No abstract

Th17 cells have been described as short-lived but this view is at odds with their capacity to trigger protracted damage to normal and transformed tissues. We report that Th17 cells, despite displaying low expression of CD27 and other phenotypic markers of terminal differentiation, efficiently eradicated tumors and caused autoimmunity, were long-lived and maintained a core molecular signature resembling early memory CD8+ cells with stem cell-like properties. In addition, we found that Th17 cells had high expression of Tcf7, a direct target of the Wnt and β-catenin signaling axis, and accumulated β-catenin, a feature observed in stem cells. In vivo, Th17 cells gave rise to Th1-like effector cell progeny and also self-renewed and persisted as IL-17A-secreting cells. Multipotency was required for Th17 cell-mediated tumor eradication because effector cells deficient in IFN-γ or IL-17A had impaired activity. Thus, Th17 cells are not always short-lived and are a less-differentiated subset capable of superior persistence and functionality.

Purpose Infusion of interleukin-12 (IL-12) can mediate anti-tumor immunity in animal models, yet its systemic administration to patients with cancer results in minimal efficacy and severe toxicity. Here, we evaluated the anti-tumor activity of adoptively transferred human tumor infiltrating lymphocytes (TIL) genetically engineered to secrete single-chain IL-12 selectively at the tumor site. Experimental design Thirty-three patients with metastatic melanoma were treated in a cell-dose escalation trial of autologous TIL transduced with a gene encoding a single chain IL-12 driven by a nuclear factor of activated T cells promoter (NFAT.IL12). No IL-2 was administered. Results The administration of 0.001-0.1 X 109 NFAT.IL12 transduced TIL to 17 patients resulted in a single objective response (5.9%). However, at doses between 0.3-3 X 109 cells, 10 of 16 patients (63%) exhibited objective clinical responses. The responses tended to be short and the administered IL-12 producing cells rarely persisted at one month. Increasing cell doses were associated with high serum levels of IL-12 and gamma-interferon as well as clinical toxicities including liver dysfunction, high fevers and sporadic life threatening hemodynamic instability. Conclusions In this first-in-man trial, administration of TIL transduced with an inducible IL-12 gene mediated tumor responses in the absence of IL-2 administration using cell doses 10-100 fold lower than conventional TIL. However, due to toxicities, likely attributable to the secreted IL-12, further refinement will be necessary before this approach can be safely utilized in the treatment of cancer patients.

Adoptive cell therapy (ACT) using autologous tumor-infiltrating lymphocytes (TIL) can result in complete regression of advanced cancer in some patients, but the efficacy of this potentially curative therapy might be limited by poor persistence of TIL after adoptive-transfer. Pharmacologic inhibition of the serine/threonine kinase Akt has recently been shown to promote immunologic memory in viral-specific murine models, but whether this approach may enhance features of memory (e.g. long-term persistence) in TIL which are characteristically exhausted and senescent is not established. Here we show that pharmacologic inhibition of Akt enables expansion of TIL with the transcriptional, metabolic and functional properties characteristic of memory T cells. Consequently, Akt inhibition results in enhanced persistence of TIL after adoptive transfer into an immunodeficient animal model and augments anti-tumor immunity of CD8 T cells in a mouse model of cell-based immunotherapy. Pharmacologic inhibition of Akt represents a novel immunometabolomic approach to enhance the persistence of anti-tumor T cells and improve the efficacy of cell-based immunotherapy for metastatic cancer.