THE INTERACTION BETWEEN CYTOTROPHOBLASTS AND THEIR DERIVED TUMOR-CELLS

Previous experiments demonstrated that human cytotrophoblasts and cell s of the choriocarcinoma cell line JAr interact in vitro. As a result of this interaction there is an increased synthesis of CG and hPL, pro bably as a result of the increased CG and hPL synthesis by the cytotro phoblasts. In the present investigation we studied this interaction in greater detail and found that both cytotrophoblasts and JAr cells und ergo changes in their biological properties as a result of this intera ction. JAr cells and cytotrophoblasts cocultured for 72 hr were fracti onated according to their size by centrifugal elutriation. The number of cells in the fraction which contain the largest cells was very sign ificantly increased as a result of the coculture. This increase was du e to an increase in the number of cells of both cell types. This fract ion was the most active one in the synthesis of CG and hPL. The synthe sis of DNA by the JAr nuclei in this fraction of the cocultured cells was almost completely inhibited but in the parallel fraction of the JA r cells cultivated alone the level of DNA synthesis was equal to that of all other JAr cell fractions. Heterokaryons are formed in the cocul ture. In these heterokaryons a factor which inhibits DNA synthesis in the cytotrophoblasts may inhibit DNA synthesis in JAr nuclei and at le ast be partly responsible for the inhibition of DNA synthesis observed . (C) 1995 Academic Press, Inc.