriptomes, (3) recurrent tumors without viral DNA and proteins, (4) preneoplastic aneuploidies and immortal neoplastic clones with individual karyotypes. As an alternative theory we propose that viral carcinogenesis is a form of speciation, initiated by virus-induced aneuploidy. Since aneuploidy destabilizes the karyotype by unbalancing thousands of genes it catalyzes chain reactions of karyotypic and transcriptomic evolutions. Eventually rare karyotypes evolve that encode cancer-specific autonomy of growth. The low probability of forming new autonomous cancer-species by random karyotypic and transcriptomic variations predicts individual and clonal cancers. Although cancer karyotypes are congenitally aneuploid and thus variable, they are stabilized or immortalized by selections for variants with cancer-specific autonomy. Owing to these inherent variations cancer karyotypes are heterogeneous within clonal margins. To test this theory we analyzed karyotypes and phenotypes of SV40-infected human, rat and mouse cells developing into neoplastic clones. In all three systems we found (1) preneoplastic aneuploidies, (2) neoplastic clones with individual clonal but flexible karyotypes and phenotypes, which arose from less than one in 10,000 infected cells, survived over 200 generations, but were either T-antigen positive or negative, (3) spontaneous and drug-induced variations of neoplastic phenotypes correlating 1-to-1 with karyotypic variations. Since all 14 virus-induced neoplastic clones tested contained individual clonal karyotypes and phenotypes, we conclude that these karyotypes have generated and since maintained these neoplastic clones. Thus SV40 causes cancer indirectly, like carcinogens, by inducing aneuploidy from which new cancer-specific karyotypes evolve automatically at low rates. This theory explains the (1) low probability of carcinogenesis per virus-infected cell, (2) the individuality and clonal flexibility of cancer karyotypes, (3) recurrence of neoplasias without viral T-antigens, and (4) the individual clonal karyotypes, transcriptomes and immortality of virus-induced neoplasias - all unexplained by current viral theories.

Digital object identifier (DOI): 10.1186/s13039-015-0183-y

Dental materials : official publication of the Academy of Dental Materials, 31, 1335--1344
2015

Dental composite components induce DNA-damage and altered nuclear morphology in gingiva fibroblasts.

Styllou, Marianthi, Reichl, Franz-Xaver, Styllou, Panorea, Urcan, Ebru, Rothmund, Lena, Hickel, Reinhard, Högg, Christof, Scherthan, Harry

Released dental composite components can damage human gingival fibroblasts (HGFs) and their DNA. The cytotoxicity, chromatin condensation and the induction of DNA double strand breaks (DSBs) by different compounds of dental composites was investigated using an improved γ-H2AX focus assay. HGFs were incubated with the monomers: bisphenol-A-ethoxylate-dimethacrylate (Bis-DMA), bisphenol-A-glycerolate-dimethacrylate (BisGMA), ethyltriethylen glycol methacrylate (ETEGMA), glycidyl methacrylate (GMA), 1,6-hexandiol-dimethycrylate (HDDMA), trimethylolpropane ethoxylate triacrylate (TMPTA), and acrylamide (ACR). DSBs were determined by enumerating γ-H2AX and 53BP1 foci colocalized at DSBs. A concentration-dependent induction of DSBs was found in the order: GMA>BisGMA>ACR>Bis-DMA>HDDMA>TMPTA>ETEGMA. HGFs exposure to GMA (0.3mM) and to BisGMA (0.09mM) induced the highest rate of DSB foci, i.e. 12-fold and 8-fold, respectively, relative to control (0.33 DSB foci/cell). At the highest concentrations (EC50) prominent changes in the chromatin morphology of HGF cell nuclei, i.e. compaction of nuclear chromatin and reduction of the area covered by the ovoid fibroblast nuclei, were observed. Nuclear condensation was significantly induced by GMA (1.7-fold at 0.3mM) and BisGMA (1.6-fold at 0.09mM), which correlated with the highest numbers of induced DSB foci (GMA, BisGMA, 3.9 and 2.6 foci/cell, respectively). The improved γ-H2AX/53BP1 focus assay revealed a concentration-dependent increase in DSBs for all tested substances. Furthermore, concentration-dependent changes in HGF cell nucleus morphology was noted, demonstrating genotoxic effects of the substances tested.

Digital object identifier (DOI): 10.1016/j.dental.2015.08.156

Prenat Diagn, 34(11), 1066--1072
November, 2014

A new marker set that identifies fetal cells in maternal circulationwith high specificity.

Lotte Hatt, Marie Brinch, Ripudaman Singh, Kristine M{\o}ller, Rune Hoff Lauridsen, Jacob M{\o}rup Schl{\"u}tter, Niels Uldbjerg, Britta Christensen, Steen K{\o}lvraa

Fetal cells from the maternal circulation (FCMBs) have the potential to replace cells from amniotic fluid or chorionic villi in a diagnosis of common chromosomal aneuploidies. Good markers for enrichment and identification are lacking.Blood samples from 78 normal pregnancies were used for testing the marker-set CD105 and CD141 for fetal cell enrichment. Fetal cell candidates were subsequently stained by a cocktail of cytokeratin antibodies, and the gender of the fetal cells was explored by fluorescence in situ hybridization (FISH) of the X and Y chromosomes.Fetal cell candidates could be detected in 91\% of the samples, and in 85\% of the samples, it was possible to obtain X and Y chromosomal FISH results for gender determination. The concordance between gender determined by FISH on fetal cells in maternal blood and gender found at birth reached 100\% if three or more fetal cells with FISH signals could be found in a sample.The marker set identifies fetal cells with specificity high enough to make cell-based noninvasive prenatal diagnosis realistic.

Nat Genet, 46(11), 1239--1244
November, 2014

Mutations in SPRTN cause early onset hepatocellular carcinoma, genomicinstability and progeroid features.

Davor Lessel, Bruno Vaz, Swagata Halder, Paul J. Lockhart, Ivana Marinovic-Terzic, Jaime Lopez-Mosqueda, Melanie Philipp, Joe C H. Sim, Katherine R. Smith, Judith Oehler, Elisa Cabrera, Raimundo Freire, Kate Pope, Amsha Nahid, Fiona Norris, Richard J. Leventer, Martin B. Delatycki, Gotthold Barbi, Simon {von Ameln}, Josef H{\"o}gel, Marina Degoricija, Regina Fertig, Martin D. Burkhalter, Kay Hofmann, Holger Thiele, Janine Altm{\"u}ller, Gudrun N{\"u}rnberg, Peter N{\"u}rnberg, Melanie Bahlo, George M. Martin, Cora M. Aalfs, Junko Oshima, Janos Terzic, David J. Amor, Ivan Dikic, Kristijan Ramadan, Christian Kubisch

Age-related degenerative and malignant diseases represent major challenges for health care systems. Elucidation of the molecular mechanisms underlying carcinogenesis and age-associated pathologies is thus of growing biomedical relevance. We identified biallelic germline mutations in SPRTN (also called C1orf124 or DVC1) in three patients from two unrelated families. All three patients are affected by a new segmental progeroid syndrome characterized by genomic instability and susceptibility toward early onset hepatocellular carcinoma. SPRTN was recently proposed to have a function in translesional DNA synthesis and the prevention of mutagenesis. Our in vivo and in vitro characterization of identified mutations has uncovered an essential role for SPRTN in the prevention of DNA replication stress during general DNA replication and in replication-related G2/M-checkpoint regulation. In addition to demonstrating the pathogenicity of identified SPRTN mutations, our findings provide a molecular explanation of how SPRTN dysfunction causes accelerated aging and susceptibility toward carcinoma.

Toxicol Sci, 140(1), 103--117
July, 2014

The gamma-H2AX Assay for Genotoxic and Nongenotoxic Agents: Comparisonof H2AX Phosphorylation with Cell Death Response.

Teodora Nikolova, Mirek Dvorak, Fabian Jung, Isabell Adam, Elisabeth Kr{\"a}mer, Aslihan Gerhold-Ay, Bernd Kaina

DNA double-strand breaks (DSBs) and blocked replication forks resulting from bulky adducts and inhibitors of replication activate the DNA damage response (DDR), a signaling pathway marked by phosphorylation of histone 2AX (H2AX). The phosphorylated form, gamma-H2AX, accumulates at the site of the damage and can be visualized as foci by immunocytochemistry. The objective of this study was to assess if gamma-H2AX is a reliable biomarker for genotoxic exposures. To this end, we selected 14 well-known genotoxic compounds and compared them with 10 nongenotoxic chemicals, using CHO-9 cells because they are well characterized as to DNA repair and DDR. We quantified gamma-H2AX foci manually and automatically. In addition, total gamma-H2AX activation was determined by flow cytometry. For all chemicals the cytotoxic dose response was assayed by a metabolic cytotoxicity assay. We show that (1) all genotoxic agents induced ?H2AX dose-dependently whereas nongenotoxic agents do not; (2) gamma-H2AX was observed for genotoxicants in the cytotoxic dose range, revealing a correlation between cytotoxicity and gamma-H2AX for genotoxic agents; for nongenotoxic agents cytotoxicity was not related to gamma-H2AX; (3) manual scoring of gamma-H2AX and automated scoring provided comparable results, the automated scoring was faster and investigator independent; (4) data obtained by foci counting and flow cytometry showed a high correlation, suggesting that gamma-H2AX scoring by flow cytometry has the potential for high-throughput analysis. However, the microscopic evaluation can provide additional information as to foci size, distribution, colocalization and background staining; (5) gamma-H2AX foci were colocalized with 53BP1 and Rad51, supporting the notion that they represent true DSBs. Collectively, the automated analysis of gamma-H2AX foci allows for rapid determination of genetic damage in mammalian cells. The data revealed that the induction of gamma-H2AX by genotoxicants is related to loss of viability and support gamma-H2AX as a reliable bio-indicator for pretoxic DNA damage.

Mutagenesis, 29(3), 165--175
May, 2014

Automation and validation of micronucleus detection in the 3D EpiDerm?human reconstructed skin assay and correlation with 2D dose responses.

K. E. Chapman, A. D. Thomas, J. W. Wills, S. Pfuhler, S. H. Doak, G J S. Jenkins

Recent restrictions on the testing of cosmetic ingredients in animals have resulted in the need to test the genotoxic potential of chemicals exclusively in vitro prior to licensing. However, as current in vitro tests produce some misleading positive results, sole reliance on such tests could prevent some chemicals with safe or beneficial exposure levels from being marketed. The 3D human reconstructed skin micronucleus (RSMN) assay is a promising new in vitro approach designed to assess genotoxicity of dermally applied compounds. The assay utilises a highly differentiated in vitro model of the human epidermis. For the first time, we have applied automated micronucleus detection to this assay using MetaSystems Metafer Slide Scanning Platform (Metafer), demonstrating concordance with manual scoring. The RSMN assay's fixation protocol was found to be compatible with the Metafer, providing a considerably shorter alternative to the recommended Metafer protocol. Lowest observed genotoxic effect levels (LOGELs) were observed for mitomycin-C at 4.8 ?g/ml and methyl methanesulfonate (MMS) at 1750 ?g/ml when applied topically to the skin surface. In-medium dosing with MMS produced a LOGEL of 20 ?g/ml, which was very similar to the topical LOGEL when considering the total mass of MMS added. Comparisons between 3D medium and 2D LOGELs resulted in a 7-fold difference in total mass of MMS applied to each system, suggesting a protective function of the 3D microarchitecture. Interestingly, hydrogen peroxide (H2O2), a positive clastogen in 2D systems, tested negative in this assay. A non-genotoxic carcinogen, methyl carbamate, produced negative results, as expected. We also demonstrated expression of the DNA repair protein N-methylpurine-DNA glycosylase in EpiDerm?. Our preliminary validation here demonstrates that the RSMN assay may be a valuable follow-up to the current in vitro test battery, and together with its automation, could contribute to minimising unnecessary in vivo tests by reducing in vitro misleading positives.

J Radiat Res
April, 2014

Biodosimetry estimation using the ratio of the longest:shortest lengthin the premature chromosome condensation (PCC) method applying autocaptureand automatic image analysis.

Jorge E. Gonz{\'a}lez, Ivonne Romero, Eric Gregoire, C{\'e}cile Martin, Ana I. Lamadrid, Philippe Voisin, Joan-Francesc Barquinero, Omar Garc{\'i}a

The combination of automatic image acquisition and automatic image analysis of premature chromosome condensation (PCC) spreads was tested as a rapid biodosimeter protocol. Human peripheral lymphocytes were irradiated with (60)Co gamma rays in a single dose of between 1 and 20 Gy, stimulated with phytohaemaglutinin and incubated for 48 h, division blocked with Colcemid, and PCC-induced by Calyculin A. Images of chromosome spreads were captured and analysed automatically by combining the Metafer 4 and CellProfiler platforms. Automatic measurement of chromosome lengths allows the calculation of the length ratio (LR) of the longest and the shortest piece that can be used for dose estimation since this ratio is correlated with ionizing radiation dose. The LR of the longest and the shortest chromosome pieces showed the best goodness-of-fit to a linear model in the dose interval tested. The application of the automatic analysis increases the potential use of the PCC method for triage in the event of massive radiation causalities.

J Trop Pediatr, 60(2), 134–140
April, 2014

Effect of therapeutic hypothermia on DNA damage and neurodevelopmental outcome among term neonates with perinatal asphyxia: a randomized controlled trial.

Gane, Bahubali D., Bhat, Vishnu, Rao, Ramachandra, Nandhakumar, S., Harichandrakumar, K. T., Adhisivam, B.

To study the effect of therapeutic hypothermia (TH) on deoxyribonucleic acid (DNA) damage and the neurodevelopmental outcome in term babies with perinatal asphyxia.Babies in the hypothermia group were cooled for the first 72 h, using gel packs. Rectal temperature of 33-34°C was maintained. Blood sample was collected before, at 36 h and after completion of TH for assessment of comet assay and 8-hydroxy2-deoxyguanosine (8-OHdG). Infants were followed up till 12 months.Baseline parameters were similar. After 72 h, the hypothermia group showed lower olive tail moment (12.88 ± 2.14) than the control group (22.16 ± 5.26) (p < 0.001). 8-HDG levels increased significantly in the control group (1252.87 ± 357.07) as compared to the hypothermia group (757.03 ± 198.49) (p < 0.001). Neurodevelopmental assessment at 12 months showed significantly low motor and mental developmental quotient in the control than hypothermia group.TH reduces oxidative stress-induced DNA damage and improves neurodevelopmental outcome. <Trial registration No: CTRI/2011/10/002094>

Digital object identifier (DOI): 10.1093/tropej/fmt098