Cell adhesion molecules of the immunoglobulin supergene family and their role in malignant transformation and progression to metastatic disease

The Glycosaminoglycan Side Chains and Modular Core Proteins of Heparan Sulphate Proteoglycans and the Varied Ways They Provide Tissue Protection by Regulating Physiological Processes and Cellular Behaviour

This review examines the roles of HS-proteoglycans (HS-PGs) in general, and, in particular, perlecan and syndecan as representative examples and their interactive ligands, which regulate physiological processes and cellular behavior in health and disease. HS-PGs are essential for the functional properties of tissues both in development and in the extracellular matrix (ECM) remodeling that occurs in response to trauma or disease. HS-PGs interact with a biodiverse range of chemokines, chemokine receptors, protease inhibitors, and growth factors in immune regulation, inflammation, ECM stabilization, and tissue protection. Some cell regulatory proteoglycan receptors are dually modified hybrid HS/CS proteoglycans (betaglycan, CD47). Neurexins provide synaptic stabilization, plasticity, and specificity of interaction, promoting neurotransduction, neurogenesis, and differentiation. Ternary complexes of glypican-1 and Robbo-Slit neuroregulatory proteins direct axonogenesis and neural network formation. Specific neurexin-neuroligin complexes stabilize synaptic interactions and neural activity. Disruption in these interactions leads to neurological deficits in disorders of functional cognitive decline. Interactions with HS-PGs also promote or inhibit tumor development. Thus, HS-PGs have complex and diverse regulatory roles in the physiological processes that regulate cellular behavior and the functional properties of normal and pathological tissues. Specialized HS-PGs, such as the neurexins, pikachurin, and Eyes-shut, provide synaptic stabilization and specificity of neural transduction and also stabilize the axenome primary cilium of phototoreceptors and ribbon synapse interactions with bipolar neurons of retinal neural networks, which are essential in ocular vision. Pikachurin and Eyes-Shut interactions with an α-dystroglycan stabilize the photoreceptor synapse. Novel regulatory roles for HS-PGs controlling cell behavior and tissue function are expected to continue to be uncovered in this fascinating class of proteoglycan.

Bone Metastasis in Bladder Cancer

Bladder cancer (BCa) is the 10th most common and 13th most deadly malignancy worldwide. About 5% of BCa patients present initially with metastatic disease, with bone being the most diagnosed site for distant metastasis. The overall one-year survival of patients with BCa is 84%, whereas it is only 21% in patients with bone metastasis (BM). Metastasis of BCa cells to bone occurs by epithelial-to-mesenchymal transition, angiogenesis, intravasation, extravasation, and interactions with the bone microenvironment. However, the mechanism of BCa metastasis to the bone is not completely understood; it needs a further preclinical model to completely explain the process. As different imaging mechanisms, PET-CT cannot replace a radionuclide bone scan or an MRI for diagnosing BM. The management of BCa patients with BM includes chemotherapy, immunotherapy, targeted therapy, antibody-drug conjugates, bisphosphonates, denosumab, radioisotopes, and surgery. The objective of these treatments is to inhibit disease progression, improve overall survival, reduce skeletal-related events, relieve pain, and improve the quality of life of patients.

ALKBH1-8 and FTO: Potential Therapeutic Targets and Prognostic Biomarkers in Lung Adenocarcinoma Pathogenesis

The AlkB family consists of Fe(II)- and α-ketoglutarate-dependent dioxygenases that can catalyze demethylation on a variety of substrates, such as RNA and DNA, subsequently affecting tumor progression and prognosis. However, their detailed functional roles in lung adenocarcinoma (LUAD) have not been clarified in a comprehensive manner. In this study, several bioinformatics databases, such as ONCOMINE, TIMER, and DiseaseMeth, were used to evaluate the expression profiles and prognostic significance of the AlkB family (ALKBH1-8 and FTO) in LUAD. The expression levels of ALKBH1/2/4/5/7/8 were significantly increased in LUAD tissues, while the expression levels of ALKBH3/6 and FTO were decreased. The main functions of differentially expressed AlkB homologs are related to the hematopoietic system and cell adhesion molecules. We also found that the expression profiles of the AlkB family are highly correlated with infiltrating immune cells (i.e., B cells, CD8 + T cells, CD4 + T cells, macrophages, neutrophils and dendritic cells). In addition, DNA methylation analysis indicated that the global methylation levels of ALKBH1/2/4/5/6/8 and FTO were decreased, while the global methylation levels of ALKBH3/7 were increased. In addition, the patients with upregulated ALKBH2 have significantly poor overall survival (OS) and post-progressive survival (PPS). Taken together, our work could provide insightful information about aberrant AlkB family members as potential biomarkers for the diagnostic and prognostic evaluation of LUAD. Especially, ALKBH2 could be served as a therapeutic candidate for treating LUAD.

MicroRNA profiling in BEAS-2B cells exposed to alpha radiation reveals potential biomarkers for malignant cellular transformation

The carcinogenicity of radon has been convincingly documented through epidemiological studies of underground miners. The risk of lung cancer from radon exposure is due to the continuous radioactive decay of this gas and subsequent emission of high-energy alpha decay particles. And the bronchial epithelial cells are the main targets of radon exposure. However, there is a lack of early warning indicators of lung cancer caused by radon in the physical examination of populations involved in occupations with higher exposure to radon. To assess the potential of a molecular-based marker approach for the early detection of human lung cancer induced by radon, human bronchial epithelial cell injury models induced by alpha-particle irradiation were constructed. The results of transwell migration assay, transwell invasion assay, and the expression of the epithelial-mesenchymal transition-related proteins showed that malignant cell transformation could be triggered by alpha irradiation. Potential microRNAs (miRNAs) (hsa-miR-3907, hsa-miR-6732-3p, hsa-miR-4788, hsa-miR-5001-5p, and hsa-miR-4257) were screened using miRNA chips in cell models. The pathway analyses of miRNAs selected using DIANA-miRPath v3.0 showed that miRNAs involved in malignant cell transformation were associated with cell adhesion molecules, extracellular matrix receptor interaction, and proteoglycans in cancer, among others, which are closely related to the occurrence and development of carcinogenesis. Reverse Transcription Quantitative Real-Time PCR (RT-qPCR) assay showed that five screened miRNAs were up-regulated in five lung cancer tissue samples. In conclusion, the results indicated that hsa-miR-3907, hsa-miR-6732-3p, hsa-miR-4788, hsa-miR-5001-5p, and hsa-miR-4257 may be potential early markers of the malignant transformation of bronchial epithelial cells induced by alpha-particle irradiation.

Prion Protein at the Leading Edge: Its Role in Cell Motility

Cell motility is a central process involved in fundamental biological phenomena during embryonic development, wound healing, immune surveillance, and cancer spreading. Cell movement is complex and dynamic and requires the coordinated activity of cytoskeletal, membrane, adhesion and extracellular proteins. Cellular prion protein (PrPC) has been implicated in distinct aspects of cell motility, including axonal growth, transendothelial migration, epithelial-mesenchymal transition, formation of lamellipodia, and tumor migration and invasion. The preferential location of PrPC on cell membrane favors its function as a pivotal molecule in cell motile phenotype, being able to serve as a scaffold protein for extracellular matrix proteins, cell surface receptors, and cytoskeletal multiprotein complexes to modulate their activities in cellular movement. Evidence points to PrPC mediating interactions of multiple key elements of cell motility at the intra- and extracellular levels, such as integrins and matrix proteins, also regulating cell adhesion molecule stability and cell adhesion cytoskeleton dynamics. Understanding the molecular mechanisms that govern cell motility is critical for tissue homeostasis, since uncontrolled cell movement results in pathological conditions such as developmental diseases and tumor dissemination. In this review, we discuss the relevant contribution of PrPC in several aspects of cell motility, unveiling new insights into both PrPC function and mechanism in a multifaceted manner either in physiological or pathological contexts.

Neuroligin 4X overexpression in human breast cancer is associated with poor relapse-free survival

The molecular mechanisms involved in breast cancer progression and metastasis still remain unclear to date. It is a heterogeneous disease featuring several different phenotypes with consistently different biological characteristics. Neuroligins are neural cell adhesion molecules that have been implicated in heterotopic cell adhesion. In humans, alterations in neuroligin genes are implicated in autism and other cognitive diseases. Until recently, neuroligins have been shown to be abundantly expressed in blood vessels and also play a role implicated in the growth of glioma cells. Here we report increased expression of neuroligin 4X (NLGN4X) in breast cancer. We found NLGN4X was abundantly expressed in breast cancer tissues. NLGN4X expression data for all breast cancer cell lines in the Cancer Cell Line Encyclopedia (CCLE) was analyzed. Correlation between NLGN4X levels and clinicopathologic parameters were analyzed within Oncomine datasets. Evaluation of these bioinfomatic datasets results revealed that NLGN4X expression was higher in triple negative breast cancer cells, particularly the basal subtype and tissues versus non-triple-negative sets. Its level was also observed to be higher in metastatic tissues. RT-PCR, flow cytometry and immunofluorescence study of MDA-MB-231 and MCF-7 breast cancer cells validated that NLGN4X was increased in MDA-MB-231. Knockdown of NLGN4X expression by siRNA decreased cell proliferation and migration significantly in MDA-MB-231 breast cancer cells. NLGN4X knockdown in MDA-MB-231 cells resulted in induction of apoptosis as determined by annexin staining, elevated caspase 3/7 and cleaved PARP by flow cytometry. High NLGN4X expression highly correlated with decrease in relapse free-survival in TNBC. NLGN4X might represent novel biomarkers and therapeutic targets for breast cancer. Inhibition of NLGN4X may be a new target for the prevention and treatment of breast cancer.

Histopathological expression analysis of intercellular adhesion molecule 1 (ICAM-1) along development and progression of human melanoma

Intercellular adhesion molecule 1 (ICAM-1) protein is an important adhesion molecule that facilitates metastasis on one hand, and on the other hand supports the immunological synapse necessary for T-cell mediated elimination. The expression pattern of ICAM-1 in melanoma was studied more than two decades ago, mainly in cell lines or in unmatched melanoma specimens. By using real time PCR we could not demonstrate a clear difference in ICAM-1 mRNA levels between primary melanocytes and primary cultures of metastatic melanoma. However, immunohistochemistry staining of progression tissue microarray comprised of samples of different disease stages derived from different patients, demonstrated a dramatic ICAM-1 upregulation particularly upon the transition from primary tumor to lymph node metastasis. There was no significant difference between lymph node and distant metastases. Importantly, these results were confirmed in an independent tissue microarray comprised of patient-paired specimens from progressive stages of the patient’s disease. These data indicate that ICAM-1 upregulation is required to initiate the lymphatic spread of melanoma (Stage III) but no further increase is associated with progression to remote organs (Stage IV).

The dual role of tumor lymphatic vessels in dissemination of metastases and immune response development

Lymphatic vasculature plays a crucial role in the immune response, enabling transport of dendritic cells (DCs) and antigens (Ags) into the lymph nodes. Unfortunately, the lymphatic system has also a negative role in the progression of cancer diseases, by facilitating the metastatic spread of many carcinomas to the draining lymph nodes. The lymphatics can promote antitumor immune response as well as tumor tolerance. Here, we review the role of lymphatic endothelial cells (LECs) in tumor progression and immunity and mechanism of action in the newest anti-lymphatic therapies, including photodynamic therapy (PDT).

Cell Adhesion Molecules and Ubiquitination-Functions and Significance

Cell adhesion molecules of the immunoglobulin (Ig) superfamily represent the biggest group of cell adhesion molecules. They have been analyzed since approximately 40 years ago and most of them have been shown to play a role in tumor progression and in the nervous system. All members of the Ig superfamily are intensively posttranslationally modified. However, many aspects of their cellular functions are not yet known. Since a few years ago it is known that some of the Ig superfamily members are modified by ubiquitin. Ubiquitination has classically been described as a proteasomal degradation signal but during the last years it became obvious that it can regulate many other processes including internalization of cell surface molecules and lysosomal sorting. The purpose of this review is to summarize the current knowledge about the ubiquitination of cell adhesion molecules of the Ig superfamily and to discuss its potential physiological roles in tumorigenesis and in the nervous system.

Proposed new lymphology combined with lymphatic physiology, innate immunology, and oncology

As one of the lymphatic functions, it is well known that the transport and drainage of hydrophilic substances including plasma protein through the lymphatic system play pivotal roles in maintaining the homeostasis of the internal environment between the cells in tissues in collaboration with the exchange of the substances through the blood capillaries and venules. The physiological functions of the lymphatic system have been studied by many investigations of microcirculation, i.e., Yoffey and Courtice, Ruszunyak et al., Földie and Casley-Smigh et al., Roddie, Schmid-Schönbein et al., and Ohhashi et al. On the other hand, it is also well known that the initial clinical signs of primary diseases such as inflammation, tumors, and circulatory disorders including infarction and thrombosis appear as functional abnormalities of the internal environment in tissues. These abnormalities of the functions are strongly related to immunological defense reactions around the internal environment and abnormal actions of the transport and drainage of the lymphatic system. Taking into consideration the current inspired findings in lymphatic physiology, innate immunology, and oncology, we have proposed a new lymphology combined with new knowledge of the three above-mentioned academic fields from a defense mechanism points of view. In this review, we would like to demonstrate comprehensively our latest studies related to the possibility of establishing a new lymphology, hoping the readers will evaluate this possibility.

The distinct expression patterns of claudin-10, -14, -17 and E-cadherin between adjacent non-neoplastic tissues and gastric cancer tissues

BACKGROUND

Recent data indicate that the cell adhesion proteins are abnormally regulated in several human cancers and the expression of the cell adhesion proteins E-cadherin and claudin proteins is involved in the etiology and progression of cancer. It is clear that these protein represent promising targets for cancer detection, diagnosis, and therapy.

METHODS

To explore the expression distinction of the cell adhesion proteins claudin-10,-14,-17 and E-cadherin in the adjacent non-neoplastic tissues and gastric cancer tissues, 50 gastric cancer tissues and 50 samples of adjacent non-neoplastic tissues adjacent to the tumors were examined for expression of claudin-10,-14,-17 and E-cadherin by streptavidin-perosidase immunohistochemical staining method.

RESULTS

The positive expression rates of E-cadherin in gastric cancer tissues and adjacent non-neoplastic tissues were 32% and 74% respectively (P < 0.01). The positive expression rates of claudin-10 in gastric cancer tissues and adjacent non-neoplastic tissues were 24% and 72% respectively (P < 0.01). The positive expression rates of claudin-17 in gastric cancer tissues and adjacent non-neoplastic tissues were 18% and 70% (P < 0.01). In contrast, the positive expression rates of claudin-14 in gastric cancer tissues and adjacent non-neoplastic tissues were 58% and 24% respectively (P = 0.015 < 0.05) Thus in our study, the expression of E-cadherin, claudin-10, and claudin-17 was down-regulated in gastric cancer tissue while the expression of claudin-14 was up-regulated. Correlations between claudins and E-cadherin expression with lymphatic metastasis were observed.

CONCLUSION

Our study reveals that the expression of E-cadherin, claudin-10, and claudin-17 were down-regulated in gastric cancer tissue while the expression of claudin-14 was up-regulated and correlation between claudins and E-cadherin expression with lymphatic metastasis were observed.

VIRTUAL SLIDES

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1475928069111326.

CD146, a multi-functional molecule beyond adhesion

CD146 is a cell adhesion molecule (CAM) that is primarily expressed at the intercellular junction of endothelial cells. CD146 was originally identified as a tumor marker for melanoma (MCAM) due to its existence only in melanoma but not in the corresponding normal counterpart. However CD146 is not just a CAM for the inter-cellular and cell-matrix adhesion. Recent evidence indicates that CD146 is actively involved in miscellaneous processes, such as development, signaling transduction, cell migration, mesenchymal stem cells differentiation, angiogenesis and immune response. CD146 has increasingly become an important molecule, especially identified as a novel bio-marker for angiogenesis and for cancer. Here we have reviewed the dynamic research of CD146, particularly newly identified functions and the underlying mechanisms of CD146.

Pivotal roles of shear stress in the microenvironmental changes that occur within sentinel lymph nodes

A sentinel lymph node (SLN) is the first lymph node that receives drainage from a primary tumor. According to their physiological and biomechanical characteristics, we hypothesized that SLN contains lymphatic endothelial cells (LEC) that are constantly loaded with high levels of shear stress, which might contribute to the production of a suitable environment for micrometastasis within them. To test this hypothesis, we investigated the effects of shear stress stimulation on the expression of adhesion molecules on human LEC isolated from the lymph vessels nearest the SLN of breast cancers, and on the release of ATP from human LEC. The study clarified that the shear stress stimulation produced a significant increase of ICAM-1 expression at protein and mRNA levels in human LEC. Next, we examined whether the shear stress-mediated increase of ICAM-1 expression accelerates the attachment of carcinoma cells to human LEC. Finally, in in vivo experiments, we evaluated whether exogenous ATP facilitates the expression of carcinoma cell-ligated adhesion molecules in rat SLN. In conclusion, shear stress stimulation induces ICAM-1 expression on human LEC by activating cell surface F(1) /F(O) ATP synthase, which might contribute to the development of a premetastatic environment within SLN.

Real-time imaging of the lymphatic channels and sentinel lymph nodes of the stomach using contrast-enhanced ultrasonography with Sonazoid in a porcine model

The contrast-enhanced ultrasound (CEUS)-guided method in combination with Sonazoid has not been clinically or experimentally evaluated with regard to its use for identifying sentinel lymph node (SLN) in the stomach. Therefore, we attempted to evaluate the usefulness of the CEUS-guided method with Sonazoid for imaging of the lymphatic channels and SLN of the stomach in a porcine model by comparing it with the conventional Evans blue dye-guided method. Twenty-eight 2 to 3-month-old swine weighing 17-30 kg were used in this experiment. Anesthesia was maintained with 2.0-3.0% isoflurane/O(2) inhalation. Sonazoid was injected into the intra- and sub-mucosal layers of the stomach. The intragastric or transcutaneous CEUS-guided method was used to identify the lymphatic channels and SLN of the stomach. Contrast imaging using the CEUS-guided method with Sonazoid enabled us to produce clear images of the afferent lymph vessel and SLN of the stomach until 2 h after the injection of Sonazoid. In addition, intranodal flow of the microbubble agent could be clearly identified using tissue linear harmonic images of the SLN. The SLN detection rate was not significantly different between the CEUS- and dye-guided methods. However, the Evans blue dye flowed out quickly (≈ 15 min after the injection) through the true SLN into the next LN of stomach. In conclusion, the use of the CEUS-guided method with Sonazoid might be the most useful clinical procedure for producing real-time images of the SLN of the stomach, and the linear harmonic images are also useful for evaluating intranodal structure within the SLN.

Physiopathology of spine metastasis

The metastasis is the spread of cancer from one part of the body to another. Two-thirds of patients with cancer will develop bone metastasis. Breast, prostate and lung cancer are responsible for more than 80% of cases of metastatic bone disease. The spine is the most common site of bone metastasis. A spinal metastasis may cause pain, instability and neurological injuries. The diffusion through Batson venous system is the principal process of spinal metastasis, but the dissemination is possible also through arterial and lymphatic system or by contiguity. Once cancer cells have invaded the bone, they produce growth factors that stimulate osteoblastic or osteolytic activity resulting in bone remodeling with release of other growth factors that lead to a vicious cycle of bone destruction and growth of local tumour.

Identification of NCAM that interacts with the PHE-CoV spike protein

BACKGROUND

The spike proteins of coronaviruses associate with cellular molecules to mediate infection of their target cells. The characterization of cellular proteins required for virus infection is essential for understanding viral life cycles and may provide cellular targets for antiviral therapies.

RESULTS

We identified Neural Cell Adhesion Molecule (NCAM) as a novel interacting partner of the PHE-CoV S protein. A T7 phage display cDNA library from N2a cells was constructed, and the library was screened with the soluble PHE-CoV S glycoproteins. We used a coimmunoprecipitation assay to show that only the NCAM was a binding partner of spike protein. We found that a soluble form of anti-NCAM antibody blocked association of the PHE-CoV with N2a cells. Furthermore, double-stranded siRNA targeted against NCAM inhibited PHE-CoV infection.

CONCLUSIONS

A novel interaction was identified between NCAM and spike protein and this association is critical during PHE-CoV infection.

Molecular interactions in cancer cell metastasis

Metastasis, the process by which cancer cells leave the primary tumour, disseminate and form secondary tumours at anatomically distant sites, is a serious clinical problem as it is disseminated disease, which is often impossible to eradicate successfully, that causes the death of most cancer patients. Metastasis results from a complex molecular cascade comprising many steps, all of which are interconnected through a series of adhesive interactions and invasive processes as well as responses to chemotactic stimuli. In spite of its clinical significance, it remains incompletely understood. This review provides an overview of some of the molecular interactions that are critical to metastasis. It summarises the principle molecular players in the major steps of the metastatic cascade. These are: (1) tumour angiogenesis, (2) disaggregation of tumour cells from the primary tumour mass, mediated by cadherins and catenins, (3) invasion of, and migration through, the basement membrane (BM) and extracellular matrix (ECM) surrounding the tumour epithelium, and subsequent invasion of the BM of the endothelium of local blood vessels. This is mediated through integrins and proteases, including urokinase form of plasminogen activator (uPA), matrix metalloproteinases (MMPs) and cathepsins, (4) intravasation of the tumour cells into the blood vessels prior to hematogeneous dissemination to distant sites, (5) adhesion of the circulating tumour cells to the endothelial cell lining at the capillary bed of the target organ site. This occurs through adhesive interactions between cancer cells and endothelial cells involving selectins, integrins and members of the immunoglobulin superfamily (IgSF), (6) invasion of the tumour cells through the endothelial cell layer and surrounding BM (extravasation) and target organ tissue and (7) the development of secondary tumour foci at the target organ site.

A gene signature of primary tumor identifies metastasized seminoma

BACKGROUND

The aim of this study was the prediction of metastatic status in seminoma based on examination of the primary tumor.

METHODS

Total RNA was isolated from metastasized seminoma (n = 10, T1N1-2M0), non-metastasized seminoma (n = 21, T1-3N0M0), and corresponding normal tissues. Pooled RNA from 10 biopsies of each tissue type was hybridized on whole genome microarrays for screening purposes. Ninety-two selected gene candidates were quantitatively examined using real-time quantitative polymerase chain reaction (RTQ-PCR).

RESULTS

Agreement in gene expression was 88% between the whole genome microarrays and RTQ-PCR. Metastasized seminoma showed 1,912 up-regulated and 2,179 down-regulated genes with ≥ 2-fold differences in gene expression compared non-metastasized seminoma. RTQ-PCR of selected genes showed that mean gene expression values were significantly reduced in metastasized compared with non-metastasized seminoma. The presence of metastases could be predicted based on an 85-gene expression signature by using logistic regression. Sensitivity and accuracy of the 10-fold cross-validation model were 77.8% and 84.2%, respectively.

CONCLUSION

A logistic regression model using an 85 gene expression signature allowed identification of metastasized seminoma from the primary tumor with a sensitivity of 77.8%.

Chemokine CCL2 facilitates ICAM-1-mediated interactions of cancer cells and lymphatic endothelial cells in sentinel lymph nodes

We examined the effects of CCL1, CCL2, CCL12 and CCL21 on the expression of adhesion molecules in cultured human lymphatic endothelial cells using immunohistochemical staining or Western blot analysis. In addition, we investigated whether the expressed adhesion molecule was able to facilitate the attachment of carcinoma cells to the lymphatic endothelial cells as an in vitro micrometastatic model. CCL2 caused a selective and significant expression of ICAM-1 on human lymphatic endothelial cells but CCL1, CCL12 and CCL21 did not. By increasing the stimulation time from 4 to 18 and 48 h, the intensity of immunoreactivity for ICAM-1 was significantly increased in a time-dependent manner up to 18 h. The ICAM-1 mRNA levels were also elevated significantly up to 18 h. The CCL2-mediated immunohistochemical expression of ICAM-1 was dose-dependently increased from 10 pg/mL to 1 ng/mL. The CCL2-mediated expression of ICAM-1 was significantly reduced by neutralization of CCL2 using a specific CCL2 antibody. The 18-h treatment with CCL2 caused a significant facilitation of in vitro attachment of MDA-MB-231 and MCF-7 cells to the lymphatic endothelial cells (LECs). The CCL2-mediated response in the attachment assay was also significantly reduced either by the neutralization of CCL2 or by additional treatment with anti-ICAM-1 antibody. Immunohistochemical expression of ICAM-1, but not E-selectin, was strongly observed around and within the metastatic region of sentinel lymph node isolated from breast cancer patients. These findings suggest that CCL2 induces selective and significant expression of ICAM-1 on cultured human lymphatic endothelial cells and then facilitates the attachment of carcinoma cells to the lymphatic endothelial cells, thus providing an in vitro micrometastatic model via the overexpression of ICAM-1.

MDA-MB-231 produces ATP-mediated ICAM-1-dependent facilitation of the attachment of carcinoma cells to human lymphatic endothelial cells

We examined the effects of supernatants of culture media of MDA-MB-231 and MCF-7 cells on the expression of adhesion molecules on human lymphatic endothelial cells (LECs) and evaluated whether the overexpression of adhesion molecules facilitated the attachment of carcinoma cells to LECs. The 48-h stimulation of MDA-MB-231, but not MCF-7, supernatant produced a significant expression of ICAM-1 on human LECs but little or no expression of E-selectin. Chemical treatment with dialyzed substances of <1,000 molecular weight (MW) caused a complete reduction of the supernatant-mediated response. In contrast, pretreatment with heating, digestion with protease, or chemical treatment with dialyzed substances of <500 MW produced no significant effect on the supernatant-mediated response. ATP (10(-7) M) caused overexpression of ICAM-1 on human LECs similar to that produced by the supernatant of MDA-MB-231. The ATP- and MDA-MB-231 supernatant-mediated responses were significantly reduced by treatment with 10(-6) M suramin (a purinergic P2X and P2Y receptor antagonist). In attachment assays, 10(-7) M ATP or MDA-MB-231 supernatant produced a significant increase in the attachment of carcinoma cells to human LECs. The treatment with 10(-6) M suramin caused a significant reduction of ATP- and supernatant-mediated facilitation of the attachment responses. Additional treatment with anti-ICAM-1 antibody also caused a significant reduction of ATP- and supernatant-mediated facilitation of the attachment responses. The experimental findings suggest that MDA-MB-231 may release or leak ATP, which produces the overexpression of ICAM-1 on human LECs through activation of purinergic P2X and/or P2Y receptors and then facilitates ICAM-1-mediated attachment of carcinoma cells to LECs.

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.

DNA tumour viruses promote tumour cell invasion and metastasis by deregulating the normal processes of cell adhesion and motility

Approximately 15-20% of global cancer incidence is causally linked to viral infection, yet the low incidence of cancers in healthy infected individuals suggests that malignant conversion of virus-infected cells occurs after a long period as a result of additional genetic modifications. There are four families of viruses that are now documented to be involved in the development of human cancers which include members of the polyomavirus, hepadnavirus, papillomavirus and herpesvirus families. Although a number of these viruses are implicated in the aetiology of lymphomas or leukaemias, the vast majority are associated with malignancies of epithelial cells. In epithelial tissues, several classes of proteins are involved in maintaining tissue architecture, including those that promote cell-cell adhesion, and others, which mediate cell-matrix interactions. Proteins representative of all classes are frequently altered in malignant tumour cells that possess invasive and metastatic properties. Malignant tumour cells acquire mechanisms to degrade basement membranes and invade the underlying tissue. Many viruses encode proteins which engage signalling pathways that affect one or more of these mechanisms. It is believed that activation of these processes by chronic viral infection can, under certain circumstances, promote tumour cell invasion and metastasis. This review will take a brief look at the current knowledge of viral-induced alterations in cell motility and invasiveness in the context of tumour invasion and metastasis.

Early metastasis of human solid tumours: expression of cell adhesion molecules

Loss and gain of cell surface molecules determines the mobilization, emigration and invasiveness of epithelial cancer cells. As a first approach to gain further insight into these processes, we have followed two strategies: (1) to identify tumour cells which have disseminated early from primary carcinomas and to obtain information about the phenotype and prognostic significance of these cells; and (2) to identify molecular changes occurring in primary tumour cells at the time they develop their metastatic potential. Our analyses indicate that changes in the adhesive properties of solid tumour cells, such as down-regulation of desmosomal proteins (e.g. plakoglobin) and neo-expression of ICAM-1 or MUC18, are important determinants of the metastatic capability of individual malignant cells. The expression pattern of these cell adhesion molecules during tumour progression appears to reflect a disturbance at the level of the molecular elements normally responsible for controlling their expression. The outlined current strategies for detection, characterization and antibody therapy of cancer micrometastasis can be applied to the secondary prevention of metastatic disease in patients with minimal residual cancer.

Cell Cycle Genes PEDF and CDKN1C in Growing Deer Antlers

Deer antlers are the only mammalian appendage to display an annual cycle of full regeneration. The growth phase in antler involves the rapid proliferation of several tissues types, including epidermis, dermis, cartilage, bone, blood vessels, and nerves. Antlers thus provide an excellent model to study the developmental regulation of these tissues. We describe here the identification of two genes, pigment epithelium-derived factor (PEDF) and cyclin-dependent kinase inhibitor 1C (CDKN1C), both of which are known to be involved in cell proliferation and differentiation. These genes were identified as the result of screening an expressed sequence tag database derived from a cDNA library enriched for sequences from the growing antler tip. PEDF mRNA was detected in developing skin, cartilage, and bone during endochondral ossification. PEDF mRNA was not detected within endothelial cells that exhibited positive immunoreactivity to a CD146 antibody. CDKN1C mRNA was expressed by only the immature chondrocytes within the precartilage region. These results suggested that PEDF and CDKN1C are important genes involved in cell proliferation and differentiation during antler growth.

Heterogeneous Metastasis Efficiency of Isogenic Orthotopic Colon Cancer Xenografts Reveals Distinctive Gene Expression Profiles

Hepatic and lung metastases are the leading causes of mortality and major indicators of aggressiveness in colorectal cancer. The underlying molecular mechanisms contributing to the development of metastasis are still unclear. Here, we designed a novel approach to explore gene expression profiles associated with metastasis in human colorectal cancer (hCRC). A series of ten isogenic tumors from three different hCRC models were orthotopically implanted into nude mice. In these series, we analyzed the contribution of dynamic heterogeneity, independently of any intrinsic gene expression program predictive of metastasis. When screened for the presence of disseminated tumor cells in the lung and liver, as the most common host tissues for hCRC metastases, both high- and low-metastatic efficient tumors were found among these isogenic orthotopic series. The metastasis-specific cDNA macroarray analysis of 96 genes, in both tumor populations for each of the three hCRC models, characterized a common differential gene expression within a small group of genes. Our results suggest that, independently of a gene expression profile predictive of metastasis, the progressive acquisition of additional alterations occurs during hCRC tumorigenesis. This dynamic process might determine tumor progression, namely the metastasis dissemination.

Cancer: novel therapeutic strategies that exploit the TNF-related apoptosis-inducing ligand (TRAIL)/TRAIL receptor pathway

Cancer is a widespread disease, with half of all men and one-third of all women in the United States developing cancer during their lifetime. The efficacy of many cancer treatments including radiotherapy, chemotherapy and immunotherapy is due to their ability to induce tumor cell apoptosis. Recombinant tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is currently being developed as a cancer therapeutic since it selectively induces apoptosis in a variety of transformed cells, but not in most normal cells. Agonistic monoclonal antibodies (mAbs) specific for human death-inducing TRAIL receptors (DR4 or DR5) are also being actively pursued. Importantly, in experimental mice, synergistic anti-tumor effects have been observed with a combination treatment of agonistic mAb against DR5 together with either IL-21 or agonistic mAbs against CD40 and CD137. Together, these findings suggest that antibody-based therapies that cause tumor cell apoptosis and promote T cell memory or function may be effective in fighting cancer.

Gene expression signatures and biomarkers of noninvasive and invasive breast cancer cells: comprehensive profiles by representational difference analysis, microarrays and proteomics

We have characterized comprehensive transcript and proteomic profiles of cell lines corresponding to normal breast (MCF10A), noninvasive breast cancer (MCF7) and invasive breast cancer (MDA-MB-231). The transcript profiles were first analysed by a modified protocol for representational difference analysis (RDA) of cDNAs between MCF7 and MDA-MB-231 cells. The majority of genes identified by RDA showed nearly complete concordance with microarray results, and also led to the identification of some differentially expressed genes such as lysyl oxidase, copper transporter ATP7A, EphB6, RUNX2 and a variant of RUNX2. The altered transcripts identified by microarray analysis were involved in cell-cell or cell-matrix interaction, Rho signaling, calcium homeostasis and copper-binding/sensitive activities. A set of nine genes that included GPCR11, cadherin 11, annexin A1, vimentin, lactate dehydrogenase B (upregulated in MDA-MB-231) and GREB1, S100A8, amyloid beta precursor protein, claudin 3 and cadherin 1 (downregulated in MDA-MB-231) were sufficient to distinguish MDA-MB-231 from MCF7 cells. The downregulation of a set of transcripts for proteins involved in cell-cell interaction indicated these transcripts as potential markers for invasiveness that can be detected by methylation-specific PCR. The proteomic profiles indicated altered abundance of fewer proteins as compared to transcript profiles. Antisense knockdown of selected transcripts led to inhibition of cell proliferation that was accompanied by altered proteomic profiles. The proteomic profiles of antisense transfectants suggest the involvement of peptidyl-prolyl isomerase, Raf kinase inhibitor and 80 kDa protein kinase C substrate in mediating the inhibition of cell proliferation.

Pathogenesis of bone metastasis: a review

BACKGROUND

Metastasic deposits from malignancies frequently lodge in the skeleton, including the jaw bones.

METHOD

A review of the literature was performed in order to provide a coherent overview on the pathogenesis of bone metastasis.

RESULTS

Bone metastasis follows complex molecular interactions that enable tumor cells to detach from the primary site, invade the extracellular matrix, intra-vasate, extra-vasate, and proliferate within bone. They induce local bone changes that could manifest radiologically as either osteolytic or radiodense. In addition to the direct bone changes, malignancies can elaborate mediators that are released in circulation, leading to generalized osteopenia.

CONCLUSIONS

The spread of malignant neoplasms to bone is not a random process but rather a cascade of specific molecular events orchestrated through complex interactions between neoplastic cells and their environment.

Inhibition of B16 Melanoma Metastases with the Ruthenium Complex Imidazoliumtrans-Imidazoledimethylsulfoxide-tetrachlororuthenate and Down-Regulation of Tumor Cell Invasion

The antimetastatic ruthenium complex imidazolium trans-imidazoledimethylsulfoxide-tetrachlorouthenate (NAMI-A) is tested in the B16 melanoma model in vitro and in vivo. Treatment of B6D2F1 mice carrying intra-footpad B16 melanoma with 35 mg/kg/day NAMI-A for 6 days reduces metastasis weight independently of whether NAMI-A is given before or after surgical removal of the primary tumor. Metastasis reduction is unrelated to NAMI-A concentration, which is 10-fold lower than on primary site (1 versus 0.1 mM), and is correlated to the reduction of plasma gelatinolitic activity and to the decrease of cells expressing CD44, CD54, and integrin-beta(3) adhesion molecules. Metastatic cells also show the reduction of the S-phase cells with accumulation in the G(0)/G(1) phase. In vitro, on the highly metastatic B16F10 cell line, NAMI-A reduces cell Matrigel invasion and its ability to cross a layer of endothelial cells after short exposure (1 h) to 1 to 100 microM concentrations. In these conditions, NAMI-A reduces the gelatinase activity of tumor cells, and it also increases cell adhesion to poly-L-lysine and, in particular, to fibronectin, and this effect is associated to the increase of F-actin condensation. This work shows the selective effectiveness of NAMI-A on the metastatic melanoma and suggests that metastasis inhibition is due to the negative modulation of tumor cell invasion processes, a mechanism in which the reduction of the gelatinolitic activity of tumor cells plays a crucial role.

A relação da caderina-E com o prognóstico do adenocarcinoma colorretal

OBJETIVO: Avaliar a relação da expressão da caderina-E com o intervalo livre de doença (ILD), com a sobrevida (S) e com o estadiamento de doentes operados por adenocarcinoma colorretal. MÉTODO: Foram estudados 89 doentes (41 homens e 48 mulheres) com média de idade de 62,3 anos. A distribuição segundo o estadiamento TNM foi: estádio I - 13 (14,6%) doentes, estádio II - 29 (32,6%), estádio III - 23 (25,8%) e estádio IV - 24 (27,0%). Sessenta e sete doentes foram submetidos à operação radical e acompanhados por um período médio de 37,9 meses. Os tumores foram examinados por técnica imuno-histoquímica e classificados como positivos ou negativos em relação à expressão da caderina-E. RESULTADOS: A caderina-E foi positiva em 49,4% e negativa em 50,6% dos doentes. A recidiva ocorreu em 22,4% dos doentes e não esteve relacionada à expressão da caderina-E. Não foi observada relação da caderina- E com intervalo livre de doença e com a sobrevida. Também não foi verificada a associação da caderina-E (p = 0,958) com o estadiamento TNM. CONCLUSÃO: Os resultados verificados nesta pesquisa não permitem relacionar a expressão tissular da caderina-E com o estadiamento e o prognóstico do adenocarcinoma colorretal.

HPA binding and metastasis formation of human breast cancer cell lines transplanted into severe combined immunodeficient (scid) mice

Six human breast cancer cell lines were injected subcutaneously into scid mice and their in vivo growth behaviour and HPA binding pattern were analysed. Furthermore, the role of HPA binding glycoconjugates concerning the adhesion to endothelial cells in vitro was investigated. Four of the tested cell lines engrafted in the scid mouse model but they showed considerable variations concerning their growth behaviour, their metastatic potential and their HPA binding pattern. HPA inhibited adhesive interactions between cell lines derived from metatstatic sources and tumour necrosis factor (TNF)alpha stimulated endothelial cells. The transplantation of HPA defined breast cancer cell lines into scid mice is a useful animal model for the research of breast cancer and its metastasis. The HPA binding glycoconjugates appear to be associated with adhesive interactions between metastasising tumour cells and endothelial cells.

Multitasking in tumor progression: signaling functions of cell adhesion molecules

Approximately 90% of all cancer deaths arise from metastasis formation. Hence, understanding the molecular mechanisms underlying tumor progression, local invasion, and the formation of tumor metastases represents one of the great challenges in exploratory cancer research. Recent experimental results indicate that changes in cell adhesion play a critical role in tumor progression. Cell adhesion molecules of varying classes and functions, including cadherins, cell adhesion molecules of the immunoglobulin family (Ig-CAMs), CD44, and integrins, can interact with and modulate the signaling function of receptor tyrosine kinases (RTKs). Conversely, signaling by RTKs can directly affect the adhesive function of adhesion molecules. Loss of E-cadherin and gain of mesenchymal cadherin function as well as changes in the expression of Ig-CAMs during the progression of many cancer types exemplify such functional implicatons: cell adhesion molecules not only define a tumor cell's adhesive repertoire, but also directly influence classic signal transduction pathways, thereby modulating the metastatic behavior of tumor cells.

The molecular basis of skeletal metastases

Metastasis is the culmination of numerous highly regulated sequences of steps that results in the proliferation and migration of cells from the primary site to a distant location. The biologic consequence of skeletal metastasis is focal bone sclerosis or osteolysis that leads to pain, pathologic fracture, and biochemical derangement. The difficulty in determining a point of control for clinical application has been because of the numerous systems, substrates, ligands, receptors, factors, and pathways that exist. These may be grouped into functional mechanisms identifiable by their relevance to the metastatic process. These include cell-cell or cell-matrix adhesion, invasion and migration, interactions with endothelial cells, growth factor regulation, proteolysis, and stimulation of differentiated osteoblast and osteoclast function. The challenge for cancer therapy will be to identify means to prevent metastasis or reduce its effect once it occurred. This review examines recent advances in the study of molecular processes of metastasis, which have identified potential sites and substrates for targeting with novel therapies and agents.

Human herpesvirus-8 and Kaposi's sarcoma: relationship with the multistep concept of tumorigenesis

Kaposi's sarcoma (KS) develops through discrete inflammatory-angiogenic stages of polyclonal nature (early-stage lesions) to monomorphic nodules of spindle-shaped cells that can be clonal (late-stage lesions) and resemble true sarcomas. Molecular and epidemiological studies indicate that development of KS is tightly associated with infection by the human herpesvirus-8 (HHV-8). However, only individuals with specific conditions of immunodysregulation develop KS. In these individuals the systemic and tissue increase of Th-1-type cytokines (IC) reactivate HHV-8 infection, leading to increased viral load, antibody titers, and an expanded cell tropism that precedes the clinical appearance of KS. Recruitment of the virus into tissues by infected monocytes and other cell types is facilitated by the endothelial cell activation due to IC. In clinical lesions, HHV-8 infection increases with lesion stage and in late-stage lesions most of the spindle cells are latently infected, whereas only few lyrically infected cells are present, suggesting that latent genes may have a role in the transformation of the early inflammatory-hyperplastic lesion into a real sarcoma. The development of tumors, however, is regulated through a multistep process based on the acquisition by cells of several different capabilities leading to malignant growth. Here we review the available data on the expression of HHV-8-encoded genes in primary KS lesions and, in view of their biological activity, analyze their potential function in different steps of tumorigenesis. By this pragmatic approach interesting insights into potential key functions of HHV-8-encoded genes are found and steps of potential cooperativity with other viral factors (HIV-1-Tat) in the pathogenesis of KS are identified.

Cell adhesion in tumor invasion and metastasis: loss of the glue is not enough

Tumor cells often show a decrease in cell-cell and/or cell-matrix adhesion. An increasing body of evidence indicates that this reduction in cell adhesion correlates with tumor invasion and metastasis. Two main groups of adhesion molecules, cadherins and CAMs, have been implicated in tumor malignancy. However, the specific role that these proteins play in the context of tumor progression remains to be elucidated. In this review, we discuss recent data pointing to a causal relationship between the loss of cell adhesion molecules and tumor progression. In addition, the direct involvement of these molecules in specific signal transduction pathways will be considered, with particular emphasis on the alterations of such pathways in transformed cells. Finally, we review recent observations on the molecular mechanisms underlying metastatic dissemination. In many cases, spreading of tumor cells from the primary site to distant organs has been characterized as an active process involving the loss of cell-cell adhesion and gain of invasive properties. On the other hand, various examples of metastases exhibiting a relatively benign (i.e. not invasive) phenotype have been reported. Together with our recent results on a mouse tumor model, these findings indicate that 'passive' metastatic dissemination can occur, in particular as a consequence of impaired cell-matrix adhesion and of tumor tissue disaggregation.

Reduced expression of intercellular adhesion molecule-1 in ovarian adenocarcinomas

Ovarian adenocarcinomas develop as the result of multiple genetic and epigenetic changes in the precursor ovarian surface epithelial (OSE) cells which result in a malignant phenotype. We investigated changes in gene expression in ovarian adenocarcinoma using a cDNA array containing 588 known human genes. We found that intercellular adhesion molecule-1 (ICAM-1) was expressed at lower levels in the ovarian tumour cell lines OAW42, PEO1 and JAM than in the immortalised human ovarian surface epithelial cell line HOSE 17.1. Further investigation revealed ICAM-1 was expressed in the surface epithelium of normal ovaries and both mRNA and protein expression levels were reduced in the majority of ovarian adenocarcinoma cell lines and primary tumours. ICAM-1 expression was increased in 8/8 cell lines treated with the de novo methyltransferase inhibitor 5-aza-2'-deoxycytidine, indicating that methylation of CpG islands may play a role in the down-regulation of its expression in primary tumours. There was a significant association between patients whose tumours expressed ICAM-1 and survival (P = 0.03), suggesting that expression levels of ICAM-1 may have clinical relevance.

The selectin superfamily: the role of selectin adhesion molecules in delayed cerebral ischaemia after aneurysmal subarachnoid haemorrhage

Cerebral ischaemia and reperfusion injury may be exacerbated by leukocyte recruitment and activation. Adhesion molecules play a pivotal role in leukocyte recruitment. We report a prospective study of the potential role of the selectin family of adhesion molecules (E-, P- and L-selectin) in delayed cerebral ischaemia (DID) following aneurysmal subarachnoid haemorrhage. In patients with good grade SAH, we have compared serum concentrations of E-, P- and L-selectin, between patients who do, and do not develop delayed cerebral ischaemia. There was no difference in E-selectin concentration between the two groups (44.0 ng/ml vs. 37.4 ng/ml). Serum P-selectin concentration was significantly higher in patients with DID compared to those patients without DID (149.5 ng/ml vs. 112.9 ng/ml, p = 0.039). Serum L-selectin concentrations were significantly lower in patients with DID (633.8 ng/ml vs 897.9 ng/ml, p = 0.013). We conclude that P- and L-selectin are involved in the pathogenesis of DID following aneurysmal subarachnoid haemorrhage. The results of this study do not elucidate the exact role of each selectin in DID.

N-CAM modulates tumour-cell adhesion to matrix by inducing FGF-receptor signalling

Loss of expression of neural cell-adhesion molecule (N-CAM) is implicated in the progression of tumour metastasis. Here we show that N-CAM modulates neurite outgrowth and matrix adhesion of beta-cells from pancreatic tumours by assembling a fibroblast-growth-factor receptor-4 (FGFR-4) signalling complex, which consists of N-cadherin, FGFR-4, phospholipase C gamma (PLC-gamma), the adaptor protein FRS2, pp60(c-src), cortactin and growth-associated protein-43 (GAP-43). Dominant-negative FGFR-4, inhibitors of FGFR signalling and anti-beta(1)-integrin antibodies repress matrix adhesion induced by N-CAM. FGF ligands can replace N-CAM in promoting matrix adhesion but not neurite outgrowth. The results indicate that N-CAM stimulates beta1-integrin-mediated cell-matrix adhesion by activating FGFR signalling. This is a potential mechanism for preventing the dissemination of metastatic tumour cells.

Expression of neural cell adhesion molecules (polysialylated form of neural cell adhesion molecule and L1-cell adhesion molecule) on resected small cell lung cancer specimens: in relation to proliferation state

BACKGROUND AND OBJECTIVES

Alteration of homotypic cell-cell adhesion has been suggested to play an important role in tumor progression. The present study examined the relationship between neural cell adhesion molecules and state of proliferation of small cell lung cancer (SCLC) cells.

METHODS

Seventeen surgically resected specimens of SCLC were immunohistochemically examined, by using monoclonal antibodies against neural cell adhesion molecule (NCAM) and its polysialic acid side chains, and L1 cell adhesion molecule (L1-CAM). Ki-67 labeling indices were also determined immunohistochemically.

RESULTS

All patients were positive for L1-CAM. Fifteen patients (88.2%) were positive for NCAM. Among the fifteen patients, nine (60.0%) were positive for NCAM PSA side chain. The probability of survival of the NCAM without PSA side chain group was significantly higher than that of the NCAM with PSA side chain group (log-rank test; P = 0.500).

CONCLUSIONS

The expression of NCAM with PSA side chains might be a prognostic factor and NCAM a marker for SCLC. L1-CAM may be synthesized independent of state of proliferation of individual tumor cell and may affect clinical feature of SCLC.