CD66b, CD66c and carcinoembryonic antigen (CEA) are independently regulated markers in sera of tumor patients

A CEACAM6-High Airway Neutrophil Phenotype and CEACAM6-High Epithelial Cells Are Features of Severe Asthma

Severe asthma represents a major unmet clinical need; understanding the pathophysiology is essential for the development of new therapies. Using microarray analysis, we previously found three immunological clusters in asthma: Th2-high, Th17-high, and Th2/17-low. Although new therapies are emerging for Th2-high disease, identifying molecular pathways in Th2-low disease remains an important goal. Further interrogation of our previously described microarray dataset revealed upregulation of gene expression for carcinoembryonic Ag cell adhesion molecule (CEACAM) family members in the bronchi of patients with severe asthma. Our aim was therefore to explore the distribution and cellular localization of CEACAM6 using immunohistochemistry on bronchial biopsy tissue obtained from patients with mild-to-severe asthma and healthy control subjects. Human bronchial epithelial cells were used to investigate cytokine and corticosteroid in vitro regulation of CEACAM6 gene expression. CEACAM6 protein expression in bronchial biopsies was increased in airway epithelial cells and lamina propria inflammatory cells in severe asthma compared with healthy control subjects. CEACAM6 in the lamina propria was localized to neutrophils predominantly. Neutrophil density in the bronchial mucosa was similar across health and the spectrum of asthma severity, but the percentage of neutrophils expressing CEACAM6 was significantly increased in severe asthma, suggesting the presence of an altered neutrophil phenotype. CEACAM6 gene expression in cultured epithelial cells was upregulated by wounding and neutrophil elastase. In summary, CEACAM6 expression is increased in severe asthma and primarily associated with airway epithelial cells and tissue neutrophils. CEACAM6 may contribute to the pathology of treatment-resistant asthma via neutrophil and airway epithelial cell-dependent pathways.

Deregulation of the CEACAM expression pattern causes undifferentiated cell growth in human lung adenocarcinoma cells

CEACAM1, CEA/CEACAM5, and CEACAM6 are cell adhesion molecules (CAMs) of the carcinoembryonic antigen (CEA) family that have been shown to be deregulated in lung cancer and in up to 50% of all human cancers. However, little is known about the functional impact of these molecules on undifferentiated cell growth and tumor progression. Here we demonstrate that cell surface expression of CEACAM1 on confluent A549 human lung adenocarcinoma cells plays a critical role in differentiated, contact-inhibited cell growth. Interestingly, CEACAM1-L, but not CEACAM1-S, negatively regulates proliferation via its ITIM domain, while in proliferating cells no CEACAM expression is detectable. Furthermore, we show for the first time that CEACAM6 acts as an inducer of cellular proliferation in A549 cells, likely by interfering with the contact-inhibiting signal triggered by CEACAM1-4L, leading to undifferentiated anchorage-independent cell growth. We also found that A549 cells expressed significant amounts of non-membrane anchored variants of CEACAM5 and CEACAM6, representing a putative source for the increased CEACAM5/6 serum levels frequently found in lung cancer patients. Taken together, our data suggest that post-confluent contact inhibition is established and maintained by CEACAM1-4L, but disturbances of CEACAM1 signalling by CEACAM1-4S and other CEACAMs lead to undifferentiated cell growth and malignant transformation.

CEACAM6 acts as a receptor for adherent-invasive E. coli, supporting ileal mucosa colonization in Crohn disease

The ileal mucosa of Crohn disease (CD) patients is abnormally colonized by adherent-invasive E. coli (AIEC) that are able to adhere to and invade intestinal epithelial cells. Here, we show that CD-associated AIEC strains adhere to the brush border of primary ileal enterocytes isolated from CD patients but not controls without inflammatory bowel disease. AIEC adhesion is dependent on type 1 pili expression on the bacterial surface and on carcinoembryonic antigen-related cell adhesion molecule 6 (CEACAM6) expression on the apical surface of ileal epithelial cells. We report also that CEACAM6 acts as a receptor for AIEC adhesion and is abnormally expressed by ileal epithelial cells in CD patients. In addition, our in vitro studies show that there is increased CEACAM6 expression in cultured intestinal epithelial cells after IFN-gamma or TNF-alpha stimulation and after infection with AIEC bacteria, indicating that AIEC can promote its own colonization in CD patients.

Inhibition of adhesion, invasion, and metastasis by antibodies targeting CEACAM6 (NCA-90) and CEACAM5 (Carcinoembryonic Antigen)

CEACAM5 and CEACAM6 are overexpressed in many cancers and are associated with adhesion and invasion. The effects of three monoclonal antibodies targeting different epitopes on these antigens (NH2-terminal [MN-3] and A1B1 domains [MN-15] shared by CEACAM5 and CEACAM6 and the A3B3 domain [MN-14] restricted to CEACAM5) were evaluated in migration, invasion, and adhesion assays in vitro using a panel of human pancreatic, breast, and colonic cancer cell lines, and in the GW-39 human colonic micrometastasis model in vivo. MN-3 Fab' and MN-15 Fab' were both effective at inhibiting cell migration. MN-15 Fab' treatment inhibited invasion, reducing cell penetration through an extracellular matrix (ECM). MN-3 Fab' also decreased invasion but was less effective than MN-15 Fab' in four of five cell lines. All three monoclonal antibody (mAb) Fabs decreased adhesion of tumor cells to endothelial cells by 49% to 58%. MN-15 Fab' but not MN-3 or MN-14 Fabs induced a decrease in adhesion of three of six cell lines to the ECM protein, fibronectin, but adhesion to vitronectin, laminin, collagen-I, and collagen-IV was not affected. In vivo studies showed that treatment with MN-3 Fab' or MN-15 Fab' of mice implanted with GW-39 human colonic cancer cells increased their survival (P < 0.025 and P < 0.01, respectively). These studies show that antibody Fabs that target either CEACAM5 or CEACAM6 affect cell migration, cell invasion, and cell adhesion in vitro, and that MN-15 and MN-3 Fabs have antimetastatic effects in vivo, resulting in improved survival of mice with metastases. Thus, blocking the N and A1B1 domains of CEACAM5/CEACAM6 can impede the metastatic process.

Pathogenesis of Afa/Dr diffusely adhering Escherichia coli

Over the last few years, dramatic increases in our knowledge about diffusely adhering Escherichia coli (DAEC) pathogenesis have taken place. The typical class of DAEC includes E. coli strains harboring AfaE-I, AfaE-II, AfaE-III, AfaE-V, Dr, Dr-II, F1845, and NFA-I adhesins (Afa/Dr DAEC); these strains (i) have an identical genetic organization and (ii) allow binding to human decay-accelerating factor (DAF) (Afa/Dr(DAF) subclass) or carcinoembryonic antigen (CEA) (Afa/Dr(CEA) subclass). The atypical class of DAEC includes two subclasses of strains; the atypical subclass 1 includes E. coli strains that express AfaE-VII, AfaE-VIII, AAF-I, AAF-II, and AAF-III adhesins, which (i) have an identical genetic organization and (ii) do not bind to human DAF, and the atypical subclass 2 includes E. coli strains that harbor Afa/Dr adhesins or others adhesins promoting diffuse adhesion, together with pathogenicity islands such as the LEE pathogenicity island (DA-EPEC). In this review, the focus is on Afa/Dr DAEC strains that have been found to be associated with urinary tract infections and with enteric infection. The review aims to provide a broad overview and update of the virulence aspects of these intriguing pathogens. Epidemiological studies, diagnostic techniques, characteristic molecular features of Afa/Dr operons, and the respective role of Afa/Dr adhesins and invasins in pathogenesis are described. Following the recognition of membrane-bound receptors, including type IV collagen, DAF, CEACAM1, CEA, and CEACAM6, by Afa/Dr adhesins, activation of signal transduction pathways leads to structural and functional injuries at brush border and junctional domains and to proinflammatory responses in polarized intestinal cells. In addition, uropathogenic Afa/Dr DAEC strains, following recognition of beta(1) integrin as a receptor, enter epithelial cells by a zipper-like, raft- and microtubule-dependent mechanism. Finally, the presence of other, unknown virulence factors and the way that an Afa/Dr DAEC strain emerges from the human intestinal microbiota as a "silent pathogen" are discussed.

ProteinChip technology reveals distinctive protein expression profiles in the urine of bladder cancer patients

OBJECTIVE

Since accurate biomarkers for the early diagnosis or individual prognosis of the bladder carcinoma are still not available, we used the ProteinChip technology, to search for discriminating protein expressions associated with this cancer and its subtypes.

METHODS

A training set consisting of 30 archival urine samples from bladder carcinoma patients and 30 urinary samples from healthy volunteers, was analyzed via ProteinChip technology and computer based data mining. Mass clusters of differentially expressed proteins were verified by a second set (test set) comprising 21 bladder carcinoma urine samples and 21 non-tumor urinary samples. Expression differences between carcinoma subtype sample groups of the initial training set were assessed by a trend test.

RESULTS

Bladder carcinoma was segregated from control with a sensitivity and specificity of 80% and 90 to 97% in the trainings set, as well as 52 to 57% and 57 to 62% in the test set, respectively. Segregation of pooled tumor stages pT2-pT3 from stages pT1 and pTa was possible at the 53.3 kDa cluster of the CM10-chip array data derived rule base.

CONCLUSION

ProteinChip technology together with adapted computer based data mining tools are useful for the rapid establishment of potential protein biomarkers.

An enzyme-linked immunosorbent assay for human carcinoembryonic antigen-related cell adhesion molecule 8, a biological marker of granulocyte activities in vivo

Carcinoembryonic antigen-related cell adhesion molecule 8 (CEACAM8), also known as CD66b, NCA-95 and CD67, is a highly glycosylated protein expressed only in neutrophils and eosinophils in humans. The precise function of CEACAM8 remains unclear. As a member of the family of carcinoembryonic antigen (CEA), it may play a role in the interaction between granulocytes or between granulocytes and epithelial cells. We describe here an accurate, specific and reproducible enzyme-linked immunosorbent assay (ELISA) using purified native CEACAM8 as standard for the measurement of CEACAM8 with a detection range of 1-64 microg/l. We also present data on the levels of CEACAM8 in the blood of healthy individuals and patients undergoing surgery, as well as in patients with acute infections. The highly elevated levels of CEACAM8 in the blood of these patients, which are significantly correlated with the surface expression of CEACAM8 on neutrophils and the number of circulating neutrophils, suggest that CEACAM8 could serve as a biological marker for granulocyte activities in vivo.

Specific sample preparation in colorectal cancer

Large tissue samples from ten patients operated for colorectal cancer were prepared in the operating room in iced phosphate buffered saline, containing ethylene diaminetetraacetic acid and protease inhibitors. After cutting the specimens into small fragments, the tissues were gently pressed through a steel mesh. Membranes were permeabilized in chilled ethanol 70% to allow cytosolic fluoresceine isothiocyanate labeling, performed with anti-cytokeratin (CAM 5.2) antibodies. Samples were quantitatively sorted with a fluorescence activated cell sorter (FACS) and denatured before processing separation by two-dimensional electrophoresis on polyacrylamide gels. This procedure made it possible to sample about 4 x 10(7) viable normal and tumoral cells before fixation, and up to 4 x 10(6) cells after FACS. The gels run before and after fixation showed no major differences. The rate of cytokeratin-positive cells in the samples was the following (mean, CI 5-95%): mucosa 29.5% (8.9-66.7%), tumor 44.3% (6.6-94.8%). The epithelial cell content in colorectal cancer and normal mucosa shows important intersample variations. This is important for any comparison of fresh samples, whether at DNA, RNA, or at the protein level. We propose a method allowing the preparation of pure epithelial cell samples from normal and tumoral colonic fresh mucosa.