Noriyuki Kasahara

Imperial College London, London, ENG, United Kingdom

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Publications (106)511.44 Total impact

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    ABSTRACT: We are developing a retroviral replicating vector (RRV) encoding cytosine deaminase (CD) as an anticancer agent for gliomas. Despite its demonstrated natural selectivity for tumors, and other safety features, such a virus could potentially cause off-target effects by productively infecting healthy tissues. Here, we investigated whether incorporation of a hematopoietic lineage-specific microRNA target sequence in RRVs further restricts replication in hematopoietic lineage-derived human cells in vitro and in murine lymphoid tissues in vivo. One or four copies of a sequence perfectly complementary to the guide strand of microRNA 142 3p were inserted into the 3'UTR of the RRV genome expressing the transgene GFP. Viral spread and GFP expression of these vectors in hematopoietic-lineage cells in vitro and in vivo were measured by qPCR, qRT-PCR and flow cytometry. In hematopoietic lineage-derived human cell lines and primary human stimulated PBMCs, vectors containing 142 3pT sequence showed a remarkable decrease in GFP expression relative to the parental vector, and viral spread was not observed over time. In a syngeneic subcutaneous mouse tumor model, RRV with and without the 142 3pT sequences spread equally well in tumor cells, were strongly repressed in blood, bone marrow and spleen, and generated antiviral immune responses. In an immune-deficient mouse model, RRV with 142 3pT sequences were strongly repressed in blood, bone marrow and spleen compared to unmodified RRV. Tissue-specific MicroRNA-based selective attenuation of retroviral replication can maintain antiviral immunity, and if needed, provide an additional safeguard to this delivery platform for gene therapy applications.
    Human gene therapy 05/2014; · 4.20 Impact Factor
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    ABSTRACT: Therapeutic gene transfer is currently being evaluated as a potential therapy for inflammatory bowel disease. This study investigates the safety and therapeutic benefit of a locally administered lentiviral vector encoding murine interleukin-10 in altering the onset and relapse of dextran sodium sulfate induced murine colitis. Lentiviral vectors encoding the reporter genes firefly-luciferase and murine interleukin-10 were administered by intrarectal instillation, either once or twice following an ethanol enema to facilitate mucosal uptake, on Days 3 and 20 in Balb/c mice with acute and relapsing colitis induced with dextran sulfate sodium (DSS). DSS colitis was characterized using clinical disease activity, macroscopic, and microscopic scores. Bioluminescence optical imaging analysis was employed to examine mucosal lentiviral vector uptake and transgene expression. Levels of tumor necrosis factor-alpha and interleukin-6 in homogenates of rectal tissue were measured by ELISA. Biodistribution of the lentiviral vector to other organs was evaluated by real time quantitative PCR. Mucosal delivery of lentiviral vector resulted in significant transduction of colorectal mucosa, as shown by bioluminescence imaging analysis. Lentiviral vector-mediated local expression of interleukin-10 resulted in significantly increased levels of this cytokine, as well as reduced levels of tumor necrosis factor-alpha and interleukin-6, and significantly reduced the clinical disease activity, macroscopic, and microscopic scores of DSS colitis. Systemic biodistribution of locally instilled lentiviral vector to other organs was not detected. Topically-delivered lentiviral vectors encoding interleukin-10 safely penetrated local mucosal tissue and had therapeutic benefit in this DSS model of murine colitis.
    BMC Gastroenterology 04/2014; 14(1):68. · 2.11 Impact Factor
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    ABSTRACT: Despite recent advances in molecular classification, surgery, radiotherapy, and targeted therapies, the clinical outcome of patients with malignant brain tumors remains extremely poor. In this study, we have identified the tetraspan protein epithelial membrane protein-2 (EMP2) as a potential target for glioblastoma (GBM) killing. EMP2 had low or undetectable expression in normal brain, but was highly expressed in GBM as 95% of patients showed some expression of the protein. In GBM cells, EMP2 enhanced tumor growth in vivo in part by upregulating αvβ3 integrin surface expression, activating FAK and Src kinases, and promoting cell migration and invasion. Consistent with these findings, EMP2 expression significantly correlated with activated Src kinase in patient samples and promoted tumor cell invasion using intracranial mouse models. As a proof of principle to determine if EMP2 could serve as a target for therapy, cells were treated using specific anti-EMP2 antibody reagents. These reagents were effective in killing GBM cells in vitro and in reducing tumor load in subcutaneous mouse models. These results support the role of EMP2 in the pathogenesis of GBM and suggest that anti-EMP2 treatment may be a novel therapeutic treatment.
    Journal of Biological Chemistry 03/2014; · 4.65 Impact Factor
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    ABSTRACT: Retroviral replicating vectors (RRVs) have been shown to achieve efficient tumor transduction and enhanced therapeutic benefit in a wide variety of cancer models. Here we evaluated two different RRVs derived from amphotropic murine leukemia virus (AMLV) and gibbon ape leukemia virus (GALV), in human malignant mesothelioma cells. In vitro, both RRVs expressing the green fluorescent protein gene efficiently replicated in most mesothelioma cell lines tested, but not in normal mesothelial cells. Notably, in ACC-MESO-1 mesothelioma cells that were not permissive for AMLV-RRV, the GALV-RRV could spread efficiently in culture and in mice with subcutaneous xenografts by in vivo fluorescence imaging. Next, GALV-RRV expressing the cytosine deaminase prodrug activator gene showed efficient killing of ACC-MESO-1 cells in a prodrug 5-fluorocytosine dose-dependent manner, compared with AMLV-RRV. GALV-RRV-mediated prodrug activator gene therapy achieved significant inhibition of subcutaneous ACC-MESO-1 tumor growth in nude mice. Quantitative reverse transcription PCR demonstrated that ACC-MESO-1 cells express higher PiT-1 (GALV receptor) and lower PiT-2 (AMLV receptor) compared with normal mesothelial cells and other mesothelioma cells, presumably accounting for the distinctive finding that GALV-RRV replicates much more robustly than AMLV-RRV in these cells. These data indicate the potential utility of GALV-RRV-mediated prodrug activator gene therapy in the treatment of mesothelioma.Cancer Gene Therapy advance online publication, 8 November 2013; doi:10.1038/cgt.2013.67.
    Cancer gene therapy 11/2013; · 3.13 Impact Factor
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    ABSTRACT: New treatments are needed for brain metastasis, which is associated with high morbidity and mortality. Two novel cellular and gene therapy modalities were evaluated in xenograft models for human breast cancer. The individual and especially the combined treatments with alloreactive cytotoxic T lymphocytes and replicating retroviral vectors coding for prodrug activating enzymes followed later with nontoxic prodrug demonstrated efficacy without off-target effects.
    Oncoimmunology. 10/2013; 2(10):e25989.
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    ABSTRACT: Several studies have focused on the impact of bone morphogenetic protein (BMP) on prostate cancer homing and growth at distant metastatic sites, but very little on impact at the primary site. Here we used two cell lines, one (E8) isolated from a primary tumor and the other (cE1) from a recurrent tumor arising at the primary site, both from the conditional Pten deletion mouse model of prostatic adenocarcinoma. Over-expression of the BMP antagonist Noggin inhibited proliferation of cE1 cells in vitro while enhancing their ability to migrate. On the other hand cE1/Noggin grafts grown in vivo showed a greater mass and a higher proliferation index than the cE1/Control grafts. For suppression of BMP activity in the context of cancer associated fibroblasts (CAFs), we used Noggin-transduced CAFs from the same mouse model to determine their effect on E8 or cE1 induced tumor growth. CAF/Noggin led to increased tumor mass and greater de-differentiation of the E8 cell as compared to tumors formed in the presence of CAF/Control cells. A trend in increase in the size of the tumor was also noted for cE1 cells when inoculated with CAF/Noggin. Together, the results may point to a potential inhibitory role of BMP in the growth or re-growth of prostate tumor at the primary site. Additionally, results for cE1/Noggin, and cE1 mixed with CAF/Noggin suggested that suppression of BMP activity in the cancer cells may have a stronger growth enhancing effect on the tumor than its suppression in the fibroblastic compartment of the tumor microenvironment.
    Endocrine Related Cancer 09/2013; · 5.26 Impact Factor
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    ABSTRACT: Despite the progress in our understanding of genes essential for stem cell regulation and development, little is known about the factors secreted by stem cells and their effect on tissue regeneration. In particular, the factors secreted by human CD34+ cells remain to be elucidated. We have approached this challenge by performing a cytokine/growth factor microarray analysis of secreted soluble factors in medium conditioned by adherent human CD34+ cells. Thirty-two abundantly secreted factors have been identified, all of which are associated with cell proliferation, survival, tissue repair, and wound healing. The cultured CD34+ cells expressed known stem cell genes such as Nanog, Oct4, Sox2, c-Kit and HoxB4. The conditioned medium containing the secreted factors prevented cell death in liver cells exposed to liver toxin in vitro via inhibition of the caspase-3 signalling pathway. More importantly, in vivo studies using animal models of liver damage demonstrated that injection of the conditioned medium could repair damaged liver tissue (significant reduction in the necroinflammatory activity), as well as enable the animals to survive. Thus, we demonstrate that medium conditioned by human CD34+ cells has the potential for therapeutic repair of damaged tissue in vivo.Molecular Therapy (2013); doi:10.1038/mt.2013.194.
    Molecular Therapy 08/2013; · 7.04 Impact Factor
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    ABSTRACT: Toca 511 (vocimagene amiretrorepvec), an amphotropic retroviral replicating vector (RRV), can successfully and safely deliver a functional, optimized cytosine deaminase (CD) gene to tumors in orthotopic glioma models. This agent, in conjunction with subsequent oral extended-release 5-fluorocytosine (5-FC) (Toca FC), is currently under investigation in patients with recurrent high-grade glioma . Temozolomide (TMZ) with radiation is the most frequently used first-line treatment for patients with glioblastoma, the most common and aggressive form of primary brain cancer in adults. However, subsets of patients with certain genetic alterations do not respond well to TMZ treatment and the overall median survival for patients who respond remains modest, suggesting that combinatorial approaches may be necessary to significantly improve outcomes. We show that in vitro TMZ delays but does not prevent RRV spread, nor interfere with Toca 511+5-FC-mediated cell killing in glioma tumor cells, and in vivo there is no significant hematologic effect from the combination of 5-FC and the clinically relevant dose of TMZ. A synergistic long-term survival advantage is observed in mice bearing an orthotopic TMZ-sensitive glioma after Toca 511 administration followed by coadministration of TMZ and 5-FC. These results provide support for the investigation of this novel combination treatment strategy in patients with newly diagnosed malignant glioma.Cancer Gene Therapy advance online publication, 23 August 2013; doi:10.1038/cgt.2013.51.
    Cancer gene therapy 08/2013; · 3.13 Impact Factor
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    ABSTRACT: Oncolytic virotherapy using adenoviruses has potential for therapeutic benefits in malignant mesothelioma. However, the downregulation of coxsackievirus/adenovirus receptor (CAR) expression is frequently a critical rate-limiting factor that impedes the effectiveness of adenovirus serotype 5 (Ad5)-based vectors in many cancer types. We evaluated CAR (Ad5 receptor) and CD46 [adenovirus serotype 35 (Ad35) receptor] expression in 6 human malignant mesothelioma cell lines. Very low CAR expression was observed in MSTO-211H and NCI-H2052 cells, whereas the other cell lines showed strong expression. In contrast, CD46 was highly expressed in all mesothelioma cell lines. On this basis, we replaced the CAR binding sequence of Ad5 with the CD46 binding sequence of Ad35 in the replication-defective adenoviruses and the tumor-specific midkine promoter-regulated oncolytic adenoviruses. By this fiber modification, the infectivity, virus progeny production, and in vitro cytocidal effect of the adenoviruses were significantly enhanced in low CAR-expressing MSTO-211H and NCI-H2052 cells, resulting in similar or even higher levels in high CAR-expressing mesothelioma cell lines. In MSTO-211H xenograft models, the fiber-modified oncolytic adenovirus significantly enhanced antitumor effect compared to its equivalent Ad5-based vector. Our data demonstrate that Ad35 fiber modification of binding tropism in a midkine promoter-regulated oncolytic Ad5 vector confers transductional targeting to oncolytic adenoviruses, thereby facilitating more effective treatment of malignant mesothelioma. This article is protected by copyright. All rights reserved.
    Cancer Science 08/2013; · 3.48 Impact Factor
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    ABSTRACT: Hepatocellular carcinoma (HCC) occurs predominantly in patients with liver cirrhosis. Here, we show an innovative RNA-based targeted approach to enhance endogenous albumin production whilst reducing liver tumour burden. We designed short-activating RNAs (saRNA) to enhance expression of C/EBPα (CCAAT/enhancer-binding protein-α), a transcriptional regulator and activator of albumin gene expression. Increased levels of both C/EBPα and albumin mRNA in addition to a 3-fold increase in albumin secretion and 50% decrease in cell proliferation was observed in C/EBPα-saRNA transfected HepG2 cells. Intravenous injection of C/EBPα-saRNA in a cirrhotic rat model with multifocal liver tumours increased circulating serum albumin by over 30% showing evidence of improved liver function. Tumour burden decreased by 80% (p = 0.003) with a 40% reduction in a marker of pre-neoplastic transformation. Since C/EBPα has known anti-proliferative activities via retinoblastoma, p21 and cyclins; we used mRNA expression liver cancer specific microarray in C/EBPα-saRNA transfected HepG2 cells to confirm down-regulation of genes strongly enriched for negative regulation of apoptosis, angiogenesis and metastasis. Up-regulated genes were enriched for tumour suppressors and positive regulators of cell differentiation. A quantitative PCR and Western-blot analysis of C/EBPα-saRNA transfected cells suggested that in addition to the known anti-proliferative targets of C/EBPα, we also observed suppression of IL6R, c-Myc and reduced STAT3 phosphorylation. Conclusion: We demonstrate for the first time that a novel injectable saRNA-oligonucleotide that enhances C/EBPα expression successfully reduces tumour burden and simultaneously improves liver function in a clinically relevant liver cirrhosis/HCC model. (Hepatology 2013;).
    Hepatology 08/2013; · 12.00 Impact Factor
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    ABSTRACT: PURPOSE: Individual or combined strategies of cellular therapy with alloreactive cytotoxic T lymphocytes (alloCTL) and gene therapy employing retroviral replicating vectors (RRV) encoding a suicide prodrug activating gene were explored for the treatment of breast tumors metastatic to the brain. EXPERIMENTAL DESIGN: AlloCTL, sensitized to the human leukocyte antigens of MDA-MB-231 breast cancer cells, were examined in vitro for anti-tumor functionality toward breast cancer targets. RRV encoding the yeast cytosine deaminase (CD) gene was tested in vivo for virus spread, ability to infect, and kill breast cancer targets when exposed to 5-fluorocytosine (5-FC). Individual and combination treatments were tested in subcutaneous and intracranial xenograft models with 231BR, a brain tropic variant. RESULTS: AlloCTL preparations were cytotoxic, proliferated and produced interferon-gamma when coincubated with target cells displaying relevant HLA. In vivo, intratumorally-placed alloCTL trafficked through one established intracranial 231BR focus to another in contralateral brain and induced tumor cell apoptosis. RRV-CD efficiently spread in vivo, infected 231BR and induced their apoptosis upon 5-FC exposure. Subcutaneous tumor volumes were significantly reduced in alloCTL and/or gene therapy treated groups compared to control groups. Mice with established intracranial 231BR tumors treated with combined alloCTL and RRV-CD had a median survival of 97.5 days compared with single modalities (50-83 days); all experimental treatment groups survived significantly longer than sham-treated groups (median survivals 31.5 or 40 days) and exhibited good safety/toxicity profiles. CONCLUSION: The results indicate combining cellular and suicide gene therapies is a viable strategy for the treatment of established breast tumors in the brain.
    Clinical Cancer Research 06/2013; · 7.84 Impact Factor
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    ABSTRACT: We have recently developed a novel and highly efficient strategy that exclusively uses the purine analog 6-thioguanine (6TG) for both pretransplantation conditioning and post-transplantation chemoselection of hypoxanthine-guanine phosphoribosyltransferase (HPRT)-deficient bone marrow (BM). In a mouse BM transplantation model, combined 6TG preconditioning and in vivo chemoselection consistently achieved >95% engraftment of HPRT-deficient donor BM and long-term reconstitution of histologically and immunophenotypically normal hematopoiesis in both primary and secondary recipients, without significant toxicity and in the absence of any other cytotoxic conditioning regimen. To translate this strategy for combined 6TG conditioning and chemoselection into a clinically feasible approach, it is necessary to develop methods for genetic modification of normal hematopoietic stem cells (HSC) to render them HPRT-deficient and thus 6TG-resistant. Here we investigated a strategy to reduce HPRT expression and thereby confer protection against 6TG myelotoxicity to primary murine BM cells by RNA interference (RNAi). Accordingly, we constructed and validated a lentiviral gene transfer vector expressing short-hairpin RNA (shRNA) that targets the murine HPRT gene. Our results showed that lentiviral vector-mediated delivery of HPRT-targeted shRNA could achieve effective and long-term reduction of HPRT expression. Furthermore, in both an established murine cell line as well as in primary murine BM cells, lentiviral transduction with HPRT-targeted shRNA was associated with enhanced resistance to 6TG cytotoxicity in vitro. Hence this represents a translationally feasible method to genetically engineer HSC for implementation of 6TG-mediated preconditioning and in vivo chemoselection.
    Transplantation Proceedings 06/2013; 45(5):2040-4. · 0.95 Impact Factor
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    ABSTRACT: In the present study, we compared the therapeutic effect of tumor-selective retroviral replicating vectors (RRV) expressing the yeast cytosine deaminase (CD) delivered by convection-enhanced delivery (CED) or simple injection, followed by systemic administration of the pro-drug, 5-fluorocytosine (5-FC). Treatment with RRV-CD and systemic 5-FC significantly increased survival in rodent U87MG glioma model in comparison with controls (P<0.01). Interestingly, CED of RRV-CD followed by 5-FC further enhanced survival in this animal model in comparison with intra-tumoral injection of RRV-CD, followed by systemic 5-FC (P<0.05). High expression levels of Ki-67 were found in untreated tumors compared with treated. Untreated tumors were also much larger than treated. CED resulted in excellent distribution of RRV while only partial distribution of RRV was obtained after injection. Furthermore, RRV-CD and CD were also found in tumors from treated rats at study end points. These results demonstrated that RRV vectors may efficiently transduce and stably propagate in malignant human glioma, thereby achieving a significant in situ amplification effect after initial administration. We conclude that delivery of RRV into the glioma by CED provides much wider vector distribution than simple injection, and this correlated with better therapeutic outcomes.Cancer Gene Therapy advance online publication, 24 May 2013; doi:10.1038/cgt.2013.25.
    Cancer gene therapy 05/2013; · 3.13 Impact Factor
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    ABSTRACT: We provide an overview of the latest developments in cancer gene therapy-from the bench to early-stage clinical trials. We describe the most recent work of worldwide teams including experienced scientists and clinicians, reflecting the recent emergence of gene therapy from the 'Valley of Death'. The treatment efficacy of clinical gene therapy has now been shown in a number of diseases including cancer and we are observing a renewed interest by big pharmaceutical and biotechnology companies most obviously demonstrated by Amgen's acquisition of Biovex for up to USD$1 billion. There is an opportunity to be cautiously hopeful regarding the future of gene therapy in the clinic and we review here some of the most recent progress in the field.Cancer Gene Therapy advance online publication, 1 February 2013; doi:10.1038/cgt.2012.93.
    Cancer gene therapy 02/2013; · 3.13 Impact Factor
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    ABSTRACT: Upon functional loss of insulin producing islet β-cells, some patients with diabetes become dependent on life-long insulin supplementation therapy. Bioengineering surrogate insulin producing cells is an alternative replacement strategy. We have developed a novel approach using short-activating RNA oligonucleotides to differentiate adult human CD34(+) cells into insulin-secreting cells. By transfecting RNA to increase transcript levels of the master regulator of insulin biosynthesis, v-maf musculoaponeurotic fibrosarcoma oncogene homolog A (MafA), several pancreatic endodermal genes were upregulated during the differentiation procedure. These included Pancreatic and duodenal homeobox gene-1 (PDX1), Neurogenin 3, NeuroD, and NK6 homeobox 1 (NKx6-1). Differentiated CD34(+) cells also expressed glucokinase, glucagon-like peptide 1 receptor (GLP1R), sulfonylurea receptor-1 (SUR1) and phogrin-all essential for glucose sensitivity and insulin secretion. The differentiated cells appropriately processed C-peptide and insulin in response to increasing glucose stimulation as shown by enzyme-linked immunosorbent assay (ELISA), fluorescence-activated cell sorting analysis, western blotting, and immunofluorescence staining. We provide a new approach using short-activating RNA in developing insulin producing surrogate cells for treating diabetes.Molecular Therapy - Nucleic Acids (2013) 2, e97; doi:10.1038/mtna.2013.23; advance online publication 4 June 2013.
    Molecular therapy. Nucleic acids. 01/2013; 2:e97.
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    ABSTRACT: A vast amount of research on the regulation of gene expression has relied on plasmid reporter assays. In this study, we show that plasmids widely used for this purpose constitutively produce substantial amounts of RNA from a TATA-containing cryptic promoter within the origin of replication. Readthrough of these RNAs into the intended transcriptional unit potently stimulated reporter activity when the inserted test sequence contained a 3' splice site (ss). We show that two human sequences, originally reported to be internal ribosome entry sites and later to instead be promoters, mimic both types of element in dicistronic reporter assays by causing these cryptic readthrough transcripts to splice in patterns that allow efficient translation of the downstream cistron. Introduction of test sequences containing 3' ss into monocistronic luciferase reporter vectors widely used in the study of transcriptional regulation also created the false appearance of promoter function via the same mechanism. Across a large number of variants of these plasmids, we found a very highly significant correlation between reporter activity and levels of such spliced readthrough transcripts. Computational estimation of the frequency of cryptic 3' ss in genomic sequences suggests that misattribution of cis-regulatory function may be a common occurrence.
    Nucleic Acids Research 05/2012; 40(15):7280-90. · 8.28 Impact Factor
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    ABSTRACT: Retroviral replicating vectors (RRVs) are a nonlytic alternative to oncolytic replicating viruses as anticancer agents, being selective both for dividing cells and for cells that have defects in innate immunity and interferon responsiveness. Tumor cells fit both these descriptions. Previous publications have described a prototype based on an amphotropic murine leukemia virus (MLV), encoding yeast cytosine deaminase (CD) that converts the prodrug 5-fluorocytosine (5-FC) to the potent anticancer drug, 5-fluorouracil (5-FU) in an infected tumor. We report here the selection of one lead clinical candidate based on a general design goal to optimize the genetic stability of the virus and the CD activity produced by the delivered transgene. Vectors were tested for titer, genetic stability, CD protein and enzyme activity, ability to confer susceptibility to 5-FC, and preliminary in vivo antitumor activity and stability. One vector, Toca 511, (aka T5.0002) encoding an optimized CD, shows a threefold increased specific activity in infected cells over infection with the prototype RRV and shows markedly higher genetic stability. Animal testing demonstrated that Toca 511 replicates stably in human tumor xenografts and, after 5-FC administration, causes complete regression of such xenografts. Toca 511 (vocimagene amiretrorepvec) has been taken forward to preclinical and clinical trials.
    Molecular Therapy 05/2012; 20(9):1689-98. · 7.04 Impact Factor
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    ABSTRACT: As the interest in gene therapy increases, the development of an efficient and reliable means to monitor gene delivery and expression in patients is becoming more important. An ideal imaging modality would be non-invasive, allowing for repeated imaging, thus validating stages subsequent to vector administration and allowing for the improvement of clinical protocols. Positron Emission Tomography (PET) has been employed for some time in clinical imaging and has in more recent years been adapted to enable imaging in small animal models, including gene therapy models for a range of diseases. PET imaging is based on the detection of trace quantities of positron-emitting molecular probe within cells postadministration, permitting imaging of target molecules in vivo, and numerous tracers have been developed for a wide range of applications, including imaging of reporter gene activity. Use of radiolabelled substrates that interact with specific transgene proteins, has identified a number of reporter genes that are suitable for imaging vector mediated gene delivery and expression in both pre-clinical and clinical situations. These reporter genes enable non-invasive analysis of the location, level and kinetics of transgene activity. Among the various imaging modalities in existence, the PET approach displays arguably the optimum characteristics in terms of sensitivity and quantitation for in vivo gene expression measurements. Given the existing availability of PET scanning equipment and expertise in hospitals, this imaging modality represents the most clinically applicable means of analysing gene therapy in patients. This review outlines the principles of PET imaging in the context of gene and cell therapy at both pre-clinical and clinical levels, comparing PET with other relevant modalities, and describes the progress to date in this field.
    Current Gene Therapy 02/2012; 12(1):20-32. · 5.32 Impact Factor
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    ABSTRACT: The ability to track microbes in real time in vivo is of enormous value for preclinical investigations in infectious disease or gene therapy research. Bacteria present an attractive class of vector for cancer therapy, possessing a natural ability to grow preferentially within tumours following systemic administration. Bioluminescent Imaging (BLI) represents a powerful tool for use with bacteria engineered to express reporter genes such as lux. BLI is traditionally used as a 2D modality resulting in images that are limited in their ability to anatomically locate cell populations. Use of 3D diffuse optical tomography can localize the signals but still need to be combined with an anatomical imaging modality like micro-Computed Tomography (μCT) for interpretation.In this study, the non-pathogenic commensal bacteria E. coli K-12 MG1655 and Bifidobacterium breve UCC2003, or Salmonella Typhimurium SL7207 each expressing the luxABCDE operon were intravenously (i.v.) administered to mice bearing subcutaneous (s.c) FLuc-expressing xenograft tumours. Bacterial lux signal was detected specifically in tumours of mice post i.v.-administration and bioluminescence correlated with the numbers of bacteria recovered from tissue. Through whole body imaging for both lux and FLuc, bacteria and tumour cells were co-localised. 3D BLI and μCT image analysis revealed a pattern of multiple clusters of bacteria within tumours. Investigation of spatial resolution of 3D optical imaging was supported by ex vivo histological analyses. In vivo imaging of orally-administered commensal bacteria in the gastrointestinal tract (GIT) was also achieved using 3D BLI. This study demonstrates for the first time the potential to simultaneously image multiple BLI reporter genes three dimensionally in vivo using approaches that provide unique information on spatial locations.
    PLoS ONE 01/2012; 7(1):e30940. · 3.73 Impact Factor
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    ABSTRACT: The use of replication-competent viruses for the treatment of cancer is an emerging technology that shows significant promise. Among the various different types of viruses currently being developed as oncolytic agents, retroviral replicating vectors (RRVs) possess unique characteristics that allow highly efficient, non-lytic, and tumor-selective gene transfer. By retaining all of the elements necessary for viral replication, RRVs are capable of transmitting genes via exponential in situ amplification. Their replication-competence also provides a powerful means whereby novel and useful RRV variants can be generated using natural selection. Their stringent requirement for cell division in order to achieve productive infection, and their preferential replication in cells with defective innate immunity, confer a considerable degree of natural specificity for tumors. Furthermore, their ability to integrate stably into the genome of cancer cells, without immediate cytolysis, contributes to long-lasting therapeutic efficacy. Thus, RRVs show much promise as therapeutic agents for cancer and are currently being tested in the clinic. Here we describe experimental methods for their production and quantitation, for adaptive evolution and natural selection to develop novel or improved RRV, and for in vitro and in vivo assessment of the therapeutic efficacy of RRVs carrying prodrug activator genes for treatment of cancer.
    Methods in enzymology 01/2012; 507:199-228. · 1.90 Impact Factor

Publication Stats

2k Citations
511.44 Total Impact Points


  • 2012–2013
    • Imperial College London
      • Department of Surgery and Cancer
      London, ENG, United Kingdom
    • University College Cork
      • Cork Cancer Research Centre
      Cork, M, Ireland
  • 2006–2013
    • Children's Hospital Los Angeles
      • Division of Hospital Medicine
      Los Angeles, California, United States
  • 2001–2013
    • University of California, Los Angeles
      • • Department of Medicine
      • • Department of Molecular and Medical Pharmacology
      Los Angeles, CA, United States
    • Keck School of Medicine USC
      Los Angeles, California, United States
  • 2011
    • Hyogo College of Medicine
      • Institute for Advanced Medical Sciences
      Nishinomiya, Hyogo-ken, Japan
  • 2008–2010
    • National Chung Cheng University
      • Department of Life Science
      Chia-i-hsien, Taiwan, Taiwan
    • Molecular and Cellular Biology Program
      Seattle, Washington, United States
  • 2009
    • University of Southampton
      Southampton, England, United Kingdom
  • 2007
    • CSU Mentor
      Long Beach, California, United States
  • 2003–2007
    • Memorial Sloan-Kettering Cancer Center
      New York City, New York, United States
  • 1999–2006
    • University of Southern California
      • • Keck School of Medicine
      • • Institute for Genetic Medicine
      Los Angeles, California, United States