Cell Adhesion Molecule E-cadherin Research Articles

Cadherins and the tumour progression: is it all in a switch?

Progression to tumour malignancy involves changes in a tumour cell's capabilities to adhere and communicate with neighboring cells and with its extracellular environment. Correlation studies in human cancer specimen and functional experiments with cultured tumour cells and transgenic mouse models have indicated that the loss of the cell adhesion molecule E-cadherin is causally involved in the formation of epithelial cancers (carcinomas). More recently, it has been observed that the function of E-cadherin is replaced or overruled by the expression of mesenchymal cadherins, such as N-cadherin. Although the functional implication of such a ‘cadherin switch’ remains to be elucidated, recent experimental results demonstrating an interaction of cadherins with tyrosine kinase receptors suggest that changes in cadherin expression may not only modulate tumour cell adhesion but also affect signal transduction and, hence, the malignant phenotype.

Expression of E-Cadherin and α-, β-, γ-Catenin Proteins in Endometrial Carcinoma

Loss of the cell adhesion molecule E-cadherin is suggested to promote tumor invasion and distant metastasis in tumor development. Recently, it has been proposed that E-cadherin function requires its linkage to the cytoskeleton through catenins. We evaluated the expression of E-cadherin and alpha-, beta-, gamma-catenins in tissues of human endometrial carcinoma, analyzed the patterns of cell adhesion molecules' expression in endometrial carcinoma and investigated the relationship between the statuses of cell adhesion molecules and various clinicopathological factors. This study investigated the immunohistochemical expression of E-cadherin and alpha-, beta-, gamma-catenins in 33 paraffin embedded formalin fixed tissues of endometrial carcinomas. Aberrant E-cadherin, and alpha-, beta-, gamma-catenin expression was observed in 33.3 (11 of 33), 27.3 (9 of 33), 18.2 (6 of 33), and 51.5 (17 of 33) % of the specimens, respectively. Statistically significant correlation was found between aberrant expression of E-cadherin and lymph node metastasis and cell types other than endometrioid adenocarcinoma. Aberrant pattern of gamma-catenin expression was also correlated with deep myometrial invasion. However, alpha-, and beta-catenin expression was not correlated with any clinicopathological parameters. Using the Kaplan-Meier method and log-rank comparison test, abnormal expression of E-cadherin was correlated closely with poor survival (p < 0.05), but cases with loss of both E-cadherin and catenin expression predicted even poorer survival than cases with only one or no aberrant expression in E-cadherin and catenins. We revealed aberrant expression of these cell adhesion molecules among patients with endometrial carcinoma. Aberrant expression of E-cadherin was correlated with lymph node metastasis and cell types other than endometrioid adenocarcinoma, while aberrant expression of gamma-catenin was related with deep myometrial invasion. The expression of E-cadherin might be a possible prognostic factor for endometrial cancer while the expression of catenins may help predict patient's survival.

Expression of E-cadherin-catenin complex in human benign schwannomas.

The Ca2+-dependent cell adhesion molecule E-cadherin has been known to express in normal and reactive Schwann cells in rodents, and to play an important role in Schwann cell-Schwann cell adhesion and maintenance of peripheral nervous tissue architecture. However, little is known about expression of E-cadherin in schwannomas. The aim of the present study was to investigate the cellular expression and localization of E-cadherin, and its associated protein, alpha E-, alpha N- and beta-catenins in human schwannomas, which are supposed to derive from Schwann cells. We tested the hypothesis that these proteins might show an altered expression/distribution in schwannoma cells which correlates with their neoplastic behavior, including sparse cell-cell contact, as seen those in meningiomas and various carcinomas. In human schwannomas, however, E-cadherin, alpha E-catenin, and beta-catenin were detected by western blotting and immunohistochemistry, whereas alpha N-catenin was not. Immunoprecipitation using anti-E-cadherin antibody resulted in alpha E-catenin forming a complex with E-cadherin. SSCP analysis revealed no mutations in the transmembrane domain or in intracellular catenin-binding site of E-cadherin. These data suggest that the E-cadherin-alpha E-catenin complex is well preserved in human schwannoma cells, which is compatible with its benign behavior, and these molecules might be used as additional cell markers of Schwann cell-derived tumors.

Single amino acid substitutions in conserved extracellular domains of E-cadherin differ in their functional consequences

The calcium-dependent homophilic cell adhesion molecule E-cadherin typically connects epithelial cells. The extracellular portion of the mature transmembrane protein consists of five homologous domains. The four sequences linking these domains contain the structural amino acid motif DXXD that is thought to be involved in direct calcium binding. In gastric cancer patients mutations affecting this motif between the second and third domain are frequently seen. In order to determine the functional significance of similar sequence alterations with regard to their location, we analyzed single amino acid substitutions changing the DXXD motif to DXXA in each linker region according to a mutation found in gastric cancer (D370A). The cDNA sequences coding for DQND, DVLD and DVND were changed (D257A, D479A, D590A, respectively) and stably expressed in E-cadherin negative MDA-MB-435S mammary carcinoma cells. We found that the D257A and D370A mutations result in abnormal protein localization, changes in the actin cytoskeleton, markedly reduced homophilic cell adhesion, and altered cell morphology. Unexpectetly, the tumor-associated D370A mutation but not the D257A mutation induced increased cell motility. The D479A mutation only had slight functional consequences whereas cells expressing the D590A mutant did not differ from cells expressing the wild-type molecule. Although the putative calcium binding motif DXXD is located at repetitive positions in the extracellular portion of E-cadherin, our results indicate that it has different functions depending on the location. Remarkably, tumor cells select for mutations in the most critical domains resulting both in loss of function (decreased cell adhesion) and in gain of function (increased cell motility). Since multiple DXXD motifs are typically seen in other cadherins, our structure-function study is relevant for this gene family in general.

Inactivation of the E-Cadherin Gene in Sporadic Diffuse-Type Gastric Cancer

Loss of the cell adhesion molecule E-cadherin has been observed in a variety of human carcinomas, and germline E-cadherin mutations have been found in several familial cases of diffuse gastric cancer. We sought to determine the prevalence and nature of E-cadherin alterations in “sporadic” gastric carcinomas. We performed comprehensive sequencing of the coding region, loss of heterozygosity (LOH) analysis, and immunohistochemical protein expression determination on 40 sporadic gastric adenocarcinomas. In total, 7 of 25 diffuse-type cancers harbored genetic alterations in the E-cadherin gene. Novel mutations predicted to significantly compromise protein function were found within 4 of these cancers, 2 of which harbored alterations resulting in biallelic inactivation of the gene product. Three diffuse cancers failed to amplify Exon 8 of E-cadherin, suggesting the presence of a homozygous abnormality. Notably, one germline E-cadherin mutation was also identified within these “sporadic” diffuse cancers. Significant gene mutations were not found in the 14 intestinal-type or histologically mixed cancer. Immunohistochemistry revealed aberrant or negative protein expression in seven diffuse-type tumors, four of which correlated with the genetic alterations. Both diffuse and intestinal-type tumors exhibited low rates of LOH, suggesting that allelic loss at the locus is not a common mechanism for E-cadherin inactivation during gastric tumorigenesis. Our observations suggest that inactivation of the E-cadherin gene occurs only in a subset of diffuse-type gastric cancers, as the majority of cases did not contain genetic alterations or identifiable protein abnormalities. Germline E-cadherin alterations, although rare, may underlie some diffuse gastric cancer cases that have important biologic and practical implications

Mutant cell surface receptors as targets for individualized cancer diagnosis and therapy.

The catalogue of gene alterations in human cancer is growing rapidly. Alterations in specific genes that play important roles in diverse cellular functions such as cell adhesion, signal transduction, differentiation, development or DNA-repair have been identified. Cancer-associated mutant cell surface molecules are very attractive candidates to target tumor cells because they offer the possibility of minimizing toxic effects to non-tumor cells. The cell adhesion molecule E-cadherin has been shown to play a major role in determining which of the two subtypes of gastric cancer, diffuse or intestinal type, develops. E-cadherin gene mutations typically affect the extracellular portion of the homophilic receptor and are frequently found in patients with diffuse-type tumors. Cancer-specific monoclonal antibodies against the E-cadherin mutational hot spot region are now available. In cell culture and in animal studies we have shown that mutation-specific antibodies exclusively target cells expressing abnormal E-cadherin. Those cells expressing the normal protein were not affected, demonstrating the specificity of our approach. After linking to toxins, drugs or radiolabeled mutation-specific antibodies could serve as very specific agents to treat small tumor deposits. Patients for this novel individualized cancer therapy can be identified within a day using routine immunohistochemistry of biopsies.

Clinical significance of E-cadherin-catenin complex expression in metastatic foci of colorectal carcinoma.

Reduced expressions of cell adhesion molecules (E-cadherin, alpha-catenin, and beta-catenin) has been reported to be associated with tumor metastasis. However, the clinical significance of such adhesion molecules in the metastatic foci remains unclear. In this study, we evaluated the prognostic significance of E-cadherin, alpha-catenin, and beta-catenin expressions in the metastatic foci of patients with colorectal carcinoma. The expressions of E-cadherin, alpha-catenin, and beta-catenin were detected immunohistochemically in 105 primary tumors, in 30 metastatic lymph nodes, and 13 metastatic liver tumors from consecutive patients with colorectal carcinoma. Reduced normal expression of E-cadherin, alpha-catenin, and beta-catenin in comparison with normal epithelium was detected in 78 primary tumors, respectively. Patients who had tumors with reduced expression of adhesion molecules showed unfavorable prognosis and the reduced expression of adhesion molecules was detected as one of the independent prognostic factors for patients with colorectal carcinoma. In 30 patients with lymph node metastasis, the increased expression of adhesion molecules in metastatic lymph nodes compared with primary tumors was detected in 13 patients. The prognosis of these 13 patients was poorer than that of remaining 17 patients (P = 0.0296). Also, in 13 patients with liver metastasis, even no significant difference was observed, the mean survival time of 6 patients who had metastatic liver tumors with increased expression of adhesion molecules (10 months) was shorter than that of the remaining 7 patients (16 months; P = 0.1718). These results suggest that increased expression of the cadherin-catenin cell-cell adhesion system in metastatic foci may play an important role in progression of metastatic colorectal carcinomas.

A novel isoform of human lymphoid enhancer-binding factor-1 (LEF-1) gene transcript encodes a protein devoid of HMG domain and nuclear localization signal.

Lymphoid enhancer-binding factor-1 (LEF-1), a member of the high mobility group (HMG) family of proteins, regulates expression of T-cell receptor-alpha gene and is one of the key regulatory molecules in the epithelial-mesenchymal interactions during embryonic development. Among others, LEF-1 regulates expression of cytokeratin genes involved in formation of hair follicles and the gene encoding the cell-adhesion molecule E-cadherin. Transcription factor LEF-1, which acts as a dimer, binds beta-catenin and is involved in signal transduction by the wnt pathway. We have cloned and sequenced a novel isoform of human LEF-1 gene transcript. This isoform encodes a truncated protein devoid of HMG domain and nuclear localization signal but retaining beta-catenin binding domain. This isoform might either act in a dominant-negative manner by interfering with native LEF-1, or might bind beta-catenin in the cytosol, which would result in attenuation of the signals transmitted by the LEF-beta-catenin pathway.

Gastric adenocarcinoma: pathomorphology and molecular pathology.

Two types of gastric adenocarcinoma can be distinguished histopathologically: the diffuse and the intestinal type. Molecular pathology supports this theory by showing differences in the genetic pathways of both tumor types. In addition to known pathomorphological factors of prognosis, e.g., depth of tumor infiltration, number of lymph node metastases and resection margins, a few genes have been suggested to have prognostic impact in gastric carcinoma. Clinically relevant molecules whose expression or structure is altered include the plasminogen activator (uPA) and its inhibitor PAI-1 (plasminogen activator inhibitor type 1), the cell cycle regulator cyclin E, epidermal growth factor (EGF), the apoptosis inhibitor bcl-2, the cell adhesion molecule E-cadherin, and the multifunctional protein beta-catenin. Gene amplification and protein overexpression of the growth factor receptors c-erbB-2 and K-sam may be prognostic factors for intestinal-type and diffuse-type gastric cancer, respectively. In addition, genetic instability is commonly seen. There has long been evidence for a genetic predisposition to gastric cancer by epidemiological studies and case reports. Very recently, germ line mutations of E-cadherin have been identified that are responsible for a dominantly inherited form of diffuse-type gastric cancer and could be used to identify individuals that are at high risk.

Expression of E-cadherin and β-catenin in primary and peritoneal metastatic ovarian carcinoma

Protein expression levels of E-cadherin and beta-catenin were examined in 39 primary and 10 metastatic ovarian carcinoma to elucidate the role of these molecules in the extension of ovarian carcinoma by immunohistochemistry. Twenty-two of 39 (56%) ovarian carcinomas were preserved type and 17 of 39 (44%) were reduced type of E-cadherin. In contrast, 36 of 39 (92%) ovarian carcinomas were preserved type and 3 of 39 (8%) were reduced type of beta-catenin. E-cadherin expression in well-differentiated carcinoma was higher than that in moderately/poorly-differentiated carcinoma (p<0.05). Interestingly, 6 of 10 (60%) peritoneal metastatic lesions resulted in the reduced expression of E-cadherin compared with primary lesions. In contrast, only 2 of 10 (20%) metastatic lesions showed reduced expression of beta-catenin compared with primary lesions. Mutation of exon 3 of beta-catenin gene was rare (3%, 1/39) in carcinoma. These results suggested that the cell adhesion molecule E-cadherin might play an important role in the formation of peritoneal metastasis. In contrast, beta-catenin is not a good indicator of metastasis in human ovarian carcinoma.

Na,K-ATPase beta-subunit is required for epithelial polarization, suppression of invasion, and cell motility.

The cell adhesion molecule E-cadherin has been implicated in maintaining the polarized phenotype of epithelial cells and suppression of invasiveness and motility of carcinoma cells. Na,K-ATPase, consisting of an alpha- and beta-subunit, maintains the sodium gradient across the plasma membrane. A functional relationship between E-cadherin and Na,K-ATPase has not previously been described. We present evidence that the Na,K-ATPase plays a crucial role in E-cadherin-mediated development of epithelial polarity, and suppression of invasiveness and motility of carcinoma cells. Moloney sarcoma virus-transformed Madin-Darby canine kidney cells (MSV-MDCK) have highly reduced levels of E-cadherin and beta(1)-subunit of Na,K-ATPase. Forced expression of E-cadherin in MSV-MDCK cells did not reestablish epithelial polarity or inhibit the invasiveness and motility of these cells. In contrast, expression of E-cadherin and Na,K-ATPase beta(1)-subunit induced epithelial polarization, including the formation of tight junctions and desmosomes, abolished invasiveness, and reduced cell motility in MSV-MDCK cells. Our results suggest that E-cadherin-mediated cell-cell adhesion requires the Na,K-ATPase beta-subunit's function to induce epithelial polarization and suppress invasiveness and motility of carcinoma cells. Involvement of the beta(1)-subunit of Na,K-ATPase in the polarized phenotype of epithelial cells reveals a novel link between the structural organization and vectorial ion transport function of epithelial cells.

Cleavage and Shedding of E-cadherin after Induction of Apoptosis

Apoptotic cell death induces dramatic molecular changes in cells, becoming apparent on the structural level as membrane blebbing, condensation of the cytoplasm and nucleus, and loss of cell-cell contacts. The activation of caspases is one of the fundamental steps during programmed cell death. Here we report a detailed analysis of the fate of the Ca(2+)-dependent cell adhesion molecule E-cadherin in apoptotic epithelial cells and show that during apoptosis fragments of E-cadherin with apparent molecular masses of 24, 29, and 84 kDa are generated by two distinct proteolytic activities. In addition to a caspase-3-mediated cleavage releasing the cytoplasmic domain of E-cadherin, a metalloproteinase sheds the extracellular domain from the cell surface during apoptosis. Immunofluorescence analysis confirmed that concomitant with the disappearance of E-cadherin staining at the cell surface, the E-cadherin cytoplasmic domain accumulates in the cytosol. In the presence of inhibitors of caspase-3 and/or metalloproteinases, cleavage of E-cadherin was almost completely blocked. The simultaneous cleavage of the intracellular and extracellular domains of E-cadherin may provide a highly efficient mechanism to disrupt cadherin-mediated cell-cell contacts in apoptotic cells, a prerequisite for cell rounding and exit from the epithelium.

Modulation of metastasis phenotypes of non-small cell lung cancer cells by 17-allylamino 17-demethoxy geldanamycin

Background. Cancer cells that overexpress c-erbB oncogenes exhibit resistance to chemotherapy, enhanced tumorigenicity, as well as increased propensity for metastasis. The aim of this study was to investigate if depletion of erbB-1/EGFR and erbB-2/HER2neu oncogene products by 17-allylamino 17-demethoxy Geldanamycin (17AAGA) could diminish the metastatic potential of non-small cell lung cancer (NSCLC) cells that express varying levels of the erbB1/erbB2 oncogenes. Methods. NSCLC cell lines (H460, H358, H322, or H661) were assayed for expression of erbB1 and erbB2, the cell adhesion molecule E-cadherin, secretion of the matrix metalloproteinase 9 (MMP-9), and vascular endothelial cell growth factor (VEGF), as well as their ability to invade Matrigel after 48-hour exposure to 17AAGA. Results. 17AAGA significantly depleted erbB1 or erbB2 levels in NSCLC cells expressing high levels of these proteins, and effectively inhibited their growth with IC 50 values ranging from 50 to 90 nmol/L. Moreover, drug treatment enhanced E-cadherin expression in H322 and H358 cells, and inhibited secretion of MMP-9 and VEGF secretion by tumor cells. 17AAGA diminished hypoxia-induced upregulation of VEGF expression as well as growth factor-mediated augmentation of MMP-9 secretion, and profoundly inhibited the ability of H322 and H358 cells to migrate through Matrigel in response to chemoattractants. Conclusions. In addition to its known antiproliferative and chemosensitization effects, 17AAGA inhibits the metastatic phenotype of lung cancer cells. 17AAGA may be a novel pharmacologic agent for specific molecular intervention in lung cancer patients.

Expression of CD44v6 but not E‐cadherin or β‐catenin influences prognosis in primary pulmonary adenocarcinoma

Primary pulmonary adenocarcinoma was studied, looking for relationships between the expression of cell adhesion molecules (CAMs) E-cadherin, β-catenin and CD44v6, and clinicopathological tumour parameters and patient post-operative survival. Formalin-fixed, paraffin-embedded tissue from 120 primary lung adenocarcinomas, including 23 poorly differentiated tumours, 17 of probable bronchial origin, and 29 with a prominent bronchioloalveolar pattern, together with nodal metastatic tumour from 34 of these patients was stained using monoclonal antibodies and immunohistochemistry. Sections were scored either high level (>10% cells positive) or low level (<10% positive). High level expression of CD44v6 was retained in 28.4% (34/120) of tumours, while high levels of E-cadherin (57.5%, 69/120) and β-catenin (80.8%, 97/120) were more frequent. For all CAMs, staining levels did not correlate with nodal status, stage or tumour type. The apical or basal staining seen in normal bronchial and alveolar epithelium was often seen in papillary, glandular, and bronchioloalveolar areas of tumour, while solid invasive tumour more often showed pericellular staining. When the staining for each CAM in 34 nodal metastases was compared with that in the corresponding primary tumour, a high degree of concordance was found, with no tendency for metastases to show less staining than the primary tumour. Expression of E-cadherin and β-catenin in the primary tumour had no influence on post-operative survival, but patients whose tumours had low level CD44v6 expression had a poorer post-operative survival than those with high levels of CD44v6 (p=0.0014 for all patients, p=0.0012 for stage I patients only). In primary pulmonary adenocarcinoma, the levels of expression of E-cadherin, β-catenin, and CD44v6 are not associated with lymph node metastases or tumour stage but the staining pattern is associated with tumour morphology. Low levels of CD44v6 expression predict a poor post-operative survival, independently of stage, while there is no such relationship with the expression of E-cadherin or β-catenin. Copyright © 2000 John Wiley & Sons, Ltd.

Expression of the Homeobox Gene, Barx2, in Wool Follicle Development

We have cloned ovine Barx2, a member of the Bar class of homeobox genes, and present the first description of Barx2 expression in wool follicle development. Barx2 is uniformly expressed in the embryonic ectoderm but is transiently downregulated during the initiation of follicle morphogenesis. Subsequently, Barx2 is expressed throughout the epithelial component of the developing follicle except for a small group of cells at the leading edge of the follicle placode. These Barx2-negative cells are destined to form the follicle bulb and are the progenitors of the inner root sheath and hair shaft. In adult follicles, Barx2 is expressed throughout the outer root sheath but not in the inner root sheath or hair shaft, or in dermal cells associated with the follicle. The pattern of Barx2 expression in follicle morphogenesis is similar to that of the cell adhesion molecule E-cadherin, a similarity that echoes Barx2 coexpression with the L1 cell adhesion molecule in other tissues during mouse embryogenesis. Barx2 is also expressed in tongue and esophagus, two other keratinizing tissues, and we speculate that Barx2 may have a general function in controlling adhesive processes in keratinizing epithelia.

The use of molecular biology in diagnosis and prognosis of gastric cancer

The investigation of molecular and genetic changes in gastric cancer has brought new insights into the pathogenesis of the disease. Knowledge of the genetic abnormalities and altered molecules could be used for differential diagnosis in case of an unknown primary tumor, allows their evaluation as prognostic factors, and could open novel avenues for more specific clinical interventions. Clinically relevant molecules whose expression or structure is altered include the plasminogen activator and its inhibitor plasminogen activator inhibitor type 1, the cell cycle regulator cyclin E, epidermal growth factor, the apoptosis inhibitor bcl-2, the cell adhesion molecule E-cadherin, and the multifunctional protein beta-Catenin. In addition, genetic instability is commonly seen. Gene amplification and protein overexpression of the growth factor receptors c-erbB2 and K- sam may be prognostic factors for intestinal- and diffuse-type gastric cancer, respectively. There has long been evidence for a genetic predisposition to gastric cancer by epidemiological studies and case reports. Very recently, germ line mutations of E-cadherin have been identified that are responsible for a dominantly inherited from of diffuse-type gastric cancer and could be used to identify individuals that are at high risk. The clinical implications of the recent findings for diagnosis, prognosis, therapy, and risk assessment are discussed.

Phenotypic and genotypic characterization of commonly used human prostatic cell lines.

To investigate and catalogue systematically the phenotypic and genotypic characteristics of the commonly used prostatic cell lines using immunocytochemistry and polymerase chain reaction (PCR) of hypervariable sequences within the genome to provide a 'fingerprint' characteristic of each cell line. Materials and methods Malignant (LNCaP, LNCaP-r, PC-3, DU-145) and benign immortalized prostatic cell lines (PNT-1A, PNT-1B, BPH-1) were grown on four-well slides, fixed and subjected to indirect streptavidin-biotin immunocytochemistry. Twenty-three antibodies were used in the following groups: cytoskeletal elements: cytokeratins (CK)-5, -7, -8, -14 (two), -16, -18, -19 (three), -20, vimentin and desmin; MUC1 (three); cell adhesion molecules (E-cadherin, alpha-beta-and gamma-catenin); and prostatic associated proteins: prostate specific antigen (PSA), prostatic acid phosphatase (PAP) and androgen receptor (AR). For the PCR, genomic DNA was extracted from the cell lines and from SKOV3 and MCF7 (positive controls). PCR was performed on three variable regions which were then sequenced: AR exon 1 (CAG repeat polymorphism), and two areas of microsatellite instability (MSI): AR exon 8 and hypoxanthine-guanine phosphoribosyl transferase (HPRT) exon 3. All cell lines were CK-8/18 positive and most also expressed CK-7 and -19. Heterogeneous CK-20 expression was detected for the first time in prostatic cell lines. All lines were positive for vimentin and negative for desmin. MUC1 was expressed in one malignant (DU-145) and all immortalized cell lines. E-cadherin expression was low or absent in three lines: PNT1A, 1B and PC-3. Only PC-3 failed to express alpha-catenin; beta- and gamma-catenin were expressed by all lines. PSA, PAP and AR were only expressed by LNCaP and LNCaP-r. On PCR, the CAG repeat lengths in exon 1 of the AR ranged from 19 to 27. Three pairs of cell lines had the same exon 1 CAG repeat length: LNCaP/PC-3 (26 repeats), BPH-1/DU-145 (19 repeats) and PNT1 A/1B (20 repeats). Exon 8 sequences were identical except for LNCaP, which showed a single base mutation, and HPRT exon 3 sequences were all identical. There was no evidence of generalized MSI in any of the cell lines examined. The cell lines studied fell into three broad groups according to their phenotypic characteristics: (i) prostatic marker positive (LNCaP and LNCaP-r); (ii) high expression of most antigens (DU-145, PC-3 and BPH-1); and (iii) low or absent expression of most antigens (PNT1 A and 1B). Each of the cell lines derived from PC could be identified on the basis of exon 1 and 8 AR sequence variability. DU145 and BPH-1 had identical profiles of the three areas studied, but these cell lines are easily distinguished by their different phenotypic characteristics. PNT1A and 1B had identical genetic and similar phenotypic profiles, which is unsurprising given that they are subclones derived from the same parental line. Even so, these were separable on the basis of CK-19 immunostaining. Using a combination of geno- and phenotypic markers it was possible to derive a 'fingerprint' for each of the cell lines assessed, which will allow meaningful comparison between similar cell lines held in other laboratories.

Ancillary methods for the detection of recurrent urothelial neoplasia

Ancillary methods for the detection of recurrent urothelial neoplasia

Complex cadherin expression in human prostate cancer cells

Changes in cell-cell interactions are critical in the process of cancer progression. Likewise, it has been shown that loss of expression of the cell adhesion molecule E-cadherin is associated with grade, stage, and prognosis in many carcinomas, including prostate cancer. Impaired E-cadherin-mediated interactions result in an invasive phenotype; however, the mere loss of cell-cell contact and communication is not the sole explanation for the observed correlation between loss of E-cadherin-mediated adhesion and poor clinical outcome. Using a degenerate cloning strategy for sequences that are highly conserved between the various cadherins, we found several other cadherins (N- and P-cadherin and cadherin-4, -6, and -11) to be expressed in human prostate cancer cells. Our data suggest that besides loss of E-cadherin function, also (upregulation of) expression of other cadherins is involved in the acquisition of an invasive and/or metastatic phenotype. Especially, changes in the expression of N-cadherin and cadherin-11 may play an important role in prostate cancer progression.

Expression of CD44v6 but not E-cadherin or beta-catenin influences prognosis in primary pulmonary adenocarcinoma.

Primary pulmonary adenocarcinoma was studied, looking for relationships between the expression of cell adhesion molecules (CAMs) E-cadherin, beta-catenin and CD44v6, and clinicopathological tumour parameters and patient post-operative survival. Formalin-fixed, paraffin-embedded tissue from 120 primary lung adenocarcinomas, including 23 poorly differentiated tumours, 17 of probable bronchial origin, and 29 with a prominent bronchioloalveolar pattern, together with nodal metastatic tumour from 34 of these patients was stained using monoclonal antibodies and immunohistochemistry. Sections were scored either high level (>10% cells positive) or low level (<10% positive). High level expression of CD44v6 was retained in 28.4% (34/120) of tumours, while high levels of E-cadherin (57.5%, 69/120) and beta-catenin (80. 8%, 97/120) were more frequent. For all CAMs, staining levels did not correlate with nodal status, stage or tumour type. The apical or basal staining seen in normal bronchial and alveolar epithelium was often seen in papillary, glandular, and bronchioloalveolar areas of tumour, while solid invasive tumour more often showed pericellular staining. When the staining for each CAM in 34 nodal metastases was compared with that in the corresponding primary tumour, a high degree of concordance was found, with no tendency for metastases to show less staining than the primary tumour. Expression of E-cadherin and beta-catenin in the primary tumour had no influence on post-operative survival, but patients whose tumours had low level CD44v6 expression had a poorer post-operative survival than those with high levels of CD44v6 (p=0.0014 for all patients, p=0.0012 for stage I patients only). In primary pulmonary adenocarcinoma, the levels of expression of E-cadherin, beta-catenin, and CD44v6 are not associated with lymph node metastases or tumour stage but the staining pattern is associated with tumour morphology. Low levels of CD44v6 expression predict a poor post-operative survival, independently of stage, while there is no such relationship with the expression of E-cadherin or beta-catenin.