[CAS NO. 75330-75-5]  Lovastatin (MK-803)

Lovastatin inhibits LPS- and cytokine-mediated production of NO and expression of iNOS in rat primary astrocytes. Lovastatin inhibits LPS-induced expression of TNF-alpha, IL-1beta, and IL-6 in rat primary astrocytes, microglia, and macrophages. Lovastatin results in over 95% inhibition of DNA synthesis as measured by incorporation of [3H]thymidine into DNA. Lovastatin synchronizes cells in the G1 and not in the G0 phase of the cell cycle. Lovastatin has a similar growth-inhibitory activity against ras-dependent as well as ras-independent cell lines. Lovastatin produces a profound reduction of apolipoprotein-B-containing lipoproteins, especially LDL cholesterol and, to a lesser extent, plasma triglyc- erides, and a small increase in HDL cholesterol. Lovastatin arrests cells by inhibiting the proteasome, which results in the accumulation of p21 and p27, leading to G1 arrest. Lovastatin is an inhibitor of hydroxymethyl glutaryl (HMG)-CoA reductase, the rate-limiting enzyme in cholesterol synthesis. Lovastatin can be used to arrest cultured cells in the G1 phase of the cell cycle, resulting in the stabilization of the cyclin-dependent kinase inhibitors (CKIs) p21 and p27. Lovastatin (2-10 mM) arrests cells in G1 and also prolonged--or arrested a minor fraction of cells in--the G2 phase of the cell cycle in human bladder carcinoma T24 cell line expressing activated p21ras. Lovastatin (50 mM) is cytotoxic in human bladder carcinoma T24 cell line expressing activated p21ras.