scholarly journals Indomethacin inhibits cholera toxin-induced cyclic AMP accumulation in Chinese hamster ovary cells

1988 ◽  
Vol 49 (2) ◽  
pp. 187-192 ◽  
Author(s):  
Johnny W. Peterson ◽  
William D. Berg ◽  
Laura G. Ochoa
Keyword(s):  
Cyclic Amp ◽  
Cholera Toxin ◽  
Chinese Hamster Ovary ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Ovary Cells ◽  
Cyclic Amp Accumulation

scholarly journals Cholera toxin treatment stimulates tumorigenicity of Rous sarcoma virus-transformed cells.

1984 ◽  
Vol 4 (12) ◽  
pp. 2639-2642 ◽  
Author(s):  
M M Gottesman ◽  
C Roth ◽  
G Vlahakis ◽  
I Pastan
Keyword(s):  
Cyclic Amp ◽  
Cholera Toxin ◽  
Chinese Hamster Ovary ◽  
Rous Sarcoma Virus ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Tumor Formation ◽  
Ovary Cells ◽  
Rous Sarcoma ◽  
Sarcoma Virus

Chinese hamster ovary cells transformed by Rous sarcoma virus form tumors poorly in nude mice. Tumorigenicity was markedly stimulated by pretreatment of the cells with cholera toxin, which raises cyclic AMP levels and activates cyclic AMP-dependent protein kinase. Increased tumorigenicity was manifested by a severalfold increase in the rate of tumor formation, as well as earlier appearance and more rapid growth of tumors. In contrast, spontaneously transformed Chinese hamster ovary cells showed decreased tumorigenicity after cholera toxin treatment. The activation of tumorigenic potential in Rous sarcoma virus-transformed Chinese hamster ovary cells by cholera toxin correlated with increased phosphorylation of the viral oncogene product pp60src and stimulation of its tyrosine kinase activity.

Cholera toxin treatment stimulates tumorigenicity of Rous sarcoma virus-transformed cells

1984 ◽  
Vol 4 (12) ◽  
pp. 2639-2642
Author(s):  
M M Gottesman ◽  
C Roth ◽  
G Vlahakis ◽  
I Pastan
Keyword(s):  
Cyclic Amp ◽  
Cholera Toxin ◽  
Chinese Hamster Ovary ◽  
Rous Sarcoma Virus ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Tumor Formation ◽  
Ovary Cells ◽  
Rous Sarcoma ◽  
Sarcoma Virus

Chinese hamster ovary cells transformed by Rous sarcoma virus form tumors poorly in nude mice. Tumorigenicity was markedly stimulated by pretreatment of the cells with cholera toxin, which raises cyclic AMP levels and activates cyclic AMP-dependent protein kinase. Increased tumorigenicity was manifested by a severalfold increase in the rate of tumor formation, as well as earlier appearance and more rapid growth of tumors. In contrast, spontaneously transformed Chinese hamster ovary cells showed decreased tumorigenicity after cholera toxin treatment. The activation of tumorigenic potential in Rous sarcoma virus-transformed Chinese hamster ovary cells by cholera toxin correlated with increased phosphorylation of the viral oncogene product pp60src and stimulation of its tyrosine kinase activity.

Melanogenesis in murine B16 cells exposed to Aeromonas hydrophila cytotoxic enterotoxin

1986 ◽  
Vol 32 (10) ◽  
pp. 814-819 ◽  
Author(s):  
V. K. Bunning ◽  
R. G. Crawford ◽  
G. N. Stelma Jr. ◽  
L. O. Kaylor ◽  
C. H. Johnson
Keyword(s):  
Cholera Toxin ◽  
Chinese Hamster Ovary ◽  
Aeromonas Hydrophila ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Ovary Cell ◽  
Transferase Activity ◽  
End Points ◽  
Ovary Cells ◽  
Culture Filtrates

Specific markers (growth, melanogenesis) of B16 murine melanoma cells in culture were used as indicators of toxin production by Aeromonas hydrophila. Cytotonic enterotoxinlike activity (inhibited growth, raised tyrosinase activity, and melanin accumulation) occurred at cytotoxic end points of purified β-hemolysin and several culture filtrates. Antihemolysin rabbit serum inhibited this activity. A hemolysin-neutralized culture filtrate concentrate (10×) failed to elevate tyrosinase relative to untreated and cholera toxin treated controls. Similar dilution profiles using Chinese hamster ovary cells showed limited cell extension only at cytotoxic end points with antihemolysin inhibiting this activity. Cytotoxicity of Chinese hamster ovary cells and B16 cells was proportional to hemolytic activity, with B16 cells showing about 100-fold greater sensitivity on a per cell basis. Cell culture cytotoxicity attributed to β-hemolysin correlated with reactivity in rabbit ileal loop assays. The ADP-ribosyl transferase activity of concentrated (10×) A. hydrophila culture filtrates and fractions thereof was negative. Apparently sublethal doses of A. hydrophila β-hemolysin can nonspecifically stimulate cyclic adenosine monophosphate mediated events in melanoma and Chinese hamster ovary cell assays, producing lower activities than cholera toxin with shorter lag times.

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