Rational design, synthesis and effective mechanism of sophoridine and matrine contains 2,3,4-triphenylpyridine derivatives as TopoⅠ inhibitors for the treatment of gastric carcinoma.

Sophoradine and its derivatives have demonstrated promising progress as topoisomerase I inhibitors in cancer therapy, yet their further development has been constrained by moderate activity. Meanwhile, the molecular target of its isomer, matrine, remains unclear. In this study, we designed and synthesized a series of sophoridine and matrine derivatives containing 2,3,4-triphenylpyridine moieties, aiming to develop more potent Topo I inhibitors. Their antiproliferative activities were evaluated in vitro against three cancer cell lines (C6, HepG2, HGC-27). Among them, the sophoridine derivative H4 and the matrine derivative K8 exhibited the strongest inhibitory effects, with IC50 values of 0.52 μM and 2.53 μM, respectively. Preliminary structure-activity relationship (SAR) analysis indicated that para-substituted 2,3,4-triphenylpyridine derivatives showed optimal activity. Subsequent DNA supercoiling assays revealed that most compounds could inhibit Topo I, with H4 demonstrating stronger inhibitory activity than K8. Furthermore, both H4 and K8 effectively suppressed the proliferation and migration of HGC-27 cells. Mechanistic studies demonstrated that H4 and K8 induced DNA damage in HGC-27 cells by inhibiting Topo I, leading to G0/G1 cell cycle arrest, overexpression and phosphorylation of p53 protein, and ultimately inducing apoptosis. Molecular docking experiments revealed distinct binding modes between H4/K8 and the target protein. In vivo studies demonstrated that the tumor growth inhibition (TGI) rates for sophoridine, matrine, H4, K8, and irinotecan were 19.3%, 9.7%, 45.3%, 36.6%, and 87.0%, respectively. H&E staining revealed that H4 and K8 exhibited a higher safety profile compared to irinotecan. Our findings suggest that Topo I may be a potential target of matrine, while H4 and K8 represent promising candidates for cancer therapy.