Matrix metalloproteinase 2-responsive micelle for siRNA delivery

Area of Science:

• Biomaterials Science
• Nanotechnology
• Cancer Therapeutics

Background:

• Systemic delivery of small interfering RNA (siRNA) to cancer cells is a significant challenge in developing siRNA-based drugs.
• Effective siRNA delivery requires vehicles with prolonged blood circulation, tumor accumulation, and efficient cancer cell internalization for gene silencing.

Purpose of the Study:

• To develop and evaluate a core-shell Micelleplex delivery system for systemic siRNA administration in cancer therapy.
• To demonstrate the system's ability to achieve targeted delivery, enhanced cellular uptake, and effective gene silencing in breast tumors.

Main Methods:

• Fabrication of a core-shell Micelleplex using block copolymers including poly(ethylene glycol) (PEG), an MMP-2-degradable peptide (PLG*LAG), a cell-penetrating peptide (polyarginine r9), and poly(ε-caprolactone) (PCL).
• In vitro and in vivo evaluation of the Micelleplex for blood circulation time, tumor accumulation, and MMP-2-triggered PEG layer shedding.
• Assessment of enhanced cellular uptake mediated by the exposed cell-penetrating peptide and evaluation of siRNA efficacy against Polo-like kinase 1 in breast tumor models.

Main Results:

• The Micelleplex demonstrated prolonged circulation and significant accumulation at tumor sites.
• Tumor-specific matrix metalloproteinase 2 (MMP-2) triggered the shedding of the PEG layer, exposing the polyarginine r9 peptide.
• The exposed peptide enhanced cellular uptake, leading to efficient gene silencing and significant inhibition of breast tumor growth.

Conclusions:

• The developed core-shell Micelleplex is a promising system for systemic siRNA delivery in cancer therapy.
• The stimuli-responsive design enhances tumor targeting and cellular internalization, leading to improved therapeutic outcomes.