Finbarr Cotter | Queen Mary, University of London (original) (raw)

Papers by Finbarr Cotter

Research paper thumbnail of Molecular characterization of a myelodysplasia-associated chromosome 7 inversion

British Journal of Haematology, 2001

Chromosome 7 abnormalities are observed in a wide range of myeloid disorders, particularly myelod... more Chromosome 7 abnormalities are observed in a wide range of myeloid disorders, particularly myelodysplasia (MDS) and acute myeloid leukaemia (AML). Monosomy 7 and 7q deletions are the most frequent abnormalities, although translocations and inversions involving 7q also occur. The region 7q22±q34 may contain as many as four distinct minimal regions of deletion (MDRs), which are thought to contain one or more myeloid tumour-suppressor genes. We have defined previously the proximal breakpoint of a constitutional 7q22±q34 inversion, carried in a cell line derived from a member of a family with a history of MDS. A YAC clone spanning this breakpoint was identified. Both inversion breakpoints have now been cloned and q

Research paper thumbnail of Gene mapping by enzymatic amplification from flow-sorted chromosomes

Research paper thumbnail of Construction of cosmid libraries from flow-sorted human chromosomes 1, 6, 7, 11, 13, and 18 for reference library resources

Mammalian Genome, 1994

... Construction, arraying and high density screen-ing of large insert libraries of the human chr... more ... Construction, arraying and high density screen-ing of large insert libraries of the human chromosomes X and 21: their potential use as reference libraries. Proc. Natl. Acad. Sci. ... The reference library systemIsharing biological material and experimental data. Nature 367,489-481.

Research paper thumbnail of In vivo suppression of Bcl-XL expression facilitates chemotherapy-induced leukaemia cell death in a SCID/NOD-Hu model

Bcl-X L , a member of the Bcl-2-related antiapoptosis protein family, antagonizes a diverse range... more Bcl-X L , a member of the Bcl-2-related antiapoptosis protein family, antagonizes a diverse range of apoptosis-inducing stimuli by preventing mitochondrial permeability transition, release of apoptogenic factors including cytochrome C, and caspase activation. We have tested the hypothesis that the susceptibility of Bcl-X Lexpressing leukaemic cells to apoptosis induced by VP16 (etoposide) can be enhanced by pharmacological downregulation of Bcl-X L in vivo. Two subcutaneous xenograft models of B-cell leukaemia-employing SEMK-2 and BV173 cell lines were established in severe combined immunodeficient/non-obese diabetic mice followed by 14 d of continuous subcutaneous administration of Bcl-X L -specific second generation oligonucleotides ISIS 16009 or ISIS 15999. Tumours were disaggregated, enabling investigation of Bcl-X L expression and apoptosis susceptibility at single-cell resolution using cytofluorimetry. Marked sequence-specific reduction of Bcl-X L was associated with sequence-specific enhancement of VP16-induced mitochondrial permeability transition, caspase-3 activation and loss of membrane asymmetry. A negative correlation between Bcl-X L expression and apoptosis susceptibility was observed, together with a positive correlation with respect to a reduced redox state. Bcl-X L downregulation reduces the threshold for VP16-induced apoptosis by potentiating mitochondrial dysfunction and its sequelae, and therefore presents a novel therapeutic strategy for reversing chemoresistance.

Research paper thumbnail of Posttransplant cutaneous lymphoma

Journal of The American Academy of Dermatology, 1993

with systemic lupus erythematosus: importanceof null allelesof C4A and C4B in determiningdiseases... more with systemic lupus erythematosus: importanceof null allelesof C4A and C4B in determiningdiseasesusceptibility. Sr Moo J 1983;286:425-8. ] O. BriggsDC, Senaldi G, Isenberg DA, et a!. Influence of C4 null alleles on C4 activation in systemiclupuserythematosus. Ann Rheum Dis 1991;50:251-4. 11. Rynes RI. Inherited complement deficiency states and SLE. Clin Rheum Dis 1982;8:29-47. McGregor et at. 12. Gatenby PA, Barbosa JE, Lachmann Pf. Differences between C4A and C4B in the handling of immune complexes: the enhancementof CR 1 binding is more important than the inhibitionof immunoprecipitation. Clin Exp Im-munoI1990;79:158-63. 13. Awdeh ZL, Raum D, Yunis EJ, et a1. Extended HLAj complement allele haplotypes: evidence for Tit-like complex in man. Background: Posttransplant lymphoma is closely associated with Epstein-Barr virus (EBV) infection and appears to have a predilection for extranodal sites. We describe four cases of primary cutaneous posttransplant lymphoma.

Research paper thumbnail of BCL-2 antisense therapy in patients with non-Hodgkin lymphoma

The Lancet, 1997

Overexpression of BCL-2 is common in non-Hodgkin lymphoma and leads to resistance to programmed c... more Overexpression of BCL-2 is common in non-Hodgkin lymphoma and leads to resistance to programmed cell death (apoptosis) and promotes tumorigenesis. Antisense oligonucleotides targeted at the open reading frame of the BCL-2 mRNA cause a specific down-regulation of BCL-2 expression which leads to increased apoptosis. Lymphoma grown in laboratory animals responds to BCL-2 antisense oligonucleotides with few toxic effects. We report the first study of BCL-2 antisense therapy in human beings. A daily subcutaneous infusion of 18-base, fully phosporothioated antisense oligonucleotide was administered for 2 weeks to nine patients who had BCL-2-positive relapsed non-Hodgkin lymphoma. Toxicity was scored by the common toxicity criteria, and tumour response was assessed by computed tomography scan. Efficacy was also assessed by quantification of BCL-2 expression; BCL-2 protein levels were measured by flow cytometry in samples from patients. During the course of the study, the daily dose of BCL-2 antisense was increased incrementally from 4.6 mg/m2 to 73.6 mg/m2. No treatment-related toxic effects occurred, apart from local inflammation at the infusion site. In two patients, computed tomography scans showed a reduction in tumour size (one minor, one complete response). In two patients, the number of circulating lymphoma cells decreased during treatment. In four patients, serum concentrations of lactate dehydrogenase fell, and in two of these patients symptoms improved. We were able to measure BCL-2 levels by flow cytometry in the samples of five patients, two of whom had reduced levels of BCL-2 protein. In patients with relapsing non-Hodgkin lymphoma, BCL-2 antisense therapy led to an improvement in symptoms, objective biochemical and radiological evidence of tumour response, and down-regulation of the BCL-2 protein in some patients. Our findings are encouraging and warrant further investigations of BCL-2 antisense therapy in cancer treatment.

Research paper thumbnail of Gene expression changes in a zebrafish model of drug dependency suggest conservation of neuro-adaptation pathways

Journal of Experimental Biology, 2008

Addiction is a complex psychiatric disorder considered to be a disease of the brain&a... more Addiction is a complex psychiatric disorder considered to be a disease of the brain's natural reward reinforcement system. Repeated stimulation of the 'reward' pathway leads to adaptive changes in gene expression and synaptic organization that reinforce drug taking and underlie long-term changes in behaviour. The primitive nature of reward reinforcement pathways and the near universal ability of abused drugs to target the same system allow drug-associated reward and reinforcement to be studied in non-mammalian species. Zebrafish have proved to be a valuable model system for the study of vertebrate development and disease. Here we demonstrate that adult zebrafish show a dose-dependent acute conditioned place preference (CPP) reinforcement response to ethanol or nicotine. Repeated exposure of adult zebrafish to either nicotine or ethanol leads to a robust CPP response that persists following 3 weeks of abstinence and in the face of adverse stimuli, a behavioural indicator of the establishment of dependence. Microarray analysis using whole brain samples from drug-treated and control zebrafish identified 1362 genes that show a significant change in expression between control and treated individuals. Of these genes, 153 are common to both ethanol- and nicotine-treated animals. These genes include members of pathways and processes implicated in drug dependence in mammalian models, revealing conservation of neuro-adaptation pathways between zebrafish and mammals.

Research paper thumbnail of Role of DNA methylation in the suppression of Apaf-1 protein in human leukaemia

Oncogene, 2003

Apaf-1 protein deficiency occurs in human leukaemic blasts and confers resistance to cytochrome-c... more Apaf-1 protein deficiency occurs in human leukaemic blasts and confers resistance to cytochrome-c-dependent apoptosis. Demethylation treatment with 5-aza-2 0 -deoxycytidine (5aza2dc) increased the sensitivity of the K562 leukaemic cell line to UV light-induced apoptosis in association with increased Apaf-1 protein levels. There was no correlation between Apaf-1 protein expression and Apaf-1 mRNA levels after the demethylation treatment. Methylation-specific polymerase chain reaction was used to show that the methylation can occur within the Apaf-1 promoter region in leukaemic blasts. Apaf-1 DNA methylation was demonstrated in acute myeloid leukaemia, chronic myeloid leukaemia and acute lymphoid leukaemia, suggesting that it is not specific to a particular leukaemia subtype. Apaf-1 protein expression did not correlate with Apaf-1 mRNA levels in human leukaemic blasts. Some leukaemic cells expressed high levels of Apaf-1 mRNA but low levels of Apaf-1 protein. This study suggests that Apaf-1 DNA promoter methylation might contribute to the inactivation of Apaf-1 expression. However, Apaf-1 protein levels might also be controlled at post-transcription level.

Research paper thumbnail of Cloning of two candidate tumor suppressor genes within a 10 kb region on chromosome 13q14, frequently deleted in chronic lymphocytic leukemia

Research paper thumbnail of Molecular Genetics of Extranodal Marginal Zone (MALT-Type) B-Cell Lymphoma

Leukemia and Lymphoma, 1999

Mucosa-associated lymphoid tissue lymphoma is now classified as extranodal marginal zone B-cell l... more Mucosa-associated lymphoid tissue lymphoma is now classified as extranodal marginal zone B-cell lymphoma. We reviewed the current literature on the biological and genetic mechanisms that lead to the development and progression of this unusual lymphoma. Particular attention was given to the clinical and biological significance of the immunoglobulin genes rearrangement, that has been proposed and widely used both diagnostically and as a tool to monitor the response to antibiotic treatment.

Research paper thumbnail of Acquired mutations in GATA1 in neonates with Down's syndrome with transient myeloid disorder

The Lancet, 2003

Transient myeloid disorder is a unique self-regressing neoplasia specific to Down&amp... more Transient myeloid disorder is a unique self-regressing neoplasia specific to Down's syndrome. The transcription factor GATA1 is needed for normal growth and maturation of erythroid cells and megakaryocytes. Mutations in GATA1 have been reported in acute megakaryoblastic leukaemia in Down's syndrome. We aimed to investigate changes in GATA1 in patients with Down's syndrome and either transient myeloid disorder (n=10) or acute megakaryoblastic leukaemia (n=6). We recorded mutations eliminating exon 2 from GATA1 in all patients with transient myeloid disorder (age 0-24 days) and in all with acute megakaryoblastic leukaemia (age 14-38 months). The range of mutations did not differ between patients with each disorder. Patients with transient myeloid disorder with mutations in GATA1 can regress spontaneously to complete remission, and mutations do not necessarily predict later acute megakaryoblastic leukaemia.

Research paper thumbnail of Co-localisation of CCG repeats and chromosome deletion breakpoints in Jacobsen syndrome: evidence for a common mechanism of chromosome breakage

Human Molecular Genetics, 2000

Folate-sensitive fragile sites are associated with the expansion and hypermethylation of CCG-repe... more Folate-sensitive fragile sites are associated with the expansion and hypermethylation of CCG-repeats. The fragile site in 11q23.3, FRA11B, has been shown to cause chromosome deletions in vivo, its expression being associated with Jacobsen (11q-) syndrome. However, the majority of Jacobsen deletions are distal to FRA11B and are not related to its expression. To test the hypothesis that other unidentified fragile sites might be located in 11q23.3-24 and may cause these deletions, we have identified and characterised CCG-trinucleotide repeats within a 40 Mb YAC contig spanning distal chromosome 11q. Only eight CCG-repeats were identified within the entire YAC contig (not including FRA11B), six of which map to the region of 11q23.3-24 that includes Jacobsen deletions. We have previously collated the deletion mapping data of 24 Jacobsen patients with the physical map of chromosome 11q, and accurately localised six breakpoints to short intervals corresponding to individual YAC clones. We now show that in each of these cases, YAC clones found to contain a deletion breakpoint also contain a CCG-repeat. The improved analysis of one of these deletions, together with those of several new Jacobsen cases, further strengthens this association by localising five breakpoints to individual PAC clones containing CCG-repeats. These data provide strong evidence for the non-random clustering of chromosome deletion breakpoints with CCG-repeats, and suggests that they may play an important role in a common mechanism of chromosome breakage.

Research paper thumbnail of Confirmation of FWT1 as a Wilms’ tumour susceptibility gene and phenotypic characteristics of Wilms’ tumour attributable to FWT1

Human Genetics, 1998

A susceptibility gene for Wilms&a... more A susceptibility gene for Wilms' tumour (WT), designated FWT1, was previously mapped to chromosome 17q12-q21 by linkage analysis of a single family. We now confirm the existence of this gene by analysis of additional cases in the original family (3-point LOD score=5.69), and by detecting strong evidence of linkage to this region in an unrelated pedigree with seven cases of WT (3-point LOD score=2.56). Analysis of 11 smaller WT families confirms that there is genetic heterogeneity in familial WT, as three families exhibit strong evidence against linkage to FWT1. One of these was subsequently found to have a predisposing WT1 mutation. However, the other two families show evidence against both FWT1 and WT1, suggesting that at least one further familial WT gene exists. Analysis of the phenotype of 16 WT cases from the families linked to FWT1 demonstrates that they present at a significantly older age and a significantly later stage than both sporadic WT and the six cases from two families unlinked to either FWT1 or WT1. The results confirm the role of FWT1 in susceptibility to WT, provide strong evidence for genetic heterogeneity in familial WT and suggest there are phenotypic differences between familial WT due to FWT1, familial WT due to other genes and non-familial WT.

Research paper thumbnail of A Novel Phenotype of Glycogen Storage Disease Presenting as Gastrointestinal Neuromuscular Disease

Scientia Horticulturae, 2011

Research paper thumbnail of Antisense Bcl–2 Oligonucleotide Uptake in Human Transitional Cell Carcinoma

European Urology, 2001

Antisense oligonucleotides (AO) downregulate Bcl-2 protein expression in various tumours if good ... more Antisense oligonucleotides (AO) downregulate Bcl-2 protein expression in various tumours if good target cell uptake is achieved. In this study, uptake of FITC labelled AO (FITC-AO) directed at Bcl-2 was examined in: (1) the RT4 bladder tumour cell line; (2) normal pig urothelium, and (3) human superficial bladder tumours. In the RT4 cell line, uptake of FITC-AO, FITC-scrambled and FITC-sense oligonucleotides were quantified by flow cytometry at 4-hour intervals over 24 h. Uptake of FITC-AO was assessed in normal pig urothelium by flow cytometry after FITC-AO was infused for 1 h. Uptake of FITC AO was assessed in samples from 14 human superficial bladder tumours which were maintained in an ex vivo model. In samples from 6 tumours, uptake at 4 h was assessed using fluorescence microscopy. In samples from 8 separate tumours uptake every 4 h within the first 24-hour incubation period was assessed by flow cytometry. In the RT4 cell line the FITC-AO, FITC-scrambled and FITC-sense oligonucleotide uptake was similar. Disaggregated cells from the normal urothelium of the 3 pigs exhibited 33, 46 and 51% of cells staining positively for FITC-AO as determined by flow cytometry. All 6 tumour samples had detectable intracellular FITC-AO by fluorescence microscopy at 4 h. In the 8 tumours examined over the 24-hour incubation period, there was a range of percentages of positively staining cells. However, most tumours had a monotonic increase in intracellular fluorescence intensity that plateaued 16 h post-infusion. Antisense Bcl-2 oligonucleotides were readily taken up by superficial bladder cancer cells but the heterogeneous uptake in tumour samples needs to be considered when assessing the bioavailability of these drugs.

Research paper thumbnail of Trinucleotide repeat dynamic mutation identifying susceptibility in familial and sporadic chronic lymphocytic leukaemia

British Journal of Haematology, 2007

Chronic lymphocytic leukaemia (CLL) has a strong hereditary component, but an understanding of pr... more Chronic lymphocytic leukaemia (CLL) has a strong hereditary component, but an understanding of predisposition genes is poor. Anticipation with familial CLL has been reported, although the molecular mechanism is unknown. Expansion of trinucleotide repeat sequences underlies anticipation observed in neurodegenerative disease. A polymerase chain reaction-based assay was used to analyse the stability of ten CCG-and CAG-trinucleotide repeat tracts in 18 CLL families and 140 patients with the sporadic form of the disease. The study suggests that anticipation, if it occurs in CLL, is not linked to CCG-and CAG-repeat expansion, however, variation in repeat length at certain loci (FRA16A) may permit identification of susceptible family members. In addition, polymorphisms with prognostic significance were identified. These were high length (but not expanded) repeats at FRA11B (P ¼ 0AE01), ATXN1 (P ¼ 0AE032) and ATXN3 (P ¼ 0AE022), all associated with poor risk disease.

Research paper thumbnail of Molecular characterization of a myelodysplasia-associated chromosome 7 inversion

British Journal of Haematology, 2001

Chromosome 7 abnormalities are observed in a wide range of myeloid disorders, particularly myelod... more Chromosome 7 abnormalities are observed in a wide range of myeloid disorders, particularly myelodysplasia (MDS) and acute myeloid leukaemia (AML). Monosomy 7 and 7q deletions are the most frequent abnormalities, although translocations and inversions involving 7q also occur. The region 7q22±q34 may contain as many as four distinct minimal regions of deletion (MDRs), which are thought to contain one or more myeloid tumour-suppressor genes. We have defined previously the proximal breakpoint of a constitutional 7q22±q34 inversion, carried in a cell line derived from a member of a family with a history of MDS. A YAC clone spanning this breakpoint was identified. Both inversion breakpoints have now been cloned and q

Research paper thumbnail of Genomic and expression profiling identifies the B-cell associated tyrosine kinase Syk as a possible therapeutic target in mantle cell lymphoma

British Journal of Haematology, 2006

Among B-cell lymphomas mantle cell lymphoma (MCL) has the worst prognosis. By using a combination... more Among B-cell lymphomas mantle cell lymphoma (MCL) has the worst prognosis. By using a combination of genomic and expression profiling (Affymetrix GeneChip Mapping 10k Xba131 and U133 set), we analysed 26 MCL samples to identify genes relevant to MCL pathogenesis and that could represent new therapeutic targets. Recurrent genomic deletions and gains were detected. Genes were identified as overexpressed in regions of DNA gain on 3q, 6p, 8q, 9q, 16p and 18q, including the cancer genes BCL2 and MYC. Among the transcripts with high correlation between DNA and RNA, we identified SYK, a tyrosine kinase involved in B-cell receptor signalling. SYK was amplified at DNA level, as validated by fluorescence in situ hybridisation (FISH) analysis, and overexpressed at both RNA and protein levels in the JeKo-1 cell line. Low-level amplification, with protein overexpression of Syk was demonstrated by FISH in a small subset of clinical samples. After treatment with low doses of the Syk inhibitor piceatannol, cell proliferation arrest and apoptosis were induced in the cell line overexpressing Syk, while cells expressing low levels of Syk were much less sensitive. A combination of genomic and expression profiling suggested Syk inhibition as a new therapeutic strategy to be explored in lymphomas.

Research paper thumbnail of In vivo suppression of Bcl-XL expression facilitates chemotherapy-induced leukaemia cell death in a SCID/NOD-Hu model

British Journal of Haematology, 2001

Bcl-X L , a member of the Bcl-2-related antiapoptosis protein family, antagonizes a diverse range... more Bcl-X L , a member of the Bcl-2-related antiapoptosis protein family, antagonizes a diverse range of apoptosis-inducing stimuli by preventing mitochondrial permeability transition, release of apoptogenic factors including cytochrome C, and caspase activation. We have tested the hypothesis that the susceptibility of Bcl-X Lexpressing leukaemic cells to apoptosis induced by VP16 (etoposide) can be enhanced by pharmacological downregulation of Bcl-X L in vivo. Two subcutaneous xenograft models of B-cell leukaemia-employing SEMK-2 and BV173 cell lines were established in severe combined immunodeficient/non-obese diabetic mice followed by 14 d of continuous subcutaneous administration of Bcl-X L -specific second generation oligonucleotides ISIS 16009 or ISIS 15999. Tumours were disaggregated, enabling investigation of Bcl-X L expression and apoptosis susceptibility at single-cell resolution using cytofluorimetry. Marked sequence-specific reduction of Bcl-X L was associated with sequence-specific enhancement of VP16-induced mitochondrial permeability transition, caspase-3 activation and loss of membrane asymmetry. A negative correlation between Bcl-X L expression and apoptosis susceptibility was observed, together with a positive correlation with respect to a reduced redox state. Bcl-X L downregulation reduces the threshold for VP16-induced apoptosis by potentiating mitochondrial dysfunction and its sequelae, and therefore presents a novel therapeutic strategy for reversing chemoresistance.

Research paper thumbnail of Molecular basis of mantle cell lymphoma

British Journal of Haematology, 2004

Research paper thumbnail of Molecular characterization of a myelodysplasia-associated chromosome 7 inversion

British Journal of Haematology, 2001

Chromosome 7 abnormalities are observed in a wide range of myeloid disorders, particularly myelod... more Chromosome 7 abnormalities are observed in a wide range of myeloid disorders, particularly myelodysplasia (MDS) and acute myeloid leukaemia (AML). Monosomy 7 and 7q deletions are the most frequent abnormalities, although translocations and inversions involving 7q also occur. The region 7q22±q34 may contain as many as four distinct minimal regions of deletion (MDRs), which are thought to contain one or more myeloid tumour-suppressor genes. We have defined previously the proximal breakpoint of a constitutional 7q22±q34 inversion, carried in a cell line derived from a member of a family with a history of MDS. A YAC clone spanning this breakpoint was identified. Both inversion breakpoints have now been cloned and q

Research paper thumbnail of Gene mapping by enzymatic amplification from flow-sorted chromosomes

Research paper thumbnail of Construction of cosmid libraries from flow-sorted human chromosomes 1, 6, 7, 11, 13, and 18 for reference library resources

Mammalian Genome, 1994

... Construction, arraying and high density screen-ing of large insert libraries of the human chr... more ... Construction, arraying and high density screen-ing of large insert libraries of the human chromosomes X and 21: their potential use as reference libraries. Proc. Natl. Acad. Sci. ... The reference library systemIsharing biological material and experimental data. Nature 367,489-481.

Research paper thumbnail of In vivo suppression of Bcl-XL expression facilitates chemotherapy-induced leukaemia cell death in a SCID/NOD-Hu model

Bcl-X L , a member of the Bcl-2-related antiapoptosis protein family, antagonizes a diverse range... more Bcl-X L , a member of the Bcl-2-related antiapoptosis protein family, antagonizes a diverse range of apoptosis-inducing stimuli by preventing mitochondrial permeability transition, release of apoptogenic factors including cytochrome C, and caspase activation. We have tested the hypothesis that the susceptibility of Bcl-X Lexpressing leukaemic cells to apoptosis induced by VP16 (etoposide) can be enhanced by pharmacological downregulation of Bcl-X L in vivo. Two subcutaneous xenograft models of B-cell leukaemia-employing SEMK-2 and BV173 cell lines were established in severe combined immunodeficient/non-obese diabetic mice followed by 14 d of continuous subcutaneous administration of Bcl-X L -specific second generation oligonucleotides ISIS 16009 or ISIS 15999. Tumours were disaggregated, enabling investigation of Bcl-X L expression and apoptosis susceptibility at single-cell resolution using cytofluorimetry. Marked sequence-specific reduction of Bcl-X L was associated with sequence-specific enhancement of VP16-induced mitochondrial permeability transition, caspase-3 activation and loss of membrane asymmetry. A negative correlation between Bcl-X L expression and apoptosis susceptibility was observed, together with a positive correlation with respect to a reduced redox state. Bcl-X L downregulation reduces the threshold for VP16-induced apoptosis by potentiating mitochondrial dysfunction and its sequelae, and therefore presents a novel therapeutic strategy for reversing chemoresistance.

Research paper thumbnail of Posttransplant cutaneous lymphoma

Journal of The American Academy of Dermatology, 1993

with systemic lupus erythematosus: importanceof null allelesof C4A and C4B in determiningdiseases... more with systemic lupus erythematosus: importanceof null allelesof C4A and C4B in determiningdiseasesusceptibility. Sr Moo J 1983;286:425-8. ] O. BriggsDC, Senaldi G, Isenberg DA, et a!. Influence of C4 null alleles on C4 activation in systemiclupuserythematosus. Ann Rheum Dis 1991;50:251-4. 11. Rynes RI. Inherited complement deficiency states and SLE. Clin Rheum Dis 1982;8:29-47. McGregor et at. 12. Gatenby PA, Barbosa JE, Lachmann Pf. Differences between C4A and C4B in the handling of immune complexes: the enhancementof CR 1 binding is more important than the inhibitionof immunoprecipitation. Clin Exp Im-munoI1990;79:158-63. 13. Awdeh ZL, Raum D, Yunis EJ, et a1. Extended HLAj complement allele haplotypes: evidence for Tit-like complex in man. Background: Posttransplant lymphoma is closely associated with Epstein-Barr virus (EBV) infection and appears to have a predilection for extranodal sites. We describe four cases of primary cutaneous posttransplant lymphoma.

Research paper thumbnail of BCL-2 antisense therapy in patients with non-Hodgkin lymphoma

The Lancet, 1997

Overexpression of BCL-2 is common in non-Hodgkin lymphoma and leads to resistance to programmed c... more Overexpression of BCL-2 is common in non-Hodgkin lymphoma and leads to resistance to programmed cell death (apoptosis) and promotes tumorigenesis. Antisense oligonucleotides targeted at the open reading frame of the BCL-2 mRNA cause a specific down-regulation of BCL-2 expression which leads to increased apoptosis. Lymphoma grown in laboratory animals responds to BCL-2 antisense oligonucleotides with few toxic effects. We report the first study of BCL-2 antisense therapy in human beings. A daily subcutaneous infusion of 18-base, fully phosporothioated antisense oligonucleotide was administered for 2 weeks to nine patients who had BCL-2-positive relapsed non-Hodgkin lymphoma. Toxicity was scored by the common toxicity criteria, and tumour response was assessed by computed tomography scan. Efficacy was also assessed by quantification of BCL-2 expression; BCL-2 protein levels were measured by flow cytometry in samples from patients. During the course of the study, the daily dose of BCL-2 antisense was increased incrementally from 4.6 mg/m2 to 73.6 mg/m2. No treatment-related toxic effects occurred, apart from local inflammation at the infusion site. In two patients, computed tomography scans showed a reduction in tumour size (one minor, one complete response). In two patients, the number of circulating lymphoma cells decreased during treatment. In four patients, serum concentrations of lactate dehydrogenase fell, and in two of these patients symptoms improved. We were able to measure BCL-2 levels by flow cytometry in the samples of five patients, two of whom had reduced levels of BCL-2 protein. In patients with relapsing non-Hodgkin lymphoma, BCL-2 antisense therapy led to an improvement in symptoms, objective biochemical and radiological evidence of tumour response, and down-regulation of the BCL-2 protein in some patients. Our findings are encouraging and warrant further investigations of BCL-2 antisense therapy in cancer treatment.

Research paper thumbnail of Gene expression changes in a zebrafish model of drug dependency suggest conservation of neuro-adaptation pathways

Journal of Experimental Biology, 2008

Addiction is a complex psychiatric disorder considered to be a disease of the brain&a... more Addiction is a complex psychiatric disorder considered to be a disease of the brain's natural reward reinforcement system. Repeated stimulation of the 'reward' pathway leads to adaptive changes in gene expression and synaptic organization that reinforce drug taking and underlie long-term changes in behaviour. The primitive nature of reward reinforcement pathways and the near universal ability of abused drugs to target the same system allow drug-associated reward and reinforcement to be studied in non-mammalian species. Zebrafish have proved to be a valuable model system for the study of vertebrate development and disease. Here we demonstrate that adult zebrafish show a dose-dependent acute conditioned place preference (CPP) reinforcement response to ethanol or nicotine. Repeated exposure of adult zebrafish to either nicotine or ethanol leads to a robust CPP response that persists following 3 weeks of abstinence and in the face of adverse stimuli, a behavioural indicator of the establishment of dependence. Microarray analysis using whole brain samples from drug-treated and control zebrafish identified 1362 genes that show a significant change in expression between control and treated individuals. Of these genes, 153 are common to both ethanol- and nicotine-treated animals. These genes include members of pathways and processes implicated in drug dependence in mammalian models, revealing conservation of neuro-adaptation pathways between zebrafish and mammals.

Research paper thumbnail of Role of DNA methylation in the suppression of Apaf-1 protein in human leukaemia

Oncogene, 2003

Apaf-1 protein deficiency occurs in human leukaemic blasts and confers resistance to cytochrome-c... more Apaf-1 protein deficiency occurs in human leukaemic blasts and confers resistance to cytochrome-c-dependent apoptosis. Demethylation treatment with 5-aza-2 0 -deoxycytidine (5aza2dc) increased the sensitivity of the K562 leukaemic cell line to UV light-induced apoptosis in association with increased Apaf-1 protein levels. There was no correlation between Apaf-1 protein expression and Apaf-1 mRNA levels after the demethylation treatment. Methylation-specific polymerase chain reaction was used to show that the methylation can occur within the Apaf-1 promoter region in leukaemic blasts. Apaf-1 DNA methylation was demonstrated in acute myeloid leukaemia, chronic myeloid leukaemia and acute lymphoid leukaemia, suggesting that it is not specific to a particular leukaemia subtype. Apaf-1 protein expression did not correlate with Apaf-1 mRNA levels in human leukaemic blasts. Some leukaemic cells expressed high levels of Apaf-1 mRNA but low levels of Apaf-1 protein. This study suggests that Apaf-1 DNA promoter methylation might contribute to the inactivation of Apaf-1 expression. However, Apaf-1 protein levels might also be controlled at post-transcription level.

Research paper thumbnail of Cloning of two candidate tumor suppressor genes within a 10 kb region on chromosome 13q14, frequently deleted in chronic lymphocytic leukemia

Research paper thumbnail of Molecular Genetics of Extranodal Marginal Zone (MALT-Type) B-Cell Lymphoma

Leukemia and Lymphoma, 1999

Mucosa-associated lymphoid tissue lymphoma is now classified as extranodal marginal zone B-cell l... more Mucosa-associated lymphoid tissue lymphoma is now classified as extranodal marginal zone B-cell lymphoma. We reviewed the current literature on the biological and genetic mechanisms that lead to the development and progression of this unusual lymphoma. Particular attention was given to the clinical and biological significance of the immunoglobulin genes rearrangement, that has been proposed and widely used both diagnostically and as a tool to monitor the response to antibiotic treatment.

Research paper thumbnail of Acquired mutations in GATA1 in neonates with Down's syndrome with transient myeloid disorder

The Lancet, 2003

Transient myeloid disorder is a unique self-regressing neoplasia specific to Down&amp... more Transient myeloid disorder is a unique self-regressing neoplasia specific to Down's syndrome. The transcription factor GATA1 is needed for normal growth and maturation of erythroid cells and megakaryocytes. Mutations in GATA1 have been reported in acute megakaryoblastic leukaemia in Down's syndrome. We aimed to investigate changes in GATA1 in patients with Down's syndrome and either transient myeloid disorder (n=10) or acute megakaryoblastic leukaemia (n=6). We recorded mutations eliminating exon 2 from GATA1 in all patients with transient myeloid disorder (age 0-24 days) and in all with acute megakaryoblastic leukaemia (age 14-38 months). The range of mutations did not differ between patients with each disorder. Patients with transient myeloid disorder with mutations in GATA1 can regress spontaneously to complete remission, and mutations do not necessarily predict later acute megakaryoblastic leukaemia.

Research paper thumbnail of Co-localisation of CCG repeats and chromosome deletion breakpoints in Jacobsen syndrome: evidence for a common mechanism of chromosome breakage

Human Molecular Genetics, 2000

Folate-sensitive fragile sites are associated with the expansion and hypermethylation of CCG-repe... more Folate-sensitive fragile sites are associated with the expansion and hypermethylation of CCG-repeats. The fragile site in 11q23.3, FRA11B, has been shown to cause chromosome deletions in vivo, its expression being associated with Jacobsen (11q-) syndrome. However, the majority of Jacobsen deletions are distal to FRA11B and are not related to its expression. To test the hypothesis that other unidentified fragile sites might be located in 11q23.3-24 and may cause these deletions, we have identified and characterised CCG-trinucleotide repeats within a 40 Mb YAC contig spanning distal chromosome 11q. Only eight CCG-repeats were identified within the entire YAC contig (not including FRA11B), six of which map to the region of 11q23.3-24 that includes Jacobsen deletions. We have previously collated the deletion mapping data of 24 Jacobsen patients with the physical map of chromosome 11q, and accurately localised six breakpoints to short intervals corresponding to individual YAC clones. We now show that in each of these cases, YAC clones found to contain a deletion breakpoint also contain a CCG-repeat. The improved analysis of one of these deletions, together with those of several new Jacobsen cases, further strengthens this association by localising five breakpoints to individual PAC clones containing CCG-repeats. These data provide strong evidence for the non-random clustering of chromosome deletion breakpoints with CCG-repeats, and suggests that they may play an important role in a common mechanism of chromosome breakage.

Research paper thumbnail of Confirmation of FWT1 as a Wilms’ tumour susceptibility gene and phenotypic characteristics of Wilms’ tumour attributable to FWT1

Human Genetics, 1998

A susceptibility gene for Wilms&a... more A susceptibility gene for Wilms' tumour (WT), designated FWT1, was previously mapped to chromosome 17q12-q21 by linkage analysis of a single family. We now confirm the existence of this gene by analysis of additional cases in the original family (3-point LOD score=5.69), and by detecting strong evidence of linkage to this region in an unrelated pedigree with seven cases of WT (3-point LOD score=2.56). Analysis of 11 smaller WT families confirms that there is genetic heterogeneity in familial WT, as three families exhibit strong evidence against linkage to FWT1. One of these was subsequently found to have a predisposing WT1 mutation. However, the other two families show evidence against both FWT1 and WT1, suggesting that at least one further familial WT gene exists. Analysis of the phenotype of 16 WT cases from the families linked to FWT1 demonstrates that they present at a significantly older age and a significantly later stage than both sporadic WT and the six cases from two families unlinked to either FWT1 or WT1. The results confirm the role of FWT1 in susceptibility to WT, provide strong evidence for genetic heterogeneity in familial WT and suggest there are phenotypic differences between familial WT due to FWT1, familial WT due to other genes and non-familial WT.

Research paper thumbnail of A Novel Phenotype of Glycogen Storage Disease Presenting as Gastrointestinal Neuromuscular Disease

Scientia Horticulturae, 2011

Research paper thumbnail of Antisense Bcl–2 Oligonucleotide Uptake in Human Transitional Cell Carcinoma

European Urology, 2001

Antisense oligonucleotides (AO) downregulate Bcl-2 protein expression in various tumours if good ... more Antisense oligonucleotides (AO) downregulate Bcl-2 protein expression in various tumours if good target cell uptake is achieved. In this study, uptake of FITC labelled AO (FITC-AO) directed at Bcl-2 was examined in: (1) the RT4 bladder tumour cell line; (2) normal pig urothelium, and (3) human superficial bladder tumours. In the RT4 cell line, uptake of FITC-AO, FITC-scrambled and FITC-sense oligonucleotides were quantified by flow cytometry at 4-hour intervals over 24 h. Uptake of FITC-AO was assessed in normal pig urothelium by flow cytometry after FITC-AO was infused for 1 h. Uptake of FITC AO was assessed in samples from 14 human superficial bladder tumours which were maintained in an ex vivo model. In samples from 6 tumours, uptake at 4 h was assessed using fluorescence microscopy. In samples from 8 separate tumours uptake every 4 h within the first 24-hour incubation period was assessed by flow cytometry. In the RT4 cell line the FITC-AO, FITC-scrambled and FITC-sense oligonucleotide uptake was similar. Disaggregated cells from the normal urothelium of the 3 pigs exhibited 33, 46 and 51% of cells staining positively for FITC-AO as determined by flow cytometry. All 6 tumour samples had detectable intracellular FITC-AO by fluorescence microscopy at 4 h. In the 8 tumours examined over the 24-hour incubation period, there was a range of percentages of positively staining cells. However, most tumours had a monotonic increase in intracellular fluorescence intensity that plateaued 16 h post-infusion. Antisense Bcl-2 oligonucleotides were readily taken up by superficial bladder cancer cells but the heterogeneous uptake in tumour samples needs to be considered when assessing the bioavailability of these drugs.

Research paper thumbnail of Trinucleotide repeat dynamic mutation identifying susceptibility in familial and sporadic chronic lymphocytic leukaemia

British Journal of Haematology, 2007

Chronic lymphocytic leukaemia (CLL) has a strong hereditary component, but an understanding of pr... more Chronic lymphocytic leukaemia (CLL) has a strong hereditary component, but an understanding of predisposition genes is poor. Anticipation with familial CLL has been reported, although the molecular mechanism is unknown. Expansion of trinucleotide repeat sequences underlies anticipation observed in neurodegenerative disease. A polymerase chain reaction-based assay was used to analyse the stability of ten CCG-and CAG-trinucleotide repeat tracts in 18 CLL families and 140 patients with the sporadic form of the disease. The study suggests that anticipation, if it occurs in CLL, is not linked to CCG-and CAG-repeat expansion, however, variation in repeat length at certain loci (FRA16A) may permit identification of susceptible family members. In addition, polymorphisms with prognostic significance were identified. These were high length (but not expanded) repeats at FRA11B (P ¼ 0AE01), ATXN1 (P ¼ 0AE032) and ATXN3 (P ¼ 0AE022), all associated with poor risk disease.

Research paper thumbnail of Molecular characterization of a myelodysplasia-associated chromosome 7 inversion

British Journal of Haematology, 2001

Chromosome 7 abnormalities are observed in a wide range of myeloid disorders, particularly myelod... more Chromosome 7 abnormalities are observed in a wide range of myeloid disorders, particularly myelodysplasia (MDS) and acute myeloid leukaemia (AML). Monosomy 7 and 7q deletions are the most frequent abnormalities, although translocations and inversions involving 7q also occur. The region 7q22±q34 may contain as many as four distinct minimal regions of deletion (MDRs), which are thought to contain one or more myeloid tumour-suppressor genes. We have defined previously the proximal breakpoint of a constitutional 7q22±q34 inversion, carried in a cell line derived from a member of a family with a history of MDS. A YAC clone spanning this breakpoint was identified. Both inversion breakpoints have now been cloned and q

Research paper thumbnail of Genomic and expression profiling identifies the B-cell associated tyrosine kinase Syk as a possible therapeutic target in mantle cell lymphoma

British Journal of Haematology, 2006

Among B-cell lymphomas mantle cell lymphoma (MCL) has the worst prognosis. By using a combination... more Among B-cell lymphomas mantle cell lymphoma (MCL) has the worst prognosis. By using a combination of genomic and expression profiling (Affymetrix GeneChip Mapping 10k Xba131 and U133 set), we analysed 26 MCL samples to identify genes relevant to MCL pathogenesis and that could represent new therapeutic targets. Recurrent genomic deletions and gains were detected. Genes were identified as overexpressed in regions of DNA gain on 3q, 6p, 8q, 9q, 16p and 18q, including the cancer genes BCL2 and MYC. Among the transcripts with high correlation between DNA and RNA, we identified SYK, a tyrosine kinase involved in B-cell receptor signalling. SYK was amplified at DNA level, as validated by fluorescence in situ hybridisation (FISH) analysis, and overexpressed at both RNA and protein levels in the JeKo-1 cell line. Low-level amplification, with protein overexpression of Syk was demonstrated by FISH in a small subset of clinical samples. After treatment with low doses of the Syk inhibitor piceatannol, cell proliferation arrest and apoptosis were induced in the cell line overexpressing Syk, while cells expressing low levels of Syk were much less sensitive. A combination of genomic and expression profiling suggested Syk inhibition as a new therapeutic strategy to be explored in lymphomas.

Research paper thumbnail of In vivo suppression of Bcl-XL expression facilitates chemotherapy-induced leukaemia cell death in a SCID/NOD-Hu model

British Journal of Haematology, 2001

Bcl-X L , a member of the Bcl-2-related antiapoptosis protein family, antagonizes a diverse range... more Bcl-X L , a member of the Bcl-2-related antiapoptosis protein family, antagonizes a diverse range of apoptosis-inducing stimuli by preventing mitochondrial permeability transition, release of apoptogenic factors including cytochrome C, and caspase activation. We have tested the hypothesis that the susceptibility of Bcl-X Lexpressing leukaemic cells to apoptosis induced by VP16 (etoposide) can be enhanced by pharmacological downregulation of Bcl-X L in vivo. Two subcutaneous xenograft models of B-cell leukaemia-employing SEMK-2 and BV173 cell lines were established in severe combined immunodeficient/non-obese diabetic mice followed by 14 d of continuous subcutaneous administration of Bcl-X L -specific second generation oligonucleotides ISIS 16009 or ISIS 15999. Tumours were disaggregated, enabling investigation of Bcl-X L expression and apoptosis susceptibility at single-cell resolution using cytofluorimetry. Marked sequence-specific reduction of Bcl-X L was associated with sequence-specific enhancement of VP16-induced mitochondrial permeability transition, caspase-3 activation and loss of membrane asymmetry. A negative correlation between Bcl-X L expression and apoptosis susceptibility was observed, together with a positive correlation with respect to a reduced redox state. Bcl-X L downregulation reduces the threshold for VP16-induced apoptosis by potentiating mitochondrial dysfunction and its sequelae, and therefore presents a novel therapeutic strategy for reversing chemoresistance.

Research paper thumbnail of Molecular basis of mantle cell lymphoma

British Journal of Haematology, 2004