Black Phosphorus Nanosheets Induce Ferroptosis in Oral Squamous Cell Carcinoma via PI3K-AKT-SREBP1 Signaling Pathway-Mediated Lipogenesis

Oral squamous cell carcinoma (OSCC) presents significant therapeutic challenges due to chemoresistance and limited treatment modalities. Black phosphorus nanosheets (BPNSs), a novel two-dimensional nanomaterial, have shown promising antitumor effects. However, their role in inducing ferroptosis in OSCC and the underlying mechanisms remain to be elucidated. In this study, BPNSs were prepared via liquid-phase exfoliation, and their effects on the OSCC CAL-27 cells were subsequently evaluated. In vitro, BPNSs dose-dependently inhibited CAL-27 cell proliferation, induced G2/M phase arrest, and triggered ferroptosis, indicated by increased intracellular Fe²⁺, ROS, and lipid peroxidation, along with decreased glutathione (GSH) levels and altered expression of ferroptosis-related proteins (ACSL4, NCOA4, and GPX4). These effects were attenuated by ferroptosis inhibitor ferrostatin-1. In vivo, BPNSs suppressed CAL-27 xenograft growth without systemic toxicity, with elevated tumor malondialdehyde (MDA) and Fe²⁺ confirming ferroptosis. Mechanistic studies indicated that BPNSs inhibited the PI3K-AKT pathway, leading to the downregulation of <i>SREBP1</i>. Overexpression of <i>SREBP1</i> attenuated BPNS-induced ferroptosis, confirming its critical role. These findings suggest that BPNSs induce ferroptosis in OSCC via the PI3K-AKT-SREBP1 signaling pathway, providing a novel therapeutic strategy for OSCC treatment.