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Published on: August 13, 2013
Development of an adenovirus vector with tetracycline-regulatable human tumor necrosis factor alpha gene expression
1Department of Molecular Oncology, University of Texas M.D. Anderson Cancer Center, The Woodlands 77381, USA.
Abstract:
Tumor necrosis factor alpha (TNF-alpha) is a multifunctional cytokine with direct antitumor activity. However, clinical trials using TNF-alpha for cancer treatment have been disappointing due in part to its severe side effects, and it has been estimated that TNF-alpha therapy would be effective only at 5-25 times the maximum tolerated dose. We have recently modified a tetracycline (Tc) repressor/operator-based mammalian gene expression system and have generated a Tc-responsive recombinant adenovirus vector, AdVtTA.TNF-alpha. A variety of human tumor cells and T lymphocytes transduced by AdVtTA.TNF-alpha secreted high-titer (5,000-100,000 pg/10(6) cells/24 h) and biologically active TNF-alpha in the absence of Tc. Expression of TNF-alpha in the transduced cells was nondetectable when the culture medium contained as little as 0.1 microg/ml of Tc. At least a fraction of the clonogenic cells from human peripheral blood stem cell concentrates were also transducible by AdVtTA.TNF-alpha. The availability of this type of adenovirus vector opens a door to tumor- or organ-specific delivery of high-dose TNF-alpha and other therapeutic gene products for systemic cancer gene therapy.
Insights
Researchers developed a novel gene therapy vector for cancer treatment. This tetracycline-regulated adenovirus delivers high doses of tumor necrosis factor alpha (TNF-alpha) specifically to tumor cells, overcoming previous limitations.
Area of Science:
- Oncology
- Gene Therapy
- Molecular Biology
Background:
- Tumor necrosis factor alpha (TNF-alpha) exhibits direct antitumor properties but has limited clinical use due to severe side effects and low efficacy at tolerated doses.
- Effective cancer treatment may require TNF-alpha doses 5-25 times higher than the maximum tolerated dose, posing significant challenges for systemic administration.
- Developing targeted delivery systems is crucial to harness TNF-alpha's therapeutic potential while mitigating toxicity.
Purpose of the Study:
- To engineer a controllable gene expression system for targeted delivery of high-dose TNF-alpha in cancer therapy.
- To create a tetracycline-responsive recombinant adenovirus vector (AdVtTA.TNF-alpha) for precise regulation of TNF-alpha production.
- To evaluate the efficacy and safety of this novel vector in transducing tumor cells and immune cells.
Main Methods:
- Modification of a tetracycline (Tc) repressor/operator-based mammalian gene expression system.
- Generation of a Tc-responsive recombinant adenovirus vector, AdVtTA.TNF-alpha.
- Transduction of various human tumor cells, T lymphocytes, and peripheral blood stem cells with AdVtTA.TNF-alpha.
- Quantification of secreted TNF-alpha levels and assessment of biological activity.
- Evaluation of Tc-mediated regulation of TNF-alpha expression.
Main Results:
- Transduced human tumor cells and T lymphocytes secreted high titers (5,000-100,000 pg/10(6) cells/24 h) of biologically active TNF-alpha in the absence of Tc.
- TNF-alpha expression was effectively suppressed to undetectable levels with as little as 0.1 microg/ml of Tc in the culture medium.
- A fraction of clonogenic cells from human peripheral blood stem cell concentrates were successfully transduced, indicating potential for stem cell-based therapy.
- The AdVtTA.TNF-alpha vector demonstrated controllable, high-level expression of TNF-alpha in target cells.
Conclusions:
- The developed AdVtTA.TNF-alpha adenovirus vector enables precise, controllable, and high-dose delivery of TNF-alpha.
- This system offers a promising strategy for tumor- or organ-specific gene therapy in cancer treatment.
- The ability to regulate therapeutic gene expression opens new avenues for systemic cancer gene therapy, potentially improving efficacy and reducing side effects.
