The Inhibitory Effects of Tumour Necrosis Factor-Related Apoptosis-Inducing Ligand/Vitipofen-Loaded Bacterial Outer Vesicles on Oral Squamous Cell Carcinoma Cells

The tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) triggers the apoptosis of tumour cells. According to recent studies, a number of malignant tumours show resistance to TRAIL due to activation and overexpression of the Yes-associated protein (YAP) signal pathway. Objective: To construct a novel type of bacterial outer membrane vesicles (BEVs) based delivery system to inhibit the growth of oral squamous cell carcinoma (OSCC) cells. Methods: BEVs loaded with verteporfin (VPF)/TRAIL (BEVs–TRAIL/VPF) was prepared by ultracentrifugation and filtration. The expression of TRAIL was verified by BCA and transmission electron microscopy. High-performance liquid chromatography was used in determining the drug loading of VPF and drawing a release curve in vitro. MTT and Western blot were adopted to reveal the anti-tumour activity of BEVs–TRAIL/VPF in vitro. Results: The BEVs–TRAIL/VPF particles appeared round by having a well uniform size distribution of approximately 100 nm in diameter. BEVs–TRAIL and VPF were capable of dose-dependently inhibiting the proliferation of SCC25 cells, and the best inhibitory effect appeared at ratios of 5:1–10:1. At 100:5–100:15 ratios, BEVs–TRAIL/VPF had a lower IC50 than free BEVs–TRAIL+VPF group (p<0.05), indicating a more efficacious inhibitory effect. The high inhibitory effect of BEVs–TRAIL/VPF on squamous cell carcinoma cells is partially associated with the activation of caspase 3, Bax, BCL2, mTOR, p-mTOR and YAP. Conclusion: the administration of TRAIL/VPF in a fixed ratio by BEVs displays a profound inhibitory effect on OSCC cells, providing a novel approach for the treatment of multidrug-resistant OSCC.