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Foster N.,Ninewells Hospital and Medical School | Paulsson K.,Lund University | Sales M.,Ninewells Hospital and Medical School | Cunningham J.,Ninewells Hospital and Medical School | And 9 more authors.
British Journal of Haematology | Year: 2010

A proportion of cytogenetic abnormalities in myelodysplastic syndromes (MDS) and acute myeloid leukaemia (AML) may escape detection by high-resolution genomic technologies, but can be identified by conventional cytogenetic and molecular analysis. Here, we report the detection of a reciprocal translocation t(7;21)(p22;q22) in the marrow of two adults with MDS and AML, using conventional cytogenetic analysis and fluorescence-in situ-hybridization (FISH). Reverse-transcription polymerase chain reaction (RT-PCR) and sequence analysis identified a fusion between RUNX1 and the gene encoding ubiquitin specific peptidase-42 (USP42), with splice-variants and variable break-points within RUNX1. Combined cytomorphology and FISH studies in MDS marrow revealed abnormal RUNX1 signals within megakaryocytes, suggesting that the acquisition of t(7;21)(p22;q22) does not confer complete differentiation arrest and may represent an early genetic event in leukaemogenesis. Single nucleotide polymorphism-arrays failed to detect additional sub-microscopic genomic changes predisposing to or associated with t(7;21). Molecular analysis of 100 MDS and AML marrow specimens by RT-PCR did not reveal new cases with the RUNX1-USP42 fusion. Thus, our studies have identified t(7;21)(p22;q22) as a rare but recurrent abnormality in MDS/AML, with the existence of alternative spliced forms of the RUNX1-USP42 transcript in different patients. Further studies are required to identify the potential contribution of these splice-variants to disease heterogeneity. © 2010 Blackwell Publishing Ltd.

South A.P.,Center for Oncology and Molecular Medicine | O'Toole E.A.,Blizard Institute of Cell and Molecular Science
Dermatologic Clinics | Year: 2010

Patients with recessive dystrophic epidermolysis bullosa develop numerous life-threatening skin cancers. The reasons for this remain unclear. Parallels exist with other scarring skin conditions, such as Marjolin ulcer. We summarize observational and experimental data and discuss proposed theories for the development of such aggressive skin cancers. A context-driven situation seems to be emerging, but more focused research is required to elucidate the pathogenesis of epidermolysis bullosa-associated squamous cell carcinoma. © 2010 Elsevier Inc. All rights reserved.

Tummala H.,University of Abertay Dundee | Fleming S.,Center for Oncology and Molecular Medicine | Hocking P.M.,Roslin Institute | Wehner D.,University of Abertay Dundee | And 5 more authors.
PLoS ONE | Year: 2011

Background: The GNB3 gene is expressed in cone but not rod photoreceptors of vertebrates, where it acts as the β transducin subunit in the colour visual transduction process. A naturally occurring mutation 'D153del' in the GNB3 gene causes the recessively inherited blinding phenotype retinopathy globe enlarged (rge) disease in chickens. GNB3 is however also expressed in most other vertebrate tissues suggesting that the D153del mutation may exert pathological effects that outlie from eye. Principal Findings: Recombinant studies in COS-7 cells that were transfected with normal and mutant recombinant GNB3 constructs and subjected to cycloheximide chase showed that the mutant GNB3d protein had a much shorter half life compared to normal GNB3. GNB3 codes for the Gβ3 protein subunit that, together with different Gγ and Gα subunits, activates and regulates phosphorylation cascades in different tissues. As expected, the relative levels of cGMP and cAMP secondary messengers and their activated kinases such as MAPK, AKT and GRK2 were also found to be altered significantly in a tissue specific manner in rge chickens. Histochemical analysis on kidney tissue sections, from rge homozygous affected chickens, showed the chickens had enlargement of the glomerular capsule, causing glomerulomegaly and tubulointerstitial inflammation whereas other tissues (brain, heart, liver, pancreas) were unaffected. Significance: These findings confirm that the D153del mutation in GNB3 gene targets GNB3 protein to early degradation. Lack of GNB3 signalling causes reduced phosphorylation activity of ERK2 and AKT leading to severe pathological phenotypes such as blindness and renal abnormalities in rge chickens. © 2011 Tummala et al.

Marcel V.,Center for Oncology and Molecular Medicine | Fernandes K.,Center for Oncology and Molecular Medicine | Terrier O.,Center for Oncology and Molecular Medicine | Lane D.P.,P53 Laboratory P53Lab | Bourdon J.-C.,Center for Oncology and Molecular Medicine
Cell Death and Differentiation | Year: 2014

In addition to the tumor suppressor p53 protein, also termed p53α, the TP53 gene produces p53β and p53γ through alternative splicing of exons 9β and 9γ located within TP53 intron 9. Here we report that both TG003, a specific inhibitor of Cdc2-like kinases (Clk) that regulates the alternative splicing pre-mRNA pathway, and knockdown of SFRS1 increase expression of endogenous p53β and p53γ at mRNA and protein levels. Development of a TP53 intron 9 minigene shows that TG003 treatment and knockdown of SFRS1 promote inclusion of TP53 exons 9β/9γ. In a series of 85 primary breast tumors, a significant association was observed between expression of SFRS1 and α variant, supporting our experimental data. Using siRNA specifically targeting exons 9β/9γ, we demonstrate that cell growth can be driven by modulating p53β and p53γ expression in an opposite manner, depending on the cellular context. In MCF7 cells, p53β and p53γ promote apoptosis, thus inhibiting cell growth. By transient transfection, we show that p53β enhanced p53α transcriptional activity on the p21 and Bax promoters, while p53γ increased p53α transcriptional activity on the Bax promoter only. Moreover, p53β and p53γ co-immunoprecipitate with p53α only in the presence of p53-responsive promoter. Interestingly, although p53β and p53γ promote apoptosis in MCF7 cells, p53β and p53γ maintain cell growth in response to TG003 in a p53α-dependent manner. The dual activities of p53β and p53γ isoforms observed in non-treated and TG003-treated cells may result from the impact of TG003 on both expression and activities of p53 isoforms. Overall, our data suggest that p53β and p53γ regulate cellular response to modulation of alternative splicing pre-mRNA pathway by a small drug inhibitor. The development of novel drugs targeting alternative splicing process could be used as a novel therapeutic approach in human cancers. © 2014 Macmillan Publishers Limited All rights reserved.

Zyuzikov N.A.,Center for Oncology and Molecular Medicine | Coates P.J.,Center for Oncology and Molecular Medicine | Parry J.M.,Ninewells Hospital and Medical School | Lorimore S.A.,Center for Oncology and Molecular Medicine | Wright E.G.,Center for Oncology and Molecular Medicine
Radiation Research | Year: 2011

Exposure to high doses of ionizing radiation unequivocally produces adverse health effects including malignancy. At low doses the situation is much less clear, because effects are generally too small to be estimated directly by epidemiology, and extrapolation of risk and establishment of international rules and standards rely on the linear no-threshold (LNT) concept. Claims that low doses are more damaging than would be expected from LNT have been made on the basis of in vitro studies of nontargeted bystander effects and genomic instability, but relevant investigations of primary cells and tissues are limited. Here we show that after low-dose low-LET in vivo radiation exposures in the 0â€"100-mGy range of murine bone marrow there is no evidence of a bystander effect, assessed by p53 pathway signaling, nor is there any evidence for longer-term chromosomal instability in the bone marrow at doses below 1000  mGy. The data are not consistent with speculations based on in vitro nontargeted effects that low-dose X radiation is more damaging than would be expected from linear extrapolation. © 2011 by Radiation Research Society.

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