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 February 1, 2019; First published November 15, 2018
Citation Information: J Clin Invest. 2019;129(2):631-646. https://doi.org/10.1172/JCI123027.
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Categories: Research Article Immunology Oncology

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 1

Lactate activates mTORC1 signaling to suppress Atp6v0d2 expression in macrophages.

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Lactate activates mTORC1 signaling to suppress Atp6v0d2 expression in ma...
(A–C, E, and F) Atp6v0d2 mRNA expression was determined by qRT-PCR. (A and B) LLC tumor-conditioned medium (TCM) was collected after 5 days culture of LLC cells (100% confluence). BMDMs were stimulated with LLC TCM (A) or a concentration gradient of LLC TCM (B) for 6 hours. (C) BMDMs were stimulated with medium, LLC TCM, or boiled LLC TCM (b-TCM; 100°C, 5 minutes) for 6 hours. (D) Lactate concentration in LLC TCM was determined. (E) BMDMs were stimulated with a concentration gradient of lactate for 6 hours. (F) BMDMs were stimulated with LLC TCM alone, or with the addition of different doses of 2-cyano-3-(4-hydroxyphenyl)-2-propenoic acid (CHC), a monocarboxylate channel transporter inhibitor. (G and H) Representative histograms (G) and bar chart (H) show the mean fluorescence intensity (MFI) for pS6 expression on macrophages that were starved with Earle’s balanced salt solution (EBSS) for 2 hours, followed by replacement with fresh medium (control), or fresh medium with lactate, b-TCM, or TCM for 1 hour. (I) BMDMs were starved with EBSS for 2 hours, followed by replacement with fresh medium in the presence of lactate (40 mM) or complete TCM for the indicated times. The amounts of nuclear-cytoplasmic fractionation of TFEB and pS6 were determined by immunoblot and amounts of TFEB in the nuclei were quantified relative to lamin B1. (J) RAW264.7 cells were stimulated with lactate (40 mM) or TCM for 4 hours and the binding of TFEB in the Atp6v0d2 promoter was determined by chromatin immunoprecipitation. (K and L) BMDMs were stimulated with lactate (K) or TCM (L) for 6 hours in the presence or absence of 15-minute pretreatment with Torin (1 μM). Atp6v0d2 mRNA expression was determined by qRT-PCR. Data are representative of 3 independent experiments (A–I). Data were assessed by unpaired Student’s t test (A), 1-way ANOVA with Turkey’s test (B, C, E, F, and L) and are represented as mean ± SEM. *P < 0.05, **P < 0.01, ***P < 0.001. LA, lactate.