Polyethylene glycol induces apoptosis in HT-29 cells: potential mechanism for chemoprevention of colon cancer

Recent experimental evidence suggests that polyethylene glycol (PEG) is a highly effective chemopreventive agent against colon cancer; however, the mechanism(s) remain largely unexplored, To further elucidate this issue, we evaluated the effect of PEG on two human colon cancer cell lines. PEG treatment resulted in a dose- and time-dependent reduction in cell number without alteration in markers of cell proliferation. However, there was a dramatic and specific, concentration-dependent induction of apoptosis, with 50 mM PEG rendering approximately half the cells apoptotic, This corresponded with a 17-fold induction in the expression of the pro-apoptotic protein, prostate apoptosis response-4, Our data suggest that induction of apoptosis may be responsible, at least in part, for the ability of PEG to prevent experimental colon cancer. (C) 2001 Published by Elsevier Science B.V. on behalf of the Federation of European Biochemical Societies.