PLGA Nanoplatform for the Hypoxic Tumor Delivery: Folate Targeting, Therapy, and Ultrasound/Photoacoustic Imaging.

Effective targeting of breast tumors is critical for improving therapeutic outcomes in breast cancer treatment. Additionally, hypoxic breast cancers are difficult to treat due to resistance toward chemotherapeutics, poor vascularity, and enhanced angiogenesis, which complicate effective drug delivery and therapeutic response. Addressing this formidable challenge requires designing a drug delivery system capable of targeted delivery of the anticancer agent, inhibition of efflux pump, and suppression of the tumor angiogenesis. Here, we have introduced Palbociclib (PCB)-loaded PLGA nanoparticles (NPs) consisting of chitosan-folate (CS-FOL) for folate receptor-targeted breast cancer therapy. The developed NPs were below 219 nm with a smooth, spherical surface shape. The entrapment efficiencies of NPs were achieved up to 85.78 ± 1.8%. Targeted NPs demonstrated faster drug release at pH 5.5, which potentiated the therapeutic efficacy of NPs due to the acidic microenvironment of breast cancer. In vitro cellular uptake study in MCF-7 cells confirmed the receptor-mediated endocytosis of targeted NPs. In vivo ultrasound and photoacoustic imaging studies on rats with hypoxic breast cancer showed that targeted NPs significantly reduced tumor growth and hypoxic tumor volume, and suppressed angiogenesis.