Fold-Stabilized Zn(II) Metallohelices Inhibit mTOR Signaling and Modulate the Tumor Microenvironment in Intrahepatic Cholangiocarcinoma

Abstract Water-stabilized metallohelices based on labile metal ions remain rare because of hydrolytic instability. Here, we report the design and synthesis of a unique class of optically pure, water-soluble, glycosylated Zn(II) metallohelix diastereomers that exhibit exceptional hydrolytic stability and potent, stereochemistry-dependent antiproliferative activity against intrahepatic cholangiocarcinoma (ICC). In an orthotopic, AKT/YAP-driven ICC mouse model, treatment with the lead compound Λ-7a produced significant tumor growth inhibition. Mechanistic studies revealed that treatment with Λ-7a induced cell cycle arrest and apoptosis, accompanied by suppression of PI3K-AKT-mTOR pathway signaling and reduced phosphorylation of downstream effectors. In addition, Λ-7a treatment was associated with reduced vascular and stromal marker staining and increased CD8+ T-cell and macrophage markers within the tumor microenvironment. Together, these results establish fold-stabilized Zn(II) metallohelices as a new class of metallodrugs exhibiting potent anti-ICC activity, suppression of AKT/mTOR pathway signaling, and treatment-associated changes in vascular, stromal, and immune-cell markers within the tumor microenvironment.