Oxaliplatin delivery via chitosan/vitamin E conjugate micelles for improved efficacy and MDR-reversal in breast cancer.

A bioinspired chitosan/vitamin E conjugate (Ch/VES, 1:4) was synthesized, optimized based on chitosan's molecular weight (15, 300 kDa), and was assembled to entrap oxaliplatin (OXPt). H NMR, infrared spectroscopy, chromatography, X-ray photoelectron spectroscopy, X-ray diffraction, drug release, hemolysis, and stability studies were performed to characterize OXPt@Ch/VES micelles. The therapeutic efficacy of the micelles was tested in vitro in ER+/PR+/HER2- and triple-negative sensitive/resistant breast cancer cells, MCF-7 and MDA-MB-231 via cellular uptake, cytotoxicity, nuclear staining, DNA fragmentation, mitochondrial membrane potential, ROS generation, apoptosis, and cell cycle assays and in vivo using 4T1(Luc)-tumor-bearing mice. OXPt@Ch/VES Ms exhibited decreased IC50 towards MCF-7, MDA-MB-231 (sensitive/resistant) than OXPt. OXPt@Ch/VES Ms caused extensive DNA damage, mitochondrial depolarization, apoptosis, and cell-growth arrest (G2/M). OXPt@Ch/VES Ms treatment retarded tumor growth significantly, prolonged survival, and decreased nephrotoxicity than OXPt. The OXPt@Ch/VES Ms could serve as a potential nanomedicine to overcome conventional OXPt-mediated drug resistance/nephrotoxicity in breast cancer.