Specific inhibition of desmosterol synthesis by ML--236B in mouse LM cells grown in suspension in a lipid-free medium.
The suspended growth of LM cells in a lipid-free chemically defined medium was almost completely inhibited in the presence of 0.1 microgram/ml of ML-236B, a potent competitive inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, the rate limiting enzyme in cholesterol biosynthesis in mammalian cells. This inhibition was effectively counteracted by adding a small amount of either mevalonate or cholesterol (dispersed in delipidated calf serum) to culture medium. The synthesis of desmosterol, the end product of sterol biosynthesis in LM cells, from [14C]acetate in cultured cells was highly sensitive to ML-236B, being inhibited 35 and 60% at its concentrations of 0.1 and 1 ng/ml, respectively, while the incorporation of [3H]mevalonate into desmosterol was not affected by ML-236B at concentrations up to 0.1 microgram/ml. Synthesis of fatty acids, phospholipids, triglycerides and macromolecules like DNA, RNA and protein were not suppressed by 10 microgram/ml of ML-236B. Desmosterol content of LM cells was reduced by treatment with ML-236B. These results indicate that ML-236B inhibited cell growth via specific interference in the pathway of sterol biosynthesis, presumably on the step catalyzed by HMG-CoA reductase.
D000818:Animals; D002478:Cells, Cultured; D003864:Depression, Chemical; D003897:Desmosterol / Q000096:biosynthesis*; D005227:Fatty Acids / Q000096:biosynthesis; D006131:Growth Inhibitors; D008148:Lovastatin / Q000031:analogs & derivatives; D008798:Mevalonic Acid / Q000378:metabolism / Q000494:pharmacology; D051379:Mice; D009281:Naphthalenes / Q000494:pharmacology*; D009696:Nucleic Acids / Q000096:biosynthesis; D010743:Phospholipids / Q000096:biosynthesis; D014280:Triglycerides / Q000096:biosynthesis
D005227:Fatty Acids; D006131:Growth Inhibitors; D009281:Naphthalenes; D009696:Nucleic Acids; D010743:Phospholipids; D014280:Triglycerides; C012258:mevastatin; D003897:Desmosterol; D008148:Lovastatin; D008798:Mevalonic Acid