Induction of apoptosis by recombinant soluble human TRAIL in Jurkat cells.

OBJECTIVE: To investigate the therapeutic potential of tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL), a member of the TNF superfamily, and to analyze TRAIL-induced apoptosis in Jurkat cells. METHODS: Expression of TRAIL receptors (DR4 and DR5) was detected by reverse transcriptase-polymerase chain reaction (RT-PCR). Cytotoxic effects were determined by colony formation assay and a cell counting kit. The effects of recombinant TRAIL on apoptosis of Jurkat cells were determined by DNA fragmentation (DNA ladder) and PI staining. Changes in mitochondrial membrane potential were detected with JC-1 fluorescence. RESULTS: TRAIL inhibited the proliferation and induced internucleosomal DNA fragmentation (characteristic of apoptosis) and loss of mitochondrial membrane potential. CONCLUSION: Recombinant soluble TRAIL can be used as a therapy for cancer.

[Cloning, expression and purification of human TNF-related apoptosis-inducing ligand in Escherichia coli].

OBJECTIVE: To clone human tumor necrosis factor-related apoptosis-inducing ligand (TRAIL, 114-281) cDNA and develop an inducible system for expression in E. coli. METHODS: The human TRAIL (114-281) cDNA was amplified with the total RNA from the human peripheral blood monocytes by RT-PCR. The cDNA was inserted into pMD T vector. The selected integrants were confirmed by PCR screen, digestion with restriction enzymes and DNA sequencing. Then, the insert of human TRAIL cDNA was subcloned into prokaryotic expression vector pET28a. The construction of prokaryotic expression vector was proofed correct by RT-PCR and digestive identification. The recombinant protein was induced by IPTG (isopropyl-beta-D-thiogalactopyranoside) . The sTRAIL inclusion bodies were refolded by dilution method. Refolded protein was purified with column chromatography. RESULTS: Agarose gel electrophoresis of product of RT-PCR revealed a band around 500bp, which was expected. The positive integrants were confirmed by PCR screen and digestion with restriction enzymes. The same band as RT-PCR product was showed by PCR screen and digestion with restriction enzymes. Then the selected integrants were confirmed by DNA sequencing. The sequence was checked in GenBank. The construction of prokaryotic expression vector pET 28a was proofed correct by RT-PCR and digestive identification. TRAIL protein was successfully induced by IPTG in E. coli BL21. The results also showed that the protein was expressed as inclusion bodies. After the sTRAIL inclusion bodies were solubilized and refolded, the protein expressed was purified with one band, which was about 20kD, analyzed by SDS-PAGE. CONCLUSION: These results suggested that the hsTRAIL was cloned, expressed and purified in the present study. Significant quantities of TRAIL produced by this method should allow further studies in determining the physiological significance and function of TRAIL in the future.

[Coix lachryma jobi L varma-yuan induces apoptosis of jurkat cell line in acute T lymphoblast leukemia and its mechanism].

The aim of the present study was to investigate the anti-proliferation and pro-apoptosis effect of Coix lachrymajobi L varma-yuan on acute T lymphoblast leukemia cell line Jurkat cells and its mechanism. Jurkat cells were treated with Coix lachrymajobi L varma-yuan of various concentrations (0, 0.4, 0.8, 1.6 mg/ml) for 24h. The inhibitory ratio was measured by Cell Counting Kit-8. The effects of Coix lachrymajobi L varma-yuan on apoptosis of Jurkat cells were determined by Hoechst 33258, PI and Annexin V-FITC/PI double staining. The mitochondrial membrane potential was analyzed by JC-1 staining. The results demonstrated that Coix lachrymajobi L varma-yuan inhibited the proliferation of Jurkat cells, and induced chromatin condensation and fragmentation (characteristic of apoptosis) and loss of mitochondrial membrane potential. In conclusion, Coix lachrymajobi L varma-yuan can inhibit the cell proliferation and induce the apoptosis of Jurkat cells. These effects relate to loss of mitochondrial membrane potential. These results suggest that Coix lachrymajobi L varma-yuan may be of value in treating lymphoma.

[Effects of triptolide on proliferation and apoptosis of Jurkat cell line in acute T lymphocytic leukemia].

The aim of this study was to investigate the anti-proliferation and pro-apoptosis of triptolide on Jurkat cell line in acute T lymphocytic leukemia. The Jurkat cells were treated with various concentrations of triptolide (0, 1, 2, 4, 8, 16 microg/L) for 12 hours. The inhibitory ratio was measured by Cell Counting Kit-8 assay. The effects of triptolide on apoptosis of Jurkat cells were determined by DNA fragmentation (DNA ladder), Hoechst 33258, PI and Annexin V-FITC/PI double staining. The results demonstrated that triptolide inhibited the proliferation of Jurket cells. The 50% inhibitory concentration (IC(50)) was 4.0 microg/L. Chromatin condensation in the cells treated with triptolide could be seen by light microscopy. DNA electrophoresis showed evidence of nuclear fragmentation (DNA ladder). The hypoploid (sub-G(1)) population was increased after treatment with triptolide. The translocation of phosphatidylserine at the outer surface of the cell plasma membrane could be induced by triptolide. After treatment with triptolide for 12 hours, the rates of apoptotic cells were significantly increased. Moreover, these pro-apoptosis effects were in time-dependent manner. It is concluded that triptolide can inhibit the proliferation and induce the apoptosis of Jurkat cells. This study provides experimental basis for clinical use of triptolide in leukemia therapy.