Bone marrow niche ATP levels determine leukemia-initiating cell activity via P2X7 in leukemic models
Xiaoxiao He, … , Ye Yu, Junke Zheng
Xiaoxiao He, … , Ye Yu, Junke Zheng
Published December 10, 2020
Citation Information: J Clin Invest. 2021;131(4):e140242. https://doi.org/10.1172/JCI140242.
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Research Article Hematology

Bone marrow niche ATP levels determine leukemia-initiating cell activity via P2X7 in leukemic models

Abstract

How particular bone marrow niche factors contribute to the leukemogenic activities of leukemia-initiating cells (LICs) remains largely unknown. Here, we showed that ATP levels were markedly increased in the bone marrow niches of mice with acute myeloid leukemia (AML), and LICs preferentially localized to the endosteal niche with relatively high ATP levels, as indicated by a sensitive ATP indicator. ATP could efficiently induce the influx of ions into LICs in an MLL-AF9–induced murine AML model via the ligand-gated ion channel P2X7. P2x7 deletion led to notably impaired homing and self-renewal capacities of LICs and contributed to an approximately 5-fold decrease in the number of functional LICs but had no effect on normal hematopoiesis. ATP/P2X7 signaling enhanced the calcium flux–mediated phosphorylation of CREB, which further transactivated phosphoglycerate dehydrogenase (Phgdh) expression to maintain serine metabolism and LIC fates. P2X7 knockdown resulted in a markedly extended survival of recipients transplanted with either human AML cell lines or primary leukemia cells. Blockade of ATP/P2X7 signaling could efficiently inhibit leukemogenesis. Here, we provide a perspective for understanding how ATP/P2X7 signaling sustains LIC activities, which may benefit the development of specific strategies for targeting LICs or other types of cancer stem cells.

Authors

Xiaoxiao He, Jiangbo Wan, Xiaona Yang, Xiuze Zhang, Dan Huang, Xie Li, Yejun Zou, Chiqi Chen, Zhuo Yu, Li Xie, Yaping Zhang, Ligen Liu, Shangang Li, Yuzheng Zhao, Hongfang Shao, Ye Yu, Junke Zheng

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Figure 4

P2X7 is required for the proliferation of human AML cells.

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P2X7 is required for the proliferation of human AML cells. (A) P2X7 mRNA...
(A) P2X7 mRNA levels were analyzed in AML cells and normal BM cells from TCGA database (AML, n = 173; normal n = 70). *P < 0.05 by Student’s t test. TPM, transcripts per million. (B) The relationship between P2X7 level and survival of AML patients from TCGA database (n = 75/group). **P < 0.01 by log-rank test. (C–E) The numbers of THP-1, U937, and MV4-11 cells were calculated after infection with shRNAs targeting P2X7 (sh-P2X7-1 and -2) or scrambled shRNA (n = 3). *P < 0.05, ***P < 0.001 by 2-way ANOVA with Sidak’s multiple-comparison test. (F) The overall survival was examined in the recipients transplanted with P2X7-knockdown (sh-P2X7-1 and -2) THP-1 cells and scrambled shRNA (n = 7). *P < 0.05 by log-rank test. (G) P2X7-mediated influx of ions into human CD34+ LICs was measured upon the sequential treatment with ATP and the P2X7 antagonist A-740003 (n = 3). (H–J) The numbers of human primary AML cells were counted upon P2X7 knockdown. Three patients’ samples were examined (AML 1–3) (n = 3). *P < 0.05, **P < 0.01, ***P < 0.001 by 2-way ANOVA with Sidak’s multiple-comparison test. (K) Representative images of colonies derived from human AML cells upon the knockdown of P2X7 by shRNAs (sh-P2X7-1 and -2) or those treated with scrambled shRNA control. (L and M) Colony numbers and derived total cell counts were examined in human AML cells upon the knockdown of P2X7 by shRNAs (sh-P2X7-1 and -2) and scrambled shRNA (n = 3). *P < 0.05, **P < 0.01, ***P < 0.001 by 2-way ANOVA with Sidak’s multiple-comparison test. (N–P) CD45+GFP+ human AML cells in the peripheral blood (N) (AML 1, n = 5) and the survival (O and P) (AML 1 and 2, n = 5) of the recipients transplanted with P2X7-knockdown (sh-P2X7-1 and -2) human AML cells or scrambled shRNA are shown. PB, peripheral blood. *P < 0.05, **P < 0.01 by 1-way ANOVA with Tukey’s multiple-comparison test (N) or log-rank test (O and P).