Lactate inhibits ATP6V0d2 expression in tumor-associated macrophages to promote HIF-2α–mediated tumor progression
Na Liu, … , Guoping Wang, Xiang-Ping Yang
Na Liu, … , Guoping Wang, Xiang-Ping Yang
Published November 15, 2018
Citation Information: J Clin Invest. 2019;129(2):631-646. https://doi.org/10.1172/JCI123027.
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Lactate inhibits ATP6V0d2 expression in tumor-associated macrophages to promote HIF-2α–mediated tumor progression

Abstract

Macrophages perform key functions in tissue homeostasis that are influenced by the local tissue environment. Within the tumor microenvironment, tumor-associated macrophages can be altered to acquire properties that enhance tumor growth. Here, we found that lactate, a metabolite found in high concentration within the anaerobic tumor environment, activated mTORC1 that subsequently suppressed TFEB-mediated expression of the macrophage-specific vacuolar ATPase subunit ATP6V0d2. Atp6v0d2–/– mice were more susceptible to tumor growth, with enhanced HIF-2α–mediated VEGF production in macrophages that display a more protumoral phenotype. We found that ATP6V0d2 targeted HIF-2α but not HIF-1α for lysosome-mediated degradation. Blockade of HIF-2α transcriptional activity reversed the susceptibility of Atp6v0d2–/– mice to tumor development. Furthermore, in a cohort of patients with lung adenocarcinoma, expression of ATP6V0d2 and HIF-2α was positively and negatively correlated with survival, respectively, suggesting a critical role of the macrophage lactate/ATP6V0d2/HIF-2α axis in maintaining tumor growth in human patients. Together, our results highlight the ability of tumor cells to modify the function of tumor-infiltrating macrophages to optimize the microenvironment for tumor growth.

Authors

Na Liu, Jing Luo, Dong Kuang, Sanpeng Xu, Yaqi Duan, Yu Xia, Zhengping Wei, Xiuxiu Xie, Bingjiao Yin, Fang Chen, Shunqun Luo, Huicheng Liu, Jing Wang, Kan Jiang, Feili Gong, Zhao-hui Tang, Xiang Cheng, Huabin Li, Zhuoya Li, Arian Laurence, Guoping Wang, Xiang-Ping Yang

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Figure 6

Deletion of Atp6v0d2 results in enhanced stabilization of HIF-2α.

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Deletion of Atp6v0d2 results in enhanced stabilization of HIF-2α. (A and...
(A and B) Whole-mount immunofluorescence staining of DAPI (blue), F4/80 (red), and HIF-2α (green) in tumor tissues of WT and Atp6v0d2–/– mice (A). Scale bars: 100 μm (original magnification, ×200). Higher-magnification insets are ×400. The percentage of HIF-2α+F4/80+ among F4/80+ cells was quantified manually (B). (C) Immunoblotting of HIF-2α, HIF-1α, P62, ATP6V0d2, and LC3 in WT and Atp6v0d2–/– BMDMs that were stimulated with LLC TCM for the indicated times. (D) WT BMDMs were transduced with control virus or retroviral ATP6V0d2 virus, followed by treatment with LLC TCM for the indicated times. The expression of HIF-2α, P62, ATP6V0d2, and LC3 was determined by immunoblotting. (E) Immunoblotting of HIF-2α, HIF-1α, and ATP6V0d2 in WT and Atp6v0d2–/– BMDMs that were stimulated with hypoxia (1% O2) for the indicated times. (F) Immunoblotting of HIF-2α, P62, and LC3 in WT and Atp6v0d2-/- BMDMs that were incubated with MG132 (20 μM) for the indicated times. (G) WT and Atp6v0d2–/– BMDMs were untreated, or treated with bafilomycin A (100 nM) for 6 hours. The expression of HIF-2α, P62, ATP6V0d2, and LC3 was determined by immunoblotting. (H and I) WT and Atp6v0d2–/– BMDMs were untreated or treated with MG132 (20 μM) for 4 hours. Cells were stained with anti–HIF-2α and LysoTracker (H). Original magnification, ×630 and ×2,520 (insets). Colocalization of HIF-2α and lysosomes among cytoplasmic HIF-2α was quantified (I). Data were assessed by Student’s t test and are representative of 2 (A and B) or 3 (C–I) independent experiments and are presented as mean ± SEM. *P < 0.05, ***P < 0.001.