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Introduction: Nasopharyngeal carcinoma, an epithelial-derived malignant tumor which because of its anatomical location and atypical early symptoms, when diagnosed invasion and metastasis often have occurred. This requires a better understanding of the development mechanism, identifying diagnostic markers, and developing new treatment strategies. Objective: To study the relationship of LMP1 and Cripto-1 in nasopharyngeal carcinoma. Methods: The expression of LMP1 and Cripto-1 in specimens obtained from nasopharyngeal carcinoma patients (n = 42) and nasopharyngitis patients (n = 22) were examined. The expression of LMP1 and Cripto-1 in LMP1-negative and LMP1-positive (CNE1-LMP1) cells were also examined. Results: The expression of LMP1 and Cripto-1 was significantly higher in nasopharyngeal carcinoma than in nasopharyngitis (p

Exploring the re-emergence of embryonic signaling pathways may reveal important information for cancer biology. Nodal is a transforming growth factor-β (TGF-β)-related morphogen that plays a critical role during embryonic development. Nodal signaling is regulated by the Cripto-1 co-receptor and another TGF-β member, Lefty. Although these molecules are poorly detected in differentiated tissues, they have been found in different human cancers. Poor prognosis of glioblastomas justifies the search for novel signaling pathways that can be exploited as potential therapeutic targets. Because our intracranial glioblastoma rat xenograft model has revealed importance of gene ontology categories related to development and differentiation, we hypothesized that increased activity of Nodal signaling could be found in glioblastomas. We examined the gene expressions of Nodal, Cripto-1, and Lefty in microarrays of invasive and angiogenic xenograft samples developed from four patients with glioblastoma. Protein expression was evaluated by immunohistochemistry in 199 primary glioblastomas, and expression levels were analyzed for detection of correlations with available clinical information. Gene expression ofNodal, Lefty, and Cripto-1 was detected in the glioblastoma xenografts. Most patient samples showed significant levels of Cripto-1 detected by immunohistochemistry, whereas only weak to moderate levels were detected for Nodal and Lefty. Most importantly, the higher Cripto-1 scores were associated with shorter survival in a subset of younger patients. These findings suggest for the first time that Cripto-1, an important molecule in developmental biology, may represent a novel prognostic marker and therapeutic target in categories of younger patients with glioblastoma. publishedVersion

Publisher Summary This chapter examines the signaling pathways in the normal and neoplastic breast. The epidermal growth factor (EGF) family members that bind to EGFR are EGF, transforming growth factor α (TGFα), amphiregulin (AR, a heparin-binding factor), heparin-binding EGF (HbEGF), epiregulin, and β-cellulin. Cripto (CR-1) is an EGF family member that plays an important role in embryogenesis and mammary gland development. CR-1 is overexpressed in several human tumors. However, CR-1 binds to a type I serine/threonine kinase receptor for activin (ALK4), which is expressed on the cell surface of mammary epithelial cells, rather than binding to EGFR or one of the other ErbB receptors. ErbB receptors undergo homo- or heterodimerization following ligand binding. After ligand binding, EGFR/ErbB1/HER-1 undergoes either endocytosis and degradation by both proteasomal and lysosomal pathways, or the receptor is recycled to plasma membrane. ErbB2/HER-2 is considered to be endocytosis-impaired, and is the most stable protein among ErbBs in the plasma membrane. Ductal growth in the mammary epithelium is defective when ErbB2 is disrupted in the mammary gland, implying a prominent role for ErbB2 in mammary ductal growth. ErbB2 plays a significant role in ductal morphogenesis. While kinase-dead, ErbB3/HER-3 frequently forms a high-affinity co-receptor for heregulin by heterodimerization with ErbB2/HER-2. ErbB3/HER-3 possesses several docking sites for PI3K, and can initiate PI3K/Akt signaling when transactivated by ErbB2/HER-2. EGF can act as an oncogene-like molecule when transfected and overexpressed in immortalized rodent fibroblasts. Forced overexpression of EGFR in the mammary gland, under the control of the MMTV or β-lactoglobulin (BLG) promoters, results in abnormal mammary gland development and the production of epithelial hyperplasias.

Glucose-regulated protein 78 (GRP78) is a potential receptor for targeting therapy in cancer and chronic vascular disease due to its overexpression at the cell surface in tumor cells and in atherosclerotic lesions. Presence of the GRP78 autoantibody in cancer patient sera is generally associated with poor prognosis since it signals a prosurvival mechanism in response to cellular stress. Association of GRP78 with various binding partners involves coordination of multiple signaling pathways that result in either cell survival or cell death. Binding of activated alpha2-macroglobulin to cell-surface GRP78 activates Akt to suppress apoptotic pathways through multiple downstream effectors, and concomitantly upregulates NF-kappaBeta and induces the unfolded protein response (UPR) so that cell proliferation prevails. Interaction of GRP78 with cell-surface T-cadherin promotes endothelial cell survival. Association of oncogenic Cripto with GRP78 nullifies TGF-beta superfamily-dependent signaling through Smad2/3 to promote cell proliferation. In contrast, association of GRP78 with the plasminogen kringle 5 domain or extracellular Par-4 promotes apoptosis. Interaction of GRP78 with microplasminogen induces the UPR while association with tissue factor inhibits procoagulant activity. The diverse and multiple binding proteins of GRP78 and their equally diverse functional outcomes reflect the regulatory cellular functions that GRP78 orchestrates. Several GRP78 targeting peptides have been isolated from different tumors and they show remarkable tumor specificity. Conjugation of GRP78-targeting peptides to an apoptosis-inducing peptide suppresses tumor growth in tumor xenografts, thereby demonstrating that GRP78 is a viable target by which clinical cancer therapies can be successfully developed as well as its potential utility in treating vascular disease.

Human Cripto-1 (CR-1), a member of the epidermal growth factor (EGF)-CFC family, has been implicated in embryogenesis and in carcinogenesis. During early vertebrate development, CR-1 functions as a co-receptor for Nodal, a transforming growth factor beta (TGFbeta) family member and is essential for mesoderm and endoderm formation and anterior-posterior and left-right axis establishment. In adult tissues, CR-1 is expressed at a low level in all stages of mammary gland development and expression increases during pregnancy and lactation. Overexpression of CR-1 in mouse mammary epithelial cells leads to their transformation in vitro and, when injected into mammary glands, produces ductal hyperplasias. CR-1 can also enhance migration, invasion, branching morphogenesis and epithelial to mesenchymal transition (EMT) of several mouse mammary epithelial cell lines. Furthermore, transgenic mouse studies have shown that overexpression of a human CR-1 transgene in the mammary gland under the transcriptional control of the mouse mammary tumor virus (MMTV) promoter results in mammary hyperplasias and papillary adenocarcinomas. Finally, CR-1 is expressed at high levels in approximately 50 to 80% of different types of human carcinomas, including breast, cervix, colon, stomach, pancreas, lung, ovary, and testis. In conclusion, EGF-CFC proteins play dual roles as embryonic pattern formation genes and as oncogenes. While during embryogenesis EGF-CFC proteins perform specific and regulatory functions related to cell and tissue patterning, inappropriate expression of these molecules in adult tissues can lead to cellular proliferation and transformation and therefore may be important in the etiology and/or progression of cancer.

The relation between the role of the organizer at the gastrula stage and the activity of earlier signals in the specification, maintenance, and regionalization of the developing brain anlage is still controversial. Mouse embryos homozygous for null mutation in the cripto gene die at about 9.0 days postcoitum (d.p.c.) and fail to gastrulate and to form the node (the primary organizer). Here, we study the presence and the distribution of anterior neural plate molecular domains in cripto null mutants. We demonstrate that, in cripto−/− embryos, the main prosencephalic and mesencephalic regions are present and that they assume the correct topological organization. The identity of the anterior neural domains is maintained in mutant embryos at 8.5 d.p.c., as well as in mutant explants dissected at 8.5 d.p.c. and cultured in vitro for 24 h. Our data imply the existence of a stable neural regionalization of anterior character inside the cripto−/− embryos, despite the failure in both the gastrulation process and node formation. These results suggest that, in mouse embryos, the specification of the anterior neural identities can be maintained without an absolute requirement for the embryonic mesoderm and the node., This work was supported by grants from the BioGem S.C.A.R.1. Associazione Italiana Ricerca sul Cancro (AIRC) and CNR, PS Murst (to G.P.), and by EU grants QLG2-CT-1999-00793, QLRT-1999-31556, 1999-31625, 2000-02310, and Spanish MCT grant DGI BFI2002-02979, DIGESIC-MEC PM98-0056, FEDER-1FD97-2090, and also from the Generalitat Valenciana CTDIA/2002/91 (to S.M. and D.E.). BioGem s.c a r.l. provides R.I. salary. G.L. has been awarded an EMBO short term fellowship.

A fundamental challenge in biology is to explain how progenitor cells in developing tissues acquire distinct fates according to their position. In vertebrates, the positional information that specifies the germ layers and the primary body axes is mediated by Nodal. Nodal meets the criteria of a morphogen since it can diffuse through tissues and signal far away from its source to directly specify multiple cell fates in a dosage-dependent manner. To consider the relationship between trafficking and graded Nodal signaling, this review summarizes recent findings how the spreading of Nodal activity is regulated by factors that promote long range signaling during left-right axis formation, and by structural features that affect Nodal protein stability and endosomal sorting.