Inhibition of AMPK-dependent autophagy enhances in vitro antiglioma effect of simvastatin.

摘要: The role of autophagy, a process in which the cell self-digests its own components, was investigated glioma death induced by hydroxymethylglutaryl-coenzyme A (HMG-CoA) reductase-inhibiting drug simvastatin. Induction autophagy and activation autophagy-regulating signalling pathways were analyzed immunoblotting. Flow cytometry/fluorescent microscopy used to assess autophagy-associated intracellular acidification apoptotic markers (phosphatidylserine exposure, DNA fragmentation caspase activation). Cell viability determined crystal violet, MTT or LDH release assay. Simvastatin treatment U251 C6 lines caused appearance autophagolysosome-like intracytoplasmic acidic vesicles. induction cells confirmed upregulation autophagosome-associated LC3-II pro-autophagic beclin-1, as well downregulation selective autophagic target p62. AMP-activated protein kinase (AMPK) Raptor, while simultaneously downregulating Akt. Mammalian rapamycin (mTOR), major AMPK/Akt downstream negative regulator, substrate p70 S6 1 also inhibited Mevalonate, product HMG-CoA reductase enzymatic activity, AMPK siRNA pharmacological inactivation with compound C suppressed, inhibitors Akt (10-DEBC hydrochloride) mTOR (rapamycin) mimicked Inhibition bafilomycin A1, 3-methyladenine LC3β shRNA, inhibition siRNA, markedly increased simvastatin-treated cells. These data suggest that AMPK-dependent response might sensitize statin-induced death.