Local and Systemic Delivery of the BimS Gene Nano-Complex for Efficient Oral Squamous Cell Carcinoma Therapy.

Purpose: Oral squamous cell carcinoma (OSCC) is the most common type of oral cancer, with more than 300,000 new cases annually. Despite advances in existing treatments, including surgery, radiation, chemotherapy, and immunotherapy, the overall survival and prognosis have remained poor. However, gene therapy based on non-viral vectors provides new ideas for the treatment of OSCC. Here, we aimed to prepare and describe the synthesis, biosafety, and preclinical efficacy of DOTAP-mPEG-PCL (DMP) in OSCC gene therapy.

Methods: We prepared a nano-sized hybrid cationic micelle DMP. DMP micelles were prepared by self-assembling cationic lipid DOTAP and mPEG-PCL polymer. We evaluated the characteristics of this cationic micelle in vitro. Combined with encoding the apoptosis-inducing BimS gene, we established the DMP/phBimS complex and evaluated its anti-tumor effect in vitro. We also established a mouse tongue xenograft model to evaluate the antitumor effect of the DMP/phBimS complex in vivo through local and systemic administration prospectively.

Results: The DMP cationic micelle is spherical in shape, with an average diameter of 28.32 ± 3.56 nm and an average zeta potential of 43.43 ± 0.82 mV. By activation of lipid raft-mediated endocytosis caveolin-mediated endocytosis, DMP could efficiently deliver plasmid into SCC15 cells (efficiency: 52.07% ± 1.63%), with an ideal biosecurity. When loaded by plasmid encoding the apoptosis-inducing BimS gene, the DMP/phBimS complex exhibited an obvious anti-proliferation effect of SCC15 in vitro through the apoptosis pathway (33.9% ± 2.62% apoptosis rate). By local administration, the DMP/phBimS complex showed ideal anti-tumor properties in the nude mouse tongue xenograft model, with an average tumor inhibition rate of 65.66%. Furthermore, through systematic administration, the DMP/phBimS complex obviously inhibited OSCC growth, with an average inhibition rate of 45.63% (DMP/phBimS) and an appropriate biocompatibility.

Conclusion: The DMP/phBimS complex is an optional effective option for suicide gene therapy for OSCC.