Effects of Dibutyryl Cyclic Adenosine Phosphate Plus Theophylline on Murine Sarcoma Virus Transformed Non-Producer Cells

Treatment of Kirsten sarcoma virus-transformed non-producer cells. (Ki-3T3) with dibutyryl cyclic adenosine phosphate and theophylline (dbcAMP + Th) resulted in marked changes in morphology, reduction in growth rate, and increased adhesiveness, suggesting a reversal towards the non-transformed BALB/3T3 (B-3T3) parent cell line. The morphologic changes were reversible by removal of the dbcAMP + Th. However, treatment of Ki-3T3 cells had little or no effect on the replication of leukemia virus, the presence and rescuability of the sarcoma genome, and the expression of virus-directed cell surface antigens. Sarcoma virus-transformed cells, including Ki-3T3 cells, characteristically have lowered K_m values for glucose transport. The treatment did not affect the K_m value, indicating that at least one important biochemical marker of the virus transformed state is unaffected by dbcAMP + Th treatment. Treated Ki-3T3 and B-3T3 cells had markedly increased V_max values for glucose transport.