Retinoic acid와 dibutyryl cyclic AMP가 F9 embryonic carcinoma cell 분화 중 G1 Phase 관련 분자에 미치는 영향

Effect of Retinoic Acid and dibutyryl cyclic AMP on G1 Phase Associated Molecules during F9 Embryonic Carcinoma Cell Differentiation

Retinoic acid (RA) and dibutyryl cyclic AMP (dbcAMP) induce the differentiation of the multipotent embryonic carcinoma cell line, F9 cells, into parietal endoderm like cell. The F9 cells are highly proliferative doubling approximately 12 hours. S Phase is predominant, lasting 10 hours and G2/M phase occupies most of the remaining cycle (2 hours) and G1 phase is nearly non-existent. In this study, we showed the effect of RA and dbcAMP on the cell cycle associated molecules (especially around Gl phase) during F9 cell differentiation. Differentiation of F9 cells was induced by the combined addition of RA (10-7M) and dbcAMP (0.5mM), and cells were harvested daily up to 4 days. Flow cytometric analysis showed the prolongation of G1 phase around 30 hours after induction. Western blot analysis revealed that the amount of cyclin D1 and cdk2 were increased at day 4. However, histone H1 kinase activity of cdk2 was decreased. These data strongly suggest that RA and dbcAMP induce the growth arrest of F9 cells at G1 phase by decreasing the activity of cdk2, although they have increased the protein contents of cyclin Dl and cdk2. The reason for the discrepancy between the Hl kinase activity and protein contents are not clear yet.