Investigating the Impact of Optimized -Cinnamic Acid-Loaded PLGA Nanoparticles on Epithelial to Mesenchymal Transition in Breast Cancer.

Purpose: To design and optimize -cinnamic acid-loaded PLGA nanoparticles (CIN-PLGA-NPs) and assess its inhibitory effect on epithelial-mesenchymal transition (EMT) in triple-negative breast cancer.

Methods: The quality by design approach was used to correlate the formulation parameters (PLGA amount and Poloxamer188 concentration) and critical quality attributes (entrapment efficiency percent, particle size and zeta potential). Design of CIN-PLGA-NPs formulations was done based on central composite response surface design and formulated by nanoprecipitation method. In addition, the optimized CIN-PLGA-NPs formulation was further evaluated for morphology using transmission electron microscopy and in vitro dissolution test. The cytotoxicity of CIN-PLGA-NPs optimized formula in comparison to the free -cinnamic acid (CIN-Free) was investigated in vitro using MDA-MB-231, triple-negative breast cancer cells, followed by scratch wound assay for evaluating the impact on the migratory potential of MDA-MB-231 cells. In vivo antitumor activity was evaluated using Ehrlich ascites carcinoma solid tumor animal model where tumor volumes were measured at different time points and necrotic/apoptotic indices were estimated in tumor sections. EMT markers, E- and N-cadherin, were assessed in solid tumors as well.

Results: The optimized formulation showed entrapment efficiency of 76.98%, particle size of 186.3 nm with a smooth spherical surface and zeta potential of -28.47 mV indicating its stability. Furthermore, CIN-PLGA-NPs optimized formula released 60.8±1.89% of the total CIN-Free within 24 hours compared to 29±1.25% of the raw CIN-Free indicating improved dissolution rate. The optimized formula showed superior cytotoxicity on MDA-MB-231 cells compared to its free counterpart as well as increased wound closure percentage along with reduced tumor size in mice and increased necrotic and apoptotic indices. Tumor levels of E-cadherin and N-cadherin were indicative of EMT inhibition.

Conclusion: Our findings proved the capability of PLGA nanoparticles in loading -cinnamic acid in addition to enhancing its antitumor efficacy in triple-negative breast cancer possibly via inhibiting EMT.