Tumor Microenvironment–Derived R-spondins Enhance Antitumor Immunity to Suppress Tumor Growth and Sensitize for Immune Checkpoint Blockade Therapy
Yuting Tang, Qian Xu, Liang Hu, Xiaomei Yan, Xiaomin Feng, Asumi Yokota, Weinan Wang, Di Zhan, Durga Krishnamurthy, David E. Ochayon, Lijun Wen, Li Huo, Huimin Zeng, Yingwan Luo, L. Frank Huang, Mark Wunderlich, Jiwang Zhang, Eric Vivier, Jianfeng Zhou, Stephen N. Waggoner, Gang Huang
Abstract
Natural killer (NK) cells and T cells are key effectors of antitumor immune responses and major targets of checkpoint inhibitors. In multiple cancer types, we find that the expression of Wnt signaling potentiator R-spondin genes (e.g., RSPO3) is associated with favorable prognosis and positively correlates with gene signatures of both NK cells and T cells. Although endothelial cells and cancer-associated fibroblasts comprise the R-spondin 3-producing cells, NK cells and T cells correspondingly express the R-spondin 3 receptor LGR6 within the tumor microenvironment (TME). Exogenous expression or intratumor injection of R-spondin 3 in tumors enhanced the infiltration and function of cytotoxic effector cells, which led to tumor regression. NK cells and CD8+ T cells independently and cooperatively contributed to R-spondin 3-induced control of distinct tumor types. The effect of R-spondin 3 was mediated in part through upregulation of MYC and ribosomal biogenesis. Importantly, R-spondin 3 expression enhanced tumor sensitivity to anti-PD-1 therapy, thereby highlighting new therapeutic avenues. SIGNIFICANCE: Our study identifies novel targets in enhancing antitumor immunity and sensitizing immune checkpoint inhibition, which provides a rationale for developing new immunotherapies against cancers. It also offers mechanistic insights on Wnt signaling-mediated modulation of anticancer immunity in the TME and implications for a putative R-spondin-LGR6 axis in regulating NK-cell biology. This article is highlighted in the In This Issue feature, p. 2945.