CELLULAR-CHANGES IN HELA-CELLS AND CERVIX CELLS AFTER TREATMENT WITH CYCLIC-NUCLEOTIDES

Determination of tumor cell maturity and induction of cell differentia tion are significant issues in oncology. We studied here in vitro the effects of cyclic AMP and cyclic GMP on human cervix carcinoma cells ( HeLa cells), using normal human cervix cells as controls. Relative pla sma membrane fluidity (which corresponds with the adhesive power of th e cell, membrane permeability, and the ability to maintain the ionic m ilieu), cell cycle characteristics, and protein kinase C activity (a r egulator of the cell cycle) were determined. In the untreated HeLa cel ls, membrane fluidity and protein kinase C activity were increased ver sus the controls. Administration of dbcAMP decreased the membrane flui dity and the protein kinase C activity, prolonged the G0/G1 phase of t he cell cycle and shortened the S + G2 + M phase; with dbcGMP, the opp osite changes were recorded (all findings, p < 0.05). Findings from He La cells treated with dbcAMP approached those from the normal controls . Each of the parameter studied reflected the differentiation of the H eLa cells during dbcAMP treatment. They may be of potential use for th e determination of tumor cell maturity in clinical oncology.