Biomaterial Database

Sterol synthesis in variant Chinese hamster lung cells selected for resistance to 25-hydroxycholesterol. Cross-resistance to 7-ketocholesterol, 20alpha-hydroxycholesterol, and serum. 1979

H W Chen, and W K Cavenee, and A A Kandutsch

Two lines of Chinese hamster lung (Dede) cells which are resistant to the killing effect of 25-hydroxycholesterol, and which grow to confluence in its presence, have been isolated. One of the resistant lines exhibited a high to normal growth rate and normal levels of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase (mevalonate:NADP+ oxidoreductase (CoA-acylating), EC 1.1.1.34) activity and sterol synthesis in the presence of concentrations of 25-hydroxycholesterol that caused nearly complete suppression of these functions in wild type cells. The other variant line showed partial resistance to the inhibitory effects of the diol upon cell growth, sterol synthesis, and HMG-CoA reductase activity. The resistant phenotypes remained stable when the cells were maintained in the absence of the selecting agent. The Km (HMG-CoA), thermal stability, and susceptibility to inhibition by Mg2+ and ATP of HMG-CoA reductase were unaltered in both of the resistant lines. The two lines selected for growth in the presence of 25-hydroxycholesterol were also resistant to the inhibitory effects of 7-ketocholesterol, 20alpha-hydroxycholesterol, and serum upon HMG-CoA reductase and sterol synthesis, suggesting that suppression of cholesterol synthesis by these inhibitors involves a common step.

UI	MeSH Term	Description	Entries
D007653	Ketocholesterols	Cholesterol substituted in any position by a keto moiety. The 7-keto isomer inhibits cholesterol uptake in the coronary arteries and aorta by blocking 3-hydroxy-3-methylglutaryl-CoA reductase activity.	Oxocholesterols
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D010743	Phospholipids	Lipids containing one or more phosphate groups, particularly those derived from either glycerol (phosphoglycerides see GLYCEROPHOSPHOLIPIDS) or sphingosine (SPHINGOLIPIDS). They are polar lipids that are of great importance for the structure and function of cell membranes and are the most abundant of membrane lipids, although not stored in large amounts in the system.	Phosphatides,Phospholipid
D002460	Cell Line	Established cell cultures that have the potential to propagate indefinitely.	Cell Lines,Line, Cell,Lines, Cell
D002470	Cell Survival	The span of viability of a cell characterized by the capacity to perform certain functions such as metabolism, growth, reproduction, some form of responsiveness, and adaptability.	Cell Viability,Cell Viabilities,Survival, Cell,Viabilities, Cell,Viability, Cell
D002784	Cholesterol	The principal sterol of all higher animals, distributed in body tissues, especially the brain and spinal cord, and in animal fats and oils.	Epicholesterol
D003470	Culture Media	Any liquid or solid preparation made specifically for the growth, storage, or transport of microorganisms or other types of cells. The variety of media that exist allow for the culturing of specific microorganisms and cell types, such as differential media, selective media, test media, and defined media. Solid media consist of liquid media that have been solidified with an agent such as AGAR or GELATIN.	Media, Culture
D004351	Drug Resistance	Diminished or failed response of an organism, disease or tissue to the intended effectiveness of a chemical or drug. It should be differentiated from DRUG TOLERANCE which is the progressive diminution of the susceptibility of a human or animal to the effects of a drug, as a result of continued administration.	Resistance, Drug
D006888	Hydroxycholesterols	Cholesterol which is substituted by a hydroxy group in any position.
D006903	Hydroxymethylglutaryl CoA Reductases	Enzymes that catalyze the reversible reduction of alpha-carboxyl group of 3-hydroxy-3-methylglutaryl-coenzyme A to yield MEVALONIC ACID.	HMG CoA Reductases,3-Hydroxy-3-methylglutaryl CoA Reductase,HMG CoA Reductase,Hydroxymethylglutaryl CoA Reductase,3 Hydroxy 3 methylglutaryl CoA Reductase,CoA Reductase, 3-Hydroxy-3-methylglutaryl,Reductase, 3-Hydroxy-3-methylglutaryl CoA