Mevastatin, an inhibitor of HMG-CoA reductase, induces apoptosis, differentiation and Rap1 expression in HL-60 cells.
It has been reported that inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase suppress cell proliferation and induce apoptosis. One inhibitor which induces apoptosis is mevastatin. However, the molecular mechanism of apoptosis induction is not well understood so the effects of mevastatin on various functions of HL-60 cells were investigated. We confirmed that mevastatin activated caspase-3 by release of cytochrome c (Cyt. c) from mitochondria through a membrane permeability transition mechanism and also induced typical fragmentation and ladder formation of DNA in HL-60 cells. These effects were inhibited by mevalonate, a metabolic intermediate of cholesterol biosynthesis. Mevalonate and geranylgeraniol (GGOH) inhibited DNA fragmentation whereas farnesol (FOH) did not. Mevastatin also induced cell differentiation to monocytic cells via a mevalonate inhibitable mechanism. Furthermore, mevastatin decreased the amount of an isoprenylated membrane bound Rap1 small GTPase concomitant with an increase in cytosolic Rap1 which occurred before apoptosis and differentiation. On the contrary, both mevastatin and geranylgeranylacetone (GGA), which competes with geranylgeranyl pyrophosphate, induced membrane depolarization of isolated mitochondria without swelling and Cyt. c release. These results suggest that mevastatin-induced apoptosis of HL-60 cells might be caused indirectly by activation of the caspase cascade through the modulation of mitochondrial functions and that some relationship between a certain small GTPase molecule, such as Rap1, and mevastatin-induced apoptosis may exist.
Kanno
Tomoko
T
Institute of Medical Science, Kurashiki Medical Center, Japan.
Kobuchi
Hirotsugu
H
Kajitani
Noriko
N
Utsumi
Toshihiko
T
Yano
Hiromi
H
Horton
Alan A
AA
Yasuda
Tatsuji
T
Utsumi
Kozo
K
D017209:Apoptosis / Q000187:drug effects*; D020170:Caspase 1 / Q000378:metabolism; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects*; D003574:Cytochrome c Group / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation; D018922:HL-60 Cells / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000008:administration & dosage; D008148:Lovastatin / Q000008:administration & dosage* / Q000031:analogs & derivatives*; D008564:Membrane Potentials / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects* / Q000502:physiology; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D020827:rap1 GTP-Binding Proteins / Q000096:biosynthesis*
D003574:Cytochrome c Group; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; C012258:mevastatin; D008148:Lovastatin; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases; D020170:Caspase 1; D020827:rap1 GTP-Binding Proteins