Abstract / Summary
Background: Metabolic plasticity contributes to therapeutic resistance in T-cell lymphoma, but the metabolic dependencies underlying tyrosine kinase inhibitor (TKI) resistance remain poorly understood. ATP citrate lyase (ACLY), which converts citrate to cytosolic acetyl-CoA, links glucose metabolism to lipogenesis and acetylation-dependent regulation. We hypothesized that ACLY represents an actionable metabolic vulnerability in lymphoma.
Methods: Structure-guided drug discovery and biochemical screening were used to identify the novel ACLY inhibitor VCB1. VCB1 was evaluated against recombinant human ACLY and in TKI-sensitive and TKI-resistant lymphoma models. Antitumor activity was assessed by proliferation, cell-cycle analysis, apoptosis, and immunoblotting, followed by integrated transcriptomic, metabolomic, and lipidomic profiling.
Results: Our xenograft study showed that ACLY dependence in ALK+ALCL. We discovered novel ACLY inhibitor VCB1 directly inhibited recombinant ACLY with uM potency (IC₅₀, 0.9 uM) and strongly suppressed lymphoma cell growth. In ALK inhibitor-sensitive SUPM2, VCB1 showed an IC₅₀ of 0.299 uM and retained potency in lorlatinib-resistant SUPM2-LR1000 cells (1.62 uM), whereas BMS-303141 was substantially less active (17.46 and 22.07 uM). VCB1 similarly inhibited BTK inhibitor sensitive and resistant mantle cell lymphoma cell growth (IC₅₀, 0.28 and 0.278 uM), compared with BMS-303141 (30.5 and 37.01 uM). Multi-omics profiling revealed suppression of de novo lipogenesis, including ACACA, FASN, and PPARGC1B, together with extensive remodeling of triglyceride, phospholipid, cardiolipin, ceramide, and acylcarnitine species and increased expression of fatty-acid oxidation genes. VCB1 activated the integrated stress response (ISR), inducing ATF4, PPP1R15A, DDIT3, DDIT4 and SESN2, while disrupting purine and pyrimidine metabolism and reducing nucleotide biosynthetic genes, including CAD, DHODH, UCK2, and ATIC. VCB1 further activated an ACLY/ISR/CHAC1 axis associated with reduced GCLC/GCLM expression, glutathione depletion, and a decreased GSH/GSSG ratio, indicating impaired redox homeostasis. TKI-resistant cells exhibited distinct lipid-metabolic remodeling consistent with metabolic plasticity. VCB1 also altered immune-regulatory programs involving PDCD1, TIGIT, CD247, CD226, NFATC2, and inflammatory cytokines. Functionally, VCB1 induced cell cycle arrest and apoptosis.
Conclusions: ACLY represents an integrated metabolic and signaling vulnerability in lymphoma. VCB1 suppresses lymphoma growth across TKI-sensitive and resistant models by disrupting lipid and nucleotide metabolism, metabolic adaptation and ISR and redox homeostasis supporting ACLY inhibition as a therapeutic strategy for TKI-resistant lymphoma.