Cariporide Enhances the DNA Damage and Apoptosis in Acid-tolerable Malignant Mesothelioma H-2452 Cells

• Published in: Molecules and cells Vol. 40; no. 8; pp. 567 - 576
• Main Authors: Lee, Yoon-Jin, Bae, Jin-Ho, Kim, Soo-A, Kim, Sung-Ho, Woo, Kee-Min, Nam, Hae-Seon, Cho, Moon-Kyun, Lee, Sang-Han
• Format: Journal Article
• Language: English
• Published: United States Korean Society for Molecular and Cellular Biology 01.08.2017; 한국분자세포생물학회
• Subjects: Apoptosis - drug effects; Cell Cycle - drug effects; Cell Line, Tumor; Cell Proliferation - drug effects; Chromones - pharmacology; Culture Media; DNA Damage; Guanidines - pharmacology; Guanidines - therapeutic use; Humans; Hydrogen-Ion Concentration; Lung Neoplasms - drug therapy; Lung Neoplasms - pathology; Membrane Potential, Mitochondrial - drug effects; Mesothelioma - drug therapy; Mesothelioma - pathology; Mesothelioma, Malignant; Mitochondria - drug effects; Mitochondria - metabolism; Morpholines - pharmacology; Phosphorylation - drug effects; Proto-Oncogene Proteins c-akt - metabolism; Reactive Oxygen Species - metabolism; Sulfones - pharmacology; Sulfones - therapeutic use; Tumor Suppressor Protein p53 - metabolism; Up-Regulation - drug effects; 생물학; LY294002; cariporide; malignant mesothelioma; phosphatidylinositol-3-kinase; p53
• ISSN: 1016-8478; 0219-1032
• DOI: 10.14348/molcells.2017.0059

The Na /H exchanger is responsible for maintaining the acidic tumor microenvironment through its promotion of the reabsorption of extracellular Na and the extrusion of intracellular H . The resultant increase in the extracellular acidity contributes to the chemoresistance of malignant tumors. In this study, the chemosensitizing effects of cariporide, a potent Na /H -exchange inhibitor, were evaluated in human malignant mesothelioma H-2452 cells preadapted with lactic acid. A higher basal level of phosphorylated (p)-AKT protein was found in the acid-tolerable H-2452AcT cells compared with their parental acid-sensitive H-2452 cells. When introduced in H-2452AcT cells with a concentration that shows only a slight toxicity in H-2452 cells, cariporide exhibited growth-suppressive and apoptosis-promoting activities, as demonstrated by an increase in the cells with pyknotic and fragmented nuclei, annexin V-PE(+) staining, a sub-G /G peak, and a G /M phase-transition delay in the cell cycle. Preceding these changes, a cariporide-induced p-AKT down-regulation, a p53 up-regulation, an ROS accumulation, and the depolarization of the mitochondrial-membrane potential were observed. A pretreatment with the phosphatidylinositol-3-kinase (PI3K) inhibitor LY294002 markedly augmented the DNA damage caused by the cariporide, as indicated by a much greater extent of comet tails and a tail moment with increased levels of the p-histone H2A.X, p-ATM , p-ATR , p-CHK1 , and p-CHK2 , as well as a series of pro-apoptotic events. The data suggest that an inhibition of the PI3K/AKT signaling is necessary to enhance the cytotoxicity toward the acid-tolerable H-2452AcT cells, and it underlines the significance of proton-pump targeting as a potential therapeutic strategy to overcome the acidic-microenvironment-associated chemotherapeutic resistance.