The Experts below are selected from a list of 6312 Experts worldwide ranked by ideXlab platform
Lourdes R. Desviat - One of the best experts on this subject based on the ideXlab platform.
-
Antisense Mediated Splicing Modulation For Inherited Metabolic Diseases: Challenges for Delivery
Nucleic acid therapeutics, 2014Co-Authors: Belén Pérez, Luisa Vilageliu, Daniel Grinberg, Lourdes R. DesviatAbstract:In the past few years, research in targeted mutation therapies has experienced significant advances, especially in the field of rare diseases. In particular, the efficacy of Antisense Therapy for suppression of normal, pathogenic, or cryptic splice sites has been demonstrated in cellular and animal models and has already reached the clinical trials phase for Duchenne muscular dystrophy. In different inherited metabolic diseases, splice switching oligonucleotides (SSOs) have been used with success in patients' cells to force pseudoexon skipping or to block cryptic splice sites, in both cases recovering normal transcript and protein and correcting the enzyme deficiency. However, future in vivo studies require individual approaches for delivery depending on the gene defect involved, given the different patterns of tissue and organ expression. Herein we review the state of the art of Antisense Therapy targeting RNA splicing in metabolic diseases, grouped according to their expression patterns—multisystemic, h...
-
Pseudoexon exclusion by Antisense Therapy in 6-pyruvoyl-tetrahydropterin synthase deficiency.
Human mutation, 2011Co-Authors: Sandra Brasil, Belén Pérez, Magdalena Ugarte, Lourdes R. Desviat, Hiu Man Viecelli, David Meili, Anahita Rassi, Beat ThönyAbstract:Antisense oligonucleotide Therapy to modulate splicing mutations in inherited diseases is emerging as a treatment option also for metabolic defects. In this article, we report the effect of cellular Antisense Therapy to suppress pseudoexon activation in primary dermal fibroblasts from patients with mutations in the PTS gene encoding 6-pyruvoyltetrahydropterin synthase (PTPS), which leads to tetrahydrobiopterin and monoamine neurotransmitter deficiency. Pathogenic inclusion of SINE or LINE-derived cryptic exons in different PTPS patients due to the intronic mutations c.84-322A>T, c.163 + 695_163 + 751del57, or c.164-712A>T was demonstrated by transcript analysis in fibroblasts and minigene ex vivo assays. Antisense morpholino oligonucleotides (AMOs) directed to the pseudoexons 3' or 5' splice sites were designed with the aim of preventing the pathological pseudoexon inclusion. At the time of AMO transfection, we investigated patients' cells for correct PTS-mRNA splicing and functional recovery of the PTPS protein. Transcriptional profiling after 24 hr posttransfection revealed a dose- and sequence-specific recovery of normal splicing. Furthermore, PTPS enzyme activity in all three patients' fibroblasts and the pterin profile were close to normal values after Antisense treatment. Our results demonstrate proof-of-concept for pseudoexon exclusion Therapy using AMO in inherited metabolic disease. Hum Mutat 32:1-9, 2011. © 2011 Wiley-Liss, Inc.
-
Present and future of Antisense Therapy for splicing modulation in inherited metabolic disease
Journal of Inherited Metabolic Disease, 2010Co-Authors: Belén Pérez, Magdalena Ugarte, Laura Rodríguez-pascau, Luisa Vilageliu, Daniel Grinberg, Lourdes R. DesviatAbstract:The number of mutations identified deep in introns which activate or create novel splice sites resulting in pathogenic pseudoexon inclusion in mRNA continues to grow for inherited metabolic disease (IMD) and other human genetic diseases. A common characteristic is that the native splice sites remain intact thus retaining the potential for normal splicing. Antisense oligonucleotides (AO) have been shown to modulate the splicing pattern by steric hindrance of the recognition and binding of the splicing apparatus to the selected sequences. In the case of pseudoexons, AO force the use of the natural splice sites, recovering normally spliced transcripts encoding functional protein. This review summarizes the present knowledge of Antisense splicing modulation as a molecular Therapy approach for pseudoexon-activating mutations, with a focus in IMD. Although the feasibility of treatment for patients with IMD has yet to be proven, it appears to be clinically promising, as positive results have been reported in cellular and animal models of disease, and Antisense Therapy for splicing modulation is currently in the clinical trials phase for Duchenne muscular dystrophy patients. Here, we review the most recent advances in AO stability, targeting and delivery, and other issues to be considered for an effective treatment in the clinical setting. Although the number of patients who can be potentially treated is low for each IMD, it represents an excellent therapeutical option as a type of personalized molecular medicine which is especially relevant for diseases for which there is, to date, no efficient treatment.
-
Pseudoexon exclusion by Antisense Therapy in methylmalonic aciduria (MMAuria).
Human mutation, 2009Co-Authors: Belén Pérez, Ana Rincón, Ana Jorge-finnigan, Eva Richard, B. Merinero, Magdalena Ugarte, Lourdes R. DesviatAbstract:Development of pseudoexon exclusion therapies by Antisense modification of pre-mRNA splicing represents a type of personalized genetic medicine. Here we present the cellular Antisense Therapy and the cell-based splicing assays to investigate the effect of two novel deep intronic changes c.1957–898A>G and c.1957–920C>A identified in the methylmalonyl–coenzyme A (CoA) mutase (MUT) gene. The results show that the nucleotide change c.1957–898A>G is a pathological mutation activating pseudoexon insertion and that Antisense morpholino oligonucleotide (AMO) treatment in patient fibroblasts leads to recovery of MUT activity to levels 25 to 100% of control range. On the contrary, the change c.1957–920C>A, identified in two fibroblasts cell lines in cis with c.1885A>G (p.R629G) or c.458T>A (p.D153V), appears to be a rare variant of uncertain clinical significance. The functional analysis of c.1885A>G and c.458T>A indicate that they are the disease-causing mutations in these two patients. The results presented here highlight the necessity of scanning the described intronic region for mutations in MUT-affected patients, followed by functional analyses to demonstrate the pathogenicity of the identified changes, and extend previous work of the applicability of the Antisense approach in methylmalonic aciduria (MMAuria) for a novel intronic mutation. Hum Mutat 30:1–7, 2009. © 2009 Wiley-Liss, Inc.
Burkhard Jansen - One of the best experts on this subject based on the ideXlab platform.
-
Antisense Therapy for cancer the time of truth
Lancet Oncology, 2002Co-Authors: Burkhard Jansen, Uwe ZangemeisterwittkeAbstract:Summary The recent acceleration in the identification and characterisation of new molecular targets for cancer and the limited effectiveness of conventional treatment strategies has focused considerable interest on the development of new types of anticancer agents. These new drugs are hoped to be highly specific for malignant cells with a favorable side-effect profile due to well-defined mechanisms of action. Antisense oligonucleotides are one such class of new agent-they are short, synthetic stretches of DNA which hybridise with specific mRNA strands that correspond to target genes. By binding to the mRNA, the Antisense oligonucleotides prevent the sequence of the target gene being converted into a protein, thereby blocking the action of the gene. Several genes known to be important in the regulation of apoptosis, cell growth, metastasis, and angiogenesis, have been validated as molecular targets for Antisense Therapy. Furthermore, new targets are rapidly being uncovered through coordinated functional genomics and proteomics initiatives. Phosphorothioate oligonucleotides are the current gold standard for Antisense Therapy; they have acceptable physical and chemical properties and show reasonable resistance to nucleases. Recently, new generations of these phosphorothioate oligonucleotides that contain 2′-modified nucleoside building blocks to enhance RNA binding affinity and decrease indirect toxic effects have been developed. Antisense therapeutics are, after decades of difficulties, finally close to fulfilling their promise in the clinic.
-
Antisense Therapy for cancer—the time of truth
The Lancet. Oncology, 2002Co-Authors: Burkhard Jansen, Uwe Zangemeister-wittkeAbstract:Summary The recent acceleration in the identification and characterisation of new molecular targets for cancer and the limited effectiveness of conventional treatment strategies has focused considerable interest on the development of new types of anticancer agents. These new drugs are hoped to be highly specific for malignant cells with a favorable side-effect profile due to well-defined mechanisms of action. Antisense oligonucleotides are one such class of new agent-they are short, synthetic stretches of DNA which hybridise with specific mRNA strands that correspond to target genes. By binding to the mRNA, the Antisense oligonucleotides prevent the sequence of the target gene being converted into a protein, thereby blocking the action of the gene. Several genes known to be important in the regulation of apoptosis, cell growth, metastasis, and angiogenesis, have been validated as molecular targets for Antisense Therapy. Furthermore, new targets are rapidly being uncovered through coordinated functional genomics and proteomics initiatives. Phosphorothioate oligonucleotides are the current gold standard for Antisense Therapy; they have acceptable physical and chemical properties and show reasonable resistance to nucleases. Recently, new generations of these phosphorothioate oligonucleotides that contain 2′-modified nucleoside building blocks to enhance RNA binding affinity and decrease indirect toxic effects have been developed. Antisense therapeutics are, after decades of difficulties, finally close to fulfilling their promise in the clinic.
-
Antisense Therapy: current status in prostate cancer and other malignancies.
Cancer metastasis reviews, 2002Co-Authors: Martin E. Gleave, Uwe Zangemeister-wittke, Hideake Miyake, Burkhard JansenAbstract:Recent technological advances now allowing both large scale data generation and its in-depth analysis have opened new avenues to identify and target genes involved in neoplastic transformation and tumor progression. This accelerated identification and characterization of cancer-relevant molecular targets has sparked considerable interest in the development of new generations of anti-cancer agents. It is anticipated, that these agents will show enhanced specificity for malignant cells and a more favorable side-effect profile due to well-defined and tailored modes of action. Antisense oligonucleotides (ASOs) are short synthetic stretches of chemically modified DNA capable of specifically hybridizing to the mRNA of a chosen cancer-relevant target gene are close, after decades of challenges, close to fulfilling their promise in the clinical setting. Emerging clinical evidence supports the notion that ASOs stand a realistic chance of developing into one of the main players of rationally designed anti-cancer agents, although certainly not all of the challenges have been met to date. The status of Antisense targeting of genes relevant to prostate cancer, including bcl-2, bcl-xL, clusterin, androgen receptor (AR) and IGFBPs, are reviewed.
-
bcl 2 Antisense Therapy chemosensitizes human melanoma in scid mice
Nature Medicine, 1998Co-Authors: Burkhard Jansen, Klaus Wolff, Hermine Schlagbauerwadl, Bob D Brown, Robert N Bryan, Andrea Van Elsas, Markus Muller, Hansgeorg Eichler, Hubert PehambergerAbstract:Malignant melanoma is a prime example of cancers that respond poorly to various treatment modalities including chemoTherapy1. A number of chemotherapeutic agents have been shown recently to act by inducing apoptosis, a type of cell death antagonized by the bcl-2 gene2. Human melanoma expresses Bcl-2 in up to 90% of all cases3–7. In the present study we demonstrate that bcl-2 Antisense oligonucleotide treatment improves the chemo-sensitivity of human melanoma grown in severe combined im-munodeficient (SCID) mice. Our findings suggest that reduction of Bcl-2 in melanoma, and possibly also in a variety of other tumors, may be a novel and rational approach to improve chemosensitivity and treatment outcome.
Belén Pérez - One of the best experts on this subject based on the ideXlab platform.
-
Antisense Mediated Splicing Modulation For Inherited Metabolic Diseases: Challenges for Delivery
Nucleic acid therapeutics, 2014Co-Authors: Belén Pérez, Luisa Vilageliu, Daniel Grinberg, Lourdes R. DesviatAbstract:In the past few years, research in targeted mutation therapies has experienced significant advances, especially in the field of rare diseases. In particular, the efficacy of Antisense Therapy for suppression of normal, pathogenic, or cryptic splice sites has been demonstrated in cellular and animal models and has already reached the clinical trials phase for Duchenne muscular dystrophy. In different inherited metabolic diseases, splice switching oligonucleotides (SSOs) have been used with success in patients' cells to force pseudoexon skipping or to block cryptic splice sites, in both cases recovering normal transcript and protein and correcting the enzyme deficiency. However, future in vivo studies require individual approaches for delivery depending on the gene defect involved, given the different patterns of tissue and organ expression. Herein we review the state of the art of Antisense Therapy targeting RNA splicing in metabolic diseases, grouped according to their expression patterns—multisystemic, h...
-
clinical biochemical and molecular studies in pyridoxine dependent epilepsy Antisense Therapy as possible new therapeutic option
Epilepsia, 2013Co-Authors: Belén Pérez, Luis Gonzalez Gutierrezsolana, Alfonso Verdu, Begona Merinero, Patricia Yustecheca, Pedro Ruizsala, Rocio Calvo, Anil Jalan, Laura Lopez Marin, Oscar CamposAbstract:Summary Purpose Pyridoxine-dependent epilepsy seizure (PDE; OMIM 266100) is a disorder associated with severe seizures that can be controlled pharmacologically with pyridoxine. In the majority of patients with PDE, the disorder is caused by the deficient activity of the enzyme α-aminoadipic semialdehyde dehydrogenase (antiquitin protein), which is encoded by the ALDH7A1 gene. The aim of this work was the clinical, biochemical, and genetic analysis of 12 unrelated patients, mostly from Spain, in an attempt to provide further valuable data regarding the wide clinical, biochemical, and genetic spectrum of the disease. Methods The disease was confirmed based on the presence of α-aminoadipic semialdehyde (α-AASA) in urine measured by liquid chromatography tandem mass spectrometry (LC-MS/MS) and pipecolic acid (PA) in plasma and/or cerebrospinal fluid (CSF) measured by high performance liquid chromatography (HPLC)/MS/MS and by sequencing analysis of messenger RNA (mRNA) and genomic DNA of ALDH7A1. Key Findings Most of the patients had seizures in the neonatal period, but they responded to vitamin B6 administration. Three patients developed late-onset seizures, and most patients showed mild-to-moderate postnatal developmental delay. All patients had elevated PA and α-AASA levels, even those who had undergone pyridoxine treatment for several years. The clinical spectrum of our patients is not limited to seizures but many of them show associated neurologic dysfunctions such as muscle tone alterations, irritability, and psychomotor retardation. The mutational spectrum of the present patients included 12 mutations, five already reported (c.500A>G, c.919C>T, c.1429G>C c.1217_1218delAT, and c.1482-1G>T) and seven novel sequence changes (c.75C>T, c.319G>T, c.554_555delAA, c.757C>T, c.787 + 1G>T, c.1474T>C, c.1093-?_1620+?). Only one mutation, p.G477R (c.1429G>C), was recurrent; this was detected in four different alleles. Transcriptional profile analysis of one patient's lymphoblasts and ex vivo splicing analysis showed the silent nucleotide change c.75C>T to be a novel splicing mutation creating a new donor splice site inside exon 1. Antisense Therapy of the aberrant mRNA splicing in a lymphoblast cell line harboring mutation c.75C>T was successful. Significance The present results broaden our knowledge of PDE, provide information regarding the genetic background of PDE in Spain, afford data of use when making molecular-based prenatal diagnosis, and provide a cellular proof-of concept for Antisense Therapy application.
-
Pseudoexon exclusion by Antisense Therapy in 6-pyruvoyl-tetrahydropterin synthase deficiency.
Human mutation, 2011Co-Authors: Sandra Brasil, Belén Pérez, Magdalena Ugarte, Lourdes R. Desviat, Hiu Man Viecelli, David Meili, Anahita Rassi, Beat ThönyAbstract:Antisense oligonucleotide Therapy to modulate splicing mutations in inherited diseases is emerging as a treatment option also for metabolic defects. In this article, we report the effect of cellular Antisense Therapy to suppress pseudoexon activation in primary dermal fibroblasts from patients with mutations in the PTS gene encoding 6-pyruvoyltetrahydropterin synthase (PTPS), which leads to tetrahydrobiopterin and monoamine neurotransmitter deficiency. Pathogenic inclusion of SINE or LINE-derived cryptic exons in different PTPS patients due to the intronic mutations c.84-322A>T, c.163 + 695_163 + 751del57, or c.164-712A>T was demonstrated by transcript analysis in fibroblasts and minigene ex vivo assays. Antisense morpholino oligonucleotides (AMOs) directed to the pseudoexons 3' or 5' splice sites were designed with the aim of preventing the pathological pseudoexon inclusion. At the time of AMO transfection, we investigated patients' cells for correct PTS-mRNA splicing and functional recovery of the PTPS protein. Transcriptional profiling after 24 hr posttransfection revealed a dose- and sequence-specific recovery of normal splicing. Furthermore, PTPS enzyme activity in all three patients' fibroblasts and the pterin profile were close to normal values after Antisense treatment. Our results demonstrate proof-of-concept for pseudoexon exclusion Therapy using AMO in inherited metabolic disease. Hum Mutat 32:1-9, 2011. © 2011 Wiley-Liss, Inc.
-
Present and future of Antisense Therapy for splicing modulation in inherited metabolic disease
Journal of Inherited Metabolic Disease, 2010Co-Authors: Belén Pérez, Magdalena Ugarte, Laura Rodríguez-pascau, Luisa Vilageliu, Daniel Grinberg, Lourdes R. DesviatAbstract:The number of mutations identified deep in introns which activate or create novel splice sites resulting in pathogenic pseudoexon inclusion in mRNA continues to grow for inherited metabolic disease (IMD) and other human genetic diseases. A common characteristic is that the native splice sites remain intact thus retaining the potential for normal splicing. Antisense oligonucleotides (AO) have been shown to modulate the splicing pattern by steric hindrance of the recognition and binding of the splicing apparatus to the selected sequences. In the case of pseudoexons, AO force the use of the natural splice sites, recovering normally spliced transcripts encoding functional protein. This review summarizes the present knowledge of Antisense splicing modulation as a molecular Therapy approach for pseudoexon-activating mutations, with a focus in IMD. Although the feasibility of treatment for patients with IMD has yet to be proven, it appears to be clinically promising, as positive results have been reported in cellular and animal models of disease, and Antisense Therapy for splicing modulation is currently in the clinical trials phase for Duchenne muscular dystrophy patients. Here, we review the most recent advances in AO stability, targeting and delivery, and other issues to be considered for an effective treatment in the clinical setting. Although the number of patients who can be potentially treated is low for each IMD, it represents an excellent therapeutical option as a type of personalized molecular medicine which is especially relevant for diseases for which there is, to date, no efficient treatment.
-
Pseudoexon exclusion by Antisense Therapy in methylmalonic aciduria (MMAuria).
Human mutation, 2009Co-Authors: Belén Pérez, Ana Rincón, Ana Jorge-finnigan, Eva Richard, B. Merinero, Magdalena Ugarte, Lourdes R. DesviatAbstract:Development of pseudoexon exclusion therapies by Antisense modification of pre-mRNA splicing represents a type of personalized genetic medicine. Here we present the cellular Antisense Therapy and the cell-based splicing assays to investigate the effect of two novel deep intronic changes c.1957–898A>G and c.1957–920C>A identified in the methylmalonyl–coenzyme A (CoA) mutase (MUT) gene. The results show that the nucleotide change c.1957–898A>G is a pathological mutation activating pseudoexon insertion and that Antisense morpholino oligonucleotide (AMO) treatment in patient fibroblasts leads to recovery of MUT activity to levels 25 to 100% of control range. On the contrary, the change c.1957–920C>A, identified in two fibroblasts cell lines in cis with c.1885A>G (p.R629G) or c.458T>A (p.D153V), appears to be a rare variant of uncertain clinical significance. The functional analysis of c.1885A>G and c.458T>A indicate that they are the disease-causing mutations in these two patients. The results presented here highlight the necessity of scanning the described intronic region for mutations in MUT-affected patients, followed by functional analyses to demonstrate the pathogenicity of the identified changes, and extend previous work of the applicability of the Antisense approach in methylmalonic aciduria (MMAuria) for a novel intronic mutation. Hum Mutat 30:1–7, 2009. © 2009 Wiley-Liss, Inc.
Magdalena Ugarte - One of the best experts on this subject based on the ideXlab platform.
-
Pseudoexon exclusion by Antisense Therapy in 6-pyruvoyl-tetrahydropterin synthase deficiency.
Human mutation, 2011Co-Authors: Sandra Brasil, Belén Pérez, Magdalena Ugarte, Lourdes R. Desviat, Hiu Man Viecelli, David Meili, Anahita Rassi, Beat ThönyAbstract:Antisense oligonucleotide Therapy to modulate splicing mutations in inherited diseases is emerging as a treatment option also for metabolic defects. In this article, we report the effect of cellular Antisense Therapy to suppress pseudoexon activation in primary dermal fibroblasts from patients with mutations in the PTS gene encoding 6-pyruvoyltetrahydropterin synthase (PTPS), which leads to tetrahydrobiopterin and monoamine neurotransmitter deficiency. Pathogenic inclusion of SINE or LINE-derived cryptic exons in different PTPS patients due to the intronic mutations c.84-322A>T, c.163 + 695_163 + 751del57, or c.164-712A>T was demonstrated by transcript analysis in fibroblasts and minigene ex vivo assays. Antisense morpholino oligonucleotides (AMOs) directed to the pseudoexons 3' or 5' splice sites were designed with the aim of preventing the pathological pseudoexon inclusion. At the time of AMO transfection, we investigated patients' cells for correct PTS-mRNA splicing and functional recovery of the PTPS protein. Transcriptional profiling after 24 hr posttransfection revealed a dose- and sequence-specific recovery of normal splicing. Furthermore, PTPS enzyme activity in all three patients' fibroblasts and the pterin profile were close to normal values after Antisense treatment. Our results demonstrate proof-of-concept for pseudoexon exclusion Therapy using AMO in inherited metabolic disease. Hum Mutat 32:1-9, 2011. © 2011 Wiley-Liss, Inc.
-
Present and future of Antisense Therapy for splicing modulation in inherited metabolic disease
Journal of Inherited Metabolic Disease, 2010Co-Authors: Belén Pérez, Magdalena Ugarte, Laura Rodríguez-pascau, Luisa Vilageliu, Daniel Grinberg, Lourdes R. DesviatAbstract:The number of mutations identified deep in introns which activate or create novel splice sites resulting in pathogenic pseudoexon inclusion in mRNA continues to grow for inherited metabolic disease (IMD) and other human genetic diseases. A common characteristic is that the native splice sites remain intact thus retaining the potential for normal splicing. Antisense oligonucleotides (AO) have been shown to modulate the splicing pattern by steric hindrance of the recognition and binding of the splicing apparatus to the selected sequences. In the case of pseudoexons, AO force the use of the natural splice sites, recovering normally spliced transcripts encoding functional protein. This review summarizes the present knowledge of Antisense splicing modulation as a molecular Therapy approach for pseudoexon-activating mutations, with a focus in IMD. Although the feasibility of treatment for patients with IMD has yet to be proven, it appears to be clinically promising, as positive results have been reported in cellular and animal models of disease, and Antisense Therapy for splicing modulation is currently in the clinical trials phase for Duchenne muscular dystrophy patients. Here, we review the most recent advances in AO stability, targeting and delivery, and other issues to be considered for an effective treatment in the clinical setting. Although the number of patients who can be potentially treated is low for each IMD, it represents an excellent therapeutical option as a type of personalized molecular medicine which is especially relevant for diseases for which there is, to date, no efficient treatment.
-
Pseudoexon exclusion by Antisense Therapy in methylmalonic aciduria (MMAuria).
Human mutation, 2009Co-Authors: Belén Pérez, Ana Rincón, Ana Jorge-finnigan, Eva Richard, B. Merinero, Magdalena Ugarte, Lourdes R. DesviatAbstract:Development of pseudoexon exclusion therapies by Antisense modification of pre-mRNA splicing represents a type of personalized genetic medicine. Here we present the cellular Antisense Therapy and the cell-based splicing assays to investigate the effect of two novel deep intronic changes c.1957–898A>G and c.1957–920C>A identified in the methylmalonyl–coenzyme A (CoA) mutase (MUT) gene. The results show that the nucleotide change c.1957–898A>G is a pathological mutation activating pseudoexon insertion and that Antisense morpholino oligonucleotide (AMO) treatment in patient fibroblasts leads to recovery of MUT activity to levels 25 to 100% of control range. On the contrary, the change c.1957–920C>A, identified in two fibroblasts cell lines in cis with c.1885A>G (p.R629G) or c.458T>A (p.D153V), appears to be a rare variant of uncertain clinical significance. The functional analysis of c.1885A>G and c.458T>A indicate that they are the disease-causing mutations in these two patients. The results presented here highlight the necessity of scanning the described intronic region for mutations in MUT-affected patients, followed by functional analyses to demonstrate the pathogenicity of the identified changes, and extend previous work of the applicability of the Antisense approach in methylmalonic aciduria (MMAuria) for a novel intronic mutation. Hum Mutat 30:1–7, 2009. © 2009 Wiley-Liss, Inc.
Klaus Wolff - One of the best experts on this subject based on the ideXlab platform.
-
Mcl-1 Antisense Therapy Chemosensitizes Human Melanoma in a SCID Mouse Xenotransplantation Model
The Journal of investigative dermatology, 2003Co-Authors: Christiane Thallinger, Markus Wolschek, Volker Wacheck, Helmut Maierhofer, Patrick Günsberg, Peter Polterauer, Hubert Pehamberger, Brett P. Monia, Edgar Selzer, Klaus WolffAbstract:It is well established that high expression of the antiapoptotic Bcl-2 family proteins Bcl-2 and Bcl-xL can significantly contribute to chemoresistance in a number of human malignancies. Much less is known about the role the more recently described Bcl-2 family member Mcl-1 might play in tumor biology and resistance to chemoTherapy. Using an Antisense strategy, we here address this issue in melanoma, a paradigm of a treatment-resistant malignancy. After in vitro proof of principle supporting an Antisense mechanism of action with specific reduction of Mcl-1 protein as a consequence of nuclear uptake of the Mcl-1 Antisense oligonucleotides employed, Antisense and universal control oligonucleotides were administered systemically in combination with dacarbazine in a human melanoma SCID mouse xenotransplantation model. Dacarbazine, available now for more than three decades, still remains the most active single agent for treatment of advanced melanoma. Mcl-1 Antisense oligonucleotides specifically reduced target protein expression as well as the apoptotic threshold of melanoma xenotransplants. Combined Mcl-1 Antisense oligonucleotide plus dacarbazine treatment resulted in enhanced tumor cell apoptosis and led to a significantly reduced mean tumor weight (mean 0.16 g, 95% confidence interval 0.08–0.26) compared to the tumor weight in universal control oligonucleotide plus dacarbazine treated animals (mean 0.35 g, 95% confidence interval 0.2–0.44) or saline plus dacarbazine treated animals (mean 0.39 g, 95% confidence interval 0.25–0.53). We thus show that Mcl-1 is an important factor contributing to the chemoresistance of human melanoma in vivo . Antisense Therapy against the Mcl-1 gene product, possibly in combination with Antisense strategies targeting other antiapoptotic Bcl-2 family members, appears to be a rational and promising approach to help overcome treatment resistance of malignant melanoma.
-
Chemosensitisation of malignant melanoma by BCL2 Antisense Therapy
Lancet (London England), 2000Co-Authors: B Jansen, Klaus Wolff, V. Wacheck, E. Heere-ress, H. Schlagbauer-wadl, Christoph Hoeller, T. Lucas, M. Hoermann, U. Hollenstein, H PehambergerAbstract:Summary Background Chemoresistance of malignant melanoma has been linked to expression of the proto-oncogene BCL2. Antisense oligonucleotides (ASO) targeted against BCL2 mRNA decreased BCL2 protein concentrations, increased tumour-cell apoptosis, and led to tumour responses in a mouse xenotransplantation model when combined with systemic dacarbazine. This phase I–II clinical study investigated the combination of BCL2 ASO (augmerosen, Genasense, G3139) and dacarbazine in patients with advanced malignant melanoma expressing BCL2. Methods In a within-patient dose-escalation protocol, 14 patients with advanced malignant melanoma were given augmerosen intravenously or subcutaneously in daily doses of 0·6-6·5 mg/kg plus standard dacarbazine treatment (total doses up to 1000 mg/m 2 per cycle). Toxicity was scored by common toxicity criteria. Plasma augmerosen concentrations were assayed by high-performance liquid chromatography. In serial tumour biopsy samples, BCL2 protein concentrations were measured by western blotting and tumour-cell apoptosis was assessed. Findings The combination regimen was well tolerated, with no dose-limiting toxicity. Haematological abnormalities were mild to moderate. Lymphopenia was common, but no febrile neutropenia occurred. Higher doses of augmerosen were associated with transient fever. Four patients had liver-function abnormalities that resolved within 1 week. Steady-state plasma concentrations of augmerosen were attained within 24 h, and increased with administered dose. By day 5, daily doses of 1·7 mg/kg and higher led to a median 40% decrease in BCL2 protein in melanoma samples compared with baseline, concomitantly with increased tumour-cell apoptosis, which was greatly increased after dacarbazine treatment. Six patients have shown antitumour responses (one complete, two partial, three minor). The estimated median survival of all patients now exceeds 12 months. Interpretation Systemic administration of augmerosen downregulated the target BCL2 protein in metastatic cancer. Such downregulation of BCL2, combined with standard anticancer Therapy, offers a new approach to the treatment of patients with resistant neoplasms.
-
bcl 2 Antisense Therapy chemosensitizes human melanoma in scid mice
Nature Medicine, 1998Co-Authors: Burkhard Jansen, Klaus Wolff, Hermine Schlagbauerwadl, Bob D Brown, Robert N Bryan, Andrea Van Elsas, Markus Muller, Hansgeorg Eichler, Hubert PehambergerAbstract:Malignant melanoma is a prime example of cancers that respond poorly to various treatment modalities including chemoTherapy1. A number of chemotherapeutic agents have been shown recently to act by inducing apoptosis, a type of cell death antagonized by the bcl-2 gene2. Human melanoma expresses Bcl-2 in up to 90% of all cases3–7. In the present study we demonstrate that bcl-2 Antisense oligonucleotide treatment improves the chemo-sensitivity of human melanoma grown in severe combined im-munodeficient (SCID) mice. Our findings suggest that reduction of Bcl-2 in melanoma, and possibly also in a variety of other tumors, may be a novel and rational approach to improve chemosensitivity and treatment outcome.