Perhexiline

We tested the sensitivity of PDAC cells to three different compounds targeting the Fatty Acid Oxidation (FAO) pathway: etomoxir, perhexiline, and trimetazidine (all provided by Sigma-Aldrich, Saint-Quentin Fallavier, France), and to the chemotherapeutic gemcitabine (Gemzar, Eli Lilly & Co). Cells were seeded in 96-well plates (5,000 cells per well) and 24 hours later, the medium was supplemented with increasing concentrations of the drugs in triplicates. For the combination treatments, we used perhexiline at 5 μM with increasing doses of gemcitabine. Viability was determined 72 hours later by the Crystal violet assay, which is independent from cell metabolism. For this, cells were fixed in glutaraldehyde (1%), washed twice with PBS, stained with Crystal violet (0.1%) for 10 min, and then washed three times with PBS. Crystals were solubilized in SDS (1%), and absorbance was measured at 600 nm using an Epoch-Biotek spectrophotometer.
We calculated the synergistic effect of the combination treatments as previously reported.²⁸ (link) To calculate the predicted values, the cell viability of gemcitabine-treated cells was multiplied by the cell viability of perhexiline-treated cells. A synergistic effect was considered when the observed value is lower than the predicted value.