Enhanced Antitumor Efficacy through an "AND gate" Reactive Oxygen-Species-Dependent pH-Responsive Nanomedicine...

Area of Science:

• Biomaterials Science
• Nanomedicine
• Cancer Therapeutics

Background:

• Solid tumors exhibit unique chemical microenvironments, including elevated reactive oxygen species (ROS) and low pH, distinct from healthy tissues.
• Conventional anticancer drug delivery often targets only one of these cues, limiting efficacy and potentially increasing side effects.
• Developing smart nanocarriers that respond to multiple tumor-specific stimuli is crucial for advanced cancer nanomedicine.

Purpose of the Study:

• To design and characterize novel "AND gate" multiresponsive (MR) block amphiphilic copolymers for targeted anticancer drug delivery.
• To exploit the synergistic effect of coexisting ROS and low pH in the tumor microenvironment for enhanced drug release.
• To evaluate the therapeutic efficacy and safety profile of Doxorubicin (DOX)-loaded MR polymersomes (MRPs) in preclinical models.

Main Methods:

• Fabrication of "AND gate" MR block copolymers with masked pH-responsive side chains activated by ROS.
• Self-assembly of Doxorubicin (DOX)-loaded nanosized MR polymersomes (MRPs) using microfluidics.
• In vitro characterization of ROS-dependent pH sensitivity and drug release kinetics under dual stimuli.
• In vivo evaluation of cardiac toxicity, tumor growth inhibition, and survival rates in tumor-bearing mice.

Main Results:

• The developed "AND gate" MRPs demonstrated exclusive pH sensitivity upon ROS exposure, enabling targeted drug release within the tumor microenvironment (pH 5.6-7.2).
• Accelerated DOX release was observed under the combined influence of ROS and low pH, confirming the "AND gate" mechanism.
• DOX-loaded "AND gate" MRPs significantly reduced cardiac toxicity compared to nonresponsive MRPs and free DOX.
• The optimized "AND gate" MRPs exhibited superior tumor growth inhibition and prolonged survival in mice compared to free DOX.

Conclusions:

• "AND gate" multiresponsive polymersomes represent a promising strategy for targeted anticancer drug delivery by leveraging multiple tumor-specific stimuli.
• The ROS-triggered demasking of pH-responsive elements allows for precise control over drug release in the tumor microenvironment.
• This approach enhances therapeutic efficacy while minimizing systemic toxicity, particularly cardiotoxicity associated with Doxorubicin.
• The findings highlight the importance of considering the complex chemical milieu of tumors for the rational design of next-generation cancer nanomedicines.