Abstract
Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide, but effective therapies are still needed. The liver has been identified as an important immune organ and is heavily populated with various lymphocyte subsets known to play important roles in cancer immunosurveillance. We hypothesized that activation of hepatic lymphocytes by interleukin (IL)-15, a cytokine known for its ability to trigger proliferation and activation of natural killer (NK) cells, natural killer T cells, and memory CD8+ T cells, might offer an alternative therapy for HCC. We employed hepatotropic adeno-associated virus serotype 8 (AAV8) to deliver an IL-15 superagonist (IL-15-IL-15RαS), consisting of IL-15 covalently linked to the N-terminal sushi domain of the IL-15 receptor α chain, to achieve local sustained cytokine expression in the liver environment. We observed that a single injection of AAV8 expressing IL-15-IL-15RαS, but not IL-15 alone, greatly expanded the number of hepatic mononuclear cells, mainly NK cells, for at least 21 days. AAV8/IL-15-IL-15RαS treatment generated potent antitumor activity in a liver metastatic murine HCC model (BNL cells), and significantly prolonged the survival time of treated animals. The antitumor effect depended mainly on NK cells, not on CD8+ and CD4+ T cells, because AAV8/IL-15-IL-15RαS treatment greatly enhanced the cytolytic activity of hepatic NK cells and depletion of NK cells abrogated the therapeutic effect. Importantly, no apparent liver toxicity was observed during AAV8/IL-15-IL-15RαS treatment. Together, our data demonstrate that AAV8-delivered IL-15-IL-15RαS provides an effective and safe therapy against metastatic HCC.
Get full access to this article
View all access options for this article.
References
Supplementary Material
Please find the following supplemental material available below.
For Open Access articles published under a Creative Commons License, all supplemental material carries the same license as the article it is associated with.
For non-Open Access articles published, all supplemental material carries a non-exclusive license, and permission requests for re-use of supplemental material or any part of supplemental material shall be sent directly to the copyright owner as specified in the copyright notice associated with the article.
