Baseline Il-17 Receptor Signaling Is Essential For Controlling Aberrant Jnk-Dependent Cellular Proliferation Via Maintenance Of Endogenous Level Of Ubiquitin-Editing Enzyme A20

Abstracts: AACR Special Conference on Translational Control of Cancer: A New Frontier in Cancer Biology and Therapy; October 27-30, 2016; San Francisco, CAThe molecular mechanisms underlying aberrant activation of NF-κB and JNK in cancer remain incompletely understood. Here, we demonstrate that baseline IL-17 receptor (IL-17R) signaling is essential for controlling aberrant NF-κB and JNK activation, and restraining JNK-dependent homeostatic cellular proliferation. Using a shRNA knockdown approach, we demonstrated in two murine tumor cell lines that IL-17RA silencing markedly enhanced tumor cell growth in vitro and in vivo . Through mapping IL-17R signaling pathways, we further demonstrated that baseline IL-17A/IL-17R signaling actively restrained JNK phosphorylation in vitro and in vivo via maintenance of basal expression of the ubiquitin-editing enzyme A20, a negative regulator of NF-κB and JNK. Remarkably, IL-17RA reconstitution evidently restored the A20 level, and suppressed cell proliferation and JNK activity in tumor cells. The reconstitution of A20 in IL-17RA knockdown subclones is able to restore the normal rate of cellular proliferation and associated JNK/c-Jun activity. Finally, meta-analysis of human cancer microarray and RNA sequencing datasets confirmed close co-expression of IL-17RA and A20. Furthermore, alterations (mutation, upregulation or downregulation) of IL-17RA level in melanoma and ER+ breast cancer patients showed poor survival rate compared to the respective patients with normal baseline IL-17RA expression. Together, our data demonstrates a previously unrecognized molecular mechanism underlying aberrant activation of NF-κB and JNK in cancer cells. This work has significantly advanced our understanding of the biological role of the proinflammatory IL-17R signaling and highlights its unique role in the maintenance of A20 to regulate the pathogenesis of human cancer at translational level.Citation Format: Chi Yan, Yang Lei, Anna L. Greenshields, David W. Hoskin, Tong-Jun Lin, Jun Wang. Baseline IL-17 receptor signaling is essential for controlling aberrant JNK-dependent cellular proliferation via maintenance of endogenous level of ubiquitin-editing enzyme A20. [abstract]. In: Proceedings of the AACR Special Conference on Translational Control of Cancer: A New Frontier in Cancer Biology and Therapy; 2016 Oct 27-30; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2017;77(6 Suppl):Abstract nr A20.