Reduced expression of neural cell adhesion molecule induces metastatic dissemination of pancreatic beta tumor cells

CD56 Expression in Papillary Thyroid Carcinoma Is Highly Dependent on the Histologic Subtype: A Potential Diagnostic Pitfall

Loss of CD56 expression has been regarded as a diagnostic marker of papillary thyroid carcinoma (PTC). However, certain variants of PTC can aberrantly express CD56. Using a digital image analysis tool, we evaluated H-scores of CD56 immunostaining in 216 thyroid tumors. The H-score of the CD56 of all PTCs was lower than that of noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) (P<0.001). The H-scores of CD56 were lower in classic PTC, the infiltrative follicular variant, and the diffuse sclerosing variant than in other PTC variants (P<0.001), whereas the H-scores were higher in tall cell variant, Warthin-like variant, and cribriform-morular variant than in classic PTC (P<0.001). The optimal cutoff value of H-scores for the CD56 expression was 180 for differentiating the NIFTP from the follicular adenoma and 30 for the differential diagnosis of NIFTP and infiltrative follicular variant PTC. CD56 expression is predominantly lost in classic and infiltrative follicular variants of PTCs and more preserved in the other histologic subtypes of PTC and NIFTP. CD56 is particularly useful for differentiating PTC from follicular-pattern thyroid neoplasms, but the aberrant expression in uncommon variants of PTC could be a diagnostic pitfall.

Withania somnifera (L.) Dunal: A potential therapeutic adjuvant in cancer

ETHNOPHARMACOLOGICAL RELEVANCE

Withania somnifera (L.) Dunal (WS) is one of the moststudied Rasayana botanicals used in Ayurveda practice for its immunomodulatory, anti-aging, adaptogenic, and rejuvenating effects. The botanical is being used for various clinical indications, including cancer. Several studies exploring molecular mechanisms of WS suggest its possible role in improving clinical outcomes in cancer management. Therefore, research on WS may offer new insights in rational development of therapeutic adjuvants for cancer.

AIM OF THIS REVIEW

The review aims at providing a detailed analysis of in silico, in vitro, in vivo, and clinical studies related to WS and cancer. It suggests possible role of WS in regulating molecular mechanisms associated with carcinogenesis. The review discusses potential of WS in cancer management in terms of cancer prevention, anti-cancer activity, and enhancing efficacy of cancer therapeutics.

MATERIAL AND METHODS

The present narrative review offers a critical analysis of published literature on WS studies in cancer. The reported studies were analysed in the context of pathophysiology of cancer, commonly referred as 'cancer hallmarks'. The review attempts to bridge Ayurveda knowledge with biological insights into molecular mechanisms of cancer.

RESULTS

Critical analysisof the published literature suggests an anti-cancer potential of WS with a key role in cancer prevention. The possible mechanisms for these effects are associated with the modulation of apoptotic, proliferative, and metastatic markers in cancer. WS can attenuate inflammatory responses and enzymes involved in invasion and metastatic progression of cancer.The properties of WS are likely to be mediated through withanolides, which may activate tumor suppressor proteins to restrict proliferation of cancer cells. Withanolides also regulate the genomic instability, and energy metabolism of cancer cells. The reported studies indicate the need for deeper understanding of molecular mechanisms of WS in inhibiting angiogenesis and promoting immunosurveillance. Additionally, WS can augment efficacy and safety of cancer therapeutics.

CONCLUSION

The experimentally-supported evidence of immunomodulatory, anti-cancer, adaptogenic, and regenerative attributes of WS suggest its therapeutic adjuvant potential in cancer management. The adjuvant properties of withanolides can modulate multidrug resistance and reverse chemotherapy-induced myelosuppression. These mechanisms need to be further explored in systematically designed translational and clinical studies that will pave the way for integration of WS as a therapeutic adjuvant in cancer management.

Transcription Factors Contribute to Differential Expression in Cellular Pathways in Lung Adenocarcinoma and Lung Squamous Cell Carcinoma

Lung cancers are broadly classified into small cell lung cancers and non-small cell lung cancers (NSCLC). Lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC) are two common subtypes of NSCLC, and despite the fact that both occur in lung tissues, these two subtypes show a number of different pathological characteristics. To investigate the differences and seek potential therapy targets, we used bioinformatics methods to analyze RNA-Seq data from different aspects. The previous studies and comparative pathway enrichment analysis on publicly available data showed that expressed or inhibited genes are different in two cancer subtypes through important pathways. Some of these genes could not only affect cell function through expression, but also could regulate other genes' expression by binding to a specific DNA sequence. This kind of genes is called transcription factor (TF) or sequence-specific DNA-binding factor. Transcription factors play important roles in controlling gene expression in carcinoma pathways. Our results revealed transcription factors that may cause differential expression of genes in cellular pathways of LUAD and LUSC, which provide new clues for study and treatment. Once such TF is NFE2l2 which may regulate genes in the Wnt signaling pathway, and the MAPK signaling pathway, thus leading to an increase the cell growth, cell division, and gene transcription. Another TF-XBP1 has high correlation with genes related to cell adhesion molecules and cytokine-cytokine receptor interaction pathways that may further affect the immune system. Moreover, the two TF and high correlated genes also show similar patterns in an independent GEO data set.

Antibodies against cell adhesion molecules and neural structures in paraneoplastic neuropathies

Objective

Paraneoplastic neurological syndromes (PNS) are rare neurological disorders in which ectopic expression of neural antigens by a tumor results in an autoimmune attack against the nervous system. Onconeural antibodies not only guide PNS diagnosis but may also help detecting underlying malignancies. Our project aims to uncover new potential antibodies in paraneoplastic neuropathies (PN).

Methods

Thirty‐four patients fulfilling diagnostic criteria of possible (n = 9; 26.5%) and definite (n = 25; 73.5%) PN without onconeural antibodies and 28 healthy controls were included in our study. Sera were tested for known antibodies against neural cell adhesion molecules and screened for novel IgG and IgM reactivities against nerve components: dorsal root ganglia (DRG) neurons, motor neurons, and Schwann cells. Patients showing autoantibodies against any of these cell types were used for immunoprecipitation (IP) studies.

Results

Overall, 9 (26.5%) patients showed significant reactivity against DRG neurons, motor neurons, or Schwann cells, whereas 5 (17.9%) healthy controls only showed moderate reactivity. Compared with control sera, serum samples from patients with paraneoplastic sensory‐motor neuropathies had a higher frequency of IgM antibodies against Schwann cells (0% vs. 40%; P = 0.0028). No novel antigens were identified from our IP experiments. Antibodies against the neural adhesion molecules CNTN1, NF155, NF140, NF186, NCAM1, L1CAM, and the CNTN1/CASPR1 complex were not detected in patients with PN. One (2.9%) patient with CIDP and thymoma had CASPR2 antibodies.

Interpretation

Almost 30% of patients with PN harbor antibodies targeting neural structures, suggesting that novel neoplasm‐associated antigens remain to be discovered.

GFRα1 Regulates Purkinje Cell Migration by Counteracting NCAM Function

During embryonic development of the cerebellum, Purkinje cells (PCs) migrate away from the ventricular zone to form the PC plate. The mechanisms that regulate PC migration are incompletely understood. Here, we report that the neurotrophic receptor GFRα1 is transiently expressed in developing PCs and loss of GFRα1 delays PC migration. Neither GDNF nor RET, the canonical GFRα1 ligand and co-receptor, respectively, contribute to this process. Instead, we found that the neural cell adhesion molecule NCAM is co-expressed and directly interacts with GFRα1 in embryonic PCs. Genetic reduction of NCAM expression enhances wild-type PC migration and restores migration in Gfra1 mutants, indicating that NCAM restricts PC migration in the embryonic cerebellum. In vitro experiments indicated that GFRα1 can function both in cis and trans to counteract NCAM and promote PC migration. Collectively, our studies show that GFRα1 contributes to PC migration by limiting NCAM function.

Genome-scale analysis to identify prognostic markers in patients with early-stage pancreatic ductal adenocarcinoma after pancreaticoduodenectomy

BACKGROUND

Molecular analysis is a promising source of clinically useful prognostic biomarkers. The aim of this investigation was to identify prognostic biomarkers for patients with early-stage pancreatic ductal adenocarcinoma (PDAC) after pancreaticoduodenectomy.

METHODS

An RNA sequencing dataset of PDAC was obtained from The Cancer Genome Atlas. Survival analysis and weighted gene co-expression network analysis were used to investigate the prognostic markers of early-stage PDAC after pancreaticoduodenectomy.

RESULTS

Using whole genome expression level screening, we identified 1,238 markers that were related to the prognosis of PDAC after pancreaticoduodenectomy, and identified 9 hub genes (ARHGAP30, HCLS1, CD96, FAM78A, ARHGAP15, SLA2, CD247, GVINP1, and IL16) using the weighted gene co-expression network analysis approach. We also constructed a signature comprising the 9 hub genes and weighted by the regression coefficient derived from a multivariate Cox proportional hazards regression model to divide patients into a high-risk group, with increased risk of death, and a low-risk group, with significantly improved overall survival (adjusted P=0.026, adjusted HR =0.513, 95% CI =0.285-0.924). The prognostic signature of the 9 genes demonstrated good performance for predicting 1-year overall survival (area under the respective receiver operating characteristic curves =0.641).

CONCLUSION

Our results have provided a new prospect for prognostic biomarkers of PDAC after pancreaticoduodenectomy, and may have a value in clinical application.

Intrabodies against the Polysialyltransferases ST8SiaII and ST8SiaIV inhibit Polysialylation of NCAM in rhabdomyosarcoma tumor cells

Background

Polysialic acid (polySia) is a carbohydrate modification of the neural cell adhesion molecule (NCAM), which is implicated in neural differentiation and plays an important role in tumor development and metastasis. Polysialylation of NCAM is mediated by two Golgi-resident polysialyltransferases (polyST) ST8SiaII and ST8SiaIV. Intracellular antibodies (intrabodies; IB) expressed inside the ER and retaining proteins passing the ER such as cell surface receptors or secretory proteins provide an efficient means of protein knockdown. To inhibit the function of ST8SiaII and ST8SiaIV specific ER IBs were generated starting from two corresponding hybridoma clones. Both IBs αST8SiaII-IB and αST8SiaIV-IB were constructed in the scFv format and their functions characterized in vitro and in vivo.

Results

IBs directed against the polySTs prevented the translocation of the enzymes from the ER to the Golgi-apparatus. Co-immunoprecipitation of ST8SiaII and ST8SiaIV with the corresponding IBs confirmed the intracellular interaction with their cognate antigens. In CHO cells overexpressing ST8SiaII and ST8SiaIV, respectively, the transfection with αST8SiaII-IB or αST8SiaIV-IB inhibited significantly the cell surface expression of polysialylated NCAM. Furthermore stable expression of ST8SiaII-IB, ST8SiaIV-IB and luciferase in the rhabdomyosarcoma cell line TE671 reduced cell surface expression of polySia and delayed tumor growth if cells were xenografted into C57BL/6 J RAG-2 mice.

Conclusion

Data obtained strongly indicate that αST8SiaII-IB and αST8SiaIV-IB are promising experimental tools to analyze the individual role of the two enzymes during brain development and during migration and proliferation of tumor cells.

Electronic supplementary material

The online version of this article (doi:10.1186/s12896-017-0360-7) contains supplementary material, which is available to authorized users.

Loss of Cell Adhesion Increases Tumorigenic Potential of Polarity Deficient Scribble Mutant Cells

Epithelial polarity genes are important for maintaining tissue architecture, and regulating growth. The Drosophila neoplastic tumor suppressor gene scribble (scrib) belongs to the basolateral polarity complex. Loss of scrib results in disruption of its growth regulatory functions, and downregulation or mislocalization of Scrib is correlated to tumor growth. Somatic scribble mutant cells (scrib^-) surrounded by wild-type cells undergo apoptosis, which can be prevented by introduction of secondary mutations that provide a growth advantage. Using genetic tools in Drosophila, we analyzed the phenotypic effects of loss of scrib in different growth promoting backgrounds. We investigated if a central mechanism that regulates cell adhesion governs the growth and invasive potential of scrib mutant cells. Here we show that increased proliferation, and survival abilities of scrib^- cells in different genetic backgrounds affect their differentiation, and intercellular adhesion. Further, loss of scrib is sufficient to cause reduced cell survival, activation of the JNK pathway and a mild reduction of cell adhesion. Our data show that for scrib cells to induce aggressive tumor growth characterized by loss of differentiation, cell adhesion, increased proliferation and invasion, cooperative interactions that derail signaling pathways play an essential role in the mechanisms leading to tumorigenesis. Thus, our study provides new insights on the effects of loss of scrib and the modification of these effects via cooperative interactions that enhance the overall tumorigenic potential of scrib deficient cells.

Methods to Study Metastasis in Genetically Modified Mice

Metastasis is often modeled by xenotransplantation of cell lines in immunodeficient mice. A wealth of information about tumor cell behavior in the new environment is obtained from these efforts. Yet by design, this approach is "tumor-centric," as it focuses on cell-autonomous determinants of human tumor dissemination in mouse tissues, in effect using the animal body as a sophisticated "Petri dish" providing nutrients and support for tumor growth. Transgenic or gene knockout mouse models of cancer allow the study of tumor spread as a systemic disease and offer a complimentary approach for studying the natural history of cancer. This introduction is aimed at describing the overall methodological approach to studying metastasis in genetically modified mice, with a particular focus on using animals with regulated expression of potent human oncogenes in the breast.

Coexistence of neuroblastoma and ganglioneuroma in a girl with a hemizygous deletion of chromosome 11q14.1-23.3

Constitutional 11q interstitial deletion syndrome presents with congenital anomalies including microcephaly with craniostenosis, minor dysmorphic features, vitreoretinopathy, and renal anomalies. This syndrome is occasionally associated with neuroblastoma (NB) as a life-threatening complication, which is important for clinical care. Although the corresponding locus to NB has been predicted to exist in 11q22-23 by previous deletion studies related to NB, the causative haploinsufficient genes have not yet been identified. We herein reported for the first time the simultaneous coexistence of adrenal NB and abdominal prevertebral ganglioneuroma in a 6-year-old girl with a constitutional hemizygous 11q14.1-23.3 deletion. Of the 11 haploinsufficient genes predicted with an in silico database, we focused on NCAM1 and CADM1 as the genes accountable for NB and ganglioneuroma. The deletion range, especially the 11q22.3 involvement, needs to be determined in 11q deletion cases in order to predict susceptibility to peripheral nerve tumors involving NB and ganglioneuroma.

MiR-30a-5p is induced by Wnt/β-catenin pathway and promotes glioma cell invasion by repressing NCAM

Wnt/β-catenin signaling pathway is frequently dysregulated in human tumors and plays a critical role in tumorigenesis; however, the roles of microRNAs in mediating Wnt/β-catenin pathway are not well understood. Herein, we show that miR-30a-5p is activated by Wnt/β-catenin pathway through direct binding of β-catenin/TCF4 to two sites in the promoter region of miR-30a-5p. We also found that miR-30a-5p represses neural cell adhesion molecule (NCAM) expression by directly targeting two sites in the 3' untranslated region (3'-UTR) of NCAM mRNA. Moreover, Wnt/β-catenin pathway represses NCAM expression in glioma cells, which depends on miR-30a-5p. Finally, we found that miR-30a-5p promotes glioma cell growth invasion by repressing NCAM. Our findings demonstrate a novel Wnt/β-catenin-miR-30a-5p-NCAM regulatory axis which plays important roles in controlling glioma cell invasion and tumorigenesis.

Inhibition of Neurosphere Formation in Neural Stem/Progenitor Cells by Acrylamide

Previous studies showed that transplantation of cultured neural stem/progenitor cells (NSPCs) could improve functional recovery for various neurological diseases. This study aims to develop a stem cell-based model for predictive toxicology of development in the neurological system after acrylamide exposure. Treatment of mouse (KT98/F1B-GFP) and human (U-1240 MG/F1B-GFP) NSPCs with 0.5 mM acrylamide resulted in the inhibition of neurosphere formation (definition of self-renewal ability in NSPCs), but not inhibition of cell proliferation. Apoptosis and differentiation of KT98 (a precursor of KT98/F1B-GFP) and KT98/F1B-GFP are not observed in acrylamide-treated neurospheres. Analysis of secondary neurosphere formation and differentiation of neurons and glia illustrated that acrylamide-treated KT98 and KT98/F1B-GFP neurospheres retain the NSPC properties, such as self-renewal and differentiation capacity. Correlation of acrylamide-inhibited neurosphere formation with cell-cell adhesion was observed in mouse NSPCs by live cell image analysis and the presence of acrylamide. Protein expression levels of cell adhesion molecules [neural cell adhesion molecule (NCAM) and N-cadherin] and extracellular signal-regulated kinases (ERK) in acrylamide-treated KT98/F1B-GFP and U-1240 MG/F1B-GFP neurospheres demonstrated that NCAM decreased and phospho-ERK (pERK) increased, whereas expression of N-cadherin remained unchanged. Analysis of AKT (protein kinase B, PKB)/β-catenin pathway showed decrease in phospho-AKT (p-AKT) and cyclin D1 expression in acrylamide-treated neurospheres of KT98/F1B-GFP. Furthermore, PD98059, an ERK phosphorylation inhibitor, attenuated acrylamide-induced ERK phosphorylation, indicating that pERK contributed to the cell proliferation, but not in neurosphere formation in mouse NSPCs. Coimmunoprecipitation results of KT98/F1B-GFP cell lysates showed that the complex of NCAM and fibroblast growth factor receptor 1 (FGFR1) is present in the neurosphere, and the amount of this complex decreases after acrylamide treatment. Our results reveal that acrylamide inhibits neurosphere formation through the disruption of the neurosphere architecture in NSPCs. The downregulation of cell-cell adhesion resulted from decreasing the levels of NCAM as well as the formation of NCAM/ FGFR complex.

The potential role of angiogenic factors in rheumatoid arthritis

Angiogenesis is an important phenomenon in the pathogenesis of some diseases, such as numerous types of tumors and autoimmunity, and also a number of soluble and cell-bound factors may stimulate neovascularization in inflammatory reaction processes. Here, by highlighting the significance of angiogenesis reaction in rheumatoid arthritis (RA), we will mainly focus on the role of various growth factors, cytokines, enzymes, cells, hypoxic conditions and transcription factors in the angiogenic process and we will then explain some therapeutic strategies based on blockage of angiogenesis and modification of the vascular pathology in RA.

Aqueous ethanolic extract of Tinospora cordifolia as a potential candidate for differentiation based therapy of glioblastomas

Glioblastomas are the most aggressive primary brain tumors and their heterogeneity and complexity often renders them non responsive to various conventional treatments. Search for herbal products having potential anti-cancer activity is an active area of research in the Indian traditional system of medicine i.e., Ayurveda. Tinospora cordifolia, also named as ‘heavenly elixir’ is used in various ayurvedic decoctions as panacea to treat several body ailments. The current study investigated the anti-brain cancer potential of 50% ethanolic extract of Tinospora cordifolia (TCE) using C6 glioma cells. TCE significantly reduced cell proliferation in dose-dependent manner and induced differentiation in C6 glioma cells, resulting in astrocyte-like morphology as indicated by phase contrast images, GFAP expression and process outgrowth data of TCE treated cells which exhibited higher number and longer processes than untreated cells. Reduced proliferation of cells was accompanied by enhanced expression of senescence marker, mortalin and its translocation from perinuclear to pancytoplasmic spaces. Further, TCE showed anti-migratory and anti-invasive potential as depicted by wound scratch assay and reduced expression of plasticity markers NCAM and PSA-NCAM along with MMP-2 and 9. On analysis of the cell cycle and apoptotic markers, TCE treatment was seen to arrest the C6 cells in G0/G1 and G2/M phase, suppressing expression of G1/S phase specific protein cyclin D1 and anti-apoptotic protein Bcl-xL, thus supporting its anti-proliferative and apoptosis inducing potential. Present study provides the first evidence for the presence of anti-proliferative, differentiation-inducing and anti-migratory/anti-metastatic potential of TCE in glioma cells and possible signaling pathways involved in its mode of action. Our primary data suggests that TCE and its active components may prove to be promising phytotherapeutic interventions in gliobalstoma multiformae. 

Hijacking the neuronal NMDAR signaling circuit to promote tumor growth and invasion

Glutamate and its receptor N-methyl-D-aspartate receptor (NMDAR) have been associated with cancer, although their functions are not fully understood. Herein, we implicate glutamate-driven NMDAR signaling in a mouse model of pancreatic neuroendocrine tumorigenesis (PNET) and in selected human cancers. NMDAR was upregulated at the periphery of PNET tumors, particularly invasive fronts. Moreover, elevated coexpression of NMDAR and glutamate exporters correlated with poor prognosis in cancer patients. Treatment of a tumor-derived cell line with NMDAR antagonists impaired cancer cell proliferation and invasion. Flow conditions mimicking interstitial fluid pressure induced autologous glutamate secretion, activating NMDAR and its downstream MEK-MAPK and CaMK effectors, thereby promoting invasiveness. Congruently, pharmacological inhibition of NMDAR in mice with PNET reduced tumor growth and invasiveness. Therefore, beyond its traditional role in neurons, NMDAR may be activated in human tumors by fluid flow consequent to higher interstitial pressure, inducing an autocrine glutamate signaling circuit with resultant stimulation of malignancy.

Withania somnifera water extract as a potential candidate for differentiation based therapy of human neuroblastomas

Neuroblastoma is an aggressive childhood disease of the sympathetic nervous system. Treatments are often ineffective and have serious side effects. Conventional therapy of neuroblastoma includes the differentiation agents. Unlike chemo-radiotherapy, differentiation therapy shows minimal side effects on normal cells, because normal non-malignant cells are already differentiated. Keeping in view the limited toxicity of Withania somnifera (Ashwagandha), the current study was aimed to investigate the efficacy of Ashwagandha water extract (ASH-WEX) for anti-proliferative potential in neuroblastoma and its underlying signalling mechanisms. ASH-WEX significantly reduced cell proliferation and induced cell differentiation as indicated by morphological changes and NF200 expression in human IMR-32 neuroblastoma cells. The induction of differentiation was accompanied by HSP70 and mortalin induction as well as pancytoplasmic translocation of the mortalin in ASH-WEX treated cells. Furthermore, the ASH-WEX treatment lead to induction of neural cell adhesion molecule (NCAM) expression and reduction in its polysialylation, thus elucidating its anti-migratory potential, which was also supported by downregulation of MMP 2 and 9 activity. ASH-WEX treatment led to cell cycle arrest at G0/G1 phase and increase in early apoptotic population. Modulation of cell cycle marker Cyclin D1, anti-apoptotic marker bcl-xl and Akt-P provide evidence that ASH-WEX may prove to be a promising phytotherapeutic intervention in neuroblatoma related malignancies.

Protein-mediated interactions of pancreatic islet cells

The islets of Langerhans collectively form the endocrine pancreas, the organ that is soley responsible for insulin secretion in mammals, and which plays a prominent role in the control of circulating glucose and metabolism. Normal function of these islets implies the coordination of different types of endocrine cells, noticeably of the beta cells which produce insulin. Given that an appropriate secretion of this hormone is vital to the organism, a number of mechanisms have been selected during evolution, which now converge to coordinate beta cell functions. Among these, several mechanisms depend on different families of integral membrane proteins, which ensure direct (cadherins, N-CAM, occludin, and claudins) and paracrine communications (pannexins) between beta cells, and between these cells and the other islet cell types. Also, other proteins (integrins) provide communication of the different islet cell types with the materials that form the islet basal laminae and extracellular matrix. Here, we review what is known about these proteins and their signaling in pancreatic β -cells, with particular emphasis on the signaling provided by Cx36, given that this is the integral membrane protein involved in cell-to-cell communication, which has so far been mostly investigated for effects on beta cell functions.

Sorafenib inhibits tumor growth and improves survival in a transgenic mouse model of pancreatic islet cell tumors

BACKGROUND

The purpose of the study was to evaluate Sorafenib (BAY 43-9006) derived receptor tyrosine kinase inhibition on tumor progression in murine islet cell tumors. Sorafenib is considered to be a potent inhibitor of tumor angiogenesis and neovascularization in various solid tumors. Rip1Tag2 mice were treated in two different groups according to the model of tumor progression: the early treatment group received vehicle or Sorafenib from 10 to 14 weeks of age and the late treatment group from week 12 until death. Tumor surface, tumor cell proliferation, and apoptosis were measured in both treatment groups to assess the in vivo effects of Sorafenib. Survival was recorded for the late treatment group. In the early treatment group Sorafenib led to a dramatic decrease in tumor volume compared to the control group. Apoptosis was significantly augmented and cell proliferation was inhibited. As a single therapy Sorafenib significantly improved survival in the late treatment group. Conclusion. Sorafenib may provide a new paradigm for the therapy of islet cell tumors.

Hypoxia inducible factor-1α is necessary for invasive phenotype in Vegf-deleted islet cell tumors

In the mouse model of pancreas endocrine tumor, loss of Vegf (VKO) results in dramatically decreased tumor progression; however, the residual microscopic lesions show increased invasion into surrounding exocrine tissue. Double KO mice of Vegf and hypoxia inducible factor-1α (Hif-1α) showed increased life span and suppressed tumor growth due to increased apoptosis. The increased invasiveness of tumors in VKO mice was diminished in DKO mice to the levels of wild-type mice. Compared to VKO mice, DKO mice also exhibited smaller changes in the expression levels of adhesion molecules, including E-cadherin, N-cadherin, and NCAM. These changes of adhesion molecules were not observed in the primary culture of the tumor cells under hypoxic conditions. Thus, the invasive phenotype observed under angiogenesis inhibition requires Hif-1α, but is not directly caused by acute hypoxia.

Anti-VEGF antibody therapy does not promote metastasis in genetically engineered mouse tumour models

Resistance to anti-angiogenic therapy can occur via several potential mechanisms. Unexpectedly, recent studies showed that short-term inhibition of either VEGF or VEGFR enhanced tumour invasiveness and metastatic spread in preclinical models. In an effort to evaluate the translational relevance of these findings, we examined the consequences of long-term anti-VEGF monoclonal antibody therapy in several well-validated genetically engineered mouse tumour models of either neuroendocrine or epithelial origin. Anti-VEGF therapy decreased tumour burden and increased overall survival, either as a single agent or in combination with chemotherapy, in all four models examined. Importantly, neither short- nor long-term exposure to anti-VEGF therapy altered the incidence of metastasis in any of these autochthonous models, consistent with retrospective analyses of clinical trials. In contrast, we observed that sunitinib treatment recapitulated previously reported effects on tumour invasiveness and metastasis in a pancreatic neuroendocrine tumour (PNET) model. Consistent with these results, sunitinib treatment resulted in an up-regulation of the hypoxia marker GLUT1 in PNETs, whereas anti-VEGF did not. These results indicate that anti-VEGF mediates anti-tumour effects and therapeutic benefits without a paradoxical increase in metastasis. Moreover, these data underscore the concept that drugs targeting VEGF ligands and receptors may affect tumour metastasis in a context-dependent manner and are mechanistically distinct from one another.

Beyond VEGF: inhibition of the fibroblast growth factor pathway and antiangiogenesis

Fibroblast growth factor (FGF) signaling regulates cell proliferation, differentiation, survival, angiogenesis, and wound healing. Compelling evidence for deregulated FGF signaling in tumorigenesis continues to emerge, and a growing body of research suggests that FGF may also play an integral role in the resistance to anti-VEGF therapy. Although agents targeting FGF signaling are early in development, the potential to target both the VEGF and FGF pathways may translate into improvements in the clinical care of cancer patients.

A novel role for neural cell adhesion molecule in modulating insulin signaling and adipocyte differentiation of mouse mesenchymal stem cells

Neural cell adhesion molecule (NCAM) has recently been found on adult stem cells, but its biological significance remains largely unknown. In this study, we used bone-marrow-derived mesenchymal stem cells (MSCs) from wild-type and NCAM knockout mice to investigate the role of NCAM in adipocyte differentiation. It was demonstrated that NCAM isoforms 180 and 140 but not NCAM-120 are expressed on almost all wild-type MSCs. Upon adipogenic induction, Ncam(-/-) MSCs exhibited a marked decrease in adipocyte differentiation compared with wild-type cells. The role of NCAM in adipocyte differentiation was also confirmed in NCAM-silenced preadipocyte 3T3-L1 cells, which also had a phenotype with reduced adipogenic potential. In addition, we found that Ncam(-/-) MSCs appeared to be insulin resistant, as shown by their impaired insulin signaling cascade, such as the activation of the insulin-IGF-1 receptor, PI3K-Akt and CREB pathways. The PI3K-Akt inhibitor, LY294002, completely blocked adipocyte differentiation of MSCs, unveiling that the reduced adipogenic potential of Ncam(-/-) MSCs is due to insulin resistance as a result of loss of NCAM function. Furthermore, insulin resistance of Ncam(-/-) MSCs was shown to be associated with induction of tumor necrosis factor α (TNF-α), a key mediator of insulin resistance. Finally, we demonstrated that re-expression of NCAM-180, but not NCAM-140, inhibits induction of TNF-α and thereby improves insulin resistance and adipogenic potential of Ncam(-/-) MSCs. Our results suggest a novel role of NCAM in promoting insulin signaling and adipocyte differentiation of adult stem cells. These findings raise the possibility of using NCAM intervention to improve insulin resistance.

Attenuated liver fibrosis after bile duct ligation and defective hepatic stellate cell activation in neural cell adhesion molecule knockout mice

AIM

Neural cell adhesion molecule (N-CAM) is expressed by activated hepatic stellate cells (HSC), portal fibroblasts, cholangiocytes and hepatic progenitor cells during liver injury. Its functional role in liver disease and fibrogenesis is unknown. The aim of this study was to investigate the role of N-CAM in liver fibrogenesis.

METHODS

To induce fibrosis, N-CAM knockout mice and wild-type controls were subjected to bile duct ligation (BDL) or repeated carbon tetrachloride (CCl(4) ) injections. Fibrosis was quantified by hydroxyproline, immunhistochemistry staining and image analysis. Protein levels were determined with immunoblotting. HSCs were isolated by ultracentrifugation in a Larcoll gradient and thereafter in vitro stimulated with recombinant transforming growth factor (TGF)-β1.

RESULTS

Two weeks after BDL, wild-type mice had developed pronounced liver fibrosis while N-CAM-/- mice had less such alterations. N-CAM-/- mice had less deposition of collagen and fibronectin seen in immunhistochemistry. The protein levels of fibronectin were higher in the liver from the wild type, while laminin were unaltered. CCl(4) -treated N-CAM-/- and wild-type mice showed no significant difference in the extent of liver fibrosis or the expression levels of the above-mentioned genes. HSC isolated from N-CAM-/- mice showed declined levels of smooth muscle actin and desmin after stimulation in vitro with TGF-β1.

CONCLUSIONS

Loss of N-CAM results in decreased hepatic collagen and fibronectin deposition in mice subjected to BDL, but not in animals exposed to repeated CCl(4) injections. HSC isolated from N-CAM null mice show impaired activation in vitro. This indicates a role of N-CAM in cholestatic liver disease and HSC activation.

Hedgehog inhibition with cyclopamine represses tumor growth and prolongs survival in a transgenic mouse model of islet cell tumors

BACKGROUND

Blockade of aberrant hedgehog (Hh) activation has recently been proposed as a therapeutic target, but effects in models of islet cell tumors have not been examined. In this study, we address the role of the Hh pathway in tumor progression of murine islet cell tumors.

METHODS

To assess in vivo effects, Rip1Tag2 mice were treated with vehicle or cyclopamine (25 mg/kg/d) (n = 10 in each group). The effect of hedgehog pathway inhibition on survival was determined by continuous application of the small molecule smoothened antagonist cyclopamine.

RESULTS

Hh-inhibition was confirmed by downregulation of Hh-target genes. Cyclopamine response was associated with increased apoptosis, decreased tumor cell proliferation and reduced tumor volume. Furthermore, hedgehog inhibition with cyclopamine significantly prolonged median survival in the used transgenic mouse model (102 vs 124 days; P = 0.02).

CONCLUSIONS

Thus, Hh inhibitors may provide a new paradigm for therapy of islet cell tumors in various stages, particularly their use in conjunction with conventional antimetabolites should be further evaluated.

Water extract of ashwagandha leaves limits proliferation and migration, and induces differentiation in glioma cells

Root extracts of Withania somnifera (Ashwagandha) are commonly used as a remedy for a variety of ailments and a general tonic for overall health and longevity in the Indian traditional medicine system, Ayurveda. We undertook a study to investigate the anti-proliferative and differentiation-inducing activities in the water extract of Ashwagandha leaves (ASH-WEX) by examining in glioma cells. Preliminary detection for phytochemicals was performed by thin-layer chromatography. Cytotoxicity was determined using trypan blue and MTT assays. Expression level of an hsp70 family protein (mortalin), glial cell differentiation marker [glial fibrillary acidic protein (GFAP)] and neural cell adhesion molecule (NCAM) were analyzed by immunocytochemistry and immunoblotting. Anti-migratory assay was also done using wound-scratch assay. Expression levels of mortalin, GFAP and NCAM showed changes, subsequent to the treatment with ASH-WEX. The data support the existence of anti-proliferative, differentiation-inducing and anti-migratory/anti-metastasis activities in ASH-WEX that could be used as potentially safe and complimentary therapy for glioma.

Treatment with Sitengfang decreases cell adhesion, invasion and migration in human gastric carcinoma cell line SGC-7901

AIM: To investigate the influence of treatment with Sitengfang on cell adhesion, invasion and migration in human gastric carcinoma cell line SGC-7901.

METHODS: SGC-7901 cells were cultured in vitro and treated with different concentration of Sitengfang (0, 50, 100 and 200 mg/L, respectively). Cell adhesion was detected by CytoSelect^TM 48-Well Cell Adhesion Assay. Cell invasion was analyzed by Transwell invasion assay. Cell migration was detected by scratch wound healing assay.

RESULTS: Treatment with Sitengfang at a concentration of 50, 100 or 200 mg/L significantly inhibited the adhesion and invasion of SGC-7901 cells (adhesion: 0.34 ± 0.05, 0.13 ± 0.00, 0.12 ± 0.01 vs 1.34 ± 0.12; invasion: 39 ± 3, 26 ± 6, 8 ± 2 vs 80 ± 5, all P < 0.01). Wound healing assay showed a significant reduction in the migration capacity of cells treated with 50 mg/L Sitengfang for 48 h (28.57% ± 4.10% vs 59.68% ± 5.98%, P < 0.01).

CONCLUSION: Treatment with Sitengfang significantly decreases cell adhesion, invasion and migration in human gastric carcinoma cell line SGC-7901.

Clinicopathological analysis of CD133 and NCAM human hepatic stem/progenitor cells in damaged livers and hepatocellular carcinomas

AIM

Hepatic stem cells are capable of dramatically changing and differentiating to form mature hepatocytes in acute and chronically damaged livers; however, the clinicopathological characteristics of these heterogeneous cell populations have not been sufficiently analyzed.

METHODS

In this study, cells in tissue sections from 12 cases of acute damaged livers and 31 cases of hepatocellular carcinomas (HCC), and the surrounding chronically damaged liver tissues, were analyzed by immunohistochemistry using the previously reported hepatic stem/progenitor cell marker CD133 (AC133) and the neural cell adhesion molecule (NCAM) marker.

RESULTS

In both the acute and chronically damaged livers, CD133(+) cells and NCAM(+) cells were present in ductular reactions (DR), which include hepatic stem/progenitor cells, and became more apparent in proportion to the degree of fibrosis or histological damage. Analysis of their distribution and morphological similarities revealed that the NCAM(+) cell population included cells that were closer to, and morphologically more similar to, hepatocytes than were CD133(+) cells. Analysis of HCC using these markers revealed that 9.7% of HCC expressed NCAM (two cases had abundant NCAM(+) cells), while CD133(+) HCC were not detected.

CONCLUSION

These results suggest that CD133 and NCAM can be employed to enrich for hepatic stem/progenitor cells and that DR can be distinguished in greater detail using these markers. NCAM(+) HCC were detected, but their function remains unresolved. Expression of CD133, a potent stem cell marker, may be extremely rare in the common human HCC examined.

Metastasis mechanisms

Metastasis, the spread of malignant cells from a primary tumor to distant sites, poses the biggest problem to cancer treatment and is the main cause of death of cancer patients. It occurs in a series of discrete steps, which have been modeled into a "metastatic cascade". In this review, we comprehensively describe the molecular and cellular mechanisms underlying the different steps, including Epithelial-Mesenchymal Transition (EMT), invasion, anoikis, angiogenesis, transport through vessels and outgrowth of secondary tumors. Furthermore, we implement recent findings that have broadened and challenged the classical view on the metastatic cascade, for example the establishment of a "premetastatic niche", the requirement of stem cell-like properties, the role of the tumor stroma and paracrine interactions of the tumor with cells in distant anatomical sites. A better understanding of the molecular processes underlying metastasis will conceivably present us with novel targets for therapeutic intervention.

Recurrence of pleomorphic adenoma of the parotid gland--predictive value of cadherin-11 and fascin

The predictive value of cadherin-11, tenascin, fascin, and mucin-1 as markers for the likelihood of recurrence in pleomorphic adenoma of the parotid gland was examined. In this retrospective study we analysed 20 tumours from16 patients by immunohistochemistry. Staining intensities were measured using a semiquantitative scoring approach; localisation (tumour centre vs border) as well as clinical data were analysed and correlated with follow-up. Cadherin-11 was increased in recurrent tumours. However, no changes of fascin, tenascin or mucin-1 were observed. Cadherin-11 and fascin were increased in primary tumours of patients with later recurrence, with fascin upregulation restricted to the tumour border. In conclusion, cadherin-11 and fascin should be further analysed for their value as markers for later recurrence in pleomorphic adenoma. Our observations might reflect dysregulation of cellular pathways contributing to cellular dissemination, which might potentially result in later recurrence.

Differential effects of the vascular endothelial growth factor receptor inhibitor PTK787/ZK222584 on tumor angiogenesis and tumor lymphangiogenesis

Halting tumor growth by interfering with tumor-induced angiogenesis is an attractive therapeutic approach. Such treatments include humanized antibodies blocking the activity of vascular endothelial growth factor (VEGF)-A (bevacizumab), soluble VEGF receptor (VEGFR) constructs (VEGF-Trap), or small-molecule inhibitors of VEGFR signaling, including PTK787/ZK222584 (PTK/ZK), sorafenib, and sunitinib. PTK/ZK has been shown previously to specifically block VEGF-induced phosphorylation of VEGFR-1, -2 and -3 and thereby to inhibit endothelial cell proliferation, differentiation, and tumor angiogenesis. We have investigated the effect of PTK/ZK on tumor angiogenesis and tumor lymphangiogenesis using the Rip1Tag2 transgenic mouse model of pancreatic beta cell carcinogenesis. In Rip1Tag2 mice, tumor angiogenesis is predominantly mediated by VEGF-A, and as expected, PTK/ZK efficiently impaired tumor blood vessel angiogenesis and tumor growth. Double-transgenic Rip1Tag2;Rip1VEGF-C and Rip1Tag2;Rip1VEGF-D mice not only exhibit VEGF-A-dependent blood vessel angiogenesis but also tumor lymphangiogenesis induced by the transgenic expression of VEGF-C or -D. In these mouse models, PTK/ZK also repressed tumor blood vessel angiogenesis and tumor growth yet failed to affect tumor lymphangiogenesis and lymphogenic metastasis. Adenoviral delivery of soluble VEGFR-3 also did not prevent tumor lymphangiogenesis in these mice. In contrast, spontaneous tumor lymphangiogenesis, as observed by the stochastic expression of VEGF-C and -D in tumors of neural cell adhesion molecule-deficient Rip1Tag2 mice, was repressed by PTK/ZK and soluble VEGFR-3. The results indicate that the time of onset and the levels of VEGF-C/D expression may be critical variables in efficiently repressing tumor lymphangiogenesis and that pathways other than VEGFR signaling may be involved in tumor lymphangiogenesis.

Membrane and membrane-associated proteins involved in the aggressive phenotype displayed by highly invasive cancer cells

Invasion, the penetration of tumour cells into adjacent tissues, is a fundamental characteristic of malignant carcinomas and a first step in the metastatic process. The molecular mechanisms involved in tumour cell invasion are complex, but over the last couple of decades the knowledge base has grown quite considerably and many proteins with important roles in invasion have been identified and characterised. Benign tumours typically are encapsulated, which inhibits their ability to behave in a malignant manner, meaning these tumours do not grow in a location-limited less aggressive manner, do not invade surrounding tissues and do not metastasise. The ability of malignant tumours to invade and metastasise is the major cause of death for cancer patients. A greater insight into the molecular basis of cancer invasion and metastasis will lead to the development of novel therapies and specific panels of biomarkers for use in the treatment and diagnosis/monitoring in many types of metastatic cancer.

NCAM is at the heart of reciprocal regulation of E-cadherin- and integrin-mediated adhesions via signaling modulation

New work by Lehembre et al. in The EMBO Journal reveals that the cell-adhesion molecule, NCAM, is at the heart of crosstalk between E-cadherin loss and reciprocal focal adhesion assembly during the epithelial to mesenchymal transition (EMT). NCAM upregulation induces the formation of novel signaling complexes that correlate with NCAM-dependent focal adhesion assembly, migration, and cancer cell invasion.

NCAM-induced focal adhesion assembly: a functional switch upon loss of E-cadherin

Loss of expression of the cell-cell adhesion molecule E-cadherin is a hallmark of epithelial-mesenchymal transition (EMT) in development and in the progression from epithelial tumours to invasive and metastatic cancers. Here, we demonstrate that the loss of E-cadherin function upregulates expression of the neuronal cell adhesion molecule (NCAM). Subsequently, a subset of NCAM translocates from fibroblast growth factor receptor (FGFR) complexes outside lipid rafts into lipid rafts where it stimulates the non-receptor tyrosine kinase p59(Fyn) leading to the phosphorylation and activation of focal adhesion kinase and the assembly of integrin-mediated focal adhesions. Ablation of NCAM expression during EMT inhibits focal adhesion assembly, cell spreading and EMT. Conversely, forced expression of NCAM induces epithelial cell delamination and migration, and high NCAM expression correlates with tumour invasion. These results establish a mechanistic link between the loss of E-cadherin expression, NCAM function, focal adhesion assembly and cell migration and invasion.

Expression of CD56 isoforms in primary and relapsed adult granulosa cell tumors of the ovary

BACKGROUND

Adult granulosa cell tumors of the ovary (GCTs) are sex cord stromal tumors of unpredictable behaviour. Up to now, the prediction of the relapsing/malignant potential remains difficult. CD56 (NCAM) in GCTs was previously described in only two studies. However, the expression of its isoforms was not examined.

METHODS

30 GCTs (16 primaries, 14 relapses) were investigated immunohistochemically with antibodies against Pan-CD56 (CD56Pan) and the isoform with 140/180 kDa length (CD56140/180 kDa). The reaction was assessed with respect to percentage of positive cells and intensity of staining.

RESULTS

In all GCTs, CD56Pan was expressed, but differences were found between primaries and relapses. The percentage of CD56Pan positive tumor cells was lower in relapses, whereas CD56140/180 kDa showed a higher staining intensity in the latter.

CONCLUSION

Expression of CD56 is an additional sensitive and helpful immunohistochemical tool for histopathologists diagnosing a GCT. It does not seem possible to provide a validly individual risk assessment. However, the different expression of CD56 isoforms might indicate important changes in the course to a more malignant behaviour.

Neural cell adhesion molecule (NCAM) isoform expression is associated with neuroblastoma differentiation status

BACKGROUND

NCAM is a member of the immunoglobulin superfamily of cell adhesion molecules. While highly expressed on neuroblastoma cells, the relative contribution of the three major NCAM isoforms (120, 140, and 180 kDa) to neuroblastoma biology has not been investigated.

METHODS

NCAM protein expression was measured in a neuroblastic tumor tissue microarray (N = 185) by immunohistochemistry. Relative expression of NCAM mRNA isoforms was measured in a panel of 24 human neuroblastomas and compared to fetal and adult human brain using real-time quantitative PCR and Western blot analysis. Associations with clinical and tumor biological co-variates were performed.

RESULTS

NCAM protein was detected on all neuroblastic tumors and was highly expressed in all but 7/167 cases. The mRNA species predicted to encode the 120 kDa protein species was the most abundant isoform in adult brain, ganglioneuromas and ganglioneuroblastomas (P = 0.0007), but the mRNA predicted to encode the 180 kDa species was predominant in neuroblastomas (P = 0.043). Microdissected ganglion and neuroblast cells from human primary tumors confirmed these findings.

CONCLUSION

Ganglioneuromas and ganglioneuroblastomas express the adhesive 120 kDa NCAM isoform, while neuroblastomas preferentially express the 180 kDa isoform classically involved in cell motility. These data suggest a mechanism for the enhanced metastatic potential of undifferentiated neuroblastomas.

Basolateral junctions utilize warts signaling to control epithelial-mesenchymal transition and proliferation crucial for migration and invasion of Drosophila ovarian epithelial cells

Fasciclin2 (Fas2) and Discslarge (Dlg) localize to the basolateral junction (BLJ) of Drosophila follicle epithelial cells and inhibit their proliferation and invasion. To identify a BLJ signaling pathway we completed a genomewide screen for mutants that enhance dlg tumorigenesis. We identified two genes that encode known BLJ scaffolding proteins, lethal giant larvae (lgl) and scribble (scrib), and several not previously associated with BLJ function, including warts (wts) and roughened eye (roe), which encode a serine-threonine kinase and a transcription factor, respectively. Like scrib, wts and roe also enhance Fas2 and lgl tumorigenesis. Further, scrib, wts, and roe block border cell migration, and cause noninvasive tumors that resemble dlg partial loss of function, suggesting that the BLJ utilizes Wts signaling to repress EMT and proliferation, but not motility. Apicolateral junction proteins Fat (Ft), Expanded (Ex), and Merlin (Mer) either are not involved in these processes, or have highly spatio-temporally restricted roles, diminishing their significance as upstream inputs to Wts in follicle cells. This is further indicated in that Wts targets, CyclinE and DIAP1, are elevated in Fas2, dlg, lgl, wts, and roe cells, but not Fat, ex, or mer cells. Thus, the BLJ appears to regulate epithelial polarity and dynamics not only as a localized scaffold, but also by communicating signals to the nucleus. Wts may be regulated by distinct junction inputs depending on developmental context.

CADM1 is a strong neuroblastoma candidate gene that maps within a 3.72 Mb critical region of loss on 11q23

Background

Recurrent loss of part of the long arm of chromosome 11 is a well established hallmark of a subtype of aggressive neuroblastomas. Despite intensive mapping efforts to localize the culprit 11q tumour suppressor gene, this search has been unsuccessful thus far as no sufficiently small critical region could be delineated for selection of candidate genes.

Methods

To refine the critical region of 11q loss, the chromosome 11 status of 100 primary neuroblastoma tumours and 29 cell lines was analyzed using a BAC array containing a chromosome 11 tiling path. For the genes mapping within our refined region of loss, meta-analysis on published neuroblastoma mRNA gene expression datasets was performed for candidate gene selection. The DNA methylation status of the resulting candidate gene was determined using re-expression experiments by treatment of neuroblastoma cells with the demethylating agent 5-aza-2'-deoxycytidine and bisulphite sequencing.

Results

Two small critical regions of loss within 11q23 at chromosomal band 11q23.1-q23.2 (1.79 Mb) and 11q23.2-q23.3 (3.72 Mb) were identified. In a first step towards further selection of candidate neuroblastoma tumour suppressor genes, we performed a meta-analysis on published expression profiles of 692 neuroblastoma tumours. Integration of the resulting candidate gene list with expression data of neuroblastoma progenitor cells pinpointed CADM1 as a compelling candidate gene. Meta-analysis indicated that CADM1 expression has prognostic significance and differential expression for the gene was noted in unfavourable neuroblastoma versus normal neuroblasts. Methylation analysis provided no evidence for a two-hit mechanism in 11q deleted cell lines.

Conclusion

Our study puts CADM1 forward as a strong candidate neuroblastoma suppressor gene. Further functional studies are warranted to elucidate the role of CADM1 in neuroblastoma development and to investigate the possibility of CADM1 haploinsufficiency in neuroblastoma.

B-Raf is required for ERK activation and tumor progression in a mouse model of pancreatic beta-cell carcinogenesis

Activation of the Raf/MEK/ERK pathway, often by gain-of-function mutations of RAS or RAF, is observed in many human cancers. The extracellular signal-regulated kinase (ERK) pathway is required for the proliferation of cancer cell lines harboring activating BRAF or, to a lesser extent, activating RAS mutations. It is still unclear, however, whether the pathway is required in vivo for tumor development, particularly in tumors in which B-Raf is not mutationally activated. During embryonic development, B-Raf is essential for angiogenesis in the placenta. To address the question of whether B-Raf contributed to tumor angiogenesis in vivo we conditionally ablated B-Raf in a model of pancreatic islet carcinoma driven by the functional inactivation of tumor suppressors (RIP1Tag2), which critically depends on angiogenesis for growth. We find that B-Raf is dispensable for the proliferation of tumor cells in culture, but necessary for ERK activation and for the expression of angiogenic factors by tumor cells in vivo and in vitro. In vivo, these defects result in the formation of hollow tumors with decreased vessel density and strongly reduced proliferation. The progression from adenoma to carcinoma is also significantly impaired. Thus, endogenous B-Raf contributes to the development of RIP1Tag2 tumors by supporting the stromal response and tumor progression.

Metastatic cancer cell

Metastasis is the result of cancer cell adaptation to a tissue microenvironment at a distance from the primary tumor. Metastatic cancer cells require properties that allow them not only to adapt to a foreign microenvironment but to subvert it in a way that is conducive to their continued proliferation and survival. Recent conceptual and technological advances have contributed to our understanding of the role of the host tissue stroma in promoting tumor cell growth and dissemination and have provided new insight into the genetic makeup of cancers with high metastatic proclivity.

Neural cell adhesion molecule regulates the cellular response to fibroblast growth factor

Neural cell adhesion molecule (NCAM) mediates cell-cell adhesion and signaling in the nervous system, yet NCAM is also expressed in non-neural tissues, in which its function has in most parts remained elusive. We have previously reported that NCAM stimulates cell-matrix adhesion and neurite outgrowth by activating fibroblast growth factor receptor (FGFR) signaling. Here, we investigated whether the interplay between NCAM and FGFR has any impact on the response of FGFR to its classical ligands, FGFs. To this end, we employed two fibroblast cell lines, NCAM-negative L cells and NCAM-positive NIH-3T3 cells, in which the expression of NCAM was manipulated by means of transfection or RNAi technologies, respectively. The results demonstrate that NCAM expression reduces FGF-stimulated ERK1/2 activation, cell proliferation and cell-matrix adhesion, in both L and NIH-3T3 cells. Furthermore, our data show that NCAM inhibits the binding of FGF to its high-affinity receptor in a competitive manner, providing the mechanisms for the NCAM-mediated suppression of FGF function. In this context, a small peptide that mimics the binding of NCAM to FGFR was sufficient to block FGF-dependent cell proliferation. These findings point to NCAM as being a major regulator of FGF-FGFR interaction, thus introducing a novel type of control mechanism for FGFR activity and opening new therapeutic perspectives for those diseases characterized by aberrant FGFR function.

Neural cell adhesion molecule-180 expression as a prognostic criterion in colorectal carcinoma: Feasible or not?

AIM: To evaluate the frequency of neural cell adhesion molecule (NCAM)-180 expression in fresh tumor tissue samples and to discuss the prognostic value of NCAM-180 in routine clinical practice.

METHODS: Twenty-six patients (16 men, 10 women) with colorectal cancer were included in the study. Fresh tumor tissue samples and macroscopically healthy proximal margins of each specimen were subjected to flow-cytometric analysis for NCAM-180 expression.

RESULTS: Flow-cytometric analysis determined NCAM-180 expression in whole tissue samples of macroscopically healthy colorectal tissues. However, NCAM-180 expression was positive in only one case (3.84%) with well-differentiated Stage II disease who experienced no active disease at 30 mon follow-up.

CONCLUSION: As a consequence of the limited number of cases in our series, it might not be possible to make a generalisation, nevertheless the routine use of NCAM-180 expression as a prognostic marker for colorectal carcinoma seems to be unfeasible and not cost-effective in clinical practice due to its very low incidence.