Transfection of caspase-3 in the caspase-3-deficient Hodgkin's disease cell line, KMH2, results in enhanced sensitivity to CD95-, TRAIL-, and ARA-C-induced apoptosis

Background. CD95(Fas/apo-1) is a cell surface protein member of the tumor n ecrosis factor receptor family that serves an important role in the inducti on of apoptosis in several cell types, Although expression of CD95 has been detected on Hodgkin/Reed Sternberg (HRS) cells in situ, our understanding of the biological significance of this molecule in Hodgkin's disease (HD) i s limited, Design. We analyzed both CD95-related apoptotic signaling and its effects o n the expression of several factors involved in the regulation of apoptotic mechanisms including: caspase-3, caspase-8, bcl-2, bcl-x, and Pax in HD ce ll lines (L-428, L-540, HDLM-2, HS-445, and KM-H2). Results. HD cell lines showed similar expression levels of CD95 and all but KM-H2 demonstrated variable increases in apoptosis after CD95 stimulation by the agonistic monoclonal antibody, CH11, There was no significant correl ation between CD95 sensitivity and constitutive expression levels of caspas e-8, bcl-2, bcl-x, and Pax, Caspase-3 transcript was demonstrated by revers e transcriptase polymerase chain reaction (RT-PCR) in all cell lines but pr otein was at low to nearly undetectable Levels in KM-H2 cells, Transfection of KR I-HZ cells with pro-caspase-3 resulted in a markedly enhanced apopto tic response to CD95 stimulation that was blocked by pretreatment with the caspase-3 inhibitor, DEVD-FMK, In addition, pro-caspase-3-transfected KM-H2 cells showed significantly increased sensitivity to other caspase-3-depend ent apoptotic stimuli, including the death-inducing ligand, TRAIL, and the chemotherapeutic agent, Ara-C, Conclusion. These data demonstrate that caspase-3 expression plays an impor tant role in CD95-mediated apoptosis in HD cell lines, Furthermore, lark of or decreased expression of caspase-3 in HD cells impairs their apoptotic r esponse not only to CD95 but also to other caspase-3-dependent apoptotic st imuli, (C) 2001 International Society for Experimental Hematology, Publishe d by Elsevier Science Inc.