Inhibition of prostate tumor angiogenesis by the tumor suppressor CEACAM1

Evaluation of the preventive and therapeutic effects of a recombinant vector co-expressing prostate-specific stem cell antigen and Clostridium perfringens enterotoxin on prostate cancer in rats

The effects of Clostridium perfringens enterotoxin (CPE) and prostate stem cell antigen (PSCA) on cancer prevention or treatment have been previously studied separately. For the first time, here we have elaborated a recombinant vector to co-express and study the cumulative effects of both of these factors on prostate cancer (PCa) in an animal model. The recombinant pBudCE4.1-cpe-PSCA vector was constructed in large scale. Rats were vaccinated by vector or vector plus chitosan nanoparticles before or after induction of PCa (preventive or therapeutic studies) by N-methyl N-nitrosurea and testosterone. Prostate tumors were weighed and histologically examined. Tumors and infusion site tissues as well as blood samples of all rats were collected and assessed by serological and molecular tests. We showed that vaccination with vector (along with or without nanoparticles) led to lower PCa incidence and tumor weight. The L-1β, IL6, and TNF-α serum levels and their gene expression accompanied by C-CAM1 gene expression in vaccinated groups were significantly higher than controls while no difference was seen in CK20 expression among all groups. Our findings showed that vector could effectively stimulate the immune system of rats to either prevent or suppress the PCa tumors. Adding chitosan nanoparticles did not affect the results significantly.

Tumor intrinsic immunity related proteins may be novel tumor suppressors in some types of cancer

Immune checkpoint blockade therapy (ICBT) can unleash T-cell responses against cancer. However, only a small fraction of patients exhibited responses to ICBT. The role of immune checkpoints in cancer cells is not well understood. In this study, we analyzed T-cell coinhibitory/costimulatory genes across more than 1100 samples of the Cancer Cell Line Encyclopedia (CCLE). Nearly 90% of such genes were not expressed or had low expression across the CCLE cancer cell lines. Cell line screening showed the enrichment of cancer cells deprived of the expression of CD27, CEACAM1, CTLA4, LRIG1, PDCD1LG2, or TNFRSF18, suggesting their role as tumor suppressor. The metagene expression signature derived from these six genes - Immu6Metagene was associated with prolonged survival phenotypes. A common set of five oncogenic pathways were significantly inhibited in different types of tumors of the cancer patients with good survival outcome and high Immu6Metagene signature expression. These pathways were TGF-β signaling, angiogenesis, EMT, hypoxia and mitotic process. Our study showed that oncoimmunology related molecules especially the six genes of the Immu6Metagene signature may play the tumor suppressor role in certain cancers. Therefore, the ICBT targeting them should be considered in such context to improve the efficacy.

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.

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.

A comprehensive phylogenetic and structural analysis of the carcinoembryonic antigen (CEA) gene family

The carcinoembryonic antigen (CEA) gene family belongs to the immunoglobulin (Ig) superfamily and codes for a vast number of glycoproteins that differ greatly both in amino acid composition and function. The CEA family is divided into two groups, the carcinoembryonic antigen-related cell adhesion molecules (CEACAMs) and the pregnancy-specific glycoproteins. The CEA family members are implicated in pleiotropic (patho)physiological functions including cell-cell adhesion, pregnancy, immunity, neovascularization, regulation of insulin homeostasis, and carcinogenesis. In general, the CEA-encoded proteins are composed of an extracellular region with Ig variable and constant-like domains and a cytoplasmic region containing signaling motifs. Of particular interest, the well-studied human and mouse CEA genes are arranged in clusters in a single chromosome. Taking into account this characteristic, we made an effort to reconstruct the evolutionary history of the CEA gene family. Toward this end, the publicly available genomes were searched extensively for CEA homologs. The domain organization of the retrieved protein sequences was analyzed, and, subsequently, comprehensive phylogenetic analyses of the entire length CEA homologous proteins were performed. A series of evolutionarily conserved amino acid residues, functionally important, were identified. The relative positioning of these residues on the modeled tertiary structure of novel CEA protein domains revealed that they are, also, spatially conserved. Furthermore, the chromosomal arrangement of CEA genes was examined, and it was found that the CEA genes are preserved in terms of position, transcriptional orientation, and number in all species under investigation.

Carcinoembryonic antigen-related cell adhesion molecule 1 negatively regulates granulocyte colony-stimulating factor production by breast tumor-associated macrophages that mediate tumor angiogenesis

Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1), a cell adhesion molecule expressed on epithelial cells and activated immune cells, is downregulated in many cancers and plays a role in inhibition of inflammation in part by inhibition of granulocyte colony-stimulating factor (G-CSF) production by myeloid cells. As macrophages are associated with a poor prognosis in breast cancer, but play important roles in normal breast, we hypothesized that CEACAM1 downregulation would lead to tumor promotion under inflammatory conditions. Cocultures of proinflammatory M1 macrophages with CEACAM1 negative MCF7 breast cells produced high levels of G-CSF (10 ng/mL) compared to CEACAM1-transfected MCF7/4S cells (1 ng/mL) or anti-inflammatory M2 macrophage cocultures (0.5 or 0.1 ng/mL, MCF7 or MCF7/4S, respectively). The expression of CEACAM1 on M1s was much greater than for M2s and was observed only in cocultures with either MCF7 or MCF7/4S cells. When M1 macrophages were mixed with MCF7 cells and implanted in murine mammary fat pads of nonobese diabetic/severe combined immunodeficient mice, tumor size and blood vessel density were significantly greater than MCF7 or MCF7/4S only tumors which were hardly detected after 8 weeks of growth. In contrast, M1 cells had a much reduced effect on MCF7/4S tumor growth and blood vessel density, indicating that the tumor inhibitory effect of CEACAM1 is most likely related to its anti-inflammatory action on inflammatory macrophages. These results support our previous finding that CEACAM1 inhibits both G-CSF production by myeloid cells and G-CSF-stimulated tumor angiogenesis.

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.

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

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

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

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

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

CEACAM1: a novel urinary marker for bladder cancer detection

BACKGROUND

Carcinoembryonic antigen-related cell adhesion molecule 1 (biliary glycoprotein; CEACAM1) is expressed in normal bladder urothelium and in angiogenically activated endothelial cells, where it exhibits proangiogenic properties.

OBJECTIVE

The aim of this study was to evaluate the value of urinary CEACAM1 for detection of urothelial carcinoma of the bladder (UCB).

DESIGN, SETTING, AND PARTICIPANTS

This prospective study included 175 patients.

MEASUREMENTS

Immunohistochemistry for CEACAM1 was performed on UCB sections of 10 patients. Enzyme-linked immunosorbent assay (ELISA) for CEACAM1 was performed on urine specimens of healthy volunteers (n=30), patients with benign prostatic hyperplasia (BPH; n=5), severe cystitis (n=5), non-muscle-invasive UCB (n=72), muscle-invasive UCB (n=21), or past history of UCB without evidence of disease (n=42). Western blot analysis was performed on a subgroup of these subjects (n=53).

RESULTS AND LIMITATIONS

CEACAM1 immunostaining in normal urothelium disappears in noninvasive UCB but appears in endothelial cells of adjacent vessels. Western blotting revealed presence of CEACAM1 in the urine of no healthy volunteers, of 76% of noninvasive UCB patients, and of 100% of invasive UCB patients. ELISA analysis confirmed that urinary CEACAM1 levels were significantly higher in UCB patients compared with control subjects (median: 207 ng/ml vs 0 ng/ml; p<0.001). The area under the curve for UCB detection was 0.870 (95% confidence interval [CI]: 0.810-0.931). In multivariable logistic regression analyses that adjusted for the effects of age and gender, higher CEACAM1 levels were associated with cancer presence (hazard ratio [HR]: 2.89; 95% CI: 2.01-4.15; p<0.001) and muscle-invasive cancer (HR: 5.53; 95% CI: 1.68-18.24; p=0.005). The cut-off level of 110 ng/ml yielded sensitivity of 74% and specificity of 95% for detecting UCB. Sensitivity was 88% for detecting high-grade UCB and 100% for detecting invasive-stage UCB. Larger studies are necessary to establish the diagnostic and prognostic roles of this highly promising novel marker in UCB.

CONCLUSIONS

Urinary CEACAM1 levels discriminate UCB patients from non-UCB subjects. Moreover, urinary levels of CEACAM1 increased with advancing stage and grade.

CEACAM1 distribution and it's effects on angiogenesis and lymphangiogenesis in oral carcinoma

To investigate the expression of carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) and its effects on angiogenesis and lymphangiogenesis in oral carcinoma. Immunohistochemistry was used to study the expression of CEACAM1, LYVE1 and CD31, double-labelling immunofluorescence was used to detect the co-expression of CEACAM1 and LYVE1, and double-labelling immunohistochemistry was performed to observe the co-expression of LYVE1 and CD31 in vessels. Membranous CEACAM1 was expressed in well-differentiated squamous cell carcinoma and cytoplastic CEACAM1 in poorly and moderately differentiated carcinoma (P<0.05). More CEACAM1-positive vessels were observed in CEACAM1-positive tumors with cytoplasmic expression than with membranous expression (P<0.001). Co-expression of CEACAM1 and LYVE1, LYVE1 and CD31 in vessels was more common in CEACAM1-positive tumors with cytoplasmic expression than with membranous expression (P<0.001). CEACAM1 has different distribution in oral carcinoma. Membranous CEACAM1 inhibits angiogenesis and lymphangiogenesis, but cytoplasmic CEACAM1 promotes angiogenesis, and even promotes lymphangiogenesis by mediating the transformation of vascular endothelial cells (VECs) into lymphatic endothelial cells (LECs).

Dynamic expression of protective CEACAM1 on melanoma cells during specific immune attack

An efficient immune response against tumours depends on a well-orchestrated function of integrated components, but is finally exerted by effector tumour-infiltrating lymphocytes (TIL). We have previously reported that homophilic CEACAM1 interactions inhibit the specific killing and interferon-gamma (IFN-gamma) release activities of natural killer cells and TIL. In this study a model for the investigation of melanoma cells surviving long coincubation with antigen-specific TIL is reported. It is demonstrated that the surviving melanoma cells increase their surface CEACAM1 expression, which in turn confers enhanced resistance against fresh TIL. Furthermore, it is shown that this is an active process, driven by specific immune recognition and is at least partially mediated by lymphocyte-derived IFN-gamma. Similar results were observed with antigen-restricted TIL, either autologous or allogeneic, as well as with natural killer cells. The enhanced CEACAM1 expression depends, however, on the presence of IFN-gamma and sharply drops within 48 hr. This may be a mechanism that allows tumour cells to transiently develop a more resistant phenotype upon recognition by specific lymphocytes. Therefore, this work substantiates the melanoma-promoting role of CEACAM1 and marks it as an attractive target for novel immunotherapeutic interventions.

CEACAM1/VEGF cross‐talk during neuroblastic tumour differentiation

The role of angiogenesis in tumour progression is a major subject in modern oncology and a correlation between angiogenesis and poor outcome has been demonstrated for human neuroblastomas. However, the role of angiogenesis in the maturation phase of neuroblastic tumours has never been considered. Human carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1), a potent pro-angiogenic factor and mediator of vascular endothelial growth factor (VEGF)-induced angiogenesis, plays a crucial role during the activation phase of angiogenesis and it has been shown to be expressed in the microvessels of the developing central nervous system as well as in newly formed immature blood vessels in many different tumours and under physiological conditions. The present study has investigated the role of CEACAM1/VEGF-mediated angiogenesis across the whole spectrum of neuroblastic tumours, from undifferentiated to fully differentiated mature ganglioneuromas. CEACAM1 is peculiarly expressed in the microvessels of areas of active tumour maturation among differentiating neuroblastic/ganglion cells, whereas it is completely absent in the vessels of poorly differentiated/undifferentiated as well as in entirely mature Schwannian-rich areas. Interestingly, VEGF expression has been found in differentiating neuroblastic/ganglion cells adjacent to CEACAM1-positive microvessels. In keeping with these observations, VEGF expression was found in human neuroblastoma SH-SY5Y cells during differentiation after retinoic acid treatment. Moreover, conditioned medium from SH-SY5Y cells collected at different stages of differentiation induced progressive in vitro up-regulation of CEACAM1 expression in human umbilical vein endothelial cells (HUVECs) that was abrogated by the specific VEGF receptor-2/KDR inhibitor SU5416. Taken together, these data point to a role for CEACAM1/VEGF cross-talk during the maturation phase of neuroblastic tumours. This may mimic physiological events leading to maturation of the vasculature in the developing normal central nervous system. On the other hand, in poorly differentiated/undifferentiated lesions, VEGF-sustained angiogenesis does not reproduce physiological steps, but rather is associated with tumour aggressiveness and may involve other molecular pathways.

Inhibition of human tumor-infiltrating lymphocyte effector functions by the homophilic carcinoembryonic cell adhesion molecule 1 interactions

Efficient antitumor immune response requires the coordinated function of integrated immune components, but is finally exerted by the differentiated effector tumor-infiltrating lymphocytes (TIL). TIL cells comprise, therefore, an exciting platform for adoptive cell transfer (ACT) in cancer. In this study, we show that the inhibitory carcinoembryonic Ag cell adhesion molecule 1 (CEACAM1) protein is found on virtually all human TIL cells following preparation protocols of ACT treatment for melanoma. We further demonstrate that the CEACAM1 homophilic interactions inhibit the TIL effector functions, such as specific killing and IFN-gamma release. These results suggest that CEACAM1 may impair in vivo the antitumor response of the differentiated TIL. Importantly, CEACAM1 is commonly expressed by melanoma and its presence is associated with poor prognosis. Remarkably, the prolonged coincubation of reactive TIL cells with their melanoma targets results in increased functional CEACAM1 expression by the surviving tumor cells. This mechanism might be used by melanoma cells in vivo to evade ongoing destruction by tumor-reactive lymphocytes. Finally, CEACAM1-mediated inhibition may hinder in many cases the efficacy of TIL ACT treatment of melanoma. We show that the intensity of CEACAM1 expression on TIL cells constantly increases during ex vivo expansion. The implications of CEACAM1-mediated inhibition of TIL cells on the optimization of current ACT protocols and on the development of future immunotherapeutic modalities are discussed.

Gene expression profiling in R-flurbiprofen-treated prostate cancer: R-Flurbiprofen regulates prostate stem cell antigen through activation of AKT kinase

We have used gene expression profiling to characterize genes regulated by the anti-tumor non-steroidal anti-inflammatory drug (NSAID)-like agent R-flurbiprofen (RFB) in murine TRAMP prostate cancer. Mice with spontaneous, palpable tumors were treated with RFB 25 mg/(kgd) x 7d orally, or vehicle only. RNA was then extracted from tumor tissue and used for microarray analysis with Affymetrix chips. Fifty-eight genes were reproducibly regulated by RFB treatment. One of the most highly up-regulated genes was prostate stem cell antigen (psca). We used TRAMP C1 murine prostate cancer cells to examine potential mechanisms through which RFB could regulate psca. RFB induced dose-dependent expression of PSCA protein, and activity of the psca promoter, in TRAMP C1 cells in culture. Increased psca promoter activity was also seen following treatment of cells with sulindac sulfone, another NSAID-like agent, but not with celecoxib treatment. RFB activation of the psca promoter could be attenuated by co-transfection of dominant-negative akt and h-ras constructs, but not by dominant-negative mek1 plasmids. Immunoblotting revealed that RFB increased expression of phosphorylated AKT at concentrations that stimulated psca promoter activity, and that increased PSCA protein expression. In addition, RFB-dependent up-regulation of PSCA protein expression could be blocked by AKT inhibitors. These data demonstrate that RFB, and possibly other NSAID-like analogs, can increase expression of the psca gene both in vivo and in culture. They further suggest the utility of combining RFB with AKT inhibitors or with monoclonal antibodies targeting PSCA protein, for treatment or prevention of prostate cancer.

Deletion of the carcinoembryonic antigen-related cell adhesion molecule 1 (Ceacam1) gene contributes to colon tumor progression in a murine model of carcinogenesis

Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) is a glycoprotein that is part of the carcinoembryonic antigen and the immunoglobulin superfamilies. We have shown that it functions as a tumor suppressor and that this function depends upon the presence of the longer CEACAM1 cytoplasmic domain. In this report, we describe the generation of a Ceacam1-/- mouse. The Ceacam1-/- colon exhibits increased in vivo proliferation relative to the wild-type counterpart with a corresponding decreased expression of the p21(Cip1) and p27(Kip1) Cyclin D kinase inhibitors. The colonic villi undergo decreased apoptosis. Out of 35 litters of mice, no spontaneous tumors in any tissues normally expressing CEACAM1 were found over the lifespan of the animals, suggesting that CEACAM1 may not be involved in initiation of tumor development. However, when mice are treated with azoxymethane to induce colonic tumors, we find that Ceacam1-/- mice developed a significantly greater number of tumors than their littermate controls. Moreover, the tumor size was greater in the knockout mice relative to that in the wild-type mice. These results indicate that deletion of CEACAM1 favors progression of colon tumorigenesis.

CEA-related cell adhesion molecule-1 is involved in angiogenic switch in prostate cancer

We demonstrate here that epithelial carcinoembryonic antigen (CEA)-related cell adhesion molecule-1 (CEACAM1) downregulation in prostate intraepithelial neoplasia (PIN) is inversely correlated with its upregulation in adjacent blood vessels. CEACAM1 silencing in prostate cancer cell line DU-145 via small interfering ribonucleic acid (siRNA) increased but its overexpression suppressed the expression of angiogenic/lymphangiogenic factors such as vascular endothelial growth factor (VEGF)-A, -C and -D, and angiogenic inhibitor collagen 18/endostatin. Furthermore, CEACAM1 overexpression in DU-145 cells increased but CEACAM1 silencing reduced angiopoietin-1 expression. Inverse relation was found for angiopoietin-2. Supernatant of CEACAM1-overexpressing DU-145 suppressed but that of CEACAM1-silenced increased the VEGF-induced endothelial tubes. Electron microscopically the majority of PIN-associated blood vessels was structurally destabilized exhibiting endothelial fenestration, trans- and inter-endothelial gaps. In some PIN areas, invasion of single tumor cells into the destabilized blood vessels was observed. These data show that disappearance of epithelial CEACAM1 in PIN is accompanied by its upregulation in adjacent vasculature which apparently correlates with vascular destabilization and increased vascularization of prostate cancer. Strategies to either conserve the epithelial CEACAM1 or to target endothelial CEACAM1 might be useful for an anti-angiogenic therapy of prostate cancer.

Selection, affinity maturation, and characterization of a human scFv antibody against CEA protein

BACKGROUND

CEA is a tumor-associated antigen abundantly expressed on several cancer types, including those naturally refractory to chemotherapy. The selection and characterization of human anti-CEA single-chain antibody fragments (scFv) is a first step toward the construction of new anticancer monoclonal antibodies designed for optimal blood clearance and tumor penetration.

METHODS

The human MA39 scFv, selected for its ability to recognize a CEA epitope expressed on human colon carcinomas, was first isolated from a large semi-synthetic ETH-2 antibody phage library, panned on human purified CEA protein. Subsequently, by in vitro mutagenesis of a gene encoding for the scFv MA39, a new library was established, and new scFv antibodies with improved affinity towards the CEA cognate epitope were selected and characterized.

RESULTS

The scFv MA39 antibody was affinity-maturated by in vitro mutagenesis and the new scFv clone, E8, was isolated, typed for CEA family member recognition and its CEACAM1, 3 and 5 shared epitope characterized for expression in a large panel of human normal and tumor tissues and cells.

CONCLUSION

The binding affinity of the scFv E8 is in a range for efficient, in vivo, antigen capture in tumor cells expressing a shared epitope of the CEACAM1, 3 and 5 proteins. This new immunoreagent meets all criteria for a potential anticancer compound: it is human, hence poorly or not at all immunogenic, and it binds selectively and with good affinity to the CEA epitope expressed by metastatic melanoma and colon and lung carcinomas. Furthermore, its small molecular size should provide for efficient tissue penetration, yet give rapid plasma clearance.

Novel biomarkers in malignant melanoma

Cutaneous malignant melanoma remains the leading cause of skin cancer death in industrialized countries. Melanoma progression is well defined in its clinical and histopathological aspects (Breslow's index, tumour size, ulceration, or vascular invasion), which also give hints to prognosis of the patient. Use of molecular markers should therefore give additional information which cannot be determined by routine histopathology. Markers showing only a correlation to Clark level or tumour size are not useful. Several molecules influencing invasiveness and metastatic dissemination of melanoma have been identified. Expression of these molecules has been studied in primary melanoma and correlated with prognosis. Moreover, several tumour suppressors and oncogenes have been shown to be involved in melanoma pathogenesis, including CDKN2A, PTEN, TP53, RAS and MYC, but have not been related to melanoma subtypes or validated as prognostic markers. In the past, in melanoma, an increase in the number of positive tumour cells for Ki67 (detected by Mib1), cyclin A, cyclin D, MMP-2, integrins beta1 and beta3 or osteonectin were considered as factors of poor prognosis as well as the decrease in p16, p27, and Melan A. However, only a small subset of these proteins has a prognostic value independent of tumour thickness. The recent development of high-throughput technologies analyzing global molecular profiles of cancer is bringing up previously unknown candidate genes involved in melanoma, such as Wnt-5A and B-raf. Here, recently published data related to new genes involved in melanoma pathogenesis, which may represent important biomarkers for the identification of genetic profiles or indication of progression of melanoma, are reviewed.

Stimulation of CEACAM1 expression by 12- O -tetradecanoylphorbol-13-acetate (TPA) and calcium ionophore A23187 in endometrial carcinoma cells

Downregulation of carcinoembryonic antigen-related cell adhesion molecule (CEACAM1), a cell adhesion molecule with tumor suppressing properties has been observed in a high percentage of carcinomas of the endometrium and other malignancies. The mechanisms for the dysregulation and the role of hormones and cytokines on the expression of CEACAM1 in endometrial carcinomas is unknown. We therefore studied the effect of estradiol, medroxyprogesterone acetate (MPA), RU486, gamma-interferon (IFN-gamma), tumor necrosis factor alpha (TNF-alpha), 12-O-tetradecanoylphorbol-13-acetate (TPA) and calcium ionophore A23187 on the expression in the non-expressing endometrial tumor cell lines Hec1B and Skut1B, respectively. No induction of CEACAM1 expression was observed in Hec1B endometrial adenocarcinoma cells in response to hormones and cytokines whereas treatment with TPA and calcium ionophore A23187 resulted in the strong expression of endogenous CEACAM1 on the mRNA and protein levels. In contrast, no induction of CEACAM1 expression was observed in endometrial mixed mesenchymal Skut1B cells. Studies of other members of the CEACAM family revealed that the re-expression in Hec1B carcinoma cells is restricted to CEACAM1 suggesting a cell type-specific and cell type-independent mechanism of CEACAM1 activation via the protein kinase C (PKC) pathway. Induction of CEACAM1 expression was dependent on protein kinase C protein synthesis and luciferase reporter assays with CEACAM1 promoter constructs demonstrated that the re-expression of CEACAM1 is regulated at the transcriptional level. This is the first report demonstrating that activators of PKC are able to specifically induce the expression of CEACAM1 in human carcinoma cells and our findings may provide a basis for the therapeutic inhibition of tumor growth in malignancies in which CEACAM1 is downregulated.

Carcinoembryonic Antigen–Related Cell Adhesion Molecule 1a-4L Suppression of Rat Hepatocellular Carcinomas

Carcinoembryonic antigen (CEA)–related cell adhesion molecule 1 (CEACAM1) is a member of the CEA family of immunoglobulin-like adhesion molecules with two major splice variants, CEACAM1a-4L and CEACAM1b-4S, differing in the length of their COOH-terminal cytoplasmic tail. Both forms are down-regulated in prostate and liver carcinomas relative to normal tissues. We have previously shown in a nude mouse xenograft model that restoration of CEACAM1a-4L expression in human prostate carcinoma cells (PC-3) suppresses tumorigenicity, an effect observed with carcinomas from several other tissues but never established for hepatocellular carcinomas. In this report, we have examined the effect of CEACAM1a-4L on tumorigenicity of 1682A, a rat hepatocellular carcinoma that grows on the omentum when injected into the peritoneal cavity. Results show that restoration of CEACAM1a-4L expression at levels 13- and 0.45-fold compared with negative controls or normal hepatocytes, respectively, completely suppressed the formation of 1682A tumor nodules on the omentum at 3 weeks after injection. In contrast, 1682A cells infected with CEACAM1b-4S or an empty retroviral vector formed multiple clusters of tumor nodules. Although tumor nodules of 1682A cells positive and negative for CEACAM1a-4L did not display significant differences in histologic organization, aggregates formed in vitro by 1682A-L were smaller in size and displayed enlarged intercellular spaces relative to their 1682A-V counterparts. Restoration of CEACAM1a-4L expression did not elevate levels of apoptosis but seemed to cause an increase in the length of G1. This is the first demonstration of CEACAM1a-4L–induced tumor suppression in liver carcinomas using a quantifiable i.p. syngeneic transplantation model.

Loss of carcinoembryonic antigen-related cell adhesion molecule 1 expression is an adverse prognostic factor in hepatocellular carcinoma

BACKGROUND

Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) is a negative regulator of tumor cell growth, and may function as a tumor suppressor. CEACAM1 expression is down-regulated with increasing histologic grade in a number of malignancies. The authors hypothesized that loss of CEACAM1 expression in hepatocellular carcinoma (HCC) cells may function as an adverse prognostic factor.

METHODS

A retrospective analysis was conducted of 139 consecutive patients who underwent resection for HCC, with a median follow-up period of 83 months. Immunohistochemistry of the resected specimens was conducted using a monoclonal anti-CEACAM1 antibody. CEACAM1 expression in HCC was classified into two categories: diffuse expression, characterized by positive staining throughout the tumor specimen, or loss of expression, in which there were distinct areas of negative staining within the tumor specimen.

RESULTS

Of the 139 patients, 113 were classified as having tumors with diffuse expression and 26 had loss-of-expression tumors. Loss of CEACAM1 expression was more frequent in tumor specimens with Edmondson-Steiner Grades III or IV (21 of 32 [66%]) than in tumor specimens with Grades I or II (5 of 107 [5%]; P < 0.001) and was always seen in areas with the highest histologic grade. Loss of CEACAM1 expression was significantly associated with large tumor size, multiplicity of the tumor, portal vein invasion, and satellite nodules and affected survival adversely, according to univariate (P < 0.0001) and multivariate analyses (relative risk, 5.737; P < 0.001).

CONCLUSIONS

Loss of CEACAM1 expression reflects aggressive tumor biology and thus indicates a poor prognosis for patients with HCC.

Dual role of carcinoembryonic antigen-related cell adhesion molecule 1 in angiogenesis and invasion of human urinary bladder cancer

Here, we show that carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) is expressed in umbrella cells of bladder urothelium but is down-regulated in superficial bladder cancer, such as histologic tumor stage a (pTa) and transitional cell carcinoma in situ (pTis). Concurrently, CEACAM1 is up-regulated in the endothelia of adjacent angiogenic blood vessels. Mimicking the CEACAM1 down-regulation in the urothelium, CEACAM1 was silenced in bladder cancer cell lines 486p and RT4 using the small interfering RNA technique. CEACAM1 down-regulation was confirmed at the protein level by Western blot analyses. CEACAM1 silencing leads to a significant up-regulation of vascular endothelial growth factor (VEGF)-C and VEGF-D in quantitative reverse transcription-PCR. Correspondingly, supernatants from the CEACAM1-overexpressing bladder cancer cell lines reduce, but those from CEACAM1 silencing induce endothelial tube formation and potentiate the morphogenetic effects of VEGF. These data suggest that the epithelial down-regulation of CEACAM1 induces angiogenesis via increased expression of VEGF-C and VEGF-D. Inversely, CEACAM1 is up-regulated in endothelial cells of angiogenic blood vessels. This in turn is involved in the switch from noninvasive and nonvascularized to invasive and vascularized bladder cancer. CEACAM1 appears to be a promising endothelial target for bladder cancer therapy.

Pro-angiogenic signaling by the endothelial presence of CEACAM1

Here, we demonstrate the expression of carcinoembryonic antigen-related cell adhesion molecule-1 (CEACAM1) in angiogenic sprouts but not in large mother blood vessels within tumor tissue. Correspondingly, only human microvascular endothelial cells involved in in vitro tube formation exhibit CEACAM1. CEACAM1-overexpressing versus CEACAM1-silenced human microvascular endothelial cells were used in migration and tube formation assays. CEACAM1-overexpressing microvascular endothelial cells showed prolonged survival and increased tube formation when they were stimulated with vascular endothelial growth factor (VEGF), whereas CEACAM1 silencing via small interfering RNA blocks these effects. Gene array and LightCycler analyses show an up-regulation of angiogenic factors such as VEGF, VEGF receptor 2, angiopoietin-1, angiopoietin-2, tie-2, angiogenin, and interleukin-8 but a down-regulation of collagen XVIII/endostatin and Tie-1 in CEACAM1-overexpressing microvascular endothelial cells. Western blot analyses confirm these results for VEGF and endostatin at the protein level. These results suggest that constitutive expression of CEACAM1 in microvascular endothelial cells switches them to an angiogenic phenotype, whereas CEACAM1 silencing apparently abrogates the VEGF-induced morphogenetic effects during capillary formation. Thus, strategies targeting the endothelial up-regulation of CEACAM1 might be promising for antiangiogenic tumor therapy.

Cathepsin D Processes Human Prolactin into Multiple 16K-Like N-Terminal Fragments: Study of Their Antiangiogenic Properties and Physiological Relevance

16K prolactin (PRL) is the name given to the 16-kDa N-terminal fragment obtained by proteolysis of rat PRL by tissue extracts or cell lysates, in which cathepsin D was identified as the candidate protease. Based on its antiangiogenic activity, 16K PRL is potentially a physiological inhibitor of tumor growth. Full-length human PRL (hPRL) was reported to be resistant to cathepsin D, suggesting that antiangiogenic 16K PRL may be physiologically irrelevant in humans. In this study, we show that hPRL can be cleaved by cathepsin D or mammary cell extracts under the same conditions as described earlier for rat PRL, although with lower efficiency. In contrast to the rat hormone, hPRL proteolysis generates three 16K-like fragments, which were identified by N-terminal sequencing and mass spectrometry as corresponding to amino acids 1-132 (15 kDa), 1-147 (16.5 kDa), and 1-150 (17 kDa). Biochemical and mutagenetic studies showed that the species-specific digestion pattern is due to subtle differences in primary and tertiary structures of rat and human hormones. The antiangiogenic activity of N-terminal hPRL fragments was assessed by the inhibition of growth factor-induced thymidine uptake and MAPK activation in bovine umbilical endothelial cells. Finally, an N-terminal hPRL fragment comigrating with the proteolytic 17-kDa fragment was identified in human pituitary adenomas, suggesting that the physiological relevance of antiangiogenic N-terminal hPRL fragments needs to be reevaluated in humans.

Effects of resveratrol on gene expression in renal cell carcinoma

Studies have shown that Resveratrol (RE) can inhibit cancer initiation, promotion, and progression. However the gene expression profile in renal cell carcinoma (RCC) in response to RE treatment has never been reported. To understand the potential anticancer effect of RE on RCC at molecular level, we profiled and analyzed the expression of 2059 cancer-related genes in a RCC cell line RCC54 treated with RE. Biological functions of 633 genes were annotated based on biological process ontology and clustered into functional categories. Twenty-nine highly differentially expressed genes in RE treated RCC54 were identified and the potential implications of some gene expression alterations in RCC carcinogenesis were identified. RE was also shown to inhibit cell growth and induce cell death of RCC cells. The expression alterations of selected genes were validated using reverse transcription polymerase chain reaction. In addition, the gene expression profiles under different RE treatments were analyzed and visualized using singular value decomposition. The findings from this study support the hypothesis that RE induces differential expression of genes that are directly or indirectly related to the inhibition of RCC cell growth and induction of RCC cell death. In addition, it is apparent that the gene expression alterations due to RE treatment depend strongly on RE concentration. This study provides a general understanding of the overall genetic response of RCC54 to RE treatment and yields insights into the understanding of the cancer preventive mechanism of RE in RCC.

The Critical Role of Residues 43R and 44Q of Carcinoembryonic Antigen Cell Adhesion Molecules-1 in the Protection from Killing by Human NK Cells

The multifunctional carcinoembryonic Ag cell adhesion molecule (CEACAM)1 protein has recently become the focus of intense immunological research. We have previously shown that the CEACAM1 homophilic interactions inhibit the killing activity of NK cells. This novel inhibitory mechanism plays a key role in melanoma immune evasion, inhibition of decidual immune response, and controlling NK autoreactivity in TAP2-deficient patients. These roles are mediated mainly by homophilic interactions, which are mediated through the N-domain of the CEACAM1. The N-domain of the various members of the CEACAM family shares a high degree of similarity. However, it is still unclear which of the CEACAM family members is able to interact with CEACAM1 and what are the amino acid residues that control this interaction. In this study we demonstrate that CEACAM1 interacts with CEACAM5, but not with CEACAM6. Importantly, we provide the molecular basis for CEACAM1 recognition of various CEACAM family members. Sequence alignment reveals a dichotomy among the CEACAM family members: both CEACAM1 and CEACAM5 contain the R and Q residues in positions 43 and 44, respectively, whereas CEACAM3 and CEACAM6 contain the S and L residues, respectively. Mutational analysis revealed that both 43R and 44Q residues are necessary for CEACAM1 interactions. Implications for differential expression of CEACAM family members in tumors are discussed.

Identification of Sp2 as a transcriptional repressor of carcinoembryonic antigen-related cell adhesion molecule 1 in tumorigenesis

Down-regulation of carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) tumor suppressor gene expression is common in several malignancies including prostate, colon, and breast cancer. The mechanism that mediates this down-regulation is not known. Here, we report that down-regulation of CEACAM1 expression in prostate cancer cells occurs primarily at the transcriptional level and is mediated by Sp2, a member of the Sp family of transcription factors. Sp2 binds to the CEACAM1 promoter in vitro and in vivo, and transient overexpression of Sp2 down-regulates endogenous CEACAM1 expression in normal prostate epithelial cells. Sp2 appears to repress CEACAM1 gene expression by recruiting histone deacetylase activity to the CEACAM1 promoter. In human prostate cancer specimens, Sp2 expression is high in prostate cancer cells but low in normal prostate epithelial cells and is inversely correlated with CEACAM1 expression. Our studies show that transcriptional repression by Sp2 represents one mechanism by which CEACAM1 tumor suppressor gene is down-regulated in prostate cancer.

Multitasking in tumor progression: signaling functions of cell adhesion molecules

Approximately 90% of all cancer deaths arise from metastasis formation. Hence, understanding the molecular mechanisms underlying tumor progression, local invasion, and the formation of tumor metastases represents one of the great challenges in exploratory cancer research. Recent experimental results indicate that changes in cell adhesion play a critical role in tumor progression. Cell adhesion molecules of varying classes and functions, including cadherins, cell adhesion molecules of the immunoglobulin family (Ig-CAMs), CD44, and integrins, can interact with and modulate the signaling function of receptor tyrosine kinases (RTKs). Conversely, signaling by RTKs can directly affect the adhesive function of adhesion molecules. Loss of E-cadherin and gain of mesenchymal cadherin function as well as changes in the expression of Ig-CAMs during the progression of many cancer types exemplify such functional implicatons: cell adhesion molecules not only define a tumor cell's adhesive repertoire, but also directly influence classic signal transduction pathways, thereby modulating the metastatic behavior of tumor cells.

Human prostate cancer risk factors

Prostate cancer has the highest prevalence of any nonskin cancer in the human body, with similar likelihood of neoplastic foci found within the prostates of men around the world regardless of diet, occupation, lifestyle, or other factors. Essentially all men with circulating androgens will develop microscopic prostate cancer if they live long enough. This review is a contemporary and comprehensive, literature-based analysis of the putative risk factors for human prostate cancer, and the results were presented at a multidisciplinary consensus conference held in Crystal City, Virginia, in the fall of 2002. The objectives were to evaluate known environmental factors and mechanisms of prostatic carcinogenesis and to identify existing data gaps and future research needs. The review is divided into four sections, including 1) epidemiology (endogenous factors [family history, hormones, race, aging and oxidative stress] and exogenous factors [diet, environmental agents, occupation and other factors, including lifestyle factors]); 2) animal and cell culture models for prediction of human risk (rodent models, transgenic models, mouse reconstitution models, severe combined immunodeficiency syndrome mouse models, canine models, xenograft models, and cell culture models); 3) biomarkers in prostate cancer, most of which have been tested only as predictive factors for patient outcome after treatment rather than as risk factors; and 4) genotoxic and nongenotoxic mechanisms of carcinogenesis. The authors conclude that most of the data regarding risk relies, of necessity, on epidemiologic studies, but animal and cell culture models offer promise in confirming some important findings. The current understanding of biomarkers of disease and risk factors is limited. An understanding of the risk factors for prostate cancer has practical importance for public health research and policy, genetic and nutritional education and chemoprevention, and prevention strategies.

Prostate Development and Carcinogenesis

The process involved in the development and carcinogenesis of the prostate gland is complex. During early prostate development, the androgenic hormone from embryonic testicles is required for ductal formation, growth, and branching morphogenesis of the prostate gland. From this early stage, interactions between the epithelium and mesenchyme become firmly established through paracrine influence (i.e., growth factors) from mesenchyme (stroma), in response to testosterone, acting on epithelium to stimulate its proliferation, morphogenetic differentiation, and function. In return, the epithelium also exerts its paracrine effects on mesenchyme by regulating the differentiation and specific organizational pattern of its stromal smooth muscle. In a normal adult prostate, the maintenance of normal glandular structure and function is dependent not only on the constant presence of testosterone, but also on a normal intact and stable stroma. This chapter will concentrate first on factors involved in the normal development of the prostate gland and then on the aberrant changes in the homeostatic balance arising either from within (i.e., mutations) or outside (i.e., changes in hormonal balance) that result in derangements of the prostate gland. Finally, environmental and genetic factors that lead to prostate carcinogenesis including activation of oncogenes and mutations of tumor suppressor genes are also discussed.