TNF-related apoptosis-inducing ligand (TRAIL) is a newly identified member of the tumor necrosis factor (TNF) family. TRAIL induces apoptosis by activating caspase cascades, stimulating a loss of mitochondrial membrane potential (Delta Psim) and cytochrome C release in the FADD/caspase-8 dependent pathway. However, TRAIL can also trigger transcriptional activations of the pro-oncogene of c-fos, JNK, and NF-kappaB by other signaling pathways downstream of FADD/caspase-8. MAPK/ERK activation has a dominant protecting effect over apoptotic signaling from the death receptors. The functional expression of TRAIL by leukemic cells may be involved in tumor cells evasion of immunosurveillance. Somatic mutations of TRAIL-R1 and TRAIL-R2 genes may play a role in the pathogenesis of some tumors. TRAIL can induce apoptosis on various continuous transformed cell lines and primary tumor cells, including several of hematopoietic origin, displaying minimal toxic effects on normal tissues. Because of the abilities of induction of both cytotoxic (apoptosis) and cytostatic (cell cycle perturbation) effects on the leukemic cells, TRAIL is currently considered as a potential(co) therapeutic drug against tumors.
Animals ; Apoptosis Regulatory Proteins ; Hematologic Neoplasms ; etiology ; therapy ; Humans ; Membrane Glycoproteins ; physiology ; Mutation ; Receptors, TNF-Related Apoptosis-Inducing Ligand ; Receptors, Tumor Necrosis Factor ; genetics ; physiology ; Signal Transduction ; TNF-Related Apoptosis-Inducing Ligand ; Tumor Necrosis Factor-alpha ; physiology

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a member of the TNF super family found in recent years, which widely exists in the body tissues and participates in the immune regulation, immune stability, and immune surveillance of the human body. The TRAIL receptor is expressed in the surface of a variety of cells. Recent studies show that TRAIL induces the apoptosis of tumor cells and has no significant toxic effect on normal cells. Its anti-tumor activity and safety have been widely recognized. The development of prostate cancer is regulated by the mechanisms of cell apoptosis. TRAIL can induce the apoptosis of prostate cancer cells, and therefore has a great application value in the treatment of prostate cancer.
Antineoplastic Agents ; therapeutic use ; Apoptosis ; Apoptosis Regulatory Proteins ; Humans ; Male ; Membrane Glycoproteins ; Prostatic Neoplasms ; drug therapy ; pathology ; Receptors, TNF-Related Apoptosis-Inducing Ligand ; physiology ; therapeutic use ; TNF-Related Apoptosis-Inducing Ligand ; Tumor Necrosis Factor-alpha

OBJECTIVETumor necrosis factor related apoptosis inducing ligand (TRAIL) induces cell death in a variety of tumors but not in normal cells. TRAILdouble ended arrow-resistance of most neuroblastoma (NB) cell lines is related to the loss of caspase-8 expression and the expression and distribution of membrane TRAIL-receptors. This study investigated the role of caspase-8 and DR5 in TRAIL-induced apoptosis of NB cell line SKNDZ.

METHODSThe expression of caspase-8 mRNA was detected by RT-PCR. The expression of DR5 protein was detected by Western Blot analysis. The effects of TRAIL, IFNgamma +TRAIL, chemotherapeutic agent (adriamycin or etoposide) + TRAIL, and chemotherapeutic agent +TRAIL+ IFNgamma on the growth and apoptosis of SKNDZ cells were detected by MTT assay and flow cytometry.

RESULTScaspase-8 was not expressed in SKNDZ cells but IFNgamma treatment resulted in an increase of caspase-8 expression. Expression of DR5 protein was not detected in SKNDZ cells but an increased DR5 protein expression was found after treatment with adriamycin or etoposide. The SKNDZ cells expressing caspase-8 were not sensitive to TRAIL but those SKNDZ cells expressing both caspase-8 and DR5 were sensitive. The early apoptosis rates of the adriamycin /etoposide + IFNgamma+TRAIL groups [(17.9 +/- 3.6)%, (14.8 +/- 3.3)%] were higher than that of the IFNgamma+TRAIL group [(3.9 +/- 1.2)% ](F=26.233, P < 0.01).

CONCLUSIONSSKNDZ cells expressing both caspase-8 and DR5 restored the TRAIL sensitivity. Caspase-8 and DR5 play a key role in TRAIL-induced apoptosis of NB cells.

Apoptosis ; drug effects ; Apoptosis Regulatory Proteins ; pharmacology ; Blotting, Western ; Caspase 8 ; Caspases ; physiology ; Humans ; Interferon-gamma ; pharmacology ; Membrane Glycoproteins ; pharmacology ; Neuroblastoma ; pathology ; Receptors, TNF-Related Apoptosis-Inducing Ligand ; Receptors, Tumor Necrosis Factor ; physiology ; TNF-Related Apoptosis-Inducing Ligand ; Tumor Cells, Cultured ; Tumor Necrosis Factor-alpha ; pharmacology ; Tumor Suppressor Protein p53 ; physiology

Death receptors induce apoptosis by intracellular signaling transmission and relate to body growth, development, disease and death. This paper reviews the structural character of death receptors, and the mechanisms by which apoptosis is induced. The biology and pathobiology of these death receptors in liver are discussed as well.
Apoptosis ; physiology ; GPI-Linked Proteins ; Humans ; Liver ; pathology ; physiology ; Receptors, TNF-Related Apoptosis-Inducing Ligand ; Receptors, Tumor Necrosis Factor ; physiology ; Receptors, Tumor Necrosis Factor, Member 10c ; Tumor Necrosis Factor Decoy Receptors ; fas Receptor ; physiology

OBJECTIVETo explore the molecular mechanism via which the chemotherapeutic drug hydroxyurea (HU) enhances K562 cell apoptosis induced by tumor necrosis factor-related apoptosis-inducing ligand (TRAIL).

METHODSChronic myelogenous leukemia-derived K562 and SVT-35 cells were treated with recombinant soluble TRAIL (rsTRAIL) alone or combined with HU for a time course, and the cell viability was determined by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-4-sulfophenyl-2H-tetrazolium-phenazine methosulphate assay. Western blot was performed to analyze the activation of apoptosis-related protein kinases and the expression of apoptosis inhibitor molecules.

RESULTSThe survival rates of SVT-35 and K562 cells treated with 1 μg/ml rsTRAIL for 24 hours were 32% and 93%, respectively. HU significantly increased the sensitivity of K562 cells to rsTRAIL cytotoxicity. Combination of rsTRAIL and HU resulted in the phosphorylation of rat sarcoma (RAS), mitogen-activated protein kinase/extracellular signal-regulated kinase kinase (MEK), extracellular signal-regulated kinase (ERK), and c-Jun N-terminal kinase and in the significant reduction of apoptosis-inhibited molecule Fas associated death domain protein-like interleukin-1 beta-convening enzyme inhibitory protein and cellular inhibitor of apoptosis protein-1 in K562 cells.

CONCLUSIONSHU enhanced K562 cell sensitivity to rsTRAIL is mediated by Ras-MEK-ERK signaling pathway. Expression of antiapoptotic proteins cellular Fas associated death domain protein-like interleukin-1 beta-convening enzyme inhibitory protein and cellular inhibitor of apoptosis protein-1 is also down-regulated during this process. These results may through light on the therapeutic study of human chronic myelogenous leukemia.

Apoptosis ; drug effects ; physiology ; CASP8 and FADD-Like Apoptosis Regulating Protein ; metabolism ; Humans ; Hydroxyurea ; pharmacology ; Inhibitor of Apoptosis Proteins ; metabolism ; K562 Cells ; MAP Kinase Signaling System ; TNF-Related Apoptosis-Inducing Ligand ; pharmacology

TNF-related apoptosis inducing ligand (TRAIL) expressions were studied in primary human brain astrocytes in response to pro-inflammatory cytokines. When astrocytes were treated with IL-1beta TNF-alphaor IFN-gamma TRAIL was induced in cultured fetal astrocytes. In particular, IFN-gammainduced the highest levels of TRAIL in cultured astrocytes. When astrocytes were pre-reated with IFN-gamma they induced apoptosis in TRAIL-sensitive Peer cells. Our results suggest that IFN-gamma modulates the expression of TRAIL in astrocytes, which may enhance cytotoxic sensitivity of infiltrating immune cells or brain cells other than astrocytes during inflammation of brain.
Tumor Necrosis Factor-alpha/genetics/*metabolism ; TNF-Related Apoptosis-Inducing Ligand ; Membrane Glycoproteins/genetics/*metabolism ; Interferon Type II/*pharmacology ; Humans ; Cells, Cultured ; Astrocytes/*cytology/drug effects/metabolism ; Apoptosis Regulatory Proteins/genetics/*metabolism ; Apoptosis/*drug effects/physiology ; Antineoplastic Agents/*pharmacology

TNF-related apoptosis inducing ligand (TRAIL) expressions were studied in primary human brain astrocytes in response to pro-inflammatory cytokines. When astrocytes were treated with IL-1beta TNF-alphaor IFN-gamma TRAIL was induced in cultured fetal astrocytes. In particular, IFN-gammainduced the highest levels of TRAIL in cultured astrocytes. When astrocytes were pre-reated with IFN-gamma they induced apoptosis in TRAIL-sensitive Peer cells. Our results suggest that IFN-gamma modulates the expression of TRAIL in astrocytes, which may enhance cytotoxic sensitivity of infiltrating immune cells or brain cells other than astrocytes during inflammation of brain.
Tumor Necrosis Factor-alpha/genetics/*metabolism ; TNF-Related Apoptosis-Inducing Ligand ; Membrane Glycoproteins/genetics/*metabolism ; Interferon Type II/*pharmacology ; Humans ; Cells, Cultured ; Astrocytes/*cytology/drug effects/metabolism ; Apoptosis Regulatory Proteins/genetics/*metabolism ; Apoptosis/*drug effects/physiology ; Antineoplastic Agents/*pharmacology

Human tumor necrosis factor-related apoptosis-inducing ligand(TRAIL) is a member of the tumor necrosis factor (TNF) family of ligands which has been reported in 1995. The TRAIL protein induces apoptosis of certain types of target cells, such as transformed cells that include but are not limited to cancer cells and virus-infected cells but the normal cells. It is a type II transmembrane protein and the extracellular domain of TRAIL is the functional domain in induction of cell apoptosis. A gene fragment encoding for the active domain of TRAIL was modified with oligo-nucleotide directed mutagenesis according to the characters of Pichia pastoris expressing vector. Arginine at the position of 149 corresponding to the amino acid residue 531 which might be a potential Kex2 protease processing sites was substituted with Lysine to prevent the expressed protein from the digestion by the protease. After proved with DNA sequencing. the modified gene fragment coding soluble TRAIL domain was inserted into the Pichia pastoris expression vector pPIC9K in the same reading frame with alpha-factor secreting signal peptide. The recombinant plasmid pPIC9K - TRAIL was transferred into P. pastoris cell by spheroplast transformation. The recombinant yeasts were identified by antibiotic G418 and Southern dot blot. The transformants (His+ Mut(s)) containing multi-copy gene fragment of TRAIL were selected with increasing concentration of G418 and induced with 0.5% methanol in shaking flask to expression the active domain of TRAIL. After inducing for 3 - 4 days, the proteins in the culture supernatant was assayed with SDS-PAGE and Western blot. Two expressed protein bands whose appearant molecular weight were 19kD and 38kD, respectively, could be specifically recognized by polyclonal antibodies against human TRAIL. The 38kD protein might be a dimers of TRAIL in the culture supernatant. The amount of expressed foreign protein made up to 36% of the total proteins in the culture suprenatant. Biological activity assay, in vitro, indicated that the expressed protein could induce tumor cells apoptosis.
Apoptosis ; drug effects ; Cell Line, Tumor ; Electrophoresis, Polyacrylamide Gel ; Genetic Vectors ; genetics ; Humans ; Immunohistochemistry ; Pichia ; genetics ; metabolism ; Protein Structure, Tertiary ; genetics ; physiology ; TNF-Related Apoptosis-Inducing Ligand ; genetics ; metabolism ; pharmacology

OBJECTIVEThe aim of this study was to investigate whether the induction of caspase-8 by γ-interferon (IFNγ) renders neuroblastoma (NB) cells sensitive to tumor necrosis factor related apoptosis inducing ligand(TRAIL).

METHODSCaspase-8 mRNA expression was determined by RT-PCR. The effects of IFNγ, TRAIL, IFNγ +TRAIL and caspase-8 inhibitor+ TRAIL on the growth and apoptosis of NB cells were detected with the methods of reduction rate of Alamar Blue assay and flow cytometry. The relative caspase-8 activity was measured with colorimetric assay.

RESULTSCaspase-8 expression was detectable in CHP212 cells which were sensitive to TRAIL, with an increased expression after treatment with IFNγ. Caspase-8 was undetectable in SH-SY5Y(SY5Y) cells which were resistant to TRAIL, but an increased expression of caspase-8 mRNA was found after treatment with IFNγ. Moreover, TRAIL combined with IFNγ induced apoptosis in SY5Y cells. The relative caspase-8 activity of CHP212 cells increased with the prolonged TRAIL action time. The relative caspase-8 activity of SY5Y cells in the IFNγ+TRAIL group was significantly higher than those of the control, IFNγ, TRAIL and inhibitor groups.

CONCLUSIONSNB cells expressing caspase-8 are sensitive to TRAIL. TRAIL induces apoptosis in NB cells with an increase of relative caspase-8 activity.

Apoptosis ; drug effects ; Caspase 8 ; physiology ; Cell Line, Tumor ; Flow Cytometry ; Humans ; Interferon-gamma ; pharmacology ; Neuroblastoma ; drug therapy ; pathology ; Reverse Transcriptase Polymerase Chain Reaction ; TNF-Related Apoptosis-Inducing Ligand ; pharmacology

OBJECTIVETo evaluate the expression and activity of TNF-related apoptosis-inducing ligand (TRAIL) gene expressed from the hTERT promoter on colon cancer cell line HT-29.

METHODSGFP/TRAIL gene expressed from the hTERT promoter was transfected into HT-29 with adenoviral vectors system, expression and apoptosis inducing ability of GFP/TRAIL protein were determined with fluorescence-activated cell sorting (FACS) method.

RESULTSThe expression of GFP gene was 31.4 % and 67.0 % with either hTERT promoter or CMV promoter in DLD1 cells; GFP/TRAIL gene was able to inhibit cell growth (74.2%) and induce apoptosis (25.8%) of HT-29 cells. There was significant difference between Ad/hTERT-gTRAIL and the other two control groups (PBS and Ad/CMV-GFP, P<0.05).

CONCLUSIONThe GFP/TRAIL gene with hTERT promoter transfected by adenoviral vector was successfully expressed in HT-29 cell, which can both inhibit cell growth and induce apoptosis of colon cancer cell line HT-29.

Adenoviridae ; genetics ; Apoptosis ; physiology ; Colonic Neoplasms ; enzymology ; pathology ; Genetic Vectors ; Green Fluorescent Proteins ; biosynthesis ; genetics ; HT29 Cells ; Humans ; Promoter Regions, Genetic ; genetics ; TNF-Related Apoptosis-Inducing Ligand ; biosynthesis ; genetics ; Telomerase ; genetics ; Tumor Cells, Cultured