ABSTRACT
A critical factor in clinical development of cancer immunotherapies is the identification of tumor-associated antigens that may be related to immunotherapy potency. In this study, protein microarrays containing >8,000 human proteins were screened with serum from prostate cancer patients (N = 13) before and after treatment with a granulocyte-macrophage colony-stimulating factor (GM-CSF)-secreting whole cell immunotherapy. Thirty-three proteins were identified that displayed significantly elevated (P Subject(s)
Antibodies/blood
, Granulocyte-Macrophage Colony-Stimulating Factor/therapeutic use
, HSP90 Heat-Shock Proteins/biosynthesis
, Immunotherapy, Adoptive
, Nuclear Proteins/biosynthesis
, Prostatic Neoplasms/immunology
, Antibodies/immunology
, Biomarkers, Pharmacological
, Biomarkers, Tumor/immunology
, Clinical Trials as Topic
, Disease Progression
, Galectins/immunology
, HSP90 Heat-Shock Proteins/genetics
, HSP90 Heat-Shock Proteins/immunology
, High-Throughput Screening Assays
, Humans
, Male
, Neoplasm Metastasis
, Nuclear Proteins/genetics
, Nuclear Proteins/immunology
, Prognosis
, Prostatic Neoplasms/diagnosis
, Prostatic Neoplasms/mortality
, Prostatic Neoplasms/pathology
, Prostatic Neoplasms/therapy
, Protein Array Analysis
, Retrospective Studies
, Survival Analysis
, Treatment Outcome
ABSTRACT
Regulated gene expression may be required for the clinical development of certain gene therapies. Several approaches have been developed that allow pharmacologic control of transgene expression, including the dimerizer-regulated transcriptional system in which rapamycin or its analogs function as transcriptional inducers. These compounds can also act as direct antitumor agents via inhibition of mammalian target of rapamycin (mTOR). We describe the development of an optimized recombinant adeno-associated virus (AAV) expression cassette that allows dimerizer-regulated gene expression from a single vector in vitro and in vivo. After demonstrating multiple cycles of rapamycin-dependent transgene induction following a single administration of an AAV vector in vivo, application of this regulated AAV gene expression system to the pharmacologic control of antiangiogenic therapy was evaluated in preclinical tumor models. Dimerizer-regulated vectors were constructed encoding a soluble inhibitor of the vascular endothelial growth factor (VEGF) pathway. In two subcutaneous models of glioblastoma, regulated expression of the VEGF inhibitor via recombinant AAV-mediated gene transfer, in combination with rapamycin, was shown to decrease tumor growth rate significantly. The dual properties of rapamycin--as a transcriptional inducer and mTOR inhibitor--are exploited in combination with an AAV-encoded antiangiogenic agent to provide a novel approach for the treatment of malignant diseases.
Subject(s)
Dependovirus/genetics , Genetic Therapy/methods , Neoplasms/therapy , Sirolimus/pharmacology , Angiostatins/genetics , Angiostatins/metabolism , Animals , Blotting, Western , Cell Line , Cell Line, Tumor , Disease Models, Animal , Enzyme-Linked Immunosorbent Assay , Female , Gene Expression Regulation/drug effects , Gene Transfer Techniques , Genetic Vectors/genetics , Glioblastoma/genetics , Glioblastoma/metabolism , Glioblastoma/therapy , Humans , Immunosuppressive Agents/pharmacology , Mice , Mice, Nude , Neoplasms/blood supply , Neoplasms/genetics , Prealbumin/genetics , Promoter Regions, Genetic/genetics , Receptors, Vascular Endothelial Growth Factor/genetics , Receptors, Vascular Endothelial Growth Factor/metabolism , Vascular Endothelial Growth Factor A/antagonists & inhibitors , Xenograft Model Antitumor AssaysABSTRACT
In this study, recombinant AAV vectors pseudotyped with viral capsids derived from AAV serotypes 7 and 8 were evaluated for gene transfer in the murine striatum relative to vectors pseudotyped with AAV serotypes 2, 5, and 6. In comparison with rAAV serotype 2, pseudotyped vectors derived from AAV-7 and AAV-8 have increased transduction efficiency in the murine CNS, with the rank order rAAV-7 > rAAV-8 > rAAV-5 > rAAV-2 = rAAV-6, with all vectors demonstrating a marked tropism for neuronal transduction. Pseudotyped rAAV vector gene transfer in the brain after preimplantation of a murine 4C8 glioblastoma tumor was also evaluated. Efficiency of gene transfer to the orthotopic tumor was increased when using AAV-6, -7, and -8 capsid proteins in comparison with serotype 2, with the order rAAV-8 = rAAV-7 > rAAV-6 > rAAV-2 > rAAV-5. The increased gene transfer efficiency of rAAV vectors pseudotyped with the rAAV-8 capsid also provided enhanced therapeutic efficacy in a mouse model of glioblastoma multiforme, using vectors encoding an inhibitor of the vascular endothelial growth factor pathway. These studies demonstrate that rAAV vectors pseudotyped with capsids derived from AAV serotypes 7 and 8 provide enhanced gene transfer in the murine CNS and may offer increased therapeutic efficacy in the treatment of neurological disease.
