Tailoring diblock copolymers for efficient siPLK1 delivery and enhanced gene therapy of orthotopic osteosarcoma

Area of Science:

• Biomaterials Science
• Nanotechnology
• Oncology

Background:

• Osteosarcoma (OS) is a bone cancer with high metastatic potential.
• Effective siRNA delivery systems are crucial for OS treatment but face challenges in safety and efficacy.
• Current delivery methods struggle in orthotopic models, highlighting the need for advanced nanocarriers.

Purpose of the Study:

• To develop a precisely engineered diblock copolymer for efficient and targeted siRNA delivery in osteosarcoma.
• To evaluate the in vitro and in vivo performance of the copolymer-siRNA complex for osteosarcoma therapy.
• To assess the anti-tumor and anti-metastasis efficacy of the novel therapeutic system in a metastatic OS model.

Main Methods:

• Synthesized a diblock copolymer (PEG₁₁₃-b-P(AAPBA₂₀-co-DMAPMA₂₀)) with specific functional units for siRNA binding, endosomal escape, and OS targeting.
• Formulated well-defined nanoparticles (NPs) capable of efficient endocytosis.
• Utilized siPLK1 as the therapeutic RNA payload.
• Evaluated NP performance in vitro for gene silencing and in vivo in an orthotopic 143B OS model for anti-tumor and anti-metastasis effects.

Main Results:

• The designed copolymer formed NPs that facilitated efficient endocytosis, endosomal escape, and siRNA release.
• Achieved 83.9% in vitro PLK1 gene silencing, significantly higher than the commercial Lipo3000 (49.3%).
• Demonstrated a superior anti-tumor effect (74.6% inhibition rate) and anti-metastasis activity in a highly metastatic orthotopic OS model.

Conclusions:

• The novel diblock copolymer is a promising platform for developing safe and effective siRNA therapeutics for osteosarcoma.
• The targeted delivery system overcomes key challenges in siRNA delivery, showing significant therapeutic potential.
• This approach offers a viable strategy for combating OS local destruction and metastasis.