Polymeric Micellar Nanoparticles Enable Image-guided Drug Delivery in Solid Tumors

Area of Science:

• Nanotechnology and Materials Science
• Cancer Biology and Therapeutics
• Biomedical Imaging

Background:

• Solid tumors exhibit elevated reactive oxygen species (ROS) and express cyclooxygenase-2 (COX-2).
• Targeted drug delivery and real-time monitoring are crucial for effective cancer therapy.
• Developing responsive nanocarriers for simultaneous drug delivery and imaging remains a challenge.

Purpose of the Study:

• To develop a nanotechnology for co-delivery of chemocoxib A (CA) and a COX-2 targeted, ROS-activatable pro-fluorescent probe (fluorocoxib Q, FQ).
• To enable real-time visualization of drug delivery and COX-2 expression in solid tumors.
• To assess the efficacy of ROS-sensitive drug release and tumor targeting in vitro and in vivo.

Main Methods:

• Synthesis of FQ and CA, followed by co-encapsulation into di-block PPS₁₃₅-b-POEGA₁₇ copolymer nanoparticles (FQ-CA-NPs).
• Characterization of FQ-CA-NPs for size, zeta potential, and ROS-dependent cargo release.
• In vitro assessment of FQ-CA-NP uptake and cargo release in 4T1 cancer cells and primary human mammary epithelial cells (HMECs).
• In vivo evaluation of FQ-CA-NP delivery to orthotopic mammary tumors in mice using fluorescence imaging and LC-MS/MS analysis.

Main Results:

• FQ-CA-NPs exhibited a hydrodynamic diameter of 109.2 ± 4.1 nm and a zeta potential of -1.59 ± 0.3 mV.
• ROS-dependent cargo release was observed in 4T1 cells, leading to decreased breast cancer cell growth without affecting HMECs.
• In vivo imaging confirmed NP accumulation in mammary tumors, with LC-MS/MS detecting both CA and FQ in tumor tissues.
• No significant NP-derived fluorescence was detected in healthy organs.

Conclusions:

• Co-encapsulation of FQ and CA into PPS₁₃₅-b-POEGA₁₇ nanoparticles provides a viable strategy for ROS-sensitive drug release.
• The FQ-CA-NPs enable targeted delivery and COX-2-mediated visualization of solid tumors, guiding cancer therapy.
• This nanotechnology holds promise for improving the efficacy and monitoring of cancer treatments.