[Cyclic AMP content, protein kinase activity, and DNA structure in resting and proliferating peripheral blood lymphocytes and in human T-lymphoma cells].

Alterations of DNA structure, of cAMP content, of cAMP-dependent histokinases (HK) activity and cAMP-independent casein kinases (CK) activity were studied during transformation of resting cells to proliferation. These patterns were studied in human lymphocytes from peripheral blood immediately after their isolation and after cultivation within 3 days in presence of concanavalin A (ConA) or without the mitogen as well as in cultivated cells of human T-lymphoma Jurkat. Increase in content of alkaline labile sites in DNA, in activity of CK as well as distinct increase in content of cAMP were detected within the first 18 hrs of lymphocytes cultivation both in presence of ConA or without it. Early steps of cell transformation from G0 phase to G1 may be related to these alterations observed. Only slight increase in content of the alkaline labile sites in DNA and decrease in cAMP content were found in both these cell cultures. Activity of CK in the lymphocytes culture not containing ConA was decreased down to initial level, while in presence of the mitogen the enzymatic activity was increased and within 3 days it reached the level of CK activity in Jurkat cells. The rate of CK relative activity, calculated as CK/cAMP or CK/HK/cAMP ratios for each cell preparation, correlated with DNA biosynthesis rate measured by 3H-thymidine incorporation. The data obtained suggest that these patterns, used in differential diagnosis of human large intestine and gastric tumors, demonstrated also the intensity of tissue proliferation.