Liposomes containing cholesterol and mitochondria-penetrating peptide (MPP) for targeted delivery of antimycin A to A549 cells

Abstract • Mitochondria are exclusively employed to produce energy required for the vital metabolic functions of the cell. However, mitochondria also play a key role in mammalian cell death. Dissipation in the mitochondria membrane potential causes cell death. Therefore, in cancer therapy, mitochondria are a novel target. Herein, we developed a nano-formulation of Antimycin A specifically targeted towards mitochondria and lung cancer; A549 cell. The liposomes were prepared using cholesterol and a mitochondria-penetrating peptide (MPP) having a phenylalanine-arginine-phenylalanine-lysine (FRFK) peptide sequence. The FRFK peptide was synthesized using solid phase peptide synthesis (SPPS) and contained cholesterol in the N-terminal end of the phenylalanine (Chol-FRFK). The synthesized material was confirmed using 1H NMR, Fourier transform infrared spectroscopy (FT-IR) and matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI TOF/MS). 1,2-Dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) and Chol-FRFK, at a molar ratio of 1:1, were used for liposomal (Chol-FRFK/D) formulations; the sizes of the liposomes were confirmed using dynamic light scattering (DLS). Cytotoxicity was evaluated in A549 cells. Cellular uptake and mitochondria targeting were confirmed by flow cytometry and confocal microscopy, respectively. Antimycin A, a hydrophobic and mitochondrial electron transporter inhibitor was encapsulated into the Chol-FRFK/D liposomes. Our results indicate that Chol-FRFK/D liposomes may potentially be used for the nano-formulation of cytotoxic drugs and enhancing their bioavailability in cancer therapy.