Tubeimoside II potentiates anti-PD-1 therapy in NSCLC by increasing ferroptosis sensitivity and remodeling immune...

Tubeimoside Ⅱ (Tub Ⅱ), a pharmacologically active triterpenoid saponin purified from tubeimu, has exhibited promising antitumor properties, yet its molecular mechanisms in NSCLC remain incompletely understood.

Flow cytometry and immunofluorescence were used to detect the key immune cells. Multi-omics approach, integrating proteomic profiling, single-cell RNA sequencing, and bioinformatic analyses to uncover Tub Ⅱ' s mechanisms. Target engagement was validated via DARTS, CETSA, dual luciferase reporter, Chip-PCR, and ubiquitination assays. CRISPR-Cas9 of HERC2 and JAK2 was performed to dissect their roles in Tub II-mediated effects. Preclinical models included NSCLC xenografts, lung metastasis, PDOs, and PDXs.

Tub Ⅱ suppressed NSCLC cell growth by increased ROS generation, lipid peroxidation, ferrous iron content. Additionally, it enhanced antitumor T-cell immunity, promoted DC maturation and M1-like macrophage polarization, while reducing the immunosuppressive infiltration of MDSCs and Treg cells. Mechanistically, Tub Ⅱ bound to HERC2, impairing NCOA4 ubiquitination and degradation, thereby inducing ferritinophagy-dependent ferroptosis. Moreover, Tub Ⅱ targeted JAK2, inhibiting the JAK2/STAT3 pathway, leading to immune remodeling. Significantly, Tub Ⅱ synergized with chemotherapy, targeted therapy, and immunotherapy agents, enhancing antitumor efficacy in PDOs and PDXs.

Our study demonstrates that Tub Ⅱ triggers ferroptosis and reprograms the immune microenvironment in NSCLC by hyperactivating HERC2-mediated ferritinophagy and suppressing the JAK2/STAT3/PDL1/CXCL12 pathway. These results not only reveal a mechanism-driven strategy to target ferroptosis and potentiate PD-1 blockade but also highlight Tub Ⅱ as a multi-targeting natural compound with promising therapeutic potential for NSCLC.