Expression of CEACAM1 in adenocarcinoma of the lung: a factor of independent prognostic significance

The role of carcinoembryonic antigen-related cell adhesion molecule 1 in cancer

The Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1), also known as CD66a, is a member of the immunoglobulin superfamily. CEACAM1 was shown to be a prognostic marker in patients suffering from cancer. In this review, we summarize pre-clinical and clinical evidence linking CEACAM1 to tumorigenicity and cancer progression. Furthermore, we discuss potential CEACAM1-based mechanisms that may affect cancer biology.

Inhibitory innate receptors and their potential role in transplantation

The regulatory arm of the immune system plays a crucial role in maintaining immune tolerance and preventing excessive immune responses. Immune regulation comprises various regulatory cells and molecules that work together to suppress or regulate immune responses. The programmed cell death protein 1 (PD-1) and cytotoxic T lymphocyte-associated protein 4 (CTLA-4) are examples of inhibitory receptors that counteract activating signals and fine-tune immune responses. While most of the discoveries of immune regulation have been related to T cells and the adaptive immune system, the innate arm of the immune system also has a range of inhibitory receptors that can counteract activating signals and suppress the effector immune responses. Targeting these innate inhibitory receptors may provide a complementary therapeutic approach in several immune-related conditions, including transplantation. In this review, we will explore the potential role of innate inhibitory receptors in controlling alloimmunity during solid organ transplantation.

Activation of CEACAM1 with an agonistic monoclonal antibody results in inhibition of melanoma cells

Inhibitory receptors (IRs), such as the carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1), are cell surface molecules expressed on both normal epithelial, endothelial, and hematopoietic cells and on neoplastic cells. IRs are usually used by cancer cells to inhibit immune cell functions. Thus, CEACAM1 positive tumor cells can interact homophilically with CEACAM1 expressed on T and NK cells to inhibit their antibody-dependent cell-mediated cytotoxicity (ADCC). In this study, we investigated the effect of agonistic/activating anti-CEACAM1 monoclonal antibody (mAb) on melanoma cell lines in vitro and in vivo, following our hypothesis that activation of CEACAM1 on melanoma cells by distinct mAbs may induce inhibition of cancer cell proliferation and/or their death. To address this, we established an activating anti-CEACAM1 mAb (CCM5.01) and characterized its binding to the CEACAM1 receptor. Using this mAb, we assessed the expression of CEACAM1 on four different human melanoma cell lines by western blot and flow cytometry and determined its effect on cell viability in vitro by MTT assay. Furthermore, we evaluated the mAb mechanism of action and found that binding of CEACAM1 with CCM5.01 induced SHP1 phosphorylation and p53 activation resulting in melanoma cell apoptosis. For in vivo studies, a xenograft model of melanoma was performed by injection of Mel-14 cells subcutaneously (s.c.) in SCID/Beige mice followed by intraperitoneal (i.p.) injection of CCM5.01 or of IgG1 isotype control every other day. CCM5.01 treated mice showed a slight but not significant decrease in tumor weight in comparison to the control group. Based on the obtained data, we suggest that activating CEACAM1 on melanoma cells might be a promising novel approach to fight cancers expressing this IR.

A bioinformatics-based study on the Cisplatin-resistant lung cancer cells; what are the orchestrators of this phenom?

Lung cancer represents a significant global health issue and is among the central causes of mortality and morbidity around the world. Unfortunately, the majority of lung cancer patients acquire drug resistant to chemotherapy either intrinsically or acquired after Cisplatin treatment. It is indicated that increasing or decreasing the expression of particular genes can affect chemotherapeutic sensitivity or resistance. As a result, gaining a deeper knowledge of the changed expression of genes implicated in lung cancer drug resistance, as well as developing novel therapeutic techniques, are critical targets for continued advancement in lung cancer treatment. In the present study, we aimed to find key regulatory genes in the progression of Cisplatin resistance in A-549 lung cancer cells. In this regard, microarray dataset of Cisplatin-resistant and Cisplatin-sensitive was retrieved from the Gene Expression Omnibus (GEO) with accession number of GSE108214. Then, differentially expressed genes (DEGs) between sensitive and resistant lung cancer cells were obtained by using R software v4.0.2 and related packages. We recognized CEACAM1, DGKA, ARHGEF4, and THSD4 are involved in the drug resistance. Experimentally, Cisplatin-resistant A-549 cells were developed and analyzed by MTT assay. Besides, the expression of candidate genes were analyzed in these cells compared to Cisplatin-sensitive A-549 cells by qRT-PCR. The findings presented that the expression of CEACAM1, DGKA, ARHGEF4, and THSD4 was altered following the induction of Cisplatin resistance in A549 cells.

Genome-wide analysis of mRNA and microRNA expression in colorectal cancer and adjacent normal mucosa

mRNA expression varies in human cancers. Such altered mRNA expression is negatively regulated by the expression of microRNAs (miRNAs), which play an important role in human tumorigenesis. According to this theory, inverse mRNA/miRNA expression may be a direct driver of cancer development, and certain genetic events may occur prior to the development of any discernible histological abnormalities. We examined the inverse expression between mRNAs and their corresponding miRNAs in colorectal cancer (CRC) and adjacent normal mucosa and performed pathway analysis to identify mRNA/miRNA networks. The cancer samples were divided into first (20 cases) and second (24 cases) cohorts, and 48 samples were obtained from two sections of the normal mucosa adjacent to the tumors from the second cohort. We investigated mRNAs with commonly altered expression in CRC and adjacent normal mucosa using isolated cancer glands and normal crypts from the first cohort, compared with that of distal normal crypts, using an array-based method. As a result, significant inverse correlations between CEACAM1 and miRNA-7114-5p and between AK1 and miRNA-6780-5p were found in CRC and adjacent normal mucosa. We validated these correlations in the second cohort using RT-PCR. To confirm these findings, transfection and immunohistochemical assays were also performed, which verified the inverse correlation between CEACAM1 and miRNA-7114-5p. Our findings suggest that the inverse correlations between the CEACAM1/miRNA-7114-5p and possibly AK1/miRNA-6780-5p pairs play an important role in early CRC development, and may help identify potential molecular targets for early detection of CRC.

Unraveling the Expression Patterns of Immune Checkpoints Identifies New Subtypes and Emerging Therapeutic Indicators in Lung Adenocarcinoma

Immune checkpoint genes (ICGs) play pivotal roles in tumor immune microenvironment (TIME), and thus, targeting them represents a promising strategy for cancer immunotherapy. However, the genetic landscape of ICGs in lung adenocarcinoma (LUAD) is still unknown. Herein, we comprehensively evaluated the ICG expression profiles of 1439 LUAD samples and linked ICG expression patterns with infiltration of immune cells, clinical features, and response to immune checkpoint blockade (ICB). The ICGscore was developed to quantify ICG expression patterns of individual patient by principal component analysis algorithms. Three distinct ICG expression patterns and three ICG-related genomic clusters were determined, which were implicated in different clinical outcomes, level of immune infiltrates, and biological process. LUAD patients were subdivided into high- and low-ICGscore subgroups. Patients with higher ICGscore were characterized by favorable survival outcomes, increased immune cell infiltration, and enhanced expression of ICGs. Further analysis revealed that lower ICGscore was associated with greater tumor mutation loads and higher mutation rates of TTN, KEAP1, and ZFHX4. High ICGscore has the potential to be a robust indicator in clinical benefit of immunotherapy. Taken together, unraveling the ICG expression patterns will advance our understanding of heterogeneity of TIME and guides more effective immunotherapeutic strategies in LUAD.

Perinatal Exposure to Nicotine Alters Sperm RNA Profiles in Rats

Perinatal exposure to smoking has been associated with childhood asthma, one of the most common pediatric conditions affecting millions of children globally. Of great interest, this disease phenotype appears heritable as it can persist across multiple generations even in the absence of persistent exposure to smoking in subsequent generations. Although the molecular mechanisms underlying childhood asthma induced by perinatal exposure to smoking or nicotine remain elusive, an epigenetic mechanism has been proposed, which is supported by the data from our earlier analyses on germline DNA methylation (5mC) and histone marks (H3 and H4 acetylation). To further investigate the potential epigenetic inheritance of childhood asthma induced by perinatal nicotine exposure, we profiled both large and small RNAs in the sperm of F1 male rats. Our data revealed that perinatal exposure to nicotine leads to alterations in the profiles of sperm-borne RNAs, including mRNAs and small RNAs, and that rosiglitazone, a PPARγ agonist, can attenuate the effect of nicotine and reverse the sperm-borne RNA profiles of F1 male rats to close to placebo control levels.

Peripheral blood transcriptome heterogeneity and prognostic potential in lung cancer revealed by RNA-Seq

Understanding of the complex interaction between the peripheral immune system and lung cancer (LC) remains incomplete, limiting patient benefit. Here, we aimed to characterize the host peripheral immune response to LC and investigate its potential prognostic value. Bulk RNA-sequencing data of peripheral blood leucocytes (PBLs) from healthy volunteers and LC patients (n = 142) were analysed for characterization of host systemic immunity in LC. We observed broad blood transcriptome perturbations in LC patients that were heterogeneous, as two new subtypes were established independent of histology. Functionally, the heterogeneity between the two subtypes included dysregulation of diverse biological processes, such as the cell cycle, blood coagulation and inflammatory signalling pathways, together with the abundance and activity of blood cells, particularly lymphocytes and neutrophils, ultimately manifesting as differences in antitumour immune status. Based on these findings, a prognostic model composed of ten genes dysregulated in one LC subtype with relatively poor immune status was developed and validated in a Gene Expression Omnibus (GEO) data set (n = 108), helping to generate a prognostic nomogram. Collectively, our study provides novel and comprehensive insight into the heterogeneity of the host peripheral immune response to LC. The expression heterogeneity-based predictive model may help guide prognostic management for LC patients.

Integrative Analysis of Genome, 3D Genome, and Transcriptome Alterations of Clinical Lung Cancer Samples

Genomic studies of cancer cell alterations, such as mutations, copy number variations (CNVs), and translocations, greatly promote our understanding of the genesis and development of cancer. However, the 3D genome architecture of cancers remains less studied due to the complexity of cancer genomes and technical difficulties. To explore the 3D genome structure in clinical lung cancer, we performed Hi-C experiments using paired normal and tumor cells harvested from patients with lung cancer, combining with RNA-seq analysis. We demonstrated the feasibility of studying 3D genome of clinical lung cancer samples with a small number of cells (1 × 10⁴), compared the genome architecture between clinical samples and cell lines of lung cancer, and identified conserved and changed spatial chromatin structures between normal and cancer samples. We also showed that Hi-C data can be used to infer CNVs and point mutations in cancer. By integrating those different types of cancer alterations, we showed significant associations between CNVs, 3D genome, and gene expression. We propose that 3D genome mediates the effects of cancer genomic alterations on gene expression through altering regulatory chromatin structures. Our study highlights the importance of analyzing 3D genomes of clinical cancer samples in addition to cancer cell lines and provides an integrative genomic analysis pipeline for future larger-scale studies in lung cancer and other cancers.

Loss of CEACAM1 is associated with poor prognosis and peritoneal dissemination of patients with gastric cancer

CEACAM1 is associated with malignant potential of various cancers. The current study aims to clarify the association between carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) expression and malignant potential of gastric cancer and to address whether CEACAM1 cytoplasmic domain isoform balance modulates the properties of gastric cancer cells. Immunohistochemical analyses for CEACAM1 were performed in 235 patients with gastric cancer who underwent surgery. Risk factors for overall survival and peritoneal metastasis were calculated based on CEACAM1 expression in the gastric cancer tissue. Patients with CEACAM1 long (CEACAM1-L) or short (CEACAM1-S) cytoplasmic isoform dominance were compared with patients with null CEACAM1 expression in terms of overall survival. CEACAM1 transfected or knockdown gastric cancer cell line, NUGC3 and MKN7 cells, were examined by invasion assay and three dimensional (3D) culture, in order to clarify whether CEACAM1 modulate invasion, lumen formation and tumor growth of gastric cancer cells. Multivariate analysis demonstrated that gastric cancer without CEACAM1 is an independent prognostic factor and a risk factor for peritoneal dissemination. Patients with CEACAM1-S dominance had better prognosis than those with CEACAM1-L. CEACAM1-4L overexpression induced less invasion, more lumen formation, and less tumor growth of NUGC3 cells. CEACAM1-4S overexpression had less invasion and more lumen formations, but not less tumor growth. Knockdown of CEACAM1 expression had less invasion, but not less lumen formations of MKN7 cells. Loss of CEACAM1 is associated with poor prognosis and peritoneal dissemination of patients with gastric cancer. Expression of CEACAM1 in gastric cancer cells modulates invasiveness, lumen formation, and tumor growth.

Expression of Chosen Carcinoembryonic-Related Cell Adhesion Molecules in Pancreatic Intraepithelial Neoplasia (PanIN) Associated with Chronic Pancreatitis and Pancreatic Ductal Adenocarcinoma (PDAC)

Aims: Carcinoembryonic antigen-related cell adhesion molecules (CEACAMs) are members of the glycosylphosphatidylinositol (GPI)-linked immunoglobulin (Ig) superfamily and take part in regulation of cell adhesion, tumor suppression and angiogenesis. Overexpression of CEACAM 1, 5 and 6 is widely described in several gastrointestinal epithelial tumors. The aim of study was to evaluate the expression of CEACAM 1, CEACAM 5 and CEACAM 6 in the most common precursor lesions of pancreatic ductal adenocarcinoma -pancreatic intraepithelial neoplasia (PanIN). Methods and results: The study group consisted of 32 patients treated for chronic pancreatitis and 38 patients with pancreatic ductal adenocarcinoma who also had pancreatic intraepithelial neoplasia. The expression of CEACAM was performed by immunohistochemical method and evaluated using 3-point scale: 0 - lack of positive reaction in pancreatic intraepithelial neoplasia, 1 (weak and moderate) - reaction present in 1-30% epithelial cells in PanIN and 2 (strong) - reaction present in >30% epithelial cells in PanIN. Expression of CEACAM 1, 5 and 6 increased with increasing degree of advancement of PanIN. Differences in expression of CEACAM 1, 5 and 6 between normal pancreatic ducts and different degrees of PanIN were statistically significant (p<0.001). We observed relationship between CEACAM1 expression and localization of PanIN in different parts of the pancreas. Conclusions: CEACAM 1, CEACAM 5 and CEACAM 6 expression appears to be an early event in pancreatic carcinogenesis. Moreover, expression of CEACAM 1, 5 and 6 may represent a useful biomarker that may aid in the identification of precancerous lesions in the pancreas.

On the Dual Role of Carcinoembryonic Antigen-Related Cell Adhesion Molecule 1 (CEACAM1) in Human Malignancies

Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) is a glycoprotein belonging to the carcinoembryonic antigen (CEA) family that is expressed on a wide variety of cells and holds a complex role in inflammation through its alternate splicing and generation of various isoforms, mediating intricate mechanisms of modulation and dysregulation. Initially regarded as a tumor suppressor as its expression shows considerable downregulation within the epithelia in the early phases of many solid cancers, CEACAM1 has been linked lately to the progression of malignancy and metastatic spread as various papers point to its role in tumor progression, angiogenesis, and invasion. We reviewed the literature and discussed the various expression patterns of CEACAM1 in different types of tumors, describing its structure and general biologic functions and emphasizing the most significant findings that link this molecule to poor prognosis. The importance of understanding the role of CEACAM1 in cell transformation stands not only in this adhesion molecule's value as a prognostic factor but also in its promising premise as a potential new molecular target that could be exploited as a specific cancer therapy.

Prognostic Impact of CEACAM1 in Node-Negative Ovarian Cancer Patients

The underlying mechanisms of ovarian cancer (OvCa) dissemination are still poorly understood, and novel molecular markers for this cancer type are urgently needed. In search of adhesion molecules with prognostic relevance in OvCa, we compared tumors with good outcome (alive > 3 years) and those with poor outcome (dead < 2 years) within data from The Cancer Genome Atlas (TCGA). The carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) turned out as the only gene with differential expression in these groups. In order to further investigation on its role in OvCa, we analyzed CEACAM1 mRNA levels extracted from TCGA microarray data (n = 517) as well as CEACAM1 protein expression by Western blot analysis in a cohort of 242 tumor samples. Further, CEACAM1 localization in tumour tissue was evaluated by immunohistochemistry and CEACAM1 splice variants by RT-PCR in representative tumours. In Kaplan–Meier analysis, high CEACAM1 mRNA levels significantly correlated with longer survival (p = 0.008). By Western blot analysis in the second cohort, similar associations of high CEACAM1 protein levels with longer recurrence-free survival (RFS, p = 0.035) and overall survival (OAS, p = 0.004) were observed. In multivariate Cox regression analysis including clinical prognostic parameters, CEACAM1 mRNA or protein expression turned out as independent prognostic markers. Stratified survival analysis showed that high CEACAM1 protein expression was prognostic in node-negative tumors (p = 0.045 and p = 0.0002 for DFS and OAS) but lost prognostic significance in node-positive carcinomas. Similarly, high CEACAM1 mRNA expression did not show prognostic relevance in tumors with lymphatic invasion (L1) but was associated with longer survival in cases without lymphovascular involvement. Further analysis showed a predominance of 4S and 4L isoforms and mostly membraneous CEACAM1 localization in ovarian tumours. Our results suggest that CEACAM1 might be an independent favorable prognostic marker in OvCa, especially in the subgroup of patients with solely intraperitoneal metastasis.

Knockdown of CEACAM19 suppresses human gastric cancer through inhibition of PI3K/Akt and NF-κB

Gastric cancer directly affects the quality of human life worldwide. Some members, which belong to carcinoembryonic antigen-related cell adhesion molecule (CEACAM) subfamily, are deregulated in tumors. Of the subfamily, CEACAM19, a new member was the research object. Our study sought to explore the potential role of CEACAM19 in gastric cancer. According to the immunohistochemistry (IHC), RT-PCR and Western blot, CEACAM19 was over-expressed in gastric cancer tissues and cells. Moreover, the Western blot analysis showed that the expression of MMP2 and MMP9 was inhibited in CEACAM19 knockdown gastric cancer cells. Meanwhile, in SGC-7901 and MGC-803 cells, the knockdown of CEACAM19 reduced proliferation, migration and invasion. Additionally, the Western blot assay revealed that the phosphorylation levels of Akt and p65 were declined by the knockdown of CEACAM19. Furthermore, the influence of CEACAM19 knockdown was confirmed by the studies in vivo. Collectively, our results revealed that the CEACAM19 knockdown prevented the gastric cancer progression likely related to inactivating the PI3K/Akt and NF-κB signaling pathways. Our findings provided insights into a promising biomarker of gastric cancer and the potential molecule clues for the prevention of gastric cancer.

A liquid biopsy for bronchopulmonary/lung carcinoid diagnosis

No effective blood biomarker exists to detect and clinically manage bronchopulmonary (BP) neuroendocrine tumors (NET). We developed a blood-based 51 NET-specific transcript set for diagnosis and monitoring and evaluated clinical performance metrics. It accurately diagnosed the tumor and differentiated stable from progressive disease as determined by RECIST criteria. Gene expression was evaluated in: a) publicly available BPNET transcriptomes (GSE35679); b) two BPNET cell-lines; and c) BPNET tissue with paired blood (n = 7). Blood gene expression was assessed in 194 samples including controls, benign lung diseases, malignant lung diseases and small bowel NETs. A separate validation study in 25 age- and gender-matched BPNETs/controls was performed. Gene expression measured by real-time PCR was scored (0–100%; normal: < 14%). Regression analyses, Principal Component Analysis (PCA), hierarchical clustering, Fisher's and non-parametric evaluations were undertaken. All 51 genes were identified in BPNET transcriptomes, tumor samples and cell-lines. Significant correlations were evident between paired tumor and blood (R2:0.63–0.91, p < 0.001). PCA and hierarchical clustering identified blood gene expression was significantly different between lung cancers and benign diseases, including BPNETs. Gene expression was highly correlated (R²: 0.91, p = 1.7 × 10-¹⁵) between small bowel and BPNET. For validation, all 25 BPNETs were positive compared to 20% controls (p < 0.0001). Scores were significantly elevated (p < 0.0001) in BPNETs (57 ± 28%) compared to controls (4 ± 5%). BPNETs with progressive disease (85 ± 11%) exhibited higher scores than stable disease (32 ± 7%, p < 0.0001). Blood measurements accurately diagnosed bronchopulmonary carcinoids, distinguishing stable from progressive disease. This marker panel will have clinical utility as a diagnostic liquid biopsy able to define disease activity and progression in real-time.

CEACAM1 is associated with recurrence after hepatectomy for colorectal liver metastasis

BACKGROUND

Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) is re-expressed at the invasion front of colorectal cancer. CEACAM1 expression at metastatic sites remains to be investigated. The current study aims to clarify the association between CEACAM1 expression and recurrence after hepatectomy of colorectal liver metastasis and to address whether CEACAM1 induces tumor-initiating properties needed for growth at metastatic sites.

METHODS

Immunohistochemical analyses for CEACAM1 were performed in 67 patients with liver metastasis of colorectal cancer who had undergone curative hepatectomy. The risk factors for postoperative recurrence were calculated based on a CEACAM1 cytoplasmic domain isoform at the primary tumor invasion front. To investigate the effects of CEACAM1 cytoplasmic isoforms on HT29 and HCT116 colorectal cancer cells, Western blotting for CD44 and CD133, flow cytometry for ALDH1 activity, and soft-agar colony formation assay were performed.

RESULTS

CEACAM1 long (CEACAM1-L) and short (CEACAM1-S) cytoplasmic domain isoforms are strongly expressed on cancer cells in the liver metastases. Enhanced CEACAM1-S expression in the state of CEACAM1-L dominance at the primary tumor invasion front was an independent factor for colorectal cancer recurrence after curative hepatectomy. CEACAM1-4S-transfected HT29 and HCT116 cells had significantly higher CD44 expression and ALDH1 activity and increased the growth in anchorage-independent condition.

CONCLUSIONS

High expression of CEACAM1-S at the primary lesion invasion front is associated with recurrence and prognosis of patients with colorectal liver metastasis after curative hepatectomy. The expression of CEACAM1-4S enhances the tumor-initiating property of colorectal cancer cells.

The GalNAc-T Activation Pathway (GALA) is not a general mechanism for regulating mucin-type O-glycosylation

Mucin-type O-glycosylation is initiated by the UDP-GalNAc polypeptide:N-acetylgalactosaminyltransferase (GalNAc-T) family of enzymes. Their activity results in the GalNAc α1-O-Thr/Ser structure, termed the Tn antigen, which is further decorated with additional sugars. In neoplastic cells, the Tn antigen is often overexpressed. Because O-glycosylation is controlled by the activity of GalNAc-Ts, their regulation is of great interest. Previous reports suggest that growth factors, EGF or PDGF, induce Golgi complex-to-endoplasmic reticulum (ER) relocation of both GalNAc-Ts and Tn antigen in HeLa cells, offering a mechanism for Tn antigen overexpression termed "GALA". However, we were unable to reproduce these findings. Upon treatment of HeLa cells with either EGF or PDGF we observed no change in the co-localization of endogenous GalNAc-T1, GalNAc-T2 or Tn antigen with the Golgi complex marker TGN46. There was also no enhancement of localization with the ER marker calnexin. We conclude that growth factors do not cause redistribution of GalNAc-Ts from the Golgi complex to the ER in HeLa cells.

CEACAM1 as a multi-purpose target for cancer immunotherapy

CEACAM1 is an extensively studied cell surface molecule with established functions in multiple cancer types, as well as in various compartments of the immune system. Due to its multi-faceted role as a recently appreciated immune checkpoint inhibitor and tumor marker, CEACAM1 is an attractive target for cancer immunotherapy. Herein, we highlight CEACAM1's function in various immune compartments and cancer types, including in the context of metastatic disease. This review outlines CEACAM1's role as a therapeutic target for cancer treatment in light of these properties.

CEACAM1 long isoform has opposite effects on the growth of human mastocytosis and medullary thyroid carcinoma cells

Carcinoembryonic antigen‐related cell adhesion molecule 1 (CEACAM1) is expressed in a number of tumor cell types. The immunoreceptor tyrosine‐based inhibitory motif (ITIM)‐containing isoforms of this molecule which possess a long cytoplasmic tail (CEACAM1‐L) generally play inhibitory roles in cell function by interacting with Src homology 2 domain‐containing tyrosine phosphatase (SHP)‐1 and/or SHP‐2. Src family kinases (SFKs) are also known to bind to and phosphorylate CEACAM1‐L isoforms. Here, we report that CEACAM1 was uniquely expressed at high levels in both human neoplastic mast cells (mastocytosis) and medullary thyroid carcinoma cell (MTC) lines, when compared with their expression in nonneoplastic mast cells or nonneoplastic C cells. This expression was mainly derived from CEACAM1‐L isoforms based upon assessment of CEACAM1 mRNA expression. CEACAM1 knockdown upregulated cell growth of HMC1.2 cells harboring KIT mutations detected in clinical mastocytosis, whereas downregulated the growth of TT cells harboring RET mutations detected in clinical MTCs. Immunoblotting, ELISA and immunoprecipitaion analysis showed that activated SHP‐1 is preferentially associated with CEACAM1 in HMC1.2 cells harboring KIT mutations, whereas Src family kinases (SFKs) are preferentially associated with CEACAM1 in TT cells harboring RET mutations. These studies suggest that the dominantly interacting proteins SHP1 or SFK determine whether CEACAM1‐L displays a positive or negative role in tumor cells.

High expression of CEACAM19, a new member of carcinoembryonic antigen gene family, in patients with breast cancer

Carcinoembryonic antigen (CEA) family members play important roles in malignancies and are introduced as biomarkers in different types of cancers. Among them CEACAM19 (CEAL1) gene, a new member of the CEA family, remains to be fully elucidated. The aim of this study was investigating the mRNA expression level of CEACAM19 in tumor samples of breast cancer patients compared to breast tissue of normal individuals. We evaluated the expression level of this gene in 75 breast tumors by using real-time quantitative PCR. Also, we studied the correlation between CEACAM19 expression and clinicopathological features and hormone receptors status, including estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 of patients. Out of the enrolled patients, six of them (7.9%) showed low expression, ten (13.2%) showed normal expression and 59 (77.6%) showed high expression of CEACAM19. There was a significant correlation between high expression of CEACAM19 gene in tumor samples compared to normal tissues (P = 0.039). No significant correlation was seen between clinicopathological factors and disease-free survival with mRNA levels of CEACAM19 in tumor samples, while the difference between the expression of CEACAM19 in ER/PR-positive and ER/PR-negative breast cancer patients was statistically significant (P = 0.046). In conclusion, CEACAM19 showed high expression in tumor samples compared to normal mammary tissue. In addition, CEACAM19 may represent as a novel therapeutic target in certain subgroups of breast cancer patients such as ER/PR-negative. Critical roles of CEA proteins in tumor progression may nominate them as robust potential targets for therapeutic intervention in near future.

The role of CEA-related cell adhesion molecule-1 (CEACAM1) in vascular homeostasis

Carcinoembryonic antigen (CEA)-related cell adhesion molecules belong to the immunoglobulin superfamily, are expressed in a broad spectrum of tissues and cell types and exert context-dependent activating as well as inhibitory effects. Among these molecules, the CEA-related cell adhesion molecule-1 (CEACAM1) is a transmembrane molecule with an extracellular, a transmembrane and a cytoplasmic domain. The latter contains immunoreceptor tyrosine-based inhibitory motifs and functions as a signaling molecule. CEACAM1 can form homo- and heterodimers which is relevant for its signaling activities. CEACAM1 acts as co-receptor that modulates the activity of different receptor types including VEGFR-2, and B and T cell receptors. CEACAM1 is expressed in endothelial cells, in pericytes of developing and newly formed immature blood vessels and in angiogenically activated adult vessels, e.g., tumor blood vessels. However, it is either undetectable or only weakly expressed in quiescent blood vessels. Recent studies indicated that CEACAM1 is involved in the regulation of the endothelial barrier function. In CEACAM1 ^-/- mice, increased vascular permeability and development of small atherosclerotic lesions was observed in the aortae. CEACAM1 is also detectable in activated lymphatic endothelial cells and plays a role in tumor lymphangiogenesis. This review summarizes the vascular effects of CEACAM1 and focuses on its role in vascular morphogenesis and endothelial barrier regulation.

CEACAM1 controls the EMT switch in murine mammary carcinoma in vitro and in vivo

We analyzed the molecular basis for carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1)-controlled inhibition of epithelial-mesenchymal transition (EMT) in a mouse model for mammary adenocarcinoma (WAP-T mice). We demonstrate that silencing of CEACAM1 in WAP-T tumor-derived G-2 cells induces epithelial-mesenchymal plasticity (EMP), as evidenced by typical changes of gene expression, morphology and increased invasion. In contrast, reintroduction of CEACAM1 into G-2 cells reversed up-regulation of genes imposing mesenchymal transition, as well as cellular invasion. We identified the Wnt-pathway as target for CEACAM1-mediated repression of EMT. Importantly, β-catenin phosphorylation status and transcriptional activity strongly depend on CEACAM1 expression: CEACAM1high G-2 cells displayed enhanced phosphorylation of β-catenin at S33/S37/T41 and decreased phosphorylation at Y86, thereby inhibiting canonical Wnt/β-catenin signaling. We identified Src-homology 2 domain-containing phosphatase 2 (SHP-2) as a critical binding partner of CEACAM1 that could modulate β-catenin Y86 phosphorylation. Hence, CEACAM1 serves as a scaffold that controls membrane proximal β-catenin signaling. In vivo, mammary tumors of WAP-T/CEACAM1null mice displayed increased nuclear translocation of β-catenin and a dramatically enhanced metastasis rate compared to WAP-T mice. Hence, CEACAM1 controls EMT in vitro and in vivo by site-specific regulation of β-catenin phosphorylation. Survival analyses of human mammary carcinoma patients corroborated these data, indicating that CEACAM1 is a prognostic marker for breast cancer survival.

CEACAM1 is overexpressed in oral tumors and related to tumorigenesis

Carcinoembryonic antigen-related adhesion molecule 1 (CEACAM1) is a type 1 transmembrane glycoprotein belonging to the CEA family, which has been known to exist as either soluble forms in body fluids or membrane-bound forms on the cell surface. Aberrant CEACAM1 expression is associated with tumorigenesis and has been reported in a variety of human tumors, especially malignancies. The aim of this study is to determine the expression of CEACAM1 in oral tumors, trying to study CEACAM1 different expressions as a function of histotype. CEACAM1 expression was observed by immunohistochemistry (IHC) with mouse anti-human antibody for CEACAM1. IHC was performed using avidin-biotin-diaminobenzidine staining. The results were expressed as average score ± SD (0 = negative/8 = highest) for each histotype. Oral tumors expressed more CEACAM1 than normal tissues including squamous and salivary epithelia (P < 0.05). In malignancies, the squamous cell carcinoma overexpressed CEACAM1, compared to well-differentiated squamous cell with more membranous expression; the intermediately and poorly differentiated squamous cell carcinoma showed more cytoplasmic expression (P < 0.05). In addition, the salivary tumors significantly expressed more CEACAM1 than squamous cell carcinoma (P < 0.05). So, we thought oral tumors overexpressed CEACAM1 and the cytoplasmic CEACAM1 might be involved in tumorigenesis, and also CEACAM1 might be regarded as a marker of salivary glandular tumors.

The human antibody fragment DIATHIS1 specific for CEACAM1 enhances natural killer cell cytotoxicity against melanoma cell lines in vitro

Supplemental Digital Content is available in the text.

Several lines of evidence show that de novo expression of carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) is strongly associated with reduced disease-free survival of patients affected by metastatic melanoma. Previously published investigations report that homophilic interactions between CEACAM1 expressed on natural killer (NK) cells and tumors inhibit the NK cell-mediated killing independently of major histocompatibility complex class I recognition. This biological property can be physiologically relevant in metastatic melanoma because of the increased CEACAM1 expression observed on NK cells from some patients. Moreover, this inhibitory mechanism in many cases might hinder the efficacy of immunotherapeutic treatments of CEACAM1⁺ malignancies because of tumor evasion by activated effector cells. In the present study, we designed an in vitro experimental model showing that the human single-chain variable fragment (scFv) DIATHIS1 specific for CEACAM1 is able to enhance the lytic machinery of NK cells against CEACAM1⁺ melanoma cells. The coincubation of the scFv DIATHIS1 with CEACAM1⁺ melanoma cells and NK-92 cell line significantly increases the cell-mediated cytotoxicity. Moreover, pretreatment of melanoma cells with scFv DIATHIS1 promotes the activation and the degranulation capacity of in vitro–expanded NK cells from healthy donors. It is interesting to note that the melanoma cell line MelC and the primary melanoma cells STA that respond better to DIATHIS1 treatment, express higher relative levels of CEACAM1-3L and CEACAM1-3S splice variants isoforms compared with Mel501 cells that are less responsive to DIATHIS1-induced NK cell–mediated cytotoxicity. Taken together, our results suggest that the fully human antibody fragment DIATHIS1 originated by biopanning approach from a phage antibody library may represent a relevant biotechnological platform to design and develop completely human antimelanoma therapeutics of biological origin.

Absence of CD66a expression is associated with high microvessel density and high histologic grade in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a primary malignancy of the liver. Patients with HCC usually have poor prognosis and high mortality. It has been shown that carcinoembryonic antigen-related cell adhesion molecule 1 (CD66a) regulates cell signaling, proliferation, and tumor growth. The aim of this study is to analyze the expression and possible role of CD66a in HCC. Immunohistochemical staining of CD66a was performed on 86 HCC cases, and microvessel density was evaluated by CD34 immunostaining. The results were further correlated with clinicopathological parameters. For 47 of 86 HCC cases, the CD66a expression showed diffuse membrane or cytoplasmic staining. The other 39 HCC cases revealed loss of CD66a expression. Loss of CD66a expression was statistically significantly associated with large tumor size (p=0.016), fatty change (p=0.039), patients with transcatheter arterial embolization (p=0.007), and high microvessel density (p=0.036). CD34 expression had no significant association with tumor size, virus infection, histological grade, and capsular invasion. The diffuse and cytoplasmic expression of CD66a may involve the early stage of the HCC, and the loss of CD66a expression indicates tumor progression.

Carcinoembryonic antigen-related cell adhesion molecule 1 is expressed and as a function histotype in ovarian tumors

Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) is a cell-cell adhesion receptor and is implicated in several cellular functions. It is rarely reported in ovarian tumors. The aim of this study is to determine the expression of CEACAM1 in ovarian tumors, trying to see whether CEACAM1 has different expression patterns as a function of histotype. Antigen expression was examined by immunohistochemistry with mouse anti-human antibody for CEACAM1. Immunohistochemistry was performed using avidin-biotin-diaminobenzide staining. The results were expressed as average score ± SD (0, negative; 8, highest) for each histotype. In ovarian tumors, the benign serous and mucinous cystadenoma negatively or weakly expressed CEACAM1, the malignant epithelial tumors strongly expressed CEACAM1, and there was significant difference between benign epithelial tumor and adenocarcinoma (P < .05). The well-differentiated serous adenocarcinoma expressed CEACAM1 mainly with membrane pattern, and the intermediately and poorly differentiated serous adenocarcinomas expressed CEACAM1 mainly with cytoplasmic pattern (P < .05). In addition, CEACAM1 expression is elevated in solid tumors of ovary but variable as a function of histotype. Compared with membranous expression, the cytoplasmic expression was observed almost in metastatic carcinoma that might decrease the adhesive interactions of the carcinoma cells with the surrounding cells, especially with tumor cells, and this could facilitate the tumor cells to metastasize to distant regions. So, we thought that cytoplasmic CEACAM1 might play an important role in tumor progression, especially in tumor metastasis.

A549 cells adapted to high nitric oxide show reduced surface CEACAM expression and altered adhesion and migration properties

The migration and adhesion properties of tumors affect their metastatic rate. In the present study, we investigated carcinoembryonic antigen-related cell adhesion molecule (CEACAM) 1, 5, and 6 expression in high nitric oxide (HNO)-adapted lung cancer cells compared to parent cells. We observed high transcript levels of CEACAM 1 (4S, 4L), CEACAM 5, and CEACAM 6 in HNO cells compared to parent cells. However, the surface expression was low in HNO cells. Interestingly, the intracellular protein levels were high for these three CEACAMs. We confirmed these results with immunohistochemical experiments. Further, the adhesion and migration assays showed reduced clumping in HNO-adapted A549 (A549-HNO) cells and faster migration rates, respectively. These results document the altered adhesion and migration properties of cells adapted to HNO. Further, our studies also indicate a dynamic regulation of CEACAM protein expression and surface transport in HNO cells.

CEACAM5 has different expression patterns in gastric non-neoplastic and neoplastic lesions and cytoplasmic staining is a marker for evaluation of tumor progression in gastric adenocarcinoma

OBJECTIVE

The aim of this study was to investigate the expression patterns of CEACAM5 in non-neoplastic and neoplastic gastric lesions, as well as its application in the differential diagnosis and its relationship with tumor progression.

METHODS

CEACAM5 expression was detected by immunohistochemical staining in the serial sections of the gastric neoplastic and non-neoplastic lesions. The impacts of CEACAM5 expression patterns on tumor progression were evaluated by statistics, the clinical and pathological data included sex, age, tumor extension, lymph node involvement and tumor staging.

RESULTS

There was no CEACAM5 expression in normal gastric epithelial cells. In hyperplastic polyps, CEACAM5 was expressed with apical membranous staining in the hyperplastic and prolonged gastric pit adjacent to the surface. Intestinal metaplasia (IM) expressed CEACAM5 mainly with membranous pattern, and some cases showed membranous staining mixed with cytoplasmic staining. GIN expressed CEACAM5 mainly with membranous staining, but the mixed staining of cytoplasmic and membranous patterns increased, and especially in the high grade GIN, cytoplasmic staining of CEACAM5 began to occur. Compared with IM and GIN, CEACAM5 expression patterns of hyperplastic polyp showed a significant difference (P=0.000). IM, low grade GIN and the whole GIN showed no significant difference in CEACAM5 expression patterns (P=0.355), but IM and high grade GIN showed a significant difference (P=0.027). There was a significant difference between low and high grade GIN (P=0.002). GIN and well-differentiated carcinomas showed no significant difference (P=0.070), but low grade GIN and well differentiated carcinomas showed a significant difference (P=0.006). In gastric adenocarcinomas, CEACAM5 expression patterns showed a significant difference in tumor grading (P=0.010) and Laurén classification (P=0.001). In histological grading, well differentiated carcinomas showed more membranous staining than moderately and poorly differentiated, and more cytoplasmic CEACAM5 staining was detected in moderately and poorly differentiated carcinomas. Similar to that, in Laurén classification, intestinal carcinomas showed more membranous staining, and diffuse carcinomas showed more cytoplasmic staining. Moreover, CEACAM5 expression patterns showed a significant difference in tumor extension (P=0.012), lymph node involvement (P=0.015) and tumor staging (P=0.002), suggesting that CEACAM5 should be involved in tumor progression. In advanced carcinomas, CEACAM5 was expressed with more cytoplasmic staining regardless of the histological classification.

CONCLUSION

CEACAM5 had different expression patterns in gastric non-neoplastic and neoplastic lesions. The CEACAM5 expression patterns were associated with tumor progression. Membranous staining of CEACAM5 might be a marker of premalignancy in gastric lesions, and cytoplasmic CEACAM5 might enhance tumor invasion and migration and be an evaluated marker for progressive and advanced gastric cancer. Also, it might be useful for the differential diagnosis of gastric premalignant lesions.

Serum CA19-9 is significantly upregulated up to 2 years before diagnosis with pancreatic cancer: implications for early disease detection

PURPOSE

Biomarkers for the early detection of pancreatic cancer are urgently needed. The primary objective of this study was to evaluate whether increased levels of serum CA19-9, CA125, CEACAM1, and REG3A are present before clinical presentation of pancreatic cancer and to assess the performance of combined markers for early detection and prognosis.

EXPERIMENTAL DESIGN

This nested case-control study within the UKCTOCS included 118 single and 143 serial serum samples from 154 postmenopausal women who were subsequently diagnosed with pancreatic cancer and 304 matched noncancer controls. Samples were split randomly into independent training and test sets. CA19-9, CA125, CEACAM1, and REG3A were measured using ELISA and/or CLIA. Performance of markers to detect cancers at different times before diagnosis and for prognosis was evaluated.

RESULTS

At 95% specificity, CA19-9 (>37 U/mL) had a sensitivity of 68% up to 1 year, and 53% up to 2 years before diagnosis. Combining CA19-9 and CA125 improved sensitivity as CA125 was elevated (>30 U/mL) in approximately 20% of CA19-9-negative cases. CEACAM1 and REG3A were late markers adding little in combined models. Average lead times of 20 to 23 months were estimated for test-positive cases. Prediagnostic levels of CA19-9 and CA125 were associated with poor overall survival (HR, 2.69 and 3.15, respectively).

CONCLUSIONS

CA19-9 and CA125 have encouraging sensitivity for detecting preclinical pancreatic cancer, and both markers can be used as prognostic tools. This work challenges the prevailing view that CA19-9 is upregulated late in the course of pancreatic cancer development.

CEACAM1 promotes melanoma cell growth through Sox-2

The prognostic value of the carcinoembryonic antigen cell adhesion molecule 1 (CEACAM1) in melanoma was demonstrated more than a decade ago as superior to Breslow score. We have previously shown that intercellular homophilic CEACAM1 interactions protect melanoma cells from lymphocyte-mediated elimination. Here, we study the direct effects of CEACAM1 on melanoma cell biology. By employing tissue microarrays and low-passage primary cultures of metastatic melanoma, we show that CEACAM1 expression gradually increases from nevi to metastatic specimens, with a strong dominance of the CEACAM1-Long tail splice variant. Using experimental systems of CEACAM1 knockdown and overexpression of selective variants or truncation mutants, we prove that only the full-length long tail variant enhances melanoma cell proliferation in vitro and in vivo. This effect is not reversed with a CEACAM1-blocking antibody, suggesting that it is not mediated by intercellular homophilic interactions. Downstream, CEACAM1-Long increases the expression of Sox-2, which we show to be responsible for the CEACAM1-mediated enhanced proliferation. Furthermore, analysis of the CEACAM1 promoter reveals two single-nucleotide polymorphisms (SNPs) that significantly enhance the promoter's activity compared with the consensus nucleotides. Importantly, case-control genetic SNP analysis of 134 patients with melanoma and matched healthy donors show that patients with melanoma do not exhibit the Hardy-Weinberg balance and that homozygous SNP genotype enhances the hazard ratio to develop melanoma by 35%. These observations shed new mechanistic light on the role of CEACAM1 in melanoma, forming the basis for development of novel therapeutic and diagnostic technologies.

Gene expression profiling reveals GC and CEACAM1 as new tools in the diagnosis of lung carcinoids

Background:

Classification of lung carcinoids into typical and atypical is a diagnostic challenge since no immunohistochemical tools are available to support pathologists in distinguishing between the two subtypes. A differential diagnosis is essential for clinicians to correctly discuss therapy, prognosis and follow-up with patients. Indeed, the distinction between the two typical and atypical subtypes on biopsies/cytological specimens is still unfeasible and sometimes limited also after radical surgeries. By comparing the gene expression profile of typical (TC) and atypical carcinoids (AC), we intended to find genes specifically expressed in one of the two subtypes that could be used as diagnostic markers.

Methods:

Expression profiling, with Affymetrix arrays, was performed on six typical and seven atypical samples. Data were validated on an independent cohort of 29 tumours, by means of quantitative PCR and immunohistochemistry (IHC).

Results:

High-throughput gene expression profiling was successfully used to identify a gene signature specific for atypical lung carcinoids. Among the 273 upregulated genes in the atypical vs typical subtype, GC (vitamin D-binding protein) and CEACAM1 (carcinoembryonic antigen family member) emerged as potent diagnostic markers. Quantitative PCR and IHC on a validation set of 17 ACs and 12 TCs confirmed their reproducibility and feasibility.

Conclusions:

GC and CEACAM1 can distinguish between TC and AC, defining an IHC assay potentially useful for routine cytological and histochemical diagnostic procedures. The high sensitivity and reproducibility of this new diagnostic algorithm strongly support a further validation on a wider sample size.

Carcinoembryonic antigen (CEA)-related cell adhesion molecules are co-expressed in the human lung and their expression can be modulated in bronchial epithelial cells by non-typable Haemophilus influenzae, Moraxella catarrhalis, TLR3, and type I and II interferons

Background

The carcinoembryonic antigen (CEA)-related cell adhesion molecules CEACAM1 (BGP, CD66a), CEACAM5 (CEA, CD66e) and CEACAM6 (NCA, CD66c) are expressed in human lung. They play a role in innate and adaptive immunity and are targets for various bacterial and viral adhesins. Two pathogens that colonize the normally sterile lower respiratory tract in patients with chronic obstructive pulmonary disease (COPD) are non-typable Haemophilus influenzae (NTHI) and Moraxella catarrhalis. Both pathogens bind to CEACAMs and elicit a variety of cellular reactions, including bacterial internalization, cell adhesion and apoptosis.

Methods

To analyze the (co-) expression of CEACAM1, CEACAM5 and CEACAM6 in different lung tissues with respect to COPD, smoking status and granulocyte infiltration, immunohistochemically stained paraffin sections of 19 donors were studied. To address short-term effects of cigarette smoke and acute inflammation, transcriptional regulation of CEACAM5, CEACAM6 and different CEACAM1 isoforms by cigarette smoke extract, interferons, Toll-like receptor agonists, and bacteria was tested in normal human bronchial epithelial (NHBE) cells by quantitative PCR. Corresponding CEACAM protein levels were determined by flow cytometry.

Results

Immunohistochemical analysis of lung sections showed the most frequent and intense staining for CEACAM1, CEACAM5 and CEACAM6 in bronchial and alveolar epithelium, but revealed no significant differences in connection with COPD, smoking status and granulocyte infiltration. In NHBE cells, mRNA expression of CEACAM1 isoforms CEACAM1-4L, CEACAM1-4S, CEACAM1-3L and CEACAM1-3S were up-regulated by interferons alpha, beta and gamma, as well as the TLR3 agonist polyinosinic:polycytidylic acid (poly I:C). Interferon-gamma also increased CEACAM5 expression. These results were confirmed on protein level by FACS analysis. Importantly, also NTHI and M. catarrhalis increased CEACAM1 mRNA levels. This effect was independent of the ability to bind to CEACAM1. The expression of CEACAM6 was not affected by any treatment or bacterial infection.

Conclusions

While we did not find a direct correlation between CEACAM1 expression and COPD, the COPD-associated bacteria NTHi and M. catarrhalis were able to increase the expression of their own receptor on host cells. Further, the data suggest a role for CEACAM1 and CEACAM5 in the phenomenon of increased host susceptibility to bacterial infection upon viral challenge in the human respiratory tract.

Clinical and experimental studies regarding the expression and diagnostic value of carcinoembryonic antigen-related cell adhesion molecule 1 in non-small-cell lung cancer

Background

Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) is a multifunctional Ig-like cell adhesion molecule that has a wide range of biological functions. According to previous reports, serum CEACAM1 is dysregulated in different malignant tumours and associated with tumour progression. However, the serum CEACAM1 expression in non-small-cell lung carcinomas (NSCLC) is unclear. The different expression ratio of CEACAM1-S and CEACAM1-L isoform has seldom been investigated in NSCLC. This research is intended to study the serum CEACAM1 and the ratio of CEACAM1-S/L isoforms in NSCLC.

Methods

The expression of the serum CEACAM1 was determined by enzyme-linked immunosorbent assay. The protein expression and the location of CEACAM1 in tumours were observed by immunohistochemical staining. The CEACAM1 mRNA levels in tumour and normal adjacent tissues were measured using quantitative real-time PCR, and the expression patterns and the rate of CEACAM1-S and CEACAM1-L were analysed by reverse transcription-PCR.

Results

Serum CEACAM1 levels were significantly higher in NSCLC patients compared with that from normal healthy controls (P <0.0001). 17 patients (81%) among 21 showed high expression of CEACAM1 by immunohistochemical staining. Although no significant differences were found between tumour and normal tissues on mRNA expression levels of CEACAM1 (P >0.05), the CEACAM1-S and the CEACAM1-S/L (S: L) ratios were significantly higher in tumour than normal tissues (P <0.05).

Conclusions

Our data indicated that the serum levels of CEACAM1 could discriminate lung cancer patients from health donors and that CEACAM1 might be a useful marker in early diagnosis of NSCLC. Moreover, our results showed that the expression patterns of CEACAM1 isoforms could be changed during oncogenesis, even when total CEACAM1 in tumour tissues did not show significant changes. Our study suggested that the expression ratios of CEACAM1-S/CEACAM1-L might be a better diagnostic indicator in NSCLC than the quantitative changes of CEACAM1.

CEA-Related CAMs

The carcinoembryonic antigen (CEA) family comprises a large number of cellular surface molecules, the CEA-related cell adhesion molecules (CEACAMs), which belong to the Ig superfamily. CEACAMs exhibit a complex expression pattern in normal and malignant tissues. The majority of the CEACAMs are cellular adhesion molecules that are involved in a great variety of distinct cellular processes, for example in the integration of cellular responses through homo- and heterophilic adhesion and interaction with a broad selection of signal regulatory proteins, i.e., integrins or cytoskeletal components and tyrosine kinases. Moreover, expression of CEACAMs affects tumor growth, angiogenesis, cellular differentiation, immune responses, and they serve as receptors for commensal and pathogenic microbes. Recently, new insights into CEACAM structure and function became available, providing further elucidation of their kaleidoscopic functions.

Novel immunotherapy for malignant melanoma with a monoclonal antibody that blocks CEACAM1 homophilic interactions

CEACAM1 (biliary glycoprotein-1, CD66a) was reported as a strong clinical predictor of poor prognosis in melanoma. We have previously identified CEACAM1 as a tumor escape mechanism from cytotoxic lymphocytes. Here, we present substantial evidence in vitro and in vivo that blocking of CEACAM1 function with a novel monoclonal antibody (MRG1) is a promising strategy for cancer immunotherapy. MRG1, a murine IgG1 monoclonal antibody, was raised against human CEACAM1. It recognizes the CEACAM1-specific N-domain with high affinity (K(D) ~ 2 nmol/L). Furthermore, MRG1 is a potent inhibitor of CEACAM1 homophilic binding and does not induce any agonistic effect. We show using cytotoxicity assays that MRG1 renders multiple melanoma cell lines more vulnerable to T cells in a dose-dependent manner, only following antigen-restricted recognition. Accordingly, MRG1 significantly enhances the antitumor effect of adoptively transferred, melanoma-reactive human lymphocytes using human melanoma xenograft models in severe combined immunodeficient/nonobese diabetic (SCID/NOD) mice. A significant antibody-dependent cell cytotoxicity response was excluded. It is shown that MRG1 reaches the tumor and is cleared within a week. Importantly, approximately 90% of melanoma specimens are CEACAM1(+), implying that the majority of patients with melanoma could be amenable to MRG1-based therapy. Normal human tissue microarray displays limited binding to luminal epithelial cells on some secretory ducts, which was weaker than the broad normal cell binding of other anticancer antibodies in clinical use. Importantly, MRG1 does not directly affect CEACAM1(+) cells. CEACAM1 blockade is different from other immunomodulatory approaches, as MRG1 targets inhibitory interactions between tumor cells and late effector lymphocytes, which is thus a more specific and compartmentalized immune stimulation with potentially superior safety profile.

Serum CEACAM1 Correlates with Disease Progression and Survival in Malignant Melanoma Patients

The search for melanoma biomarkers is crucial, as the incidence of melanoma continues to rise. We have previously demonstrated that serum CEACAM1 (sCEACAM1) is secreted from melanoma cells and correlates with disease progression in metastatic melanoma patients. Here, we have used a different cohort of melanoma patients with regional or metastatic disease (N = 49), treated with autologous vaccination. By monitoring sCEACAM1 in serum samples obtained prior to and after vaccination, we show that sCEACAM1 correlates with disease state, overall survival, and S100B. The trend of change in sCEACAM1 following vaccination (increase/decrease) inversely correlates with overall survival. DTH skin test is used to evaluate patients' anti-melanoma immune response and to predict response to vaccination. Importantly, sCEACAM1 had a stronger prognostic value than that of DTH, and when sCEACAM1 decreased following treatment, this was the dominant predictor of increased survival. Collectively, our results point out the relevance of sCEACAM1 in monitoring melanoma patients.

The evaluation of SOX9 expression and its relationship with carcinoembryonic antigen-related cell adhesion molecule 1 in gastric neoplastic and nonneoplastic lesions

The aims of this study were to investigate the expression of SOX9 (sex determining region Y [SRY]-related high-mobility group box 9) and carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) in benign, premalignant, and malignant gastric lesions and to explore the association between SOX9 and CEACAM1 in gastric carcinogenesis. SOX9 and CEACAM1 expression was detected in normal gastric mucosa, hyperplastic polyp, intestinal metaplasia, gastric intraepithelial neoplasia, and adenocarcinoma by immunohistochemistry. There was low expression of SOX9 and no CEACAM1 expression in normal gastric mucosa and hyperplastic polyps. Intestinal metaplasia began to express CEACAM1 and showed more membranous staining of CEACAM1 than normal mucosa and hyperplastic polyps (P = .000), but SOX9 expression had no significant difference, and the coexpression of SOX9 and CEACAM1 ascended; therefore, the difference was significant (P = .000). Gastric intraepithelial neoplasia showed more SOX9 expression, coexpression of SOX9, and CEACAM1 than in intestinal metaplasia (P = .014 and P = .026, respectively). Carcinoma showed more cytoplasmic CEACAM1 (P = .010), more SOX9 expression (P = .001), and more their coexpression (P = .023) than gastric intraepithelial neoplasia. As to the histologic classification, poorly differentiated carcinoma showed more cytoplasmic CEACAM1 than well and moderately differentiated carcinoma (P = .006 and P = .024, respectively). In the Laurén classification, diffuse carcinoma showed more cytoplasmic CEACAM1 than intestinal carcinoma (P = .0035), but the SOX9 expression and their coexpresison showed no difference (P = .065 and P = .074, respectively). With the elevation of SOX9 expression and the changing of CEACAM1 expression patterns, the coexpressions of SOX9 and CEACAM1 were highly elevated from benign proliferative lesions to malignant lesions. Moreover, the SOX9 expression and the coexpression with CEACAM1 were correlated positively (r = 0.310; P = .015). In addition, SOX9 expression was positively correlated with CEACAM1 expression patterns (r = 0.124; P = .032). In addition, CEACAM1 expression patterns and coexpression of SOX9 and CEACAM1 show significant difference between T1 and T2 and T3 and T4 (P = .021 and P = .011, respectively). Accordingly, compared with N0, N2 and N3 showed significant difference in SOX9 expression (P = .018), CEACAM1 expression patterns (P = .010), and their coexpression (P = .010). SOX9 expression significantly increased from nonneoplastic lesions to neoplastic lesions, and CEACAM1 expression patterns markedly changed; their coexpression also showed signally elevated suggesting that SOX9, as a transcriptional regulator, play important roles in the changing of CEACAM1 expression patterns, which might promote the tumor progression.

Investigations on the usefulness of CEACAMs as potential imaging targets for molecular imaging purposes

Members of the carcinoembryonic antigen cell adhesion molecules (CEACAMs) family are the prototype of tumour markers. Classically they are used as serum markers, however, CEACAMs could serve as targets for molecular imaging as well.

In order to test the anti CEACAM monoclonal antibody T84.1 for imaging purposes, CEACAM expression was analysed using this antibody. Twelve human cancer cell lines from different entities were screened for their CEACAM expression using qPCR, Western Blot and FACS analysis. In addition, CEACAM expression was analyzed in primary tumour xenografts of these cells. Nine of 12 tumour cell lines expressed CEACAM mRNA and protein when grown in vitro. Pancreatic and colon cancer cell lines showed the highest expression levels with good correlation of mRNA and protein level. However, when grown in vivo, the CEACAM expression was generally downregulated except for the melanoma cell lines. As the CEACAM expression showed pronounced expression in FemX-1 primary tumours, this model system was used for further experiments. As the accessibility of the antibody after i.v. application is critical for its use in molecular imaging, the binding of the T84.1 monoclonal antibody was assessed after i.v. injection into SCID mice harbouring a FemX-1 primary tumour. When applied i.v., the CEACAM specific T84.1 antibody bound to tumour cells in the vicinity of blood vessels. This binding pattern was particularly pronounced in the periphery of the tumour xenograft, however, some antibody binding was also observed in the central areas of the tumour around blood vessels. Still, a general penetration of the tumour by i.v. application of the anti CEACAM antibody could not be achieved despite homogenous CEACAM expression of all melanoma cells when analysed in tissue sections. This lack of penetration is probably due to the increased interstitial fluid pressure in tumours caused by the absence of functional lymphatic vessels.

Hollow spheroids beyond the invasive margin indicate the malignant potential of colorectal cancer

Objective Tumour budding formed by histologically undifferentiated cancer cells beyond the border of the tumour margin is associated with lymph node metastasis. However, hollow tumour nests, a possible histologically advanced phenotype of tumour budding, have not been discussed. We examined whether hollow spheroids exist beyond the border of the invasive margin and are associated with metastasis and prognosis. Moreover, we suggest that carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) isoform balance is associated with hollow spheroid formation. Methods Immunohistochemical analyses with CEACAM1 and M30 as an apoptosis marker were performed to examine the importance of hollow spheroid CEACAM1 expression and central cell apoptosis in hollow spheroid formation. The correlations between the presence of hollow spheroids beyond the invasive margin and the clinicopathological characteristics of 314 patients with colorectal cancer were retrospectively evaluated. A 3D culture with colorectal cancer cells transfected with CEACAM1 cDNA or shRNA was used to determine whether CEACAM1 isoform balance controls colorectal hollow spheroid formation. Results Hollow spheroid formation accompanying central cell apoptosis was confirmed by M30 staining and serial section with CEACAM1 staining. Of the 314 patients, 96 (30.4%) were classified as having hollow spheroids. The presence of hollow spheroids is an independent risk factor for metastases and shorter survival. In 3D culture, CEACAM1 isoform balance modulated hollow spheroid formation of colorectal cancer cells. Conclusions Hollow spheroid formation beyond the border of the tumour margin in colorectal cancer is more important than tumour budding for the prediction of malignant potential.

Ceacam1 separates graft-versus-host-disease from graft-versus-tumor activity after experimental allogeneic bone marrow transplantation

Background

Allogeneic bone marrow transplantation (allo-BMT) is a potentially curative therapy for a variety of hematologic diseases, but benefits, including graft-versus-tumor (GVT) activity are limited by graft-versus-host-disease (GVHD). Carcinoembryonic antigen related cell adhesion molecule 1 (Ceacam1) is a transmembrane glycoprotein found on epithelium, T cells, and many tumors. It regulates a variety of physiologic and pathological processes such as tumor biology, leukocyte activation, and energy homeostasis. Previous studies suggest that Ceacam1 negatively regulates inflammation in inflammatory bowel disease models.

Methods

We studied Ceacam1 as a regulator of GVHD and GVT after allogeneic bone marrow transplantation (allo-BMT) in mouse models. In vivo, Ceacam1^−/− T cells caused increased GVHD mortality and GVHD of the colon, and greater numbers of donor T cells were positive for activation markers (CD25^hi, CD62L^lo). Additionally, Ceacam1^−/− CD8 T cells had greater expression of the gut-trafficking integrin α₄β₇, though both CD4 and CD8 T cells were found increased numbers in the gut post-transplant. Ceacam1^−/− recipients also experienced increased GVHD mortality and GVHD of the colon, and alloreactive T cells displayed increased activation. Additionally, Ceacam1^−/− mice had increased mortality and decreased numbers of regenerating small intestinal crypts upon radiation exposure. Conversely, Ceacam1-overexpressing T cells caused attenuated target-organ and systemic GVHD, which correlated with decreased donor T cell numbers in target tissues, and mortality. Finally, graft-versus-tumor survival in a Ceacam1⁺ lymphoma model was improved in animals receiving Ceacam1^−/− vs. control T cells.

Conclusions

We conclude that Ceacam1 regulates T cell activation, GVHD target organ damage, and numbers of donor T cells in lymphoid organs and GVHD target tissues. In recipients of allo-BMT, Ceacam1 may also regulate tissue radiosensitivity. Because of its expression on both the donor graft and host tissues, this suggests that targeting Ceacam1 may represent a potent strategy for the regulation of GVHD and GVT after allogeneic transplantation.

The possible roles of OPN-regulated CEACAM1 expression in promoting the survival of activated T cells and the apoptosis of oral keratinocytes in oral lichen planus patients

Oral lichen planus is a chronic inflammatory disorder of the oral mucosa that represents T cell-mediated autoimmune diseases. The regulation and roles of carcinoembryonic antigen-related cellular adhesion molecule 1 (CEACAM1), a novel immune molecule, in the immunopathogenesis of T cell-mediated autoimmune diseases remain unclear. In the current paper, CEACAM1 was found to be overexpressed in peripheral T cells and epithelial cells in oral lichen planus patients. A fraction of infiltrating inflammatory mononuclear cells in the lamina propria of the oral lichen planus mucosa also expressed CEACAM1. Importantly, for the first time, CEACAM1 expression in T cells and in normal human oral keratinocytes was demonstrated to be regulated differently by osteopontin in vitro. Furthermore, the apoptosis of oral keratinocytes and activated T cells can be markedly suppressed by CEACAM1-specific monoclonal antibodies. In conclusion, OPN-regulated CEACAM1 expression may play a critical role in the immunopathogenesis of oral lichen planus.

Different expression patterns of CEACAM1 and its impacts on angiogenesis in gastric nonneoplastic and neoplastic lesions

OBJECTIVE

This study was designed to investigate the expression patterns of CEACAM1 and its relationship with angiogenesis in nonneoplastic and neoplastic gastric lesions.

METHODS

CEACAM1 and TGF-β expression was detected by immunohistochemical staining and dual-labeling immunohistochemical staining in neoplastic and nonneoplastic lesions. MVD-CD31 and MVD-CD105 were counted in CEACAM1-positive areas by dual-labeling immunohistochemistry.

RESULTS

There was no expression of CEACAM1 in normal gastric mucosa. In IM and GIN, CEACAM1 was mainly expressed with membranous pattern. CEACAM1 was expressed with membranous pattern in well-differentiated adenocarcinoma, with cytoplasmic pattern in poorly differentiated adenocarcinoma, and with cytoplasmic and membranous pattern mixed together in intermediately adenocarcinoma. The expression patterns of CEACAM1 showed a significant difference (P < 0.05) in nonneoplastic and neoplastic lesions. Coexpression of CEACAM1 and TGF-β was elevated and significantly different from nonneoplastic to neoplastic lesions (P < 0.05). Moreover, CEACAM1 and TGF-β coexpression were related to carcinoma progression (r = 0.35; P < 0.05). MVD-CD31 and MVD-CD105 showed significant differences from nonneoplastic to neoplastic lesions (P < 0.05).

CONCLUSIONS

CEACAM1 has different expression patterns in nonneoplastic and neoplastic lesions. The coexpression of CEACAM1 and TGF-β increased from nonneoplastic to neoplastic lesions and may be related with tumor progression via promoting tumorous angiogenesis.