Lysosome-oriented, dual-stage pH-responsive polymeric micelles for β-Lapachone delivery

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Oncology

Background:

• Beta-lapachone (β-lap) is a potent anticancer agent activated by NQO1, an enzyme overexpressed in various cancers.
• Limitations of current β-lap formulations include rapid clearance and side effects, hindering clinical application.
• Novel drug delivery systems are needed to overcome these challenges and enhance β-lap efficacy.

Purpose of the Study:

• To develop and characterize dual pH-responsive polymer micelles for targeted β-lap delivery.
• To investigate the pH-triggered release kinetics and intracellular behavior of β-lap-loaded micelles.
• To evaluate the NQO1-dependent cytotoxicity of the developed nanocarrier in lung cancer cells.

Main Methods:

• Synthesis of β-lap prodrugs utilizing pH-sensitive linkages, with aryl imine proving optimal.
• Conjugation of the β-lap prodrug to ultra pH-sensitive (UPS) polymers to form micelles (M-P).
• In vitro release studies at varying pH levels (7.4, 6.5, 5.0) and intracellular distribution analysis in A549 lung cancer cells.

Main Results:

• The aryl imine linkage demonstrated efficient β-lap release at acidic pH (100% at pH 5.0).
• M-P micelles exhibited dual-stage pH responsiveness, with rapid dissociation and β-lap release at pH < pHt.
• High β-lap loading (8.3%) and sustained release above pHt (14.9% in 72h) were achieved, with preferential lysosomal accumulation.
• NQO1-dependent cytotoxicity of M-P micelles was comparable to free β-lap in A549 cells.

Conclusions:

• Dual-stage ultra pH-responsive β-lap prodrug micelles offer a promising nanotherapeutic strategy.
• Lysosome-oriented drug release enhances targeted delivery and efficacy in NQO1+ cancers.
• This approach holds potential for treating lung and other NQO1-overexpressing tumors.