SIRT1 regulates metabolism and leukemogenic potential in CML stem cells
Ajay Abraham, … , Victor M. Darley-Usmar, Ravi Bhatia
Ajay Abraham, … , Victor M. Darley-Usmar, Ravi Bhatia
Published June 10, 2019
Citation Information: J Clin Invest. 2019;129(7):2685-2701. https://doi.org/10.1172/JCI127080.
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Research Article Hematology Oncology

SIRT1 regulates metabolism and leukemogenic potential in CML stem cells

Abstract

Chronic myeloid leukemia (CML) results from hematopoietic stem cell transformation by the BCR-ABL kinase. Despite the success of BCR-ABL tyrosine kinase inhibitors (TKIs) in treating CML patients, leukemia stem cells (LSCs) resist elimination and persist as a major barrier to cure. Previous studies suggest that overexpression of the sirtuin 1 (SIRT1) deacetylase may contribute to LSC maintenance in CML. Here, by genetically deleting SIRT1 in transgenic CML mice, we definitively demonstrated an important role for SIRT1 in leukemia development. We identified a previously unrecognized role for SIRT1 in mediating increased mitochondrial oxidative phosphorylation in CML LSCs. We showed that mitochondrial alterations were kinase independent and that TKI treatment enhanced inhibition of CML hematopoiesis in SIRT1-deleted mice. We further showed that the SIRT1 substrate PGC-1α contributed to increased oxidative phosphorylation and TKI resistance in CML LSCs. These results reveal an important role for SIRT1 and downstream signaling mechanisms in altered mitochondrial respiration in CML LSCs.

Authors

Ajay Abraham, Shaowei Qiu, Balu K. Chacko, Hui Li, Andrew Paterson, Jianbo He, Puneet Agarwal, Mansi Shah, Robert Welner, Victor M. Darley-Usmar, Ravi Bhatia

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Figure 7

SIRT1 deletion inhibits mitochondrial respiration in CML and normal hematopoiesis.

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SIRT1 deletion inhibits mitochondrial respiration in CML and normal hema...
Analysis of OCR and ECAR was performed using Seahorse XF analyzer to assess mitochondrial respiration and glycolysis. (A) OCR was measured in CML (n = 3) and normal (n = 5) c-Kit+ cells with sequential addition of oligomycin (Oligo, complex V inhibitor), FCCP (a protonophore), and antimycin A (AntiA, complex III inhibitor), to analyze ATP-linked respiration, proton leak respiration, maximal respiratory capacity, mitochondrial reserve capacity, and nonmitochondrial respiration. The upper panel shows the OCR profiles for CML and normal c-Kit+ cells. The lower panel shows mitochondrial bioenergetic parameters calculated from extracellular flux analysis. Mito, mitochondrial, Res, reserve. (B) ECAR was measured in CML (n = 3) and normal (n = 5) c-Kit+ cells with serial addition of oligomycin, FCCP, antimycin A, and 2-DG to measure basal glycolysis, glycolytic reserve, FCCP-sensitive glycolysis, maximal glycolysis, and nonglycolytic ECAR. The upper panel shows the ECAR profiles for CML and normal c-Kit+ cells. The lower panel shows the calculated glycolytic parameters. Glyco, glycolysis. (C and D) OCR and ECAR in CML Cre– (n = 8) and CML Cre+ SIRT1-deleted (SIRT1-KO; n = 7) c-Kit+ cells. (E and F) OCR and ECAR in normal Cre– (n = 8) and normal Cre+ SIRT1-deleted (n = 7) c-Kit+ cells. Error bars represent mean ± SEM. *P < 0.05; **P < 0.01; ***P < 0.001, 2-way ANOVA correcting for multiple comparisons by controlling the FDR using the 2-stage linear step-up procedure of Benjamini, Krieger, and Yekutieli. 3–6 assay replicate assays were performed for each sample.