PD-1 blockade inhibits osteoclast formation and murine bone cancer pain
Kaiyuan Wang, … , Matthew J. Hilton, Ru-Rong Ji
Kaiyuan Wang, … , Matthew J. Hilton, Ru-Rong Ji
Published June 2, 2020
Citation Information: J Clin Invest. 2020;130(7):3603-3620. https://doi.org/10.1172/JCI133334.
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PD-1 blockade inhibits osteoclast formation and murine bone cancer pain

Abstract

Emerging immune therapy, such as with the anti–programmed cell death–1 (anti–PD-1) monoclonal antibody nivolumab, has shown efficacy in tumor suppression. Patients with terminal cancer suffer from cancer pain as a result of bone metastasis and bone destruction, but how PD-1 blockade affects bone cancer pain remains unknown. Here, we report that mice lacking Pdcd1 (Pd1−/−) demonstrated remarkable protection against bone destruction induced by femoral inoculation of Lewis lung cancer cells. Compared with WT mice, Pd1−/− mice exhibited increased baseline pain sensitivity, but the development of bone cancer pain was compromised in Pd1−/− mice. Consistently, these beneficial effects in Pd1−/− mice were recapitulated by repeated i.v. applications of nivolumab in WT mice, even though nivolumab initially increased mechanical and thermal pain. Notably, PD-1 deficiency or nivolumab treatment inhibited osteoclastogenesis without altering tumor burden. PD-L1 and CCL2 are upregulated within the local tumor microenvironment, and PD-L1 promoted RANKL-induced osteoclastogenesis through JNK activation and CCL2 secretion. Bone cancer upregulated CCR2 in primary sensory neurons, and CCR2 antagonism effectively reduced bone cancer pain. Our findings suggest that, despite a transient increase in pain sensitivity following each treatment, anti–PD-1 immunotherapy could produce long-term benefits in preventing bone destruction and alleviating bone cancer pain by suppressing osteoclastogenesis.

Authors

Kaiyuan Wang, Yun Gu, Yihan Liao, Sangsu Bang, Christopher R. Donnelly, Ouyang Chen, Xueshu Tao, Anthony J. Mirando, Matthew J. Hilton, Ru-Rong Ji

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Figure 6

Bone cancer is associated with increased expression and secretion of PD-L1 in tumor-bearing mice.

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Bone cancer is associated with increased expression and secretion of PD-...
(A) sPD-L1 in culture medium of LLC or control (medium only without cells) revealed by ELISA. 1–1.5 × 106 cells were included per well. n = 4 cultures. (B) Increased serum sPD-L1 levels after tumor inoculation and the effects of human IgG and nivolumab. n = 6–7 male mice. (C) Flow cytometry analysis showing serum increase in PD-L1+ exosomes on day 8 after tumor inoculation. n = 4 male mice. NC, negative control. (D) Western blot revealing PD-L1 expression in ipsilateral (I) and contralateral (C) BM collected 8 days after tumor implantation. Top: representative Western blot bands. Bottom: quantification of PD-L1 expression levels. n = 6 male mice. (E) Western blot showing PD-L1 expression in tumor tissue of ipsilateral thigh (T) or paratumor tissue (P) 17 days after LLC inoculation. Top: Western blot bands. Bottom: quantification of PD-L1 expression. n = 4 male mice. (F) Immunostaining images showing PD-L1 expression in ipsilateral BM (Ipsi BM) and contralateral BM (Contra BM). Scale bar: 1000 μm. Low-magnification images on the left and right are enlarged in middle boxes. Scale bars: 50 μm. (G) Quantification of the percentage of PD-L1+ cells in BM. n = 3 male mice. Data are represented as mean ± SEM. *P < 0.05; **P < 0.01; ***P < 0.001, 2-tailed Student’s t test (A, C, D, E, and G) and repeated measures 2-way ANOVA with Bonferroni’s post hoc test (B).