Administration route-dependent induction of antitumor immunity by interferon-alpha gene transfer.

Type I interferon (IFN) protein is a cytokine with pleiotropic biological functions that include induction of apoptosis, inhibition of angiogenesis, and immunomodulation. We have demonstrated that intratumoral injection of an IFN-α-expressing adenovirus effectively induces cell death of cancer cells and elicits a systemic tumor-specific immunity in several animal models. On the other hand, reports demonstrated that an elevation of IFN in the serum following an intramuscular delivery of a vector is able to activate antitumor immunity. In this study, we compared the intratumoral and systemic routes of IFN gene transfer with regard to the effect and safety of the treatment. Intratumoral injection of an IFN-α adenovirus effectively activated tumor-responsive lymphocytes and caused tumor suppression not only in the gene-transduced tumors but also in distant tumors, which was more effective than the intravenous administration of the same vector. The expression of co-stimulatory molecules on CD11c+ cells isolated from regional lymph nodes was enhanced by IFN gene transfer into the tumors. Systemic toxicity such as an elevation of hepatic enzymes was much lower in mice treated by intratumoral gene transfer than in those treated by systemic gene transfer. Our data suggest that the intratumoral route of the IFN vector is superior to intravenous administration, due to the effective induction of antitumor immunity and the lower toxicity. © 2010 Japanese Cancer Association

Development of peritoneal tumor-targeting vector by in vivo screening with a random peptide-displaying adenovirus library.

The targeting of gene transfer at the cell-entry level is one of the most attractive challenges in vector development. However, attempts to redirect adenovirus vectors to alternative receptors by engineering the capsid-coding region have shown limited success, because the proper targeting ligands on the cells of interest are generally unknown. To overcome this limitation, we have constructed a random peptide library displayed on the adenoviral fiber knob, and have successfully selected targeted vectors by screening the library on cancer cell lines in vitro. The infection of targeted vectors was considered to be mediated by specific receptors on target cells. However, the expression levels and kinds of cell surface receptors may be substantially different between in vitro culture and in vivo tumor tissue. Here, we screened the peptide display-adenovirus library in the peritoneal dissemination model of AsPC-1 pancreatic cancer cells. The vector displaying a selected peptide (PFWSGAV) showed higher infectivity in the AsPC-1 peritoneal tumors but not in organs and other peritoneal tumors as compared with a non-targeted vector. Furthermore, the infectivity of the PFWSGAV-displaying vector for AsPC-1 peritoneal tumors was significantly higher than that of a vector displaying a peptide selected by in vitro screening, indicating the usefulness of in vivo screening in exploring the targeting vectors. This vector-screening system can facilitate the development of targeted adenovirus vectors for a variety of applications in medicine

Peptide sequences selected from a peptide-display adenovirus library in peritoneal tumors of AsPC-1 cells.

<p>(): Numbers of repetition.</p>*<p>: Stop codon.</p

Infectivity of cancer cells with the adenovirus displaying the selected peptide.

<p>(a) Luciferase activities following infection of adenovirus vectors <i>in vitro</i>. The AsPC-1, PSN-1, SKOV3 and MKN45 cells were infected with adenovirus vectors (AdΔCAR-LucEGFP-PFW, AdΔCAR-LucEGFP-SYE, AdΔCAR-LucEGFP or Ad-LucEGFP), and 24 h later the luciferase activities were measured. (b) Competitive inhibition of transduction of the adenovirus vector with selected peptide. Transduction efficiencies of AdΔCAR-LucEGFP-PFW in AsPC-1 cells were evaluated at moi 30 in the presence of the cognate or a control unrelated peptide at 0.2–1.5 mmol/L. The data are expressed as the relative luciferase activity (luciferase activity in the presence of peptide/that in the absence of peptide). Control peptide: AQGQWAL.</p