Biliary glycoprotein, a potential human cell adhesion molecule, is down-regulated in colorectal carcinomas

Carcinoembryonic antigen-related cell adhesion molecule 1 in cancer: Blessing or curse?

The Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1, also CD66a), a transmembrane glycoprotein of the immunoglobulin superfamily, is a pivotal mediator of various physiological and pathological processes, including oncologic disorders. However, its precise role in tumorigenicity is contradictory discussed by several clinical studies. This review aims to elucidate the clinical significance of CEACAM1 in different cancer entities focusing on tumour formation, progression and metastasis as well as on CEACAM1-mediated treatment resistance. Furthermore, we discuss the contribution of CEACAM1 to cancer immunity and modulation of the inflammatory microenvironment and finally provide a comprehensive review of treatment regimens targeting this molecule.

Characteristics of Carcinoembryonic Antigen-Related Cell Adhesion Molecules and Their Relationship to Cancer

Carcinoembryonic antigen-related cell adhesion molecules (CEACAM), such as carcinoembryonic antigen (CEA) and the oncofetal glycoprotein family, are tumor markers. The CEACAMs consist of 12 different human CEACAMs and 5 different murine CEACAMs. The CEACAM family of proteins participates in multiple biological processes that include the immune response, angiogenesis, and cancer. CEACAMs play a significant role in cancer initiation and development. Increasing evidence suggests that family members may be new cancer biomarkers and targets in that CEACEAMs tend to be aberrantly expressed and therefore may have potential diagnostic and therapeutic importance. This review systematically summarizes the biogenesis, biological properties, and functions of CEACAMs, with a focus on their relationship with cancer and potential clinical application. As our knowledge of the relationships among CEACAMs and cancer increases, and as our understanding of the involved molecular mechanisms improves, new therapeutic strategies will evolve for cancer prevention and treatment of patients with cancer.

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.

CEACAM expression in an in-vitro prostatitis model

Background

Prostatitis is an inflammatory disease of the prostate gland, which affects 2-16% of men worldwide and thought to be a cause for prostate cancer (PCa) development. Carcinoembryogenic antigen-related cell adhesion molecules (CEACAMs) are deregulated in inflammation and in PCa. The role of CEACAMs in prostate inflammation and their possible contribution to the malignant transformation of prostate epithelial cells is still elusive. In this study, we investigated the expression of CEACAMs in an in-vitro prostatitis model and their potential role in malignant transformation of prostate epithelial cells.

Methods

Normal prostate epithelial RWPE-1 cells were treated with pro-inflammatory cytokines to achieve an inflammatory state of the cells. The expression of CEACAMs and their related isoforms were analyzed. Additionally, the expression levels of selected CEACAMs were correlated with the expression of malignancy markers and the migratory properties of the cells.

Results

This study demonstrates that the pro-inflammatory cytokines, tumor necrosis factor alpha (TNFα) and interferon-gamma (IFNγ), induce synergistically an up-regulation of CEACAM1 expression in RWPE-1 cells, specifically favoring the CEACAM1-L isoform. Furthermore, overexpressed CEACAM1-L is associated with the deregulated expression of JAK/STAT, NFκB, and epithelial-mesenchymal transition (EMT) genes, as well as an increased cell migration.

Conclusion

We postulate that CEACAM1 isoform CEACAM1-4L may synergistically contribute to inflammation-induced oncogenesis in the prostate.

Carcinoembryonic antigen-related cell adhesion molecule 1: a key regulatory protein involved in leiomyoma growth

OBJECTIVE

To assess and characterize the role of carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) in the development of uterine leiomyoma.

DESIGN

Laboratory study.

SETTING

Academic research center.

PATIENT(S)

Not applicable.

INTERVENTION(S)

Laboratory investigation. In vitro assessment of human leiomyoma and myometrial tissue specimens as well as immortalized leiomyoma and myometrial cell lines.

MAIN OUTCOME MEASURE(S)

Western blotting and immunohistochemical analyses were performed to assess differences in CEACAM1 content between leiomyoma and myometrial samples. Small interfering RNA silencing experiments and transient transfection experiments were performed to characterize the regulatory role of CEACAM1 on downstream signaling cascades.

RESULT(S)

Analysis of RNA sequencing data revealed decreased CEACAM1 expression in human uterine leiomyoma specimens compared with that in myometrial samples. This translated to a significant down-regulation in CEACAM1 protein content in human leiomyoma compared with patient-matched myometrial tissue samples (0.236 ± 0.05-fold). A similar decrease in CEACAM1 protein content was observed in matched immortalized leiomyoma cell (ILC) and immortalized myometrial cell lines (0.21 ± 0.07). Immunohistochemical analysis revealed decreased staining intensity in leiomyoma surgical specimens compared with the matched myometrium of placebo patients. Lower CEACAM1 levels in leiomyoma were associated with increased activation of both the mitogen-activated protein kinase (MAPK) and the phosphoinositide 3-kinase/protein kinase B pathways compared with that in myometrial cells. This is significant because activation of these pathways plays an important role in leiomyoma growth. Treatment of myometrial cells with CEACAM1 small interfering RNA resulted in a significant down-regulation of CEACAM1 at the protein level (0.272 ± 0.06-fold) and was associated with increased activation of the MAPK (1.62 ± 0.21-fold) and phosphoinositide 3-kinase/protein kinase B (1.79 ± 0.35-fold) pathways, as well as increased collagen production (2.1 ± 0.49-fold). Rescue of CEACAM1 expression in leiomyoma cells by transient transfection restored regulatory control and resulted in lower activation of the MAPK pathway (0.58 ± 0.37-fold).

CONCLUSION(S)

CEACAM1 is an important protein involved in regulating many signal transduction pathways. Decreased CEACAM1 expression in leiomyoma allows permissive uncontrolled overactivation and up-regulation of downstream pathways that may contribute to leiomyoma growth.

p38γ Activation and BGP (Biliary Glycoprotein) Induction in Primates at Risk for Inflammatory Bowel Disease and Colorectal Cancer-A Comparative Study with Humans

Colorectal cancer (CRC) is a common cause of cancer-related deaths largely due to CRC liver metastasis (CRLM). Identification of targetable mechanisms continues and includes investigations into the role of inflammatory pathways. Of interest, MAPK is aberrantly expressed in CRC patients, yet the activation status is not defined. The present study assessed p38γ activation in CRC patients, cancer cells, and tissues of cotton top tamarin (CTT) and common marmoset (CM). The primate world is an overlooked resource as colitis-CRC-prone CTT are usually inure to liver metastasis while CM develop colitis but not CRC. The results demonstrate that p38γ protein and phosphorylation levels are significantly increased in CRC patients compared to normal subjects and CTT. Furthermore, p38γ phosphorylation is significantly elevated in human CRC cells and hepatoblastoma cells but not in CM colon. Additionally, carcinoembryonic antigen (CEA) and biliary glycoprotein (BGP) are induced in the CRC patients that showed p38γ phosphorylation. Inhibition of p38 MAPK in CRC cells showed a significant decline in cell growth with no effect on apoptosis or BGP level. Overall, p38γ is activated in CRC tumorigenesis and likely involves CEA antigens during CRLM in humans but not in the CTT or CM, that rarely develop CRLM.

The old CEACAMs find their new role in tumor immunotherapy

Carcinoembryonic antigen-related cell adhesion molecules (CEACAMs) contain 12 family members(CEACAM1、CEACAM3、CEACAM4、CEACAM5、CEACAM6、CEACAM7、CEACAM8、CEACAM16、CEACAM18、CEACAM19、CEACAM20 and CEACAM21)and are expressed diversely in different normal and tumor tissues. CEA (CEACAM5) has been used as a tumor biomarker since 1965. Here we review the latest research and development of the structures, expression, and function of CEACAMs in normal and tumor tissues, and their application in the tumor diagnosis, prognosis, and treatment. We focus on recent clinical studies of CEA targeted cancer immunotherapies, including bispecific antibody (BsAb) for radio-immuno-therapy and imaging, bispecific T cell engager (BiTE) and chimeric antigen receptor T cells (CAR-T). We summarize the promising clinical relevance and challenges of these approaches and give perspective view for future research. This review has important implications in understanding the diversified biology of CEACAMs in normal and tumor tissues, and their new role in tumor immunotherapy.

The role of antibody expression and their association with bladder cancer recurrence: a single-centre prospective clinical-pilot study in 35 patients

BACKGROUND

Bladder cancer (BC) is the 10th most common cancer in the UK, with about 10,000 new cases annually. About 75-85% of BC are non-muscle invasive (NMIBC), which is associated with high recurrence and progression rates (50-60% within 7-10 years). There are no routine biomarkers currently available for identifying BC patients at increased risk of developing recurrence. The focus of this research study was to evaluate antibody expression in BC patients and their association with cancer recurrence.

METHODS

35 patients scheduled for TURBT were recruited after written informed consent. Ethical approval for the project was granted via IRAS (REC4: 14/WA/0033). Following surgical procedure, tissues were preserved in 10% buffered formalin and processed within 24 h in FFPE blocks. 7 sections (4 µm each) were cut from each block and stained for CD31, Human epidermal growth factor receptor-2 (HER-2), S100P, Cyclooxygenase-2 (COX-2), VEGFR-3 thrombomodulin and CEACAM-1 using immunohistochemistry. Clinical outcome measures (obtained via cystoscopy) were monitored for up to 6 months following surgical procedure.

RESULTS

There was significantly increased expression of CD31 (p < 0.001), HER-2 (p = 0.032), S100P (p < 0.001), COX-2 (p < 0.001), VEGFR-3 (p < 0.001) and decreased expression of thrombomodulin (p = 0.010) and CEACAM-1 (p < 0.001) in bladder tumours compared to normal bladder tissues. HER-2 expression was also significantly associated with cancer grade (p = 0.003), especially between grade 1 and grade 2 (p = 0.002) and between grade 1 and grade 3 (p = 0.004). There was also a significant association between cancer stage and HER-2 expression (p < 0.001). Although recurrence was significantly associated with cancer grade, there was no association with antibody expression.

CONCLUSION

Findings from the present study may indicate an alternative approach in the monitoring and management of patients with BC. It is proposed that by allowing urological surgeons access to laboratory markers such as HER-2, Thrombomodulin and CD31 (biomarker profile), potentially, in the future, these biomarkers may be used in addition to, or in combination with, currently used scoring systems to predict cancer recurrence. However, verification and validation of these biomarkers are needed using larger cohorts.

CEACAMs serve as toxin-stimulated receptors for enterotoxigenic Escherichia coli

The enterotoxigenic Escherichia coli (ETEC) are among the most common causes of diarrheal illness and death due to diarrhea among young children in low-/middle-income countries (LMICs). ETEC have also been associated with important sequelae including malnutrition and stunting, placing children at further risk of death from diarrhea and other infections. Our understanding of the molecular pathogenesis of acute diarrheal disease as well as the sequelae linked to ETEC are still evolving. It has long been known that ETEC heat-labile toxin (LT) activates production of cAMP in the cell, signaling the modulation of cellular ion channels that results in a net efflux of salt and water into the intestinal lumen, culminating in watery diarrhea. However, as LT also promotes ETEC adhesion to intestinal epithelial cells, we postulated that increases in cAMP, a critical cellular "second messenger," may be linked to changes in cellular architecture that favor pathogen-host interactions. Indeed, here we show that ETEC use LT to up-regulate carcinoembryonic antigenrelated cell adhesion molecules (CEACAMs) on the surface of small intestinal epithelia, where they serve as critical bacterial receptors. Moreover, we show that bacteria are specifically recruited to areas of CEACAM expression, in particular CEACAM6, and that deletion of this CEACAM abrogates both bacterial adhesion and toxin delivery. Collectively, these results provide a paradigm for the molecular pathogenesis of ETEC in which the bacteria use toxin to drive up-regulation of cellular targets that enhances subsequent pathogen-host interactions.

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.

Size Matters: The Functional Role of the CEACAM1 Isoform Signature and Its Impact for NK Cell-Mediated Killing in Melanoma

Malignant melanoma is the most aggressive and treatment resistant type of skin cancer. It is characterized by continuously rising incidence and high mortality rate due to its high metastatic potential. Various types of cell adhesion molecules have been implicated in tumor progression in melanoma. One of these, the carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1), is a multi-functional receptor protein potentially expressed in epithelia, endothelia, and leukocytes. CEACAM1 often appears in four isoforms differing in the length of their extracellular and intracellular domains. Both the CEACAM1 expression in general, and the ratio of the expressed CEACAM1 splice variants appear very dynamic. They depend on both the cell activation stage and the cell growth phase. Interestingly, normal melanocytes are negative for CEACAM1, while melanomas often show high expression. As a cell–cell communication molecule, CEACAM1 mediates the direct interaction between tumor and immune cells. In the tumor cell this interaction leads to functional inhibitions, and indirectly to decreased cancer cell immunogenicity by down-regulation of ligands of the NKG2D receptor. On natural killer (NK) cells it inhibits NKG2D-mediated cytolysis and signaling. This review focuses on novel mechanistic insights into CEACAM1 isoforms for NK cell-mediated immune escape mechanisms in melanoma, and their clinical relevance in patients suffering from malignant melanoma.

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.

Characterization of murine CEACAM1 in vivo reveals low expression on CD8+ T cells and no tumor growth modulating activity by anti-CEACAM1 mAb CC1

Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) has been reported to mediate both tumorigenic and anti-tumor effects in vivo. Blockade of the CEACAM1 signaling pathway has recently been implicated as a novel mechanism for cancer immunotherapy. CC1, a mouse anti-CEACAM1 monoclonal antibody (mAb), has been widely used as a pharmacological tool in preclinical studies to inform on CEACAM1 pathway biology although limited data are available on its CEACAM1 blocking characteristics or pharmacodynamic-pharmacokinetic profiles. We sought to investigate CEACAM1 expression on mouse tumor and immune cells, characterize CC1 mAb binding, and evaluate CC1 in syngeneic mouse oncology models as a monotherapy and in combination with an anti-PD-1 mAb. CEACAM1 expression was observed at high levels on neutrophils, NK cells and myeloid-derived suppressor cells (MDSCs), while the expression on tumor-infiltrating CD8+ T cells was low. Unexpectedly, rather than blocking, CC1 facilitated binding of soluble CEACAM1 to CEACAM1 expressing cells. No anti-tumor effects were observed in CT26, MBT2 or A20 models when tested up to 30 mg/kg dose, a dose that was estimated to achieve >90% target engagement in vivo. Taken together, tumor infiltrating CD8+ T cells express low levels of CEACAM1 and CC1 Ab mediates no or minimal anti-tumor effects in vivo, as a monotherapy or in combination with anti-PD-1 treatment.

CEACAM1 promotes melanoma metastasis and is involved in the regulation of the EMT associated gene network in melanoma cells

We investigated the functional role of CEACAM1 in a spontaneous metastasis xenograft model of human melanoma in scid mice using BRAF wildtype MeWo cells with and without RNAi mediated knockdown of CEACAM1. Tumors from the xenograft model were subjected to whole genome expression analysis and metastasis was quantified histologically. Results and identified markers were verified using tissue samples of over 100 melanoma patients. Knockdown of CEACAM1 prolonged the animals' survival by significantly reducing subcutaneous growth of MeWo tumors and spontaneous lung metastasis. Microarray analysis revealed a strong influence of CEACAM1 knockdown on the network of EMT associated genes in the xenograft tumors (e.g. downregulation of BRAF, FOSL1, NRAS and TWIST). IGFBP7 and Latexin (highest up- and downregulated expression in microarray analysis) were found to be associated with longer and shorter survival, respectively, of melanoma patients. High FOSL1 and altered TWIST1 expression were found to be correlated with shortened survival in the cohort of melanoma patients. After a stepwise selection procedure combining above markers, multivariate analysis revealed IGFBP7, Latexin and altered TWIST to be prognostic markers for death. CEACAM1 could be a target for melanoma therapy as an alternative to (or in combination with) immune checkpoint and BRAF inhibitors.

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.

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.

Inhibition of cell invasion and migration by CEACAM1-4S in breast cancer

Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1), a cell-cell adhesion molecule, has been revealed to perform an important role in tumor progression. Although there are a number of studies on CEACAM1 in patients with breast cancer, there is limited information on the roles of CEACAM1 in breast cancer metastasis. The present study aimed to identify whether CEACAM1 is involved in breast cancer development and to investigate the underlying mechanisms. First, the expression of CEACAM1 was observed in patients with breast cancer, and the association between CEACAM1 expression levels and migration and invasion of breast cancer cells was analyzed. As there are 12 isoforms of CEACAM1, of which CEACAM1-4S dominates in the human breast epithelium, subsequent study focused on CEACAM1-4S as a representative of all the isoforms. Results of the present study demonstrated that CEACAM1-4S suppresses breast cancer cell invasion and migration in a manner that is dependent on the balance between matrix metalloproteinase 2/tissue inhibitor of metalloproteinase 2 and E-/N-cadherin expression. In addition, CEACAM1-4S was likely to cause reversal of epithelial-mesenchymal transition of breast cancer cells through repressing Smad2 and signal transducer and phosphorylation of activator of transcription 3. In conclusion, the present study demonstrated that CEACAM1-4S performs an inhibitory role in breast cancer metastasis, and restoring CEACAM1-4S expression may provide a novel strategy for therapy of patients with metastatic breast cancer.

Up-regulation of carcinoembryonic antigen-related cell adhesion molecule 1 in gastrointestinal cancer and its clinical relevance

Serum carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) is dysregulated in various malignant tumors and has been associated with tumor progression. However, the expression and regulatory mechanisms of serum CEACAM1 in gastrointestinal cancer are still unclear. The expression ratio of the CEACAM1-L and CEACAM1-S isoforms has seldom been investigated in gastrointestinal cancer. In this study, we intended to explore the expression and diagnostic value of CEACAM1 in gastrointestinal cancer. Serum CEACAM1 levels were measured by enzyme-linked immunosorbent assay. The protein expression and distribution of CEACAM1 in tumors were examined by immunohistochemical staining. The expression patterns and ratio of CEACAM1-L/S were analyzed by reverse transcription-polymerase chain reaction. The results showed that serum CEACAM1 levels were significantly higher in cancer patients than in healthy controls. CEACAM1 was found in secreted forms within the neoplastic glands, and its expression was more intense at the tumor invasion front. The CEACAM1-L/S (L:S) ratios were up-regulated during tumorigenesis. Our data suggest that the serum level of CEACAM1 may be used to discriminate gastrointestinal cancer patients from health controls.

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.

Co-expression of TIM-3 and CEACAM1 promotes T cell exhaustion in colorectal cancer patients

T-cell immunoglobulin domain and mucin domain-3(TIM-3) is an activation induced inhibitory molecule involved in immune tolerance and is recently reported to induce T cell exhaustion which is mediated by carcinoembryonic antigen cell adhesion molecule 1(CEACAM1), another well-known molecule expressed on activated T cells and involved in T cell inhibition. To investigate the expression of TIM-3 and CEACAM1 on circulating CD8⁺ T cells and tumor infiltrating lymphocytes (TILs), 65 diagnosed colorectal cancer (CRC) patients and 38 healthy controls were enrolled in this study and the results showed that TIM-3 and CEACAM1 were both highly expressed on circulating CD8⁺ T cells in CRC patients and elevated on TILs compared with paraneoplastic T cells. Furthermore, TIM-3⁺CEACAM1⁺ CD8⁺ T cells represented the most dysfunctional population with the least IFN-γ production. In addition, the expressions of TIM-3 and CEACAM1 were correlated with advanced stage and could be independent risk factors for CRC. We for the first time to our knowledge suggested that co-expression of TIM-3 and CEACAM1 can mediate T cell exhaustion and may be potential biomarkers for CRC prediction, highlighting the possibility of being immunotherapy targets.

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: Expression and Role in Melanocyte Transformation

Metastases represent the main cause of death in melanoma patients. Despite the current optimized targeted therapy or immune checkpoint inhibitors the treatment of metastatic melanoma is unsatisfactory. Because of the poor prognosis of advanced melanoma there is an urgent need to identify new biomarkers to differentiate melanoma cells from normal melanocytes, to stratify patients according to their risk, and to identify subgroups of patients that require close follow-up or more aggressive therapy. Furthermore, melanoma progression has been associated with the dysregulation of cell adhesion molecules. We have reviewed the literature and have discussed the important role of the expression of the carcinoembryonic antigen cell adhesion molecule 1 (CEACAM1) in the development of melanoma. Thus, novel insights into CEACAM1 may lead to promising strategies in melanoma treatment, in monitoring melanoma patients, in assessing the response to immunotherapy, and in completing the standard immunohistochemical panel used in melanoma examination.

Glycosylation Alters Dimerization Properties of a Cell-surface Signaling Protein, Carcinoembryonic Antigen-related Cell Adhesion Molecule 1 (CEACAM1)

Human carcinoembryonic antigen-related cell adhesion molecule 1 (C?/Au: EACAM1) is a cell-surface signaling molecule involved in cell adhesion, proliferation, and immune response. It is also implicated in cancer angiogenesis, progression, and metastasis. This diverse set of effects likely arises as a result of the numerous homophilic and heterophilic interactions that CEACAM1 can have with itself and other molecules. Its N-terminal Ig variable (IgV) domain has been suggested to be a principal player in these interactions. Previous crystal structures of the β-sandwich-like IgV domain have been produced using Escherichia coli-expressed material, which lacks native glycosylation. These have led to distinctly different proposals for dimer interfaces, one involving interactions of ABED β-strands and the other involving GFCC'C″ β-strands, with the former burying one prominent glycosylation site. These structures raise questions as to which form may exist in solution and what the effect of glycosylation may have on this form. Here, we use NMR cross-correlation measurements to examine the effect of glycosylation on CEACAM1-IgV dimerization and use residual dipolar coupling (RDC) measurements to characterize the solution structure of the non-glycosylated form. Our findings demonstrate that even addition of a single N-linked GlcNAc at potential glycosylation sites inhibits dimer formation. Surprisingly, RDC data collected on E. coli expressed material in solution indicate that a dimer using the non-glycosylated GFCC'C″ interface is preferred even in the absence of glycosylation. The results open new questions about what other factors may facilitate dimerization of CEACAM1 in vivo, and what roles glycosylation may play in heterophylic interactions.

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.

SOX9 indirectly regulates CEACAM1 expression and immune resistance in melanoma cells

As melanoma cells are immunogenic, they instigate an adaptive immune response and production of anti-tumor T-cells. A central factor in this interaction is CEACAM1 (carcinoembryonic antigen cell adhesion molecule 1), a transmembrane glycoprotein previously shown in our lab to protect melanoma cells from T cell-mediated killing. In this study, we examine the role of transcription factor SOX9 in the regulation of CEACAM1 expression and immune resistance in melanoma cells. Knockdown of endogenous SOX9 results in CEACAM1 up-regulation, while its overexpression leads to the opposite effect. We show that SOX9 controls CEACAM1 expression at a transcriptional level, but in an indirect manner, as regulation of the CEACAM1 promoter remains intact even when all eight potential SOX9-binding sites are abolished. A series of promoter truncations localizes the SOX9-controlled area to the proximal 200bp of the promoter. Point mutations in putative Sp1 and ETS1 binding sites identify these transcription factors as the primary SOX9-controlled mediators. Co-immunoprecipitation studies show that SOX9 and Sp1 physically interact in melanoma cells, while silencing of SOX9 down-regulates ETS1, but not Sp1, in the same cells. Finally, knockdown of SOX9 indeed renders melanoma cells resistant to T cell-mediated killing, in line with the increased CEACAM1 expression. In conclusion, we show that SOX9 regulates CEACAM1 expression in melanoma cells, and thereby their immune resistance. As CEACAM1 is a pivotal protein in melanoma biology and immune crosstalk, further understanding of its regulation can provide new insights and contribute to the development of novel approaches to therapy.

Kaposi's Sarcoma-Associated Herpesvirus Interleukin-6 Modulates Endothelial Cell Movement by Upregulating Cellular Genes Involved in Migration

Kaposi’s sarcoma-associated herpesvirus (KSHV) is the causative agent of human Kaposi’s sarcoma, a tumor that arises from endothelial cells, as well as two B cell lymphoproliferative diseases, primary effusion lymphoma and multicentric Castleman’s disease. KSHV utilizes a variety of mechanisms to evade host immune responses and promote cellular transformation and growth in order to persist for the life of the host. A viral homolog of human interleukin-6 (hIL-6) named viral interleukin-6 (vIL-6) is encoded by KSHV and expressed in KSHV-associated cancers. Similar to hIL-6, vIL-6 is secreted, but the majority of vIL-6 is retained within the endoplasmic reticulum, where it can initiate functional signaling through part of the interleukin-6 receptor complex. We sought to determine how intracellular vIL-6 modulates the host endothelial cell environment by analyzing vIL-6’s impact on the endothelial cell transcriptome. vIL-6 significantly altered the expression of many cellular genes associated with cell migration. In particular, vIL-6 upregulated the host factor carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) at the protein and message levels. CEACAM1 has been implicated in tumor invasion and metastasis and promotes migration and vascular remodeling in endothelial cells. We report that vIL-6 upregulates CEACAM1 by a STAT3-dependent mechanism and that CEACAM1 promotes vIL-6-mediated migration. Furthermore, latent and de novo KSHV infections of endothelial cells also induce CEACAM1 expression. Collectively, our data suggest that vIL-6 modulates endothelial cell migration by upregulating the expression of cellular factors, including CEACAM1.

Kaposi’s sarcoma-associated herpesvirus (KSHV) is linked with the development of three human malignancies, Kaposi’s sarcoma, multicentric Castleman’s disease, and primary effusion lymphoma. KSHV expresses many factors that enable the virus to manipulate the host environment in order to persist and induce disease. The viral interleukin-6 (vIL-6) produced by KSHV is structurally and functionally homologous to the human cytokine interleukin-6, except that vIL-6 is secreted slowly and functions primarily from inside the host cell. To investigate the unique intracellular role of vIL-6, we analyzed the impact of vIL-6 on endothelial cell gene expression. We report that vIL-6 significantly alters the expression of genes associated with cell movement, including that for CEACAM1. The gene for CEACAM1 was upregulated by vIL-6 and by latent and primary KSHV infection and promotes vIL-6-mediated endothelial cell migration. This work advances the field’s understanding of vIL-6 function and its contribution to KSHV pathogenesis.

Serum CEACAM1 Elevation Correlates with Melanoma Progression and Failure to Respond to Adoptive Cell Transfer Immunotherapy

Malignant melanoma is a devastating disease whose incidences are continuously rising. The recently approved antimelanoma therapies carry new hope for metastatic patients for the first time in decades. However, the clinical management of melanoma is severely hampered by the absence of effective screening tools. The expression of the CEACAM1 adhesion molecule on melanoma cells is a strong predictor of poor prognosis. Interestingly, a melanoma-secreted form of CEACAM1 (sCEACAM1) has recently emerged as a potential tumor biomarker. Here we add novel evidences supporting the prognostic role of serum CEACAM1 by using a mice xenograft model of human melanoma and showing a correlation between serum CEACAM1 and tumor burden. Moreover, we demonstrate that serum CEACAM1 is elevated over time in progressive melanoma patients who fail to respond to immunotherapy as opposed to responders and stable disease patients, thus proving a correlation between sCEACAM1, response to treatment, and clinical deterioration.

P4H9-detected molecule expression on spindle-shaped fibroblasts indicates malignant phenotype of colorectal cancer

BACKGROUND

Our previous study using a mammary fat pad mouse model showed that P4H9, produced by the β2 integrin epitope, detected a molecule on fibroblasts in response to carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1)-expressing cancer cells. P4H9-detected molecule (PDM) expression appeared to be associated with myofibroblast differentiation. In this study, we investigated whether PDM is expressed on fibroblasts and cancer cells in clinical tissue samples, and whether the presence of PDM-expressing colorectal cancer cells is correlated with clinicopathological features of patients.

METHODS

Immunohistochemistry was conducted to detect P4H9 on clinical tissue samples from 156 patients with colorectal cancer. Risk factors for metastases and survival were calculated for clinical implication of PDM-expressing spindle-shaped fibroblasts.

RESULTS

Multivariate analysis showed that PDM-expressing spindle-shaped fibroblasts were an independent risk factor for lymph node metastasis, hematogenous metastasis, and poor survival. A Kaplan-Meier survival curve indicated that PDM-expressing spindle-shaped fibroblasts were associated with shorter survival time (P<0.0001). Immunofluorescence showed PDM expression on CCD-18Co fibroblasts and two colorectal cancer cell lines (HCT116 and HCT-15).

CONCLUSIONS

PDM-expressing spindle-shaped fibroblasts are associated with metastasis and shorter survival in colorectal cancer patients. PDM-expressing spindle-shaped fibroblasts may have a role in eliciting the malignant phenotype of colorectal cancer.

MITF is a critical regulator of the carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) in malignant melanoma

The multifunctional Ig-like carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) is neo-expressed in the majority of malignant melanoma lesions. CEACAM1 acts as a driver of tumor cell invasion, and its expression correlates with poor patient prognosis. Despite its importance in melanoma progression, how CEACAM1 expression is regulated is largely unknown. Here, we show that CEACAM1 expression in melanoma cell lines and melanoma tissue strongly correlates with that of the microphthalmia-associated transcription factor (MITF), a key regulator of melanoma proliferation and invasiveness. MITF is revealed as a direct and positive regulator for CEACAM1 expression via binding to an M-box motif located in the CEACAM1 promoter. Taken together, our study provides novel insights into the regulation of CEACAM1 expression and suggests an MITF-CEACAM1 axis as a potential determinant of melanoma 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.

Negative immune checkpoints on T lymphocytes and their relevance to cancer immunotherapy

The term 'inhibitory checkpoint' refers to the broad spectrum of co-receptors expressed by T cells that negatively regulate T cell activation thus playing a crucial role in maintaining peripheral self-tolerance. Co-inhibitory receptor ligands are highly expressed by a variety of malignancies allowing evasion of anti-tumour immunity. Recent studies demonstrate that manipulation of these co-inhibitory pathways can remove the immunological brakes that impede endogenous immune responses against tumours. Antibodies that block the interactions between co-inhibitory receptors and their ligands have delivered very promising clinical responses, as has been shown by recent successful trials targeting the CTLA-4 and PD-1 pathways. In this review, we discuss the mechanisms of action and expression pattern of co-inhibitory receptors on different T cells subsets, emphasising differences between CD4(+) and CD8(+) T cells. We also summarise recent clinical findings utilising immune checkpoint blockade.

CEACAM1-4L Promotes Anchorage-Independent Growth in Melanoma

Widespread metastasis is the leading course of death in many types of cancer, including malignant melanoma. The process of metastasis can be divided into a number of complex cell biological events, collectively termed the “invasion-metastasis cascade.” Previous reports have characterized the capability of anchorage-independent growth of cancer cells in vitro as a key characteristic of highly aggressive tumor cells, particularly with respect to metastatic potential. Biological heterogeneity as well as drastic alterations in cell adhesion of disseminated cancer cells support escape mechanisms for metastases to overcome conventional therapies. Here, we show that exclusively the carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) splice variant CEACAM1-4L supports an anchorage-independent signature in malignant melanoma. These results highlight important variant-specific modulatory functions of CEACAM1 for metastatic spread in patients suffering malignant melanoma.

CEACAM1-3S Drives Melanoma Cells into NK Cell-Mediated Cytolysis and Enhances Patient Survival

CEACAM1 is a widely expressed multifunctional cell-cell adhesion protein reported to serve as a poor prognosis marker in melanoma patients. In this study, we examine the functional and clinical contributions of the four splice isoforms of CEACAM1. Specifically, we present in vitro and in vivo evidence that they affect melanoma progression and immune surveillance in a negative or positive manner that is isoform specific in action. In contrast with isoforms CEACAM1-4S and CEACAM1-4L, expression of isoforms CEACAM1-3S and CEACAM1-3L is induced during disease progression shown to correlate with clinical stage. Unexpectedly, overall survival was prolonged in patients with advanced melanomas expressing CEACAM1-3S. The favorable effects of CEACAM1-3S related to enhanced immunogenicity, which was mediated by cell surface upregulation of NKG2D receptor ligands, thereby sensitizing melanoma cells to lysis by natural killer cells. Conversely, CEACAM1-4L downregulated cell surface levels of the NKG2D ligands MICA and ULBP2 by enhanced shedding, thereby promoting malignant character. Overall, our results define the splice isoform-specific immunomodulatory and cell biologic functions of CEACAM1 in melanoma pathogenesis.

CEACAM1 and hollow spheroid formation modulate the chemosensitivity of colorectal cancer to 5-fluorouracil

PURPOSE

Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) re-expressed and promoted hollow spheroid (HS) formation beyond the invasion front of colorectal cancer. The aim of the present study was to clarify whether CEACAM1 cytoplasmic domain isoform balance and HS are associated with resistance to 5-fluorouracil (5FU).

METHODS

Two-dimensional (D) or 3D culture systems were employed to evaluate the effects of CEACAM1 cytoplasmic isoform balance and HS formation on the chemosensitivity of colorectal cancer cells to 5FU. The risk factors for postoperative recurrence were calculated based on the presence of HS and various clinicopathological characteristics in 82 patients with Stage III colorectal cancer who had undergone curative surgery followed by 5FU-based chemotherapy.

RESULTS

CEACAM1-4L-transfected HT29 and CEACAM1-4L and 4S expressing parental LS174T cells had significantly higher resistance to 5FU in comparison with CEACAM1-4S- or vector control-transfected cells. In 3D culture, HS formation induced by CEACAM1-4L induced chemoresistance to 5FU, whereas the solid spheres formed in response to CEACAM1-4S were destroyed by 5FU treatment. HS was identified as an independent factor for recurrence of Stage III colorectal cancer after curative resection followed by 5FU-based chemotherapy. Kaplan-Meier survival curves demonstrated that patients with HS had lower recurrence-free survival rate.

CONCLUSIONS

CEACAM1 long cytoplasmic domain isoform dominance and HS formation are phenotypes associated with chemoresistance to 5FU.

CEACAM1 long cytoplasmic domain isoform is associated with invasion and recurrence of hepatocellular carcinoma

BACKGROUND

The two isoforms of carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1), 1 with a long cytoplasmic domain (CEACAM1-L) and 1 with a short (CEACAM1-S), are involved in different signaling pathways. β2-spectrin (β2SP) is an adaptor protein that plays critical roles in the proper control of Smad access to activate receptors involved in regulation of TGF-β signaling. In this study, we examined the association between CEACAM1 isoform balance and hepatocellular carcinoma (HCC) malignant potential and investigated the possibility of a molecular interaction between CEACAM1 and β2SP.

METHODS

Immunohistochemical analysis was carried out with CEACAM1-L or CEACAM1-S antibodies on 154 HCC tissues to correlate with the factors of malignancy. Invasion assay was performed for the effect of CEACAM1 expression on HCC cell lines. Moreover, immunohistochemical analysis and immunoprecipitation analysis were performed to investigate the association between CEACAM1 isoform balance and β2SP.

RESULTS

In immunohistochemical analysis, CEACAM1-L expression dominance was a risk factor for HCC recurrence (p = 0.04) and was significantly associated with a shorter survival compared with CEACAM1-S expression dominance. Invasion assay indicated that CEACAM1-4L-transfected HLF and PLC/PRF/5 cells showed significantly increased invasion (p < 0.0001) and CEACAM1-4S-transfected HLF cells showed significantly decreased invasion. Immunohistochemical analysis of β2SP suggested that the HCCs with CEACAM1-L-dominant expression were more strongly stained with β2SP than the HCCs with CEACAM1-S-dominant expression (p = 0.013), and coprecipitation assays indicated that CEACAM1-L could bind to β2SP.

CONCLUSIONS

CEACAM1-L may enhance the HCC invasiveness through an interaction with β2SP and subsequent effects on TGF-β signaling.

Insights into significant pathways and gene interaction networks underlying breast cancer cell line MCF-7 treated with 17β-estradiol (E2)

OBJECTIVE

Estrogens are known to regulate the proliferation of breast cancer cells and to alter their cytoarchitectural and phenotypic properties, but the gene networks and pathways by which estrogenic hormones regulate these events are only partially understood.

METHODS

We used global gene expression profiling by Affymetrix GeneChip microarray analysis, with KEGG pathway enrichment, PPI network construction, module analysis and text mining methods to identify patterns and time courses of genes that are either stimulated or inhibited by estradiol (E2) in estrogen receptor (ER)-positive MCF-7 human breast cancer cells.

RESULTS

Of the genes queried on the Affymetrix Human Genome U133 plus 2.0 microarray, we identified 628 (12h), 852 (24h) and 880 (48 h) differentially expressed genes (DEGs) that showed a robust pattern of regulation by E2. From pathway enrichment analysis, we found out the changes of metabolic pathways of E2 treated samples at each time point. At 12h time point, the changes of metabolic pathways were mainly focused on pathways in cancer, focal adhesion, and chemokine signaling pathway. At 24h time point, the changes were mainly enriched in neuroactive ligand-receptor interaction, cytokine-cytokine receptor interaction and calcium signaling pathway. At 48 h time point, the significant pathways were pathways in cancer, regulation of actin cytoskeleton, cell adhesion molecules (CAMs), axon guidance and ErbB signaling pathway. Of interest, our PPI network analysis and module analysis found that E2 treatment induced enhancement of PRSS23 at the three time points and PRSS23 was in the central position of each module. Text mining results showed that the important genes of DEGs have relationship with signal pathways, such as ERbB pathway (AREG), Wnt pathway (NDP), MAPK pathway (NTRK3, TH), IP3 pathway (TRA@) and some transcript factors (TCF4, MAF).

CONCLUSIONS

Our studies highlight the diverse gene networks and metabolic and cell regulatory pathways through which E2 operates to achieve its widespread effects on breast cancer cells.

CEACAM1 expression in oligodendrocytes of the developing rat brain shows a spatiotemporal relation to myelination and is altered in a model of encephalopathy of prematurity

CEACAM1 is the founder molecule of the family of 'carcinoembryonic antigen-related cell adhesion molecules' and part of the immunoglobulin superfamily. Due to its role as a coreceptor to many other receptors (e.g. Toll-like receptor 2, Toll-like receptor 4, T-cell receptor, B-cell receptor, epidermal growth factor receptor and vascular endothelial growth factor receptor) and its different isoforms, CEACAM1 is a multifunctional protein with an impact on proliferation and differentiation of multiple cell types. Although different modes of action in other tissues are described, the role of CEACAM1 in the developing brain remains elusive. Here we report for the first time that CEACAM1 is expressed ontogenetically in oligodendrocytes of the developing rat brain, and that CEACAM1 expression has a spatiotemporal relation to myelination. In addition, CEACAM1 expression is altered in a model of hyperoxia- and inflammation-induced encephalopathy of prematurity, a myelination disorder of children born preterm. Furthermore, primary oligodendrocytes stimulated with CEACAM1 show increased myelination. Therefore, we postulate that CEACAM1 is, at least in part, involved in hyperoxia- and inflammation-induced disruption of myelination, but may also play a role in intact myelination as it is ontogenetically expressed in myelinating oligodendrocytes.

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.

MDR-1-overexpression in HT 29 colon cancer cells grown in SCID mice

The multidrug-resistance 1 (MDR-1) P-glycoprotein (Pgp) is a transmembrane transporter system, which actively pumps cytotoxic drugs out of the cell. MDR-1 acquired in vitro differs from MDR-1 acquired in vivo, but has important consequences on the cellular phenotype and metastatic behavior. Here we report that the human colonic cancer cell line HT29 (MDR-1 negative) is more malignant than its MDR-1 overexpressing variant (HT29 MDR-1 positive). HT29 MDR-1 negative cells produce undifferentiated signet ring carcinomas when implanted subcutaneously into SCID mice, while HT29 MDR-1 positive cells form tumors with tubular structures, but without signet ring cells. Immunohistochemical proliferation marker analysis revealed that the MDR-1 positive cells proliferate much more slowly than the MDR-1 negative cells. MDR-1 overexpression results in a less differentiated phenotype at the cellular level (absence of mucin producing cells) but in a more differentiated phenotype at the tissue level (tubule formation). In addition, lectin binding patterns including that of Helix pomatia agglutinin (HPA), an indicator of metastatic potential, differed between the two cell lines. HT29 MDR-1 positive cells had less HPA binding sites than HT29 MDR-1 negative counterparts and metastasized less frequently in SCID mice. As slow proliferation, low degree of differentiation and multidrug-resistance is a hallmark of cancer stem cells and all were present in MDR-1 positive tumors, it is attractive to speculate that they represent a stem cell rich tumor. As shown by global gene expression analyses, genes involved, e.g. in cell adhesion, glycosylation and signal transduction, were deregulated in MDR-1 positive tumors compared to MDR-negative tumors. Overexpression of E-cadherin and carcinoembryonic antigen-related cell adhesion molecules 1 (CEACAM1) may provide clues to the mechanisms responsible for the reduced metastatic potential of MDR-1 overexpressing tumors. Since drug treatment shifted the cells towards a less metastatic phenotype in this in vivo model, it seems conceivable to achieve this using drug treatment also in a clinical situation.

Loss of expression of the tumor suppressor CEACAM1 links different hereditary colorectal carcinoma subtypes to the genesis of sporadic colorectal carcinoma

According to their carcinogenesis, colorectal cancer (CRC) subtypes show distinct molecular parameters. Hereditary non-polypous colorectal cancer (HNPCC) is the most common inherited CRC characterized by clinical criteria and confirmed microsatellite instability (MSI). Interestingly, a recently identified subtype, familial colorectal cancer type X (FCC-X), shows the same clinical criteria but microsatellite stability (MSS). CEACAM1 is a known tumor suppressor that regulates apoptosis in colon cells, and its loss is one of the most frequent events in early tumorigenesis of CRC. Therefore its loss may characterize precursor colon cells prior to neoplastic transformation. We analyzed tumor specimens of HNPCC and FCC-X patients in order to investigate whether there is a loss of CEACAM1 expression analogous to sporadic CRC and whether the expression of CEACAM1 would distinguish between these tumor entities. No differences in CEACAM1 expression were noted between HNPPC (n = 38) and FCC-X (n = 30) tumors. CEACAM1 was reduced in near-identical frequencies in 36/38 (95%) HNPCC and 29/30 (97%) FCC-X. This is the first report to demonstrate the loss of CEACAM1 expression in hereditary CRC. There was no difference between HNPCC and FCC-X. The frequency of expression loss was comparable to sporadic CRC, indicating that loss of CEACAM1 is an early event in colorectal tumorigenesis linking the genesis of sporadic and hereditary CRC.

Overexpression and clinical significance of carcinoembryonic antigen-related cell adhesion molecule 6 in colorectal cancer

BACKGROUND

Carcinoembryonic antigen-related cell adhesion molecule 6 (CEACAM6) inhibits anoikis and affects the malignant phenotype of cancer cells. In this study, we analyzed CEACAM6 as a gene that is highly upregulated in colon cancer tissues, and examined the assertion that CEACAM6 might be a suitable candidate tumor marker for the diagnosis of colon cancer.

METHODS

CEACAM6 gene expression in human colon tissues was performed by tissue microarray and analyzed using RT-PCR (each of normal and tumor tissue, n=40) and immunohistochemical and clinicopathological (colon cancer patients, n=143) analyses.

RESULTS

CEACAM6 transcriptional and translational levels were significantly upregulated in human tumor tissues compared to non-tumor regions, and clinicopathological analysis revealed a significant correlation between CEACAM6 protein expression and Dukes' stage (p<0.001). High expression levels of CEACAM6 were significantly associated with lower overall survival (p<0.001) and shorter recurrence-free survival (p<0.001). We demonstrated that knockdown of CEACAM6 with CEACAM6-specific small interfering RNA in colorectal cancer cells attenuated invasivity (35%); conversely, the overexpression of CEACAM6 increased invasiveness.

CONCLUSIONS

CEACAM6 is significantly upregulated in colon cancer tissues and is closely associated with poor prognosis, indicating that CEACAM6 might be used as a tumor biomarker and a potential therapeutic target for colon cancer.

Host-related carcinoembryonic antigen cell adhesion molecule 1 promotes metastasis of colorectal cancer

Liver metastasis is the predominant cause of colorectal cancer (CRC)-related mortality in developed countries. Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) is a cell adhesion molecule with reduced expression in early phases of CRC development and thus functions as a tumor growth inhibitor. However, CEACAM1 is upregulated in metastatic colon cancer, suggesting a bimodal role in CRC progression. To investigate the role of this protein in the host metastatic environment, Ceacam1(-/-) mice were injected intrasplenically with metastatic MC38 mouse CRC cells. A significant reduction in metastatic burden was observed in Ceacam1(-/-) compared with wild-type (WT) livers. Intravital microscopy showed decreased early survival of MC38 cells in Ceacam1(-/-) endothelial environment. Metastatic cell proliferation within the Ceacam1(-/-) livers was also diminished. Bone marrow-derived cell recruitment, attenuation of immune infiltrates and diminished CCL2, CCL3 and CCL5 chemokine production participated in the reduced Ceacam1(-/-) metastatic phenotype. Transplantations of WT bone marrow (BM) into Ceacam1(-/-) mice fully rescued metastatic development, whereas Ceacam1(-/-) BM transfer into WT mice showed reduced metastatic burden. Chimeric immune cell profiling revealed diminished recruitment of CD11b(+)Gr1(+) myeloid-derived suppressor cells (MDSCs) to Ceacam1(-/-) metastatic livers and adoptive transfer of MDSCs confirmed the involvement of these immune cells in reduction of liver metastasis. CEACAM1 may represent a novel metastatic CRC target for treatment.

Tumor angiogenesis mediated by myeloid cells is negatively regulated by CEACAM1

Bv8 (prokineticin 2) expressed by Gr1(+)CD11b(+) myeloid cells is critical for VEGF-independent tumor angiogenesis. Although granulocyte colony-stimulating factor (G-CSF) has been shown to be a key inducer of Bv8 expression, the basis for Bv8 production in driving tumor angiogenesis is undefined. Because the cell adhesion molecule CEACAM1, which is highly expressed on Gr1(+)CD11b(+) myeloid cells, is known to regulate G-CSF receptor (G-CSFR) signaling, we hypothesized that CEACAM1 would regulate Bv8 production in these cells. In support of this hypothesis, we found that Bv8 expression was elevated in Gr1(+)CD11b(+) cells from Ceacam1-deficient mice implanted with B16 melanoma, increasing the infiltration of Gr1(+)CD11b(+) myeloid cells in melanoma tumors and enhancing their growth and angiogenesis. Furthermore, treatment with anti-Gr1 or anti-Bv8 or anti-G-CSF monoclonal antibody reduced myeloid cell infiltration, tumor growth, and angiogenesis to levels observed in tumor-bearing wild-type (WT) mice. Reconstitution of CEACAM1-deficient mice with WT bone marrow cells restored tumor infiltration of Gr1(+)CD11b(+) cells along with tumor growth and angiogenesis to WT levels. Treatment of tumor-bearing WT mice with anti-CEACAM1 antibody limited tumor outgrowth and angiogenesis, albeit to a lesser extent. Tumor growth in Ceacam1-deficient mice was not affected significantly in Rag(-/-) background, indicating that CEACAM1 expression in T and B lymphocytes had a negligible role in this pathway. Together, our findings show that CEACAM1 negatively regulates Gr1(+)CD11b(+) myeloid cell-dependent tumor angiogenesis by inhibiting the G-CSF-Bv8 signaling pathway.

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.