The potential therapeutic benefit of introducing IFN-gamma and GM-CSF genes in combination with the HSVtk suicide gene into subcutaneously implanted CT26 tumor cells was compared with that from each treatment alone. Cells, unmodified or retrovirally transduced with HSVtk or IFN-gamma/GM-CSF genes, were inoculated subcutaneously into syngeneic BALB/c mice in various combinations. HSVtk gene, with intraperitoneal ganciclovir treatment, reduced tumor volume by 81% at locally inoculated tumor sites (p<0.01) and by 25% at distantly inoculated tumor sites (p=0.052). IFN-gamma/GM-CSF genes showed a 56% tumor volume reduction at local tumor sites (p<0.01) and 15% volume reduction at remote tumor sites, although this was not statistically significant. The combination of HSVtk (with GCV) and IFN-gamma/GM-CSF genes showed an 81% volume reduction at local tumor sites (p<0.01) and a 43% volume reduction at remote tumor sites (p<0.01). Thus, the combination of HSVtk and IFN-gamma/GM-CSF gene therapy produced greater therapeutic efficacy than either treatment alone.
Animals ; Cell Line ; Cell Line, Tumor ; Gene Therapy/*methods ; Genes, Transgenic, Suicide ; Granulocyte Macrophage Colony-Stimulating Factors, Recombinant/biosynthesis/*genetics/therapeutic use ; H-2 Antigens/metabolism ; Interferon-gamma, Recombinant/biosynthesis/*genetics/therapeutic use ; Male ; Mice ; Mice, Inbred BALB C ; Neoplasms, Experimental/*therapy ; Research Support, Non-U.S. Gov't ; Simplexvirus/enzymology/genetics ; Thymidine Kinase/*genetics/therapeutic use ; Transduction, Genetic

Recent clinical evidence indicates that the non-eosinophilic subtype of severe asthma is characterized by fixed airway obstruction, which may be related to emphysema. Transgenic studies have demonstrated that high levels of IFN-gamma in the airways induce emphysema. Fibroblast growth factor 2 (FGF2), which is the downstream mediator of TGF-beta, is important in wound healing. We investigated the role of FGF2 in IFN-gamma-induced emphysema and the therapeutic effects of recombinant FGF2 in the prevention of emphysema in a severe non-eosinophilic asthma model. To evaluate the role of FGF2 in IFN-gamma-induced emphysema, lung targeted IFN-gamma transgenic mice were cross-bred with FGF2-deficient mice. A severe non-eosinophilic asthma model was generated by airway application of LPS-containing allergens twice a week for 4 weeks. To evaluate protective effects of FGF2, recombinant FGF2 (10 microg) was injected subcutaneously during allergen challenge in the severe asthma model. We found that non-eosinophilic inflammation and emphysema induced by transgenic overexpression of IFN-gamma in the airways were aggravated by the absence of FGF2. Airway challenge with LPS-containing allergens induced more inflammation in mice sensitized with LPS-containing allergens compared to challenge with allergens alone. In addition, LPS-induced lung inflammation and emphysema depended on IFN-gamma but not on IL-13. Interestingly, emphysema in the severe asthma model was significantly inhibited by treatment with recombinant FGF2 during allergen challenge, whereas lung inflammation was unaffected. Therefore, our present data suggest that FGF2 may help protect against IFN-gamma-induced emphysema, and that recombinant FGF2 may help lessen the severity of emphysema.
Animals ; Asthma/drug therapy/*prevention & control ; Bronchoalveolar Lavage Fluid ; Disease Models, Animal ; Emphysema/drug therapy/*prevention & control ; Enzyme-Linked Immunosorbent Assay ; Fibroblast Growth Factor 2/deficiency/*metabolism/*therapeutic use ; Flow Cytometry ; Inflammation/immunology ; Interferon-gamma/*biosynthesis/genetics ; Interleukin-13 ; Lipopolysaccharides/administration & dosage/pharmacology ; Mice ; Mice, Inbred C57BL ; Mice, Knockout ; Pulmonary Eosinophilia ; Recombinant Proteins/administration & dosage/therapeutic use