[Heat sensitivity of cultured choriocarcinoma cell line (BeWo)]

In order to elucidate the effect of hyperthermia, gestational choriocarcinoma cell line (BeWo) was studied with respect to cell growth and hormone (beta-HCG) production in various conditions of hyperthermia. BeWo was heated in the 39.0-43.0 degrees C temperature range on Day 4. The cell growth was reduced significantly at 43 degrees C for 1 hour. The same effect was observed at 39 degrees C for 120 hours. And this effect was more severe than that at 41 degrees C for 24 hours. BeWo was heated at 43 degrees C on Day 4, Day 5, and Day 6 during the logarithmic growth phase. Maximum suppression of the cell growth was observed on Day 4, and the effect was reduced with the length of time that heat application was delayed. MTX (10(-7)M) was added for 48 hours beginning on Day 4, and heat (43 degrees C for 1 hour) was applied at various points during or after MTX exposure. Heat showed an adjuvant effect with MTX when heat was applied between 24 hours after administration of MTX and 4 hours after removal of MTX. These findings strongly suggest that the heat sensitivity of BeWo is greatly related to the cell cycle. Elevated HCG production was not observed following heat alone, but observed following simultaneous heat and MTX administration. To elucidate the mechanism involved here, further studies will be needed.