Chitosan-Based Nanoparticles for Twist1 Knockdown in 4T1 Cells.

Bone metastasized breast cancer reduces the quality of life and median survival. Targeted delivery of twist1-siRNA using nanoparticles (NPs) is a promising strategy to overcome current limitations in treating such metastatic breast cancers. This research evaluates two types of chitosan (CHI)-based NPs for the delivery of twist1-siRNA. Alendronate conjugated PEG functionalized chitosan (ALD-PEG-CHI) NPs are developed for active targeting while PEG functionalized CHI (mPEG-CHI) NPs are fabricated for passive targeting. The size of twist1-siRNA-loaded NPs is below 70 nm and the zeta potential is near neutral for both types of NPs. Based on gel retardation assay, complete encapsulation of twist1-siRNA is achieved in both NP systems. The ALD-PEG-CHI-siRNA and mPEG-CHI-siRNA NPs display serum protection for 6 and 4 h, respectively, compared to the immediate degradation of naked twist1-siRNA. The NPs can knockdown twist1 in 4T1 cells as demonstrated through protein expression as well as by phenotypic change in directional cell migration by wound healing assay. Overall, these in vitro results illustrate the potential of the NPs as an effective therapeutic system for bone metastasized breast cancer.