OBJECTIVETo investigate the effect of tumor necrosis factor related apoptosis inducing ligand (TRAIL) and its receptor on apoptosis in thymus during early post-burn stage in rat with severe burns.

METHODSFifty Wistar rats were randomly divided into sham scald group (SS, n = 10) and burn group (n = 40). The apoptosis in thymus in rats was detected with annexin V/FITC-PI double staining at 4, 12, 24, 48 post-burn hours (PBH). The expression of TRAIL death receptor DR5, DR4 and its decoy receptor DcR1, DcR2 in thymus were detected by RT-PCR and Western blot at above time-points.

RESULTSCompared with that in SS group (6.7 +/- 0.8)%, the apoptosis in the thymus in burn group started to increase at 4 PBH [(17.1 +/- 0.4)%], peaked at 12 PBH [(25.2 +/- 1.1)%], and it was still evidently higher than that in SS group at 48 PBH (P < 0.05). There was no obvious difference in the apoptosis rate in rats in burn group among all the time-points. The expression of DR5 in burn group at each time-points was significantly higher than those in SS group, while that of DcR2 shown an opposite tendency (P < 0.05). The expression of DR4, DcR1 was similar in both groups.

CONCLUSIONThe marked increase in apoptosis rate in rat thymus at early post-burn stage, and the significant change in the expression of DR5 and DcR2 show that TRAIL pathway may participate in apoptosis.

Animals ; Apoptosis ; Burns ; metabolism ; Disease Models, Animal ; Female ; Male ; Rats ; Rats, Wistar ; Receptors, TNF-Related Apoptosis-Inducing Ligand ; genetics ; metabolism ; TNF-Related Apoptosis-Inducing Ligand ; genetics ; metabolism ; Thymus Gland ; metabolism

OBJECTIVETo investigate the molecular mechanism of doxorubicin enhancement of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) inducing apoptotic effect on multiple myeloma cell line KM3.

METHODSApoptosis was studied independently through flow cytometry analysis and TUNEL staining. The expression of death receptor 5 (DR5) and nuclear factor P65 in nuclear was examined by Western blot.

RESULTSThe apoptosis ratio of KM3 cells was 20.88%, 40.03%, 57.87%, 60.82% respectively when treated with different concentration of TRAIL (10, 20, 50, 100 ng/ml) combining with doxorubicin. It is markedly higher than the group treated with TRAIL or doxorubicin alone. DR5 expression increased while P65 decreased as the doses of doxorubicin increased when KM3 cells treated with doxorubicin (0.5, 1.0, 2.0 and 4.0 microg/ml) plus 20 ng/ml TRAIL.

CONCLUSIONIncreasing the expression of DR5 and nuclear transferring of P65 are the important molecular mechanism by which doxorubicin enhances TRAIL-inducing apoptosis of KM3 cells.

Apoptosis ; drug effects ; Cell Line, Tumor ; Doxorubicin ; pharmacology ; Drug Interactions ; Humans ; Multiple Myeloma ; metabolism ; pathology ; Receptors, TNF-Related Apoptosis-Inducing Ligand ; genetics ; metabolism ; TNF-Related Apoptosis-Inducing Ligand ; pharmacology ; Transcription Factor RelA ; genetics ; metabolism

OBJECTIVETo detect the expression of TRAIL protein and mRNA in hemangiomas and vascular malformations.

METHODSSections of 33 proliferative hemangiomas,28 involuting hemangiomas and 29 vascular malformations were immunostained for TRAIL protein, TRAIL mRNA was examined by in situ hybridization in these tissue.

RESULTSThe TRAIL protein positive rates in proliferative hemangiomas, involuting hemangiomas, vascular malformations and normal skins were respectively 45.45% (15/33), 78.57% (22/28), 0% and 0%. There were significant differences among the four pathologies (P < 0.01). The difference between proliferative hemangiomas and involuting hemangiomas was also significant (P < 0.01). The TRAIL mRNA positive rates were 66.67% (11/33), 89.29 (25/28), 0% and 0% respectively. There were also significant differences among the four pathologies (P < 0.01). The difference between proliferative hemangiomas and involuting hemangiomas was also significant (P < 0.01).

CONCLUSIONSTRAIL could induce endothelial apoptosis and cause regression of hemangiomas.

Apoptosis ; Female ; Hemangioma ; metabolism ; pathology ; Humans ; In Situ Hybridization ; Infant, Newborn ; Male ; Microcirculation ; RNA, Messenger ; genetics ; TNF-Related Apoptosis-Inducing Ligand ; genetics ; metabolism ; Vascular Malformations ; metabolism ; pathology

OBJECTIVETo study the effect of recombinant tumor necrosis factor-related apoptosis-inducing ligand(TRAIL) on the expression of apoptosis and inflammatory related genes in human colon cancer cell line HCT-116.

METHODSAfter 24-hour treatment with recombinant human TRAIL protein, the expressions of apoptosis-related genes(Bcl-2, Bad, caspase-3, and caspase-8) and inflammation-related genes(TNF-α, IL-1β, and COX-2) were measured by real-time PCR and appropriate kits in HCT-116.

RESULTSAfter treatments of 10 μg/L and 100 μg/L recombinant human TRAIL proteins, the apoptotic rates of HCT-116 cells were 27.4% and 45.9%, respectively. Expressions of anti-apoptosis gene Bcl-2, pro-apoptosis gene Bad and apoptotic markers caspase-3 and caspase-8 were significantly up-regulated, which was more significant in the group of 100 μg/L treatment(P<0.05). Moreover, after TRAIL treatments, expressions of inflammation-related genes TNF-α, IL-1β, COX-2 were also dramatically increased, and 100 μg/L treatment group showed higher up-regulation(P<0.05).

CONCLUSIONSRecombinant TRAIL protein induces both apoptosis and inflammation of human colon cancer cells.

Apoptosis ; drug effects ; Apoptosis Regulatory Proteins ; genetics ; metabolism ; Colonic Neoplasms ; metabolism ; pathology ; HCT116 Cells ; Humans ; Inflammation ; Recombinant Proteins ; pharmacology ; TNF-Related Apoptosis-Inducing Ligand ; pharmacology

OBJECTIVESTo investigate the mechanisms for human telomerase reverse transcriptase (hTERT) RNA interference (RNAi) in increasing hepatocellular carcinoma cell apoptosis induced by TNF-related apoptosis-inducing ligand (TRAIL).

METHODSCell apoptosis was identified by flow cytometry analysis after annexin V/PI double staining. Expression of apoptosis-related proteins, procaspase-8, -9, -3, Bax, Bcl-2 and hTERT, were identified by Western blotting analysis; telomerase activity and telomere length were detected by telomeric repeat amplification protocol (TRAP) and telomere amount and length assay (TALA) methods.

RESULTSHepatocellular carcinoma cell apoptosis induced by TRAIL were all significantly increased by hTERT RNAi (P less than 0.05). For example, apoptosis rates were enhanced from 5.53% (untransformed) to 10.35% (transformed) in HepG 2 cells and from 14.73% to 77.24% in SMMC 7721 cells after being treated by 100 ng/ml TRAIL for 24 h. Moreover, activation of procaspase-8, -9 and -3 in transformed cells after being treated by TRAIL were all significantly raised (P less than 0.05) in a dose-dependent manner. The expression of procaspase-8, -9 and Bcl-2 were effectively augmented (P less than 0.05), but expressions of Bax and hTERT were strikingly decreased (P less than 0.05). Meanwhile, telomerase activity was apparently suppressed and telomere length was markedly shortened (P less than 0.05). There were no remarkable differences in these effects between control cells and the untransformed cells (P more than 0.05).

CONCLUSIONEnhanced cell apoptosis induced by TRAIL through hTERT RNAi may be related to up-regulation of procaspase-8 and -9 expressions. However the down-regulation of hTERT expression, reduced telomerase activity and shortened telomere length may not be related to expressions of Bcl-2 and Bax.

Apoptosis ; Carcinoma, Hepatocellular ; pathology ; Caspase 8 ; metabolism ; Caspase 9 ; metabolism ; Cell Line, Tumor ; Humans ; Liver Neoplasms ; pathology ; RNA Interference ; TNF-Related Apoptosis-Inducing Ligand ; pharmacology ; Telomerase ; genetics ; metabolism

Human tumor necrosis factor-related apoptosis-inducing ligand (hTRAIL) might be developed as a novel anti-tumor drug due to its selective cytotoxicity in tumor cells. The predicted Macaca mulatta TRAIL (mmTRAIL) is highly homologous to hTRAIL in nucleotide acid as well as amino acid sequence, suggesting that mmTRAIL might induce apoptosis of human cancer cells. However, the cytotoxicity of mmTRAIL in human cancer cells has not been investigated. In this paper, it is reported that the gene encoding mmTRAIL has been cloned by using reverse-transcriptase polymerase chain reaction (RT-PCR) from monkey peripheral blood mononuclear cells (PBMCs) in our laboratory. Subsequently, an expression plasmid was constructed by inserting mmTRAIL gene into pQE30 plasmid. After induction by addition of Isopropyl β-D-1-Thiogalactopyranoside (IPTG), mmTRAIL was expressed. MmTRAIL was recovered from supernatant of sonicated bacteria by Ni-NTA agarose affinity chromatography. SDS-PAGE and gel filtration chromatography demonstrated that mmTRAIL forms trimer in solution. In vitro assays indicated that mmTRAIL was cytotoxic to human COLO205 tumor cells but not to normal cells at low concentration of nanomole. In addition, antitumor effect of mmTRAIL was evaluated in mice bearing human COLO205 tumor xenografts. Intratumorally injected mmTRAIL significantly inhibited growth of tumor grafts. These results suggested that mmTRAIL was valuable as candidate drug for cancer-targeted therapy.
Animals ; Antineoplastic Agents ; Apoptosis ; Cell Line, Tumor ; Cloning, Molecular ; Humans ; Leukocytes, Mononuclear ; Macaca mulatta ; Mice ; Plasmids ; TNF-Related Apoptosis-Inducing Ligand ; genetics ; metabolism ; Xenograft Model Antitumor Assays

Tumor necrosis factor-related apoptosis-induced ligand (TRAIL) induces apoptosis selectively in cancer cells while sparing normal cells. However, many cancer cells are resistant to TRAIL-induced cell death. Here, we report that paxilline, an indole alkaloid from Penicillium paxilli, can sensitize various glioma cells to TRAIL-mediated apoptosis. While treatment with TRAIL alone caused partial processing of caspase-3 to its p20 intermediate in TRAIL-resistant glioma cell lines, co-treatment with TRAIL and subtoxic doses of paxilline caused complete processing of caspase-3 into its active subunits. Paxilline treatment markedly upregulated DR5, a receptor of TRAIL, through a CHOP/GADD153-mediated process. In addition, paxilline treatment markedly downregulated the protein levels of the short form of the cellular FLICE-inhibitory protein (c-FLIPS) and the caspase inhibitor, survivin, through proteasome-mediated degradation. Taken together, these results show that paxilline effectively sensitizes glioma cells to TRAIL-mediated apoptosis by modulating multiple components of the death receptor-mediated apoptotic pathway. Interestingly, paxilline/TRAIL co-treatment did not induce apoptosis in normal astrocytes, nor did it affect the protein levels of CHOP, DR5 or survivin in these cells. Thus, combined treatment regimens involving paxilline and TRAIL may offer an attractive strategy for safely treating resistant gliomas.
Antineoplastic Agents/*pharmacology ; Apoptosis/*drug effects ; Astrocytes/metabolism ; CASP8 and FADD-Like Apoptosis Regulating Protein/genetics/*metabolism ; Caspase 3/metabolism ; Cell Line, Tumor ; Drug Discovery ; Flow Cytometry ; Glioma/*metabolism/pathology ; Humans ; Indoles/*pharmacology ; Inhibitor of Apoptosis Proteins/metabolism ; RNA, Small Interfering ; Receptors, TNF-Related Apoptosis-Inducing Ligand/genetics/metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; TNF-Related Apoptosis-Inducing Ligand/metabolism/*pharmacology ; Transcription Factor CHOP/analysis

Escherichia coli was genetically engineered to produce recombinant tumor necrosis factor-related apoptosis inducing ligand (Apo2L/TRAIL) using a temperature-inducible expression system. To create a fed-batch culture condition that allows efficient production of TRAIL, different feeding strategy including discontinuous, DO-stat and pH-stat feeding strategies were compared. Then, a special 2-stage feeding strategy was developed. High concentration of biomass (300g wet cell weight per liter of culture broth) and active soluble TRAIL protein (1.1g/L) was obtained by applying a high-cell-density cultivation procedure with the 2-stage feeding strategy. Cultivation of recombinant E. coli was started as a batch process at 30 degrees C and then followed by fed-batch culture when the dissolved oxygen concentration presented a steep increase resulted from the exhaustion of glucose in the medium. At the first phase of fermentation (batch phase), agitation rate was enhanced to control dissolved oxygen at 30 percent. When glucose in the medium was used up, indicated by a sudden rise in pH value and dissolved oxygen, the second phase (fed-batch phase) was started with glucose and nitrogen resource being supplied automatically. At the beginning of fed-batch operation, stirrer rate was cascaded with dissolved oxygen signals to keep it at 20 percent (DO-stat). During the fed-batch phase, glucose was limited to control the specific growth rate under the critical value microcrit, to avoid acetic acid excretion. When the stirrer speed arrived at its up-limit, the flow rate of feed was kept constant. In the inducing phase(42 degrees C for 4h) glucose was fed as a pH regulating agent (pH-stat) and the specific growth rate and dissolved oxygen decreased sharply. Aqueous ammonia was used for maintaining pH value at 7.0 throughout the first two phases. In the whole fermentation, acetic acid concentration didn't exceed 2.9 g/L. At the end of the high-cell-density cultivation process, no acetic acid could be detected in the medium. These results indicated that our fed-batch strategy was able to prevent acetate accumulation significantly. Although high cell density has been achieved, the induction process was not optimized satisfactorily and much work should be done further. Furthermore, since no special ways, like pure oxygen, pressure, has been used in our experiments, this efficient approaches would be useful not only in a pilot scale but also in an industry scale. Finally, simple purification procedure based on immobilized metal affinity column (IMAC) and CM-Sepharose column was implemented to isolate the TRAIL. Yields of more than 800mg TRAIL per liter of culture broth were obtained, the final purity reaching more than 95%. The purified TRAIL showed strong cytotoxity activity against human pancreatic 1990 tumor cells, with ED50 about 1.6 microg/mL.
Escherichia coli ; genetics ; growth & development ; metabolism ; Fermentation ; Genetic Engineering ; methods ; Humans ; Recombinant Proteins ; biosynthesis ; chemistry ; isolation & purification ; TNF-Related Apoptosis-Inducing Ligand ; biosynthesis ; genetics

There exist two major apoptotic signaling pathways: the intrinsic mitochondria-mediated pathway, and the extrinsic death receptor-induced pathway. TNF-related apoptosis-inducing ligand (TRAIL), which is the ligand for death receptor 4 (DR4) and death receptor 5 (DR5) and induces apoptosis by ligation with DR4 or DR5. We review the characteristic of TRAIL and its receptors, the mechanism of apoptosis induced by TRAIL, the distribution of death receptors in cancer, and applications and prospects of TRAIL signaling pathway in the treatment of cancer.
Animals ; Antineoplastic Agents ; pharmacology ; therapeutic use ; Apoptosis ; drug effects ; Drug Delivery Systems ; GPI-Linked Proteins ; genetics ; metabolism ; Genetic Therapy ; Humans ; Neoplasms ; metabolism ; pathology ; therapy ; Receptors, TNF-Related Apoptosis-Inducing Ligand ; classification ; genetics ; metabolism ; Receptors, Tumor Necrosis Factor, Member 10c ; Signal Transduction ; TNF-Related Apoptosis-Inducing Ligand ; genetics ; metabolism ; pharmacology ; Tumor Necrosis Factor Decoy Receptors ; genetics ; metabolism

OBJECTIVETo clone and identify novel proteins binding to the death domain of the death receptor 4 (DR4).

METHODSThe yeast two-hybrid system was used for this study. Automatic sequencing was carried out for DNA sequencing. The sequence homology and the functional domains were analyzed by BLAST and the ScanProsite Tool softwares, respectively. Co-immunoprecipitate method was used to confirm human formyl peptide receptor-like 1 (FPRL1) binding specifically with DR4CD (the cytoplasmic domain of DR4) in HEK293T cells.

RESULTSTwo positive clones, named as pADB1 and pADB2, were obtained. BLAST searching showed that the homology of the insert sequence of pADB1 with the mRNA of FPRL1 was 97%. The insert of pADB2 shared no homology with any known peptides in GeneBank. Co-immunoprecipitate analysis further confirmed that FPRL1 could bind to DR4CD in vivo specifically.

CONCLUSIONSFPRL1 may associate with DR4CD in vivo specifically. The functional studies of FPRL1 in signaling pathway mediated by TNF-related apoptosis inducing ligand (TRAIL) are in active progress in our laboratory.

Amino Acid Sequence ; Apoptosis ; Apoptosis Regulatory Proteins ; Base Sequence ; Carrier Proteins ; biosynthesis ; genetics ; Cloning, Molecular ; Humans ; Membrane Glycoproteins ; metabolism ; Molecular Sequence Data ; Protein Structure, Tertiary ; Receptors, Formyl Peptide ; metabolism ; Receptors, Lipoxin ; metabolism ; Receptors, TNF-Related Apoptosis-Inducing Ligand ; Receptors, Tumor Necrosis Factor ; genetics ; metabolism ; Signal Transduction ; TNF-Related Apoptosis-Inducing Ligand ; Tumor Necrosis Factor-alpha ; metabolism