Synergistic cytotoxic effect of quercetin and heat treatment in a lymphoid cell line (OZ) with low HSP70 expression.

ABSTRACT

Heat shock protein 70 (HSP70) protects cells from various injurious stimuli and is important in cell growth and differentiation. However, its expression in leukemia cells has not been analyzed systematically. We, therefore, investigated the expression of HSP70 in various types of leukemia cells and hematopoietic cell lines. Immunoblot analysis revealed that HSP72/73 were expressed at low levels in the acute lymphocytic leukemia cells and lymphoid cell lines examined. However, heat (43 C for 2 h) preferentially augmented HSP72/73 expression in lymphoid cells. This induction was partially blocked by the treatment with quercetin (10 microM for 24 h). Finally, heat shock following quercetin treatment synergistically induced apoptosis in a lymphoid cell line (OZ). These observations suggest the possibility of selective purging of lymphocytic leukemia cells by combination with quercetin and heat.