Overexpression of the fructose transporter SLC2A5 (GLUT5) in association with PHGDH splicing dynamics is a venetoclax resistance mechanism in acute myeloid leukemia

Background: The combination of hypomethylating agents (HMA) with the Bcl-2 inhibitor venetoclax (VEN) has significantly advanced acute myeloid leukemia (AML) treatment. This therapy is approved for older patients and those with comorbidities. Objectives: We aimed to identify resistance mechanisms to HMA-VEN therapy using scRNA-Seq on primary AML samples. GLUT5 expression on AML progenitors from resistant and non-resistant patients was evaluated through immunoblotting and immunofluorescence. Seahorse and CRISPR experiments were conducted to validate the phenotype in the THP-1 AML monocyte cell line. Findings: scRNA-Seq revealed an upregulation of Leukemia Stem Cell (LSC) 17 scores in pre-treatment samples compared to HMA-VEN relapse samples. RNA velocity analysis indicated that LSCs in pre-treatment samples were the root cell population, while HMA-VEN relapse cells, specifically AML Blast 1, showed preferential splicing of PHGDH, a key serine synthesis pathway member, resulting in the overexpression of SLC2A5. GLUT5 was more frequently and intensely expressed on the cell surface in patients resistant to HMA-VEN. Seahorse assays demonstrated that fructose uptake via GLUT5 suppressed oxygen consumption in THP-1 cells following siRNA-mediated knockdown. Conclusions: Aberrant GLUT5 expression by leukemia progenitors represents a metabolic adaptation contributing to VEN resistance in AML. Overall design: Bone marrow specimens from two AML patients who initially achieved a complete remission to the combination of hypomethylating agents with the Bcl-2 inhibitor venetoclax (HMA-VEN), (CR, defined as less than 5% marrow blasts by morphology) then became refractory to HMA-VEN (HMA-VEN-Refractory) were analyzed by scRNA-Seq.