Abstract
Background/Objectives: Non-small cell lung cancer (NSCLC) accounts for about 85% of lung cancers and is a leading cause of cancer-related deaths worldwide. Pharmacological targeting of the p53–MDM2 interaction to activate wild-type p53 is a promising strategy for treating NSCLC that retain functional p53 (approximately 50% of all cases). Methods: We screened 33 ethnomedicinal Vietnamese plant extracts for their anticancer effects using p53-expressing and p53-null NSCLC cell models, as well as two non-cancerous cell lines for control. We used an array of different experimental approaches including NMR spectroscopy; molecular docking; an MTT test; cell cycle analysis; apoptosis analysis; wound healing, migration, and invasion assays; Real-Time PCR; immunoblotting; and Seahorse energy profiling to characterize and study the effects of these bioactive compounds on NSCLC cells. Results: Ethanol extract of Zanthoxylum nitidum stems and twigs demonstrated potent and selective activity by inducing p53-dependent cell cycle arrest and apoptosis. Phytochemical analysis identified several benzophenanthridine alkaloids as active constituents. Molecular docking revealed their strong in silico binding to MDM2. Notably, nitidine was the most promising compound among the molecules tested. Unlike nutlin, but similar to SP141 (two well-known MDM2 inhibitors), nitidine strongly stabilized p53 while concomitantly attenuating MDM2 at the protein level. Surprisingly, this effect was p53-independent. Additionally, nitidine suppressed the EMT master regulator Snail, and hence disrupted cellular bioenergetics and inhibited migration and invasion of NSCLC cells. Conclusions: Our findings identify Z. nitidum and nitidine as promising sources for developing novel MDM2-targeting therapeutics against NSCLC irrespective of the p53 status.