Enhancement of Cytotoxicity of Hydrogen Peroxide by Hyperthermia in Chinese Hamster Ovary Cells: Role of Antioxidant Defenses

1999 ◽  
Vol 363 (2) ◽  
pp. 283-295 ◽  
Author(s):  
Stephanie Lord-Fontaine ◽  
Diana A. Averill
Keyword(s):  
Hydrogen Peroxide ◽  
Chinese Hamster Ovary ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Antioxidant Defenses ◽  
Ovary Cells

Aldehyde dehydrogenase and cytotoxicity of purified bovine serum amine oxidase and spermine in Chinese hamster ovary cells

1994 ◽  
Vol 72 (1-2) ◽  
pp. 36-42 ◽  
Author(s):  
Diana A. Averill-Bates ◽  
Enzo Agostinelli ◽  
Ewa Przybytkowski ◽  
Bruno Mondovi
Keyword(s):  
Hydrogen Peroxide ◽  
Aldehyde Dehydrogenase ◽  
Chinese Hamster Ovary ◽  
Bovine Serum ◽  
Amine Oxidase ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Oxidation Products ◽  
Ovary Cells

Bovine serum amine oxidase (EC 1.4.3.6) catalyses the oxidative deamination of polyamines giving rise to the corresponding aldehydes, ammonia, and hydrogen peroxide. It has been suggested that the dialdehyde produced during the oxidation of spermine subsequently undergoes spontaneous β-elimination to form acrolein. Oxidation of the aldehydes by aldehyde dehydrogenase (EC 1.2.1.5) thus eliminates these reactive species and prevents the formation of acrolein. This work studies the role of each of the oxidation products of spermine in cytotoxicity induced by purified bovine serum amine oxidase. The inhibition patterns of NAD-dependent aldehyde dehydrogenase and catalase against cytotoxicity of bovine serum amine oxidase were determined in Chinese hamster ovary cells at 37 °C. Cytotoxicity caused by exogenous hydrogen peroxide, added directly (> 10 μM) or generated by glucose oxidase (0.5 U/mL), was completely inhibited by catalase. Cytotoxicity caused by bovine serum amine oxidase (5.7 × 10−3 U/mL) and spermine (340 μM) was completely inhibited by catalase only during short incubation times after which time cytotoxicity occurred. This indicates that hydrogen peroxide was the only species contributing to cytotoxicity at this stage of the reaction. Aldehyde dehydrogenase alone caused partial inhibition of cytotoxicity, but only later in the reaction. Cytotoxicity was completely eliminated in the presence of both catalase and aldehyde dehydrogenase. Exogenous acrolein (> 50 μM) also caused cytotoxicity in Chinese hamster ovary cells. However, hydrogen peroxide was toxic to cells at lower concentrations and at shorter exposure times relative to aldehydes. These data show that both peroxide and aldehydes contribute to cytotoxicity of oxidation products of spermine. Aldehydes such as acrolein are responsible for cytotoxicity that cannot be accounted for by hydrogen peroxide.Key words: acrolein, hydrogen peroxide, catalase, polyamine.

Reduction of endogenous GRP78 levels improves secretion of a heterologous protein in CHO cells

1988 ◽  
Vol 8 (10) ◽  
pp. 4063-4070
Author(s):  
A J Dorner ◽  
M G Krane ◽  
R J Kaufman
Keyword(s):  
Endoplasmic Reticulum ◽  
Chinese Hamster Ovary ◽  
Heterologous Protein ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Glycosylation Site ◽  
Ovary Cells ◽  
Tissue Plasminogen ◽  
Stable Association

GRP78 is localized in the endoplasmic reticulum and associates with improperly folded or underglycosylated proteins. The role of GRP78 in secretion was studied in Chinese hamster ovary cells expressing a tissue plasminogen activator (tPA) variant which lacks potential N-linked glycosylation site sequences because of mutagenesis. The expression of variant tPA resulted in elevated levels of GRP78 and its stable association with tPA. The introduction of antisense GRP78 genes resulted in a two- to threefold reduction in GRP78 levels compared with those of the original cells. Cells with reduced levels of GRP78 secreted two- to threefold-higher levels of tPA activity. tPA expressed in these cells displayed reduced association with GRP78, and a greater proportion was processed to the mature form and secreted. These results demonstrate that reduction of GRP78 level can improve the secretion of an associated protein.

The role of O6-alkylguanine in cell killing and mutagenesis in Chinese hamster ovary cells

1991 ◽  
Vol 12 (1) ◽  
pp. 83-89 ◽  
Author(s):  
William C. Dunn ◽  
Keizo Tano ◽  
Gregory J. Horesovsky ◽  
R.Julian Preston ◽  
Sankar Mitra
Keyword(s):  
Chinese Hamster Ovary ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Cell Killing ◽  
Ovary Cells
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