Therapy Strategies (therapy + strategy)

Distribution by Scientific Domains
Distribution within Medical Sciences

Kinds of Therapy Strategies

  • gene therapy strategy

  • Selected Abstracts

    Molecular epidemiology of tuberculosis in the Tula area, Central Russia, before the introduction of the Directly Observed Therapy Strategy

    S. Dubiley
    Clin Microbiol Infect 2010; 16: 1421,1426 Abstract Tuberculosis remains a major public health concern in Russia and worldwide. Given the great geographical, ethnic, and socio-economic heterogeneities between Russian regions, epidemiological data cannot be generalized from a regional to a country-wide level. We present data on the epidemiology of tuberculosis in Central Russia. We report a high level of resistance to major antitubercular drugs in both new and previously treated patients in the region. The level of drug resistance in new cases was almost twice as high as the estimated average national level. The Mycobacterium tuberculosis strains that circulated in the region were predominantly represented by LAM-RUS and Beijing genotypes. These two lineages were strongly associated with drug resistance and clustering. Using molecular epidemiology techniques, we showed a high interpenetration by M. tuberculosis strains between the prison and civilian populations. A limited number of identical strains were responsible for the majority of drug-resistant tuberculosis cases in both settings. [source]

    Targeting cerebral arteries for gene therapy

    Yoshimasa Watanabe
    After the steady progress towards application of gene therapy to cerebral arterial diseases, several applications, including modification of gene expression in cerebral arteries, are now feasible. There are several possible targets for cerebrovascular gene therapy, and numerous studies have tested gene therapy strategies in animal models of cerebrovascular disorders. However, some major obstacles, especially issues of safety, must be overcome before clinical use in humans. Gene therapy for cerebral arterial diseases is still in its infancy, and many basic and preclinical studies are yet to be done in order to develop effective and safe techniques. [source]

    Gene therapy for haemophilia,yes, but,with non-viral vectors?

    HAEMOPHILIA, Issue 3 2009
    A. LIRAS
    Summary., High-purity plasma-derived and recombinant factors are currently safe and efficient treatment for haemophilia. The mid-term future of haemophilia treatment will involve the use of modified recombinant factors to achieve advantages such as decreased immunogenicity in inhibitor formation and enhanced efficacy as a result of their longer half-life. In the long-term, gene therapy and cell therapy strategies will have to be considered. Achievements in cell therapy to date have been using embryonic stem cells and hepatic sinusoidal endothelial cells. Current gene therapy strategies for haemophilia are based on gene transfer using adeno-associated viruses and non-viral vectors. Gene therapy for haemophilia is justified because it is a chronic disease and because a very regular factor infusion is required that may involve fatal risks and because it is very expensive. Haemophilia is a very good candidate for use of gene therapy protocols because it is a monogenic disease, and even low expression is able to achieve reversion from a severe to a moderate phenotype. The current trends in haemophilia using adeno-associated viral vectors are safe but also involve immunogenicity problems. The other alternatives are non-viral vectors. There have been in recent years relevant advances in non-viral transfection that raise hope for considering this possibility. Several research groups are opting for this experimental alternative. An expression over 5%, representing a moderate phenotype, for a few months with a high safety, regarding vector, transfected cells, and implantation procedure, would already be a great success. This may represent an intermediate protocol in which the expression levels and times obtained are lower and shorter respectively as compared to viral vectors, but which provide a potential greater patient safety. This may more readily win acceptance among both patients and haematologists because fatal events in the past due to HIV/HCV infection may constrain the implementation of viruses as vectors. [source]

    Gene and immune therapy for renal cell carcinoma

    Allan J Pantuck
    Abstract Conventional therapy for metastatic renal cell carcinoma is associated with a poor response rate and few patients are long-term survivors. The occurrence of spontaneous regression and the prolonged latency period between primary tumor removal and the appearance of metastases in some patients suggest the existence of important host immune responses to autologous tumor cells. With the advent of molecular gene transfer techniques and increased knowledge of the basic pathways of immune activation, the field of cancer immunotherapy has finally begun to develop novel and effective approaches for harnessing the immune system as a therapeutic agent. Current immunotherapy and gene therapy strategies, including methods of cytokine delivery and tumor-cell-based vaccines, are presented. [source]

    The impact of the pH value on skin integrity and cutaneous wound healing

    S Schreml
    Abstract The process of cutaneous wound healing comprises three overlapping major phases: inflammation, proliferation and tissue remodelling. However, while mechanisms are studied scientifically on the cellular and subcellular level, there is still a lack of knowledge concerning basic clinical parameters like wound pH or pO2. It could be proven that wound healing is affected by wound pH changes as they can lead to an inhibition of endogenous and therapeutically applied enzymes. Besides, the conformational structure of proteins and their functionality in wound healing is altered. Furthermore, the likelihood of bacterial colonization, which is a common problem in chronic wound pathogenesis, is affected by wound pH alterations. However, wound pH is rarely taken into account in current wound therapy strategies. A routinely performed monitoring of the wound pH and a subsequently adapted wound therapy would most possibly improve chronic wound therapy. [source]

    The promise and challenges of bioengineered recombinant clotting factors

    S. W. PIPE
    Summary., The past 10 years of clinical experience have demonstrated the safety and efficacy of recombinant clotting factors. With the adoption of prophylactic strategies, there has been considerable progress in avoiding the complications of hemophilia. Now, insights from our understanding of clotting factor structure and function, mechanisms of hemophilia and inhibitors, gene therapy advances and a worldwide demand for clotting factor concentrates leave us on the brink of embracing targeted bioengineering strategies to further improve hemophilia therapeutics. The ability to bioengineer recombinant clotting factors with improved function holds promise to overcome some of the limitations in current treatment, the high costs of therapy and increase availability to a broader world hemophilia population. Most research has been directed at overcoming the inherent limitations of rFVIII expression and the inhibitor response. This includes techniques to improve rFVIII biosynthesis and secretion, functional activity, half-life and antigenicity/immunogenicity. Some of these proteins have already reached commercialization and have been utilized in gene therapy strategies, while others are being evaluated in pre-clinical studies. These novel proteins partnered with advances in gene transfer vector design and delivery may ultimately achieve persistent expression of FVIII leading to an effective long-term treatment strategy for hemophilia A. In addition, these novel FVIII proteins could be partnered with new advances in alternative recombinant protein production in transgenic animals yielding an affordable, more abundant supply of rFVIII. Novel rFIX proteins are being considered for gene therapy strategies whereas novel rVIIa proteins are being evaluated to improve the potency and extend their plasma half-life. This review will summarize the status of current recombinant clotting factors and the development and challenges of recombinant clotting factors bioengineered for improved function. [source]

    Remote Liver Injury is Attenuated by Adenovirus-Mediated Gene Transfer of Heme Oxygenase-1 During the Systemic Inflammatory Response Syndrome

    MICROCIRCULATION, Issue 7 2004
    ABSTRACT Objectives: Adenovirus-mediated gene therapy is being investigated with increasing success for future treatment of autoimmune diseases. However, the use of adenoviruses is still limited by inflammatory and immune responses in the target organ. Previous work by the authors' laboratory established that the adenovirus encoding inducible heme oxygenase (Ad-HO-1) does not elicit the acute hepatic inflammation normally caused by adenoviruses, inviting further investigation in models of severe inflammation. Concurrently, there is increasing evidence for an endogenous protective role for heme oxygenase (HO) in the liver during the systemic inflammatory response syndrome (SIRS). Building on our previous results, this study investigated the effect of Ad-HO-1 pretreatment on remote liver injury during normotensive SIRS, induced by bilateral hind limb ischemia and reperfusion. Methods: Microvascular perfusion and hepatocyte death were quantified using established intravital videomicroscopy techniques. Hepatocellular injury and liver function were assessed using blood-borne indicators. Results: Microvascular perfusion deficits and increased hepatocyte death occurred following limb ischemia and 3 h of reperfusion in vehicle-pretreated animals; however, Ad-HO-1 pretreatment prevented these deficits. In contrast, the increase in serum alanine transaminase levels was unaffected by Ad-HO-1 pretreatment. Serum bilirubin levels were increased during systemic inflammation, predominantly in the conjugated form; and, this increase was prevented by administration of Ad-HO-1. Conclusions: These data indicate that gene transfer of inducible HO is an effective method to protect the liver during SIRS, providing incentive for further investigation into gene therapy strategies exploiting this anti-inflammatory enzyme. [source]

    Dephosphorylation of p-ERK1/2 in relation to tumor remission after HER-2 and Raf1 blocking therapy in a conditional mouse tumor model,,

    Carolin K. Hausherr
    Abstract Several studies have shown that HER-2/neu (erbB-2) blocking therapy strategies can cause tumor remission. However, the responsible molecular mechanisms are not yet known. Both ERK1/2 and Akt/PKB are critical for HER-2-mediated signal transduction. Therefore, we used a mouse tumor model that allows downregulation of HER-2 in tumor tissue by administration of anhydrotetracycline (ATc). Switching-off HER-2 caused a rapid tumor remission by more than 95% within 7 d of ATc administration compared to the volume before switching-off HER-2. Interestingly, HER-2 downregulation caused a dephosphorylation of p-ERK1/2 by more than 80% already before tumor remission occurred. Levels of total ERK protein were not influenced. In contrast, dephosphorylation of p-Akt occurred later, when the tumor was already in remission. These data suggest that in our HER-2 tumor model dephosphorylation of p-ERK1/2 may be more critical for tumor remission than dephosphorylation of p-Akt. To test this hypothesis we used a second mouse tumor model that allows ATc controlled expression of BXB-Raf1 because the latter constitutively signals to ERK1/2, but cannot activate Akt/PKB. As expected, downregulation of BXB-Raf1 in tumor tissue caused a strong dephosphorylation of p-ERK1/2, but did not decrease levels of p-Akt. Interestingly, tumor remission after switching-off BXB-Raf1 was similarly efficient as the effect of HER-2 downregulation, despite the lack of p-Akt dephosphorylation. In conclusion, two lines of evidence strongly suggest that dephosphorylation of p-ERK1/2 and not that of p-Akt is critical for the rapid tumor remission after downregulation of HER-2 or BXB-Raf1 in our tumor model: (i) dephosphorylation of p-ERK1/2 but not that of p-Akt precedes tumor remission after switching-off HER-2 and (ii) downregulation of BXB-Raf1 leads to a similarly efficient tumor remission as downregulation of HER-2, although no p-Akt dephosphorylation was observed after switching-off BXB-Raf1. © 2006 Wiley-Liss, Inc. [source]

    Nanoparticle phagocytosis and cellular stress: involvement in cellular imaging and in gene therapy against glioma

    NMR IN BIOMEDICINE, Issue 1 2010
    Anne-Karine Bouzier-Sore
    Abstract In gene therapy against glioma, targeting tumoral tissue is not an easy task. We used the tumor infiltrating property of microglia in this study. These cells are well adapted to this therapy since they can phagocyte nanoparticles and allow their visualization by MRI. Indeed, while many studies have used transfected microglia containing a suicide gene and other internalized nanoparticles to visualize microglia, none have combined both approaches during gene therapy. Microglia cells were transfected with the TK-GFP gene under the control of the HSP70 promoter. First, the possible cellular stress induced by nanoparticle internalization was checked to avoid a non-specific activation of the suicide gene. Then, MR images were obtained on tubes containing microglia loaded with superparamagnetic nanoparticles (VUSPIO) to characterize their MR properties, as well as their potential to track cells in vivo. VUSPIO were efficiently internalized by microglia, were found non-toxic and their internalization did not induce any cellular stress. VUSPIO relaxivity r2 was 224,mM,1.s,1. Such results could generate a very high contrast between loaded and unloaded cells on T2 -weighted images. The intracellular presence of VUSPIO does not prevent suicide gene activity, since TK is expressed in vitro and functional in vivo. It allows MRI detection of gene modified macrophages during cell therapy strategies. Copyright © 2009 John Wiley & Sons, Ltd. [source]

    Female-Specific Education, Management, and Lifestyle Enhancement for Implantable Cardioverter Defibrillator Patients: The FEMALE-ICD Study

    Background:,Significant rates of psychological distress occur in implantable cardioverter defibrillator (ICD) patients. Research has demonstrated that women are particularly at risk for developing distress and warrant psychosocial attention. The major objectives were to implement and test the effectiveness of a female-specific psychosocial group intervention on disease-specific quality of life outcomes in outpatient female ICD recipients versus a wait-list control group. Method:,Twenty-nine women were recruited for the study. Fourteen women were randomized to the intervention group and participated in a psychosocial intervention focused on female-specific issues; 15 were randomized to the wait-list control group. All women completed individual psychological batteries at baseline and at 1-month follow-up measuring shock anxiety and device acceptance. Results:,Pre-post measures of shock anxiety demonstrated a significant time by group interaction effect with the intervention group having a significantly greater decrease (Pillai's trace = 5.58, P = 0.026). A significant interaction effect (Pillai's trace = 5.05, P = 0.046) was found, such that women under the age of 50 experienced greater reduction in shock anxiety than their middle-aged cohorts. Pre-post measures of device acceptance revealed a significant time by group interaction effect with the intervention group having significantly greater increases (Pillai's trace = 5.80, P = 0.023). Conclusions:,Structured interventions for female ICD patients involving ICD-specific education, cognitive behavioral therapy strategies, and group social support provide improvements in shock anxiety and device acceptance at 1-month re-assessment. Young women appear to be an at-risk subgroup of this population and may experience more benefit from psychosocial treatment targeting device-specific concerns. (PACE 2010; 33:1131,1140) [source]

    A comparative analysis of constitutive and cell-specific promoters in the adult mouse hippocampus using lentivirus vector-mediated gene transfer

    Hitoshi Kuroda
    Abstract Background Viral vectors provide powerful tools for transgene delivery to the mammalian brain to assess the effects of therapeutic proteins, antisense RNAs or small interfering RNAs. A key advantage of such approaches is that specific brain regions implicated in a particular disease can be independently targeted. Methods To optimize transgene expression in sub-regions of the mouse hippocampus and with a view towards devising gene therapy strategies for Alzheimer's disease, we designed lentivirus-based reporter vectors bearing various promoters, including constitutive and cell-specific promoters. Furthermore, we devised methods allowing a side-by-side comparison of transgene expression levels in neural cells both in vitro and in vivo. Results Following stereotaxic injection into the adult mouse hippocampus, titer-adjusted lentiviral vectors bearing constitutive promoters resulted in robust and sub-region-specific transgene expression. Our results show that the human CMV-IE promoter resulted in efficient transgene expression in the entire hippocampus whereas transgene expression mediated by the hybrid hEF1,/HTLV promoter was limited mainly in the dentate gyrus and the CA2/3 region. Finally, the neuron-specific human synapsin I promoter was particularly effective in the dentate gyrus. Conclusions These findings indicate that subregion-specific transgene expression in the hippocampus can be achieved following lentivirus vector-mediated gene transfer. Copyright © 2008 John Wiley & Sons, Ltd. [source]

    p53 is dispensable for the induction of apoptosis after inhibition of protein kinase CK2

    THE PROSTATE, Issue 2 2010
    Carolin C. Schneider
    Abstract BACKGROUND Protein kinase CK2 is a ubiquitously expressed heterotetramer consisting of two catalytic ,/,, and two regulatory , subunits. Expression of CK2 is highly elevated in tumor cells where it protects cells from apoptosis. A variety of different compounds were tested as inhibitors of protein kinase CK2 in order to find new therapy strategies. To analyze the role of p53 in the response to CK2 inhibition we used one of the most specific CK2 inhibitors available, TBB, in different prostate cancer cell lines. METHODS We treated prostate cancer cells with the CK2 inhibitor TBB and determined its effect on CK2 activity by an in vitro phosphorylation assay and its effect on viability by an MTT assay. Furthermore, we analyzed changes in the expression of p53 and PARP cleavage by Western Blot analysis. RESULTS Inhibition of CK2 by TBB led to a decrease in cell viability and apoptosis in two cell lines which express wild-type p53 whereas two other cell lines expressing mutant or no p53 failed to show signs of apoptosis. Moreover, cell lines expressing wild-type p53 showed an increase of the amount of p53 and of its transactivation efficiency. However, down-regulation of p53 by RNAi showed that p53 is not necessary for the induction of apoptosis. CONCLUSIONS Wild-type p53 is not necessary for the induction of apoptosis by TBB in prostate cancer cells. Prostate 70: 126,134, 2010. ©2009 Wiley-Liss, Inc. [source]

    Exact Tests using Two Correlated Binomial Variables in Contemporary Cancer Clinical Trials

    Jihnhee Yu
    Abstract New therapy strategies for the treatment of cancer are rapidly emerging because of recent technology advances in genetics and molecular biology. Although newer targeted therapies can improve survival without measurable changes in tumor size, clinical trial conduct has remained nearly unchanged. When potentially efficacious therapies are tested, current clinical trial design and analysis methods may not be suitable for detecting therapeutic effects. We propose an exact method with respect to testing cytostatic cancer treatment using correlated bivariate binomial random variables to simultaneously assess two primary outcomes. The method is easy to implement. It does not increase the sample size over that of the univariate exact test and in most cases reduces the sample size required. Sample size calculations are provided for selected designs. [source]

    Tapetoretinal degenerations: Experiences, experiments and expectations

    Berndt Ehinger
    ABSTRACT. Tapetoretinal degenerations are a common cause for vision problems, but have until recently not been amenable to rational treatment. With rapidly increasing insights into basic neurobiology and pathobiology this has now begun to change. From having been a relatively small group of largely unknown yet fairly prevalent disorders, they are rapidly forming a large set of well defined diseases, and it is easy to predict that our knowledge about them will continue to increase for many years to come. Vitamin A (15 ,000 IU daily) is currently the only rational treatment available. However, in experimental animals, therapy strategies are now actively being developed along several different lines. Apoptotic photoreceptor cell death can be delayed with different drugs, and at least one of them, diltiazem, is approved for human use in cardiovascular diseases. It remains to be seen if it has any clinically significant effect in human tapetoretinal degenerations. Other strategies aim at counteracting the production of harmful protein variants, acting either on DNA or mRNA levels. Transgenes can also be used to induce the production of important but missing metabolic components. Finally, cells or retina sheets can be transplanted, either to replace failing cells or as a source for missing trophic factors. Neither of these strategies has yet been transferred to humans, but trials are under way. With the high increase in the flow of new information on tapetoretinal disorders, much more precise diagnoses and much improved treatments are soon to be expected, augmenting considerably the possibilities for ophthalmologists to help patients with such diseases. It is not likely that there will be a single treatment for all the many varieties. Instead, we are most likely going to see pharmacological treatments for some of them, DNA transfers for some, and transplantations for others. [source]

    New strategies for cancer gene therapy: Progress and opportunities

    2nd Australia, China Biomedical Research Conference (ACBRC2009)
    Summary 1.,To date, cancer persists as one of the most devastating diseases worldwide. Problems such as metastasis and tumour resistance to chemotherapy and radiotherapy have seriously limited the therapeutic effects of existing clinical treatments. 2.,To address these problems, cancer gene therapy has been developing over the past two decades, specifically designed to deliver therapeutic genes to treat cancers using vector systems. So far, a number of genes and delivery vehicles have been evaluated and significant progress has been made with several gene therapy modalities in clinical trials. However, the lack of an ideal gene delivery system remains a major obstacle for the successful translation of regimen to the clinic. 3.,Recent understanding of hypoxic and necrotic regions within solid tumours and rapid development of recombinant DNA technology have reignited the idea of using anaerobic bacteria as novel gene delivery systems. These bacterial vectors have unique advantages over other delivery systems and are likely to become the vector of choice for cancer gene therapy in the near future. 4.,Meanwhile, complicated tumour pathophysiology and associated metastasis make it hard to rely on a single therapeutic modality for complete tumour eradication. Therefore, the combination of cancer gene therapy with other conventional treatments has become paramount. 5.,The present review introduces important cancer gene therapy strategies and major vector systems that have been studied so far with an emphasis on bacteria-mediated cancer gene therapy. In addition, exemplary combined therapies are briefly reviewed. [source]

    Low-dose azathioprine or mercaptopurine in combination with allopurinol can bypass many adverse drug reactions in patients with inflammatory bowel disease

    Aliment Pharmacol Ther,31, 640,647 Summary Background, The thiopurine drugs, azathioprine and mercaptopurine (MP), are established treatments for IBD. However, therapeutic failure caused by adverse drug reactions occurs frequently. Aim, To study combination of allopurinol with reduced-dose thiopurine in an attempt to avoid adverse drug reactions in the treatment of IBD. Methods, Patients with drug reactions to full-dose thiopurines were recruited for combination therapy in two IBD centres in this retrospective study. Dosing was guided by measuring thiopurine methyltransferase (for UK patients) or thioguanine nucleotides and methyl-6MP (Australian patients). Response was monitored by clinical activity indices. Results, Of 41 patients, 25 had non-hepatic and 16 had hepatitic reactions. Clinical remission was achieved in 32 patients (78%) with a median follow-up of 41 weeks (range 0.5,400). Patients who did not respond to combination therapy tended to fail early with the same adverse reaction. The relative risk of having an adverse reaction with methyl-6MP in the top interquartile range was 2.7 (1.3,28) times that with methyl-6MP in the lower three quartiles (95% confidence interval). Conclusion, The combined experience from our centres is the largest reported experience of this combination therapy strategy in IBD, and the first to provide evidence for benefit in thiopurine and allopurinol co-therapy to avoid non-hepatitic adverse drug reactions. [source]

    Retroviral-based gene therapy with cyclooxygenase-2 promotes the union of bony callus tissues and accelerates fracture healing in the rat

    Charles H. Rundle
    Abstract Background An in vivo gene therapy strategy was developed to accelerate bone fracture repair. Methods Direct injection of a murine leukemia virus-based vector targeted transgene expression to the proliferating periosteal cells arising shortly after fracture. Cyclooxygenase-2 (Cox-2) was selected because the transgene for its prostaglandin products that promote angiogenesis, bone formation and bone resorption, are all required for fracture healing. The human (h) Cox-2 transgene was modified to remove AU-rich elements in the 3,-untranslated region and to improve protein translation. Results In vitro studies revealed robust and sustained Cox-2 protein expression, prostaglandin E2 and alkaline phosphatase production in rat bone marrow stromal cells and osteoblasts transgenic for the hCox-2 gene. In vivo studies in the rat femur fracture revealed that Cox-2 transgene expression produced bony union of the fracture by 21 days post-fracture, a time when cartilage persisted within the fracture tissues of control animals and approximately 1 week earlier than the healing normally observed in this model. None of the ectopic bone formation associated with bone morphogenetic protein gene therapy was observed. Conclusions This study represents the first demonstration that a single local application of a retroviral vector expressing a single osteoinductive transgene consistently accelerated fracture repair. Copyright © 2007 John Wiley & Sons, Ltd. [source]

    RD114-pseudotyped retroviral vectors kill cancer cells by syncytium formation and enhance the cytotoxic effect of the TK/GCV gene therapy strategy

    E. Germain
    Abstract Background Wild-type RD114 virus is capable of generating syncytia during its replication, and it is believed that cell-free viruses direct the fusion of neighboring cells. The RD114 envelope (Env) that mediates this fusion event is now widely used to pseudotype retroviral and lentiviral vectors in gene therapy. Indeed, vectors pseudotyped with RD114 Env are very efficient to transfer genes into human hematopoietic cells, and they are resistant to human complement inactivation. In this study, we have tested the potential of RD114-pseudotyped vectors produced from the FLYRD18 packaging cell line to induce syncytia. Methods RD114-pseudotyped vectors produced from the FLYRD18 packaging cells were added on tumor cell lines, and the formation of syncytia was assessed by microscopy after cell fixation and methylene blue staining. The kinetics of syncytium formation was analyzed by time-lapse microscopy. Finally, the cytotoxic effect of RD114-pseudotyped vectors was measured by the MTT assay on tumor cells, and in combination with the TK/GCV strategy. Results We have found that these vectors were able to mediate cell-to-cell fusion of human tumor cell lines. A few hours after addition of the vector, cells started to aggregate to form syncytia that eventually evolved toward cell death 48 h postinfection. RD114-pseudotyped vectors were very efficient at killing human cancer cells, and they were also able to enhance dramatically the cytotoxic effect of the TK/GCV strategy. Conclusions These findings indicate that RD114-pseudotyped vectors used alone, or in combination with a suicide gene therapy approach, have great potential for the treatment of cancer. Copyright © 2004 John Wiley & Sons, Ltd. [source]

    An efficient targeted radiotherapy/gene therapy strategy utilising human telomerase promoters and radioastatine and harnessing radiation-mediated bystander effects

    Marie Boyd
    Abstract Background Targeted radiotherapy achieves malignant cell-specific concentration of radiation dosage by tumour-affinic molecules conjugated to radioactive atoms. Combining gene therapy with targeted radiotherapy is attractive because the associated cross-fire irradiation of the latter induces biological bystander effects upon neighbouring cells overcoming low gene transfer efficiency. Methods We sought to maximise the tumour specificity and efficacy of noradrenaline transporter (NAT) gene transfer combined with treatment using the radiopharmaceutical meta-[131I]iodobenzylguanidine ([131I]MIBG). Cell-kill was achieved by treatment with the ,-decay particle emitter [131I]MIBG or the ,-particle emitter [211At]MABG. We utilised our novel transfected mosaic spheroid model (TMS) to determine whether this treatment strategy could result in sterilisation of spheroids containing only a small proportion of NAT-expressing cells. Results The concentrations of [131I]MIBG and [211At]MABG required to reduce to 0.1% the survival of clonogens derived from the TMS composed of 100% of NAT gene-transfected cells were 1.5 and 0.004 MBq/ml (RSV promoter), 8.5 and 0.0075 MBq/ml (hTR promoter), and 9.0 and 0.008 MBq/ml (hTERT promoter), respectively. The concentrations of radiopharmaceutical required to reduce to 0.1% the survival of clonogens derived from 5% RSV/NAT and 5% hTERT/NAT TMS were 14 and 23 MBq/ml, respectively, for treatment with [131I]MIBG and 0.018 and 0.028 MBq/ml, respectively, for treatment with [211At]MABG. Conclusions These results indicate that the telomerase promoters have the capacity to drive the expression of the NAT. The potency of [211At]MABG is approximately three orders of magnitude greater than that of [131I]MIBG. Spheroids composed of only 5% of cells expressing NAT under the control of the RSV or hTERT promoter were sterilised by radiopharmaceutical treatment. This observation is indicative of bystander cell-kill. Copyright © 2004 John Wiley & Sons, Ltd. [source]

    Gene Therapy for Head and Neck Cancer ,

    THE LARYNGOSCOPE, Issue 5 2000
    Lyon L. Gleich MD
    Abstract Objectives/Hypothesis New treatment methods are needed for head and neck cancer to improve survival without increasing morbidity. Gene therapy is a potential method of improving patient outcome. Progress in gene therapy for cancer is reviewed with emphasis on the limitations of vector technology and treatment strategies. Given the current technological vector limitations in transmitting the therapeutic genes, treatments that require the fewest number of cells to be altered by the new gene are optimal. Therefore an immune-based gene therapy strategy was selected in which the tumors were transfected with the gene for an alloantigen, human leukocyte antigen (HLA),B7, a class I major histocompatibility complex (MHC). This would restore an antigen presentation mechanism in the tumor to induce an antitumor response. This gene therapy strategy was tested in patients with advanced, unresectable head and neck cancer. Study Design Prospective trial. Methods Twenty patients with advanced head and neck cancer who had failed conventional therapy and did not e-press HLA-B7 were treated with gene therapy using a lipid vector by direct intratumoral injection. The gene therapy product contained the HLA-B7 gene and the ,2-microglobulin gene, which permits complete e-pression of the class I MHC at the cell surface. Patients were assessed for any adverse effects, for changes in tumor size, for time to disease progression, and for survival. Biopsy specimens were assessed for pathological response, HLA-B7 e-pression, apoptosis, cellular proliferation, CD-8 cells, granzyme, and p53 status. Results There were no adverse effects from the gene therapy. At 16 weeks after beginning gene therapy, four patients had a partial response and two patients had stable disease. Two of the tumors completely responded clinically, but tumor was still seen on pathological examination. The time to disease progression in the responding patients was 20 to 80 weeks. The median survival in patients who completed gene therapy was 54 weeks, compared with 21 weeks in patients whose tumors progressed after the first cycle of treatment. One patient survived for 106 weeks without any additional therapy. HLA-B7 was demonstrated in the treated tumors, and increased apoptosis was seen in the responding tumors. Conclusion Significant advances have been made in the field of gene therapy for cancer. Alloantigen gene therapy has had efficacy in the treatment of cancer and can induce tumor responses in head and neck tumors. Alloantigen gene therapy has significant potential as an adjunctive treatment of head and neck cancer. [source]

    NF-,B as a potential molecular target for cancer therapy

    BIOFACTORS, Issue 1 2007
    Chae Hyeong Lee
    Abstract Nuclear factor ,B (NF-,B), a transcription factor, plays an important role in carcinogenesis as well as in the regulation of immune and inflammatory responses. NF-,B induces the expression of diverse target genes that promote cell proliferation, regulate apoptosis, facilitate angiogenesis and stimulate invasion and metastasis. Furthermore, many cancer cells show aberrant or constitutive NF-,B activation which mediates resistance to chemo- and radio-therapy. Therefore, the inhibition of NF-,B activation and its signaling pathway offers a potential cancer therapy strategy. In addition, recent studies have shown that NF-,B can also play a tumor suppressor role in certain settings. In this review, we focus on the role of NF-,B in carcinogenesis and the therapeutic potential of targeting NF-,B in cancer therapy. [source]

    Enzymatic stability of 2,-ethylcarbonate-linked paclitaxel in serum and conversion to paclitaxel by rabbit liver carboxylesterase for use in prodrug/enzyme therapy

    Tadatoshi Tanino
    Abstract In prodrug/enzyme therapy for cancer, information on the sensitivity of hydrolytic enzymes to prodrug is required to reduce adverse effects of the parental drug and to find the activating enzyme. The aim of this study was to characterize the enzymatic stability of 2,-ethylcarbonate-linked paclitaxel (TAX-2,-Et) in the sera of several different species including humans. TAX-2,-Et disposition in serum was kinetically analysed using models with hydrolytic and/or degradation processes. To further evaluate the capability of liver carboxylesterases (CESs) in TAX-2,-Et hydrolysis, a CES isolated from rabbit liver (Ra-CES) was utilized as a model enzyme. Rat serum provided rapid enzymatic hydrolysis of TAX-2,-Et with a half-life of 4 min. The degradation of paclitaxel (TAX) (degradation rate constant, 0.16,h,1) was accompanied by the formation of an unknown compound. The conversion to TAX was almost completely inhibited by phenylmethyl sulfonylfluoride (PMSF) and bis(p-nitrophenyl) phosphate (BNPP). In human and rabbit sera, the degradation rate constant of TAX-2,-Et was 5.1,×,10,2 and 0.15,h,1, respectively, when excepting hydrolysis. The degradation products had the same molecular weight as TAX-2,-Et. The amount of TAX produced accounted for only 8,11% of the decrease in TAX-2,-Et after a 9 h exposure to rabbit or human serum. PMSF, but not BNPP, inhibited more than 90% of the TAX production in a 1.5,h incubation with human or rabbit serum. Ra-CES enzyme converted TAX-2,-Et to TAX with Vmax and Km of 74.7±13.8 nmol/min/mg protein and 8.8±2.8 µM, respectively. These results indicate that TAX-2,-Et is sensitive to serum CESs, but not cholinesterases. However, serum CESs show species-dependent hydrolysis of TAX-2,-Et. Although human serum allows the slow release of TAX, TAX-2,-Et is expected to reduce the side-effects of TAX. The Ra-CES enzyme is capable of hydrolysing TAX-2,-Et, which may be beneficial for the development of a TAX-2,-Et/enzyme therapy strategy for ovarian cancer. Copyright © 2008 John Wiley & Sons, Ltd. [source]

    Biosynthesis of FVIII in megakaryocytic cells: improved production and biochemical characterization

    Marie-Hélène Rodriguez
    Summary Haemophilia A is an attractive target for gene therapy. We designed a haemophilia A gene therapy strategy involving the genetic modification of haematopoietic stem cells to achieve tissue-specific expression of a factor VIII (FVIII) transgene in the megakaryocytic lineage. Platelets would then serve as vehicles to store the expressed FVIII and deliver the coagulation factor at the site of vascular injury. A local correction of the haemostasis defect could, therefore, be expected following platelet activation and secretion. In this study, we demonstrated that a model of haematopoietic cell lines (Dami cells) could produce a correctly processed FVIII. FVIII transgenes were placed under the control of the human platelet glycoprotein IIb (GPIIb) promoter and used for stable transfection of the Dami megakaryocytic cell line. The highest FVIII production was obtained when the FVIII transgene contained a factor IX intron 1 gene sequence inserted in the FVIII intron 1 and 13 sites. Reverse transcription polymerase chain reaction demonstrated that the splicing of these introns was complete. Recombinant FVIII (rFVIII) produced in Dami cells was a biologically active molecule (specific activity: 5664 IU/mg) that was correctly glycosylated and sulphated. This recombinant FVIII protein exhibited biochemical characteristics after deglycosylation or thrombin activation that were comparable to a commercially available B-domainless rFVIII. These results demonstrate the advantages of a modified FVIII transgene and represent the first biochemical characterization of megakaryocyte-produced FVIII. [source]

    Development of lentiviral vectors for gene therapy for Usher syndrome type 1B

    Purpose: Usher 1B, one of the major subtypes of a combined blindness and deafness disease, is caused by mutations in the MYO7A gene, which encodes a large unconventional myosin expressed in the retinal pigment epithelium (RPE) and photoreceptor (PR) cells. This study aims at developing viral vectors expressing the wild type human MYO7A at an adequate level in order to rescue cellular phenotypes of MYO7A mutation. Methods: The full-length (7 kb) human MYO7A cDNA was cloned into the third generation, self-inactivating lentiviral vector under different promoters and enhancers. Human genomic 4-kb DNA fragment including exon 1 through 2 was cloned by PCR. Activities of different promoters and enhancers were tested by reporter assays using ARPE-19 cells. Previously identified Myo7a-null phenotypes in shaker-1 mouse were used to test the efficacy of various lentiviruses. Results: Lentiviral vectors could successfully transduce large genes (up to 7.6 kb) in vitro and in vivo for the purpose of gene therapy. Reporter assay indicated that regions with a suppressor activity and an enhancer activity existed within intron 1. The CMV promoter drove excessive MYO7A expression in the RPE, and thus caused cell death. A chimeric promoter that consists of partial CMV promoter with 160-bp MYO7A enhancer could direct moderate levels of gene expression in RPE and PR in vivo, and rescued a number of phenotypes in the mutant mice. Conclusions: These results illustrate the importance of regulating transgene expression levels in achieving therapeutic outcomes. They demonstrate the efficacy of lentivirus-mediated expression of the large MYO7A cDNA as a gene therapy strategy for correcting the MYO7A deficiency underlying Usher 1B. [source]