Fas-mediated apoptosis and expression of related genes in human malignant hematopoietic cells.
Fas transduces apoptotic signals upon cross-linking with the Fas ligand (FasL), which is experimentally replaced by agonistic anti-Fas monoclonal antibodies (mAb). Of eight human malignant hematopoietic cell lines (HL-60, KG-1, THP-1, K562, U937, Jurkat, IM-9, RPMI-8226) examined by flow cytometric analysis, all, except K562, were found to be positive for surface Fas antigen. However, despite surface Fas expression, the agonistic anti-Fas mAb (7C11) induced apoptosis in only three of seven Fas-expressing cell lines (KG-1, Jurkat and IM-9). This Fas-resistance did not correlated with high levels of mRNA either for DcR3, a decoy receptor for FasL, or for FAP-1, a Fas-associated phosphatase that can block the apoptotic function of Fas. Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis did not show consistent differences in the expression of Bcl-2 and Bax between Fas-sensitive and Fas-resistant cell lines examined. These findings indicated that the presence or absence of mRNA expression of DcR3, FAP-1, Bcl-2 and Bax did not always correlate with relative sensitivity to Fas-mediated apoptosis. Treatment of cells with cycloheximide converted the phenotype of resistant cell lines from Fas-resistant to Fas-sensitive, and enhanced the sensitivity of Fas-sensitive cell lines. These results suggest that the Fas-resistance is dependent on the presence of labile proteins that determine resistance to Fas-mediated apoptosis and the apoptotic machinery is already in place in Fas-resistant cell lines.
Kim
K M
KM
Department of Biochemistry and Medical Research Center, College of Medicine, Ewha Womans University, Seoul, Korea.
Lee
K
K
Hong
Y S
YS
Park
H Y
HY
D017209:Apoptosis / Q000187:drug effects / Q000235:genetics*; D002352:Carrier Proteins / Q000096:biosynthesis / Q000235:genetics; D003513:Cycloheximide / Q000494:pharmacology; D053222:Fas Ligand Protein; D015972:Gene Expression Regulation, Neoplastic; D019337:Hematologic Neoplasms / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D008562:Membrane Glycoproteins / Q000378:metabolism*; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D054595:Protein Tyrosine Phosphatase, Non-Receptor Type 13; D017027:Protein Tyrosine Phosphatases / Q000096:biosynthesis / Q000235:genetics; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis / Q000235:genetics; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis / Q000235:genetics; D011956:Receptors, Cell Surface / Q000096:biosynthesis / Q000235:genetics; D018124:Receptors, Tumor Necrosis Factor; D053323:Receptors, Tumor Necrosis Factor, Member 6b; D015398:Signal Transduction; D014407:Tumor Cells, Cultured; D051028:bcl-2-Associated X Protein; D019014:fas Receptor / Q000378:metabolism*
C494826:BAX protein, human; D002352:Carrier Proteins; C505661:FASLG protein, human; D053222:Fas Ligand Protein; D008562:Membrane Glycoproteins; D011500:Protein Synthesis Inhibitors; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D011956:Receptors, Cell Surface; D018124:Receptors, Tumor Necrosis Factor; D053323:Receptors, Tumor Necrosis Factor, Member 6b; C505911:TNFRSF6B protein, human; D051028:bcl-2-Associated X Protein; D019014:fas Receptor; D003513:Cycloheximide; C516742:PTPN13 protein, human; D054595:Protein Tyrosine Phosphatase, Non-Receptor Type 13; D017027:Protein Tyrosine Phosphatases