NPRA silencing overcomes TRAIL resistance via DR5 upregulation, anti-apoptotic factor inhibition, and NF-κB pathway suppression in lung cancer.

Lung cancer remains the leading cause of cancer-related deaths globally. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) shows promise for cancer treatment by rapidly inducing tumor apoptosis, but recombinant TRAIL (rTRAIL) failed clinically due to the widespread TRAIL resistance. Extracellular vesicle-delivered TRAIL (EV-T) has stronger apoptosis-inducing activity than rTRAIL. Moreover, natriuretic peptide receptor A (NPRA), overexpressed in multiple solid tumors, is a potential therapeutic target, yet its role in modulating TRAIL sensitivity remains unclear. Herein we propose delivering NPRA-targeting siRNA (siNPR1) via EV-T to reverse TRAIL resistance for efficient lung cancer therapy. First, EV-Ts were produced by previously established TRAIL-expressing mesenchymal stem cells (MSCs). Then, siNPR1 molecules were encapsulated into EV-Ts via ultrasonic loading to fabricate the composite nanotherapeutic siNPR1@EV-T. EV-T encapsulation and delivery of siNPR1 enabled efficient knockdown of NPRA and synergistically enhanced TRAIL-mediated apoptosis in lung cancer cells, with minimal cytotoxicity toward normal MSCs. Mechanistic studies revealed that the synergistic apoptosis induction is associated with concomitant upregulation of death receptor 5 (DR5) and downregulation of multiple anti-apoptotic regulators, including cFLIP, MCL-1, BCL-2, XIAP, and cIAP-1, as well as suppression of EGFR/AKT/nuclear factor-kappa B (NF-kappaB) pathway. Notably, siNPR1@EV-T therapy suppressed tumor cell proliferation, induced robust apoptosis, and thus eradicated TRAIL-resistant tumor growth in a murine A549 xenograft tumor model. Collectively, the siNPR1@EV-T formulation represents an innovative strategy for overcoming TRAIL resistance and potentially constitutes a highly effective therapy against lung cancer.