The Experts below are selected from a list of 291 Experts worldwide ranked by ideXlab platform

Wolfgang Walther - One of the best experts on this subject based on the ideXlab platform.

  • Jet-Injection of short hairpin RNA-encoding vectors into tumor cells.
    Methods in molecular biology (Clifton N.J.), 2010
    Co-Authors: Wolfgang Walther, Ulrike Stein, Hermann Lage
    Abstract:

    The use of the RNA interference (RNAi) through the expression of small hairpin RNA (shRNA) is a promising approach for efficient gene silencing for therapeutic applications. In this chapter, we describe the in vivo reversal of the classical MDR1/P-glycoprotein (MDR1/P-gp)-mediated multidrug resistance (MDR) phenotype by shRNA. For local intratumoral delivery of naked shRNA-encoding vector constructs, the nonviral Jet-Injection was used. This Jet-injector system uses compressed air to inject small volumes (5-10 muL) of naked nucleic acid solutions into tumor tissues. Furthermore, the design of the Jet-injector allows multiple Injections. Under our experimental design, the delivery of plasmid DNA encoding anti-MDR shRNA by Jet-Injection into human MDR1/P-gp overexpressing MaTu/ADR breast cancer xenografts resulted in a decrease of MDR1 mRNA expression level to more than 90%. Accordingly, the corresponding MDR1/P-gp protein is no longer detectable in the tumors after anti-MDR1 shRNA vector Injection. Furthermore, combination of two intratumoral Jet-Injections of anti-MDR1 shRNA vectors with two intravenous administrations of doxorubicin is sufficient for a complete reversal of the MDR phenotype in association with tumor growth inhibition.

  • Nonviral Jet-Injection technology for intratumoral in vivo gene transfer of naked DNA
    Methods in molecular biology (Clifton N.J.), 2009
    Co-Authors: Wolfgang Walther, Iduna Fichtner, Peter M. Schlag, Ulrike Stein
    Abstract:

    The main challenges for application of gene therapy to patients are poor selectivity in vector targeting, insufficient gene transfer, and great difficulties in systemic treatment in association with safety concerns for particular vector systems. For success in gene therapy, safe, applicable, and efficient transfer technologies are required. Because of the complex nature of targeted vector delivery to the tumor, our strategy for gene therapy is focused on the development of local nonviral gene transfer. This approach of local interference with tumor growth and progression could contribute to better control of the disease. Transfer of naked DNA is an important alternative to liposomal or viral systems. Different physical procedures are used for improved delivery of naked DNA into the target cells or tissues in vitro and in vivo. Among the various nonviral gene delivery technologies, Jet-Injection is gaining increased attractiveness, because this technique allows gene transfer into different tissues with deep penetration of naked DNA by circumventing the disadvantages associated with, e.g., viral vectors. The Jet-Injection technology is based on Jets of high velocity for penetration of the skin and underlaying tissues, associated with efficient transfection of the affected area. The Jet-Injection technology has been successfully applied for in vivo gene transfer in different tumor models. More importantly, the efficacy and safety of Jet-Injection gene transfer have recently been investigated in a phase I clinical trial.

  • Novel Jet-Injection Technology for Nonviral Intratumoral Gene Transfer in Patients with Melanoma and Breast Cancer
    Clinical cancer research : an official journal of the American Association for Cancer Research, 2008
    Co-Authors: Wolfgang Walther, M. Schleef, Robert J. Siegel, Dennis Kobelt, Thomas Knösel, Manfred Dietel, Andreas Bembenek, Jutta Aumann, Ruth Baier, Ulrike Stein
    Abstract:

    Purpose: This phase I clinical trial evaluated safety, feasibility, and efficiency of nonviral intratumoral Jet-Injection gene transfer in patients with skin metastases from melanoma and breast cancer. Experimental Design: Seventeen patients were enrolled. The patients received five Jet Injections with a total dose of 0.05 mg β-galactosidase (LacZ)-expressing plasmid DNA (pCMVβ) into a single cutaneous lesion. Clinical and laboratory safety monitoring were done. Systemic plasmid clearance was monitored by quantitative real-time PCR of blood samples throughout the study. All lesions were resected after 2 to 6 days. Intratumoral plasmid DNA load, DNA distribution, and LacZ expression was analyzed by quantitative real-time PCR, quantitative reverse transcription-PCR, Western blot, immunohistochemistry, and 5-bromo-4-chloro-3-indolyl-β-d-galactoside staining. Results: Jet Injection of plasmid DNA was safely done in all patients. No serious side effects were observed. Thirty minutes after Jet Injection, peak plasmid DNA levels were detected in the blood followed by rapid decline and clearance. Plasmid DNA and LacZ mRNA and protein expression were detected in all treated lesions. Quantitative analysis revealed a correlation of plasmid DNA load and LacZ-mRNA expression confirmed by Western blot. Immunohistochemistry and 5-bromo-4-chloro-3-indolyl-β-d-galactoside staining showed LacZ-protein throughout the tumor. Transfected tumor areas were found close and distant to the Jet-Injection site with varying levels of DNA load and transgene expression. Conclusion: Intratumoral Jet Injection of plasmid DNA led to efficient LacZ reporter gene expression in all patients. No side effects were experienced, supporting safety and applicability of this novel nonviral approach. A next step with a therapeutic gene product should determine antitumor efficacy of Jet-Injection gene transfer.

  • Uptake, Biodistribution, and Time Course of Naked Plasmid DNA Trafficking After Intratumoral In Vivo Jet Injection
    Human gene therapy, 2006
    Co-Authors: Wolfgang Walther, Iduna Fichtner, Peter M. Schlag, T. Minow, R. Martin, Ulrike Stein
    Abstract:

    Nonviral Jet Injection is an applicable technology for in vivo gene transfer of naked DNA. However, little is known about the biodistribution and clearance of Jet-injected DNA, or about its localization within tissue and cells. Therefore, in this study we analyzed the intratumoral and systemic biodistribution of Jet-injected naked DNA in human colon carcinoma-bearing NCr-nu/nu mice, which were Jet-injected with the pCMVbeta plasmid DNA. Intratumoral and systemic plasmid DNA biodistribution was analyzed 5, 10, 20, and 40 min and 3, 6, 24, 48, and 72 hr after Jet Injection, using quantitative real-time polymerase chain reaction. In the tumors, a rapid drop in naked DNA load within 24 hr of Jet Injection was shown. Detailed analysis of intratumoral distribution of rhodamine-labeled DNA revealed the presence of plasmid DNA within tumor cells 5 min after Jet Injection and further accumulation of significant DNA amounts in the cell nuclei 30 to 60 min after Jet Injection. In the blood, DNA amounts rapidly dropped within 10 to 40 min of Jet Injection to less than 0.001 pg of plasmid per 250 ng of tissue DNA and only minimal plasmid DNA dissemination was detected in liver, lung, spleen, kidney, and ovaries, which was cleared 3 to 6 hr after Jet Injection. By contrast, in heart, bone marrow, and brain almost no plasmid DNA was detectable.

  • Nonviral Jet-Injection gene transfer for efficient in vivo cytosine deaminase suicide gene therapy of colon carcinoma.
    Molecular therapy : the journal of the American Society of Gene Therapy, 2005
    Co-Authors: Wolfgang Walther, Ulrike Stein, Iduna Fichtner, Dennis Kobelt, Jutta Aumann, Franziska Arlt, Peter M. Schlag
    Abstract:

    Jet-Injection technology has developed into an efficient gene delivery system for nonviral in vivo gene transfer. In this study the Jet-injector system was used for the intratumoral gene transfer of small volumes of naked DNA encoding the Escherichia coli cytosine deaminase (CD) suicide gene. In our in vivo studies human colon carcinoma (patient-derived tumor model Colo5734 and SW480 colon carcinoma)-bearing NMRI-nu/nu male mice received four Jet Injections (10 microl per Injection) of the CD-gene-carrying plasmid, representing 40 microg plasmid DNA per animal. Forty-eight hours after Jet-Injection, treatment of tumors with 5-fluorocytosine (5-FC; 500 mg/kg ip) was started and during treatment tumor volumes were measured. Starting from day 5 of 5-FC treatment inhibition of tumor growth was seen in the CD-gene-transduced tumors compared to the respective control groups, which lasted for the entire observation time. Expression analysis at the mRNA and protein levels revealed efficient expression of the CD gene in the Jet-injected tumors. Therefore, in this in vivo study Jet-Injection gene transfer of 40 microg CD-expressing naked plasmid DNA leads to a significant tumor growth inhibition. This study demonstrates the applicability of the Jet-Injection technology for in vivo gene transfer into tumors to achieve efficient tumor gene therapy.

Ulrike Stein - One of the best experts on this subject based on the ideXlab platform.

  • Jet-Injection of short hairpin RNA-encoding vectors into tumor cells.
    Methods in molecular biology (Clifton N.J.), 2010
    Co-Authors: Wolfgang Walther, Ulrike Stein, Hermann Lage
    Abstract:

    The use of the RNA interference (RNAi) through the expression of small hairpin RNA (shRNA) is a promising approach for efficient gene silencing for therapeutic applications. In this chapter, we describe the in vivo reversal of the classical MDR1/P-glycoprotein (MDR1/P-gp)-mediated multidrug resistance (MDR) phenotype by shRNA. For local intratumoral delivery of naked shRNA-encoding vector constructs, the nonviral Jet-Injection was used. This Jet-injector system uses compressed air to inject small volumes (5-10 muL) of naked nucleic acid solutions into tumor tissues. Furthermore, the design of the Jet-injector allows multiple Injections. Under our experimental design, the delivery of plasmid DNA encoding anti-MDR shRNA by Jet-Injection into human MDR1/P-gp overexpressing MaTu/ADR breast cancer xenografts resulted in a decrease of MDR1 mRNA expression level to more than 90%. Accordingly, the corresponding MDR1/P-gp protein is no longer detectable in the tumors after anti-MDR1 shRNA vector Injection. Furthermore, combination of two intratumoral Jet-Injections of anti-MDR1 shRNA vectors with two intravenous administrations of doxorubicin is sufficient for a complete reversal of the MDR phenotype in association with tumor growth inhibition.

  • Nonviral Jet-Injection technology for intratumoral in vivo gene transfer of naked DNA
    Methods in molecular biology (Clifton N.J.), 2009
    Co-Authors: Wolfgang Walther, Iduna Fichtner, Peter M. Schlag, Ulrike Stein
    Abstract:

    The main challenges for application of gene therapy to patients are poor selectivity in vector targeting, insufficient gene transfer, and great difficulties in systemic treatment in association with safety concerns for particular vector systems. For success in gene therapy, safe, applicable, and efficient transfer technologies are required. Because of the complex nature of targeted vector delivery to the tumor, our strategy for gene therapy is focused on the development of local nonviral gene transfer. This approach of local interference with tumor growth and progression could contribute to better control of the disease. Transfer of naked DNA is an important alternative to liposomal or viral systems. Different physical procedures are used for improved delivery of naked DNA into the target cells or tissues in vitro and in vivo. Among the various nonviral gene delivery technologies, Jet-Injection is gaining increased attractiveness, because this technique allows gene transfer into different tissues with deep penetration of naked DNA by circumventing the disadvantages associated with, e.g., viral vectors. The Jet-Injection technology is based on Jets of high velocity for penetration of the skin and underlaying tissues, associated with efficient transfection of the affected area. The Jet-Injection technology has been successfully applied for in vivo gene transfer in different tumor models. More importantly, the efficacy and safety of Jet-Injection gene transfer have recently been investigated in a phase I clinical trial.

  • Novel Jet-Injection Technology for Nonviral Intratumoral Gene Transfer in Patients with Melanoma and Breast Cancer
    Clinical cancer research : an official journal of the American Association for Cancer Research, 2008
    Co-Authors: Wolfgang Walther, M. Schleef, Robert J. Siegel, Dennis Kobelt, Thomas Knösel, Manfred Dietel, Andreas Bembenek, Jutta Aumann, Ruth Baier, Ulrike Stein
    Abstract:

    Purpose: This phase I clinical trial evaluated safety, feasibility, and efficiency of nonviral intratumoral Jet-Injection gene transfer in patients with skin metastases from melanoma and breast cancer. Experimental Design: Seventeen patients were enrolled. The patients received five Jet Injections with a total dose of 0.05 mg β-galactosidase (LacZ)-expressing plasmid DNA (pCMVβ) into a single cutaneous lesion. Clinical and laboratory safety monitoring were done. Systemic plasmid clearance was monitored by quantitative real-time PCR of blood samples throughout the study. All lesions were resected after 2 to 6 days. Intratumoral plasmid DNA load, DNA distribution, and LacZ expression was analyzed by quantitative real-time PCR, quantitative reverse transcription-PCR, Western blot, immunohistochemistry, and 5-bromo-4-chloro-3-indolyl-β-d-galactoside staining. Results: Jet Injection of plasmid DNA was safely done in all patients. No serious side effects were observed. Thirty minutes after Jet Injection, peak plasmid DNA levels were detected in the blood followed by rapid decline and clearance. Plasmid DNA and LacZ mRNA and protein expression were detected in all treated lesions. Quantitative analysis revealed a correlation of plasmid DNA load and LacZ-mRNA expression confirmed by Western blot. Immunohistochemistry and 5-bromo-4-chloro-3-indolyl-β-d-galactoside staining showed LacZ-protein throughout the tumor. Transfected tumor areas were found close and distant to the Jet-Injection site with varying levels of DNA load and transgene expression. Conclusion: Intratumoral Jet Injection of plasmid DNA led to efficient LacZ reporter gene expression in all patients. No side effects were experienced, supporting safety and applicability of this novel nonviral approach. A next step with a therapeutic gene product should determine antitumor efficacy of Jet-Injection gene transfer.

  • Uptake, Biodistribution, and Time Course of Naked Plasmid DNA Trafficking After Intratumoral In Vivo Jet Injection
    Human gene therapy, 2006
    Co-Authors: Wolfgang Walther, Iduna Fichtner, Peter M. Schlag, T. Minow, R. Martin, Ulrike Stein
    Abstract:

    Nonviral Jet Injection is an applicable technology for in vivo gene transfer of naked DNA. However, little is known about the biodistribution and clearance of Jet-injected DNA, or about its localization within tissue and cells. Therefore, in this study we analyzed the intratumoral and systemic biodistribution of Jet-injected naked DNA in human colon carcinoma-bearing NCr-nu/nu mice, which were Jet-injected with the pCMVbeta plasmid DNA. Intratumoral and systemic plasmid DNA biodistribution was analyzed 5, 10, 20, and 40 min and 3, 6, 24, 48, and 72 hr after Jet Injection, using quantitative real-time polymerase chain reaction. In the tumors, a rapid drop in naked DNA load within 24 hr of Jet Injection was shown. Detailed analysis of intratumoral distribution of rhodamine-labeled DNA revealed the presence of plasmid DNA within tumor cells 5 min after Jet Injection and further accumulation of significant DNA amounts in the cell nuclei 30 to 60 min after Jet Injection. In the blood, DNA amounts rapidly dropped within 10 to 40 min of Jet Injection to less than 0.001 pg of plasmid per 250 ng of tissue DNA and only minimal plasmid DNA dissemination was detected in liver, lung, spleen, kidney, and ovaries, which was cleared 3 to 6 hr after Jet Injection. By contrast, in heart, bone marrow, and brain almost no plasmid DNA was detectable.

  • Nonviral Jet-Injection gene transfer for efficient in vivo cytosine deaminase suicide gene therapy of colon carcinoma.
    Molecular therapy : the journal of the American Society of Gene Therapy, 2005
    Co-Authors: Wolfgang Walther, Ulrike Stein, Iduna Fichtner, Dennis Kobelt, Jutta Aumann, Franziska Arlt, Peter M. Schlag
    Abstract:

    Jet-Injection technology has developed into an efficient gene delivery system for nonviral in vivo gene transfer. In this study the Jet-injector system was used for the intratumoral gene transfer of small volumes of naked DNA encoding the Escherichia coli cytosine deaminase (CD) suicide gene. In our in vivo studies human colon carcinoma (patient-derived tumor model Colo5734 and SW480 colon carcinoma)-bearing NMRI-nu/nu male mice received four Jet Injections (10 microl per Injection) of the CD-gene-carrying plasmid, representing 40 microg plasmid DNA per animal. Forty-eight hours after Jet-Injection, treatment of tumors with 5-fluorocytosine (5-FC; 500 mg/kg ip) was started and during treatment tumor volumes were measured. Starting from day 5 of 5-FC treatment inhibition of tumor growth was seen in the CD-gene-transduced tumors compared to the respective control groups, which lasted for the entire observation time. Expression analysis at the mRNA and protein levels revealed efficient expression of the CD gene in the Jet-injected tumors. Therefore, in this in vivo study Jet-Injection gene transfer of 40 microg CD-expressing naked plasmid DNA leads to a significant tumor growth inhibition. This study demonstrates the applicability of the Jet-Injection technology for in vivo gene transfer into tumors to achieve efficient tumor gene therapy.

Peter M. Schlag - One of the best experts on this subject based on the ideXlab platform.

  • Nonviral Jet-Injection technology for intratumoral in vivo gene transfer of naked DNA
    Methods in molecular biology (Clifton N.J.), 2009
    Co-Authors: Wolfgang Walther, Iduna Fichtner, Peter M. Schlag, Ulrike Stein
    Abstract:

    The main challenges for application of gene therapy to patients are poor selectivity in vector targeting, insufficient gene transfer, and great difficulties in systemic treatment in association with safety concerns for particular vector systems. For success in gene therapy, safe, applicable, and efficient transfer technologies are required. Because of the complex nature of targeted vector delivery to the tumor, our strategy for gene therapy is focused on the development of local nonviral gene transfer. This approach of local interference with tumor growth and progression could contribute to better control of the disease. Transfer of naked DNA is an important alternative to liposomal or viral systems. Different physical procedures are used for improved delivery of naked DNA into the target cells or tissues in vitro and in vivo. Among the various nonviral gene delivery technologies, Jet-Injection is gaining increased attractiveness, because this technique allows gene transfer into different tissues with deep penetration of naked DNA by circumventing the disadvantages associated with, e.g., viral vectors. The Jet-Injection technology is based on Jets of high velocity for penetration of the skin and underlaying tissues, associated with efficient transfection of the affected area. The Jet-Injection technology has been successfully applied for in vivo gene transfer in different tumor models. More importantly, the efficacy and safety of Jet-Injection gene transfer have recently been investigated in a phase I clinical trial.

  • Uptake, Biodistribution, and Time Course of Naked Plasmid DNA Trafficking After Intratumoral In Vivo Jet Injection
    Human gene therapy, 2006
    Co-Authors: Wolfgang Walther, Iduna Fichtner, Peter M. Schlag, T. Minow, R. Martin, Ulrike Stein
    Abstract:

    Nonviral Jet Injection is an applicable technology for in vivo gene transfer of naked DNA. However, little is known about the biodistribution and clearance of Jet-injected DNA, or about its localization within tissue and cells. Therefore, in this study we analyzed the intratumoral and systemic biodistribution of Jet-injected naked DNA in human colon carcinoma-bearing NCr-nu/nu mice, which were Jet-injected with the pCMVbeta plasmid DNA. Intratumoral and systemic plasmid DNA biodistribution was analyzed 5, 10, 20, and 40 min and 3, 6, 24, 48, and 72 hr after Jet Injection, using quantitative real-time polymerase chain reaction. In the tumors, a rapid drop in naked DNA load within 24 hr of Jet Injection was shown. Detailed analysis of intratumoral distribution of rhodamine-labeled DNA revealed the presence of plasmid DNA within tumor cells 5 min after Jet Injection and further accumulation of significant DNA amounts in the cell nuclei 30 to 60 min after Jet Injection. In the blood, DNA amounts rapidly dropped within 10 to 40 min of Jet Injection to less than 0.001 pg of plasmid per 250 ng of tissue DNA and only minimal plasmid DNA dissemination was detected in liver, lung, spleen, kidney, and ovaries, which was cleared 3 to 6 hr after Jet Injection. By contrast, in heart, bone marrow, and brain almost no plasmid DNA was detectable.

  • Nonviral Jet-Injection gene transfer for efficient in vivo cytosine deaminase suicide gene therapy of colon carcinoma.
    Molecular therapy : the journal of the American Society of Gene Therapy, 2005
    Co-Authors: Wolfgang Walther, Ulrike Stein, Iduna Fichtner, Dennis Kobelt, Jutta Aumann, Franziska Arlt, Peter M. Schlag
    Abstract:

    Jet-Injection technology has developed into an efficient gene delivery system for nonviral in vivo gene transfer. In this study the Jet-injector system was used for the intratumoral gene transfer of small volumes of naked DNA encoding the Escherichia coli cytosine deaminase (CD) suicide gene. In our in vivo studies human colon carcinoma (patient-derived tumor model Colo5734 and SW480 colon carcinoma)-bearing NMRI-nu/nu male mice received four Jet Injections (10 microl per Injection) of the CD-gene-carrying plasmid, representing 40 microg plasmid DNA per animal. Forty-eight hours after Jet-Injection, treatment of tumors with 5-fluorocytosine (5-FC; 500 mg/kg ip) was started and during treatment tumor volumes were measured. Starting from day 5 of 5-FC treatment inhibition of tumor growth was seen in the CD-gene-transduced tumors compared to the respective control groups, which lasted for the entire observation time. Expression analysis at the mRNA and protein levels revealed efficient expression of the CD gene in the Jet-injected tumors. Therefore, in this in vivo study Jet-Injection gene transfer of 40 microg CD-expressing naked plasmid DNA leads to a significant tumor growth inhibition. This study demonstrates the applicability of the Jet-Injection technology for in vivo gene transfer into tumors to achieve efficient tumor gene therapy.

  • Low-volume Jet Injection for efficient nonviral in vivo gene transfer
    Molecular Biotechnology, 2004
    Co-Authors: Wolfgang Walther, Ulrike Stein, Iduna Fichtner, Peter M. Schlag
    Abstract:

    The transfer of naked deoxyribonucleic acid (DNA) represents an alternative to viral and liposomal gene transfer technologies for gene therapy applications. Various procedures are employed to deliver naked DNA into the desired cells or tissues in vitro and in vivo, such as by simple needle Injection, particle bombardment, in vivo electroporation or Jet Injection. Among the various nonviral gene delivery technologies Jet Injection is gaining increasing acceptance because it allows gene transfer into different tissues with deeper penetration of the applied naked DNA. The versatile hand-held Swiss Jet injector uses pressurized air to force small volumes of 3 to 10 µL of naked DNA into targeted tissues. The β-galactosidase ( LacZ ) reporter gene construct and tumor necrosis factor α gene-expressing vectors were successfully Jet injected at a pressure of 3.0 bar into xenotransplanted human tumor models of colon carcinoma. Qualitative and quantitative expression analysis of Jet injected tumor tissues revealed the efficient expression of these genes in the tumors. Using this Swiss Jet-injector prototype repeated Jet Injections of low volumes (3–10 µL) into one target tissue can easily be performed. The key parameters of in vivo Jet Injection such as Jet Injection volume, pressure, Jet penetration into the tumor tissue, DNA stability have been defined for optimized nonviral gene therapy. These studies demonstrate the applicability of the Jet Injection technology for the efficient and simultaneous in vivo gene transfer of two different plasmid DNAs into tumors. It can be employed for nonviral gene therapy of cancer using minimal amounts of naked DNA.

  • Intratumoral low-volume Jet-Injection for efficient nonviral gene transfer
    Molecular Biotechnology, 2002
    Co-Authors: Wolfgang Walther, Carsten Voss, Thomas Nellessen, Ulrike Stein, Iduna Fichtner, M. Schleef, Torsten Schmidt, Peter M. Schlag
    Abstract:

    Jet-Injection has become an applicable technology among other established nonviral delivery systems, such as particle bombardment or in vivo electroporation. The low-volume Jet injector employed in this study uses compressed air to inject solutions of 1.5–10 µL containing naked DNA into the desired tissue. The novel design of this prototype makes multiple Jet-Injections possible. Therefore, repeated Jet-Injections into one target tissue can be performed easily. This Jet-injector hand-held system was used for the direct in vivo gene transfer of plasmid DNA into tumors to achieve efficient expression of reporter genes (β-galactosidase, green fluorescent protein [GFP]) and of therapeutic genes (TNF-α) in different tumor models. The study presented here revealed the key parameters of efficient in vivo Jet-Injection (Jet-Injection volume, pressure, Jet penetration, DNA stability) to define the optimal conditions for a Jet-Injection-aided nonviral gene therapy.

Iduna Fichtner - One of the best experts on this subject based on the ideXlab platform.

  • Nonviral Jet-Injection technology for intratumoral in vivo gene transfer of naked DNA
    Methods in molecular biology (Clifton N.J.), 2009
    Co-Authors: Wolfgang Walther, Iduna Fichtner, Peter M. Schlag, Ulrike Stein
    Abstract:

    The main challenges for application of gene therapy to patients are poor selectivity in vector targeting, insufficient gene transfer, and great difficulties in systemic treatment in association with safety concerns for particular vector systems. For success in gene therapy, safe, applicable, and efficient transfer technologies are required. Because of the complex nature of targeted vector delivery to the tumor, our strategy for gene therapy is focused on the development of local nonviral gene transfer. This approach of local interference with tumor growth and progression could contribute to better control of the disease. Transfer of naked DNA is an important alternative to liposomal or viral systems. Different physical procedures are used for improved delivery of naked DNA into the target cells or tissues in vitro and in vivo. Among the various nonviral gene delivery technologies, Jet-Injection is gaining increased attractiveness, because this technique allows gene transfer into different tissues with deep penetration of naked DNA by circumventing the disadvantages associated with, e.g., viral vectors. The Jet-Injection technology is based on Jets of high velocity for penetration of the skin and underlaying tissues, associated with efficient transfection of the affected area. The Jet-Injection technology has been successfully applied for in vivo gene transfer in different tumor models. More importantly, the efficacy and safety of Jet-Injection gene transfer have recently been investigated in a phase I clinical trial.

  • Uptake, Biodistribution, and Time Course of Naked Plasmid DNA Trafficking After Intratumoral In Vivo Jet Injection
    Human gene therapy, 2006
    Co-Authors: Wolfgang Walther, Iduna Fichtner, Peter M. Schlag, T. Minow, R. Martin, Ulrike Stein
    Abstract:

    Nonviral Jet Injection is an applicable technology for in vivo gene transfer of naked DNA. However, little is known about the biodistribution and clearance of Jet-injected DNA, or about its localization within tissue and cells. Therefore, in this study we analyzed the intratumoral and systemic biodistribution of Jet-injected naked DNA in human colon carcinoma-bearing NCr-nu/nu mice, which were Jet-injected with the pCMVbeta plasmid DNA. Intratumoral and systemic plasmid DNA biodistribution was analyzed 5, 10, 20, and 40 min and 3, 6, 24, 48, and 72 hr after Jet Injection, using quantitative real-time polymerase chain reaction. In the tumors, a rapid drop in naked DNA load within 24 hr of Jet Injection was shown. Detailed analysis of intratumoral distribution of rhodamine-labeled DNA revealed the presence of plasmid DNA within tumor cells 5 min after Jet Injection and further accumulation of significant DNA amounts in the cell nuclei 30 to 60 min after Jet Injection. In the blood, DNA amounts rapidly dropped within 10 to 40 min of Jet Injection to less than 0.001 pg of plasmid per 250 ng of tissue DNA and only minimal plasmid DNA dissemination was detected in liver, lung, spleen, kidney, and ovaries, which was cleared 3 to 6 hr after Jet Injection. By contrast, in heart, bone marrow, and brain almost no plasmid DNA was detectable.

  • Nonviral Jet-Injection gene transfer for efficient in vivo cytosine deaminase suicide gene therapy of colon carcinoma.
    Molecular therapy : the journal of the American Society of Gene Therapy, 2005
    Co-Authors: Wolfgang Walther, Ulrike Stein, Iduna Fichtner, Dennis Kobelt, Jutta Aumann, Franziska Arlt, Peter M. Schlag
    Abstract:

    Jet-Injection technology has developed into an efficient gene delivery system for nonviral in vivo gene transfer. In this study the Jet-injector system was used for the intratumoral gene transfer of small volumes of naked DNA encoding the Escherichia coli cytosine deaminase (CD) suicide gene. In our in vivo studies human colon carcinoma (patient-derived tumor model Colo5734 and SW480 colon carcinoma)-bearing NMRI-nu/nu male mice received four Jet Injections (10 microl per Injection) of the CD-gene-carrying plasmid, representing 40 microg plasmid DNA per animal. Forty-eight hours after Jet-Injection, treatment of tumors with 5-fluorocytosine (5-FC; 500 mg/kg ip) was started and during treatment tumor volumes were measured. Starting from day 5 of 5-FC treatment inhibition of tumor growth was seen in the CD-gene-transduced tumors compared to the respective control groups, which lasted for the entire observation time. Expression analysis at the mRNA and protein levels revealed efficient expression of the CD gene in the Jet-injected tumors. Therefore, in this in vivo study Jet-Injection gene transfer of 40 microg CD-expressing naked plasmid DNA leads to a significant tumor growth inhibition. This study demonstrates the applicability of the Jet-Injection technology for in vivo gene transfer into tumors to achieve efficient tumor gene therapy.

  • Low-volume Jet Injection for efficient nonviral in vivo gene transfer
    Molecular Biotechnology, 2004
    Co-Authors: Wolfgang Walther, Ulrike Stein, Iduna Fichtner, Peter M. Schlag
    Abstract:

    The transfer of naked deoxyribonucleic acid (DNA) represents an alternative to viral and liposomal gene transfer technologies for gene therapy applications. Various procedures are employed to deliver naked DNA into the desired cells or tissues in vitro and in vivo, such as by simple needle Injection, particle bombardment, in vivo electroporation or Jet Injection. Among the various nonviral gene delivery technologies Jet Injection is gaining increasing acceptance because it allows gene transfer into different tissues with deeper penetration of the applied naked DNA. The versatile hand-held Swiss Jet injector uses pressurized air to force small volumes of 3 to 10 µL of naked DNA into targeted tissues. The β-galactosidase ( LacZ ) reporter gene construct and tumor necrosis factor α gene-expressing vectors were successfully Jet injected at a pressure of 3.0 bar into xenotransplanted human tumor models of colon carcinoma. Qualitative and quantitative expression analysis of Jet injected tumor tissues revealed the efficient expression of these genes in the tumors. Using this Swiss Jet-injector prototype repeated Jet Injections of low volumes (3–10 µL) into one target tissue can easily be performed. The key parameters of in vivo Jet Injection such as Jet Injection volume, pressure, Jet penetration into the tumor tissue, DNA stability have been defined for optimized nonviral gene therapy. These studies demonstrate the applicability of the Jet Injection technology for the efficient and simultaneous in vivo gene transfer of two different plasmid DNAs into tumors. It can be employed for nonviral gene therapy of cancer using minimal amounts of naked DNA.

  • Intratumoral low-volume Jet-Injection for efficient nonviral gene transfer
    Molecular Biotechnology, 2002
    Co-Authors: Wolfgang Walther, Carsten Voss, Thomas Nellessen, Ulrike Stein, Iduna Fichtner, M. Schleef, Torsten Schmidt, Peter M. Schlag
    Abstract:

    Jet-Injection has become an applicable technology among other established nonviral delivery systems, such as particle bombardment or in vivo electroporation. The low-volume Jet injector employed in this study uses compressed air to inject solutions of 1.5–10 µL containing naked DNA into the desired tissue. The novel design of this prototype makes multiple Jet-Injections possible. Therefore, repeated Jet-Injections into one target tissue can be performed easily. This Jet-injector hand-held system was used for the direct in vivo gene transfer of plasmid DNA into tumors to achieve efficient expression of reporter genes (β-galactosidase, green fluorescent protein [GFP]) and of therapeutic genes (TNF-α) in different tumor models. The study presented here revealed the key parameters of efficient in vivo Jet-Injection (Jet-Injection volume, pressure, Jet penetration, DNA stability) to define the optimal conditions for a Jet-Injection-aided nonviral gene therapy.

Bryan P. Ruddy - One of the best experts on this subject based on the ideXlab platform.

  • subcutaneous nicotine delivery via needle free Jet Injection a porcine model
    Journal of Controlled Release, 2019
    Co-Authors: Bryan P. Ruddy, James W. Mckeage, Chris Bullen, Joanna Ting Wai Chu, Soo Hee Jeong, Bahareh Madadkhahsalmassi, Darren Svirskis, Malcolm D Tingle, Andrew J. Taberner
    Abstract:

    Subcutaneous delivery of nicotine was performed using a novel electrically-operated needle-free Jet injector, and compared to hypodermic needle delivery in a porcine model. Nicotine was delivered as a single, one-milligram dose into the abdominal skin, formulated as a 50 microliter aqueous solution. Plasma levels of nicotine and cotinine, its main metabolite, were then monitored over 2 h, following which the Injection site was excised for histological examination. No irritation or tissue damage were found at the Injection sites, and the Jet-injected nicotine exhibited comparable absorption into the systemic circulation to that injected using a conventional needle and syringe. The needle-free Jet Injection of nicotine is a promising and well tolerated method. The data presented from this porcine model will support a first in human trial towards a new promising nicotine replacement therapy.

  • a linear permanent magnet synchronous motor for large volume needle free Jet Injection
    IEEE Transactions on Industry Applications, 2019
    Co-Authors: Andrew J. Taberner, Bryan P. Ruddy
    Abstract:

    Needle-free Jet Injection allows delivery of liquid drugs through the skin in the form of a narrow fluid Jet traveling at high speed, minimizing the risk of accidents. The use of a controllable actuator to drive this process has many advantages, but the voice coil actuators previously used are too large and heavy for practical use with common Injection volumes (1 mL). We instead propose a compact slotless tubular linear permanent magnet synchronous motor design for Jet Injection. The design was determined by utilizing a semi-analytical electromagnetic modeling technique to predict the performance of any given motor design, an optimization scheme for the motor mass at a given power dissipation, and an automated routine for estimating cogging force using finite-element analysis. A prototype motor was constructed, with a nominal mass of 322 g, a stroke of 80 mm, and a target operating power of 1.2 kW; experimental data show that the motor constant is within 10% of the target, and that the cogging force is in close agreement with the model. Test ejection of water into a force sensor verified that the motor is fit for needle-free Injection. The design methodology explained here shows the benefits to integrated design optimization of both the actuator and the load, particularly in systems that drive fluid pressure loads, and also opens the door to controllable injector designs for larger volumes.

  • Application of Linear Permanent Magnet Flux-Switching Motors to Needle-free Jet Injection
    2019 IEEE Energy Conversion Congress and Exposition (ECCE), 2019
    Co-Authors: Nick N. L., Andrew J. Taberner, Bryan P. Ruddy
    Abstract:

    Needle-free Jet Injection allows delivery of a liquid drug through the skin in the form of a narrow fluid Jet traveling at high speed, minimizing the risks of accidents. Doing this in a controlled way requires an actuator with exceptionally high force density. We propose the use of linear permanent magnet flux-switching motors for this task, and describe their characteristics relative to the needs of Jet Injection. This paper will introduce a design process which involves the use of artificial neural networks as a means of response surface modelling, combined with nonlinear constraint optimization, to deduce a motor design that satisfies all of the challenging linear motor requirements for needle-free Jet Injection applications.

  • EMBC - Laterally Dispersing Nozzles for Needle-assisted Jet Injection
    Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Inte, 2019
    Co-Authors: James W. Mckeage, Bryan P. Ruddy, Poul M. F. Nielsen, Nandoun Abeysekera, Andrew J. Taberner
    Abstract:

    Most transdermal drug delivery systems are designed to inject drugs through the skin in a direction normal to the skin surface. However, in some applications, such as local anaesthesia, it is desirable to disperse the drug in a direction parallel to the surface of the skin. In this paper we present nozzles for needle-assisted Jet Injection that are designed to laterally disperse the fluid drug at a chosen depth in tissue. These nozzles were manufactured by laser machining holes in the walls of 0.57 mm (24 G) hypodermic needles, and sealing the ends of the needles. An existing controllable Jet Injection system was used to test the nozzles. High-speed video recordings were taken to examine the shape of the high-speed Jets emitted from the orifices, and Jet Injections into post mortem porcine tissue were performed to evaluate the resulting dispersion pattern. These Injections demonstrated the ability of these nozzles to achieve a widely spread dispersion at a depth of 3 mm to 4 mm in tissue. We observed that the widest dispersion occurred at the same depth as the orifices, and dispersion was greater in the direction of the Jets. Further investigation, including an in vivo study, is now required to evaluate whether this technique can reduce the time, cost or pain associated with transdermal local anaesthetic delivery.

  • Power-efficient controlled Jet Injection using a compound ampoule.
    Journal of Controlled Release, 2018
    Co-Authors: James W. Mckeage, Bryan P. Ruddy, Poul M. F. Nielsen, Andrew J. Taberner
    Abstract:

    Abstract We present a new mechanism for achieving needle free Jet Injection that significantly reduces the power required to perform a given Injection. Our ‘compound ampoule’ produces two phases of Jet speed under a constant force input by changing the effective piston area part-way through the Injection. In this paper we define the benefits associated with a compound ampoule, relative to those of the conventional single piston design, by developing expressions for the power and energy required to perform an Injection. We demonstrate that a compound ampoule can reduce the maximum input power required to perform a Jet Injection to less than one fifth of that previously required, enabling motors of less than half the mass to perform the same Injection. We then detail the development of a prototype compound ampoule injector. Results from testing of this prototype demonstrate the function of a compound ampoule and verify the expected reduction in the required power and energy. Injections into post mortem porcine tissue confirm that our compound ampoule prototype can achieve the delivery of 1 mL of liquid into post-mortem tissue at least as effectively as a conventional ampoule. This approach will advance progress toward light-weight and power-efficient needle-free Jet injectors for transdermal drug delivery.