Rous sarcoma virus transformed cells are resistant to cyclic AMP

Area of Science:

• Cell biology
• Virology
• Molecular biology

Background:

• Spontaneous transformation is a common phenomenon in cell culture.
• Rous sarcoma virus (SR-RSV) is a retrovirus known to induce tumors.
• Cyclic AMP (cAMP) plays a crucial role in regulating cell growth and differentiation.

Purpose of the Study:

• To investigate the effects of SR-RSV transformation on Chinese hamster ovary (CHO) and rat (NRK) cells.
• To compare viral transformation with spontaneous transformation in terms of cellular responses.
• To determine if SR-RSV transformation affects cAMP-dependent protein kinase activity.

Main Methods:

• Transformation of CHO and NRK cells with SR-RSV.
• Assessing cellular response to 8-Br-cyclic AMP and cholera toxin.
• Analyzing cAMP-dependent protein kinase activity, including enzyme level, activation, and substrate phosphorylation.

Main Results:

• SR-RSV transformed CHO cells exhibited increased resistance to growth inhibition and cell shape changes induced by 8-Br-cyclic AMP and cholera toxin compared to spontaneously transformed cells.
• SR-RSV transformed NRK cells showed reduced sensitivity to growth inhibition by 8-Br-cyclic AMP.
• No significant differences in cAMP-dependent protein kinase activity were observed between SR-RSV transformed and control cells.

Conclusions:

• SR-RSV transformation induces distinct cellular alterations compared to spontaneous transformation in CHO and NRK cells.
• The observed differences in cellular response are not attributable to changes in cAMP-dependent protein kinase activity.
• Viral transformation by SR-RSV represents a unique mechanism of cellular modulation.