Targeted co-delivery of curcumin and doxorubicin by citric acid functionalized Poly (ε-caprolactone) based micelle in MDA-MB-231 cell.

This study aimed to design an effective targeted combination of doxorubicin (Dox)-Curcumin (Cur) delivery system to eradicate the MDA-MB231 cell line. A novel biodegradable poly ε-Caprolactone-co-maleic anhydride-graft-citric acid copolymer micelle (PCL-co-P(MA-g-CA)) was synthesized through thiolen radical copolymerization and ring-opening polymerization. The unique micelle structure allowed simultaneous loading of hydrophilic Dox and hydrophobic Cur with a loading efficiency of above 98 % for each drug. The physicochemical characterization of copolymeric micelle was analyzed by HNMR, CNMR, FTIR, DSC, CMC, DLS and SEM. The in vitro cytotoxicity was assessed by MTT assay, cell cycle analysis, annexin V-FITC apoptosis, qRT-PCR and western blot. The final obtained micelles with critical micelle concentration (CMC) of 0.5 μg/mL, and particle size and surface charge was 60 nm and -14.1 mV, respectively. Beside the fast uptake of designed micelle, Dox@Cur loaded micelle showed a synergistic effect with the combination index (CI) value of below 1. Our results revealed that this novel engineered combinatorial micelle induced apoptosis (96 %) which was proved by annexin V and cell cycle. qRT-PCR and western blot assays demonstrated involvement of intrinsic apoptosis pathways in the genetic and protein levels. Finally, the penetration of Dox@Cur loaded micelle was evaluated by 3D in vitro tumor formation. Our findings showed the penetration behavior of micelles is in a concentration-dependent manner. In conclusion, combinational therapy by using Dox and Cur nano-formulation has boosted the cytotoxicity in MDA-MB231 cells by promoting the apoptotic response.