In-person Oral Presentation 34th Lorne Cancer Conference 2022

Serine biosynthesis is a metabolic vulnerability in FLT3-ITD-driven acute myeloid leukaemia (#43)

Stefan Bjelosevic 1 2 , Emily Gruber 1 2 , Andrea Newbold 1 , Carolyn Shembrey 3 4 , Jennifer Devlin 1 2 , Simon Hogg 1 2 , Lev Kats 1 2 , Izabela Todorovski 1 2 , Zheng Fan 1 2 , Thomas Abrehart 1 , Giovanna Pomilio 5 6 , Andrew Wei 5 6 7 , Gareth Gregory 1 8 , Stephin Vervoort 1 2 , Kristin Brown 1 9 , Ricky Johnstone 1 2
  1. Cancer Research Division, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia
  2. The Sir Peter MacCallum Department of Oncology, The University of Melbourne, Parville, VIC, Australia
  3. Centre for Cancer Research, The University of Melbourne, Melbourne, VIC, Australia
  4. Department of Clinical Pathology, The University of Melbourne, Melbourne, VIC, Australia
  5. Australian Centre for Blood Diseases, Monash University, Melbourne, VIC, Australia
  6. Department of Clinical Haematology, The Alfred Hospital, Melbourne, VIC, Australia
  7. Department of Pathology, The Alfred Hospital, Melbourne, VIC, Australia
  8. School of Clinical Sciences at Monash Health, Monash University, Clayton, VIC, Australia
  9. Department of Biochemistry and Pharmacology, The University of Melbourne, Melbourne, VIC, Australia

Mutations in the FMS-like tyrosine kinase 3 (FLT3) gene occur in approximately 30% of all acute myeloid leukaemias (AMLs) and are associated with poor prognosis. A majority of these mutations are in the form of in-frame internal tandem duplications (ITDs) in the juxtamembrane region of the FLT3 gene. Whilst small molecule inhibitors of FLT3 have entered clinical use, the utility of FLT3 inhibitor monotherapy has been limited by the rapid development of resistance, highlighting the need for identification of alternative therapeutic targets for the treatment of FLT3-mutant AML. Using human and murine models of FLT3-ITD-driven AML, we have recently demonstrated that FLT3-ITD promotes serine biosynthesis and uptake via ATF4-dependent transcriptional regulation of genes in the de novo serine biosynthesis pathway and neutral amino acid transport (Bjelosevic, et al. Cancer Discovery, 2021). Genetic or pharmacologic inhibition of phosphoglycerate dehydrogenase (PHGDH), the rate-limiting enzyme of de novo serine biosynthesis, selectively inhibited proliferation of FLT3-ITD AMLs in vitro and in vivo. Purine supplementation effectively rescued the antiproliferative effect of inhibiting FLT3-ITD, consistent with the hypothesis that serine fuels purine nucleotide synthesis in FLT3-ITD AML cells. Finally, we demonstrated that pharmacologic inhibition of PHGDH sensitized FLT3-ITD AMLs to the standard-of-care chemotherapeutic cytarabine via exacerbation of DNA damage. Collectively, these data reveal novel insights into FLT3-ITD-induced metabolic reprogramming and reveal a targetable vulnerability in this subset of disease.

 

*Kristin Brown & Ricky Johnstone are Co-Senior authors in this study.