Nexium

For viability assays, cells were plated onto 96-well plates and allowed to attach for 24 hours (SCC) or 48 hours (EAC). Then, phenol red free medium containing esomeprazole (Nexium®, AstraZeneca, Germany) at various concentrations was freshly prepared and added to the corresponding cells. After 72 hours, cell viability assays were performed as described below.
For adhesion and migration assays, cells were incubated in T75 flasks for 72 hours with esomeprazole at the approximate median lethal doses (LD50, as estimated from cell viability experiments). Adhesion and migration assays were then performed as described below.
For chemotherapy experiments, cells were treated for 72 hours with either esomeprazole alone at different concentrations (50 ?M: ¿sub-lethal¿, 86-100% cell survival; 250 ?M: ¿lethal¿, 20-30% cell survival; 350 ?M: ¿highly lethal¿, <10% cell survival), or with cisplatin or 5-fluorouracil at the LD50 concentrations, or with esomeprazole and chemotherapeutics together.
For experiments on the effect of PPI treatment on intra- and extracellular pH/proton concentrations or on miRNA expression, cells were incubated for 24/48/72 respectively 72 hours with esomeprazole at the approximate LD50 dosis (as estimated from cell viability experiments). Experiments were then performed as described below.

Norvir (100 mg ritonavir; Abbvie, North Chicago, IL, USA) and Nexium (40 mg esomeprazole; AstraZeneca, London, UK) tablets were ordered via the hospital pharmacy of the University Hospitals Leuven (UZ Leuven, Leuven, Belgium).