[Analysis of the mechanism of apoptosis induction by PSK].
ABSTRACT Previously, we reported that PSK induces apoptosis and growth inhibition in HL60 cells. In this study, we tried to clarify the mechanism of how PSK induces apoptosis. Because several reports suggested that apoptosis of HL60 cells is mediated by activation of p38MAPK, we examined whether p38MAPK is involved in PSK-induced apoptosis. First, we found that PSK induced p38MAPK phosphorylation, which is considered as its activation. Next, we demonstrated that SB203580, inhibitor of p38MAPK, inhibited PSK-induced apoptosis. These results suggest that p38MAPK plays an important role in PSK-induced apoptosis.