ARTICLE ABSTRACT
CCDC134 is a poorly characterized secreted protein that may act as an immune cytokine. Here, we show that CCDC134 is differentially expressed on resting and activated immune cells and that it promotes CD8+ T-cell activation, proliferation, and cytotoxicity by augmenting expression of the T-cell effector molecules IFNγ, TNFα, granzyme B, and perforin. CCDC134 facilitated infiltration of CD8+ T cells with enhanced cytolytic activity into tumors, demonstrating strong antitumor effects in a CD8+ T-cell–dependent manner. Mechanistically, in CD8+ T cells, exposure to CCDC134 promoted cell proliferation through the JAK3–STAT5 pathway, a classic feature of many cytokines of the common γ-chain (γc) cytokine receptor family. Overall, our results provide evidence that CCDC134 may serve as a member of the γc cytokine family and illustrate its potent antitumor effects by augmenting CD8+ T-cell–mediated immunity. Cancer Res; 74(20); 5734–45. ©2014 AACR.
