Effect of doxorubicin on TRAIL resistance and TRAIL receptor expression in lymphoma cell line SNK-6 cells / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To investigate the effect of doxorubicin on TRAIL resistance and TRAIL receptor expression in lymphoma cell line SNK-6 cells.</p><p><b>METHODS</b>SNK-6 cells treated with doxorubicin at different concentrations alone or in combination with tumor necrosis factor related apoptosis inducing ligand (TRAIL). Cell proliferation was evaluated by MTT assay. Apoptosis and the expression of TRAIL receptors were determined by flow cytometry.</p><p><b>RESULTS</b>MTT assay showed that treatment with 100 and 1000 ng/ml doxorubicin for 24 h, the survival rates of SNK-6 cells were (80.9 ± 7.2)% and (53.7 ± 2.8)%, significantly higher than that by treatment combined with 500 ng/ml TRAIL (64.9 ± 1.1)% and (34.0 ± 3.9)%, respectively (P < 0.05). Flow cytometry showed that after treatment with 100 and 1000 ng/ml doxorubicin for 48 h, the survival rates of SNK-6 cells were (69.9 ± 6.1)% and (31.1 ± 1.9)%, while treated in combination with 500 ng/ml TRAIL, the cell survival rates were (37.5 ± 6.4)% and (15.0 ± 1.8)%, respectively. The early apoptosis rate was (14.8 ± 0.6)% and (30.8 ± 1.5)%, significantly lower than that [(28.7 ± 0.6)% and (46.6 ± 2.8)%] after treatment in combination with TRAIL (P < 0.05). The expressions of TRAIL receptors and decoy receptors were increased when SNK-6 cells were treated with 100 ng/ml doxorubicin for 24 hours.</p><p><b>CONCLUSIONS</b>Doxorubicin can overcome to a certain extent the TRAIL resistance of SNK-6 cells and induce upregulation of TRAIL death receptors and decoy receptors on the surface of SNK-6 cells. However, a higher dose is needed.</p>

Identification of Novel Methylation Markers in Hepatocellular Carcinoma using a Methylation Array

Promoter CpG island hypermethylation has become recognized as an important mechanism for inactivating tumor suppressor genes or tumor-related genes in human cancers of various tissues. Gene inactivation in association with promoter CpG island hypermethylation has been reported to be four times more frequent than genetic changes in human colorectal cancers. Hepatocellular carcinoma is also one of the human cancer types in which aberrant promoter CpG island hypermethylation is frequently found. However, the number of genes identified to date as hypermethylated for hepatocellular carcinoma (HCC) is fewer than that for colorectal cancer or gastric cancer, which can be attributed to fewer attempts to perform genome-wide methylation profiling for HCC. In the present study, we used bead-array technology and coupled methylation-specific PCR to identify new genes showing cancer-specific methylation in HCC. Twenty-four new genes have been identified as hypermethylated at their promoter CpG island loci in a cancer-specific manner. Of these, TNFRSF10C, HOXA9, NPY, and IRF5 were frequently hypermethylated in hepatocellular carcinoma tissue samples and their methylation was found to be closely associated with inactivation of gene expression. Further study will be required to elucidate the clinicopathological implications of these newly found DNA methylation markers in hepatocellular carcinoma.

Screening and identification of differential expression genes related to stress fracture by cDNA microarray assay / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To evaluate the differentially expressed genes between the Stress fracture (SF) cases and controls.</p><p><b>METHODS</b>Total RNA was extracted and purified from peripheral blood sample of 3 SF cases and 3 controls who conducted a 1:1 matched case-control study, then used for Human Genome Array analysis. The hybridization data were analyzed using SAM software. Parts of these genes were analyzed and identified by real-time PCR.</p><p><b>RESULTS</b>Upregulated and downregulated genes were 22 and 1, respectively. Thus the highest ratio and most significant cytokine was tumor necrosis factor receptor superfamily, member 10c (TNFRSF10C). The result of real-time PCR shows that TNFRSF10C was over-expressed in 3 cases and low-expressed in 1 case.</p><p><b>CONCLUSION</b>Obvious difference exists in gene expression between SF cases and controls, showing there may be a lot of genes involving in the occurrence and development of SF. Meanwhile, the identification of the specific genes is helpful for biomechanics study, early diagnosis and screening of SF.</p>

Progress on targeting TRAIL's receptor as antitumor strategy / 药学学报

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.

Phenotypic and functional characteristics of endothelial cells derived from human liver cancer / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To analyze the phenotypic and functional characteristics of endothelial (T3A) cells derived from human hepatocellular cell carcinoma.</p><p><b>METHODS</b>Endothelial cells were isolated from human hepatocellular carcinoma specimens. The identification of T3A cells was performed by checking von Willebrand Factor (vWF), CD31, CD34 and Dil-Ac-LDL uptake. The cell surface fenestrations, a specific morphological feature of tumor derived EC, were investigated by scanning and transmission electron microscopy. The phenotypic characteristics of T3A cells were analyzed by fluorescence-activated cell sorter (FACS) and were further conformed by real-time PCR at transcription level. Furthermore, tumor necrosis factor alpha (TNFalpha)-induced cytotoxicity was evaluated by 3-(4, 5-dimethythiazolyl) -2, -diphenyl-2H-tetrazolium-bromide (MTT) assay; Matrix metalloproteinase secretion was detected by zymography; Angiogenic ability in vitro was analyzed by culturing T3A cells in three-dimensional Matrigel plug. Coagulant and fibrinolytic activities were detected by enzyme-linked immunosorbent assay (ELISA).</p><p><b>RESULTS</b>The isolated T3A cells exhibited classic "spindle-shape" morphology and monolayer growth and contact inhibition properties. Immunofluorescent staining showed that T3A cells expressed vWF, CD31, CD34, and uptake of Dil-Ac-LDL at a high level. The cell surface fenestrations were observed on T3A cells by scanning and transmission electron microscopy. By FACS and real-time PCR, T3A cells were found to express alphav3, alphavbeta5 and TNF receptor p75 at high levels, and TNF receptor p55 and ICAM-1 at low levels, as compared with those in human liver sinusoidal endothelial cells (LSEC). In response to TNFalpha, LSEC exhibited a dose-dependent cytotoxicity, while T3A cells were resistant. Gelatin zymography showed that MMP-2 activity was higher in T3A cells than that in LSEC. In a three-dimensional plug of Matrigel, T3A cells exhibited stronger angiogenic ability as compared with LSEC. In addition, T3A cells released more tissue factor (TF), tissue-type plasminogen activator (t-PA), plasminogen activator inhibitor (PAI-1) and urine plasminogen activator (u-PA) than LSEC in response to TNFalpha.</p><p><b>CONCLUSION</b>Tumor-derived endothelial cells are phenotypically and functionally different from those derived from normal liver tissue.</p>

X-ray irradiation enhances tumor necrosis factor receptor p55 expression in human colorectal cancer cells and inhibits the release of its soluble form in vitro / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effects of X ray on human colorectal cancer cells for their tumor necrosis factor receptor-p55 (TNFR-p55) expression and release of soluble soluble TNFR-p55 (sTNFR-p55) in vitro.</p><p><b>METHODS</b>The protein expression of TNFR-p55 in Lovo cells exposed to X-ray was detected using immunohistochemistry, and enzyme-linked immunosorbent assay was used to examine the levels of sTNFR-p55 in the supernatants of the cell culture. The cell apoptosis of the exposed cells was analyzed with flow cytometry, and the changes in cell morphology were observed microscopically.</p><p><b>RESULTS</b>X-ray exposure of cells resulted in a strong increase in TNFR-p55 expression of (P<0.01) and LoVo cell apoptosis (P<0.05). The levels of sTNFR-p55 in the supernatant of cells with X-ray exposure was significantly lowered in comparison with the levels before exposure (P<0.01). Optical microscopy showed that the exposed LoVo cells shrank and became spherical with cytoplasmic condensation and nuclear pyknosis.</p><p><b>CONCLUSION</b>X-ray exposure can induce LoVo cell apoptosis by increasing TNFR-p55 expression on the cell membrane and inhibiting the release of sTNFR-p55 in the supernatants.</p>

Biology and pathobiology of death receptors in liver / 生物医学工程学杂志

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.