To achieve in situ tumor antigen uptake and presentation, intratumoral administration of ex vivo-generated, genemodified murine bone marrow-derived dendritic cells (DC) was used in a murine lung cancer model. To attract mature host DC and activated T cells at the tumor site, the DC were transduced with an adenoviral vector expressing secondary lymphoid tissue chemokine (CCL21/SLC). Sixty percent of the mice treated with 10 6 DC-AdCCL21 intratumorally (7-10 ng/ml/10 6 cells/24 h of CCL21) at weekly intervals for 3 weeks showed complete tumor eradication, whereas only 25% of mice had complete resolution of tumors when mice were treated with fibroblasts expressing CCL21. In contrast only 12% of the mice treated with unmodified or control vector modified DC (DC-AdCV) showed complete tumor eradication. DC-AdCCL21 administration led to increases in the CD4 ؉ , CD8 ؉ , and CD3 ؉ CXCR3 ؉ T cells, as well as DC expressing CD11c ؉ DEC205 ؉ . CD4 ؉ CD25 ؉ T-regulatory cells infiltrating the tumors were markedly reduced after DC-AdCCL21 therapy. The tumor site cellular infiltrates were accompanied by the enhanced elaboration of granulocyte macrophage colony-stimulating factor, IFN-␥, MIG/CXCL9, IP-10/CXCL10, and interleukin 12, but decreases in the immunosuppressive mediators transforming growth factor  and prostaglandin E 2 . DC-AdCCL21-treated tumor-bearing mice showed enhanced frequency of tumor-specific T lymphocytes secreting IFN-␥, and tumor protective immunity was induced after DC-AdCCL21 therapy. In vivo depletion of IP-10/CXCL10, MIG/CXCL9, or IFN-␥ significantly reduced the antitumor efficacy of DCAdCCL21. These findings provide a strong rationale for the evaluation of DC-AdCCL21 in cancer immunotherapy.
The antitumor efficacy of EBV-induced molecule 1 ligand CC chemokine (ELC/CCL19) was evaluated in a murine lung cancer model. The ability of ELC/CCL19 to chemoattract both dendritic cells and T lymphocytes formed the rationale for this study. Compared with diluent-treated tumor-bearing mice, intratumoral injection of recombinant ELC/CCL19 led to significant systemic reduction in tumor volumes (p < 0.01). ELC/CCL19-treated mice exhibited an increased influx of CD4 and CD8 T cell subsets as well as dendritic cells at the tumor sites. These cell infiltrates were accompanied by increases in IFN-γ, MIG/CXCL9, IP-10/CXCL10, GM-CSF, and IL-12 but a concomitant decrease in the immunosuppressive molecules PGE2 and TGFβ. Transfer of T lymphocytes from ELC/CCL19 treated tumor-bearing mice conferred the antitumor therapeutic efficacy of ELC/CCL19 to naive mice. ELC/CCL19 treated tumor-bearing mice showed enhanced frequency of tumor specific T lymphocytes secreting IFN-γ. In vivo depletion of IFN-γ, MIG/CXCL9, or IP-10/CXCL10 significantly reduced the antitumor efficacy of ELC/CCL19. These findings provide a strong rationale for further evaluation of ELC/CCL19 in tumor immunity and its use in cancer immunotherapy.
Sigma receptors are unique endoplasmic reticulum proteins that mediate signaling for a variety of drugs. We determined the effect of sigma1 receptor agonists on immune responses in a syngeneic lung cancer model. Sigma1 receptor agonists, including cocaine, up-regulated splenocyte IL-10 mRNA and protein production in vitro in a sigma receptor-dependent, pertussis toxin-sensitive manner. In vivo, sigma1 receptor agonists promoted tumor growth and induced IL-10 at the tumor site. Increased tumor growth was prevented by administration of specific Abs to IL-10 or by administration of specific sigma1 receptor antagonists. We report that sigma1 receptor ligands, including cocaine, augment tumor growth through an IL-10 dependent mechanism.
The antitumor efficiency of dendritic cells transduced with an adenovirus vector expressing interleukin (IL)-7 (DC-AdIL-7) was evaluated in a murine model of spontaneous bronchoalveolar cell carcinoma. These transgenic mice (CC-10 TAg), expressing the SV40 large T antigen under the Clara cell promoter, develop bilateral multifocal pulmonary adenocarcinomas and die at 4 months as a result of progressive pulmonary tumor burden. Injection of DC-AdIL-7 in the axillary lymph node region (ALNR) weekly for 3 weeks led to a marked reduction in tumor burden with extensive lymphocytic infiltration of the tumors and enhanced survival. The antitumor responses were accompanied by the enhanced elaboration of interferon (IFN)-gamma and IL-12 as well as an increase in the antiangiogenic chemokines, IFN-gamma-inducible protein 10 (IP-10/CXCL10) and monokine induced by IFN-gamma (MIG/CXCL9). In contrast, production of the immunosuppressive mediators IL-10, transforming growth factor (TGF)-beta, prostaglandin E(2) (PGE(2)), and the proangiogenic modulator vascular endothelial growth factor (VEGF) decreased in response to DC-AdIL-7 treatment. Significant reduction in tumor burden in a model in which tumors develop in an organ-specific manner provides a strong rationale for further evaluation of DC-AdIL-7 in regulation of tumor immunity and its use in lung cancer genetic immunotherapy.
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