Cell cycle arrest and induction of apoptosis by beta galactoside binding protein (beta GBP) in human mammary cancer cells. A potential new approach to cancer control

Conflict between mitogenic pressure, as is the case in tumour cells and an imposed inability to proceed through the cell cycle may result in cell deat h. In the present study we examined the effect of beta galactoside binding protein (beta GBP), a negative growth factor which controls cell cycle tran sition from S phase into G(2), on three human mammary cell lines which diff er for oncogenic potential, oestrogen receptor expression and expression of the EGF receptor family. We found that in all cases beta GBP induced a cel l cycle block prior to the cells' entry into G(2) and that this was followe d by progressive apoptotic death. This evidence on epithelial cancer cells parallels previous data on tumour cells of mesenchymal origin and suggests that beta GBP has potential therapeutic implications in the treatment of ca ncers. (C) 1999 Published by Elsevier Science Ltd. All rights reserved.