Paclitaxel and curcumin coadministration in novel cationic PEGylated niosomal formulations exhibit enhanced synergistic antitumor efficacy

BACKGROUND The systemic administration of cytotoxic chemotherapeutic agents for cancer treatment often has toxic side effects, limiting the usage dose. To increase chemotherapeutic efficacy while reducing toxic effects, a rational design for synergy-based drug regimens is essential. This study investigated the augmentation of therapeutic effectiveness with the co-administration of paclitaxel (PTX; an effective chemotherapeutic drug for breast cancer) and curcumin (CUR; a chemosensitizer) in an MCF-7 cell line. RESULTS We optimized niosome formulations in terms of surfactant and cholesterol content. Afterward, the novel cationic PEGylated niosomal formulations containing Tween-60: cholesterol:DOTAP:DSPE-mPEG (at 59.5:25.5:10:5) were designed and developed to serve as a model for better transfection efficiency and improved stability. The optimum formulations represented potential advantages, including extremely high entrapment efficiency (~ 100% for both therapeutic drug), spherical shape, smooth-surface morphology, suitable positive charge (zeta potential ~ + 15 mV for both CUR and PTX), sustained release, small diameter (~ 90 nm for both agents), desired stability, and augmented cellular uptake. Furthermore, the CUR and PTX kinetic release could be adequately fitted to the Higuchi model. A threefold and 3.6-fold reduction in CUR and PTX concentration was measured, respectively, when the CUR and PTX was administered in nano-niosome compared to free CUR and free PTX solutions in MCF-7 cells. When administered in nano-niosome formulations, the combination treatment of CUR and PTX was particularly effective in enhancing the cytotoxicity activity against MCF-7 cells. CONCLUSIONS Most importantly, CUR and PTX, in both free form and niosomal forms, were determined to be less toxic on MCF-10A human normal cells in comparison to MCF-7 cells. The findings indicate that the combination therapy of PTX with CUR using the novel cationic PEGylated niosome delivery is a promising strategy for more effective breast cancer treatment.