In vitro Characterization of the Rapid Cytotoxicity of Anticancer Peptide HPRP-A2 through Membrane Destruction and Intracellular Mechanism against Gastric Cancer Cell Lines

In this study, HPRP-A2, a synthetic 15-mer cationic peptides with all D-amino acids, effectively inhibited the survival of gastric cell lines in a dose-dependent manner. Gastric tumor cells killing by HPRP-A2 involves a rapid collapse of the membrane integrity and intracellular pathways. Propidium iodide (PI) and lactate dehydrogenase (LDH) assays demonstrated that one-hour treatment with HPRP-A2 led to membrane permeability changes of BGC-823 cells in a dose-dependent manner. Moreover, HPRP-A2 induced apoptosis in BGC-823 cells involves a marked increase in generation of reactive oxygen species (ROS),caspase-3, -8 and -9 activation, a reduction of mitochondrial membrane potential (MMP), and cell cycle arrest in G1 phase. In addition to its inherent cytotoxicity, HPRP-A2 synergized strongly with doxorubicin (DOX) to enhance the efficacy of killing gastric tumor cells in vitro. We believe that HPRP-A2 with all D-amino acids could be a potent candidate of anticancer therapeutics, especially in combination therapy.