Project description:BackgroundInterleukin-12 (IL-12) is a cytokine well known for its role in immunity. A lesser known function of IL-12 is its role in hematopoiesis. The promising data obtained in the preclinical models of antitumor immunotherapy raised hope that IL-12 could be a powerful therapeutic agent against cancer. However, excessive clinical toxicity, largely due to repeat dose regimens, and modest clinical response observed in the clinical trials have pointed to the necessity to design protocols that minimize toxicity without affecting the anti-tumor effect of IL-12. We have focused on the lesser known role of IL-12 in hematopoiesis and hypothesized that an important clinical role for IL-12 in cancer may be as an adjuvant hematological cancer therapy. In this putative clinical function, IL-12 is utilized for the prevention of cancer therapy-related cytopenias, while providing concomitant anti-tumor responses over and above responses observed with the primary therapy alone. This putative clinical function of IL-12 focuses on the dual role of IL-12 in hematopoiesis and immunity.MethodsWe assessed the ability of IL-12 to facilitate hematopoietic recovery from radiation (625 rad) and chemotherapy (cyclophosphamide) in two tumor-bearing murine models, namely the EL4 lymphoma and the Lewis lung cancer models. Antitumor effects and changes in bone marrow cellularity were also assessed.ResultsWe show herein that carefully designed protocols, in mice, utilizing IL-12 as an adjuvant to radiation or chemotherapy yield facile and consistent, multilineage hematopoietic recovery from cancer therapy-induced cytopenias, as compared to vehicle and the clinically-utilized cytokine granulocyte colony-stimulating factor (G-CSF) (positive control), while still providing concomitant antitumor responses over and above the effects of the primary therapy alone. Moreover, our protocol design utilizes single, low doses of IL-12 that did not yield any apparent toxicity.ConclusionOur results portend that despite its past failure, IL-12 appears to have significant clinical potential as a hematological adjuvant cancer therapy.

Project description:ObjectiveIn this work, we examine the molecular basis for capillary tube regression and identify key proregressive factors, signaling pathways, and pharmacological antagonists of this process. Approach and Results: We demonstrate that the proinflammatory mediators, IL (interleukin)-1β, TNF (tumor necrosis factor) α, and thrombin, singly and in combination, are potent regulators of capillary tube regression in vitro. These proregressive factors, when added to endothelial cell-pericyte cocultures, led to selective loss of endothelial cell-lined tube networks, with retention and proliferation of pericytes despite the marked destruction of adjacent capillary tubes. Moreover, treatment of macrophages with the TLR (toll-like receptor) agonists Pam3CSK4 and lipopolysaccharide generates conditioned media with marked proregressive activity, that is completely blocked by a combination of neutralizing antibodies directed to IL-1β and TNFα but not to other factors. The same combination of blocking antibodies, as well as the anti-inflammatory cytokine IL-10, interfere with macrophage-dependent hyaloid vasculature regression in mice suggesting that proinflammatory cytokine signaling regulates capillary regression in vivo. In addition, we identified a capillary regression signaling signature in endothelial cells downstream of these proregressive agents that is characterized by increased levels of ICAM-1 (intercellular adhesion molecule-1), phospho-p38, and phospho-MLC2 (myosin light chain-2) and decreased levels of phospho-Pak2, acetylated tubulin, phospho-cofilin, and pro-caspase3. Finally, we identified combinations of pharmacological agents (ie, FIST and FISTSB) that markedly rescue the proregressive activities of IL-1β, TNFα, and thrombin, individually and in combination.ConclusionsOverall, these new studies demonstrate that the major proinflammatory mediators, IL-1β, TNFα, and thrombin, are key regulators of capillary tube regression-a critical pathological process regulating human disease.

Project description:By their selective infection or replication into tumors, oncolytic viruses trigger profound modifications of tumor immune microenvironment with a massive infiltration and activation of T cells. This tumor warming up can be further amplified by the local delivery of powerful immunomodulatory molecules encoded into virus’ genome. Those properties are particularly of interest for tumor poorly infiltrated or infiltrated with anergic T cells to reverse patient’s unresponsiveness to immune checkpoint inhibitors (ICI). TG6050 is a new oncolytic vaccinia virus encoding single-chain human Interleukin-12 (hIL-12) and full length anti-cytotoxic T-lymphocyte-associated antigen-4 (@CTLA-4) monoclonal antibody. Replication, oncolysis, selectivity, transgenes expression and functionality of TG6050 were characterized in vitro. Virus and IL-12 pharmacokinetics, antitumoral activities (alone or combined with ICI), and mechanism of action (MOA) were investigated in “hot” (highly infiltrated) and “cold” (poorly infiltrated) syngeneic murine tumor models. MOA was deciphered by monitoring both systemic and tumor immune responses, and tumor transcriptome analyses. Finally, TG6050 safety after repeated intravenous administrations was evaluated in cynomolgus monkeys and special attention was paid to the level of circulating IL-12 potentially associated with toxic effects. In vitro or in vivo replication of TG6050 in tumor cells allows local expression of functional IL-12 and @CTLA-4. The expression of transgenes, together with the virus replication, translated into an antitumoral activity in both “cold and “hot” tumor murine models that was further amplified by combination with ICI. Analysis of tumor microenvironment (TME) after TG6050 treatment showed an increase of interferon gamma, CD8+ T cells, M1/M2 macrophages ratio and a drastic decrease of regulatory T cells. Those local modifications were observed together with an enhanced systemic and specific antitumor adaptive immune response. In toxicology studies, the virus did not produce any observable adverse effects in cynomolgus monkeys. Conclusions: TG6050 allows the delivery of functional IL-12 and @CTLA-4 into tumor resulting in an excellent antitumor activity along with a shift towards an inflamed TME, and a boost of the systemic antitumor T-cells. Toxicological studies in macaques demonstrated the safety of TG6050. Together these results paved the way for clinical evaluation of TG6050 in metastatic non-small cell lung cancer (NCT05788926).

Dataset Information

Regression of prostate tumors after intravenous administration of lactoferrin-bearing polypropylenimine dendriplexes encoding TNF-?, TRAIL, and interleukin-12.

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Regression of prostate tumors after intravenous administration of lactoferrin-bearing polypropylenimine dendriplexes encoding TNF-α, TRAIL, and interleukin-12.

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