UBC9 deficiency enhances immunostimulatory macrophage activation and subsequent antitumor T cell response in prostate cancer
Jun Xiao, … , Cong-Yi Wang, Zhi-Hua Wang
Jun Xiao, … , Cong-Yi Wang, Zhi-Hua Wang
Published January 10, 2023
Citation Information: J Clin Invest. 2023;133(4):e158352. https://doi.org/10.1172/JCI158352.
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Research Article Immunology Oncology

UBC9 deficiency enhances immunostimulatory macrophage activation and subsequent antitumor T cell response in prostate cancer

Abstract

The role of tumor-associated macrophages (TAMs), along with the regulatory mechanisms underlying distinct macrophage activation states, remains poorly understood in prostate cancer (PCa). Herein, we report that PCa growth in mice with macrophage-specific Ubc9 deficiency is substantially suppressed compared with that in wild-type littermates, an effect partially ascribed to the augmented CD8+ T cell response. Biochemical and molecular analyses revealed that signal transducer and activator of transcription 4 (STAT4) is a crucial UBC9-mediated SUMOylation target, with lysine residue 350 (K350) as the major modification site. Site-directed mutation of STAT4 (K350R) enhanced its nuclear translocation and stability, thereby facilitating the proinflammatory activation of macrophages. Importantly, administration of the UBC9 inhibitor 2-D08 promoted the antitumor effect of TAMs and increased the expression of PD-1 on CD8+ T cells, supporting a synergistic antitumor efficacy once it combined with the immune checkpoint blockade therapy. Together, our results demonstrate that ablation of UBC9 could reverse the immunosuppressive phenotype of TAMs by promoting STAT4-mediated macrophage activation and macrophage–CD8+ T cell crosstalk, which provides valuable insights to halt the pathogenic process of tumorigenesis.

Authors

Jun Xiao, Fei Sun, Ya-Nan Wang, Bo Liu, Peng Zhou, Fa-Xi Wang, Hai-Feng Zhou, Yue Ge, Tian-Tian Yue, Jia-Hui Luo, Chun-Liang Yang, Shan-Jie Rong, Ze-Zhong Xiong, Sheng Ma, Qi Zhang, Yang Xun, Chun-Guang Yang, Yang Luan, Shao-Gang Wang, Cong-Yi Wang, Zhi-Hua Wang

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Figure 2

Inhibition of UBC9 represses the progression of PCa.

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Inhibition of UBC9 represses the progression of PCa. (A) Schematic repre...
(A) Schematic representation of treatment of WT mice using the UBC9 inhibitor 2-D08. (B) Growth of subcutaneous RM-1 tumors in WT mice treated with DMSO or 2-D08 (n = 7 per group). (C and D) WT mice bearing RM-1 tumors received intratumoral injections of DMSO or 2-D08. After 11 days of treatment, the mice were sacrificed, and the tumors were weighed (n = 7 per group). (E) Representative dot plots and proportions of TAMs (F4/80+; CD11b+) on day 14 (n = 4 per group). (F) Representative dot plots and proportions of CD86+ TAMs from tumor-bearing mice treated with DMSO or 2-D08 (n = 4 per group). (G) MHC I expression level on TAMs from tumor-bearing mice treated with DMSO or 2-D08 (n = 4 per group). (H) Representative dot plots and proportions of tumor-infiltrating CD8+ T cells among CD45+ immune cells in DMSO- or 2-D08–treated mice (n = 4 per group). (I and J) Representative dot plots and proportions of IFN-γ+ (I) and PD-1+ (J) tumor-infiltrating CD8+ T cells (n = 4 per group). B was determined by log-rank test. Data in C and E–J represent mean ± SEM and were analyzed by Student’s t test (2 tailed). **P < 0.01; ***P < 0.001; ****P < 0.0001.