Targeting PIM2 improves antitumor immunity through promoting effector function and persistence of CD8 T cells
Yongxia Wu, Linlu Tian, Allison Pugel, Reza Alimohammadi, Qiao Cheng, Weiguo Cui, Michael I. Nishimura, Lauren E. Ball, Chien-Wei Lin, Shikhar Mehrotra, Andrew S. Kraft, Xue-Zhong Yu
Yongxia Wu, Linlu Tian, Allison Pugel, Reza Alimohammadi, Qiao Cheng, Weiguo Cui, Michael I. Nishimura, Lauren E. Ball, Chien-Wei Lin, Shikhar Mehrotra, Andrew S. Kraft, Xue-Zhong Yu
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Research Article Cell biology Immunology

Targeting PIM2 improves antitumor immunity through promoting effector function and persistence of CD8 T cells

Abstract

The PIM kinase family is critically involved in tumorigenesis, yet its role in primary T cells is understudied. We reported that PIM2, distinct from the other 2 isoforms, inhibits T cell responses to alloantigen. Here, we further established PIM2 as a key negative regulator in antitumor immunity. Pim2 deficiency in tumor antigen–specific or polyclonal T cells enhanced their ability to control tumor growth in murine breast cancer, melanoma, and leukemia models. Pim2 deficiency enhanced cytokine production and metabolic activities in tumor-infiltrating CD8 T cells. Pim2 deficiency increased TCF1 expression and memory-like phenotype in CD8 T cells from lymphoid organs. Mechanistically, PIM2 facilitated LC3 lipidation, P62 degradation, and autophagic flux in T cells, leading to impaired glycolysis and effector cytokine production. Furthermore, through modulating VPRBP kinase phosphorylation, PIM2 inhibited histone methyltransferase activity of EZH2 in CD8 T cells, causing disrupted memory-like phenotype. Notably, the PIM2 inhibitor JP11646 markedly enhanced antitumor T cell response. The immunosuppressive role of PIM2 was validated in human T cells, where inhibition of PIM2 enhanced antitumor responses in engineered human T cells, including melanoma-specific TCR T cells and CD19 CAR T cells. Collectively, PIM2 represents a promising target for improving cancer immunotherapy through enhancing effector differentiation and persistence of CD8 T cells.

Authors

Yongxia Wu, Linlu Tian, Allison Pugel, Reza Alimohammadi, Qiao Cheng, Weiguo Cui, Michael I. Nishimura, Lauren E. Ball, Chien-Wei Lin, Shikhar Mehrotra, Andrew S. Kraft, Xue-Zhong Yu

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Figure 8

Targeting PIM2 increases human T cell antitumor response.

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Targeting PIM2 increases human T cell antitumor response. (A) Pan T cell...
(A) Pan T cells were isolated from human PBMCs, transfected with sgRNA to silence PIM2, and stimulated with anti-CD3/CD28 for 3 days. PIM2 expression in T cells and percentages of IFN-γ+ and TNF-α+ in gated CD8 T cells are shown. (B and C) Pan T cells were isolated from human PBMCs, transfected with sgRNA to silence PIM2, and 48 hours later activated with anti-CD3 beads for 24 hours. Cells were then transduced with control or CD19 CAR vector and expanded in hrIL-7 and hrIL-15 for 7 days. NSG mice were i.v. injected with 0.5 × 106 luciferase-transduced Raji cells, and 6 days later 3 × 106 control T cells or CAR T product (including ~1 × 106 CAR+ cells) were infused. Survival and bioluminescence were monitored. (D) Human PBMCs were stimulated with 1 μg/mL anti-CD3 for 3 days. Percentages of IFN-γ+ cells in gated CD8 T cells are shown. (E and F) Activated human T cells were transduced with CD19 CAR vector with a truncated CD34 tag and then expanded in IL-2 for 5 days. CAR T cells were cultured with Raji cells at the ratios indicated with or without JP11646 overnight. Gating strategy (E) and percentage of killing of CD19+ target cells, CD34+ cells among CD8+ cells, and IFN-γ+ cells (F) among CD8+CD34+ cells. Data represent 2 independent experiments (A–F). (G) NSG mice were i.v. injected with 1 × 106 GFP+ Raji cells and 3 days later with 1 × 106 CAR+ T cells. JP11646 or vehicle was administrated i.p. at 7.5 mg/kg twice a week for 4 weeks. Survival was monitored. (H) Percentages of Raji (GFP+) cells in peripheral blood are shown on day 28. Data represent 2 independent experiments with n = 10 mice/group. Data were analyzed by 2-tailed Student’s t test (A), 1-way ANOVA (D and H), 2-way ANOVA (F), and log-rank test for survival curves (B and G). Data are shown as mean ± SEM from biological replicates. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001.