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 necrosis factor receptor family that serves an important role in the induction 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) is limited.


METHODS
We analyzed both CD95-related apoptotic signaling and its effects on the expression of several factors involved in the regulation of apoptotic mechanisms including: caspase-3, caspase-8, bcl-2, bcl-x, and Bax in HD cell 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 correlation between CD95 sensitivity and constitutive expression levels of caspase-8, bcl-2, bcl-x, and Bax. Caspase-3 transcript was demonstrated by reverse transcriptase polymerase chain reaction (RT-PCR) in all cell lines but protein was at low to nearly undetectable levels in KM-H2 cells. Transfection of KM-H2 cells with pro-caspase-3 resulted in a markedly enhanced apoptotic 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-dependent apoptotic stimuli, including the death-inducing ligand, TRAIL, and the chemotherapeutic agent, Ara-C.


CONCLUSIONS
These data demonstrate that caspase-3 expression plays an important role in CD95-mediated apoptosis in HD cell lines. Furthermore, lack of or decreased expression of caspase-3 in HD cells impairs their apoptotic response not only to CD95 but also to other caspase-3-dependent apoptotic stimuli.
Wrone-Smith
T
T
Department of Pathology, Loyola University Medical Center, Maywood, Ill 60153, USA.
Izban
K F
KF
Ergin
M
M
Cosar
E F
EF
Hsi
E D
ED
Alkan
S
S
D000911:Antibodies, Monoclonal / Q000276:immunology / Q000494:pharmacology; D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology*; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D051017:Apoptosis Regulatory Proteins; D053148:Caspase 3; D053181:Caspase 8; D053453:Caspase 9; D020169:Caspases / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D003561:Cytarabine / Q000494:pharmacology*; D006689:Hodgkin Disease / Q000201:enzymology* / Q000473:pathology; D006801:Humans; D019169:Jurkat Cells; D008562:Membrane Glycoproteins / Q000494:pharmacology*; D009363:Neoplasm Proteins / Q000172:deficiency / Q000502:physiology*; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis; D012333:RNA, Messenger / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D053221:TNF-Related Apoptosis-Inducing Ligand; D014162:Transfection; D014407:Tumor Cells, Cultured / Q000187:drug effects; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D014750:Vincristine / Q000494:pharmacology; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein; D019014:fas Receptor / Q000276:immunology / Q000502:physiology*
D000911:Antibodies, Monoclonal; D000964:Antimetabolites, Antineoplastic; D000972:Antineoplastic Agents, Phytogenic; D051017:Apoptosis Regulatory Proteins; C494826:BAX protein, human; C494811:BCL2L1 protein, human; D008562:Membrane Glycoproteins; D009363:Neoplasm Proteins; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D053221:TNF-Related Apoptosis-Inducing Ligand; C505653:TNFSF10 protein, human; D014409:Tumor Necrosis Factor-alpha; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein; D019014:fas Receptor; D003561:Cytarabine; D014750:Vincristine; C505407:CASP3 protein, human; C505530:CASP8 protein, human; C506433:CASP9 protein, human; D053148:Caspase 3; D053181:Caspase 8; D053453:Caspase 9; D020169:Caspases