IFN-γ and Fas/FasL are required for the antitumor and antiangiogenic effects of IL-12/pulse IL-2 therapy

Abstract

Systemic administration of IL-12 and intermittent doses of IL-2 induce complete regression of metastatic murine renal carcinoma. Here, we show that overt tumor regression induced by IL-12/pulse IL-2 is preceded by recruitment of CD8(+) T cells, vascular injury, disrupted tumor neovascularization, and apoptosis of both endothelial and tumor cells. The IL-12/IL-2 combination synergistically enhances cell surface FasL expression on CD8(+) T lymphocytes in vitro and induces Fas and FasL expression within tumors via an IFN-gamma-dependent mechanism in vivo. This therapy also inhibits tumor neovascularization and induces tumor regression by mechanisms that depend critically on endogenous IFN-gamma production and an intact Fas/FasL pathway. The ability of IL-12/pulse IL-2 to induce rapid destruction of tumor-associated endothelial cells and regression of established metastatic tumors is ablated in mice with a dysregulated Fas/FasL pathway. The common, critical role for endogenous IFN-gamma and the Fas/FasL pathway in early antiangiogenic effects and in antitumor responses suggests that early, cytokine-driven innate immune mechanisms and CD8(+) T cell-mediated responses are interdependent. Definition of critical early molecular events engaged by IL-12/IL-2 may provide new perspective into optimal therapeutic engagement of a productive host-antitumor immune response.

Multicolor Fluorescence-Based Approaches for Imaging Cytokine-Induced Alterations in the Neovascularization, Growth, Metastasis, and Apoptosis of Murine Neuroblastoma Tumors

“…In addition, implantation of POB UN0092 murine neuroblastoma cells (J.K. Stauffer et al, manuscript in preparation) 20 into syngeneic transgenic actin-GFP mice 21 results in the formation of tumors that are vascularized by green fluorescent hostderived vessels. Consistent with the mechanism of action by IL-12 in other preclinical models, [22][23][24] we have now validated the use of this model system by demonstrating that administration of IL-12 can potently inhibit the vascularization of POB UN0092 murine neuroblastoma tumors that have been established in actin-GFP mice. Counterstaining with DAPI provides tumor sections in which vessel density (green) as well as nuclear morphology (blue) in the vascular endothelial and tumor cell compartments can be directly evaluated and/or quantitated.…”

“…[22][23][24] We next validated that the model systems described previously could be used to investigate cytokine-induced alterations in the vascularization of neuroblastoma tumors. C57BL/6-TgN(ACTbEGFP)10sb mice bearing advanced 17-day established subcutaneous POB UN0092 neuroblastoma tumors were treated with IL-12 or vehicle alone as described in the Materials and Methods section.…”

A Tumor-selective Biotherapy With Prolonged Impact on Established Metastases Based on Cytokine Gene-engineered MSCs

“…The relevant molecular mechanisms mediating cross-repressive interactions between cytokine-engineered MSCs and tumor growth and metastases should be involved in multiple aspects including: first, MSCs tend to travel to the same homing destination as the migrating cancer stem cell 26 with unusual abilities to migrate to oncogenetic or metastatic sites and directly attack tumors by contacting target cells and inhibiting their Akt activity; 12,22,27 then, the AdIL-12, which is hidden in the MSCs can evade the immune system surveillance and be well tolerated by the host without inducing an unacceptable immune response; after this, AdIL-12 can be localized to tumor microenvironments to express the cytokine gradually without interfering with other systems and, consequently, improve the pharmacokinetics of IL-12 and minimize the inherent toxic effects radically; subsequently, the target-specific expression of IL-12 would induce rapid destruction of established tumor-associated endothelial cells and regression of metastatic tumor cells via the Fas/FasL pathway as well as by inhibiting Akt phosphorylation. [28][29][30] The target-aimed biomolecules could promote downregulation of the VEGF receptor-3 signaling pathway or blockade of ligands VEGF-D to prevent any unestablished lymphatic endothelium from sprouting, 31,32 in a similar manner as has been revealed by the immunohistochemistry assay. However, blocking of VEGF receptor-3 signaling could only suppress tumor lymphangiogenesis and metastases to regional LNs but not to the lungs.…”

Angiogenesis meets immunology: Cytokine gene therapy of cancer

“…Using a metastatic murine renal carcinoma model, Wiggington et al demonstrated that IL-12/IL-2 combination enhances FasL expression on the CD8+ T cell surface, and tumor rejection was preceded by recruitment of CD8+ FasL+ cells in the tumor microenvironment, suggesting a complex interaction of IFN-c and Fas/FasL pathways in mediating the therapeutic effects of IL-12 (Wigginton et al, 2001). NK cells may indeed contribute to IL-12 action by bringing about tumor cell death both directly and indirectly, through damaging of the vasculature.…”