Induction of apoptosis in p53-null HL-60 cells by inhibition of lanosterol 14-alpha demethylase.
To determine the role of cholesterol deprivation in cell proliferation and, eventually, in apoptosis, HL-60 promyelocytic cells were incubated in a cholesterol-depleted medium in the presence of SKF 104976, a specific inhibitor of lanosterol 14-alpha demethylase. As expected, SKF 104976 efficiently blocked the [14C]-acetate incorporation into cholesterol, whereas it induced the accumulation of both lanosterol and, especially, dihydrolanosterol. As a consequence, cell proliferation was greatly depressed at 24 h of treatment with the drug, and clear signs of apoptosis--annexin V binding, condensed and fragmented nuclei and DNA ladder--were observed thereafter. Provided that the HL-60 cell line does not express p53, it may be concluded that apoptosis induced by cholesterol deprivation is not dependent on this tumor suppressor protein. Supplementing the incubation medium with LDL-cholesterol or pure free cholesterol, fully prevented cell growth inhibition and apoptosis induction, whereas mevalonate was ineffective. These results indicate that cholesterol plays a specific role in cell proliferation, a function that is not shared by its precursors lanosterol and dihydrolanosterol.
Martínez-Botas
J
J
Servicio de Bioquímica-Investigación, Hospital Ramón y Cajal, Madrid, Spain.
Ferruelo
A J
AJ
Suárez
Y
Y
Gómez-Coronado
D
D
Lasunción
M A
MA
D017209:Apoptosis / Q000187:drug effects*; D002455:Cell Division; D002784:Cholesterol / Q000502:physiology; D065607:Cytochrome P-450 Enzyme Inhibitors; D005434:Flow Cytometry; D016158:Genes, p53 / Q000502:physiology*; D018922:HL-60 Cells; D006801:Humans; D007810:Lanosterol / Q000031:analogs & derivatives / Q000494:pharmacology; D008856:Microscopy, Fluorescence; D010088:Oxidoreductases / Q000037:antagonists & inhibitors*; D058886:Sterol 14-Demethylase; D013997:Time Factors
C548418:CYP51A1 protein, human; D065607:Cytochrome P-450 Enzyme Inhibitors; C071375:SK&F 104976; D007810:Lanosterol; D002784:Cholesterol; D010088:Oxidoreductases; D058886:Sterol 14-Demethylase