Abstract 3785: ME-344, a novel isoflavone mitochondrial inhibitor, in combination with venetoclax constitutes a new metabolism-targeted approach to overcome resistance to Bcl-2 inhibition and standard of care treatment in AML
Authors: Hurrish Katie H. , Su Yongwei , Patel Shraddha , Wiley Sandra E. , Hou Zhanjun , Carter Jenna , Kalpage Hasini , Hüttemann Maik , Weng Connie , Edwards Holly , Polin Lisa , Li Jing , Yang Jay , Matherly Larry H. , Konoplev Sergej Naumovich , Taub Jeffrey W. , Konopleva Marina , Ge Yubin , Baran Natalia 
Published: June 2022

Abstract
Acute myeloid Leukemia (AML) is an aggressive hematologic malignancy with poor prognosis. Despite chromosomal and genetic heterogeneity, AML are uniformly characterized by increased reliance on oxidative phosphorylation (OXPHOS). This key metabolic hallmark of leukemia was recently reported as a feature of resistance to Cytarabine (AraC)-based therapy. Also, an aggressive phenotype and poor response to chemotherapy is associated with increased levels of Bcl-2. Despite the introduction of the Bcl-2 inhibitor venetoclax (VEN), the overall survival, particularly in older patients, remains poor. Thus, approaches to improve the sensitivity of leukemic cells to AraC-based or Bcl-2 based therapies are urgently needed.Here, we investigated the preclinical activity of ME-344, a novel isoflavone OXPHOS inhibitor, on AML cell lines and relapsed/refractory (R/R) patient samples in vitro and examined the efficacy of ME-344 in combination with VEN in Ara-C sensitive and resistant AML cell lines and patient-derived xenografts (PDX) both in vitro and in vivo.ME-344 (0-300 nM, 24 hr) significantly reduced viability of AML cell lines with EC50 of 75-100 nM and R/R AML patient samples with EC50 of 200-300 nM respectively. The cytotoxic response in AML was enhanced when ME-344 was combined with VEN, producing strong synergistic viability reduction and induction of apoptosis, as evidenced by Annexin V assay and an increased level of cleaved caspase 3 and PARP (immunoblotting). The dual inhibition of OXPHOS/Bcl-2 reduced Mcl-1 levels and showed efficacy in Mcl-1 overexpressingand Ara-C resistant AML models.Functional metabolic characterization of AML by transcriptomics and mass spectrometry demonstrated that ME-344 effectively inhibited biosynthetic pathways of nucleotides uncovering the purine biosynthesis pathway as crucial for therapeutic efficacy. ME-344 induced a dose-dependent decrease in the oxygen consumption rate (by Seahorse assay), in both AraC-sensitive and -resistant AML cell lines, and in R/R AML patient samples, which was further significantly potentiated by combination with VEN.Finally, in an aggressive AML xenograft model, ME-344 (200 mpk, i.v.) combined with subtherapeutic doses of VEN (25 mpk) reduced circulating leukemia burden and extended survival. Ongoing in vivo studies in AML PDX models will address the impact of ME-344 in the context of acquired AraC- and Bcl-2- resistance. In summary, our findings indicate ME-344 alone or in combination with Bcl-2 inhibition constitutes an important therapeutic modality that targets a unique metabolic vulnerability of AML.
Citation Format: Katie H. Hurrish, Yongwei Su, Shraddha Patel, Sandra E. Wiley, Zhanjun Hou, Jenna Carter, Hasini Kalpage, Maik Hüttemann, Connie Weng, Holly Edwards, Lisa Polin, Jing Li, Jay Yang, Larry H. Matherly, Sergej Naumovich Konoplev, Jeffrey W. Taub, Marina Konopleva, Yubin Ge, Natalia Baran. ME-344, a novel isoflavone mitochondrial inhibitor, in combination with venetoclax constitutes a new metabolism-targeted approach to overcome resistance to Bcl-2 inhibition and standard of care treatment in AML [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3785.