Statin-induced apoptosis linked with membrane farnesylated Ras small G protein depletion, rather than geranylated Rho protein.
Rhabdomyolysis is a severe adverse effect of 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors (statins). This myopathy is strongly enhanced by the combination with statins and fibrates, another hypolipidaemic agent. We have evaluated the initial step of statin-induced apoptosis by the detection of membrane flip-flop using flow cytometric analysis. L6 rat myoblasts were treated with various statins (atorvastatin (3 microM), cerivastatin (3 microM), fluvastatin (3 microM), pravastatin (3 mM), or simvastatin (3 microM)) for 2, 4 or 6 h followed by reacting with FITC-conjugated annexin V for the detection of initial apoptosis signal (flip-flop). Various statin-treated myoblasts were significantly stained with FITC-annexin V at 6 h, whereas they were not detected at 2 h. Moreover, immunoblot analysis indicated that when the cells were treated with cerivastatin (3 microM), membrane-associated Ras protein was activated and detached until 6 h, resulting in cell death through the consequent activation of caspase-8. On the other hand, since cytosolic Ras activation did not activate, there is still an unknown mechanism in statin-related Ras depletion. In conclusion, statin-induced apoptosis in muscular tissue was directly initiated by the farnesyl-anchored Ras protein depletion from cell membrane with subsequent apoptosis.
Matzno
Sumio
S
School of Pharmaceutical Sciences, Mukogawa Women's University, 11-68, Kyuban-cho, Koshien, Nishinomiya, Hyogo 663-8179, Japan. smatzno@mwu.mukogawa-u.ac.jp
Yasuda
Shinya
S
Juman
Sachiko
S
Yamamoto
Yukiko
Y
Nagareya-Ishida
Noriko
N
Tazuya-Murayama
Keiko
K
Nakabayashi
Toshikatsu
T
Matsuyama
Kenji
K
D000818:Animals; D017209:Apoptosis; D000069059:Atorvastatin; D053181:Caspase 8 / Q000378:metabolism; D002460:Cell Line; D005229:Fatty Acids, Monounsaturated / Q000494:pharmacology; D005434:Flow Cytometry; D000077340:Fluvastatin; D006538:Heptanoic Acids / Q000494:pharmacology; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D007211:Indoles / Q000494:pharmacology; D008563:Membrane Lipids / Q000378:metabolism; D008856:Microscopy, Fluorescence; D032448:Myoblasts, Skeletal / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D017368:Protein Prenylation; D011725:Pyridines / Q000494:pharmacology; D011758:Pyrroles / Q000494:pharmacology; D051381:Rats; D015398:Signal Transduction / Q000187:drug effects; D018631:ras Proteins / Q000378:metabolism*; D020741:rho GTP-Binding Proteins / Q000378:metabolism
D005229:Fatty Acids, Monounsaturated; D006538:Heptanoic Acids; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D007211:Indoles; D008563:Membrane Lipids; D011725:Pyridines; D011758:Pyrroles; D000077340:Fluvastatin; D000069059:Atorvastatin; C086276:cerivastatin; C505528:Casp8 protein, rat; D053181:Caspase 8; D018631:ras Proteins; D020741:rho GTP-Binding Proteins