Molecular mechanism of hydroxyurea enhances K562 cell apoptosis induced by tumor necrosis factor-related apoptosis-inducing ligand / 中国医学科学院学报

<p><b>OBJECTIVE</b>To 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).</p><p><b>METHODS</b>Chronic 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.</p><p><b>RESULTS</b>The 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.</p><p><b>CONCLUSIONS</b>HU 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.</p>

Combination of AD5-10 and epirubicin in treating rheumatoid arthritis / 中国医学科学院学报

<p><b>OBJECTIVE</b>To investigate the mechanism of anti-death receptor 5-10 (AD5-10) combined with epirubicin in treating rheumatoid arthritis (RA).</p><p><b>METHODS</b>We detected the cell viability of the fibroblast-like synoviocytes (FLS) from RA patients with MTT. The expression level of apoptosis signaling pathways protein, p53, and p21 were evaluated with Western blot.</p><p><b>RESULTS</b>We found that epirubicin, at different doses, could enhance the effect of AD5-10 on FLS, promoting the apoptosis of FLS. The expression levels of caspase-3, -8, -9, c-FLIP, Bcl-2, p53, and p21 in the FLS changed after epirubicin treatment.</p><p><b>CONCLUSION</b>Epirubicin may coordinate with AD5-10 in inducing FLS apoptosis through affecting the levels of p53, p21, c-FLIP, and Bcl-2.</p>

Construction and expression of anti-tumor necrosis factor related apoptosis-inducing ligand receptor death receptor 5 chimeric antibody in eukaryotic cells / 中国医学科学院学报

<p><b>OBJECTIVE</b>To construct the human/mouse chimeric antibody of a functional anti-death receptor 5 (DR5) antibody. Methods The viable region of light chain (VL) and viable region of heavy chain (VH) genes of anti-DR5 antibody were amplified and cloned into the light- and heavy-chain expression vectors respectively, then the recombinant plasmids were co-transfected into dihydrofolate reductase(-) Chinese hamster ovary cell (CHO-dhfr(-)) for expression. The positive clone was screened by the two selective genes (neo and dhfr). The humanization and specificity of chimeric antibody was identified by ELISA and Western blotting, and the tumoricidal activity of the expressed chimeric antibody was detected by tetrazolium salt phenazine methosulfate assay.</p><p><b>RESULTS</b>The expression vectors stably expressed chimeric antibody in CHO-dhfr(-). In the cell supernatant of the F4' clone, the human IgG heavy constant region and light constant region were identified. Moreover, the secreted chimeric antibody retained the binding capacity to the antigen (DR5) and decreased the cell viability of Jurkat and HCT116 cells to 73.15% and 77.30% in vitro respectively.</p><p><b>CONCLUSION</b>The human/mouse anti-DR5 chimeric antibody has been successfully expressed in eukaryotic cells and shows tumoricidal activity, which establishes a foundation for the future research of humanized antibody medicine.</p>

Identification of binding proteins to the PDZ domain of ERBIN / 中国医学科学院学报

<p><b>OBJECTIVE</b>To identify the binding proteins to PDZ domain of ERBIN.</p><p><b>METHODS</b>Using PDZ domain of ERBIN as the bait, yeast two-hybrid technology was employed to screen the human lymphocyte leukemia cells MATCHMAKER cDNA library. The protein interaction was identified by immunoprecipitation.</p><p><b>RESULTS</b>A PDZ-binding protein, TAX1, was identified.</p><p><b>CONCLUSION</b>TAX1 is a novel binding protein to PDZ domain of ERBIN.</p>

Mechanisms of sensitization by 8-chloro-adenosine of human tumor cells to TRAIL-induced apoptosis / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To study the effect of 8-chloro-adenosine (8-Cl-Ado) on the sensitivity of human hepatoma and breast cancer cell lines to TRAIL-induced apoptosis in vitro and its mechanisms.</p><p><b>METHODS</b>Recombinant soluble TRAIL (rsTRAIL) or 8-Cl-Ado was used to treat hepatoma cell line BEL-7402 and breast cancer cell line MCF-7 in vitro. MTT assay was used to evaluate cell viability. The effect of cotreatment with rsTRAIL and 8-Cl-Ado was analyzed. NF-kappaB activity reporter plasmid was designed to measure the activity of transcription factor NF-kappaB. After transient transfection with the reporter plasmid, which contains NF-kappaB-responsive elements, into the cell lines, cells were treated with rsTRAIL and/or 8-Cl-Ado, then the activity of the reporter gene luciferase was determined. Different kinds of caspase inhibitors were used to measure the effect of caspases in the rsTRAIL and/or 8-Cl-Ado induced apoptosis.</p><p><b>RESULTS</b>8-Cl-Ado could greatly enhance sensitivity of BEL-7402 and MCF-7 cells to reTRAIL. Treatment with 8-Cl-Ado and rsTRAIL inactivated transcription factor NF-kappaB and induced apoptosis in BEL-7402, but not in MCF-7. Caspase family inhibitor could not prevent apoptosis induced by 8-Cl-Ado and rsTRAIL in BEL-7402 cells, however, it could block apoptosis in MCF-7 cells, indicating that two different apoptosis pathways in MCF-7 and BEL-7402 might exist, one was caspase dependent and the other caspase independent. Moreover, all of the inhibitors of caspse-3, -8 and -9 could not block apoptosis induced by the co-treatment.</p><p><b>CONCLUSION</b>8-chloro-adenosine can enhance the sensitivity of human hepatoma cell line BEL-7402 and breast cancer cell line MCF-7 to rsTRAIL, even though MCF-7 is TRAIL-resistant. 8-Cl-Ado combined with rsTRAIL can trigger different signal pathways in MCF-7 and BEL-7402, which are caspase dependent and independent, respectively.</p>

Establishment of high-throughput drug screening model targeting retinoic acid receptor in cells / 药学学报

<p><b>AIM</b>To screen new drug for the treatment of acute promyelocytic leukemia, psoriasis and acne, high-throughput drug screening cell models marked by green fluorescent protein (GFP) have been established.</p><p><b>METHODS</b>Eight repeats of retinoic acid response element (RARE) were synthesized and cloned into a GFP expression vector. This construct was stably transfected into cells in vitro. Stable and sensitive cell clones with high copy numbers of RARE were selected by retinoic acid (RA) using fluorescence-activated cell sorting (FACS).</p><p><b>RESULTS</b>A cell line has been chosen to be high-throughput drug screening cell model. This model was shown with low background, high sensitive and good reproducibility, and was convenient and inexpensive.</p><p><b>CONCLUSION</b>This drug screening cell model can be used for retinoic acid receptor target high-throughput drug screening.</p>

Chemotherapeutic drugs enhanced rsTRAIL tumoricidal activity / 中国医学科学院学报

<p><b>OBJECTIVE</b>To explore the role and mechanisms of chemotherapeutic drugs in TRAIL induced cell death.</p><p><b>METHODS</b>Tumoricidal activities of the chemotherapeutic drugs and/or rsTRAIL in 13 strains of tumor cell lines were evaluated by MTS-PMS assay and flow cytometry. DR5 expression in the cells was observed by Western blot.</p><p><b>RESULTS</b>The apoptosis of human promyelocytic leukemia cells HL-60, liver cancer cells BEL-7402, T-acute lymphoblastic leukemia cells Jurkat, and myeloid leukemia cells K562 treated with rsTRAIL at 0.5 microg/ml were 53.20%, 52.20%, 51.54%, 52.70%, and 41.00%, respectively, while that of the embryonal spleen cells 293 was 24.00%. However, the apoptosis percentages of lung cancer cells anti 973, breast cancer cells MCF-7, Chinese hamster ovarian cancer cells COS-7, neuroglialoma cells U251, neuroblastoma cells SH-SY5Y, glioma cells BT-325, rat pheochromocytoma cells PC12, and mouse adrenal epithelial cells NIH3T3 were all less than 10% under the same conditions. The sensitivity of central neuron cells of SH-SY5Y, PC-12, U251, BT3251, and human embryonal spleen cells 293, which were not sensitive to rsTRAIL challenges, increased remarkably after treatment with CHX, CP, and 8-CA at sub-toxic doses plus rsTRAIL at 0.5 microg/ml. The expressions of DR5 were up-regulated and kept pace with the onset of apoptosis in the BEL-7402 liver cancer cells.</p><p><b>CONCLUSION</b>The chemotherapeutic drugs including CHX, CP, and 8-CA at sub-toxic doses can enhance antitumor activity of rsTRAIL.</p>

Differential expression of the genes in leukemia cell apoptosis induced by TRAIL / 中国医学科学院学报

<p><b>OBJECTIVE</b>To identify the genes differentially expressed in leukemia cell apoptosis induced by recombinant soluble tumor necrosis factor-related apoptosis inducing ligand (rsTRAIL).</p><p><b>METHODS</b>Suppression subtractive hybridization (SSH) and polymerase chain reaction (PCR) were used for the cloning and identification of the genes differentially expressed in the apoptotic Jurkat cells induced by TRAIL. Slot blot and Northern blot were used for the expression pattern analysis of the genes. Automatic DNA sequencing was used for DNA sequence analysis.</p><p><b>RESULTS</b>Six cDNA fragments differentially expressed in the Jurkat leukemia cells treated with TRAIL were found, in which four were inhibited and two were activated during the Jurkat cell apoptosis treated with TRAIL. Among which the five genes of A14, X1, D1, A23 and C5 were found at the first time by DNA sequencing and GeneBank database searching. So that they were registered in GeneBank as AW731601, AW731602, AW731603, AW731604 and BE239235, respectively. It was found that the gene D1 was expressed higher in Jurkat leukemia cells and MCF-7 breast cancer cells than that in K562 leukemia, 825 gastric cancer and 7721 liver cancer cells.</p><p><b>CONCLUSIONS</b>Five novel cDNA fragments were found, and among which D1 might be a tumor specific gene.</p>

The primary study on a novel protein binding to the death domain of the death receptor 4 / 中国医学科学院学报

<p><b>OBJECTIVE</b>To clone and identify novel proteins binding to the death domain of the death receptor 4 (DR4).</p><p><b>METHODS</b>The 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.</p><p><b>RESULTS</b>Two 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.</p><p><b>CONCLUSIONS</b>FPRL1 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.</p>