Statin-dependent modulation of mitochondrial metabolism in cancer cells is independent of cholesterol content

Statins, widely used to treat hypercholesterolemia, inhibit the 3-hydroxy-3-methylglutaryl-coenzyme A reductase, the rate-limiting enzyme of de novo cholesterol (Chol) synthesis. Statins have been also reported to slow tumor progression. In cancer cells, ATP is generated both by glycolysis and oxidative phosphorylation. Mitochondrial membrane potential (ΔΨ), a readout of mitochondrial metabolism, is sustained by the oxidation of respiratory substrates in the Krebs cycle to generate NADH and flavin adenine dinucleotide, which are further oxidized by the respiratory chain. Here, we studied the short-term effects of statins (3–24 h) on mitochondrial metabolism on cancer cells. Lovastatin (LOV) and simvastatin (SIM) increased ΔΨ in HepG2 and Huh7 human hepatocarcinoma cells and HCC4006 human lung adenocarcinoma cells. Mitochondrial hyperpolarization after LOV and SIM was dose and time dependent. Maximal increase in ΔΨ occurred at 10 µM and 24 h for both statins. The structurally unrelated atorvastatin also hy...