# Chitosan‐Based Nanoparticles for Twist1 Knockdown in 4T1 Cells

## TL;DR

This study explores using chitosan-based nanoparticles to deliver siRNA targeting the twist1 gene in breast cancer cells, potentially improving treatment for bone metastases.

## Contribution

The novelty lies in developing both passive and active targeting chitosan-based nanoparticles for twist1 gene silencing in 4T1 cells.

## Key findings

- Twist1-siRNA-loaded nanoparticles effectively knock down twist1 gene expression in 4T1 cells.
- Nanoparticles show delayed siRNA degradation in serum compared to naked siRNA.
- Wound healing assays confirm phenotypic changes due to twist1 knockdown.

## Abstract

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.

Modified chitosan nanoparticles have the potential for passive and active siRNA delivery to different tumors. This study evaluates twist1‐siRNA‐loaded pegylated chitosan and alendronate‐conjugated pegylated chitosan nanoparticles for twist1 gene silencing in 4T1 cells. Twist1 gene silencing is confirmed through delayed wound healing and reduced twist1 protein expression. This shows the potential of these nanoparticles for bone metastasized breast cancer.