Effect of gambogic acid on cell apoptosis and expressions of Bax, Bcl-2 and Caspase-3 in colorectal cancer cells with / 实用医学杂志

Objective To investiagate cell apoptosis and expressions of Bax,Bcl-2 andCaspase-3 in gambogic acid-treated colorectal cancer cells. Methods SW480/LOVO colorectal cancer cells were treated by gambogic acid. Cell Counting Kit-8 assay (CCK-8) was used to test cell proliferation. Microscopy was used to check the morphological changes. Immunofluorescence staining technique was used to detect cell apoptosis. Expressions of Bax,Bcl-2 and Caspase-3 protein were detected by Western blot assay. Results Gambogic acid inhibited the proliferation of SW480/LOVO in a dose and time-dependent manner. Gambogic acid could induce cell apoptosis. Gambogic acid increased expressions of Caspase-3 and Bax, increased the ratio of Bax/Bcl-2, and decreased Bcl-2 protein expression. Conclusion Gambogic acid can inhibit proliferation and induce apoptosis of SW480LOVO cells, with the mechanism of up-regulation of Bax/Bcl-2 and activation of Caspase-3.

Association of gankyrin protein expression in human colorectal cancer with postoperative prognosis / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To investigate the association of gankyrin protein expression in colorectal cancer (CRC) with its prognosis.</p><p><b>METHODS</b>Clinical data and resection samples of 100 colorectal cancer patients identified by pathology undergoing resection in our department from June 2008 to June 2009 were collected. The gankyrin expression in CRC tissues and matched adjacent noncancerous tissues collected during the operation of 100 CRC cases was detected by immunohistochemical staining and Western blotting. The associations of gankyrin expression level with overall survival, clinicopathologic features were analyzed by Chi square test, Cox regression analysis, Kaplan-Meier analysis and log rank test.</p><p><b>RESULTS</b>Immunohistochemical staining showed that the positive brown granules were mainly distributed in the cytoplasm, and nuclear immunostaining was observed in tissue samples of 29 cases, of whom 16 cases had distal metastasis [55.2% (16/29)]. The positive rate of gankyrin and the relative gray value of Western blotting in CRC tissues were 67% (67/100) and 0.69±0.23, respectively, which were significantly higher than those of 2 cm adjacent noncancerous tissues [6% (6/100) and 0.31±0.16] and 10 cm adjacent noncancerous tissues [1%(1/100) and 0.16±0.11] (all P<0.001). Patients with positive expression of gankyrin had worse survival than those with negative ones (41.8% vs. 72.7%, P=0.008). The gankyrin expression was associated to lymph node metastasis (P=0.005), tumor stage (P=0.001) and distal metastasis (P=0.002). Cox regression analysis showed that distal metastasis (P=0.004) and high expression of gankyrin (P=0.038) were independent risk factors for poor prognosis of patients with CRC.</p><p><b>CONCLUSION</b>Up-regulated expression of gankyrin is related to invasion and metastasis of human CRC, and gankyrin may be valuable in predicting prognosis.</p>

Epstein-Barr virus encoded latent membrane protein 1 induces TRAF1 expression to promote anti-apoptosis activity via NF-kappaB signaling pathway in nasopharyngeal carcinoma / 中华医学杂志(英文版)

<p><b>OBJECTIVES</b>To identify whether Epstein-Barr virus (EBV) encoded latent membrane protein 1 (LMP1) can induce tumor necrosis factor receptor-associated factor 1 (TRAF1) expression and promote its anti-apoptosis activity via the NF-kappaB signaling pathway, and assess that LMP1 suppresses apoptosis in nasopharyngeal carcinoma (NPC).</p><p><b>METHODS</b>A stable transfected cell line HNE2-LMP1 was established by introducing LMP1 cDNA into HNE2 cells. Transactivation of TRAF1 was determined by luciferase reporter assay, while expression of TRAF1 mRNA was detected by RT-PCR and expression of TRAF1 protein and caspase 3 by Western blot analysis. Apoptosis activity was observed through fluorescence staining.</p><p><b>RESULTS</b>LMP1 induced TRAF1 expression in NPC cells and caused a decrease in apoptosis. This induction could be blocked by antisense LMP1. Moreover, LMP1-mediated induction of a TRAF1 promoter-driven reporter gene was significantly impaired when the kappaB site kappaB1 or kappaB5 was disrupted, whereas mutation of kappaB3 had only a minor effect on LMP1 dependent up-regulation of the reporter gene.</p><p><b>CONCLUSION</b>LMP1 induces TRAF1 expression and promotes its anti-apoptosis activity via the NF-kappaB signaling pathway, which may be one of the mechanisms that LMP1 uses to suppress apoptosis in NPC cells.</p>

EB virus encoded latent membrane protein 1 modulates the phosphorylation of epidermal growth factor receptor in nasopharyngeal carcinoma cell line / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To elucidate the regulation of the phosphorylation of epidermal growth factor receptor (EGFR) by the EB virus encoded latent membrane protein 1 (LMP1) in nasopharyngeal carcinoma cell line.</p><p><b>METHODS</b>The levels of EGFR expression and phosphorylation in pTet-on LMP1 HNE2 cell, a nasopharyngeal carcinoma (NPC) cell line, in the dynamic expression of LMP1 induced by different concentrations of doxycycline (Dox) were observed. The EGFR dominant negative mutant and LMP1 antisense expression plasmid were transiently transfected into pTet-on LMP1 HNE2 cells by lipofectamine, and the changes in EGFR phosphorylation were observed by immunocoprecitation and Western blot. The changes in EGFR phosphorylation were observed after EGF treatment.</p><p><b>RESULTS</b>In pTet-on LMP1 HNE2 cells, Dox-induced LMP1 upregulated EGFR expression and phosphorylation in a dose-dependent manner. After EGFR dominant negative mutant was transfected into pTet-on LMP1 HNE2 cells, the increase of EGFR phosphorylation was inhibited completely. When LMP1 antisense expression plasmid was transfected into pTet-on LMP1 HNE2 cells, the levels of EGFR phosphorylation were also inhibited significantly. Meanwhile, after EGF had been added into pTet-on LMP1 HNE2 cells, increase of EGFR phosphorylation was induced, but it was completely blocked by EGFR dominant negative mutant and the introduction of LMP1 antisense.</p><p><b>CONCLUSION</b>EB virus encoded LMP1 not only induces the dose-dependent expression of EGFR, but also the dose-dependent phosphorylation of EGFR. The phosporylation of EGFR may play a vital role in the development of nasopharyngeal carcinoma.</p>

Matrix metalloproteinase 9 expression is induced by Epstein-Barr virus LMP1 via NF-kappa B or AP-1 signaling pathway in nasopharyngeal carcinoma cells / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To clarify if Epstein-Barr virus encoded LMP1 induces matrix metalloproteinase 9 expression via NF-kappa B or AP-1 signaling pathway, which gives evidence to the elucidation of the mechanism of LMP1- mediated carcinogenesis.</p><p><b>METHODS</b>To determine whether LMP1 or its mutants contribute to MMP9 production via NF-kappa B or AP-1 transcription factor, MMP9-chloramphenicol acetyl transferase (CAT), NF-kappa B mut 9-CAT, AP-1 mut MMP9-CAT were transfected into human nasopharyngeal carcinoma cells stably expressing LMP1 (HNE2-LMP1) or its mutants, [HNE2-LMP1 (1-185), HNE2-LMP1 (1-231), HNE2-LMP1 delta 187-351] by electroporation technic. The difference of MMP9 reporter activity among those cell lines was detected by CAT assay and expression of MMP9 was determined in nasopharyngeal carcinoma cells stably expressing LMP1 or its mutants by zymographic analysis. In the meantime, efforts were made to demonstrate if LMP1 regulates NF-kappa B or AP-1 activation using reporter gene analysis.</p><p><b>RESULTS</b>In contrast with vector-transfected cells, MMP9 CAT activity in HNE2-LMP1, HNE2-LMP1 (1-185), HNE2-LMP1(1-231), HNE2-LMP1 delta 187-351 increased 7.2, 1.3, 3.3, 4.0 times respectively. Zymographic analysis demonstrated that the 92 kDa MMP9 expression was induced in HNE2-LMP1, HNE2-LMP1(1-231) and HNE2-LMP1 delta 187-351 cells, whereas it was negative in HNE2-pSG5 and HNE2-LMP1 (1-185) cells. As compared to the HNE2 cells, NF-kappa B or AP-1 reporter activity in HNE2-LMP1 cells were increased 13.8, 8.4 fold respectively. Moreover, In contrast with MMP9 CAT-transfected cells, MMP9 CAT activity in NF-kappa B mut MMP9-CAT or AP-1 mut MMP9-CAT transfected HNE2-LMP1, HNE2-LMP1 (1-185), HNE2-LMP1(1-231) and HNE2-LMP1 delta 187-351 cells were significantly decreased by 18.1% or 16.3%, 35.0% or 33.3%, 29.1% or 26.1% from the original level. However, there was no difference in NF-kappa B mut MMP9-CAT or AP-1 mut MMP9-CAT transfected HNE2-pSG5, HNE2-LMP1 (1-185) cells.</p><p><b>CONCLUSION</b>In nasophargyngeal carcinoma, Epstein-Barr virus-encoded LMP1 induces MMP9 transcription and enzymatic activity via an NF-kappa B or AP-1 signaling pathway, which may contribute to invasiveness and metastasis.</p>

Interaction of Tumor Necrosis Factor Receptor-associated Factors with the Latent Membrane Protein 1 Is Essential for Activation of NF-κB / 生物化学与生物物理进展

The Epstein-Barr virus latent membrane protein 1 (LMP1) oncopro tein causes multiple cellular changes, including activation of the NF-κB trans cription factor. To elucidate its possible mechanism, the interaction between LM P1 and the tumor necrosis factor receptor associated factor (TRAF) molecules was detected by the immunoprecipitation-Western blotting assay. Results showed tha t LMP1 was co-precipitated with TRAF1,2,3 in the LMP1-HNE2 cell line. In the m eantime, κB reporter gene analysis revealed that over expression of TRAF1 or TR AF2 augmented LMP1-mediated NF-κB activation from LMP1, suprisingly, overexpr ession of either TRAF3 or an dominant negative TRAF3 inhibited the NF-κB activ ation, indicating that TRAF1 or TRAF2 is a positive modulator of LMP1-mediated NF-κB activation, whereas,TRAF3 is a negative modulator. Rather both CTAR1 (carboxy-terminal activating region 1) and CTAR2 domains of LMP1 can independently activate NF-κB by interacting with TRAF proteins. These data indicate that LMP1 interacts TRAF1,2,3 which are important for LMP1-mediated N F-κB activation, and further suggest that signaling from TRAFs may be involved in the progression to malignancy in cells of epithelial origin such as nasophar yngeal carcinoma (NPC).