A Jurkat T cell variant resistant to death receptor-induced apoptosis. Correlation with heat shock protein (Hsp) 27 and 70 levels

Ligation of Fas induces an apoptotic program in Jurkat cells (Jd), We descr ibe a Jurkat T cell variant (Jr) which shows total resistance to Fas-mediat ed apoptosis but which exhibits sensitivity to non-death-receptor pro-apopt otic stimuli such as staurosporine, Resistance to Fas-induced apoptosis in Jr cells is correlated with high expression of Hsps, A prior heat-shock inc reases Hsp27 and 70 expression and protects Jd and Jr cells from Fas- and s taurosporine-induced apoptosis. Staurosporine, but not the anti-l;as antibo dy CH11, abrogates constitutive Hsp70 expression at 37 degreesC and stauros porine also inhibit Hsp27 expression in Jd and Jr cells at 42 degreesC, The se data suggest that constitutive expression of Hsp27 inhibits Fas-mediated apoptosis, but only induced expression of Hsp70 can protect T cells from s taurosporine-induced apoptosis, Thus, Hsp27 could play a role in the regula tion of death receptor-mediated apoptosis, while Hsp70 could regulate mitoc hondrial-dependent cell death.