The STAT3-MYC axis promotes survival of leukemia stem cells by regulating SLC1A5 and oxidative phosphorylation

• Published in: Blood Vol. 139; no. 4; pp. 584 - 596
• Main Authors: Amaya, Maria L., Inguva, Anagha, Pei, Shanshan, Jones, Courtney, Krug, Anna, Ye, Haobin, Minhajuddin, Mohammad, Winters, Amanda, Furtek, Steffanie L., Gamboni, Fabia, Stevens, Brett, D'Alessandro, Angelo, Pollyea, Daniel A., Reigan, Philip, Jordan, Craig T.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 27.01.2022; American Society of Hematology
• Subjects: Amino Acid Transport System ASC - metabolism; Cell Survival; Humans; Leukemia, Myeloid, Acute - metabolism; Minor Histocompatibility Antigens - metabolism; Myeloid Neoplasia; Neoplastic Stem Cells - cytology; Neoplastic Stem Cells - metabolism; Oxidative Phosphorylation; Proto-Oncogene Proteins c-myc - metabolism; Signal Transduction; STAT3 Transcription Factor - metabolism; Tumor Cells, Cultured
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood.2021013201

Acute myeloid leukemia (AML) is characterized by the presence of leukemia stem cells (LSCs), and failure to fully eradicate this population contributes to disease persistence/relapse. Prior studies have characterized metabolic vulnerabilities of LSCs, which demonstrate preferential reliance on oxidative phosphorylation (OXPHOS) for energy metabolism and survival. In the present study, using both genetic and pharmacologic strategies in primary human AML specimens, we show that signal transducer and activator of transcription 3 (STAT3) mediates OXPHOS in LSCs. STAT3 regulates AML-specific expression of MYC, which in turn controls transcription of the neutral amino acid transporter gene SLC1A5. We show that genetic inhibition of MYC or SLC1A5 acts to phenocopy the impairment of OXPHOS observed with STAT3 inhibition, thereby establishing this axis as a regulatory mechanism linking STAT3 to energy metabolism. Inhibition of SLC1A5 reduces intracellular levels of glutamine, glutathione, and multiple tricarboxylic acid (TCA) cycle metabolites, leading to reduced TCA cycle activity and inhibition of OXPHOS. Based on these findings, we used a novel small molecule STAT3 inhibitor, which binds STAT3 and disrupts STAT3-DNA, to evaluate the biological role of STAT3. We show that STAT3 inhibition selectively leads to cell death in AML stem and progenitor cells derived from newly diagnosed patients and patients who have experienced relapse while sparing normal hematopoietic cells. Together, these findings establish a STAT3-mediated mechanism that controls energy metabolism and survival in primitive AML cells. •STAT3 regulates amino acid influx and glutaminolysis in leukemia stem cells by promoting expression of MYC and SLC1A5.•Depletion of glutamine and its downstream metabolites leads to a decrease in OXPHOS activity in LSCs, resulting in cell death. [Display omitted]