Preliminary study on intravesical instillation of IL-12 mRNA lipid nanoparticles for the treatment of bladder cancer

Purpose: The present study aims to investigate the feasibility and therapeutic potential of intravesically administered interleukin-12 mRNA-loaded lipid nanoparticles (IL-12 mRNA LNPs) for treatment of orthotopic bladder cancer. Methods: Fluc-mRNA LNPs and IL-12 mRNA LNPs were prepared using microfluidic technology and characterized in terms of particle size, zeta potential, encapsulation efficiency, and stability. The in vivo transfection efficiency of the Fluc-mRNA LNPs were assessed by bioluminescence imaging. The antitumor efficacy of IL-12 mRNA LNPs was valuated in orthotopic bladder cancer mice models which were established with Luc-MB49 cells. Results: Fluc-mRNA LNPs and IL-12 mRNA LNPs were successfully prepared via microfluidics, which had uniform particle size (101.6 nm and 104.4 nm), near-neutral surface charge (-3.39 mV and -8.34 mV), high encapsulation efficiency (89.01% and 98.87%), and good stability. Efficient intravesical transfection and robust protein expression were confirmed in mouse bladders using an in vivo bioluminescence imaging. In orthotopic bladder cancer–bearing mice, intravesical instillation of IL-12 mRNA LNPs significantly inhibited tumor growth. Conclusions: Intravesical delivery of IL-12 mRNA LNPs represents an effective and promising strategy for local immunotherapy of bladder cancer. These findings provide experimental evidence supporting the potential clinical translation of mRNA-LNPs-based intravesical regimens for the treatment of bladder cancer.