Reactive myelopoiesis and FX-expressing macrophages triggered by chemotherapy promote cancer lung metastasis
Caijun Wu, … , Jun Yan, Chuanlin Ding
Caijun Wu, … , Jun Yan, Chuanlin Ding
Published March 28, 2023
Citation Information: JCI Insight. 2023;8(9):e167499. https://doi.org/10.1172/jci.insight.167499.
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Research Article Immunology

Reactive myelopoiesis and FX-expressing macrophages triggered by chemotherapy promote cancer lung metastasis

Abstract

Several preclinical studies have demonstrated that certain cytotoxic drugs enhance metastasis, but the importance of host responses triggered by chemotherapy in regulating cancer metastasis has not been fully explored. Here, we showed that multidose gemcitabine (GEM) treatment promoted breast cancer lung metastasis in a transgenic spontaneous breast cancer model. GEM treatment significantly increased accumulation of CCR2+ macrophages and monocytes in the lungs of tumor-bearing as well as tumor-free mice. These changes were largely caused by chemotherapy-induced reactive myelopoiesis biased toward monocyte development. Mechanistically, enhanced production of mitochondrial ROS was observed in GEM-treated BM Lin−Sca1+c-Kit+ cells and monocytes. Treatment with the mitochondria targeted antioxidant abrogated GEM-induced hyperdifferentiation of BM progenitors. In addition, GEM treatment induced upregulation of host cell–derived CCL2, and knockout of CCR2 signaling abrogated the pro-metastatic host response induced by chemotherapy. Furthermore, chemotherapy treatment resulted in the upregulation of coagulation factor X (FX) in lung interstitial macrophages. Targeting activated FX (FXa) using FXa inhibitor or F10 gene knockdown reduced the pro-metastatic effect of chemotherapy. Together, these studies suggest a potentially novel mechanism for chemotherapy-induced metastasis via the host response–induced accumulation of monocytes/macrophages and interplay between coagulation and inflammation in the lungs.

Authors

Caijun Wu, Qian Zhong, Rejeena Shrestha, Jingzhi Wang, Xiaoling Hu, Hong Li, Eric C. Rouchka, Jun Yan, Chuanlin Ding

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Figure 2

Chemotherapy-triggered host responses promote tumor metastasis in mice.

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Chemotherapy-triggered host responses promote tumor metastasis in mice. ...
Naive tumor-free C57BL/6 mice were treated with 4 doses of GEM (60 mg/kg, IP). Lung tissues and BM were harvested 2 days later after last treatment. (A) tSNE plot of major immune cell subsets in the lungs of PBS- and GEM-treated mice identified by FlowSOM clustering algorithm (gated on CD45+). (B) Summarized data of lung macrophages (CD11bhiF4/80+CD11c−) and CCR2+ macrophages from PBS- and GEM-treated mice (n = 5). (C) Summarized data of BM Ly6C+ monocytes gated on CD11b+ cell population (n = 4). (D) The PBS- and GEM-treated mice were IP injected with BrdU (2 mg per mouse). BM was collected 16 hours later, and the proliferating Ly6C+ cells stained for incorporated BrdU were analyzed by intracellular staining and flow cytometry (n = 3). (E) BM Ly6C+ cells from PBS- and GEM-treated mice were sorted and cocultured with CFSE-labeled OT-I splenocytes (1:1 ratio) in the presence of OVA (20 μg/mL) for 3 days. T cell proliferation was measured by flow cytometry (n = 4). (F) Tumor-free mice were treated with 4 doses of GEM and PBS, followed by intravenous injection of E0771-GFP cells (4 × 105 per mouse) 2 days later after last GEM treatment. Lung metastasis was determined at day 14 by measuring metastasis index (percentages of metastasis area to lung area). (G) Tumor burden in lungs of GEM-pretreated mice was determined by measuring GFP+ tumor cells within CD45− cell population (n = 7). (H) E0771-GFP cells (4 × 105 per mouse) were IV injected into GEM-pretreated mice 8 days later after last GEM treatment. Lung metastasis was determined by measuring GFP+ tumor cells within CD45− cell population (n = 5–6). (I) Regulatory T cells and IFN-γ–producing CD8+ T cells in GEM-pretreated tumor-bearing mice were evaluated by intracellular staining and flow cytometry (n = 7). (J and K) B6 tumor-free mice were treated by 4 doses of GEM and PBS. The CD4+/CD8+ depletion Abs (250 μg, IP, weekly) (J) or Ly6G depletion Ab (300 μg, IP, twice a week) (K) and IsoAb were used during the GEM or PBS pretreatment. Lung metastasis was determined by measuring GFP+ tumor cells within CD45− cell population after IV injection of E0771-GFP cells (n = 5–8). Data are representative of 2 independent experiments and presented as mean ± SEM. Each dot represents 1 mouse. *P < 0.05, **P < 0.01, ***P < 0.001, and ****P < 0.0001 by ordinary 1-way ANOVA (E, J, and K) or unpaired 2-sided t test (B–D and F–I).