Cytokines are one of the first immunotherapeutics utilized in trials of human cancers with significant success. However, due to their significant toxicity and often lack of efficacy, cytokines have gi Show more
Cytokines are one of the first immunotherapeutics utilized in trials of human cancers with significant success. However, due to their significant toxicity and often lack of efficacy, cytokines have given their spotlight to other cancer immunotherapeutics such as immune checkpoint inhibitors. Nevertheless, only a subset of cancer patients respond to checkpoint inhibitors. Therefore, developing a novel cytokine-based immunotherapy is still necessary. Among an array of cytokine candidates, IL-27 is a unique one that exhibits clear anti-tumor activity with low toxicity. Systemically delivered IL-27 by adeno-associated virus (AAV-IL-27) is very well tolerized by mice and exhibits potent anti-tumor activity in a variety of tumor models. AAV-IL-27 exerts its anti-tumor activity through directly stimulation of immune effector cells and systemic depletion of Tregs, and is particularly suitable for delivery in combination with checkpoint inhibitors or vaccines. Additionally, AAV-IL-27 can also be delivered locally to tumors to exert its unique actions. In this review, we summarize the evidence that support these points and propose AAV-delivered IL-27 as a potential immunotherapeutic for cancer. Show less
IL-27 is an anti-inflammatory cytokine that has been shown to have potent anti-tumor activity. We recently reported that systemic delivery of IL-27 using recombinant adeno-associated virus (rAAV) indu Show more
IL-27 is an anti-inflammatory cytokine that has been shown to have potent anti-tumor activity. We recently reported that systemic delivery of IL-27 using recombinant adeno-associated virus (rAAV) induced depletion of Tregs and significantly enhanced the efficacy of cancer immunotherapy in a variety of mouse tumor models. A potential caveat of systemic delivery of IL-27 using rAAV is that there is no practical method to terminate IL-27 production when its biological activity is no longer needed. Therefore, in this work, we tested if directly injecting AAV-IL-27 into tumors could lead to similar anti-tumor effect yet avoiding uncontrolled IL-27 production. We found that high levels of IL-27 was produced in tumors and released to peripheral blood after AAV-IL-27 intra-tumoral injection. AAV-IL-27 local therapy showed potent anti-tumor activity in mice bearing plasmacytoma J558 tumors and modest anti-tumor activity in mice bearing B16.F10 tumors. Intra-tumoral injection of AAV-IL-27 induced infiltration of immune effectors including CD8 Show less