The hidden potential of solasonine: Targeting non-small cell lung cancer (NSCLC) metastasis through GATM and Smad2 pathways

Purpose To study the pharmacological effects of solasonine (Sol) in inhibiting non-small cell lung cancer (NSCLC) metastasis. Methods The pharmacological effects of solasonine were examined in vitro by continuous induction of NSCLC cells by no treatment, or TGF-β, or creatine. Cell migration and invasion were assessed via wound healing and transwell assays, and the levels of epithelial-mesenchymal transition (EMT) markers were determined using immunofluorescence and Western Blot. Solasonineʼs ability to bind to TGF-β and creatine transferases and isoenzymes was assessed by TCGA, KMPLOT database, cellular thermal shift assay (CETSA), and molecular docking assay. In vivo , two types of NSCLC cells were injected into mice using the tail vein. Solasonineʼs effect on tumor metastasis was determined using in vivo fluorescent probes, hematoxylin-eosin staining assay, and immunofluorescence. Results Unlike traditional therapies targeting TGF-β receptors, Sol was shown to inhibit NSCLC metastasis through a novel mechanism independent of TGF-β signaling. Creatine was found to promote NSCLC metastasis in vitro by enhancing cell migration, invasion, and EMT-related protein expression, and in vivo by increasing metastasis to the liver. These effects were mediated by the activation of Smad2 phosphorylation and EMT independently of TGF-β. Sol effectively counteracted these effects by targeting guanidinoacetate methyltransferase (GATM) with high binding affinity, thereby suppressing the TTK-mediated Smad2 pathway and significantly reducing metastasis to the lungs and liver, as confirmed by HE staining and fluorescence imaging. Conclusions This study identifies solasonine as a novel inhibitor of NSCLC metastasis, acting through the GATM and Smad2 pathways to counter creatine-induced metastasis. These findings underscore the potential of Sol as a therapeutic candidate for metastatic NSCLC.