A novel cancer therapeutic using thrombospondin 1 in dendritic cells.

Induction of thrombospondin 1 (TSP-1) is generally assumed to suppress tumor growth through inhibiting angiogenesis; however, it is less clear how TSP-1 in dendritic cells (DCs) influences tumor progression. We investigated tumor growth and immune mechanism by downregulation of TSP-1 in dendritic cells. Administration of TSP-1 small hairpin RNA (shRNA) through the skin produced anticancer therapeutic effects. Tumor-infiltrating CD4(+) and CD8(+) T cells were increased after the administration of TSP-1 shRNA. The expression of interleukin-12 and interferon-γ in the lymph nodes was enhanced by injection of TSP-1 shRNA. Lymphocytes from the mice injected with TSP-1 shRNA selectively killed the tumor cells, and the cytotoxicity of lymphocytes was abolished by depletion of CD8(+) T cells. Injection of CD11c(+) TSP-1-knockout (TSP-1-KO) bone marrow-derived DCs (BMDCs) delayed tumor growth in tumor-bearing mice. Similarly, antitumor activity induced by TSP-1-KO BMDCs was abrogated by depletion of CD8(+) T cells. In contrast, the administration of shRNAs targeting TSP-2, another TSP family member, did not extend the survival of tumor-bearing mice. Finally, TSP-1 shRNA functioned as an immunotherapeutic adjuvant to augment the therapeutic efficacy of Neu DNA vaccination. Collectively, the downregulation of TSP-1 in DCs produces an effective antitumor response that is opposite to the protumor effects by silencing of TSP-1 within tumor cells.

A novel cancer therapy by skin delivery of indoleamine 2,3-dioxygenase siRNA.

PURPOSE: Indoleamine 2,3-dioxygenase (IDO), an enzyme that degrades tryptophan, is a negative immune regulatory molecule of dendritic cells. IDO-expressing dendritic cells suppress T cell responses and may be immunosuppressive in vivo. We hypothesized that silencing the IDO expression in skin dendritic cells in vivo could elicit antitumor activity in tumor-draining lymph nodes. EXPERIMENTAL DESIGN: The efficiency of IDO-specific small interfering RNA (siRNA) was evaluated in vitro and in vivo. The therapeutic effect was evaluated in MBT-2 murine bladder tumor model and CT-26 colon tumor models. RESULTS: IDO expression was down-regulated in CD11c-positive lymphocytes after IDO siRNA treatment. In vivo skin administration of IDO siRNA inhibited tumor growth and prolonged survival in both tumor models. The number of infiltrated T cells and neutrophils increased at tumor sites, which are correlated with therapeutic efficacy. The T cells may be mainly responsible for the immunologic rejection because the effect was abolished by depletion of CD8-positive T cells. Adoptive transfer of CD11c-positive dendritic cells from vaccinated mice delayed tumor progression. The cancer therapeutic effect was reproducibly observed with another IDO siRNA targeting at different site, suggesting the effect was not due to off-target effect. In a neu-overexpressing MBT-2 tumor model, IDO siRNA enhanced the therapeutic efficacy of Her2/Neu DNA vaccine. Down-regulation of IDO2, an IDO homologue, with siRNA also generated antitumor immunity in vivo. CONCLUSIONS: Antitumor immunity can be effectively elicited by physical delivery of siRNAs targeting immunoregulatory genes in skin dendritic cells in vivo, as shown by IDO and IDO2 in this report.

Detection of Cigarette Smoke Using a Surface-Acoustic-Wave Gas Sensor with Non-Polymer-Based Oxidized Hollow Mesoporous Carbon Nanospheres.

The objective of this research was to develop a surface-acoustic-wave (SAW) sensor of cigarette smoke to prevent tobacco hazards and to detect cigarette smoke in real time through the adsorption of an ambient tobacco marker. The SAW sensor was coated with oxidized hollow mesoporous carbon nanospheres (O-HMC) as a sensing material of a new type, which replaced a polymer. O-HMC were fabricated using nitric acid to form carboxyl groups on carbon frameworks. The modified conditions of O-HMC were analyzed with Scanning Electron Microscopy (SEM), Fourier transform infrared spectrometry (FTIR), and X-ray diffraction (XRD). The appropriately modified O-HMC are more sensitive than polyacrylic acid and hollow mesoporous carbon nanospheres (PAA-HMC), which is proven by normalization. This increases the sensitivity of a standard tobacco marker (3-ethenylpyridine, 3-EP) from 37.8 to 51.2 Hz/ppm and prevents the drawbacks of a polymer-based sensing material. On filtering particles above 1 µm and using tar to prevent tar adhesion, the SAW sensor detects cigarette smoke with sufficient sensitivity and satisfactory repeatability. Tests, showing satisfactory selectivity to the cigarette smoke marker (3-EP) with interfering gases CH4, CO, and CO2, show that CO and CO2 have a negligible role during the detection of cigarette smoke.

Delivery of noncarrier naked DNA vaccine into the skin by supersonic flow induces a polarized T helper type 1 immune response to cancer.

BACKGROUND: DNA vaccine is a new and powerful approach to generate immunological responses against infectious disease and cancer. The T helper type (Th)1 immune response is usually required for generating effective anti-tumor responses. A microparticulate bombardment system can induce an immune response using very low amounts of DNA. Using nozzle aerodynamics, a low pressure gene gun has been developed to decrease the noise associated with high pressure gene guns. Particles are propelled by supersonic flow through this novel nozzle. To test whether this gun could inoculate a DNA vaccine that stimulates an anti-tumor Th1 immune response, we examined the effect of direct delivery of naked DNA (i.e. without any carrier) on the anti-tumor immune response of mice. METHODS: The luciferase reporter plasmid DNA was delivered using a low-pressure biolistic device and expressed in C3H/HeN, BALB/c, and C57BL/6 mice. RESULTS: Plasmid DNA expression was mainly in the epidermis. Noncarrier naked neu DNA vaccine and gold particle-coated neu DNA vaccine (at 1 microg per mouse) had similar anti-tumor effects in C3H mice. However, cytokine profile examination showed the Th1-bias of the response induced by naked DNA vaccine and the Th2-bias of the response induced by coated DNA vaccine. CONCLUSIONS: A shift in the immune response to favour enhanced tumor rejection can be achieved by skin delivery of naked DNA vaccine.