RESUMEN
BACKGROUND: The discovery of novel phytochemicals represents a reasonable approach to fight malignancies, especially those which are resistant to standard chemotherapy. PURPOSE: We evaluated the cytotoxic potential of a naturally occurring N-acetylglycoside of oleanolic acid, aridanin, on 18 cancer cell lines, including sensitive and drug-resistant phenotypes mediated by P-glycoprotein, BCRP, p53 knockout, deletion-mutated EGFR, or BRAF mutations. Furthermore, metastasizing B16/F10 cells, HepG2 hepatocarcinoma and normal AML12 hepatocytes were investigated. The mechanisms of aridanin-induced cell death was further investigated. METHODS: The resazurin reduction assay (RRA) was applied to evaluate the cytotoxicity, autophagy, ferroptotic and necroptotic cell death. CCRF-CEM leukemia cells were used for all mechanistic studies. A caspase-Glo assay was applied to evaluate the caspase activities. Flow cytometry was applied for the analyses of cell cycle (PI staining), apoptosis (annexin V/PI staining), mitochondrial membrane potential (MMP; JC-1) and reactive oxygen species (ROS; H2DCFH-DA). RESULTS: Aridanin and doxorubicin (positive control) inhibited the proliferation of all cancer cell lines tested. The IC50 values for aridanin varied from 3.18 µM (CCRF-CEM cells) to 9.56 µM (HepG2 cells). Aridanin had considerably lower IC50 values than that of doxorubicin against multidrug-resistant CEM/ADR5000 cells and melanoma cell lines (MaMel-80a, Mel-2a, MV3, and SKMel-505). Aridanin induced apoptosis in CCRF-CEM cells through increase of ROS levels and MMP breakdown, and to a lesser extent via caspases activation. Aridanin also induced ferroptotic and necroptotic cell death. CONCLUSION: The present study opens good perpectives for the use of this phytochemical as an anticancer drug to combat multi-facorial resistance to established chemotherapeutics.
