Tumor Microenvironmental Stimuli-Responsive Linear-Dendritic Polymeric Conjugate as Potential Nanomedicine

Area of Science:

• Polymer Chemistry
• Nanomedicine
• Drug Delivery Systems

Background:

• Developing advanced drug delivery systems is crucial for effective cancer therapy.
• Tumor microenvironment-responsive materials offer targeted drug release, minimizing systemic toxicity.
• Linear-dendritic polymers present unique architectures for nanocarrier design.

Purpose of the Study:

• To synthesize and characterize a tumor microenvironment-responsive, linear-dendritic polymer-doxorubicin conjugate.
• To evaluate the self-assembly, drug release kinetics, and in vitro/in vivo anticancer efficacy of the developed nanomedicine.
• To assess the safety profile of the nanomedicine in a preclinical cancer model.

Main Methods:

• Two-step reversible addition-fragmentation chain transfer (RAFT) polymerization was employed to synthesize the poly[N-(2-hydroxypropyl) methacrylamide] (polyHPMA)-based copolymer-doxorubicin conjugate (pHPMA-block-pDendron-DOX).
• The conjugate self-assembled into nanoparticles (NPs) incorporating a tumor-cleavable Gly-Phe-Leu-Gly (GFLG) peptide and a pH-sensitive hydrazone bond.
• In vitro cytotoxicity assays using 4T1 cells and in vivo studies in a 4T1 murine breast cancer xenograft model were conducted.

Main Results:

• The synthesized pHPMA-block-pDendron-DOX conjugate formed stable nanoparticles that exhibited cathepsin B- and pH-responsive drug release.
• Internalization via endocytosis pathways led to significant cytotoxic effects on 4T1 cancer cells.
• Enhanced doxorubicin accumulation at the tumor site and promising anti-cancer effects were observed in vivo, with significantly reduced side effects.

Conclusions:

• The linear-dendritic polymer conjugate successfully self-assembled into a tumor-responsive nanomedicine for targeted doxorubicin delivery.
• The developed nanomedicine demonstrated potent anticancer activity and an improved safety profile, highlighting its potential as an efficient and safe therapeutic agent.