Role Of Epithelial Cell Adhesion Molecule Research Articles

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.

Epithelial cell adhesion molecule promotes breast cancer resistance protein-mediated multidrug resistance in breast cancer by inducing partial epithelial-mesenchymal transition.

Overexpression of breast cancer resistance protein (BCRP) plays a crucial role in the acquired multidrug resistance (MDR) in breast cancer. The elucidation of molecular events that confer BCRP-mediated MDR is of major therapeutic importance in breast cancer. Epithelial cell adhesion molecule (EpCAM) has been implicated in tumor progression and drug resistance in various types of cancers, including breast cancer. However, the role of EpCAM in BCRP-mediated MDR in breast cancer remains unknown. In the present study, we revealed that EpCAM expression was upregulated in BCRP-overexpressing breast cancer MCF-7/MX cells, and EpCAM knockdown using siRNA reduced BCRP expression and increased the sensitivity of MCF-7/MX cells to mitoxantrone (MX). The epithelial-mesenchymal transition (EMT) promoted BCRP-mediated MDR in breast cancer cells, and EpCAM knockdown partially suppressed EMT progression in MCF-7/MX cells. In addition, Wnt/β-catenin signaling was activated in MCF-7/MX cells, and the inhibition of this signaling attenuated EpCAM and BCRP expression and partially reversed EMT. Together, this study illustrates that EpCAM upregulation by Wnt/β-catenin signaling induces partial EMT to promote BCRP-mediated MDR resistance in breast cancer cells. EpCAM may be a potential therapeutic target for overcoming BCRP-mediated resistance in human breast cancer.

Epithelial cell adhesion molecule (EpCAM) is involved in prostate cancer chemotherapy/radiotherapy response in vivo

BackgroundDevelopment of chemo−/radioresistance is a major challenge for the current prostate cancer (CaP) therapy. We have previously demonstrated that epithelial cell adhesion molecule (EpCAM) is associated with CaP growth and therapeutic resistance in vitro, however, the role of EpCAM in CaP in vivo is not fully elucidated. Here, we aimed to investigate how expression of EpCAM is involved in CaP growth and chemo−/radiotherapy response in NOD/SCID mouse models in vivo and to validate its role as a therapeutic target for CaP therapy.MethodsEpCAM was knocked down in PC-3 CaP cell line using short hairpin RNA (shRNA). The effect of EpCAM-knockdown (KD) on tumour growth, chemo−/radiotherapy response and animal survival was evaluated on subcutaneous (s.c) and orthotopic mouse models.ResultsWe found that KD of EpCAM significantly inhibited tumour growth, increased xenograft sensitivity to chemotherapy/radiotherapy, and prolonged the survival of tumour-bearing mice. In addition, we demonstrated that KD of EpCAM is associated with downregulation of the PI3K/Akt/mTOR pathway.ConclusionsIn conclusion, our data confirms that CaP growth and chemo−/radioresistance in vivo is associated with over-expression of EpCAM, which serves both a functional biomarker and promising therapeutic target.

Concise Review: Aggressive Colorectal Cancer: Role of Epithelial Cell Adhesion Molecule in Cancer Stem Cells and Epithelial-to-Mesenchymal Transition.

Colorectal cancer (CRC) is one of the most common malignancies worldwide. In spite of various attempts to ameliorate outcome by escalating treatment, significant improvement is lacking particularly in the adjuvant setting. It has been proposed that cancer stem cells (CSCs) and the epithelial‐to‐mesenchymal transition (EMT) are at least partially responsible for therapy resistance in CRC. The epithelial cell adhesion molecule (EpCAM) was one of the first CSC antigens to be described. Furthermore, an EpCAM‐specific antibody (edrecolomab) has the merit of having launched the era of monoclonal antibody treatment in oncology in the 1990s. However, despite great initial enthusiasm, monoclonal antibody treatment has not proven successful in the adjuvant treatment of CRC patients. In the meantime, new insights into the function of EpCAM in CRC have emerged and new drugs targeting various epitopes have been developed. In this review article, we provide an update on the role of EpCAM in CSCs and EMT, and emphasize the potential predictive selection criteria for novel treatment strategies and refined clinical trial design. stem cells translational medicine 2018;7:495–501

Abstract 2833: Epithelial cell adhesion molecule (EpCAM) is associated with prostate cancer progression and chemo-/radio-resistance in vitro and in vivo

Abstract Aims: Prostate cancer (CaP) is the most common cancer in males in Australia which caused more than 3000 deaths in 2015. EpCAM is a transmembrane protein that is expressed at low levels in a variety of human epithelial tissues, but overexpressed in most solid tumors. Our previous study indicated that EpCAM was strongly expressed in metastatic CaP cell lines, primary human CaP tissues and lymph node metastasis and is a biomarker involved in CaP progression, and chemo-/radio-resistance. However, the role of EpCAM in CaP progression and therapeutic resistance is still uncertain. The aim of this study was to investigate the role of EpCAM in CaP progression and chemo-/radio-resistance as well as underlying mechanisms in vitro and in vivo. Methods: EpCAM gene was knocked down (KD) in PC-3, DU145 and LNCaP CaP cell lines using shRNA. Proliferation assay, colony formation assay, docetaxel (DTX) and radiation dose-response assay were carried out to evaluate the effect of KD of EpCAM on proliferation and therapeutic response of CaP cells in vitro. Subcutaneous (s.c) and orthotopic CaP animal models were established using PC-3-EpCAM-KD and PC-3-EpCAM-scramble (scr) control cells in NOD/SCID mice, to assess the effect of EpCAM on CaP tumourigenecity, chemotherapy (DTX) and radiation response. Signal transduction proteins in PI3K/Akt/mTOR signaling pathway, as well as proliferation, apoptotic and radiation response markers were evaluated by immunohistochemistry in xenografts. Results: KD of EpCAM reduced CaP proliferative potential and enhanced DTX and radiation sensitivity in three CaP cell lines. Both s.c and orthotopic EpCAM-KD xenografts displayed suppressed tumor growth and increased DTX and radiation responsiveness compared to EpCAM-scr control xenografts in NOD/SCID mice. Marked down-regulation of PI3K/Akt/mTOR pathway proteins (p-Akt and p-mTOR) and proliferation marker (Ki-67) and significant up-regulation of apoptotic (Caspase-3) and radiation (γ-H2AX) responses to chemo-/radio-therapies were found in EpCAM-KD xenografts, compared with control xenografts. In addition, Kaplan-Meier curve analysis demonstrated that KD of EpCAM improved median survival (MS) of tumor-bearing mice by 21.5 days compared with the control group (HR=26.94, CI95% 4.317-168.1, p=0.0004) and that KD of EpCAM improved MS of tumor-bearing mice which received docetaxel (50mg/kg, single dose, i.p.) by 11 days (HR=20.95, CI95% 3.599-121.9, p=0.0007), and radiotherapy (2Gy/day for 4 days) by 12 days (HR=11.00, CI95% 2.11-57.36, p=0.0044) compared with the control group, respectively. Conclusions: EpCAM plays an important role in CaP progression and chemo-/radio-resistance via PI3K/Akt/mTOR signaling pathway in vitro and in vivo and it is a promising therapeutic target for the treatment of CaP. EpCAM targeted therapy combined with chemo-/radio-therapy could be a novel modality for treatment-resistant CaP. Citation Format: Jie Ni, Paul Cozzi, Julia Beretov, Junli Deng, Joseph Bucci, Peter Graham, Yong Li. Epithelial cell adhesion molecule (EpCAM) is associated with prostate cancer progression and chemo-/radio-resistance in vitro and in vivo [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2833. doi:10.1158/1538-7445.AM2017-2833

A double-negative feedback loop between EpCAM and ERK contributes to the regulation of epithelial-mesenchymal transition in cancer.

Epithelial-mesenchymal transition (EMT) is an important biological process that has been implicated in cancer metastasis. Epithelial cell adhesion molecule (EpCAM) is expressed at the basolateral membrane of most normal epithelial cells but is overexpressed in many epithelial cancers. In our studies on the role of EpCAM in cancer biology, we observed that EpCAM expression is decreased in mesenchymal-like primary cancer specimens in vivo and following induction of EMT in cancer cell lines in vitro. Extracellular signal-related kinase (ERK) is a key regulator of EMT. We observed that EpCAM expression is decreased with activation of the ERK pathway in primary cancer specimens in vivo and in cancer cell lines in vitro. In experimental models, growth factor stimulation and/or oncogene-induced ERK2 activation suppressed EpCAM expression, whereas genetic or pharmacological inhibition of the ERK pathway restored EpCAM expression. In detailed studies of the EpCAM promoter region, we observed that ERK2 suppresses EpCAM transcription directly by binding to a consensus ERK2-binding site in the EpCAM promoter and indirectly through activation of EMT-associated transcription factors SNAI1, SNAI2, TWIST1 and ZEB1, which bind to E-box sites in the EpCAM promoter. Surprisingly, EpCAM appears to modulate ERK activity. Using multiple cell lines, we demonstrated that specific ablation of EpCAM resulted in increased ERK pathway activity and SNAI2 expression, migration and invasion, whereas forced expression of EpCAM resulted in decreased ERK pathway activity and SNAI2 expression, migration and invasion. These observations provide important insights into the regulation of EpCAM expression during EMT, demonstrate an unexpected role for EpCAM in the regulation of ERK and define a novel double-negative feedback loop between EpCAM and ERK that contributes to the regulation of EMT. These studies have important translational implications as both EpCAM and ERK are currently being targeted in human clinical trials.

The role of EpCAM in physiology and pathology of the epithelium.

Epithelial Cell Adhesion Molecule (EpCAM) has been discovered as one of the first tumor-specific antigens overexpressed in epithelial cancer. The present review focuses on the role of EpCAM in physiology and homeostasis of epithelia. Recent research pointed to a close interaction of EpCAM with other cell-cell contact molecules like E-cadherin and claudins and an intimate crosstalk with Wnt and TGF-beta signaling in the regulation of cell growth. Moreover, EpCAM has been shown to modulate trans-epithelial migration processes of white blood cells. Mutations of the EpCAM gene lead to disturbances of epithelial homeostasis and cellular differentiation from the stem cell compartment. In the intestinal tract EpCAM mutations contribute to congenital tufting enteropathy. Regarding tumorigenesis EpCAM can act as an oncogene still depending on additional driver mutations and epithelial phenotype of tumor cells. Tumor cells display increased EpCAM expression that often correlates with the loss of strict basolateral localization. Many tumors show enhanced regulated intramembrane proteolysis (RIP) of EpCAM and loose EpCAM expression under conditions of epithelial to mesenchymal transition. The resulting extracellular EpEX and intracellular EpICD fragments mediate proliferative signals to the cell. Resulting fragments can be validated either by sensitive enzyme-linked immune-sandwich assays (EpEX) or by immunohistochemistry (EpICD). The present review gives an overview on the detection of EpCAM fragments as predictive markers for disease progression and survival of cancer patients.

Knockdown of EpCAM enhances the chemosensitivity of breast cancer cells to 5-fluorouracil by downregulating the antiapoptotic factor Bcl-2.

Resistance to fluoropyrimidine-based chemotherapy is the main reason for the failure of cancer treatment, and drug resistance is associated with an inability of tumor cells to undergo apoptosis in response to treatment. Alterations in the expression of epithelial cell adhesion molecule (EpCAM) affect the sensitivity or resistance of tumor cells to anticancer treatment and the activity of intracellular signaling pathways. However, the role of EpCAM in the induction of apoptosis in breast cancer cells remains unclear. Here, we investigated the effect of EpCAM gene knockdown on chemosensitivity to 5-fluorouracil (5-FU) in MCF-7 cells and explored the underlying mechanisms. Our results showed that knockdown of EpCAM promoted apoptosis, inhibited cell proliferation and caused cell-cycle arrest. EpCAM knockdown enhanced the cytotoxic effect of 5-FU, promoting apoptosis by downregulating the expression of the anti-apoptotic protein Bcl-2 and upregulating the expression of the pro-apoptotic proteins Bax, and caspase3 via the ERK1/2 and JNK MAPK signaling pathways in MCF-7 cells. These results indicate that knockdown of EpCAM may have a tumor suppressor effect and suggest EpCAM as a potential target for the treatment of breast cancer.

Epithelial cell-adhesion molecule-directed trifunctional antibody immunotherapy for symptom management of advanced ovarian cancer

Despite advances in cytotoxic chemotherapy and surgical cytoreduction, disease recurrence continues to be a troubling problem in patients with advanced-stage epithelial ovarian cancer (EOC). Malignant ascites affects approximately 10% of patients with recurrent EOC and is associated with troublesome symptoms, including abdominal pressure, distension, dyspnea, pelvic pain, and bowel/bladder dysfunction. To date, no effective therapy has been identified for the treatment of malignant ascites in patients with recurrent, advanced-stage ovarian cancer. Recently, immune modulation has gained attention as a novel approach to anti-cancer therapy. This review explores the role of epithelial cell-adhesion molecule (EpCAM)-directed immunotherapy, with a specific focus on the mechanism of action of the trifunctional antibody catumaxomab (anti-EpCAM × anti-CD3). In addition, clinical trials exploring the use of catumaxomab in the treatment of malignant ascites in patients with ovarian cancer are reviewed.

EpCAM Expression Is an Indicator of Increased Incidence of Relapse in p53-Positive Breast Cancer

Originally identified as Trop1, epithelial cell adhesion molecule (EpCAM) is a transmembrane glycoprotein that received great attention because of its putative involvement in metastatic spread of several solid tumors including breast cancer. Experimental evidence indicated that EpCAM is a key transcriptional target of p53 tumor suppressor, due to the presence of specific p53 response elements within EPCAM gene promoter. Aim of present study was to investigate the joined prognostic significance of p53 and EpCAM in a cases series of 640 breast cancers with long-term follow-up. In addition, considering the role of EpCAM in modulating cell-cell interaction by decreasing the cytoskeleton-anchored fraction of E-cadherin, when feasible, we evaluated also E-cadherin expression. Results indicated that EpCAM overexpression was associated with a high incidence of relapse and that, when in association with p53 status, EpCAM was able to identify, within p53-positive cases, those with the highest incidence of relapse. Conversely, E-cadherin overexpression was associated with a low incidence of relapse. Overall, these findings are of particular clinical relevance taking into account the biological link between p53 activity and EPCAM gene expression and the functional relationship between EpCAM and E-cadherin in mediating cell-to-cell adhesion.

Abstract 1982: Turmeric oil inhibits hepatocellular carcinoma through abolishing EpCAM expression

Abstract Background: In previous study, we found that turmeric oil, a volatile oil from turmeric, can prevent hepatocellular carcinoma (HCC) in an orthotopic HCC mouse model. Epithelial cell adhesion molecule (EpCAM), a marker of cancer stem cells (CSC), is correlated with HCC initiation, progression, and prognosis. Our resent data showed that turmeric oil can decrease EpCAM expression in esophageal cancer and HCC cell lines. Since the role of EpCAM in HCC carcinogenesis is becoming clarified, it is likely that turmeric oil prevents HCC through EpCAM signaling. Aim: To investigate the mechanism of turmeric oil for HCC prevention. Method: EpCAM expression in the specimens from HCC patients (n=25) was evaluated by immunohistochemical staining. Red fluorescent protein (RFP)-labeled H4IIE cells were inoculated into liver lobe of ACI rats. The rat HCC tumor tissues from RFP-H4IIE cell inoculation were evaluated for the subpopulation cells, which co-expressed RFP and EpCAM. The HCC rats by H4IIE cell inoculation were treated with turmeric oil (100mg/kg, i.p, every 2 days) for 2 weeks. The H4IIE cells treated with turmeric oil as well as with EpCAM siRNA, and then inoculated at 106 into the right flank of nude BALB/c mice for 1 week. Three HCC cell lines from human (HepG-2), mouse (hepal-6), and rat (H4IIE) cells, were treated with turmeric oil to evaluate the cell viability EpCAM expression, and β-catenin in vitro. Results: In human samples, a strong EpCAM expression was found HCC tissues, while EpCAM was barely detected in the healthy controls. In HCC animal models, RFP+ EpCAM+ cells were detected in the formed tumor tissue and in circulation. The incidence of HCC by H4IIE cells inoculation was significantly decreased in rats treated with turmeric oil. Abolishing of EpCAM by turmeric oil caused the H4IIE cells unable to form tumor in nude mice. In cell culture study, turmeric oil significantly decreased EpCAM expression in all three HCC cell lines. Turmeric oil caused relocalization of β-catenin, a component in Wnt/β-catenin pathway, in nuclear and cytosol (Figure 1). Conclusion: 1) EpCAM-positive HCC cells contribute to HCC initiation in animal models; 2) The inhibition of HCC by turmeric oil is through decreasing EpCAM expression; 3). The regulation of EpCAM expression by turmeric oil is associated with Wnt/β-catenin pathway. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1982. doi:1538-7445.AM2012-1982

Impact of the EpCAM expression on biochemical recurrence-free survival in clinically localized prostate cancer

BackgroundThe epithelial cell adhesion molecule (EpCAM) is a transmembrane glycoprotein that was originally identified as a marker for carcinoma, attributable to its high expression on rapidly proliferating tumors of epithelial origin. The role of EpCAM is not limited to cell adhesion but includes diverse processes such as signaling, cell migration, proliferation, and differentiation. ObjectiveSeveral studies investigated EpCAM expression in prostate carcinoma but none of them confirmed its prognostic role. The aim of our study was to investigate EpCAM expression and its relationship with established prognostic features in prostate carcinoma. Materials and methodsThe study included a cohort of 102 patients treated with radical prostatectomy for clinically localized prostate carcinoma. Immunohistochemistry was performed to evaluate the EpCAM expression in prostate cancer and non-neoplastic prostate tissue. The percentage of positively stained carcinoma and benign glands was examined in the whole mount of the chosen slide. ResultsThe extent of EpCAM expression was significantly higher in malignant than in benign prostatic tissue (P < 0.001). EpCAM expression in prostate cancer was associated with established features indicative of worse prognosis, such as preoperative (P = 0.009) and postoperative (P = 0.004) Gleason score and follow-up time (P < 0.001). Patients with higher preoperative and postoperative Gleason score and short follow-up time had tumors with a significantly higher expression of EpCAM. Negative correlation of follow-up time and EpCAM expression indicated that tumors in patients with biochemical recurrence (BCR) harbored higher EpCAM expression. Moreover, expression of EpCAM was significantly higher in patients with BCR compared with patients without BCR (P < 0.001). Tumors in T3 stage of the disease showed significantly higher EpCAM expression compared with T2 tumors (P = 0.002). Univariate (P < 0.001) and multivariate (P < 0.001) analyses showed that EpCAM expression was a significant predictor of shorter biochemical recurrence free-survival. ConclusionOur results confirmed high level of EpCAM expression in prostate cancer and support its potential role in prostatic cancer progression. In addition, EpCAM could serve as an additional prognostic marker for the recognition of patients with an increased risk of disease recurrence that need introduction of secondary therapy.

Abstract 1657: A pivotal role for epithelial cell adhesion molecule (EpCAM) in survival of lung cancer cells

Abstract Introduction: Epithelial cell adhesion molecule (EpCAM) is overexpressed in a wide variety of human cancers, including lung cancer, and its contribution to increased proliferation through up-regulating cell cycle accelerators such as cyclin A/E is well demonstrated in breast and gastric cancers. Nevertheless, very little is known about its role in survival of cancer cells. In addition, functional role of EpCAM in the pathogenesis of lung cancer remains to be explored. Matrials and methods: 18 human non-small cell lung cancer cell lines and an immortalized normal human bronchial epithelial cell (HBEC4) lines were used. EpCAM expression was measured by quantitative real-time PCR (qRT-PCR) and FACS. RNA interference (RNAi)-mediated gene silencing for EpCAM was done in three non-small cell lung cancer cell and HBEC4 lines. Cell proliferation was measured by WST-1 and clonogenic growth was measured by liquid and soft agar colony formation assays. Apoptosis was evaluated by annexin V/7-AAD staining. FACS with PI staining was done to examine apoptosis and cell cycle. p27kip1 expression was evaluated by western blot analysis. In vitro invasion assay was done by using transwell chambers layered with matrigel and invading cells were stained and counted. Results: We analyzed the expression of EpCAM in a panel of lung cancer cell and HBEC4 lines and found that most of lung cancer cell lines expressed EpCAM. EpCAM knockdown suppressed proliferation and clonogenic growth of two EpCAM-expressing lung cancer cell lines in anchorage dependent and independent conditions. EpCAM knockdown suppressed invasiveness in a highly invasive line but not in a lowly invasive cell line. In addition, EpCAM knockdown induced massive apoptosis in both cell lines as well as another EpCAM-expressing lung cancer cell line but to a much lesser extent in HBEC4 line. EpCAM knockdown caused lung cancer cells to have increased responsiveness to contact inhibition in part through up-regulating p27kip1 cyclin dependent kinase inhibitor. Conclusion: These results demonstrate that EpCAM substantially contributes to the pathogenesis of lung cancer, especially in its survival, and the development of EpCAM-targeted therapy for lung cancer may have promise. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1657. doi:10.1158/1538-7445.AM2011-1657