Adenovirus-mediated in vivo B7-1 gene transfer induces anti-tumor immunity against pre-established primary tumor and pulmonary metastasis of rat osteosarcoma

Novel Technologies for Isolated Lung Perfusion: Beyond Lung Transplant

Isolated lung perfusion (ILP) has been examined and developed in lung transplantation and thoracic oncology research. In lung transplantation, ILP has been used to assess physiologic integrity of donor lungs after removal from the donor, and it has also been proposed as a method for active treatment and repair of injured unsuitable donor organs ex vivo. ILP is attractive as a concept to deliver high-dose chemotherapy to treat pulmonary metastatic disease, referred to as in vivo lung perfusion. This article focuses on the rationale, technical aspects, and experimental and clinical experience of in vivo lung perfusion. A perspective on the future application of these techniques is described.

Gene therapy for osteosarcoma: steps towards clinical studies

Gene therapy, an applied form of biotechnology, relies on the delivery of foreign DNA into cells. More than 50% of all reported clinical trials for gene therapy are for cancer, though only a scant number for osteosarcoma. Osteosarcoma is a neoplasm afflicting young adults, who in their prime years of life suffer debilitation if not death. The disease is not entirely curable, even with surgery combined with aggressive chemotherapy. Thus, other forms of therapies are being evaluated, including gene therapy. There exist two major forms of gene transfer: viral and non-viral. This review only covers proof-of-principle work carried out in cancer beyond the cell culture stage, in animals. Drawing from the experiences of gene therapy against other cancers, studies for which have already reached the clinical phase, the review discusses potential pitfalls and solutions to enhance gene therapy for osteosarcoma.

Evolving gene therapy approaches for osteosarcoma using viral vectors: review

This review begins with an introduction to the malignant bone tumor, osteosarcoma [OS] and then moves to a discussion of the commonly used vectors for gene transfer. We first briefly highlight non-viral vectors including polymeric and liposomal delivery systems but concentrate predominantly on the 5 leading viral vectors used in cancer gene therapy, specifically retroviruses, adeno-associated viruses, herpes viruses and lentiviruses with the most detailed analysis reserved for adenoviruses. The 3 main strategies for gene therapy in osteosarcoma are next summarized. As part of this review, the several prodrug-converting enzymes utilized in OS suicide gene therapy are examined. The text then turns to a discussion of adenovirus-mediated gene transfer and the need for tumor targeting via transductional or transcriptional approaches. Because of practical problems with use of replication-incompetent viruses in achieving complete tumor kill in vivo, virotherapy utilizing replication competent viruses has come to the fore. This topic is, thus, next reviewed which allows for a natural transition to a discussion of armed therapeutic viruses many of which are conditionally replicating adenoviruses carrying transgenes with established anti-tumor efficacy. We recognize that several other issues have arisen which hamper progress in the field of cancer gene therapy. We, therefore, review viral-induced toxicity in the host and vector delivery issues which have been found to potentially influence safety. We end with a brief perspective including commenting on animal models used in examining delivery strategies for osteosarcoma gene therapy. The challenges remaining are touched upon most especially the need to deal with pulmonary metastatic disease from OS.

Adenovirus-mediated CD40 ligand therapy induces tumor cell apoptosis and systemic immunity in the TRAMP-C2 mouse prostate cancer model

BACKGROUND

The interaction between CD40 ligand (CD40L) and CD40 on antigen presenting cells is essential for the initiation of antigen-specific T-cell responses, whereas CD40L stimulation of CD40+ tumor cells can induce cellular apoptosis. We investigated the anti-tumor effects induced by CD40L gene transfer into the mouse prostate adenocarcinoma cell line TRAMP-C2, both in vitro and in vivo.

METHODS

TRAMP-C2 cells were transduced with an adenoviral vector encoding CD40L (AdCD40L). The induced expression of co-stimulatory molecules and cell viability was analyzed. AdCD40L-transduced TRAMP-C2 cells were used in prophylactic vaccination studies, while therapeutic studies were performed using peritumoral injections of AdCD40L.

RESULTS

AdCD40L yielded reduced TRAMP-C2 cell viability and induced apoptosis in vitro. Vaccination with CD40L-expressing TRAMP-C2 cells induced anti-tumor immunity and peritumoral AdCD40L injections induced tumor growth suppression.

CONCLUSIONS

Our observations highlight the therapeutic potential of using AdCD40L as a monotherapy or in combination with conventional chemotherapy or novel therapies (e.g., oncolytic viruses). The use of AdCD40L offers an attractive option for future clinical trials.

Local Delivery of Vaccinia Virus Expressing Multiple Costimulatory Molecules for the Treatment of Established Tumors

Successful immunotherapy of established tumors depends on overcoming the suppressive influence of the local tumor microenvironment. The direct injection of vaccinia virus expressing the B7.1 (CD80) costimulatory molecule into melanoma lesions resulted in local and systemic immunity with associated clinical responses. Therefore, we sought to evaluate the effects of a vaccinia virus expressing three costimulatory molecules, B7.1, ICAM-1, and LFA-3 (rV-TRICOM), in patients with metastatic melanoma. A standard dose escalation phase I clinical trial was performed. Thirteen patients were enrolled and 12 were available for follow-up. Local vaccination was feasible, with only low-grade injection site reactions associated with mild fatigue and myalgia reported. There was one occurrence of grade 1 vitiligo. Overall there was a 30.7% objective clinical response, with one patient achieving a complete response for more than 22 months. An inverse association was detected between anti-vaccinia antibody and anti-vaccinia T cell responses. Patients who failed to respond to vaccination but received high-dose interleukin-2 had a trend toward improved survival. Collectively, these results confirm the safety profile and feasibility of direct injection of vaccinia virus expressing multiple costimulatory molecules in patients with established tumors. Further clinical investigation is needed to better define the role of antigen, adjuvant cytokines, costimulation, and cross-presentation in the host immune response to local vaccination with vaccinia viruses expressing immunomodulatory molecules.

A quest for therapeutic antigens in bone and soft tissue sarcoma

Over the past three decades, there have been remarkable advances in the treatment of bone and soft tissue sarcomas. These include the introduction of adjuvant chemotherapy, establishment of guidelines for adequate surgical margins, and the development of post-excision reconstruction. There have also been advances in the field of immunotherapy against bone and soft tissue sarcomas, which, unfortunately, have received less attention. However, lack of progress in chemotherapy-based treatments for bone and soft tissue sarcomas has reignited interest in immunotherapeutic approaches. Here we summarize current progress in the immunotherapy of bone and soft tissue sarcomas including the strategies utilized to identify tumor-associated antigens, and the design of clinical trials.

IL-2/B7.1 (CD80) fusagene transduction of AML blasts by a self-inactivating lentiviral vector stimulates T cell responses in vitro: a strategy to generate whole cell vaccines for AML

Combined expression of costimulatory factors and proinflammatory cytokines stimulate effective immune-mediated tumor rejection in a variety of murine tumor models. Specifically, syngeneic tumor cells genetically modified to express B7.1 (CD80) have been shown to induce rejection of previously established murine solid tumors, and transduction with IL-2 can further increase survival. However, poor rates of gene transfer and inefficient expression of multiple transgenes encoded by single vectors have hampered the development of such autologous tumor cell vaccines for clinical trials in acute myeloid leukemia (AML) patients. Here we describe the development of a self-inactivating lentiviral vector encoding B7.1 and IL-2 as a single fusion protein postsynthetically cleaved to generate biologically active membrane-anchored B7.1 and secreted IL-2. This enables the efficient transduction of both established and primary AML blasts, resulting in expression of the transgenes in up to 98% of the cells following a single round of infection at an m.o.i. of 10. The combined expression of IL-2 and B7.1 in AML blasts enables increased stimulation of both allogeneic and autologous T cells. The stimulated lymphocytes secrete greater levels of Th1 cytokines and show evidence of specificity, as indicated by their increased proliferation in the presence of autologous AML compared to remission bone marrow cells.

Concurrent induction of T-cell activation and apoptosis of osteosarcoma cells by adenovirus-mediated B7-1/Fas chimeric gene transfer

To establish an effective B7-based gene therapy against osteosarcoma, we transferred B7-1/Fas chimeric gene adenovirally into poorly immunogenic osteosarcoma cells. We found that adenovirus-mediated rat B7-1/Fas gene transfer induced (i) expression of rat B7-1/Fas chimeric molecules in osteosarcoma cells, (ii) activation of murine T cells, (iii) apoptosis of murine osteosarcoma cells in the presence of anti-rat B7-1 mAb in vitro, and (iv) therapeutic effects more prominently than B7-1 gene transfer on the development of pulmonary metastasis and survival of mice. These findings collectively support the therapeutic value of adenovirus-mediated B7-1/Fas gene transfer on poorly immunogenic osteosarcoma, which is resistant to a treatment protocol using transduction of B7-1 alone.