Theranostic Potential of Copper-64 ATSM Targeting MTHFD2: An In Silico Perspective on Hypoxia-Selective Imaging and Therapy.

Abstract

Hypoxia is a hallmark of the tumor microenvironment, leading to metabolic reprogramming and therapeutic resistance. The enzyme methylenetetrahydrofolate dehydrogenase 2 (MTHFD2) supports hypoxia adaptation, making it an attractive target for cancer treatment. Copper-64 diacetyl-bis(N4-methylthiosemicarbazone) (⁶⁴Cu-ATSM) exhibits selective hypoxia uptake, positioning it as a promising theranostic agent for imaging and treating hypoxic tumors. In this study, we employed molecular docking and molecular dynamics (MD) simulations to evaluate the binding, stability, and dynamic behavior of ⁶⁴Cu-ATSM within the MTHFD2 active site. Docking analysis revealed strong binding affinity (ΔG_bind = -7.91 kcal/mol) with stable hydrogen bonding to key residues. MD simulations, assessed via root mean square deviation (RMSD), root mean square fluctuation (RMSF), radius of gyration (Rg), radial distribution function (RDF), solvent-accessible surface area (SASA), dynamic cross-correlation maps (DCCM), and 2D principal component analysis (2D-PCA), confirmed ligand stability. MM-PBSA and per-residue decomposition analyses identified ARG43, TYR84, ASN87, LYS88, GLN132, GLY310, GLY313, and PRO314 as key contributors to ligand stabilization. These findings support ⁶⁴Cu-ATSM as a potential MTHFD2-targeting theranostic agent. However, in vitro and in vivo studies are needed to validate its therapeutic efficacy, pharmacokinetics, and clinical relevance for hypoxia-selective cancer therapy.