• Antimigratory and antimetastatic effect of heparin-derived 4-18 unit oligosaccharides in a preclinical human melanoma metastasis model.

      Kenessey, István; Simon, Erika; Futosi, Krisztina; Bereczky, Bíborka; Kiss, Andrea; Erdödi, Ferenc; Gallagher, John T; Tímár, József; Tóvári, József; Department of Tumor Progression, National Institute of Oncology, Budapest, Hungary. (2009-12)
      Heparin and its derivatives have been shown to inhibit angiogenesis and metastasis formation. Accordingly, we investigated the effect of heparin fragments containing 4 to 22 monomers on human melanoma cell proliferation, migration and invasion in vitro as well as on the in vivo metastatic potential in a SCID mouse model. Only oligosaccharide dp18 had significant inhibitory effect on cell proliferation. In contrast, cell migration was inhibited by all oligosaccharides studied except dp8 and dp22. Anti-CD44v3 antibody stimulated cell migration and invasion, and this effect could be attenuated by oligosaccharides dp4 and dp18. These fragments also inhibited the catalytic activity of myosin light chain phosphatase as well. Moreover, oligosaccharides dp4 and dp18 reduced the number of lung colonies formed in SCID mice intravenously injected with human melanoma cells, while dp22 proved to be ineffective in this respect. These studies revealed that fragments of heparin have an antimigratory and antimetastatic potential. These fragments lack the haemostatic effect of heparin, suggesting that they are potential specific antimetastatic agents in anticancer therapy.
    • Monoclonal antibodies directed to CD20 and HLA-DR can elicit homotypic adhesion followed by lysosome-mediated cell death in human lymphoma and leukemia cells.

      Ivanov, Andrei; Beers, Stephen A; Walshe, Claire A; Honeychurch, Jamie; Alduaij, Waleed; Cox, Kerry L; Potter, Kathleen N; Murray, Stephen M; Chan, Claude H T; Klymenko, Tetyana; et al. (2009-08)
      mAbs are becoming increasingly utilized in the treatment of lymphoid disorders. Although Fc-FcgammaR interactions are thought to account for much of their therapeutic effect, this does not explain why certain mAb specificities are more potent than others. An additional effector mechanism underlying the action of some mAbs is the direct induction of cell death. Previously, we demonstrated that certain CD20-specific mAbs (which we termed type II mAbs) evoke a nonapoptotic mode of cell death that appears to be linked with the induction of homotypic adhesion. Here, we reveal that peripheral relocalization of actin is critical for the adhesion and cell death induced by both the type II CD20-specific mAb tositumomab and an HLA-DR-specific mAb in both human lymphoma cell lines and primary chronic lymphocytic leukemia cells. The cell death elicited was rapid, nonapoptotic, nonautophagic, and dependent on the integrity of plasma membrane cholesterol and activation of the V-type ATPase. This cytoplasmic cell death involved lysosomes, which swelled and then dispersed their contents, including cathepsin B, into the cytoplasm and surrounding environment. The resulting loss of plasma membrane integrity occurred independently of caspases and was not controlled by Bcl-2. These experiments provide what we believe to be new insights into the mechanisms by which 2 clinically relevant mAbs elicit cell death and show that this homotypic adhesion-related cell death occurs through a lysosome-dependent pathway.
    • Spectral discrimination of live prostate and bladder cancer cell lines using Raman optical tweezers.

      Harvey, Tim J; Faria, Elsa Correia; Henderson, Alex; Gazi, Ehsan; Ward, Andrew D; Clarke, Noel W; Brown, Michael D; Snook, Richard D; Gardner, Peter; University of Manchester, School of Chemical Engineering and Analytical Science, Manchester Interdisciplinary Biocentre, 131 Princess Street, Manchester, Manchester M1 7DN, United Kingdom. (2009-07-16)
      An investigation into the use of Raman optical tweezers to study urological cell lines is reported, with the ultimate aim of determining the presence of malignant CaP cells in urine and peripheral fluids. To this end, we trapped and analyzed live CaP cells (PC-3) and bladder cells (MGH-U1), because both prostate and bladder cells are likely to be present in urine. The laser excitation wavelength of 514.5 nm was used, with Raman light collected both in back- and forward-scattering geometric configurations. For the backscattering configuration the same laser was used for trapping and excitation, while for forward scattering a 1064 nm laser provided the trapping beam. Analysis of cell-diameter distributions for cells analyzed suggested normal distribution of cell sizes, indicating an unbiased cell-selection criterion. Principal components analysis afforded discrimination of MGH-U1 and PC-3 spectra collected in either configuration, demonstrating that it is possible to trap, analyze, and differentiate PC-3 from MGH-U1 cells using a 514.5 nm laser. By loading plot analysis, possible biomolecules responsible for discrimination in both configurations were determined. Finally, the effect of cell size on discrimination was investigated, with results indicating that separation is based predominantly on cell type rather than cell size.
    • Developing a CTCAEs patient questionnaire for late toxicity after head and neck radiotherapy.

      Ho, Kean F; Farnell, Damian J J; Routledge, Jacqueline A; Burns, Meriel P; Sykes, Andrew J; Slevin, Nicholas J; Davidson, Susan E; Academic Radiation Oncology, University of Manchester, The Christie NHS Foundation Trust, Wilmslow Road, Manchester M20 4BX, United Kingdom. (2009-05-06)
      PURPOSE: Patient-based reporting of symptoms is increasingly important in providing treatment toxicity information. However, observer-based scoring systems such as the CTCAEs which incorporate the LENT-SOMA scales are not adapted for patient-based reporting. We aim to (1) report the late toxicity in patients following head and neck radiotherapy using a LENT-SOMA patient-based questionnaire, (2) describe how the responses help to improve the questionnaire and (3) adapt the questionnaire for patient reporting using CTCAEs. METHODS: A 31-item LENT-SOMA patient questionnaire was administered prospectively to 220 patients pre-treatment and at eight time periods post-radical head and neck radiotherapy over 3 years. Exploratory factor analysis was carried out and questionnaire reliability was evaluated using Cronbach's alpha coefficient. RESULTS: At 3-years follow-up, grade 3/4 toxicity was recorded for xerostomia (44%), hoarseness (14.3%), altered taste (6.1%) and oropharyngeal pain (1.9%). Factor analysis indicated that questionnaire division according to anatomical sub-site was reasonable. Cronbach's alpha was 0.851 (95% CI: 0.820-0.883) indicating high reliability. Good compliance was obtained with all questions except for the 'weight loss' item. A satisfaction survey showed that the questionnaire was clear and concise. Teeth and mandible sections have been removed. Dietary change due to xerostomia has been incorporated in line with CTCAEs. LENT-SOMA scoring of analgesic needs and dysphagia not described in CTCAEs were found useful and have been retained. CONCLUSIONS: The questionnaire has enabled reporting of late toxicity and the responses have enabled refinement of the questionnaire. It is reliable, feasible and has been validated for patient-based collection of CTCAEs late toxicity data.
    • Quantitative analysis of biomarkers by LC-MS/MS.

      Cummings, Jeffrey; Unwin, Richard D; Veenstra, Timothy D; University of Manchester, Manchester, UK. jcummings@picr.man.ac.uk (2009-05-01)
    • Quantitative mass spectrometry-based techniques for clinical use: biomarker identification and quantification.

      Simpson, Kathryn L; Whetton, Anthony D; Dive, Caroline; Paterson Institute for Cancer Research, University of Manchester, Wilmslow Road, Manchester, M20 4BX, United Kingdom. KSimpson@PICR.man.ac.uk (2009-05-01)
      The potential for development of personalised medicine through the characterisation of novel biomarkers is an exciting prospect for improved patient care. Recent advances in mass spectrometric (MS) techniques, liquid phase analyte separation and bioinformatic tools for high throughput now mean that this goal may soon become a reality. However, there are challenges to be overcome for the identification and validation of robust biomarkers. Bio-fluids such as plasma and serum are a rich source of protein, many of which may reflect disease status, and due to the ease of sampling and handling, novel blood borne biomarkers are very much sought after. MS-based methods for high throughput protein identification and quantification are now available such that the issues arising from the huge dynamic range of proteins present in plasma may be overcome, allowing deep mining of the blood proteome to reveal novel biomarker signatures for clinical use. In addition, the development of sensitive MS-based methods for biomarker validation may bypass the bottleneck created by the need for generation and usage of reliable antibodies prior to large scale screening. In this review, we discuss the MS-based methods that are available for clinical proteomic analysis and highlight the progress made and future challenges faced in this cutting edge area of research.
    • Cd133: a marker of transit amplification rather than stem cell phenotype in the prostate?

      Grey, Benjamin R; Oates, Jeremy E; Brown, Michael D; Clarke, Noel W; Genito-Urinary Cancer Research Group, University of Manchester Paterson Institute for Cancer Research, Manchester, UK. bengrey@doctors.org.uk (2009-04)
    • SRC-induced disassembly of adherens junctions requires localized phosphorylation and degradation of the rac activator tiam1.

      Woodcock, Simon A; Rooney, Claire M; Liontos, Michalis; Connolly, Yvonne; Zoumpourlis, Vassilis; Whetton, Anthony D; Gorgoulis, Vassilis G; Malliri, Angeliki; Cell Signalling Group, Cancer Research UK Paterson Institute for Cancer Research, University of Manchester, Manchester, UK. (2009-03-13)
      The Rac activator Tiam1 is required for adherens junction (AJ) maintenance, and its depletion results in AJ disassembly. Conversely, the oncoprotein Src potently induces AJ disassembly and epithelial-mesenchymal transition (EMT). Here, we show that Tiam1 is phosphorylated on Y384 by Src. This occurs predominantly at AJs, is required for Src-induced AJ disassembly and cell migration, and creates a docking site on Tiam1 for Grb2. We find that Tiam1 is associated with ERK. Following recruitment of the Grb2-Sos1 complex, ERK becomes activated and triggers the localized degradation of Tiam1 at AJs, likely involving calpain proteases. Furthermore, we demonstrate that, in human tumors, Y384 phosphorylation positively correlates with Src activity, and total Tiam1 levels are inversely correlated. Thus, our data implicate Tiam1 phosphorylation and consequent degradation in Src-mediated EMT and resultant cell motility and establish a paradigm for regulating local concentrations of Rho-GEFs.
    • THOC5 couples M-CSF receptor signaling to transcription factor expression.

      Carney, Louise; Pierce, Andrew; Rijnen, Marco; Gonzalez Sanchez, M Belen; Hamzah, Hajja G; Zhang, Liqun; Tamura, Teruko; Whetton, Anthony D; Stem Cell and Leukaemia Proteomics laboratory, Faculty of Medical and Human Sciences, University of Manchester, Christie Hospital, Wilmslow Road, Manchester M20 9BX, UK. (2009-02)
      THOC5 is a nuclear/cytoplasmic protein member of the spliceosome complex which potentiates C/EBP expression in adipocyte differentiation. As C/EBP family members are important regulators of myelopoiesis and THOC5 is highly expressed in neutrophil/macrophage progenitor cells we assessed the role of THOC5 in cytokine-stimulated monocytic development. M-CSF stimulated maturation of the NFS60 cell line was associated with enhanced THOC5 expression and phosphorylation. THOC5 was also shown to form a complex with C/EBPbeta. Ectopic expression of THOC5 mimicked M-CSF mediated cell maturation and enhanced protein expression of the myeloid transcription factors C/EBPbeta, C/EBPalpha, Pu-1 and also GAB2 (a PI-3 Kinase and macrophage development regulator). Increased THOC5 expression also mimicked M-CSF stimulated increases in the lipid second messenger PtdInsP(3). Inhibition of THOC5-induced increases in PtdInsP(3) levels abrogated the elevated levels of C/EBPbeta. Thus THOC5 expression can potentiate receptor signalling to transcription factor expression and monocyte differentiation.
    • Investigating FTIR based histopathology for the diagnosis of prostate cancer.

      Baker, Matthew J; Gazi, Ehsan; Brown, Michael D; Shanks, Jonathan H; Clarke, Noel W; Gardner, Peter; Manchester Interdisciplinary Biocentre, Centre for Instrumentation and Analytical Science, School of Chemical Engineering and Analytical Science, The University of Manchester, 131 Princess Street, Manchester, UK. (2009-02)
      Prostate cancer is the most common gender specific cancer. The current gold standard for diagnosis, histopathology, is subjective and limited by variation between different pathologists. The diagnostic problems associated with the correct grading and staging of prostate cancer (CaP) has led to an interest in the development of spectroscopic based diagnostic techniques. FTIR microspectroscopy used in combination with a Principal Component Discriminant Function Analysis (PC-DFA) was applied to investigate FTIR based histopathology for the diagnosis of CaP. In this paper we report the results of a large patient study in which FTIR has been proven to grade CaP tissue specimens to a high degree of sensitivity and specificity.
    • Classification of fixed urological cells using Raman tweezers.

      Harvey, Tim J; Hughes, Caryn; Ward, Andrew D; Faria, Elsa Correia; Henderson, Alex; Clarke, Noel W; Brown, Michael D; Snook, Richard D; Gardner, Peter; School of Chemical Engineering and Analytical Science, Manchester Interdisciplinary Biocentre, University of Manchester, 131 Princess Street, Manchester, UK. (2009-02)
      In this paper we report on preliminary investigations into using Raman tweezers to classify urological cell lines. This builds on earlier work within the group, whereby Raman tweezer methodologies were developed, and the application of this technique to differentiate between live prostate cancer (CaP) and bladder cells lines (PC-3 and MGH-U1 respectively) was demonstrated.In this present study we analysed chemically fixed cells using two different fixative methods; SurePath (a commercial available liquid based cytology media) and 4% v/v formalin/PBS fixatives. The study has been expanded from our previous live cell study to include the androgen sensitive CaP cell line LNCaP, primary benign prostate hyperplasia (BPH) cells as well as primary urethral cells. Raman light from the cells was collected using a 514.5 nm Ar-ion laser excitation source in back-scattering configuration mode.Principal component-linear discriminate analysis (PC-LDA) models of resulting cell spectra were generated and these were validated using a blind comparison. Sensitivities and specificities of > 72% and 90% respectively, for SurePath fixed cells, and > 93% and 98% respectively for 4% v/v formalin/PBS fixed cells was achieved. The higher prediction results for the formalin fixed cells can be attributed to a better signal-to-noise ratio for spectra obtained from these cells.Following on from this work, urological cell lines were exposed to urine for up to 12 hours to determine the effect of urine on the ability to classify these cells. Results indicate that urine has no detrimental effect on prediction results.
    • Nuclear localization of the pre-mRNA associating protein THOC7 depends upon its direct interaction with Fms tyrosine kinase interacting protein (FMIP).

      El Bounkari, Omar; Guria, Anuja; Klebba-Faerber, Sabine; Claussen, Maike; Pieler, Tomas; Griffiths, John R; Whetton, Anthony D; Koch, Alexandra; Tamura, Teruko; Institut fuer Biochemie, OE4310 Medizinische Hochschule Hannover, Hannover, Germany. (2009-01-05)
      THOC7 and Fms-interacting protein (FMIP) are members of the THO complex that associate with the mRNA export apparatus. FMIP is a nucleocytoplasmic shuttling protein with a nuclear localization signal (NLS), whereas THOC7 does not contain a typical NLS motif. We show here that THOC7 (50-137, amino acid numbers) binds to the N-terminal portion (1-199) of FMIP directly. FMIP is detected mainly in the nucleus. In the absence of exogenous FMIP, THOC7 resides mainly in the cytoplasm, while in the presence of FMIP, THOC7 is transported into the nucleus with FMIP. Furthermore, THOC7 lacking the FMIP binding site does not co-localize with FMIP, indicating that THOC7/FMIP interaction is required for nuclear localization of THOC7.
    • Molecular mechanisms of metastasis in prostate cancer.

      Clarke, Noel W; Hart, Claire A; Brown, Michael D; 1Genito-Urinary Cancer Research Group, School of Cancer and Imaging Sciences, Paterson Institute for Cancer Research, Christie Hospital, University of Manchester, Manchester M20 4BX, UK. (2009-01)
      Prostate cancer (PCa) preferentially metastasizes to the bone marrow stroma of the axial skeleton. This activity is the principal cause of PCa morbidity and mortality. The exact mechanism of PCa metastasis is currently unknown, although considerable progress has been made in determining the key players in this process. In this review, we present the current understanding of the molecular processes driving PCa metastasis to the bone.Asian Journal of Andrology (2009) 11: 57-67. doi: 10.1038/aja.2008.29; published online 1 December 2008.
    • Comparison of predicted and clinical response to radiotherapy: a radiobiology modelling study.

      Hedman, Mattias; Björk-Eriksson, Thomas; Mercke, Claes; West, Catharine M L; Hesselius, Patrick; Brodin, Ola; Department of Oncology, Karolinska University Hospital, Karolinska Institutet, Stockholm, Sweden. mattias.hedman@ki.se (2009)
      INTRODUCTION: A model to predict clinical outcome after radiation therapy would be a valuable aid in the effort of developing more tailored treatment regimes for different patients. In this work we evaluate the clinical utility of a model that incorporates the following individually measured radiobiology parameters: intrinsic radiosensitivity, proliferation and number of clonogenic cells. The hypothesis underlying the study was that the incorporation of individually measured tumour parameters in a model would increase its reliability in predicting treatment outcome compared with the use of average population derived data. MATERIAL AND METHODS: Forty-six patients with head and neck tumours were analyzed, the majority of whom received both external beam radiotherapy and brachytherapy. Eighteen patients received external beam treatment alone and statistical analyses were carried out on this subgroup. RESULTS: Four of the 18 patients had a >95% calculated probability of cure and none developed a local recurrence resulting in a negative predictive value of 100% (compared with 67% for population-derived data). The sensitivity of the model in predicting local recurrence was 75% (compared with 38% for population-derived data). Using a model that incorporated individually measured radiobiology data, there was a statistically significant difference in local control levels for patients with >95% and <5% predicted probability of local control (chi(2), p = 0.04). DISCUSSION: This study suggests, therefore, that incorporation of measured biological data within a radiobiological model improves its ability to predict radiation therapy outcome compared with the use of population-derived data.
    • FTIR-based spectroscopic analysis in the identification of clinically aggressive prostate cancer.

      Baker, Matthew J; Gazi, Ehsan; Brown, Michael D; Shanks, Jonathan H; Gardner, Peter; Clarke, Noel W; Manchester Interdisciplinary Biocentre, Centre for Instrumentation and Analytical Science, School of Chemical Engineering and Analytical Science, The University of Manchester, Manchester, M1 7DN, UK. M.J.Baker@manchester.ac.uk (2008-12-02)
      Fourier transform infrared (FTIR) spectroscopy is a vibrational spectroscopic technique that uses infrared radiation to vibrate molecular bonds within the sample that absorbs it. As different samples contain different molecular bonds or different configurations of molecular bonds, FTIR allows us to obtain chemical information on molecules within the sample. Fourier transform infrared microspectroscopy in conjunction with a principal component-discriminant function analysis (PC-DFA) algorithm was applied to the grading of prostate cancer (CaP) tissue specimens. The PC-DFA algorithm is used alongside the established diagnostic measures of Gleason grading and the tumour/node/metastasis system. Principal component-discriminant function analysis improved the sensitivity and specificity of a three-band Gleason score criterion diagnosis previously reported by attaining an overall sensitivity of 92.3% and specificity of 99.4%. For the first time, we present the use of a two-band criterion showing an association of FTIR-based spectral characteristics with clinically aggressive behaviour in CaP manifest as local and/or distal spread. This paper shows the potential for the use of spectroscopic analysis for the evaluation of the biopotential of CaP in an accurate and reproducible manner.
    • Quantum dots light up pathology.

      Tholouli, E; Sweeney, Elizabeth; Barrow, E; Clay, V; Hoyland, Judith A; Byers, Richard J; Department of Clinical Haematology, Manchester Royal Infirmary, Oxford Road, Manchester, UK. (2008-11)
      Quantum dots (QDs) are novel nanocrystal fluorophores with extremely high fluorescence efficiency and minimal photobleaching. They also possess a constant excitation wavelength together with sharp and symmetrical tunable emission spectra. These unique optical properties make them near-perfect fluorescent markers and there has recently been rapid development of their use for bioimaging. QDs can be conjugated to a wide range of biological targets, including proteins, antibodies, and nucleic acid probes, rendering them of particular interest to pathology researchers. They have been used in multiplex immunohistochemistry and in situ hybridization, which when combined with multispectral imaging, has enabled quantitative measurement of gene expression in situ. QDs have also been used for live in vivo animal imaging and are now being applied to an ever-increasing range of biological problems. These are detailed in this review, which also acts to outline the important advances that have been made in their range of applications. The relative novelty of QDs can present problems in their practical use and guidelines for their application are given.
    • Quantitative multiplexed quantum dot immunohistochemistry.

      Sweeney, Elizabeth; Ward, Timothy H; Gray, N; Womack, C; Jayson, Gordon C; Hughes, Andrew; Dive, Caroline; Byers, Richard J; Clinical and Experimental Pharmacology, Paterson Institute for Cancer Research, Wilmslow Road, Manchester, 420 4BX, UK. (2008-09-19)
      Quantum dots are photostable fluorescent semiconductor nanocrystals possessing wide excitation and bright narrow, symmetrical, emission spectra. These characteristics have engendered considerable interest in their application in multiplex immunohistochemistry for biomarker quantification and co-localisation in clinical samples. Robust quantitation allows biomarker validation, and there is growing need for multiplex staining due to limited quantity of clinical samples. Most reported multiplexed quantum dot staining used sequential methods that are laborious and impractical in a high-throughput setting. Problems associated with sequential multiplex staining have been investigated and a method developed using QDs conjugated to biotinylated primary antibodies, enabling simultaneous multiplex staining with three antibodies. CD34, Cytokeratin 18 and cleaved Caspase 3 were triplexed in tonsillar tissue using an 8h protocol, each localised to separate cellular compartments. This demonstrates utility of the method for biomarker measurement enabling rapid measurement of multiple co-localised biomarkers on single paraffin tissue sections, of importance for clinical trial studies.
    • Characterization of the Hoechst 33342 side population from normal and malignant human renal epithelial cells.

      Addla, Sanjai K; Brown, Michael D; Hart, Claire A; Ramani, Vijay A C; Clarke, Noel W; Genito-Urinary Cancer Research Group, School of Cancer and Imaging Sciences, Paterson Institute for Cancer Research, University of Manchester, Wilmslow Road, Manchester, UK. (2008-09)
      The fundamental changes which predispose for renal cell carcinoma (RCC) are poorly characterized. It is hypothesized that "cancer stem cells" may be influential in carcinogenesis, and the epithelial side population (SP) is enriched for stemlike cells in other epithelial cancers. In this study, we have isolated and characterized the SP and non-SP (NSP) populations from normal (NK) and malignant (RCC) human kidney tissue. NK specimens were taken from patients undergoing non-renal cancer surgery and paired malignant and macroscopically normal tissue samples were taken from patients undergoing surgery for RCC. The Hoechst 33342 dye efflux technique was used to isolate epithelial SP and NSP from normal and malignant human renal tissue. Cellular subpopulations were phenotyped for lineage, cell cycle, and putative stem cell markers, and functionally characterized using in vitro colony-forming and proliferation assays. The SP constituted 3.8 +/- 0.4 and 5.9 +/- 0.9% of epithelial cells in NK and RCC, respectively, of which 14.1 +/- 3.5 and 13.2 +/- 3.6% were shown to be in G(0). SP cells demonstrated greater proliferative potential in colony-forming efficiency, long-term culture, and spheroids assays and were shown to be maintained upon tissue culture passage. We have shown that the renal SP is enriched for quiescent cells, with a high proliferative capacity and stemlike properties. The population is, however, heterogeneous, confirming that the terms "SP cell" and "stem cell" cannot be used interchangeably.
    • Endopolyploidy in irradiated p53-deficient tumour cell lines: persistence of cell division activity in giant cells expressing Aurora-B kinase.

      Erenpreisa, Jekaterina; Ivanov, Andrei; Wheatley, Sally P; Kosmacek, Elizabeth A; Ianzini, Fiorenza; Anisimov, Alim P; Mackey, Mike; Davis, Paul J; Plakhins, Gregory; Illidge, Timothy M; et al. (2008-09)
      Recent findings including computerised live imaging suggest that polyploidy cells transiently emerging after severe genotoxic stress (and named 'endopolyploid cells') may have a role in tumour regrowth after anti-cancer treatment. Until now, mostly the factors enabling metaphase were studied in them. Here we investigate the mitotic activities and the role of Aurora-B, in view of potential depolyploidisation of these cells, because Aurora-B kinase is responsible for coordination and completion of mitosis. We observed that endopolyploid giant cells are formed via different means in irradiated p53 tumours, by: (1) division/fusion of daughter cells creating early multi-nucleated cells; (2) asynchronous division/fusion of sub-nuclei of these multi-nucleated cells; (3) a series of polyploidising mitoses reverting replicative interphase from aborted metaphase and forming giant cells with a single nucleus; (4) micronucleation of arrested metaphases enclosing genome fragments; or (5) incomplete division in the multi-polar mitoses forming late multi-nucleated giant cells. We also observed that these activities can release para-diploid cells, although infrequently. While apoptosis typically occurs after a substantial delay in these cells, we also found that approximately 2% of the endopolyploid cells evade apoptosis and senescence arrest and continue some form of mitotic activity. We describe here that catalytically active Aurora-B kinase is expressed in the nuclei of many endopolyploid cells in interphase, as well as being present at the centromeres, mitotic spindle and cleavage furrow during their attempted mitotes. The totally micronucleated giant cells (containing sub-genomic fragments in multiple micronuclei) represented only the minor fraction which failed to undergo mitosis, and Aurora-B was absent from it. These observations suggest that most endopolyploid tumour cells are not reproductively inert and that Aurora-B may contribute to the establishment of resistant tumours post-irradiation.
    • Radiation therapy with tositumomab (B1) anti-CD20 monoclonal antibody initiates extracellular signal-regulated kinase/mitogen-activated protein kinase-dependent cell death that overcomes resistance to apoptosis.

      Ivanov, Andrei; Krysov, Sergei; Cragg, Mark S; Illidge, Timothy M; School of Cancer and Imaging Sciences, CRUK Paterson Institute for Cancer Research, University of Manchester, United Kingdom. (2008-08-01)
      PURPOSE: The use of targeted radiation therapy (RT) in conjunction with anti-CD20 monoclonal antibodies (mAb) delivers high clinical response rates in B-cell lymphomas as part of radioimmunotherapy. The mechanisms underlying these impressive responses, particularly in patients whose lymphomas have become refractory to chemotherapy, are poorly understood. EXPERIMENTAL DESIGN: In this study, we have investigated the signaling pathways and mode of cell death induced in B-cell lymphoma cells after the combination of RT and either type I (rituximab) or type II (tositumomab/B1) anti-CD20 mAb. RESULTS: Increased tumor cell death was observed when RT was combined with tositumomab, but not rituximab. This additive cell death was found to be mitogen-activated protein kinase/extracellular signal-regulated kinase (ERK)-dependent and could be reversed with mitogen-activated protein/extracellular signal-regulated kinase kinase (MEK) inhibitors, as well as small interfering RNA targeting MEK1/2. Furthermore, we found that this increased death was associated with ERK1/2 nuclear accumulation after tositumomab treatment, which was enhanced in combination with RT. Importantly, although Bcl-2 overexpression resulted in resistance to RT-induced apoptosis, it had no effect on the tumor cell death induced by tositumomab plus RT, indicating a nonapoptotic form of cell death. CONCLUSIONS: These findings indicate that RT and type II anti-CD20 mAb combine to stimulate a prodeath function of the MEK-ERK1/2 pathway, which is able to overcome apoptotic resistance potentially explaining the efficacy of this modality in treating patients with chemoresistant disease.