Tumor necrosis factor alpha negatively regulates the expression of the carcinoma-associated antigen epithelial cell adhesion molecule

Methamphetamine Induces Systemic Inflammation and Anxiety: The Role of the Gut–Immune–Brain Axis

Methamphetamine (METH) is a highly addictive drug abused by millions of users worldwide, thus becoming a global health concern with limited management options. The inefficiency of existing treatment methods has driven research into understanding the mechanisms underlying METH-induced disorders and finding effective treatments. This study aims to understand the complex interactions of the gastrointestinal–immune–nervous systems following an acute METH dose administration as one of the potential underlying molecular mechanisms concentrating on the impact of METH abuse on gut permeability. Findings showed a decreased expression of tight junction proteins ZO-1 and EpCAm in intestinal tissue and the presence of FABP-1 in sera of METH treated mice suggests intestinal wall disruption. The increased presence of CD45+ immune cells in the intestinal wall further confirms gut wall inflammation/disruption. In the brain, the expression of inflammatory markers Ccl2, Cxcl1, IL-1β, TMEM119, and the presence of albumin were higher in METH mice compared to shams, suggesting METH-induced blood–brain barrier disruption. In the spleen, cellular and gene changes are also noted. In addition, mice treated with an acute dose of METH showed anxious behavior in dark and light, open field, and elevated maze tests compared to sham controls. The findings on METH-induced inflammation and anxiety may provide opportunities to develop effective treatments for METH addiction in the future.

Expression and function of epithelial cell adhesion molecule EpCAM: where are we after 40 years?

EpCAM (epithelial cell adhesion molecule) was discovered four decades ago as a tumor antigen on colorectal carcinomas. Owing to its frequent and high expression on carcinomas and their metastases, EpCAM serves as a prognostic marker, a therapeutic target, and an anchor molecule on circulating and disseminated tumor cells (CTCs/DTCs), which are considered the major source for metastatic cancer cells. Today, EpCAM is reckoned as a multi-functional transmembrane protein involved in the regulation of cell adhesion, proliferation, migration, stemness, and epithelial-to-mesenchymal transition (EMT) of carcinoma cells. To fulfill these functions, EpCAM is instrumental in intra- and intercellular signaling as a full-length molecule and following regulated intramembrane proteolysis, generating functionally active extra- and intracellular fragments. Intact EpCAM and its proteolytic fragments interact with claudins, CD44, E-cadherin, epidermal growth factor receptor (EGFR), and intracellular signaling components of the WNT and Ras/Raf pathways, respectively. This plethora of functions contributes to shaping intratumor heterogeneity and partial EMT, which are major determinants of the clinical outcome of carcinoma patients. EpCAM represents a marker for the epithelial status of primary and systemic tumor cells and emerges as a measure for the metastatic capacity of CTCs. Consequentially, EpCAM has reclaimed potential as a prognostic marker and target on primary and systemic tumor cells.

Upregulation of endogenous erythropoietin expression by DLBS6747, a bioactive fraction of Ipomoea batatas L. leaves, via increasing HIF1α transcription factor in HEK293 kidney cells

ETHNOPHARMACOLOGICAL RELEVANCE

Ipomoea batatas L., locally known as ubi jalar, is widely used in Indonesia and other countries as a folk remedy for various chronic diseases, including anemia-associated chronic kidney disease by increasing hematological parameters such as packed cell volume, white blood cells and platelet counts.

AIM OF THE STUDY

The aim of this study is to evaluate the effect of DLBS6747, a bioactive fraction of I. batatas L. leaves, on increasing EPO expression through the upregulation of HIF1α.

MATERIALS AND METHODS

Effect of DLBS6747 on EPO expression and its transcription factor, HIFs, was evaluated in normoxia and hypoxia conditions. Effect of DLBS6747 on several genes involved in EPO expression were evaluated in a time-course manner using conventional and real-time PCR, while the protein level were revealed using western blot and ELISA. The involvement of HIF1α was also confirmed by HIF1α siRNA.

RESULTS

Administration of DLBS6747 increased transcriptional activity of EPO through the regulation of its transcriptional factors, which include HIF1α, HIF2α and NFᴋB. The effect was found to be dependent on oxygen availability, wherein DLBS6747-increased EPO expression was found to be more significant in hypoxic condition. In normoxia and hypoxia, 40 μg/mL DLBS6747 increased HIF1α and HIF2α expressions at mRNA level, wherein the peak appeared in 12 h treatment (up to 7.9- and 8.6-folds, respectively). On the other hand, increased protein level was only found in hypoxia, where the highest HIF1α expression was observed at 6 h (7.5-folds increase) and started to decrease after the hours, while HIF2α was found to be increased time-dependently (up to 13.8-folds in 24 h). The mechanism of action of DLBS6747 as erythropoietin stimulating agent is more likely to affect the regulation of HIF1α, as confirmed by HIF1α siRNA which showed that DLBS6747 failed to increase EPO expression during co-incubation with HIF1α siRNA. DLBS6747 treatment also decreased NFᴋB time-dependently in normoxia, while no NFᴋB was detected in hypoxia, which revealed mimicking hypoxia activity of DLBS6747 to increase EPO expression.

CONCLUSION

These findings showed convincing evidences that DLBS6747 increases endogenous EPO production primarily via upregulation of its transcription factors, especially HIF1α, in human embryonic kidney HEK293 cells. This is the first molecular report that reveals the mechanism of action of natural-based erythropenia drug in different oxygen availability.

Enrichment, Isolation and Molecular Characterization of EpCAM-Negative Circulating Tumor Cells

The presence of EpCAM-positive circulating tumor cells (CTCs) in the peripheral blood is associated with poor clinical outcomes in breast, colorectal and prostate cancer, as well as the prognosis of other tumor types. In addition, recent studies have suggested that the presence of CTCs undergoing epithelial-to-mesenchymal transition and, as such, may exhibit reduced or no expression of epithelial proteins e.g. EpCAM, might be related to disease progression in metastatic breast cancer (MBC) patients. Analyzing the neoplastic nature of this EpCAM-low/negative (EpCAM-neg) subpopulation remains an open issue as the current standard detection methods for CTCs are not efficient at identifying this subpopulation of cells. The possible association of EpCAM-neg CTCs with EpCAM-positive (EpCAM-pos) CTCs and role in the clinicopathological features and prognosis of MBC patients has still to be demonstrated. Several technologies have been developed and are currently being tested for the identification and the downstream analyses of EpCAM-pos CTCs. These technologies can be adapted and implemented into workflows to isolate and investigate EpCAM-neg cells to understand their biology and clinical relevance. This chapter will endeavour to explain the rationale behind the identification and analyses of all CTC subgroups, as well as to review the current strategies employed to enrich, isolate and characterize EpCAM-negative CTCs. Finally, the latest findings in the field will briefly be discussed with regard to their clinical relevance.

LXR agonist T0901317 upregulates thrombomodulin expression in glomerular endothelial cells by inhibition of nuclear factor‑κB

Dysfunction of glomerular endothelial cells (GECs) induces a variety of symptoms, including proteinuria, inflammation, vascular diseases, fibrosis and thrombosis. Thrombomodulin (TM) acts as a vasoprotective molecule on the surface of the vascular endothelial cells to maintain the homeostasis of the endothelial microenvironment by suppressing cellular proliferation, adhesion and inflammatory responses. Liver X receptor (LXR), a nuclear receptor (NR) and a bile acid‑activated transcription factor, regulates metabolism and cholesterol transport, vascular tension and inflammation. Previous studies indicated that TM expression is upregulated by various NRs; however, it is unclear whether pharmacological modulation of LXR may affect TM expression and GEC function. The current study revealed that LXR activation by its agonist, T0901317, upregulates the expression and activity of TM. This effect was mediated specifically through LXR‑α, and not through LXR‑β. Additionally, T0901317 treatment inhibited nuclear factor‑κB (NF‑κB) signaling and the secretion of high glucose‑induced proinflammatory mediators, including tumor necrosis factor‑α and interleukin‑1β in GECs. Co‑immunoprecipitation experiments determined that treatment with T0901317 enhances the interaction between LXR‑α and the transcriptional coactivator, p300, in GEC extracts. The present findings suggest that NF‑κB may be a negative regulator of TM expression, and its removal may contribute to TM gene expression, particularly when in competition with the T0901317‑enhanced formation of the LXR/p300 complex. Therefore, LXR may be a novel molecular target for manipulating TM in GECs, which may advance the treatment of endothelial cell‑associated diseases.

EpCAM is up-regulated by EGF via ERK1/2 signaling and suppresses human epithelial ovarian cancer cell migration

Although epithelial cell adhesion molecule (EpCAM) is overexpressed in human epithelial ovarian cancer (EOC), some contradictory results have been reported regarding the correlation between EpCAM overexpression and patient survival. In addition to this controversy, the function and regulation of EpCAM in EOC remain largely unknown. Here, we show that epidermal growth factor (EGF) up-regulates EpCAM expression by activating ERK1/2 signaling in a human EOC cell line, SKOV3. Additionally, EpCAM overexpression suppresses not only basal but also EGF-stimulated SKOV3 cell migration, whereas EpCAM knockdown increases both basal and EGF-stimulated cell migration in another human EOC cell line, OVCAR4. This study demonstrates the regulation of EpCAM and its role in mediating the effects of EGF on human EOC cell migration.

Fundamental role for HIF-1α in constitutive expression of human β defensin-1

Antimicrobial peptides are secreted by the intestinal epithelium to defend from microbial threats. The role of human β defensin-1 (hBD-1) is notable because its gene (beta-defensin 1 (DEFB1)) is constitutively expressed and its antimicrobial activity is potentiated in the low-oxygen environment that characterizes the intestinal mucosa. Hypoxia-inducible factor (HIF) is stabilized even in healthy intestinal mucosa, and we identified that epithelial HIF-1α maintains expression of murine defensins. Extension to a human model revealed that basal HIF-1α is critical for the constitutive expression of hBD-1. Chromatin immunoprecipitation identified HIF-1α binding to a hypoxia response element in the DEFB1 promoter whose importance was confirmed by site-directed mutagenesis. We used 94 human intestinal samples to identify a strong expression correlation between DEFB1 and the canonical HIF-1α target GLUT1. These findings indicate that basal HIF-1α is critical for constitutive expression of enteric DEFB1 and support targeting epithelial HIF for restoration and maintenance of intestinal integrity.

EpCAM modulates NF-κB signaling and interleukin-8 expression in breast cancer

The epithelial cell adhesion molecule (EpCAM) is a 40-kD type I transmembrane protein that is overexpressed in human epithelial cancers and is currently the target of molecular therapy based on its overexpression at the cell surface. Recently, we and others have shown a role for EpCAM in cell signaling and carcinogenesis, and EpCAM expression seems to promote breast cancer invasion. Interleukin-8 (IL-8/CXCL-8) is an inflammatory cytokine that has recently been shown to modulate breast cancer invasion and angiogenesis. In preliminary experiments, we identified a correlation between EpCAM and IL-8 expression in primary human breast cancers. Specific ablation of EpCAM in breast cancer cell lines results in decreased IL-8 expression, and IL-8 contributes to EpCAM-dependent breast cancer invasion. Specific ablation of EpCAM is also associated with decreased NF-κB transcription factor activity, decreased phosphorylation of the NF-κB family member RELA, and increased IκBα protein expression. EpCAM modulates IL-8 expression at baseline, and following IL-1β stimulation, which is known to be a potent inducer of NF-κB in breast cancer. In functional rescue experiments, specific ablation of RELA or forced expression of the NF-κB inhibitor protein IκBα prevented EpCAM-dependent rescue of IL-8 promoter activity. These studies show for the first time that EpCAM can modulate NF-κB transcription factor activity and IL-8 expression in breast cancer and confirm the role of EpCAM signaling in modulating breast cancer invasion. Further study is required to define the molecular mechanism(s) of EpCAM signaling in breast cancer and to direct the rational development of molecular therapies targeting EpCAM.

Role of excitatory amino acid transporter-2 (EAAT2) and glutamate in neurodegeneration: opportunities for developing novel therapeutics

Glutamate is an essential excitatory neurotransmitter regulating brain functions. Excitatory amino acid transporter (EAAT)-2 is one of the major glutamate transporters expressed predominantly in astroglial cells and is responsible for 90% of total glutamate uptake. Glutamate transporters tightly regulate glutamate concentration in the synaptic cleft. Dysfunction of EAAT2 and accumulation of excessive extracellular glutamate has been implicated in the development of several neurodegenerative diseases including Alzheimer's disease, Huntington's disease, and amyotrophic lateral sclerosis. Analysis of the 2.5  kb human EAAT2 promoter showed that NF-κB is an important regulator of EAAT2 expression in astrocytes. Screening of approximately 1,040 FDA-approved compounds and nutritionals led to the discovery that many β-lactam antibiotics are transcriptional activators of EAAT2 resulting in increased EAAT2 protein levels. Treatment of animals with ceftriaxone (CEF), a β-lactam antibiotic, led to an increase of EAAT2 expression and glutamate transport activity in the brain. CEF has neuroprotective effects in both in vitro and in vivo models based on its ability to inhibit neuronal cell death by preventing glutamate excitotoxicity. CEF increases EAAT2 transcription in primary human fetal astrocytes through the NF-κB signaling pathway. The NF-κB binding site at -272 position was critical in CEF-mediated EAAT2 protein induction. These studies emphasize the importance of transcriptional regulation in controlling glutamate levels in the brain. They also emphasize the potential utility of the EAAT2 promoter for developing both low and high throughput screening assays to identify novel small molecule regulators of glutamate transport with potential to ameliorate pathological changes occurring during and causing neurodegeneration.

Transcription factors and molecular epigenetic marks underlying EpCAM overexpression in ovarian cancer

BACKGROUND

The epithelial cell adhesion molecule (EpCAM) is overexpressed on carcinomas, and its downregulation inhibits the oncogenic potential of multiple tumour types. Here, we investigated underlying mechanisms of epcam overexpression in ovarian carcinoma.

METHODS

Expression of EpCAM and DNA methylation (bisulphite sequencing) was determined for ovarian cancer cell lines. The association of histone modifications and 16 transcription factors with the epcam promoter was analysed by chromatin immunoprecipitation. Treatment with 5-Aza-2'-deoxycytidine (5-AZAC) was used to induce EpCAM expression.

RESULTS

Expression of EpCAM was correlated with DNA methylation and histone modifications. Treatment with 5-AZAC induced EpCAM expression in negative cells. Ten transcription factors were associated with the epcam gene in EpCAM expressing cells, but not in EpCAM-negative cells. Methylation of an Sp1 probe inhibited the binding of nuclear extract proteins in electromobility shift assays; such DNA methylation sensitivity was not observed for an NF-κB probe.

CONCLUSION

This study provides insights in transcriptional regulation of epcam in ovarian cancer. Epigenetic parameters associated with EpCAM overexpression are potentially reversible, allowing novel strategies for sustained silencing of EpCAM expression.

Detection of the circulating tumor cells in cancer patients

As the presence of tumor cells circulating in the blood is associated with systemic disease and shortened survival, the establishment of a method to detect circulating tumor cells (CTCs) is of critical importance for a more concise staging and follow-up of cancer patients. Recently, the most robust strategies for the determination of CTCs are the PCR-based methods and the CellSearch® system that exploits the immunofluorescent characterization and isolation of cancer cells. Herein, we analyzed the experimental strategies used for determining CTCs with respect to accuracy, sensitivity and reproducibility in cancers of the breast, colon, prostate and melanoma.

EpCAM in carcinogenesis: the good, the bad or the ugly

The epithelial cell adhesion molecule (EpCAM) is a membrane glycoprotein that is highly expressed on most carcinomas and therefore of potential use as a diagnostic and prognostic marker for a variety of carcinomas. Interestingly, EpCAM is explored as target in antibody-based therapies. Recently, EpCAM has been identified as an additional marker of cancer-initiating cells. In this review, we describe the controversial biological role of EpCAM with the focus on carcinogenesis: as an adhesion molecule, EpCAM mediates homophilic adhesion interactions, which in turn might prevent metastasis. On the other hand, EpCAM abrogates E-cadherin mediated cell-cell adhesion thereby promoting metastasis. Also, upon cleavage of EpCAM, the intracellular domain functions as a part of a transcriptional complex inducing c-myc and cyclin A and E. In line with these seemingly controversial roles, EpCAM overexpression has been associated with both decreased and increased survival of patients. Similarly, either induction or downregulation of EpCAM expression lowers the oncogenic potential depending on the cell type. As epigenetic dysregulation underlies aberrant EpCAM expression, we propose epigenetic editing as a novel approach to investigate the biological role of EpCAM, expanding the options for EpCAM as a therapeutic target in cancer.

Allogeneic hematopoietic stem cell transplantation for X-linked ectodermal dysplasia and immunodeficiency: case report and review of outcomes

Hypomorphic mutations in nuclear factor kappa B essential modulator (NEMO) cause X-linked ectodermal dysplasia with immunodeficiency (X-ED-ID). Clinical manifestations in boys with X-ED-ID apart from ectodermal dysplasia and immunodeficiency include osteopetrosis, lymphedema, and colitis. Further description of atypical findings in this disorder is needed. Treatment with allogeneic hematopoietic stem cell transplantation (HSCT) is in its infancy, and how or whether non-immune manifestations of defective NEMO function are impacted by HSCT is poorly described. We report an interesting case of a boy with NEMO mutation who had symptoms reminiscent of Omenn's syndrome and small intestinal villous atrophy with features reminiscent of tufting enteropathy. We describe his treatment course as well as reconstitution of immune function and correction of osteopetrosis post-HSCT, and review the cases of allogeneic HSCT reported to date in the literature.

Decreased expression of Ep-CAM protein is significantly associated with the progression and prognosis of oral squamous cell carcinomas in Taiwan

BACKGROUND

The epithelial cell adhesion molecule (Ep-CAM) is involved in cell signaling, migration, proliferation, cell-cycle regulation, and cancer metastasis.

METHODS

This study used an immunohistochemical technique to examine the expression of Ep-CAM protein in 84 specimens of oral squamous cell carcinoma (OSCC), 98 specimens of oral epithelial dysplasia (OED, 31 mild, 41 moderate, and 26 severe OED cases), and 15 specimens of normal oral mucosa (NOM).

RESULTS

We found that the mean Ep-CAM labeling indices (LIs) decreased significantly from NOM (80 +/- 18%) and mild OED (76 +/- 14%) through moderate OED (66 +/- 22%) and severe OED (55 +/- 20%) to OSCC samples (46 +/- 16%, P < 0.001). A significant correlation was found between the lower mean Ep-CAM LI and OSCCs with larger tumor size (P = 0.003), positive lymph node metastasis (P = 0.022), more advanced clinical stages (P < 0.001), cancer recurrence (P = 0.021), or extracapsular spread of lymph node (P = 0.015). However, only Ep-CAM LI < 50% (P < 0.0001) was identified as an independent unfavorable prognosis factor by multivariate analyses with Cox proportional hazard regression model. Kaplan-Meier curve showed that OSCC patients with an Ep-CAM LI < 50% had a significantly poorer cumulative survival than those with an Ep-CAM LI > or = 50% (P < 0.00001, log-rank test).

CONCLUSIONS

We conclude that the decreased expression of Ep-CAM protein is an early event in oral carcinogenesis. The Ep-CAM LI in OSCC samples can predict the progression of OSCCs and the survival of OSCC patients.

Spatial and temporal expression patterns of the epithelial cell adhesion molecule (EpCAM/EGP-2) in developing and adult kidneys

BACKGROUND

The epithelial cell adhesion molecule (EpCAM) is expressed by most epithelia and is involved in processes fundamental for morphogenesis, including cell-cell adhesion, proliferation, differentiation, and migration. Previously, a role for EpCAM in pancreatic morphogenesis was confirmed in vitro. Furthermore, changes in the EpCAM expression pattern were found in developing lung and thymus and in the regenerating liver. Therefore, EpCAM was proposed to be a morphoregulatory molecule.

METHODS

Using immunohistochemistry, the expression pattern of human and murine homologues of EpCAM was characterized in adult and embryonic kidneys from humans and human-EpCAM (hEpCAM)-transgenic mice.

RESULTS

EpCAM expression was found in the ureteric bud throughout nephrogenesis. EpCAM was not expressed in the metanephric mesenchyme. In comma- and S-shaped bodies, both metanephric mesenchyme derived structures, EpCAM expression appeared by E13.5. In adult kidneys, most epithelia expressed varying levels of EpCAM, as confirmed by double staining for human EpCAM and segment-specific nephron markers. Podocytes were EpCAM negative. At the cellular level, the EpCAM expression shifted from apical in embryonic to basolateral in adult kidneys.

CONCLUSIONS

The spatiotemporal expression pattern of EpCAM changes during nephrogenesis. In the adult kidney, the expression varies markedly along the nephron. These data provide a basis for further studies on EpCAM in developing and adult kidneys.

Epithelial cell adhesion molecule: more than a carcinoma marker and adhesion molecule

The epithelial cell adhesion molecule (EpCAM, CD326) is a glycoprotein of approximately 40 kd that was originally identified as a marker for carcinoma, attributable to its high expression on rapidly proliferating tumors of epithelial origin. Normal epithelia express EpCAM at a variable but generally lower level than carcinoma cells. In early studies, EpCAM was proposed to be a cell-cell adhesion molecule. However, recent insights revealed a more versatile role for EpCAM that is not limited only to cell adhesion but includes diverse processes such as signaling, cell migration, proliferation, and differentiation. Cell surface expression of EpCAM may actually prevent cell-cell adhesion. Here, we provide a comprehensive review of the current knowledge on EpCAM biology in relation to other cell adhesion molecules. We discuss the implications of the newly identified functions of EpCAM in view of its prognostic relevance in carcinoma, inflammatory pathophysiology, and tissue development and regeneration as well as its role in normal epithelial homeostasis.

Erythropoietin production: Molecular mechanisms of the antagonistic actions of cyclic adenosine monophosphate and interleukin-1

Erythropoietin (Epo) mRNA expression is suppressed by interleukin 1 (IL-1). Cyclic adenosine monophosphate (cAMP) can increase Epo mRNA and Epo protein levels in IL-1 treated HepG2 cells to some extent. To identify molecular mechanisms of this reaction we investigated three transcription factors (NF-kappaB, GATA-2 and HIF-1) that control the Epo gene. Western blot analyses and electrophoretic mobility shift assays (EMSAs) revealed that IL-1 strongly activated NF-kappaB, which is a likely suppressor of the Epo promoter. Treatment of the cells with dibutyryl-cAMP (Bt2-cAMP) inhibited the activation of NF-kappaB by IL-1. Bt2-cAMP increased GATA-2 DNA binding. Since GATA-2 is a suppressor of the Epo promoter, GATA-2 activation was unlikely to cause the increase of Epo mRNA expression in IL-1 treated cells. Furthermore, Western blots, EMSAs and reporter gene studies showed that Bt2-cAMP was without effect on the hypoxia-inducible transcription factor HIF-1. Thus, NF-kappaB is probably the primary transcription factor by which cAMP counteracts the inhibition of Epo gene expression by IL-1.

Methylation status of the Ep-CAM promoter region in human breast cancer cell lines and breast cancer tissue

We examined the methylation status of the Ep-CAM promoter region of human breast cancer cell lines and breast cancer tissue using MethyLight technology and bisulfite sequencing. We found the promoter of Ep-CAM-negative breast cancer cell lines Hs 578T to be methylated to a higher degree as compared to positive cell lines MCF-7. Demethylation of cell lines was performed using 5-aza-2'-deoxycytidine. Ep-CAM RNA and protein expression could be partially restored by treating cells with 5-Aza-2'-deoxycytidine. In most primary breast cancer tissue, methylation of the Ep-CAM gene could be detected at a low level and no correlation was found with Ep-CAM protein expression in tumour tissue. Taken together, these data suggest that methylation of the Ep-CAM promoter is not a crucial mechanism for regulation of Ep-CAM expression in breast cancer. Thus, most important regulatory mechanisms have to be supposed in vivo.

Frequent high-level expression of the immunotherapeutic target Ep-CAM in colon, stomach, prostate and lung cancers

Epithelial cell adhesion molecule (Ep-CAM; CD326) is used as a target by many immunotherapeutic approaches, but little data are available about Ep-CAM expression in major human malignancies with respect to level, frequency, tumour stage, grade, histologic tumour type and impact on survival. We analysed by immunohistochemical staining tissue microarrays with 4046 primary human carcinoma samples from colon, stomach, prostate and lung cancers for both frequency and intensity of Ep-CAM expression under highly standardised conditions. A total of 3360 samples were analysable. High-level Ep-CAM expression was observed in 97.7% (n=1186) of colon, 90.7% of gastric (n=473), and 87.2% of prostate cancers (n=414), and in 63.9% of lung cancers (n=1287). No detectable Ep-CAM staining was found with only 0.4% of colon, 2.5% of gastric, 1.9% of prostate cancers, and 13.5% of lung cancers. The only significant correlation of Ep-CAM expression with tumour grading was observed in colon cancer where high-level Ep-CAM expression on grade 3 tumours was down to 92.1% (P<0.0001). Adenosquamous and squamous carcinomas of the lung had a lower percentage of high-level Ep-CAM expression compared to adenocarcinomas with 35.4 and 53.6%, respectively, and with 45.5 and 17.3% of tumours being Ep-CAM negative. With the exception of moderately differentiated colon carcinoma, where patients not expressing Ep-CAM on their tumours showed an inferior survival (P=0.0014), correlation of Ep-CAM expression with survival did not reach statistical significance for any of the other cancer indications and subgroups. In conclusion, the data strongly support the notion that Ep-CAM is a prime target for immunotherapies in major human malignancies. This is because the most common human cancers show (i) a low frequency of Ep-CAM-negative tumours, (ii) a high frequency of Ep-CAM expression on cells of a given tumour, and (iii) for most cancers, an insignificant influence of tumour staging, grading and histology on Ep-CAM expression.

Trifunctional bispecific antibody-induced tumor cell lysis of squamous cell carcinomas of the upper aerodigestive tract

BACKGROUND

The trifunctional bispecific antibody Removab (tbAB) bridges and activates CD3 positive T cells to EpCAM on carcinoma cells and simultaneously binds to an accessory immune-cell inducing tumor cell lysis. tbAB-induced tumor cytotoxicity was assessed in an autologous human ex vivo system.

METHODS

One hundred forty tumor samples and autologous peripheral blood mononuclear cells from a total of 36 patients with head and neck squamous cell carcinomas (HNSCCs) were incubated on a chicken embryo chorioallantois membrane with Removab. Tumor cells coincubated with cisplatin or cell culture medium served as positive and negative controls. Tumor cell lysis was assessed by acridine orange staining or by fluorescence-activated cell sorting of propidium iodide-marked cells after 24 and 48 hours (T24/T48) coincubation.

RESULTS

Coincubation of HNSCC cells with tbAB and autologous peripheral blood mononuclear cells resulted in a 49% +/- 6% decrease of viable cells at T24 (p < .005) and in a decrease of 56% +/- 8% at T48 (p < .005) compared with the control. The tumor cytotoxicity was similar to that of cisplatin (49% +/- 7% decrease at T24 and 49% +/- 8% at T48).

CONCLUSION

In an autologous human ex vivo system, the tbAB-induced tumor cell lysis was comparable to that by cisplatin.

EGP-314 is expressed differentially in three brain zones at an early time in an experimentally induced ischemia rat model

Gene expression in frontal, occipital, and hippocampal regions of rat brains at 15 min of ischemic injury was studied in a rat model by producing focal cerebral ischemia through middle cerebral artery (MCA) occlusion without reperfusion. Catalase, epithelial glycoprotein (EGP-314), cytochrome C oxidase-subunit 1, ribosomal L31 protein, and ceruloplasmin were found to be differentially expressed. Specific primers were designed to study this newly reported brain EGP-314, a cellular adhesion molecule involved in cell-cell and cell-extracellular matrix interactions and related with cytoskeletal organization, differentiation, and proliferation. In the frontal and occipital lobes, EGP-314 expression was low in control and ischemic conditions and increased in sham injured conditions, whereas in the hippocampal region its expression was induced only by ischemia. In situ hybridization and immunohistochemistry revealed that EGP-314 mRNA and the protein were present in the ischemic hippocampus pyramidal neurons. DNA fragmentation was demonstrated by TUNEL and LM-PCR analysis in hippocampus region. TUNEL positive pyramidal neurons were observed at 15 min of ischemia. DNA ladder was found at 12 and 15 min of ischemia.

Regulation of endothelial thrombomodulin expression by inflammatory cytokines is mediated by activation of nuclear factor-kappa B

Inflammation and thrombosis are increasingly recognized as interrelated biologic processes. Endothelial cell expression of thrombomodulin (TM), a key component of the anticoagulant protein C pathway, is potently inhibited by inflammatory cytokines. Because the mechanism underlying this effect is largely unknown, we investigated a potential role for the inflammatory transcription factor nuclear factor-kappa B (NF-κB). Blocking NF-κB activation effectively prevented cytokine-induced down-regulation of TM, both in vitro and in a mouse model of tumor necrosis factor-α (TNF-α)–mediated lung injury. Although the TM promoter lacks a classic NF-κB consensus site, it does contain tandem Ets transcription factor binding sites previously shown to be important for both constitutive TM gene expression and cytokine-induced repression. Using electrophoretic mobility shift assay and chromatin immunoprecipitation, we found that multiple Ets species bind to the TNF-α response element within the TM promoter. Although cytokine exposure did not alter Ets factor binding, it did reduce binding of p300, a coactivator required by Ets for full transcriptional activity. Overexpression of p300 also prevented TM repression by cytokines. We conclude that NF-κB is a critical mediator of TM repression by cytokines. Further evidence suggests a mechanism involving competition by NF-κB for limited pools of the transcriptional coactivator p300 necessary for TM gene expression.

Identification of an epitope from the epithelial cell adhesion molecule eliciting HLA-A*2402-restricted cytotoxic T-lymphocyte responses

Because the epithelial cell adhesion molecule (Ep-CAM) is expressed in almost all carcinomas and human leucocyte antigen (HLA)-A*2402 is the most common allele in many ethnic groups, including Japanese, the identification of peptide sequences, which elicit HLA-A*2402-restricted Ep-CAM-specific cytotoxic T-lymphocyte (CTL) responses, would facilitate specific immunotherapy for various histological types of carcinomas. An epitope was identified through the following steps: (i) computer-based epitope prediction from the amino acid sequence of Ep-CAM, (ii) major histocompatibility complex (MHC) stabilization assay to determine the affinity of the predicted peptide with HLA-A*2402 molecules, (iii) stimulation of CD8+ T cells with peptide-pulsed dendritic cells and (iv) testing the CTL specificity by means of enzyme-linked immunospot (ELISPOT) assays, CTL assays and MHC/peptide-tetramer staining. Peripheral CD8+ T cells of four of five healthy donors after three rounds of stimulation with the peptide Ep-CAM173-181 (RYQLDPKFI) secreted interferon-gamma in ELISPOT assays when exposed to the peptide. A CTL clone specific to the peptide efficiently lysed Ep-CAM-expressing cancer cell lines in an HLA-A*2402-restricted fashion. Endogenous processing and presentation of the peptide in a lung cancer cell line were confirmed by means of cold target inhibition assays. The CTL clone was also lytic to normal bronchial epithelial cells but to a lesser extent at low effector: target ratios. All these data suggest that the peptide-specific CTL responses may play some roles both in anti-cancer and autoimmune reactions. The peptide should prove useful to study anti-Ep-CAM CTL responses among population possessing HLA-A*2402.

Enrichment methods to detect bone marrow micrometastases in breast carcinoma patients: clinical relevance

Introduction

Improving technologies for the detection and purification of bone marrow (BM) micrometastatic cells in breast cancer patients should lead to earlier prognosis of the risk of relapse and should make it possible to design more appropriate therapies. The technique used has to overcome the challenges resulting from the small number of target cells (one per million hematopoietic cells) and the heterogeneous expression of micrometastatic cell markers. In the present study, we have assessed the clinical relevance of current methods aimed at detecting rare disseminated carcinoma cells.

Methods

BM aspirates from 32 carcinoma patients were screened for the presence of micrometastatic cells positive for epithelial cell adhesion molecule and positive for cytokeratins, using optimized immunodetection methods. A comparison with data obtained for 46 control BM aspirates and a correlation with the clinical status of patients were performed.

Results

We developed a sensitive and efficient immunomagnetic protocol for the enrichment of BM micrometastases. This method was used to divide 32 breast carcinoma patients into three categories according to their epithelial cell adhesion molecule status. These categories were highly correlated with the recently revised American Joint Committee on Cancer staging system for breast cancer, demonstrating the clinical relevance of this simple and reliable immunomagnetic technique. We also evaluated immunocytochemical detection of cytokeratin-positive cells and cytomorphological parameters. Immunocytochemistry-based methods for the detection of BM micrometastases did not provide any information about the clinical status of patients, but helped to refine the immunomagnetic data by confirming the presence of micrometastases in some cases. We also tested a new density gradient centrifugation system, able to enrich the tumor fraction of BM specimens by twofold to threefold as compared with standard Ficoll methods.

Conclusion

These improved methods for the detection of micrometastatic cells in patient BM should help clinicians to predict the clinical status of breast cancer patients at the time of surgery or treatment.

Use of the EGP-2/Ep-CAM promoter for targeted expression of heterologous genes in carcinoma derived cell lines

EGP-2, also known as Ep-CAM, is expressed at high levels on the surface of most carcinomas and is therefore considered an attractive target for anticancer strategies. To explore the mechanisms regulating the expression of EGP-2, sequences 3.4 kb upstream of the transcription start site were isolated and assayed for their ability to control the expression of the EGP-2 cDNA, the green fluorescent protein, the luciferase reporter gene and the thymidine kinase and cytosine deaminase suicide genes. Expression of these chimeric constructs as assessed in a range of different cell lines was restricted to cell lines expressing EGP-2. In addition, only cells expressing EGP-2 were sensitive for gancyclovir after being transiently transfected with EGP-2 promoter-driven thymidine kinase. Deletion analyses defined 687 bp upstream as the basic proximal promoter region, which could confer epithelial-specific expression to the GFP reporter gene in vitro. As these EGP-2 sequences can confer promoter activity to reporter and suicide genes in an EGP-2 restricted manner, they may be useful for gene therapy of EGP-2 expressing carcinomas.

Tumor necrosis factor-alpha activates NFkappaB to inhibit renin transcription by targeting cAMP-responsive element

Tumor necrosis factor-alpha (TNFalpha) is known to inhibit renin gene expression in juxtaglomerular cells, which are the main source of renin in vivo. In the present study we aimed to characterize the intracellular mechanisms of TNFalpha signaling to renin gene in the mouse juxtaglomerular cell line As4.1. TNFalpha was found to activate NFkappaB, which is one of the principal intracellular mediators of TNFalpha signal transduction. Constitutive activation of NFkappaB suppressed renin gene transcription, but NFkappaB appeared not to target the NFkappaB binding sites in the renin promoter. Thus, NFkappaB, but not the canonical NFkappaB binding sequences in the renin promoter, seemed to be involved in the suppression of renin transcription by TNFalpha. Deletion/mutation analysis revealed that the effect of TNFalpha on renin gene is transmitted by a cAMP-responsive element (CRE) located at -2697 to -2690. Mobility shift/supershift assays evidenced for the presence of NFkappaB proteins in the complex that binds to mouse renin CRE. Our results strongly suggest that NFkappaB mediates the effect of TNFalpha on renin transcription targeting a CRE in the mouse renin promoter.

Tumor-specific glycosylation of the carcinoma-associated epithelial cell adhesion molecule EpCAM in head and neck carcinomas

The tissue-specific glycosylation of the carcinoma (CA)-associated antigen epithelial cell adhesion molecule (EpCAM) was studied in 60 patients suffering from head and neck CAs, and 26 pairs of autologous healthy thyroid and CA biopsies. EpCAM was glycosylated in all tumor samples in which its expression was detectable (73%). Additionally, in 80.7% of patients, tumor-derived EpCAM was heavily glycosylated while EpCAM derived from autologous thyroid was not (76.2%) or weakly (23.8%). Four cases showed a similar glycosylation pattern (15.3%) and one case displayed a reverse pattern (3.8%). Additionally, the expression and glycosylation of EpCAM were assessed in tumor adjacent and distant tissue. EpCAM was glycosylated in tumor-adjacent while it was not or only weakly expressed in tumor distant tissue where it was unglycosylated. Thus, EpCAM is differentially glycosylated in healthy tissue and tumor cells of the head and neck area.

Inhibition of erythropoietin gene expression signaling involves the transcription factors GATA-2 and NF-kappaB

The anemia of chronic inflammatory and malignant diseases is partly due to impaired synthesis of the hormone erythropoietin (Epo). The proinflammatory cytokines interleukin-1 (IL-1) and tumor necrosis factor a (TNF-alpha) suppress in vitro Epo gene expression and Epo protein secretion. However, the molecular mechanisms of this inhibition are poorly understood. The human Epo promoter and the 5' flanking region contain several recognition sequences for transcription factors acting either positively or negatively. Herein, we investigated the roles of the transcription factors GATA-2 and NF-kappaB in the modulation of Epo gene expression by IL-1beta and TNF-alpha in the human hepatoma cell line HepG2. Electrophoretic mobility shift assays revealed increased GATA-2 and NF-kappaB DNA binding in cells treated with IL-1beta or TNF-alpha. Reporter gene assays with a sequence from the Epo promoter in front of the firefly luciferase gene showed that the cytokines reduced Epo reporter gene activity. Functional inactivation of GATA-2 and NF-kappaB by oligo-decoy techniques prevented the inhibition of Epo production by IL-1beta and TNF-alpha. In HepG2 cells stably transfected with a dominant-negative form of IkappaBalpha, the activation of NF-kappaB was inhibited, while Epo mRNA levels and Epo secretion increased. Thus, both GATA-2 and NF-kappaB seem to be involved in the suppression of Epo gene expression by IL-1beta and TNF-alpha in vitro and may be responsible for impaired Epo synthesis in inflammatory diseases in vivo.