Potential mechanisms of resistance to TRAIL/Apo2L-induced apoptosis in human promyelocytic leukemia HL-60 cells during granulocytic differentiation.
Human promyelocytic leukemia HL-60 cells are well known to differentiate into granulocytes or monocytes in the presence of some agents such as DMSO or PMA, respectively. Differentiated HL-60 cells become resistant to some apoptotic stimuli including anticancer drugs or irradiation though undifferentiated cells significantly respond to these stimuli. TRAIL (TNF-related apoptosis-inducing ligand) which is also known as Apo2 ligand (Apo2L), a new member of TNF family, can induce apoptosis in some tumor cells but not in many normal cells. We show here that apoptosis is well induced in HL-60 cells by TRAIL, but susceptibility to TRAIL is reduced during granulocytic differentiation by DMSO. We also suggest some possible mechanisms by which granulocytic differentiated cells become resistant to TRAIL-induced apoptosis. First, in granulocytic differentiated cells, expression of antagonistic decoy receptors for TRAIL (TRAIL-R3/TRID/DcR1/LIT and TRAIL-R4/TRUNDD/DcR2) were enhanced. In addition, expression of Toso, a cell surface apoptosis regulator, seemed to block activation of caspase-8 by TRAIL via enhanced expression of FLIPL in granulocytic differentiated cells. These findings suggest that differentiated cells are resistant using plural mechanisms against various apoptosis-inducing stimuli rather than undifferentiated cells.
Department of Urology, Yamanashi Medical University, 1110 Shimokato, Tamaho-cho, Yamanashi 409-3898, Japan.
K
K
Shiiki
H
H
Yoshikawa
H
H
Kinoshita
M
M
Takeda
A
A
Ueno
Y
Y
Nakajima
K
K
Tasaka
D017209:Apoptosis / Q000276:immunology*; D051017:Apoptosis Regulatory Proteins; D053446:CASP8 and FADD-Like Apoptosis Regulating Protein; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D053148:Caspase 3; D053181:Caspase 8; D053453:Caspase 9; D020169:Caspases / Q000378:metabolism; D002454:Cell Differentiation / Q000276:immunology; D058851:GPI-Linked Proteins; D015870:Gene Expression / Q000502:physiology; D006098:Granulocytes / Q000166:cytology* / Q000201:enzymology; D018922:HL-60 Cells / Q000166:cytology* / Q000201:enzymology; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D018124:Receptors, Tumor Necrosis Factor / Q000235:genetics / Q000378:metabolism; D053320:Receptors, Tumor Necrosis Factor, Member 10c; D053221:TNF-Related Apoptosis-Inducing Ligand; D053319:Tumor Necrosis Factor Decoy Receptors; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000378:metabolism*
D051017:Apoptosis Regulatory Proteins; D053446:CASP8 and FADD-Like Apoptosis Regulating Protein; C506386:CFLAR protein, human; D002352:Carrier Proteins; C112037:FCMR protein, human; D058851:GPI-Linked Proteins; D047908:Intracellular Signaling Peptides and Proteins; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D018124:Receptors, Tumor Necrosis Factor; D053320:Receptors, Tumor Necrosis Factor, Member 10c; D053221:TNF-Related Apoptosis-Inducing Ligand; C108661:TNFRSF10C protein, human; C505653:TNFSF10 protein, human; D053319:Tumor Necrosis Factor Decoy Receptors; D014409:Tumor Necrosis Factor-alpha; C505407:CASP3 protein, human; C505530:CASP8 protein, human; C506433:CASP9 protein, human; D053148:Caspase 3; D053181:Caspase 8; D053453:Caspase 9; D020169:Caspases