Oleuropein (OLEU) is the most distinguished phenolic compound found in olive fruit and the leaves of Olea europaea L., with several pharmacological properties, including anti-cancer actions. Adriamycin (ADR) is an anthracycline widely used as a chemotherapeutic agent, although it presents significant side effects. The aim of the present study was to investigate the effect of oleuropein alone (20 μg/mL) and in co-treatment with ADR (50 nM), in MG-63 human osteosarcoma cells. Therefore, cellular and molecular techniques, such as MTT assay, flow cytometry, real-time Polymerase Chain Reaction (PCR), western blot and Elisa method, as well as Nuclear Magnetic Resonance (NMR) spectroscopy, were applied to unveil changes in the signal transduction pathways involved in osteosarcoma cells survival. The observed alterations in gene, protein and metabolite levels denote that OLEU not only inhibits MG-63 cells proliferation and potentiates ADR’s cytotoxicity, but also exerts its action, at least in part, through the induction of autophagy.
Sodium valproate, a histone deacetylase inhibitor, augments the expression of cell-surface NKG2D ligands, MICA/B, without increasing their soluble forms to enhance susceptibility of human osteosarcoma cells to NK cell-mediated cytotoxicity