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Carcinoembryonic antigen (CEA) is a tumor marker that is associated with metastasis, poor response to chemotherapy of colorectal cancer (CRC), and anoikis, a form of apoptosis caused by cell detachment from matrix that is dependent on TRAIL-R2 (DR5) and caspase-8 activation in CRC. Although CEA is a homophilic binding protein that may provide survival signals through homotypical cell aggregation, we now report that CEA binds TRAIL-R2 (DR5) directly in two-hybrid assays to decrease anoikis through the extrinsic pathway. Deletion of the PELPK sequence (delPELPK) of CEA (delPELPK CEA) restores sensitivity to anoikis while it maintains its cell aggregation function. Wild-type (WT) CEA also increases experimental hepatic metastasis, whereas the delPELPK CEA does not. Thus, membrane CEA interacts with DR5 to inhibit anoikis and increase metastatic potential in CRC.

Most circulating tumor cells die within 24 h of entering the hepatic microvasculature because their arrest initiates an ischemia-reperfusion (I/R) injury that is cytotoxic. Human colorectal carcinomas (CRC) produce the glycoprotein Carcinoembryonic Antigen (CEA) that increases experimental liver metastasis in nude mice. Since CEA induces release of IL-6 and IL-10, we hypothesized that CEA inhibits the I/R injury through a Kupffer cell-mediated cytokine-dependent pathway. We assessed cytokine effects in CRC co-cultured with liver and in vivo. Human CRC prelabeled with fluorescent dyes were incubated with a reoxygenated suspension of ischemic nude mouse liver fragments in a bioreactor. CEA, rhIL-6 or rhIL-10 were either administered to the donor mice prior to hepatic ischemia or during co-culture. Liver donors were athymic nude or iNOS, IL-6 or IL-10 knock out mice. Ischemic-reoxygenated liver kills Clone A CRC through production of nitric oxide (NO) and superoxide anion. Treatment of liver donors with CEA prior to hepatic ischemia inhibited this in vitro cytotoxicity through an IL-10 and Kupffer cell dependent pathway that inhibited NF-kappaB activation, NO production and iNOS upregulation. IL-10 but not IL-6 enhanced CRC survival in nude mouse liver in vivo. Thus, CEA enhanced metastasis by inducing IL-10 to inhibit iNOS upregulation in host liver.

Background: Interleukin-6 (IL-6) is an important proinflammatory cytokine that has multiple effects on stimulating inflammation and cell growth. Experimental data suggest that carcinoembryonic antigen (CEA) induces the systemic production of IL-6 and that IL-6 may stimulate tumor cell growth at metastatic sites. We tested the hypothesis that blood concentrations of IL-6 are associated with the amount of circulating CEA and with prognosis in patients with colorectal cancer., Methods: CEA and IL-6 concentrations were measured by using enzyme immunoassay in preoperative serum samples from 208 patients with stages I through IV colorectal cancer., Results: Linear regression analysis showed a significant association between serum values of CEA and IL-6 (r = .544; R2 = .296; P < .001). Patients with stage III and stage IV disease had a significantly higher IL-6 serum concentration than those with stage I and stage II disease. In patients with stages I through III, 5-year survival was 83% in cases with concentrations of IL-6 at 10 pg/ml or less (n = 94) and 56% in cases with IL-6 concentrations of more than 10 pg/ml (n = 54; P = .001; median follow-up time, 46 months). By using multivariate analysis, an IL-6 concentration of more than 10 pg/ml was an independent prognostic factor of survival (relative risk = 1.820; P = .020)., Conclusions: In patients with colorectal cancer, blood concentration of IL-6 is associated with high circulating CEA and advanced stage. Furthermore, an IL-6 concentration of more than 10 pg/ml is an independent negative prognostic marker of survival.

Carcinoembryonic antigen (CEA) injected intravenously into athymic nude mice increases the ability of weakly metastatic human colorectal carcinoma (CRC) cells to colonize liver in an experimental metastasis assay. Since CEA acts as an intercellular adhesion molecule in vitro, several investigators have postulated that this facilitation of experimental metastasis may be mediated through adhesion between CEA on CRC and CEA-binding proteins on Kupffer or other cells lining the hepatic sinusoid. The present work tested this postulate both by intravital fluorescence videomicroscopy in vivo and in adhesion assays in vitro to enriched populations of Kupffer cells and hepatic sinusoidal endothelial cells (SEC). The data indicate that CEA expression does not effect adhesion to enriched Kupffer cells or SEC in vitro. These data suggest that CEA enhances liver colonization through another mechanism, possibly one that involves modulation of the hepatic response to tumor cell implantation.

Carcinoembryonic antigen (CEA) may promote experimental metastasis through production of cytokines. The effect of systemic CEA on the production of proinflammatory cytokines was investigated in mice and compared to levels induced by lipopolysaccharide (LPS). Serum concentrations of interleukin (IL)-6 peaked 1 h after an i.v. CEA injection of 40 microg/mouse to 37-54% of the maximal level induced by a 1 microg/mouse injection of LPS in both normal and immunoincompetent mice. The CEA induction of IL-6 was a specific response, because the peptide PELPK (the pentapeptide on CEA that is the ligand for the CEA receptor on Kupffer cells) conjugated to albumin induced 30% of the maximal CEA response for IL-6, whereas the specificity control PELGK-conjugated albumin did not. IL-1alpha and tumor necrosis factor (TNF)-alpha levels after i.v. injection of CEA were only 3-5% of those induced by LPS. The IL-6 responses of mice pretreated with 100 microg/kg genistein were decreased by more than 40%. However, genistein inhibited the TNF-alpha response to LPS by 46% but increased the CEA-induced response by 300%. When murine Kupffer cells were stimulated with LPS or CEA in vitro, LPS increased tyrosine phosphorylation of a Mr 30,000 protein, whereas CEA decreased phosphorylation of a Mr 60,000 protein and did not increase phosphorylation of the Mr 30,000 protein. Thus, i.v. CEA stimulates production of IL-6 and TNF-alpha after binding to Kupffer cells through signal transduction pathways that appear to be different from those stimulated by LPS.

MIP-101 is a poorly differentiated human colon carcinoma cell line established from ascites that produces minimal amounts of carcinoembryonic antigen (CEA), a 180 kDa glycoprotein tumor marker, and nonspecific cross-reacting antigen (NCA), a related protein that has 50 and 90 kDa isoforms, in monolayer culture. However, MIP-101 produces CEA when implanted into the peritoneum of nude mice but not when implanted into subcutaneous tissue. We tested whether three-dimensional (3D) growth was a sufficient stimulus to produce CEA and NCA 50/90 in MIP-101 cells, because cells grow in 3D in vivo rather than in two-dimensions (2D) as occurs in monolayer cultures. To do this, MIP-101 cells were cultured on microcarrier beads in 3D cultures, either in static cultures as nonadherent aggregates or under dynamic conditions in a NASA-designed low shear stress bioreactor. MIP-101 cells proliferated well under all three conditions and increased CEA and NCA production three- to four-fold when grown in 3D cultures compared to MIP-101 cells growing logarithmically in monolayers. These results suggest that 3D growth in vitro simulates tumor function in vivo and that 3D growth by itself may enhance production of molecules that are associated with the metastatic process.

Carcinoembryonic antigen (CEA) has been shown to increase the metastatic potential of some human colorectal cancer cell lines. To investigate further the mechanisms involved we have produced three clones (6, 8 and 17) from the poorly differentiated human colorectal cancer cell line MIP-101 that have been transfected with the full length cDNA encoding for human carcinoembryonic antigen (CEA). They produce CEA with a mol. wt. of 180000 by Western blotting and secrete it into the culture medium. Clone 6 is a high CEA producer, clones 8 and 17 are intermediate producers. The doubling time for clone 8 was similar to that of the parent cell line while clones 6 and 17 had doubling times nearly twice that of the parent cells. These clones are tumorigenic when injected subcutaneously in nude mice are positive for CEA by immunoperoxidase staining and the mice have elevated blood levels of CEA. Clone 6 formed large aggregates in culture while clone 17 formed smaller aggregates. Clone 8 behaved like the parent cell line with rare cell/cell contact. Clones 6 and 17 also adhered to CEA coated plastic while clone 8, a neo-transfected control and the parent cell line did not. A significant increase in the incidence of hepatic tumors was observed with clone 6 (P < 0.01) and clone 17 (P < 0.02) following intrasplenic injection into nude mice. Immunohistopathology of the hepatic tumors showed strong CEA staining from clones 6 and 17 with weak staining from clone 8. The parent cell line was negative for CEA as were the neo-transfected controls. Of the neo controls none of 10 had liver colonies. Mice injected with clone 6 which developed liver metastasis had the highest plasma levels of CEA (37.3 +/- 8.8 ng/ml). We observed strong CEA staining in Kupffer cells in the normal liver adjacent to the CEA producing tumors. This study provides further evidence for the involvement of CEA in the metastatic process.

Galectin-1 and galectin-3, galactoside-binding lectins with molecular weights of M(r) 14,500 and 31,000, respectively, are expressed in normal and malignant cells and have been implicated in regulation of cell growth, adhesion, and metastasis. We analyzed the expression of galectins in 21 cultured human colon carcinoma cell lines by immunoblotting. Galectin-1 was detected in only 7, whereas galectin-3 was found in 20 of the cell lines. KM12 cells, which express only galectin-3, were used to isolate this lectin by affinity chromatography, and the purified lectin was used to identify complementary glycoconjugates by blotting. Galectin-3 was shown to bind to human laminin, carcinoembryonic antigen, and lysosome-associated membrane glycoproteins, which are involved in cell adhesion. Galectin-3 was localized on the KM12 cell surface and colocalized with carcinoembryonic antigen. Several endogenous glycoproteins and cell surface proteins of molecular weights in the range M(r) 58,000 to > 200,000, including carcinoembryonic antigen and lysosome-associated membrane glycoproteins, were identified as galectin-3 ligands by coimmunoprecipitation with and affinity chromatography on immobilized galectin-3. These data demonstrate that galectin-3 interacts with several adhesion molecules and suggest that this lectin may have a role in human colon carcinoma cell adhesion.

Background/aims: Human colorectal carcinoma cells bind to collagen and laminin in the basement membrane as well as to carcinoembryonic antigen (CEA) on neighboring cells. The purpose of this study was to determine whether normal colonic epithelial cells bind to CEA, collagen, or laminin., Methods: Intact colonic crypts were isolated from normal mucosa in 13 specimens resected for colorectal carcinoma or colonic diverticulitis. Colonocytes were released from the crypts by treatment with collagenase and deoxyribonuclease and tested for adhesion to CEA, type IV collagen, and laminin in a solid-phase adhesion assay., Results: Twelve percent to 25% of colonocytes in all specimens bound to CEA. Colonocytes from seven specimens also bound to type IV collagen, but none of the colonocyte preparations bound significantly to laminin. Monoclonal antibodies to CEA and to the hyaluronate receptor CD44 and enzymatic removal of membrane CEA blocked the adhesion of colonocytes to CEA., Conclusions: First, colonocytes use the same epitopes on CEA and CD44 as colorectal carcinoma cells to adhere to solid-phase CEA. Second, colonocytes bind to solid-phase CEA through CEA-to-CEA homophilic binding. Third, CEA and type IV collagen, but not laminin, are adhesion ligands for human colonocytes.

Microgravity has advantages for the cultivation of tissues with high fidelity; however, tissue formation requires cellular recognition and adhesion. We tested the hypothesis that simulated microgravity does not affect cell adhesion. Human colorectal carcinoma cells were cultured in the NASA Rotating Wall Vessel (RWV) under low shear stress with randomization of the gravity vector that simulates microgravity. After 6-7 days, cells were assayed for binding to various substrates and compared to cells grown in standard tissue culture flasks and static suspension cultures. The RWV cultures bound as well to basement membrane proteins and to CEA, an intercellular adhesion molecule, as control cultures did. Thus, microgravity does not alter epithelial cell adhesion and may be useful for tissue engineering.

Carcinoembryonic antigen (CEA) may be involved in both cell-cell and cell-substrate adhesion. Our purpose was to determine whether epitopes involved in the homophilic binding of human colorectal carcinoma cells to CEA participated in adhesion to basement membrane proteins. Three human colorectal adenocarcinoma cell lines and one CHO cell line transfected with CEA cDNA were tested in a solid-phase adhesion assay. The 2 CEA-expressing carcinoma cell lines (KM-12c and CCL 188) and the transfectant, but not the parental CHO line, bound to CEA. The CEA-non-producing carcinoma line (Clone A) did not bind to CEA. All colorectal carcinoma cell lines, the transfectant and the parental CHO line bound to laminin, while the colorectal carcinoma lines bound to type-IV collagen. MAbs to epitopes on CEA that cross-react with non-specific cross-reacting antigen (NCA) inhibited adhesion of CEA-expressing cells to CEA. MAbs to non-cross-reactive epitopes of CEA did not block adhesion to CEA. When the inhibitory anti-CEA antibodies were compared in a competitive radioimmunoassay, 2 distinct epitopes were identified. Epitope I is in the N-terminal domain and defined by MAbs MN3, T84.1 and C110, whereas epitope II is located in the repeating loop domains and is recognized by antibodies MN15, PR3B10 and NP1. None of the antibodies to epitope I or II blocked adhesion by KM-12c or CCL 188 cells to laminin or type-IV collagen. Thus, at least 2 different regions on CEA participate in adhesion to CEA but not to collagen or laminin by CEA-expressing human colorectal carcinoma cells.

Carcinoembryonic antigen (CEA) is an oncofetal antigen whose function in the progression of colorectal carcinoma remains unclear although recent studies suggest it participates in homotypic cellular adhesion. We have previously shown that 40 micrograms of CEA injected intravenously into athymic nude mice enhances experimental metastasis in liver and lung by two human colorectal carcinoma cell lines that are injected intrasplenically 30 min later. The metastatic potential of another three moderately to highly metastatic colorectal carcinoma cell lines and of one weakly metastatic line has now been analysed in this model. CEA pretreatment only enhanced colony formation by cell lines that were weakly metastatic in untreated nude mice; it did not affect experimental metastasis by highly metastatic lines. CEA pretreatment enhanced the retention of 125I Idudr-labelled weakly metastatic tumour cells within the liver and lungs 4 h after intrasplenic injection but not the retention of highly metastatic tumour cells or inert latex beads. A significant correlation existed between the formation of experimental metastases and the early retention of tumour cells within the liver after intrasplenic injection. Aggregation did not appear to be important for retention in liver because CEA did not aggregate colorectal carcinoma cells in vitro. Also CEA did not alter natural host effector cell function in a cytolysis assay in vitro. We suggest that CEA facilitates liver colonisation by three of eight human colorectal carcinomas in athymic nude mice by increasing the hepatic retention of tumour cells. The potential mechanisms by which CEA may increase the retention of tumour cells in the liver are discussed.

We tested whether nuclear imaging with indium111 (111In)-labeled murine monoclonal (MoAb) anticarcinoembryonic antigen (anti-CEA) ZCE-025 antibody could detect recurrent disease in patients with a rising serum CEA level but negative findings for computed tomographic (CT) scans of the abdomen and pelvis, chest radiograph, and colonoscopy or barium enema. Twenty patients with a history of completely resected CEA-producing adenocarcinoma (18 with colon cancer, one with breast cancer, and one with Hodgkin's disease) and a rising serum CEA level were given an intravenous infusion of 2 mg of 111In-labeled ZCE-025 mixed with 38 mg of unlabeled ZCE-025. Planar and single-photon emission CT (SPECT) scans were acquired at 72 and 144 hours, and in 19 of the 20 patients these were positive. Of those 19, 13 underwent exploratory surgery, and cancer was found in 10, and two had a diagnostic biopsy, which confirmed cancer. Three patients who had negative laparotomies and all four patients who did not undergo surgery or biopsy were followed radiologically. In all seven, cancer was subsequently detected at the sites suggested by the ZCE-025 scan. Thus, tumor was confirmed in all 19 patients with positive scans. Five of 13 patients who were explored benefited from the study and the exploratory laparotomy, as disease was entirely resected in four or was subjected to definitive radiation therapy to the pelvis in the fifth. In two additional patients who were not explored, MoAb imaging resulted in definitive therapy to regionally confined recurrent disease. 111In-labeled anti-CEA MoAb ZCE-025 scanning in patients with rising CEA successfully imaged metastatic colorectal cancer that eluded detection by other methods and affected the care given to some. These results suggest an important role for 111In-labeled ZCE-025 scanning among patients with rising CEA and otherwise occult metastatic cancer.

Although the serum level of carcinoembryonic antigen (CEA) is directly associated with a poor prognosis in human colorectal carcinoma (CRC), its function is obscure. As a member of the immunoglobulin supergene family, CEA may be involved with intercellular recognition and binding and facilitate attachment of CRC to sites of metastasis. In an experimental metastasis model of CRC in athymic nude mice, a systemic injection of CEA enhanced experimental liver metastasis and implantation in liver by a weakly metastatic CRC. This CRC also selectively bound to CEA that was attached to plastic. Thus, CEA may function as an attachment factor for CRC.

Patients with human colorectal carcinoma have a poor prognosis when serum carcinoembryonic antigen level exceeds 5 ng/mL. The hypothesis that carcinoembryonic antigen enhances metastasis by promoting the attachment of tumor cells to Kupffer cells and hepatocytes was tested in an experimental metastasis model in which colorectal carcinoma cells were injected into the spleens of BALB/c athymic nude mice and liver colonies counted 5 weeks later. Pretreatment with systemic injections of carcinoembryonic antigen significantly increased the metastatic potential of a poorly metastatic colorectal carcinoma cell line KM-12c, but did not induce the nonmetastatic colorectal carcinoma cell line HC 2998 to produce metastases, nor did carcinoembryonic antigen make the highly metastatic colorectal carcinoma cell line mHC 1410 more metastatic. Carcinoembryonic antigen did not stimulate proliferation of colorectal carcinoma but appeared to be a cofactor for metastasis possibly as an adhesion factor.

Carcinoembryonic antigen (CEA) is a glycoprotein that has been useful as a tumor marker to predict recurrence in gastrointestinal malignancies, but whose biological function has not been elucidated. With the recent evidence that CEA is a member of the immunoglobulin supergene family, CEA may be involved in intercellular recognition and binding. This review examines the role that CEA plays in the development of metastases by colorectal carcinoma.

A preoperative serum carcinoembryonic antigen (CEA) concentration greater than 5 ng/ml portends a poor prognosis for patients with colorectal carcinoma. The purpose of this study was to determine if the tumorigenicity of colorectal carcinomas in nude mice was associated with the preoperative serum CEA concentration. Neoplasms from 53 patients were either implanted as fragments or dissociated with collagenase and DNase, and 3 x 10(6) viable cells were injected into the flanks of BALB/c nude mice. The growth potential of tumors resected from patients with CEA levels exceeding 5 ng/ml was greater than that of tumors from patients with normal serum CEA: 26 of 33 carcinomas from patients with CEA greater than or equal to 5 ng/ml were tumorigenic in nude mice, whereas only 8 of 22 neoplasms from patients with normal serum CEA were tumorigenic in nude mice (P less than 0.001). Primary colorectal cancers, not metastases, were the basis for the association between tumorigenicity and preoperative CEA. Tumorigenicity was also associated with stage of disease, since Dukes' D primary tumors and metastases were more tumorigenic than Dukes' A to C primary tumors. Growth in nude mice was not associated with other prognostic factors such as tumor site, mucin production, local invasion, or stage of histological differentiation. The tumorigenic capability of human colorectal carcinomas may be associated with the preoperative serum CEA concentration and may reflect an increased potential to develop clinical metastases.

Recent interest has focused on fucosylated epitopes expressed on human neoplasms. The plant lectin Ulex europus agglutinin, Type I (UEA) binds fucosylated oligosaccharides, while UEA-reactive substances have a tissue distribution similar to carcinoembryonic antigen (CEA). We sought to determine if UEA reacted with CEA in extracts of fresh primary and metastatic colorectal carcinomas and paired normal tissues. The extracts were electrophoretically transferred to nitrocellulose membranes after the proteins were separated by SDS-PAGE in 10% polyacrylamide gels. The transfer membranes were then stained with peroxidase-conjugated UEA (UEA-P) or antibody to CEA (CEA-P). UEA-P reacted with a 170-190-kDa band in extracts of 22 of 30 primary tumors, 10 of 12 metastases, but only 1 of 5 villous adenomas. UEA-P generally did not react with normal colon or liver extracts. UEA-P also did not bind to 170-190-kDa molecules in Western transfers of a breast carcinoma metastatic to bowel and a focal nodular hyperplasia of liver. CEA-P displayed similar reactivity and detected CEA in a tumor extract negative for UEA. Fucose blocked binding of UEA-P to Western transfers of tumor extracts. CEA-P reacted with a 170-190-kDa substance in tumor extracts eluted with fucose from a column of immobilized UEA. Thus, UEA reacts with fucosylated oligosaccharides on most, but not all, species of CEA and may be a useful adjunct to anti-CEA immunohistochemistry.

BACKGROUND The Collaborative Stage (CS) Data Collection System enables multiple cancer registration programs to document anatomic and molecular pathology features that contribute to the Tumor (T), Node (N), Metastasis (M) - TNM - system of the American Joint Committee on Cancer (AJCC). This article highlights changes in CS for colon and rectal carcinomas as TNM moved from the AJCC 6th to the 7th editions. METHODS Data from 18 Surveillance, Epidemiology, and End Results (SEER) population-based registries were analyzed for the years 2004-2010, which included 191,361colon and 73,341 rectal carcinomas. RESULTS Overall, the incidence of colon and rectal cancers declined, with the greatest decrease in stage 0. The AJCC's 7th edition introduction of changes in the subcategorization of T4, N1, and N2 caused shifting within stage groups in 25,577 colon and 10,150 rectal cancers diagnosed in 2010. Several site-specific factors (SSFs) introduced in the 7th edition had interesting findings: 1) approximately 10% of colon and rectal cancers had tumor deposits - about 30%-40% occurred without lymph node metastases, which resulted in 2.5% of colon and 3.3% of rectal cases becoming N1c (stage III A/B) in the AJCC 7th edition; 2) 10% of colon and 12% of rectal cases had circumferential radial margins <1 mm; 3) about 46% of colorectal cases did not have a carcinoembryonic antigen (CEA) testing or documented CEA information; and 4) about 10% of colorectal cases had perineural invasion. CONCLUSIONS Adoption of the AJCC 7th edition by the SEER program provides an assessment tool for staging and SSFs on clinical outcomes. This evidence can be used for education and improved treatment for colorectal carcinomas. Cancer 2014;120(23 suppl):3793-806. © 2014 American Cancer Society. [ABSTRACT FROM AUTHOR]