Epithelial cell adhesion molecule (EpCAM) is overexpressed in breast cancer metastases

Exploring novel circulating biomarkers for liver cancer through extracellular vesicle characterization with infrared spectroscopy and plasmonics

BACKGROUND

Hepatocellular carcinoma (HCC) is the most common form of liver cancer, with cirrhosis being a major risk factor. Traditional blood markers like alpha-fetoprotein (AFP) demonstrate limited efficacy in distinguishing between HCC and cirrhosis, underscoring the need for more effective diagnostic methodologies. In this context, extracellular vesicles (EVs) have emerged as promising candidates; however, their practical diagnostic application is restricted by the current lack of label-free methods to accurately profile their molecular content. To address this gap, our study explores the potential of mid-infrared (mid-IR) spectroscopy, both alone and in combination with plasmonic nanostructures, to detect and characterize circulating EVs.

RESULTS

EVs were extracted from HCC and cirrhotic patients. Mid-IR spectroscopy in the Attenuated Total Reflection (ATR) mode was utilized to identify potential signatures for patient classification, highlighting significant changes in the Amide I-II region (1475-1700 cm-1). This signature demonstrated diagnostic performance comparable to AFP and surpassed it when the two markers were combined. Further investigations utilized a plasmonic metasurface suitable for ultrasensitive spectroscopy within this spectral range. This device consists of two sets of parallel rod-shaped gold nanoantennas (NAs); the longer NAs produced an intense near-field amplification in the Amide I-II bands, while the shorter NAs were utilized to provide a sharp reflectivity edge at 1800-2200 cm-1 for EV mass-sensing. A clinically relevant subpopulation of EVs was targeted by conjugating NAs with an antibody specific to Epithelial Cell Adhesion Molecule (EpCAM). This methodology enabled the detection of variations in the quantity of EpCAM-presenting EVs and revealed changes in the Amide I-II lineshape.

SIGNIFICANCE

The presented results can positively impact the development of novel laboratory methods for the label-free characterization of EVs, based on the combination between mid-IR spectroscopy and plasmonics. Additionally, data obtained by using HCC and cirrhotic subjects as a model system, suggest that this approach could be adapted for monitoring these conditions.

Regulation of the Function and Expression of EpCAM

The epithelial cell adhesion molecule (EpCAM) is a single transmembrane protein on the cell surface. Given its strong expression on epithelial cells and epithelial cell-derived tumors, EpCAM has been identified as a biomarker for circulating tumor cells (CTCs) and exosomes and a target for cancer therapy. As a cell adhesion molecule, EpCAM has a crystal structure that indicates that it forms a cis-dimer first and then probably a trans-tetramer to mediate intercellular adhesion. Through regulated intramembrane proteolysis (RIP), EpCAM and its proteolytic fragments are also able to regulate multiple signaling pathways, Wnt signaling in particular. Although great progress has been made, increasingly more findings have revealed the context-specific expression and function patterns of EpCAM and their regulation processes, which necessitates further studies to determine the structure, function, and expression of EpCAM under both physiological and pathological conditions, broadening its application in basic and translational cancer research.

Context-dependent roles for ubiquitous mitochondrial creatine kinase CKMT1 in breast cancer progression

Metabolic reprogramming is a hallmark of cancer, enabling cancer cells to rapidly proliferate, invade, and metastasize. We show that creatine levels in metastatic breast cancer cell lines and secondary metastatic tumors are driven by the ubiquitous mitochondrial creatine kinase (CKMT1). We discover that, while CKMT1 is highly expressed in primary tumors and promotes cell viability, it is downregulated in metastasis. We further show that CKMT1 downregulation, as seen in breast cancer metastasis, drives up mitochondrial reactive oxygen species (ROS) levels. CKMT1 downregulation contributes to the migratory and invasive potential of cells by ROS-induced upregulation of adhesion and degradative factors, which can be reversed by antioxidant treatment. Our study thus reconciles conflicting evidence about the roles of metabolites in the creatine metabolic pathway in breast cancer progression and reveals that tight, context-dependent regulation of CKMT1 expression facilitates cell viability, cell migration, and cell invasion, which are hallmarks of metastatic spread.

CAR-based immunotherapy for breast cancer: peculiarities, ongoing investigations, and future strategies

Surgery, chemotherapy, and endocrine therapy have improved the overall survival and postoperative recurrence rates of Luminal A, Luminal B, and HER2-positive breast cancers but treatment modalities for triple-negative breast cancer (TNBC) with poor prognosis remain limited. The effective application of the rapidly developing chimeric antigen receptor (CAR)-T cell therapy in hematological tumors provides new ideas for the treatment of breast cancer. Choosing suitable and specific targets is crucial for applying CAR-T therapy for breast cancer treatment. In this paper, we summarize CAR-T therapy's effective targets and potential targets in different subtypes based on the existing research progress, especially for TNBC. CAR-based immunotherapy has resulted in advancements in the treatment of breast cancer. CAR-macrophages, CAR-NK cells, and CAR-mesenchymal stem cells (MSCs) may be more effective and safer for treating solid tumors, such as breast cancer. However, the tumor microenvironment (TME) of breast tumors and the side effects of CAR-T therapy pose challenges to CAR-based immunotherapy. CAR-T cells and CAR-NK cells-derived exosomes are advantageous in tumor therapy. Exosomes carrying CAR for breast cancer immunotherapy are of immense research value and may provide a treatment modality with good treatment effects. In this review, we provide an overview of the development and challenges of CAR-based immunotherapy in treating different subtypes of breast cancer and discuss the progress of CAR-expressing exosomes for breast cancer treatment. We elaborate on the development of CAR-T cells in TNBC therapy and the prospects of using CAR-macrophages, CAR-NK cells, and CAR-MSCs for treating breast cancer.

Context-Responsive Nanoparticle Derived from Synthetic Zwitterionic Ionizable Phospholipids in Targeted CRISPR/Cas9 Therapy for Basal-like Breast Cancer

The majority of triple negative breast cancers (TNBCs) are basal-like breast cancers (BLBCs), which tend to be more aggressive, proliferate rapidly, and have poor clinical outcomes. A key prognostic biomarker and regulator of BLBC is the Forkhead box C1 (FOXC1) transcription factor. However, because of its functional placement inside the cell nucleus and its structural similarity with other related proteins, targeting FOXC1 for therapeutic benefit, particularly for BLBC, continues to be difficult. We envision targeted nonviral delivery of CRISPR/Cas9 plasmid toward the efficacious knockdown of FOXC1. Keeping in mind the challenges associated with the use of CRISPR/Cas9 in vivo, including off-targeting modifications, and effective release of the cargo, a nanoparticle with context responsive properties can be designed for efficient targeted delivery of CRISPR/Cas9 plasmid. Consequently, we have designed, synthesized, and characterized a zwitterionic amino phospholipid-derived transfecting nanoparticle for delivery of CRISPR/Cas9. The construct becomes positively charged only at low pH, which encourages membrane instability and makes it easier for nanoparticles to exit endosomes. This has enabled effective in vitro and in vivo downregulation of protein expression and genome editing. Following this, we have used EpCAM aptamer to make the system targeted toward BLBC cell lines and to reduce its off-target toxicity. The in vivo efficacy, biodistribution, preliminary pharmacokinetics, and biosafety of the optimized targeted CRISPR nanoplatform is then validated in a rodent xenograft model. Overall, we have attempted to knockout the proto-oncogenic FOXC1 expression in BLBC cases by efficient delivery of CRISPR effectors via a context-responsive nanoparticle delivery system derived from a designer lipid derivative. We believe that the nonviral approach for in vitro and in vivo delivery of CRISPR/Cas9 targeted toward FOXC1, studied herein, will greatly emphasize the therapeutic regimen for BLBC.

Photo-functionalized TiO2 film for facile immobilization of EpCAM antibodies and efficient enrichment of circulating tumor cells

The highly efficient capture of circulating tumor cells (CTCs) in the blood is essential for the screening, treatment, and assessment of the risk of metastasis or recurrence of cancer. Immobilizing specific antibodies, such as EpCAM antibodies, on the material's surface is currently the primary method for efficiently capturing CTCs. However, the strategies for immobilizing antibodies usually have the disadvantages of requiring multiple chemical reagents and a complex pre-treatment process. Herein we developed a simple strategy for the immobilization of EpCAM antibodies without additional chemical reagents. By utilizing the positive charge property of the photo-functionalized titanium dioxide (TiO₂), the negatively charged carboxyl terminal of EpCAM antibodies was immobilized by electrostatic interaction, allowing the antibodies to expose the antigen binding site fully. The experimental results showed that the photo-functionalized TiO₂ surface had a marked positive charge and super-hydrophilic properties that could immobilize large amounts of EpCAM antibodies and keep excellent activity. CTCs capture experiments in vitro showed that the EpCAM antibodies-modified photo-functionalized TiO₂ could efficiently capture CTCs. The results of blood circulation experiments in rabbits showed that the EpCAM antibodies-modified photo-functionalized TiO₂ could accurately capture CTCs from the whole body's blood. It was foreseen that the strategy of simple immobilization of EpCAM antibodies based on photo-functionalized TiO₂ is expected to serve in the efficient capture of CTCs in the future.

The association between Annexin A2 and epithelial cell adhesion molecule in breast cancer cells

BACKGROUND

The epithelial cell adhesion molecule (EpCAM) is a type I transmembrane and glycosylated protein, which is overexpressed in many neoplasms. However, EpCAM has no known ligand partners and the mechanisms by which it functions are not fully understood.

AIM

This study was performed to discover novel partners of EpCAM, which may provide a better understanding of its functions.

METHODS

The membrane fraction of the ERα+ noninvasive breast cancer cell line ZR-75-1 and MCF-7 was extracted and followed by co-immunoprecipitation of EpCAM using C-10, a mouse monoclonal antibody raised against amino acids 24-93 of the EpCAM molecule. As a negative control, MDA-MB-231 and Hs578T were used since they express a negligible amount of EpCAM and are known as EpCAM-/low ERα-/low invasive and tumorigenic breast cancer cell lines.

RESULTS

Annexin A2 (ANXA2) was found to be selectively and differentially co-immunoprecipitated with EpCAM in the ERα+ breast cancer cells MCF-7 and ZR-75-1. ANXA2 is a multifunctional protein and known to act as a co-receptor for tissue plasminogen activator (tPA) on the surface of endothelial and cancer cells, thereby affecting fibrinolytic activity and neoangiogenesis as well as invasive and metastatic properties. In this study, the association between EpCAM and ANXA2 was found to affect the activity of tPA.

CONCLUSION

This study concludes that ANXA2 co-localizes with EpCAM at the plasma membrane, and the co-localization may have functional implications. Data suggest that EpCAM supports ANXA2 to function as a co-receptor for the tPA, and that EpCAM has a regulatory function on the expression and subcellular localization of ANXA2.

The Predictive Role of Serum Levels of Soluble Cell Adhesion Molecules (sCAMs) in the Therapy of Advanced Breast Cancer—A Single-Centre Study

Background and Objectives: Soluble cell adhesion molecules (sCAMs) play a significant role in the metastatic potential of breast cancer (BC). They might block lymphocytes and promote angiogenesis and migration of cancer cells. We assessed the usefulness of sCAMs in the prognosis and monitoring of the progression of advanced BC. Materials and Methods: We assessed soluble E-selectin, P-selectin, VCAM-1, ICAM-1, EpCAM, IL-6Ra, TNF-R1, and TNF-R2 in 39 women with aBC. Blood samples were obtained at the beginning of the treatment and after 2 months. Results: The median progression-free survival (PFS) was 9 months, and overall survival (OS) was 27 months. The higher levels of sICAM-1 (HR = 2.60, p = 0.06) and lower levels of sEpCAM (HR = 2.72, p < 0.05) were associated with faster progression of aBC. High levels of sEpCAM through the follow-up period were significantly associated with a lower risk of progression (HR = 0.40, p < 0.01). We found the independent predictive value of higher than median sICAM-1 levels for PFS (HR = 2.07, p = 0.08) and of sVCAM-1 levels for OS (HR = 2.59, p < 0.05). Conclusions: Our data support the predictive value of sICAM-1 and sVCAM-1 and suggest that they could become markers for tailoring new therapies in aBC. sEpCAM level could be used as an early indicator of response to the therapy.

Drug Delivery of Natural Products Through Nanocarriers for Effective Breast Cancer Therapy: A Comprehensive Review of Literature

Despite recent advances in the diagnosis and treatment of breast cancer (BC), it remains a global health issue affecting millions of women annually. Poor prognosis in BC patients is often linked to drug resistance as well as the lack of effective therapeutic options for metastatic and triple-negative BC. In response to these unmet needs, extensive research efforts have been devoted to exploring the anti-BC potentials of natural products owing to their multi-target mechanisms of action and good safety profiles. Various medicinal plant extracts/essential oils and natural bioactive compounds have demonstrated anti-cancer activities in preclinical BC models. Despite the promising preclinical results, however, the clinical translation of natural products has often been hindered by their poor stability, aqueous solubility and bioavailability. There have been attempts to overcome these limitations, particularly via the use of nano-based drug delivery systems (NDDSs). This review highlights the tumour targeting mechanisms of NDDSs, the advantages and disadvantages of the major classes of NDDSs and their current clinical status in BC treatment. Besides, it also discusses the proposed anti-BC mechanisms and nanoformulations of nine medicinal plants' extracts/essential oils and nine natural bioactive compounds; selected via the screening of various scientific databases, including PubMed, Scopus and Google Scholar, based on the following keywords: "Natural Product AND Nanoparticle AND Breast Cancer". Overall, these nanoformulations exhibit improved anti-cancer efficacy against preclinical BC models, with some demonstrating biocompatibility with normal cell lines and mouse models. Further clinical studies are, however, warranted to ascertain their efficacy and biocompatibility in humans.

Clinical importance of high-mannose, fucosylated and complex N-glycans in breast cancermetastasis

BACKGROUND. Although aberrant glycosylation is recognized as a hallmark of cancer, glycosylation in clinical breast cancer (BC) metastasis has not yet been studied. While preclinical studies show that the glycocalyx coating of cancer cells is involved in adhesion, migration, and metastasis, glycosylation changes from primary tumor (PT) to various metastatic sites remain unknown in patients.

METHODS. We investigated N-glycosylation profiles in 17 metastatic BC patients from our rapid autopsy program. Primary breast tumor, lymph node metastases, multiple systemic metastases, and various normal tissue cores from each patient were arranged on unique single-patient tissue microarrays (TMAs). We performed mass spectrometry imaging (MSI) combined with extensive pathology annotation of these TMAs, and this process enabled spatially differentiated cell-based analysis of N-glycosylation patterns in metastatic BC.

RESULTS. N-glycan abundance increased during metastatic progression independently of BC subtype and treatment regimen, with high-mannose glycans most frequently elevated in BC metastases, followed by fucosylated and complex glycans. Bone metastasis, however, displayed increased core-fucosylation and decreased high-mannose glycans. Consistently, N-glycosylated proteins and N-glycan biosynthesis genes were differentially expressed during metastatic BC progression, with reduced expression of mannose-trimming enzymes and with elevated EpCAM, N-glycan branching, and sialyation enzymes in BC metastases versus PT.

CONCLUSION. We show in patients that N-glycosylation of breast cancer cells undergoing metastasis occurs in a metastatic site–specific manner, supporting the clinical importance of high-mannose, fucosylated, and complex N-glycans as future diagnostic markers and therapeutic targets in metastatic BC.

FUNDING. NIH grants R01CA213428, R01CA213492, R01CA264901, T32CA193145, Dutch Province Limburg “LINK”, European Union ERA-NET TRANSCAN2-643638.

Breast Cancer Aptamers: Current Sensing Targets, Available Aptamers, and Their Evaluation for Clinical Use in Diagnostics

Breast cancer is the most commonly occurring cancer in women worldwide, and the rate of diagnosis continues to increase. Early detection and targeted treatment towards histological type is crucial to improving outcomes, but current screening methods leave some patients at risk of late diagnosis. The risk of late diagnosis and progressed disease is of particular concern for young women as current screening methods are not recommended early in life. Aptamers are oligonucleotides that can bind with high specificity to target molecules such as proteins, peptides, and other small molecules. They are relatively cheap to produce and are invariable from batch to batch, making them ideal for use in large-scale clinical or screening programs. The use of aptamers for breast cancer screening, diagnosis, and therapeutics is promising, but comparison of these aptamers and their corresponding biomarkers for use in breast cancer is significantly lacking. Here, we compare the currently available aptamers for breast cancer biomarkers and their respective biomarkers, as well as highlight the electrochemical sensors that are in development.

Functional Implications of the Dynamic Regulation of EpCAM during Epithelial-to-Mesenchymal Transition

Epithelial cell adhesion molecule (EpCAM) is a transmembrane glycoprotein expressed in epithelial tissues. EpCAM forms intercellular, homophilic adhesions, modulates epithelial junctional protein complex formation, and promotes epithelial tissue homeostasis. EpCAM is a target of molecular therapies and plays a prominent role in tumor biology. In this review, we focus on the dynamic regulation of EpCAM expression during epithelial-to-mesenchymal transition (EMT) and the functional implications of EpCAM expression on the regulation of EMT. EpCAM is frequently and highly expressed in epithelial cancers, while silenced in mesenchymal cancers. During EMT, EpCAM expression is downregulated by extracellular signal-regulated kinases (ERK) and EMT transcription factors, as well as by regulated intramembrane proteolysis (RIP). The functional impact of EpCAM expression on tumor biology is frequently dependent on the cancer type and predominant oncogenic signaling pathways, suggesting that the role of EpCAM in tumor biology and EMT is multifunctional. Membrane EpCAM is cleaved in cancers and its intracellular domain (EpICD) is transported into the nucleus and binds β-catenin, FHL2, and LEF1. This stimulates gene transcription that promotes growth, cancer stem cell properties, and EMT. EpCAM is also regulated by epidermal growth factor receptor (EGFR) signaling and the EpCAM ectoderm (EpEX) is an EGFR ligand that affects EMT. EpCAM is expressed on circulating tumor and cancer stem cells undergoing EMT and modulates metastases and cancer treatment responses. Future research exploring EpCAM’s role in EMT may reveal additional therapeutic opportunities.

Increased expression of epithelial cell adhesion molecule and its possible role in epithelial-mesenchymal transition in endometriosis

AIM

To study the involvement and interrelationship of epithelial cell adhesion molecule (EpCAM) and epithelial-mesenchymal transition (EMT) in endometriosis.

METHODS

Samples from 114 patients undergoing endometrial biopsy or operation for endometriosis and 23 premenopausal women undergoing endometrial biopsy for non-endometriotic benign disease. Immunohistochemistry was used to detect expression level of EpCAM, E-cadherin and N-cadherin in endometrium from patients with (n = 24) and without endometriosis (n = 23), and in lesions from bowel (n = 46), peritoneal (n = 20) and ovarian (n = 24) endometriosis.

RESULTS

There was no significant difference in the expression level of EpCAM, E-cadherin and N-cadherin, respectively, between endometrium from women with and without endometriosis (P > 0.05). There was also no significant difference in the expression level of EpCAM, E-cadherin and N-cadherin, respectively, among lesions from the bowel, peritoneal and ovarian endometriosis (P > 0.05). We found that the immunoreactivity of endometriotic epithelial cells to EpCAM and N-cadherin was significantly higher than that of eutopic endometrium, but decreased to E-cadherin (P < 0.05). According to the expression level of EpCAM, the expression level of E-Cadherin was significantly lower in endometriotic lesions with EpCAM expression above the mean level compared with that of endometriotic lesions with EpCAM expression below mean level, while the expression level of N-cadherin was contrary (P < 0.001). EpCAM staining level was negatively correlated with E-cadherin but positively correlated with N-cadherin (P < 0.001).

CONCLUSIONS

These data suggest that overexpression of EpCAM, accompanied by an EMT, might be involved in endometriosis. EMT may be induced by the overexpression of EpCAM, thus promoting the development of endometriosis, which needs future studies to confirm for the pathogenesis of endometriosis.

Biologically driven cut-off definition of lymphocyte ratios in metastatic breast cancer and association with exosomal subpopulations and prognosis

High neutrophil to lymphocyte ratio (NLR) and monocyte to lymphocyte ratio (MLR) are respectively associated with systemic inflammation and immune suppression and have been associated with a poor outcome. Plasmatic exosomes are extracellular vesicles involved in the intercellular communication system that can exert an immunosuppressive function. Aim of this study was to investigate the interplay between the immune system and circulating exosomes in metastatic breast cancer (MBC). A threshold capable to classify patients according to MLR, NLR and PLR, was computed through a receiving operator curve analysis after propensity score matching with a series of female blood donors. Exosomes were isolated from plasma by ExoQuick solution and characterized by flow-cytometry. NLR, MLR, PLR and exosomal subpopulations potentially involved in the pre-metastatic niche were significantly different in MBC patients with respect to controls. MLR was significantly associated with number of sites at the onset of metastatic disease, while high levels of MLR and NLR were found to be associated with poor prognosis. Furthermore, exosomal subpopulations varied according to NLR, MLR, PLR and both were associated with different breast cancer subtypes and sites of distant involvement. This study highlights the nuanced role of immunity in MBC spread, progression and outcome. Moreover, they suggest potential interaction mechanisms between immunity, MBC and the metastatic niche.

Post-mortem tissue donation programs as platforms to accelerate cancer research

Given recent advances in the treatment of cancer, patients are surviving longer but frequently develop treatment-resistant and inoperable metastases. Biomedical research has advanced to the stage where in-depth study of these lesions is feasible, with the goal of further refining our understanding of metastatic dissemination, therapeutic resistance and inoperable tumors. However, there is a lack of tissue specimens derived from multiple metastatic sites within the same patient that would permit the study of these processes. Furthermore, patients with rapidly progressing or metastatic disease are rarely candidates for surgery, making those most in need of innovation and discovery extremely difficult to study. For this reason, post-mortem tissue donation programs are an approach that is quickly gaining traction in the cancer research community. Herein, we discuss what post-mortem tissue donation entails, attitudes towards these procedures, and highlight important studies already utilizing these resources. In addition, we propose future directions for use of this tissue that can directly improve clinical management of advanced cancer patients.

Synthesis of saporin-antibody conjugates for targeting EpCAM positive tumour cells

Epithelial cell adhesion molecule (EpCAM) is a transmembrane glycoprotein involved in cell proliferation and differentiation. Ribosomal inactivating proteins derived from plants specifically target ribosomes and irreversibly inhibit protein synthesis. EpCAM antibody and saporin were conjugated using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride/N-hydroxysuccinimide chemistry. The mass of the conjugates were characterised using matrix-assisted laser desorption ionisation (MALDI). The saporin-EpCAM (SAP-EpAB) conjugates were tested in-vitro against MCF-7 (breast cancer cells), WERI-Rb1 (retinoblastoma) cells. The flow cytometry and fluorescence microscopy were performed to show the binding efficiency of SAP-EpAB conjugate. Whole transcriptome changes of sap-conjugate treated cells were studied using affymetrix microarrays. MALDI-TOF analysis and polyacrylamide gel electrophoresis confirmed the conjugation of SAP with EpCAM antibody. Flow cytometry and fluorescent microscopy analysis revealed the binding of SAP-EpAB conjugates to the MCF-7, WERI-Rb1 cells. Apoptosis assay by annexin-V has shown an increased apoptotic and necrotic population in conjugate treated cells. MTT assay confirmed the tumour cell death and had shown the IC₅₀ value of 0.8 µg for conjugate in MCF-7 (breast cancer cells), and 1 µg for WERI-Rb1 (retinoblastoma) cells. The microarray analysis revealed downregulation of the tumourigenic genes and upregulation of pro-apoptotic genes leading to apoptosis of tumour cells.

A meta-analysis and The Cancer Genome Atlas data of prostate cancer risk and prognosis using epithelial cell adhesion molecule (EpCAM) expression

BACKGROUND

Epithelial cell adhesion molecule (EpCAM) expression has been reported in many types of cancer, including prostate cancer (PCa). However, the role of EpCAM expression remains inconsistent. We conducted a meta-analysis to assess the clinicopathological and prognostic significance of EpCAM expression in PCa.

METHODS

Publications were searched online using electronic databases. The available data were obtained from The Cancer Genome Atlas (TCGA). The odds ratios (ORs) or hazard ratios (HRs) with their 95% confidence intervals (CIs) were calculated.

RESULTS

We identified seven studies in which immunohistochemistry was used and that included 871 prostatic tissue samples. EpCAM expression was significantly higher in PCa samples than in benign and normal tissue samples (OR = 77.93, P = 0.002; OR = 161.61, P <  0.001; respectively). No correlation of EpCAM overexpression with pT stage and lymph node metastasis was observed; however, EpCAM overexpression showed a significant correlation with Gleason score (OR = 0.48, P = 0.012) and bone metastasis (OR = 145.80, P <  0.001). Furthermore, TCGA data showed that EpCAM overexpression was not closely correlated with age, pT stage, lymph node metastasis, number of lymph node, prostate-specific antigen level, Gleason score, biochemical recurrence, and overall survival. Based on multivariate Cox proportional-hazards regression analysis, a significant correlation was observed between EpCAM overexpression and 5-year worse biochemical recurrence free-survival.

CONCLUSIONS

EpCAM overexpression may be correlated with the development of bone metastasis and worse biochemical recurrence free-survival of PCa. Further studies are needed to verify these findings.

Epithelial cell adhesion molecule and epithelial-mesenchymal transition are associated with vasculogenic mimicry, poor prognosis, and metastasis of triple negative breast cancer

Triple-negative breast cancer (TNBC) is associated with epithelial-mesenchymal transition (EMT) and the phenotype of breast cancer stem cells (CSCs). Vasculogenic mimicry (VM) is a novel pattern of tumor blood supply and associated with aggression and metastasis of TNBC. Previous studies have shown that both CSCs and EMT are associated with VM, although the underlying mechanism is yet unclear. The present study aimed to analyze the immunohistochemical (IHC) expression of CSC marker, epithelial cell adhesion molecule (EpCAM), EMT-related markers, including transcription factors (TFs) (Slug, Twist1, and ZEB1), and EMT markers (E-cadherin and vimentin) in 137 TNBC. The expression of these markers was correlated to the clinicopathological features and VM channels of the tumors, including patient overall survival (OS) and disease-free survival (DFS). Furthermore, the expression of EpCAM and EMT-related markers showed a positive correlation with distant metastasis and lymph node metastasis (P < 0.05). A significant association was noted between VM and histological grade (P = 0.007). Moreover, VM showed a significant positive correlation with EpCAM, EMT-associated TFs, and VE-cadherin expression in TNBC. Furthermore, binary logistic analysis showed that VM expression was significantly correlated with lymph node metastasis and distant metastasis (P < 0.05). In survival analysis, the overexpression of EpCAM and ZEB1 predicted a poor prognosis with respect to OS and DFS. In addition, the presence of VM was significantly associated with poor OS and DFS. Multivariate Cox regression analysis revealed that VM expression is an independent prognostic factor for TNBC patients. In summary, VM was confirmed as a potential biomarker for TNBC associated with poor clinical outcomes and tumor metastasis. This study also suggested that EpCAM protein might be involved in VM formation by EMT in TNBC.

EpCAM Immunotherapy versus Specific Targeted Delivery of Drugs

The epithelial cell adhesion molecule (EpCAM), or CD326, was one of the first cancer associated biomarkers to be discovered. In the last forty years, this biomarker has been investigated for use in personalized cancer therapy, with the first monoclonal antibody, edrecolomab, being trialled in humans more than thirty years ago. Since then, several other monoclonal antibodies have been raised to EpCAM and tested in clinical trials. However, while monoclonal antibody therapy has been investigated against EpCAM for almost 40 years as primary or adjuvant therapy, it has not shown as much promise as initially heralded. In this review, we look at the reasons why and consider alternative targeting options, such as aptamers, to turn this almost ubiquitously expressed epithelial cancer biomarker into a viable target for future personalized therapy.

Ultrasensitive Quantitation of Plasma Membrane Proteins via isRTA

Quantitation of plasma membrane proteins (PMPs) is fundamental and frequently performed daily in the lab. However, challenged by the inherent/interacting heterostructures and complex surroundings of the PMPs in lipid membrane, quantitative techniques for PMP often require complex treatments (e.g., labeling, isolation, purification, and determination), and the sensitivity is usually not satisfactory. To address this problem, we have proposed a novel method that enables quantitation of PMPs with extremely high sensitivity, in an easier-to-manipulate and more streamlined way. This method is based on the design of an in situ rolling cycling replication-templated amplification strategy (isRTA). In fact, two rounds of DNA cascade isothermal amplifications have been conducted. The first round of amplification can provide templates for the second round of amplification; thus, significant enhancement of quantitative signals can be achieved. In this way, PMPs are quantified with ultrahigh sensitivity; as few as 25 copies of PMPs can be detected per cell. Moreover, the advantages of isRTA have been demonstrated by simultaneous identification of several PMP biomarkers (MUC1, EpCAM, and HER2) that are expressed over a wide distribution range on breast cancer cells. The precise typing of breast cancer cell subsets is thus possible because of the "quantitative-to-qualitative" strategy. Therefore, the unprecedented sensitivity and high usability of the isRTA method may present significant prospects for delving into membrane proteins and their related biofunctions in many research fields.

Aptamer-mediated survivin RNAi enables 5-fluorouracil to eliminate colorectal cancer stem cells

The development of chemoresistance and inability in elimination of cancer stem cells are among the key limitations of cancer chemotherapy. Novel molecular therapeutic strategies able to overcome such limitations are urgently needed for future effective management of cancer. In this report, we show that EpCAM-aptamer-guided survivin RNAi effectively downregulated survivin both in colorectal cancer cells in vitro and in a mouse xenograft model for colorectal cancer. When combined with the conventional chemotherapeutic agents, the aptamer-guided survivin RNAi was able to enhance the sensitivity towards 5-FU or oxaliplatin in colorectal cancer stem cells, increase apoptosis, inhibit tumour growth and improve the overall survival of mice bearing xenograft colorectal cancer. Our results indicate that survivin is one of the key players responsible for the innate chemoresistance of colorectal cancer stem cells. Thus, aptamer-mediated targeting of survivin in cancer stem cells in combination with chemotherapeutic drugs constitutes a new avenue to improve treatment outcome in oncologic clinics.

Immunocytochemical stem cell markers can predict clinical stage of breast cancer

We present a computational-statistical algorithm that, from data on the staining degree of immunocytochemical markers: i) evaluates the ability of the considered immuno-panel in predicting the breast cancer stage; ii) makes the accurate identification of breast cancer stage possible; iii) provides the best stage prognosis compatible with the considered sample; and iv) does so through the use of the minimum number of markers minimizing time and resource costs. After running the algorithm on two data sets [triple-negative breast cancer, (TNBC), and estrogen receptor-negative breast cancer, (ERNBC)], we conclude that EpCAM and β1 integrin are enough to accurately predict TNBC stage, being ALDH1, CD24, CD61, and CK5 the necessary markers to exactly predict ERNBC stage.

Clinical application of a microfluidic chip for immunocapture and quantification of circulating exosomes to assist breast cancer diagnosis and molecular classification

Increasing attention has been attracted by exosomes in blood-based diagnosis because cancer cells release more exosomes in serum than normal cells and these exosomes overexpress a certain number of cancer-related biomarkers. However, capture and biomarker analysis of exosomes for clinical application are technically challenging. In this study, we developed a microfluidic chip for immunocapture and quantification of circulating exosomes from small sample volume and applied this device in clinical study. Circulating EpCAM-positive exosomes were measured in 6 cases breast cancer patients and 3 healthy controls to assist diagnosis. A significant increase in the EpCAM-positive exosome level in these patients was detected, compared to healthy controls. Furthermore, we quantified circulating HER2-positive exosomes in 19 cases of breast cancer patients for molecular classification. We demonstrated that the exosomal HER2 expression levels were almost consistent with that in tumor tissues assessed by immunohistochemical staining. The microfluidic chip might provide a new platform to assist breast cancer diagnosis and molecular classification.

Subcellular differential expression of Ep-ICD in oral dysplasia and cancer is associated with disease progression and prognosis

Background

Identification of patients with oral dysplasia at high risk of cancer development and oral squamous cell carcinoma (OSCC) at increased risk of disease recurrence will enable rigorous personalized treatment. Regulated intramembranous proteolysis of Epithelial cell adhesion molecule (EpCAM) resulting in release of its intracellular domain Ep-ICD into cytoplasm and nucleus triggers oncogenic signaling. We analyzed the expression of Ep-ICD in oral dysplasia and cancer and determined its clinical significance in disease progression and prognosis.

Methods

In a retrospective study, immunohistochemical analysis of nuclear and cytoplasmic Ep-ICD and EpEx (extracellular domain of EpCAM), was carried out in 115 OSCC, 97 oral dysplasia and 105 normal oral tissues, correlated with clinicopathological parameters and disease outcome over 60 months for oral dysplasia and OSCC patients. Disease-free survival (DFS) was determined by Kaplan-Meier method and multivariate Cox regression analysis.

Results

In comparison with normal oral tissues, significant increase in nuclear Ep-ICD and membrane EpEx was observed in dysplasia, and OSCC (p = 0.013 and < 0.001 respectively). Oral dysplasia patients with increased overall Ep-ICD developed cancer in short time period (mean = 47 months; p = 0.044). OSCC patients with increased nuclear Ep-ICD and membrane EpEx had significantly reduced mean DFS of 33.7 months (p = 0.018).

Conclusions

Our study provided clinical evidence for Ep-ICD as a predictor of cancer development in patients with oral dysplasia and recurrence in OSCC patients, suggesting its potential utility in enhanced management of those patients detected to have increased risk of progression to cancer and recurrence in OSCC patients.

Epithelial cell adhesion molecule in human hepatocellular carcinoma cell lines: a target of chemoresistence

Background

The low survival rate of hepatocellular carcinoma (HCC) is partly attributable to its resistance to existing chemotherapeutic agents. Until now, there have been limited chemotherapeutic agents for liver cancer. Epithelial cell adhesion molecule (EpCAM) has been found to be over-expressed during stages of carcinogenesis and has been associated with poor overall survival in many cancers. The aim of this study was to evaluate EpCAM expression in HCC and evaluate the effects of EpCAM to established chemotherapy.

Methods

Three human hepatocellular carcinoma cell lines—HepG2, Hep3B and HuH-7—were pre- and post-treated with doxorubicin, 5-fluorouracil (5-FU) and cisplatin. Cell viability and EpCAM protein expression were measured by MTT assay and Western Blotting respectively. EpCAM positive cells were analyzed by flow cytometry. To evaluate the effects of doxorubicin efficacy on EpCAM positive cells, a small interfering RNA (siRNA) specific to EpCAM was transfected into the cells and treated with doxorubicin. Results: EpCAM was significantly down-regulated by doxorubicin treatment in all three HCC cell lines (P <0.05 or 0.01). EpCAM expression was down-regulated by the 5-FU and cisplatin in HepG2 cells, however the EpCAM expression was up-regulated by 5-FU and cisplatin in Hep3B cell line. EpCAM expression was down-regulated by 5-FU, and up-regulated by cisplatin in Huh-7 cell line. Flow cytometry assay showed doxorubicin exposure decreased EpCAM positive cell quantities in three HCC cell lines. EpCAM siRNA knock-down attenuated cell mortality after doxorubicin exposure.

Conclusion

All of these findings demonstrate that EpCAM is one of targets of chemoresistence.

Mechanisms involved in breast cancer liver metastasis

Liver metastasis is a frequent occurrence in patients with breast cancer; however, the available treatments are limited and ineffective. While liver-specific homing of breast cancer cells is an important feature of metastasis, the formation of liver metastases is not random. Indeed, breast cancer cell factors contribute to the liver microenvironment. Major breakthroughs have been achieved recently in understanding breast cancer liver metastasis (BCLM). The process of liver metastasis consists of multiple steps and involves various factors from breast cancer cells and the liver microenvironment. A further understanding of the roles of breast cancer cells and the liver microenvironment is crucial to guide future work in clinical treatments. In this review we discuss the contribution of breast cancer cells and the liver microenvironment to liver metastasis, with the aim to improve therapeutic efficacy for patients with BCLM.

Specific Recognition of Breast Cancer Cells In Vitro Using Near Infrared-Emitting Long-Persistence Luminescent Zn3Ga2Ge2O10:Cr3+ Nanoprobes

In this paper, near-infrared emitting long-persistence luminescent Zn₃Ga₂Ge₂O₁₀:Cr³⁺ (ZGG) nanoparticles with diameters of 30-100 nm and bright luminescence were prepared by a sol-gel synthesis method. After the surface amination, the nanoparticles were further bioconjugated with breast cancer-specific monoclonal antibody (anti-EpCAM) to form ZGG-EpCAM nanoprobes which can specifically target breast cancer cell lines (MCF7) in vitro. The results of in vitro images show that the luminescence signals from the cells treated with ZGG-EpCAM nanoprobes are stronger than those from cells treated with ZGG-unconjugated antibody, indicating that the prepared ZGG-EpCAM nanoprobes possessed excellent specific recognition capability. Furthermore, due to their long afterglow properties, the imaging could persist more than 1 h. Therefore, these nanoprobes could not only provide a high specificity detection method for cancer cells but also realize the long-time monitoring. Developed near-infrared emitting long-persistence luminescent nanoprobes will be expected to find new perspectives for cell therapy research and diagnosis applications.

Nuclear Ep-ICD accumulation predicts aggressive clinical course in early stage breast cancer patients

Background

Regulated intramembrane proteolysis of Epithelial cell adhesion molecule (EpCAM) results in release of its intracellular domain (Ep-ICD) which triggers oncogenic signalling. The clinical significance of Ep-ICD in breast cancer remains to be determined. Herein, we examined the expression of nuclear and cytoplasmic Ep-ICD, and membranous extracellular domain of EpCAM (EpEx) in breast cancer patients, to determine its potential utility in predicting aggressive clinical course of the disease.

Methods

In this retrospective study, 266 breast cancers and 45 normal breast tissues were immunohistochemically analyzed to determine the expression patterns of nuclear and cytoplasmic Ep-ICD and membranous EpEx and correlated with clinicopathological parameters and follow up. Disease-free survival was determined by Kaplan-Meier method and multivariate Cox regression analysis.

Results

Nuclear Ep-ICD was more frequently expressed in breast cancers compared to normal tissues. Significant association was observed between increased nuclear Ep-ICD expression and reduced disease-free survival in patients with ductal carcinoma in situ (DCIS) and invasive ductal carcinoma (IDC) (p < 0.001). Nuclear Ep-ICD was positive in all the 13 DCIS and 25 IDC patients who had reduced disease-free survival, while none of the nuclear Ep-ICD negative DCIS or IDC patients had recurrence during the follow up period. Notably, majority of IDC patients who had recurrence had early stage tumors. Multivariate Cox regression analysis identified nuclear Ep-ICD as the most significant predictive factor for reduced disease-free survival in IDC patients (p = 0.011, Hazard ratio = 80.18).

Conclusion

Patients with nuclear Ep-ICD positive breast cancers had poor prognosis. The high recurrence of disease in nuclear Ep-ICD positive patients, especially those with early tumor stage suggests that nuclear Ep-ICD accumulation holds the promise of identifying early stage patients with aggressive disease who are likely to be in need of more rigorous post-operative surveillance and/or treatment.

Tumor margin detection using quantitative NIRF molecular imaging targeting EpCAM validated by far red gene reporter iRFP

PURPOSE

Wide-field surgical excision reduces the chance of residual disease, but can also lead to disfigurement and devastating morbidities when resection is close to critical structures. We hypothesize that near-infrared fluorescence (NIRF) imaging can enable accurate detection of tumor margins for image-guided resection.

EXPERIMENTAL DESIGN

An orthotopic model of human prostate cancer (PCa) was used to assess primary tumor margins using a NIRF-labeled antibody against epithelial cell adhesion molecule (EpCAM). PCa cells stably expressing far red fluorescent gene reporter, iRFP, enabled colocalization with NIRF signals for direct assessment of tumor margins.

RESULTS

Using receiver operating characteristic analysis, far red fluorescence was validated against standard pathology of primary and metastatic lesions with >96 % accuracy. Primary tumor margins were more accurately detected by quantitative NIRF imaging using the EpCAM-targeting antibody as compared to a NIRF-labeled isotype control antibody.

CONCLUSIONS

NIRF molecular imaging may enable real-time and accurate assessment of tumor margins.

Clinicopathologic implications of EpCAM and Sox2 expression in breast cancer

BACKGROUND

The purpose of this study was to investigate the clinicopathologic significance of EpCAM and Sox2 expression in breast cancer and to study their correlation during breast cancer progression.

PATIENTS AND METHODS

EpCAm and Sox2 expression were assessed using immunohistochemistry in ductal carcinoma insitu (DCIS), invasive breast cancer (IBC) and matched lymph node metastasis (LNM), if present.

RESULTS

EpCAM overexpression was found in 63.2% of DCIS, 72.2% of IBC and 74.4% of LNM. In IBC cases, EpCAM overexpression was associated with high grade (P < .001), large tumor size (P = .051), poor Nottingham Prognostic Index (NPI) (P = .006), histological tumor types (P = .044) and the triple negative phenotype (P = .008). LNM frequently reflected the expression phenotype of the matched primary tumors with no significant differences between LNM and their primary tumors (P = .564). Sox2 expression was detected in 47.4%, 33.3% and 54.7% of DCIS, IBC and LNM respectively. In DCIS group, Sox2 expression was significantly associated with comedo type (P = .037), negative ER (P = .012) and PR (P = .037) and the triple negative phenotype (P = .006). In IBC cases, Sox2 expression showed significant associations with high grade (P = .045), nodal spread (P = .037), poor NPI (P = .018) and the triple negative phenotype (P < .001). LNM showed significantly higher Sox2 expression rates than primary tumors (P < .001). Significant positive associations between EpCAM overexpression and Sox2 positivity in DCIS (P = .027), IBC (P = .001) and LNM (P < .001) were found.

CONCLUSION

This study emphasized the potential role of EpCAM and Sox2 in breast carcinogenesis and revealed their involvement during breast cancer progression and LN metastases.

Capture of viable circulating tumor cells in the liver of colorectal cancer patients

BACKGROUND

The incidence and number of circulating tumor cells (CTCs) in the peripheral blood of colorectal cancer patients are lower than in other cancer types, which may point to a particular biology of colorectal cancer affecting CTC detection.

METHODS

We detected CTCs in the peripheral and mesenteric blood of colorectal cancer patients by use of 2 independent technologies on the basis of different biological properties of colon cancer cells. Seventy-five patients diagnosed with localized (M0, n = 60) and metastatic (M1, n = 15) colorectal cancer were included. Peripheral and mesenteric blood samples were collected before tumor resection. We performed CTC enumeration with an EpCAM-independent enrichment method followed by the Epispot assay that detected only viable CK19-releasing CTCs. In parallel, we used the FDA-cleared EpCAM-dependent CellSearch® as the reference method.

RESULTS

The enumeration of CK19-releasing cells by the CK19-Epispot assay revealed viable CTCs in 27 of 41 (65.9%) and 41 of 74 (55.4%) (P = 0.04) patients in mesenteric and peripheral blood, respectively, whereas CellSearch detected CTCs in 19 of 34 (55.9%) and 20 of 69 (29.0%) (P = 0.0046) patients. In mesenteric blood, medians of 4 (range 0-247) and 2.7 CTCs (range 0-286) were found with Epispot and CellSearch (P = 0.2), respectively, whereas in peripheral blood, Epispot and CellSearch detected a median of 1.2 (range 0-92) and 0 CTCs (range 0-147) (P = 0.002).

CONCLUSIONS

A considerable portion of viable CTCs detectable by the Epispot assay are trapped in the liver as the first filter organ in CRC patients.

Inhibition of established micrometastases by targeted drug delivery via cell surface-associated GRP78

PURPOSE

The major cause of morbidity in breast cancer is development of metastatic disease, for which few effective therapies exist. Because tumor cell dissemination is often an early event in breast cancer progression and can occur before diagnosis, new therapies need to focus on targeting established metastatic disease in secondary organs. We report an effective therapy based on targeting cell surface-localized glucose-regulated protein 78 (GRP78). GRP78 is expressed normally in the endoplasmic reticulum, but many tumors and disseminated tumor cells are subjected to environmental stresses and exhibit elevated levels of GRP78, some of which are localized at the plasma membrane.

EXPERIMENTAL DESIGN AND RESULTS

Here, we show that matched primary tumors and metastases from patients who died from advanced breast cancer also express high levels of GRP78. We used a peptidomimetic targeting strategy that uses a known GRP78-binding peptide fused to a proapoptotic moiety [designated bone metastasis targeting peptide 78 (BMTP78)] and show that it can selectively kill breast cancer cells that express surface-localized GRP78. Furthermore, in preclinical metastasis models, we show that administration of BMTP78 can inhibit primary tumor growth as well as prolong overall survival by reducing the extent of outgrowth of established lung and bone micrometastases.

CONCLUSIONS

The data presented here provide strong evidence that it is possible to induce cell death in established micrometastases by peptide-mediated targeting of cell surface-localized GRP in advanced breast cancers. The significance to patients with advanced breast cancer of a therapy that can reduce established metastatic disease should not be underestimated.

The use of sensitive chemical antibodies for diagnosis: detection of low levels of EpCAM in breast cancer

EpCAM is expressed at low levels in a variety of normal human epithelial tissues, but is overexpressed in 70–90% of carcinomas. From a clinico-pathological point of view, this has both prognostic and therapeutic significance. EpCAM was first suggested as a therapeutic target for the treatment of epithelial cancers in the 1990s. However, following several immunotherapy trials, the results have been mixed. It has been suggested that this is due, at least in part, to an unknown level of EpCAM expression in the tumors being targeted. Thus, selection of patients who would benefit from EpCAM immunotherapy by determining EpCAM status in the tumor biopsies is currently undergoing vigorous evaluation. However, current EpCAM antibodies are not robust enough to be able to detect EpCAM expression in all pathological tissues. Here we report a newly developed EpCAM RNA aptamer, also known as a chemical antibody, which is not only specific but also more sensitive than current antibodies for the detection of EpCAM in formalin-fixed paraffin-embedded primary breast cancers. This new aptamer, together with our previously described aptamer, showed no non-specific staining or cross-reactivity with tissues that do not express EpCAM. They were able to reliably detect target proteins in breast cancer xenograft where an anti-EpCAM antibody (323/A3) showed limited or no reactivity. Our results demonstrated a more robust detection of EpCAM using RNA aptamers over antibodies in clinical samples with chromogenic staining. This shows the potential of aptamers in the future of histopathological diagnosis and as a tool to guide targeted immunotherapy.

GATA3 expression in breast carcinoma: utility in triple-negative, sarcomatoid, and metastatic carcinomas

GATA3 plays an integral role in breast luminal cell differentiation and is implicated in breast cancer progression. GATA3 immunohistochemistry is a useful marker of breast cancer; however, its use in specific subtypes is unclear. Here, we evaluate GATA3 expression in 86 invasive ductal carcinomas including triple-negative, Her-2, and luminal subtypes, in addition to 13 metaplastic carcinomas and in 34 fibroepithelial neoplasms. In addition, we report GATA3 expression in matched primary and metastatic breast carcinomas in 30 patients with known estrogen receptor (ER), progesterone receptor (PR), and Her-2 status, including 5 with ER and/or PR loss from primary to metastasis. Tissue microarrays containing 5 to 10 cores per tumor were stained for GATA3, scored as follows: 0 (0-5%), 1+ (6%-25%), 2+ (26%-50%), 3+ (51%-75%), and 4+ (>75%). GATA3 labeling was seen in 67% (66/99) of primary ductal carcinomas including 43% of triple-negative and 54% of metaplastic carcinomas. In contrast, stromal GATA3 labeling was seen in only 1 fibroepithelial neoplasm. GATA3 labeling was seen in 90% (27/30) of primary breast carcinomas in the paired cohort, including 67% of triple-negative carcinomas. GATA3 labeling was overwhelmingly maintained in paired metastases. Notably, GATA3 was maintained in all "luminal loss" metastases, which showed ER and/or PR loss. In conclusion, GATA3 expression is maintained between matched primary and metastatic carcinomas including ER-negative cases. GATA3 can be particularly useful as a marker for metastatic breast carcinoma, especially triple-negative and metaplastic carcinomas, which lack specific markers of mammary origin. Finally, GATA3 labeling may help distinguish metaplastic carcinoma from malignant phyllodes tumors.

Detection of disseminated tumor cells in the bone marrow of breast cancer patients using multiplex gene expression measurements identifies new therapeutic targets in patients at high risk for the development of metastatic disease

Disseminated tumor cells (DTCs) detected in the bone marrow (BM) of breast cancer patients identify women at high risk of recurrence. DTCs are traditionally detected by immunocytochemical staining for cytokeratins or single gene expression measurements, which limit both specificity and sensitivity. We evaluated the Nanostring nCounter™ platform for multi-marker, gene expression-based detection and classification of DTCs in the BM of breast cancer patients. Candidate genes exhibiting tumor cell-specific expression were identified from microarray datasets and validated by qRT-PCR analysis in non-malignant human BM and identical samples spiked with predefined numbers of molecularly diverse breast tumor cell lines. Thirty-eight validated transcripts were designed for the nCounter™ platform and a subset of these transcripts was technically validated against qRT-PCR measurements using identical spiked BM controls. Bilateral iliac crest BM aspirates were collected and analyzed from twenty breast cancer patients, prior to neoadjuvant therapy, using the full 38-gene nCounter™ code set. Tumor cell-specific gene expression by nCounter™ was detected with a sensitivity of one cancer cell per 1 × 10(6) nucleated BM cells after optimization. Measurements were quantitative, log linear over a 20-fold range, and correlated with qRT-PCR measurements. Using the nCounter™ 38-gene panel, 6 of 8 patients (75 %) who developed metastatic disease had detectable expression of at least one transcript. Notably, three of these patients had detectable expression of ERBB2 in their BM, despite the fact that their corresponding primary tumors were HER2/ERBB2 negative and therefore did not receive trastuzumab therapy. Four of these patients also expressed the PTCH1 receptor, a newly recognized therapeutic target based on hedgehog signaling pathway inhibition. The presumptive detection and classification of DTCs in the BM of breast cancer patients, based on sensitive and quantitative multi-marker detection of gene expression using the nCounter™ platform, provide an opportunity to both predict early distant recurrence and, more importantly, identify opportunities for preventing the spread of disease based on the expression of unique, therapeutically actionable gene targets. This study demonstrates the application of a new technology for multiplexed gene expression-based detection of DTCs in the BM of breast cancer patients and identifies at least two therapeutically targetable genes that are frequently expressed in the BM of patients who develop metastatic disease.

Phenotype-dependent effects of EpCAM expression on growth and invasion of human breast cancer cell lines

Background

The epithelial cell adhesion molecule (EpCAM) has been shown to be overexpressed in breast cancer and stem cells and has emerged as an attractive target for immunotherapy of breast cancer patients. This study analyzes the effects of EpCAM on breast cancer cell lines with epithelial or mesenchymal phenotype.

Methods

For this purpose, shRNA-mediated knockdown of EpCAM gene expression was performed in EpCAM^high breast cancer cell lines with epithelial phenotype (MCF-7, T47D and SkBR3). Moreover, EpCAM^low breast carcinoma cell lines with mesenchymal phenotype (MDA-MB-231, Hs578t) and inducible overexpression of EpCAM were used to study effects on proliferation, migration and in vivo growth.

Results

In comparison to non-specific silencing controls (n/s-crtl) knockdown of EpCAM (E#2) in EpCAM^high cell lines resulted in reduced cell proliferation under serum-reduced culture conditions. Moreover, DNA synthesis under 3D culture conditions in collagen was significantly reduced. Xenografts of MCF-7 and T47D cells with knockdown of EpCAM formed smaller tumors that were less invasive. EpCAM^low cell lines with tetracycline-inducible overexpression of EpCAM showed no increased cell proliferation or migration under serum-reduced growth conditions. MDA-MB-231 xenografts with EpCAM overexpression showed reduced invasion into host tissue and more infiltrates of chicken granulocytes.

Conclusions

The role of EpCAM in breast cancer strongly depends on the epithelial or mesenchymal phenotype of tumor cells. Cancer cells with epithelial phenotype need EpCAM as a growth- and invasion-promoting factor, whereas tumor cells with a mesenchymal phenotype are independent of EpCAM in invasion processes and tumor progression. These findings might have clinical implications for EpCAM-based targeting strategies in patients with invasive breast cancer.

An Ep-ICD based index is a marker of aggressiveness and poor prognosis in thyroid carcinoma

Background

Nuclear accumulation of the intracellular domain of epithelial cell adhesion molecule (Ep-ICD) in tumor cells was demonstrated to predict poor prognosis in thyroid carcinoma patients in our earlier study. Here, we investigated the clinical significance of Ep-ICD subcellular localization index (ESLI) in distinguishing aggressive papillary thyroid carcinoma (PTC) from non-aggressive cases.

Methods

Using domain specific antibodies against the intracellular (Ep-ICD) and extracellular (EpEx) domains of epithelial cell adhesion molecule, 200 archived tissues from a new cohort of patients with benign thyroid disease as well as malignant aggressive and non aggressive PTC were analyzed by immunohistochemistry (IHC). ESLI was defined as sum of the IHC scores for accumulation of nuclear and cytoplasmic Ep-ICD and loss of membranous EpEx; ESLI = [Ep-ICD_nuc + Ep-ICD_cyt + loss of membranous EpEx].

Results

For the benign thyroid tissues, non-aggressive PTC and aggressive PTC, the mean ESLI scores were 4.5, 6.7 and 11 respectively. Immunofluorescence double staining confirmed increased nuclear Ep-ICD accumulation and decreased membrane EpEx expression in aggressive PTC. Receiver-operating characteristic (ROC) curve analysis showed an area under the curve (AUC) of 0.841, 70.2% sensitivity and 83.9% specificity for nuclear Ep-ICD for differentiating aggressive PTC from non-aggressive PTC. ESLI distinguished aggressive PTC from non-aggressive cases with improved AUC of 0.924, 88.4% sensitivity and 85.5% specificity. Our study confirms nuclear accumulation of Ep-ICD and loss of membranous EpEx occurs in aggressive PTC underscoring the potential of Ep-ICD and ESLI to serve as diagnostic markers for aggressive PTC. Kaplan Meier survival analysis revealed significantly reduced disease free survival (DFS) for ESLI positive (cutoff >10) PTC (p<0.05), mean DFS = 133 months as compared to 210 months for patients who did not show positive ESLI.

Conclusion

ESLI scoring improves the identification of aggressive PTC and thereby may serve as a useful index for defining aggressiveness and poor prognosis among PTC patients.

Expression and role of epithelial cell adhesion molecule in dysplastic nodule and hepatocellular carcinoma

Epithelial cell adhesion molecule (EpCAM) has been proposed as a marker for cancer stem cells in human hepatocellular carcinoma (HCC). However, the function and clinical significance of EpCAM in HCC is largely unknown. We examined EpCAM expression and localization in 28 dysplastic nodules (DNs) and their corresponding cirrhotic nodules, 79 HCC tissue sections and 132 HCC tissue microarray cores by immunohistochemistry and determined the relationship to clinicopathologic findings. We also examined the role of EpCAM in HCC using synthetic small interfering RNA to silence EpCAM gene expression in Huh-7 cells. EpCAM expression was very rare in DNs but dominantly appeared in a distinctly nodular type of small HCC. Expression of EpCAM was observed in 39% (31/79) of HCC tissue sections and in 34.1% (45/132) of tissue microarray sections. EpCAM expression in HCC was significantly associated with high tumor grade and serum α-fetoprotein level. Silencing EpCAM gene expression significantly decreased the proliferative activity and invasiveness of HCC cells. EpCAM expression was an independent prognostic factor for survival in patients with T1 HCC. The data indicate that EpCAM expression occurs at distinct nodular stage of HCC and could play an important role in HCC progression.

Phase IB study of the EpCAM antibody adecatumumab combined with docetaxel in patients with EpCAM-positive relapsed or refractory advanced-stage breast cancer

BACKGROUND

Targeted therapy options in HER2-negative breast cancer are limited. This open-label, multicenter phase IB dose-escalation trial was conducted to determine safety, tolerability, and antitumor activity of a combination of docetaxel (Taxotere) and increasing doses of adecatumumab, a human IgG1 antibody targeting epithelial cell adhesion molecule (EpCAM), in EpCAM-positive relapsed or primary refractory advanced-stage breast cancer.

PATIENTS AND METHODS

Patients pretreated with up to four prior chemotherapy regimens received increasing adecatumumab doses either every 3 weeks (q3w) or weekly (qw) combined with docetaxel (100 mg/m(2) q3w). Primary end points were safety and tolerability. Antitumor activity was evaluated according to RECIST. Clinical benefit was defined as complete or partial response or stable disease for ≥24 weeks.

RESULTS

Thirty-one evaluable patients were treated. Most adverse events were mild to moderate in severity. Neutropenia, leukocytopenia, lymphopenia, and diarrhea (dose-limiting) were the most frequent toxic effects. Maximum tolerated doses of adecatumumab given in combination with docetaxel were 550 mg/m(2) q3w and 360 mg/m(2) qw. Clinical benefit was observed in 44% of patients treated with q3w adecatumumab and docetaxel, increasing to 63% in patients with high EpCAM-expressing tumors.

CONCLUSION

Combination therapy of adecatumumab and docetaxel is safe, feasible, and potentially active in heavily pretreated advanced-stage breast cancer.

Silencing of Irf7 pathways in breast cancer cells promotes bone metastasis through immune escape

Breast cancer metastasis is a key determinant of long-term patient survival. By comparing the transcriptomes of primary and metastatic tumor cells in a mouse model of spontaneous bone metastasis, we found that a substantial number of genes suppressed in bone metastases are targets of the interferon regulatory factor Irf7. Restoration of Irf7 in tumor cells or administration of interferon led to reduced bone metastases and prolonged survival time. In mice deficient in the interferon (IFN) receptor or in natural killer (NK) and CD8(+) T cell responses, metastasis was accelerated, indicating that Irf7-driven suppression of metastasis was reliant on IFN signaling to host immune cells. We confirmed the clinical relevance of these findings in over 800 patients in which high expression of Irf7-regulated genes in primary tumors was associated with prolonged bone metastasis-free survival. This gene signature may identify patients that could benefit from IFN-based therapies. Thus, we have identified an innate immune pathway intrinsic to breast cancer cells, the suppression of which restricts immunosurveillance to enable metastasis.

Androgen receptor expression is usually maintained in initial surgically resected breast cancer metastases but is often lost in end-stage metastases found at autopsy

Androgen receptor (AR) is expressed in approximately 70% of primary breast carcinomas (PBCs) and is a promising therapeutic target for metastatic breast carcinoma (MBC). Here, we examine AR expression in a population of initial surgically resected metastases and a separate cohort of end-stage metastases harvested at autopsy compared with their matched PBCs. Tissue microarrays of matched PBC and MBC were labeled by immunohistochemistry for AR, estrogen receptor (ER), progesterone receptor (PR), and Her2 and classified into the following previously described categories: luminal (ER/PR+/Her2-), triple negative (ER/PR/Her2-), Her2 (ER/PR-/Her2+), and luminal loss (ER/PR loss from primary to metastasis). In the cohort of surgically resected metastases (n = 16), AR was expressed in 12 of 16 PBC and maintained in 11 of 12 corresponding MBCs. Of these, 36% showed stronger AR labeling in the metastases and none showed a decrease. In the cohort of metastases harvested at autopsy (n = 16), AR was expressed in 11 of 16 primary carcinomas and maintained in only 5 of 11 corresponding metastases. Of these, none showed increased AR and 80% showed decreased AR labeling. AR expression is overwhelmingly concordant between matched PBC and MBC at initial presentation. These findings validate AR as a therapeutic target in MBC and suggest that AR may need to be reevaluated in metastases even if the primary is negative. However, similar to ER/PR, AR expression is often decreased with a trend toward complete loss in end-stage metastases, suggesting a shift of AR expression between initial and end-stage metastases. This suggests an opportunity for targeted antiandrogen therapy at an earlier stage of disease progression.

Stem cell-related markers in primary breast cancers and associated metastatic lesions

It has been reported previously that: (1) normal-breast epithelial cells that are CD24-/44+ express higher levels of stem/progenitor cell-associated genes; (2) cancer cells that have undergone epithelial to mesenchymal transition display CD24-/44+ cell-surface expression, a marker for breast cancer stem cells; (3) loss of E-cadherin is a preliminary step in epithelial to mesenchymal transition; and (4) vimentin is a marker of mesenchymal phenotype. We hypothesized that stem cell subpopulations would be more frequent in metastatic than in primary tumors. Therefore we assessed by immunohistochemical analysis, tissue microarrays containing tissue from primary and associated metastatic breast cancers for expression of CD24, CD44, E-cadherin and vimentin to evaluate candidate cancer-initiating cell populations in breast cancer subtypes and metastatic lesions. The occurrence of CD24-/44+ and CD24+/44- cells did not differ in primary vs matched lymph node or distant and locoregional metastatic lesions; E-cadherin expression was decreased in primary vs lymph node metastases (P=0.018) but not decreased in distant and locoregional metastases relative to primary tumor, whereas vimentin, was more frequently expressed in lymph node and distant and locoregional metastases (P=0.013, P=0.004) than in matched primary cancers. Thus, the frequency of CD24-/44+ cells does not differ in metastases relative to the primary breast cancer but differs by tumor stage and subtype.