Home About us Contact
|
Home About us Contact | ||
|
|
||
LMP1 Expression (lmp1 + expression)
Selected AbstractsMolecular characterization of epstein-barr virus and oncoprotein expression in nasopharyngeal carcinoma in KoreaHEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 7 2004Yoon Kyung Jeon MD Abstract Background. We evaluated the characteristics of nasopharyngeal carcinoma in Korea, including its clinical, pathologic, and molecular features, especially emphasizing on the EBV strains involved, latent membrane protein 1 (LMP1) expression, and the alterations of matrix metalloproteinase 9 (MMP9) and E-cadherin expression. Methods. The presence of EBV was evaluated by EBER in situ hybridization, and the expression of LMP1, MMP9, and E-cadherin by immunohistochemistry. The characterization of EBV type and LMP1 variant was performed by PCR. Results. EBER was detected in 55 of 57 cases (96%) of nonkeratinizing carcinoma (NKC) and undifferentiated carcinoma, but in only four of nine cases (44%) of squamous cell carcinoma (SCC). EBER positivity was much higher in the group with nodal metastases (p = .003). The predominant strain of EBV infection was type A (81%) and a 30-bp deletion LMP1 variant (77%). All EBER-positive SCCs were infected with EBV type A. LMP1 expression was detected in 36 of 59 (61%) patients with latent EBV infection and MMP9 in 41 of these 59 (69%). LMP1 positivity was much higher among the patients aged 50 years and younger. MMP9 expression was associated with LMP1 expression (p = .008), and nodal and distant metastasis (p = .019, p = .045). Loss of E-cadherin expression was correlated with MMP9 and nodal metastasis. The survival rate was much lower in patients with a higher TNM classification, stage, and a histology of SCC. EBER positivity was associated with a better prognosis in the Kaplan-Meier test, but had no prognostic value by Cox regression analysis. Loss of E-cadherin expression and nodal metastasis were also correlated with local recurrence and distant metastasis. Conclusion. EBV type and LMP1 variant had no significant influence on the clinicopathologic properties of tumor. However, there was a tendency toward a better survival in the EBV type B group. Histology and clinical staging were the two most important prognostic factors. © 2004 Wiley Periodicals, Inc. Head Neck26: 573,583, 2004 [source] Expression of RANTES and MCP-1 in epithelial cells is regulated via LMP1 and CD40INTERNATIONAL JOURNAL OF CANCER, Issue 12 2007Maike Buettner Abstract Epstein-Barr virus (EBV)-associated undifferentiated nasopharyngeal carcinoma (NPC) is characterized by a prominent nonneoplastic lymphoid stroma. The functional role of these inflammatory cells and the mechanism of their recruitment are not fully understood. In B-cells, the EBV-encoded latent membrane protein 1 (LMP1) can induce the expression of chemokines in an NF-,B dependent manner. We now show that LMP1 can induce the expression of RANTES and MCP-1 in an epithelial cell line, and that this effect is partially reversible by an inhibitor of NF-,B. Since tumor cells of virtually all NPCs show CD40 expression while many cases are LMP1-negative at the protein level, we also investigated the effect of CD40 signaling and demonstrate that CD40 stimulation can transiently induce RANTES and MCP-1 expression in LMP1-negative epithelial cells. In in situ hybridization only rare tumor cells showed expression of these chemokines unrelated to LMP1 expression, a pattern consistent with transient induction through CD40 signaling. Since RANTES and MCP-1 were also detected in the neoplastic cells of oral squamous cell carcinomas lacking a lymphoid stroma it remains uncertain to what extent these CC chemokines contribute to the attraction of inflammatory cells into the NPC microenvironment. © 2007 Wiley-Liss, Inc. [source] TRAF interactions with raft-like buoyant complexes, better than TRAF rates of degradation, differentiate signaling by CD40 and EBV latent membrane protein 1INTERNATIONAL JOURNAL OF CANCER, Issue 2 2005Hector Ardila-Osorio Abstract The CD40 receptor and the Epstein-Barr virus oncoprotein LMP1 are both members of the TNF-receptor family and share several signaling mediators, including TRAF2 and TRAF3. Depending on the cell lineage and stage of maturation, LMP1 and CD40 can have synergistic, antagonist or unrelated effects. Previous publications have suggested that both TRAF2 and TRAF3 move into lipid rafts upon LMP1 expression or CD40 activation, whereas their proteolysis is only enhanced by CD40. However CD40-induced proteolysis of TRAF2 has only been reported in murine cells, and there are conflicting data regarding translocation of TRAF2 into lipid rafts. We therefore investigated TRAF2 and TRAF3 modifications induced by CD40 and LMP1 signaling in a panel of human cell lines of lymphoid and epithelial origins. Upon CD40 stimulation, a marked redistribution of TRAF2 into the buoyant raft fraction was observed in all cell lines and was often associated with a similar redistribution of TRAF3. In contrast, only TRAF3 was redistributed into the raft fraction upon LMP1 expression. Moreover parallel changes in subcellular distribution of TRAF2 and TRAF3 were recorded by electron microscopy. A significant decrease in TRAF2 and TRAF3 concentrations triggered by CD40 ligation was observed in only 1 cell line and there was no evidence that this decrease was required for the negative feed-back on JNK activation. TRAF2 redistribution into raft-like complexes thus appears as the most significant event distinctive of CD40 and LMP1 signaling. On the other hand, the parallel influence of CD40 and LMP1 on TRAF3 redistribution is consistent with functional similarities between the CD40-TRAF3 and LMP1-TRAF3 axes. [source] Expression of Epstein-Barr virus-encoded LMP1 and hTERT extends the life span and immortalizes primary cultures of nasopharyngeal epithelial cells,JOURNAL OF MEDICAL VIROLOGY, Issue 10 2010Yim-Ling Yip Abstract Cell immortalization is regarded as an early and pre-requisite step in tumor development. Defining the specific genetic events involved in cell immortalization may provide insights into the early events of carcinogenesis. Nasopharyngeal carcinoma is common among the Southern Chinese population. Epstein-Barr virus (EBV) infection is associated closely with nasopharyngeal carcinoma. The involvement of LMP1 (an EBV-encoded oncogene) has been implicated in the pathogenesis of nasopharyngeal carcinoma. In this study, LMP1 expression, in combination with ectopic expression of hTERT (catalytic unit of human telomerase), was shown to extend the life span of primary cultures of nasopharyngeal epithelial cells and facilitate the immortalization of one of the cell lines (NP446). This is the first report on the successful immortalization of nasopharyngeal epithelial cells involving LMP1. The events associated with the immortalization of nasopharyngeal epithelial cells by LMP1/hTERT were characterized. Expression of c-Myc, Bmi-1, and Id-1 were upregulated at an early stage of immortalization. At a later stage of immortalization, downregulation of p21 and p16 expression were observed. Upregulation of EGFR expression and activation of MAPK signaling pathway were observed in LMP1/hTERT -immortalized nasopharyngeal epithelial cells. The LMP1/hTERT -immortalized NP446 cells were non-tumorigenic in immunosuppressed nude mice and retained anchorage-dependent growth, suggesting that additional events are required for tumorigenic transformation. The ability of the EBV-encoded LMP1, in the presence of hTERT expression, to extend the life span and immortalize primary cultures of nasopharyngeal epithelial cells supports the involvement of EBV infection and its viral products in the early stage of pathogenesis of nasopharyngeal carcinoma. J. Med. Virol. 82:1711,1723, 2010. © 2010 Wiley-Liss, Inc. [source] | ||||||||||