ABSTRACT
BACKGROUND AND AIM: Iridium (Ir)-based complex is a potential antitumor ingredient, but its poor physicochemical properties such as hydrophobicity and low biocompatibility hamper further application. Liposome provides a potential delivery approach for improving the poor physicochemical property and reducing the side effects of antitumor drug. In this study, we aimed at incorporating Ir ([Ir(ppy)2(BTCP)]PF6) into liposomes to enhance the biocompatibility and sustained release of Ir for intravenous administration and to elucidate the mechanism in A549 cells. MATERIALS AND METHODS: Ir-loaded PEGylated liposomes (Lipo-Ir) were formulated by thin-film dispersion and ultrasonic method. Morphology, size distribution, and zeta potential of Lipo-Ir were examined by transmission electron microscopy (TEM) and Zetasizer. The released profile and biocompatibility were investigated by dialysis method and hemolysis test, respectively. Additionally, the cytotoxic activity and mechanism of Lipo-Ir and Ir inducing apoptosis in A549 cells were evaluated. RESULTS: Lipo-Ir can keep sustained release, excellent biocompatibility, and physical stability. The average particle size, polydispersity index, zeta potential, encapsulation efficiency, and drug loading are 112.57±1.15 nm, 0.19±0.02, -10.66±0.61 mV, 94.71%±3.21%, and 4.71%±0.41%, respectively. 3-(4,5-dimethylthiazole)-2,5-diphenltetraazolium bromide (MTT) assay show that Lipo-Ir and Ir display high cytotoxicity against selected cancer cells. Furthermore, the apoptotic features of morphology, depolarization of mitochondrial membrane potential, increase in the reactive oxygen species (ROS) levels, and disorder of Ca2+ homeostasis are observed after treating A549 cells with Ir and Lipo-Ir. Besides, Lipo-Ir can arrest the cell growth in G0/G1 phase. CONCLUSION: The studies demonstrate that Lipo-Ir can trigger apoptosis in A549 cells via ROS-mediated mitochondrial dysfunctions, and the biocompatible and sustained Lipo-Ir will be a promising drug delivery system.
Subject(s)
Drug Delivery Systems , Iridium/therapeutic use , Lung Neoplasms/drug therapy , Mitochondria/metabolism , A549 Cells , Animals , Antineoplastic Agents/pharmacology , Apoptosis/drug effects , Calcium/metabolism , Cell Cycle/drug effects , Cell Cycle Checkpoints/drug effects , Cell Proliferation/drug effects , Endocytosis/drug effects , Flow Cytometry , Humans , Inhibitory Concentration 50 , Iridium/pharmacology , Liposomes , Membrane Potential, Mitochondrial/drug effects , Mitochondria/drug effects , Rabbits , Reactive Oxygen Species/metabolismABSTRACT
In this study, folate-poly(ethylene glycol)3400-cholesterol conjugates (FA-PEG-Chol) were enzymatically synthesized in one step and incorporated into liposomes to prepare folate (FA)-functionalized liposomes for targeted drug delivery. The FA-functionalized liposomes loaded with betulinic acid (BA) (FA-L-BA) were prepared by thin lipid film method. The FA-L-BA was characterized by their morphology, particle size, zeta potential, encapsulation efficiency (EE), stability, cell cytotoxicity and cellular uptake. The average size of FA-L-BA was 222±8 nm. The spherical particles exhibited a negative electrical charge of -20.12±1.45 mV and high EE of 91.61%±1.16%. The liposomes were taken up selectively by HepG2 cells. FA-L-BA showed enhanced cytotoxicity (50% inhibitory concentration [IC50] =63.07±2.22 µg/mL) compared to nontargeted control normal liposomes loaded with BA (L-BA; IC50 =93.14±2.19 µg/mL) in HepG2 cells in vitro. In addition, FA-functionalized liposomes loaded with Ir-1 (FA-L-Ir-1) showed significantly higher cellular uptake in HepG2 cells compared to nontargeted control normal liposomes loaded with Ir-1 (L-Ir-1). This novel approach for the liposomes surface modified with FA by a one-step enzymatic amidation was expected to provide potential application as a drug carrier for active targeted delivery to tumor cells.
