TRANSFORMED-CELLS TRIGGER INDUCTION OF THEIR OWN APOPTOSIS IN COCULTURE WITH NORMAL-CELLS

In vitro, transforming growth factor type betal triggers normal cells to induce apoptosis in transformed cells. We show that in the absence of exogenous transforming growth factor type betal, induction of apopt osis of transformed cells in coculture with normal cells is dependent on the number of transformed cells per assay and is abrogated by antib odies against TGF-beta 1. Therefore, transforming growth factor type b etal produced by transformed cells seems to be responsible for trigger ing a mechanism that leads to the induction of their apoptosis. This m echanism may be crucial for the control of carcinogenesis in vivo.