Induction of antitumor immunity by direct intratumoral injection of a recombinant adenovirus vector expressing interleukin-12

Abstract

Direct intratumoral (i.t.) injection of adenoviruses (Ads) expressing specific immunostimulatory cytokines represents an attractive strategy for the clinical implementation of cytokine gene therapy of cancer. Interleukin-12 (IL-12) is a heterodimeric cytokine produced by antigen-presenting cells and promotes a T helper 1-like immune response. We have constructed an Ad vector (AdCMV-mIL-12) containing both chains of the murine IL-12 (mIL-12) gene linked by an internal ribosomal entry site sequence under the transcriptional control of the cytomegalovirus immediate-early gene promoter, which is able to mediate the transient expression of very high levels of biologically active mIL-12 both in vitro and in vivo. An i.t. injection of 4 ϫ 10 8 plaque-forming units of AdCMV-mIL-12 resulted in a complete regression of day 7 established subcutaneous MC38 murine adenocarcinomas and MCA205 murine fibrosarcomas. Treated animals rejected a subsequent rechallenge with MC38 and MCA205, respectively, demonstrating the induction of long-lasting antitumor immunity. Specific antitumor cytotoxic T lymphocyte reactivity was detected in splenocytes harvested from treated animals. A significant increase in the numbers of both CD4 ϩ and CD8 ϩ T cells in the AdCMV-mIL-12-infected tumors was observed. Ad-mediated IL-12 gene therapy was also associated with measurable serum levels of mIL-12 and profound changes in the composition of splenic lymphocytes. Taken together, these results demonstrate the feasibility and efficacy of delivering IL-12 directly i.t. using a recombinant adenoviral vector.

Local and systemic antitumor effect of intratumoral and peritumoral IL-12 electrogene therapy on murine sarcoma

“…Even though viral gene therapy is believed to be superior to nonviral in terms of transfection efficiency, 39 intratumoral IL-12 EGT produced higher complete response rates compared to adenoviral intratumoral delivery of the same therapeutic gene in sarcomas, where up to 70-80% complete response rates were reached. 4,5,7 Furthermore, in our experiment, this antitumor and none of the studies compared the effectiveness of the intra-and peritumoral approach in any type of tumor model. The main advantage of EGT, compared to viral vectors, is its nonexistent toxicity, low cost and simplicity of large scale vector (plasmid DNA) preparation.…”

“…For example, single intratumoral IL-12 viral delivery into Meth-A fibrosarcoma did not produce any systemically detected cytokine expression. 5 On the other hand, very high serum concentrations of both cytokines were achieved with gene therapy of MCA205 fibrosarcoma, 4 with the IL-12 concentration reaching up to 8 ng/ml of serum on day 2 and rapidly dropping to only 0.1 ng/ml by day 6 after intratumoral application of the adenoviral construct. The serum concentration of IFNγ peaked 2 days after therapy at 4.1 ng/ml and declined to 2.0 ng/ml by day 6.…”

“…Viral delivery was instituted using adenoviral vectors, which were delivered primarily intratumorally, for example into different types of fibrosarcoma [4][5][6] and Ewing's sarcoma. 7 Adenoviral constructs expressing IL-12 were also delivered intranasally for treatment of osteosarcoma lung metastases.…”

Cytokine-armed vaccinia virus infects the mesothelioma tumor microenvironment to overcome immune tolerance and mediate tumor resolution

“…approach remains a viable proposition. [14][15][16][17][18][19][20][21][22][23] Despite the apparent safety of the mesothelioma VV clinical trial, 12 safety issues continue to be a concern. Another member of the Poxviridae family, Fowlpox virus (FPV), undergoes abortive replication in the cytoplasm of mammalian cells allowing for transcription of inserted genes without production of functional FPV particles, thereby reducing safety concerns.…”

Cytokine-secreting herpes viral mutants effectively treat tumor in a murine metastatic colorectal liver model by oncolytic and T-cell-dependent mechanisms

“…[17][18][19][20][21][22][23][24][25][26] Like GM-CSF, IL-12 has been shown to induce antitumor immunity when delivered to tumor by adenoviral vectors or other strategies. [27][28][29][30][31][32][33][34] We have begun to investigate the potential to combine oncolytic viral therapy with cytokine gene therapy by treating a murine model of micrometastatic liver disease with oncolytic HSV-1 mutants genetically engineered to express the murine GM-CSF and IL-12 cytokine genes. Replication-competent oncolytic viral mutants have previously been combined with replication-defective vectors expressing cytokine genes in flank tumor models.…”