[Influence of cell-cell interaction upon differentiation of murine embryonal carcinoma cells]

Embryonal carcinoma (EC) cells are the pluripotent stem cells of teratocarcinoma. The aggregates of P19, a mouse EC cell line, undergo differentiation and rapidly lose its colony-forming ability in culture with retinoic acid (RA) or DMSO. Loss of plating efficiency is used to assess the rate of drug-induced differentiation. When exposed respectively to DMSO or RA, the isolated EC cell mutants (D3 and RAC65) did not differentiate but the gap junctions could be formed. In RA-treated co-aggregates of RAC65 and O1A1, each cell line gave responses independent of the presence of the other cell line. However, in DMSO-treated co-aggregates of P19 and D3, D3 cells remained undifferentiated and P19 cell differentiation was much poorer than that in the absence of D3 cells. The results suggest that cell-cell interaction be present in the early stage of DMSO-induced differentiation and absent in the early stage of RA-induced differentiation.