Patients reporting persistent olfactory impairment after previously documented olfactory loss indicate a higher level of disability and lower quality of life than those with perceived resolution of olfactory compromise.

The transmembrane heparan sulfate proteoglycan syndecan-1 was identified from a human placenta cDNA library by the expression cloning method as a gene product that interacts with membrane type matrix metalloproteinase-1 (MT1- Syndecans are transmembrane heparan sulfate proteoglycans expressed on all adherent cells (1, 2) and have been proposed to play an important role in tissue morphogenesis by virtue of their ability to bind, via their covalently attached glycosaminoglycan chains, to a variety of extracellular adhesive molecules including fibronectin, thrombospondin, various collagens, and heparin-binding growth-associated molecules and growth factors such as basic fibroblast growth factor (3-8).MMPSince the expression of syndecans appears to be controlled during both development and the progression of tumor cells to the metastatic phenotype, it has been proposed that syndecans are important regulators of the migratory and invasive behaviors of both normal and transformed cells (9, 10). The syndecan family is composed of four closely related proteins (syndecan-1, -2, -3, and -4) encoded by four different genes. Syndecan-1 is abundant in normal epithelial cells and tissues, localizing to both basal and suprabasal cell layers (1). Disruption of syndecan-1 expression in cultured cells leads to an epithelial mesenchymal transformation, with associated changes in cell polarity and cell-cell adhesion and altered epithelium-specific gene expression (7, 11).The intact ectodomain of each syndecan is constitutively shed from cultured cells (12, 13) as part of normal cell surface heparan sulfate proteoglycan turnover (14). Ectodomain shedding appears to contribute to diverse pathophysiological events such as host defense, wound healing, arthritis, and Alzheimer's disease, but how shedding is regulated remains largely unknown (15-17).Matrix metalloproteinases (MMPs) 1 are a family of Zn 2ϩ -dependent enzymes that are known to cleave extracellular matrix proteins in normal and pathological conditions (18 -20). To date, more than 20 mammalian MMPs have been identified by cDNA cloning, and they can be subgrouped into soluble type and membrane type MMPs (MT-MMPs) (20,21). MMPs are overexpressed in various human malignancies and have been thought to contribute to tumor invasion and metastasis by degrading extracellular matrix components (18,22). Thus, the level of MMP expression correlates with the invasiveness or malignancy of tumors (23,24). Particularly, MT1-MMP, MMP-2, MMP-7, and MMP-9 have been reported to be most closely associated with tumor invasion and metastasis. Whereas degradation of extracellular matrix is an important aspect of MMP biology, growing evidence has demonstrated specific processing/activation or degradation of cell surface receptors and ligands. Fas ligand (25), tumor necrosis factor-␣ (26), the ectodomain of the fibroblast growth factor receptor-1 (27), the heparin-binding epidermal growth factor (28), and interleukin-8 (29) were reported to be released or activated by MMPs. MMPs also cleave and inac...

. Moreover, LMP1 induces HIF-1 DNA binding activity and upregulates HRE and VEGF promoter transcriptional activity. Finally, LMP1 increases the appearance of VEGF protein in extracellular fluids; induction of VEGF is suppressed by PD98059 or catalase. These results suggest that LMP1 increases HIF-1 activity through induction of HIF-1␣ protein expression, which is controlled by p42/p44 MAPK activity and H 2 O 2 . The ability of EBV, and specifically its major oncoprotein, LMP1, to induce HIF-1␣ along with other invasiveness and angiogenic factors reported previously discloses additional oncogenic properties of this tumor virus.

Cyclooxygenase-2 (COX-2) is an inducible form of COX and is overexpressed in diverse tumors, raising the possibility of a role for COX-2 in carcinogenesis. In addition, COX-2 contributes to angiogenesis. The Epstein–Barr virus (EBV) oncoprotein, latent membrane protein 1 (LMP1), is detected in at least 70% of nasopharyngeal carcinoma (NPC) and all EBV-infected preinvasive nasopharyngeal lesions. We found that in specimens of LMP1-positive NPC, COX-2 is frequently expressed, whereas LMP1-negative NPC rarely express the enzyme. We next found that expression of LMP1 in EBV-negative nasopharyngeal epithelial cells induced COX-2 expression. Coexpression of IκBα(S32A/S36A), which is not phosphorylated and prevents NF-κB activation, with LMP1 showed that NF-κB is essential for induction of COX-2 by LMP1. We also demonstrate that NF-κB is involved in LMP1-induced cox-2 promoter activity with the use of reporter assays. Two major regions of LMP1, designated CTAR1 and CTAR2, are signal-transducing domains of LMP1. Constructs expressing either CTAR1 or CTAR2 induce COX-2 but to a lesser extent than wild-type LMP1, consistent with the ability of both regions to activate NF-κB. Furthermore, we demonstrate that LMP1-induced COX-2 is functional because LMP1 increased production of prostaglandin E 2 in a COX-2-dependent manner. Finally, we demonstrate that LMP1 increased production of vascular endothelial growth factor (VEGF). Treatment of LMP1-expressing cells with the COX-2-specific inhibitor (NS-398) dramatically decreased production of VEGF, suggesting that LMP1-induced VEGF production is mediated, at least in part, by COX-2. These results suggest that COX-2 induction by LMP1 may play a role in angiogenesis in NPC.

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