Extracellular domain of EpCAM enhances tumor progression through EGFR signaling in colon cancer cells

A "One-Step" Strategy for the Global Characterization of Core-Fucosylated Glycoproteome

Core fucosylation, a special type of N-linked glycosylation, is important in tumor proliferation, invasion, metastatic potential, and therapy resistance. However, the core-fucosylated glycoproteome has not been extensively profiled due to the low abundance and poor ionization efficiency of glycosylated peptides. Here, a "one-step" strategy has been described for protein core-fucosylation characterization in biological samples. Core-fucosylated peptides can be selectively labeled with a glycosylated probe, which is linked with a temperature-sensitive poly(N-isopropylacrylamide) (PNIPAM) polymer, by mutant endoglycosidase (EndoF3-D165A). The labeled probe can be further removed by wild-type endoglycosidase (EndoF3) in a traceless manner for mass spectrometry (MS) analysis. The feasibility and effectiveness of the "one-step" strategy are evaluated in bovine serum albumin (BSA) spiked with standard core-fucosylated peptides, H1299, and Jurkat cell lines. The "one-step" strategy is then employed to characterize core-fucosylated sites in human lung adenocarcinoma, resulting in the identification of 2494 core-fucosylated sites distributed on 1176 glycoproteins. Further data analysis reveals that 196 core-fucosylated sites are significantly upregulated in tumors, which may serve as potential drug development targets or diagnostic biomarkers. Together, this "one-step" strategy has great potential for use in global and in-depth analysis of the core-fucosylated glycoproteome to promote its mechanism research.

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.

Progress of Clinical Studies Targeting Claudin18.2 for the Treatment of Gastric Cancer

Claudin18.2 is a tight junction protein, highly selective, generally expressed only in normal gastric mucosal epithelial cells, which can effectively maintain the polarity of epithelial and endothelial cells, thus effectively regulating the permeability and conductance of the paracellular pathway. Abnormal expression of Claudin18.2 can occur in various primary malignant tumors, especially gastrointestinal tumors, and even in metastatic foci. It regulates its expression by activating the aPKC/MAPK/AP-1 pathway, and therefore, the Claudin18.2 protein is a pan-cancer target expressed in primary and metastatic lesions in human cancer types. Zolbetuximab (IMAB362), an antibody specific for Claudin18.2, has been successfully tested in a phase III clinical trial, and the results of the study showed that combining Zolbetuximab with chemotherapy notably extends patients' survival and is expected to be a potential first-line treatment for patients with Claudin18.2(+)/HER-2(-) gastric cancer. Here, we systematically describe the biological properties and oncogenic effects of Claudin18.2, centering on its clinical-pathological aspects and the progress of drug studies in gastric cancer, which can help to further explore its clinical value.

Durvalumab with or without tremelimumab plus chemotherapy in HRR non-mutated, platinum-resistant ovarian cancer (KGOG 3045): A phase II umbrella trial

AIM

We investigated the efficacy and safety of durvalumab (D) with or without tremelimumab (T) in addition to single-agent chemotherapy (CT) in patients with platinum-resistant recurrent ovarian cancer (PROC) lacking homologous recombination repair (HRR) gene mutations.

PATIENTS AND METHODS

KGOG 3045 was an open-label, investigator-initiated phase II umbrella trial. Patients with PROC without HRR gene mutations who had received ≥2 prior lines of therapy were enrolled. Patients with high PD-L1 expression (TPS ≥25%) were assigned to arm A (D + CT), whereas those with low PD-L1 expression were assigned to arm B (D + T75 + CT). After completing arm B recruitment, patients were sequentially assigned to arms C (D + T300 + CT) and D (D + CT).

RESULTS

Overall, 58 patients were enrolled (5, 18, 17, and 18 patients in arms A, B, C, and D, respectively). The objective response rates were 20.0, 33.3, 29.4, and 22.2%, respectively. Grade 3-4 treatment-related adverse events were observed in 20.0, 66.7, 47.1, and 66.7 of patients, respectively, but were effectively managed. Multivariable analysis demonstrated that adding T to D + CT improved progression-free survival (adjusted HR, 0.435; 95% CI, 0.229-0.824; P = 0.011). Favorable response to chemoimmunotherapy was associated with MUC16 mutation (P = 0.0214), high EPCAM expression (P = 0.020), high matrix remodeling gene signature score (P = 0.017), and low FOXP3 expression (P = 0.047). Patients showing favorable responses to D + T + CT exhibited significantly higher EPCAM expression levels (P = 0.008) and matrix remodeling gene signature scores (P = 0.031) than those receiving D + CT.

CONCLUSIONS

Dual immunotherapy with chemotherapy showed acceptable response rates and tolerable safety in HRR non-mutated PROC, warranting continued clinical investigation.

Comprehensive analysis reveals dual biological function roles of EpCAM in kidney renal clear cell carcinoma

Background

Epithelial cell adhesion molecule (EpCAM), a well-established marker for circulating tumor cells, plays a crucial role in the complex process of cancer metastasis. The primary objective of this investigation is to study EpCAM expression in pan-cancer and elucidate its significance in the context of kidney renal clear cell carcinoma (KIRC).

Methods

Data obtained from the public database was harnessed for the comprehensive assessment of the EpCAM expression levels and prognostic and clinicopathological correlations in thirty-three types of cancer. EpCAM was validated in our own KIRC sequencing and immunohistochemical cohorts. Subsequently, an in-depth exploration was conducted to scrutinize the interrelationship between EpCAM and various facets, including immune cells, immune checkpoints, and chemotherapy drugs. We employed Cox regression analysis to identify prognostic immunomodulators associated with EpCAM, which were subsequently utilized in the development of a prognostic model. The model was validated in our own clinical cohort and public datasets, and compared with 137 published models. The role of EpCAM in KIRC was explored by biological function experiments in vitro.

Results

While EpCAM exhibited pronounced overexpression across a wide spectrum of cancer types, a notable reduction was observed in KIRC tissues. As grade increased, EpCAM expression decreased. EpCAM expression decreased in patients without metastasis. EpCAM mRNA and protein levels were used as independent, favorable prognostic factors in patients with KIRC in our own cohort. The expression of EpCAM exhibited strong associations with immune-related pathways, demonstrating an inverse correlation with the majority of immune cell types. Immune checkpoint inhibitors exert better therapeutic effects on patients with low EpCAM expression. In addition, EpCAM can be used as a drug resistance indicator and guide the clinical medication of patients with KIRC. A robust model, which had good predictive accuracy and applicability, showed significant superiority over other models. Importantly, EpCAM played the dual roles of promoting proliferation and resisting metastasis in KIRC.

Conclusion

In the context of KIRC, EpCAM assumes a surprising dual role, where it not only facilitates cell proliferation but also exerts resistance against the metastatic process. EpCAM serves as a standalone prognostic marker for patients with KIRC, and related models can also effectively predict prognosis. These discoveries offer novel perspectives on the functional significance of EpCAM in the context of KIRC.

Epithelial cell adhesion molecule (EpCAM) regulates HGFR signaling to promote colon cancer progression and metastasis

BACKGROUND

Epithelial cell adhesion molecule (EpCAM) is known to highly expression and promotes cancer progression in many cancer types, including colorectal cancer. While metastasis is one of the main causes of cancer treatment failure, the involvement of EpCAM signaling in metastatic processes is unclear. We propose the potential crosstalk of EpCAM signaling with the HGFR signaling in order to govern metastatic activity in colorectal cancer.

METHODS

Immunoprecipitation (IP), enzyme-linked immunosorbent assay (ELISA), and fluorescence resonance energy transfer (FRET) was conducted to explore the extracellular domain of EpCAM (EpEX) and HGFR interaction. Western blotting was taken to determine the expression of proteins in colorectal cancer (CRC) cell lines. The functions of EpEX in CRC were investigated by proliferation, migration, and invasion analysis. The combined therapy was validated via a tail vein injection method for the metastasis and orthotopic colon cancer models.

RESULTS

This study demonstrates that the EpEX binds to HGFR and induces downstream signaling in colon cancer cells. Moreover, EpEX and HGF cooperatively mediate HGFR signaling. Furthermore, EpEX enhances the epithelial-to-mesenchymal transition and metastatic potential of colon cancer cells by activating ERK and FAK-AKT signaling pathways, and it further stabilizes active β-catenin and Snail proteins by decreasing GSK3β activity. Finally, we show that the combined treatment of an anti-EpCAM neutralizing antibody (EpAb2-6) and an HGFR inhibitor (crizotinib) significantly inhibits tumor progression and prolongs survival in metastatic and orthotopic animal models of colon cancer.

CONCLUSION

Our findings illuminate the molecular mechanisms underlying EpCAM signaling promotion of colon cancer metastasis, further suggesting that the combination of EpAb2-6 and crizotinib may be an effective strategy for treating cancer patients with high EpCAM expression.

Oral administration of M13-loaded nanoliposomes is safe and effective to treat colitis-associated cancer in mice

OBJECTIVE

Colitis-associated cancer (CAC) treatment lacks effective small-molecule drugs and efficient targeted delivery systems. Here, we loaded M13 (an anti-cancer drug candidate) to colon-targeting ginger-derived nanoliposomes (NL) and investigated if orally administered M13-NL could enhance the anticancer effects of M13 in CAC mouse models.

METHODS

The biopharmaceutical properties of M13 were assessed by physicochemical characterizations. The in vitro immunotoxicity of M13 was assessed against PBMCs using FACS and the mutagenic potential of M13 was evaluated by the Ames assay. The in vitro efficacy of M13 was tested in 2D- and 3D-cultured cancerous intestinal cells. AOM/DSS-induced CAC mice were used to evaluate the therapeutic effects of free M13 or M13-NL on CAC in vivo.

RESULTS

M13 has beneficial physiochemical properties, including high stability, and no apparent immunotoxicity or mutagenic potential in vitro. M13 is effective against the growth of 2D- and 3D-cultured cancerous intestinal cells in vitro. The in vivo safety and efficacy of M13 were significantly improved by using NL for drug delivery (p < 0.001). Oral administration of M13-NL exhibited excellent therapeutic effects in AOM/DSS-induced CAC mice.

CONCLUSION

M13-NL is a promising oral drug formulation for CAC treatment.

EpEX, the soluble extracellular domain of EpCAM, resists cetuximab treatment of EGFR-high head and neck squamous cell carcinoma

OBJECTIVES

Cetuximab (Cmab) is a molecularly targeted monoclonal antibody drug for head and neck squamous cell carcinoma (HNSC), although cetuximab resistance is a serious challenge. Epithelial cell adhesion molecule (EpCAM) is an established marker for many epithelial tumors, while the soluble EpCAM extracellular domain (EpEX) functions as a ligand for epidermal growth factor receptor (EGFR). We investigated the expression of EpCAM in HNSC, its involvement in Cmab action, and the mechanism by which soluble EpEX activated EGFR and played key roles in Cmab resistance.

MATERIALS AND METHODS

We first examined EPCAM expression in HNSCs and its clinical significance by searching gene expression array databases. We then examined the effects of soluble EpEX and Cmab on intracellular signaling and Cmab efficacy in HNSC cell lines (HSC-3 and SAS).

RESULTS

EPCAM expression was found to be enhanced in HNSC tumor tissues compared to normal tissues, and the enhancement was correlated with stage progression and prognosis. Soluble EpEX activated the EGFR-ERK signaling pathway and nuclear translocation of EpCAM intracellular domains (EpICDs) in HNSC cells. EpEX resisted the antitumor effect of Cmab in an EGFR expression-dependent manner.

CONCLUSION

Soluble EpEX activates EGFR to increase Cmab resistance in HNSC cells. The EpEX-activated Cmab resistance in HNSC is potentially mediated by the EGFR-ERK signaling pathway and the EpCAM cleavage-induced nuclear translocation of EpICD. High expression and cleavage of EpCAM are potential biomarkers for predicting the clinical efficacy and resistance to Cmab.

EpCAM tumor specificity and proteoform patterns in urothelial cancer

BACKGROUND

The role of the epithelial cell adhesion molecule (EpCAM) in cancer is still unclear. EpCAM cleavage through regulated intramembrane proteolysis results in fragments which interact with both oncogenic and tumor suppressive pathways. Additionally, the EpCAM molecule itself is used as a descriptive therapeutic target in urothelial cancer (UC), while data on its actual tumor specificity remain limited.

METHODS

Samples from diagnostic formalin-fixed paraffin-embedded (FFPE) UC tissue and fresh-frozen UC cells were immunoblotted and used for qualitative characterization of five different EpCAM fragments. These expression patterns were quantified across a cohort of 76 samples with 52 UC and 24 normal urothelial samples. Cell viability effects of the extracellular EpEX fragment were assessed in the UC cell lines T24 and HT1376.

RESULTS

The proteolytic EpCAM fragments could be identified in clinical FFPE tissue specimens too. Neither overall nor fragment-specific EpCAM expression showed relevant tumor specificity. EpEX and its deglycosylated variant showed an inverse relationship across healthy and tumor tissue with a decrease of deglycosylated EpEX in tumors. However, extracellular EpEX did not show a relevant effect in vitro.

CONCLUSIONS

EpCAM should not be regarded as tumor-specific in UC without patient-specific predictive testing. EpCAM fragment patterns indicate cancer-specific changes and could be involved in its complex tumor-biological role.

Cell Therapy as Target Therapy against Colon Cancer Stem Cells

Cancer stem cells (CSCs) are a small subpopulation of cells within tumors with properties, such as self-renewal, differentiation, and tumorigenicity. CSCs have been proposed as a plausible therapeutic target as they are responsible for tumor recurrence, metastasis, and conventional therapy resistance. Selectively targeting CSCs is a promising strategy to eliminate the propagation of tumor cells and impair overall tumor development. Recent research shows that several immune cells play a crucial role in regulating tumor cell proliferation by regulating different CSC maintenance or proliferation pathways. There have been great advances in cellular immunotherapy using T cells, natural killer (NK) cells, macrophages, or stem cells for the selective targeting of tumor cells or CSCs in colorectal cancer (CRC). This review summarizes the CRC molecular profiles that may benefit from said therapy and the main vehicles used in cell therapy against CSCs. We also discuss the challenges, limitations, and advantages of combining conventional and/or current targeted treatments in the late stages of CRC.

Inferring spatial transcriptomics markers from whole slide images to characterize metastasis-related spatial heterogeneity of colorectal tumors: A pilot study

Over 150 000 Americans are diagnosed with colorectal cancer (CRC) every year, and annually over 50 000 individuals will die from CRC, necessitating improvements in screening, prognostication, disease management, and therapeutic options. Tumor metastasis is the primary factor related to the risk of recurrence and mortality. Yet, screening for nodal and distant metastasis is costly, and invasive and incomplete resection may hamper adequate assessment. Signatures of the tumor-immune microenvironment (TIME) at the primary site can provide valuable insights into the aggressiveness of the tumor and the effectiveness of various treatment options. Spatially resolved transcriptomics technologies offer an unprecedented characterization of TIME through high multiplexing, yet their scope is constrained by cost. Meanwhile, it has long been suspected that histological, cytological, and macroarchitectural tissue characteristics correlate well with molecular information (e.g., gene expression). Thus, a method for predicting transcriptomics data through inference of RNA patterns from whole slide images (WSI) is a key step in studying metastasis at scale. In this work, we collected tissue from 4 stage-III (pT3) matched colorectal cancer patients for spatial transcriptomics profiling. The Visium spatial transcriptomics (ST) assay was used to measure transcript abundance for 17 943 genes at up to 5000 55-micron (i.e., 1-10 cells) spots per patient sampled in a honeycomb pattern, co-registered with hematoxylin and eosin (H&E) stained WSI. The Visium ST assay can measure expression at these spots through tissue permeabilization of mRNAs, which are captured through spatially (i.e., x-y positional coordinates) barcoded, gene specific oligo probes. WSI subimages were extracted around each co-registered Visium spot and were used to predict the expression at these spots using machine learning models. We prototyped and compared several convolutional, transformer, and graph convolutional neural networks to predict spatial RNA patterns at the Visium spots under the hypothesis that the transformer- and graph-based approaches better capture relevant spatial tissue architecture. We further analyzed the model's ability to recapitulate spatial autocorrelation statistics using SPARK and SpatialDE. Overall, the results indicate that the transformer- and graph-based approaches were unable to outperform the convolutional neural network architecture, though they exhibited optimal performance for relevant disease-associated genes. Initial findings suggest that different neural networks that operate on different scales are relevant for capturing distinct disease pathways (e.g., epithelial to mesenchymal transition). We add further evidence that deep learning models can accurately predict gene expression in whole slide images and comment on understudied factors which may increase its external applicability (e.g., tissue context). Our preliminary work will motivate further investigation of inference for molecular patterns from whole slide images as metastasis predictors and in other applications.

Multi-Targeting Nano-Systems Targeting Heterogeneous Cancer Cells for Therapeutics and Biomarker Detection

Cancer heterogeneity plays a vital part in cancer resistance and metastasis. To provide a reliable approach to exert a therapy action and evaluate its efficiency in heterogeneous cancer cells, a multiple targeting delivery vector composed of histone encapsulating the therapeutic or diagnostic agent, hyaluronic acid targeting CD44 overexpressed in stem tumor cells, SYL3C aptamer targeting epithelial cell adhesion molecule (EpCAM) overexpressed in epithelial cancer cells, and CL4 aptamer targeting epidermal growth factor receptor (EGFR) overexpressed in mesenchymal cancer cells, is developed. The vector can efficiently target different cancer cells and circulating tumor cells (CTCs) in the peripheral blood of patients for mucin 1 (MUC1) knockout. Furthermore, the multiple targeting vector can be used to co-encapsulate three types of molecular beacons for probing various mRNA biomarkers at single-cell resolution after genome editing. This study provides an efficient approach for exerting therapeutic actions in heterogeneous cancer cells and assessing the therapeutic efficacy by detection of cancer biomarkers via liquid biopsy.

CAR T-cells for colorectal cancer immunotherapy: Ready to go?

Chimeric antigen receptor (CAR) T-cells represent a new genetically engineered cell-based immunotherapy tool against cancer. The use of CAR T-cells has revolutionized the therapeutic approach for hematological malignancies. Unfortunately, there is a long way to go before this treatment can be developed for solid tumors, including colorectal cancer. CAR T-cell therapy for colorectal cancer is still in its early stages, and clinical data are scarce. Major limitations of this therapy include high toxicity, relapses, and an impermeable tumor microenvironment for CAR T-cell therapy in colorectal cancer. In this review, we summarize current knowledge, highlight challenges, and discuss perspectives regarding CAR T-cell therapy in colorectal cancer.

Understanding the versatile roles and applications of EpCAM in cancers: from bench to bedside

Epithelial cell adhesion molecule (EpCAM) functions not only in physiological processes but also participates in the development and progression of cancer. In recent decades, extensive efforts have been made to decipher the role of EpCAM in cancers. Great advances have been achieved in elucidating its structure, molecular functions, pathophysiological mechanisms, and clinical applications. Beyond its well-recognized role as a biomarker of cancer stem cells (CSCs) or circulating tumor cells (CTCs), EpCAM exhibits novel and promising value in targeted therapy. At the same time, the roles of EpCAM in cancer progression are found to be highly context-dependent and even contradictory in some cases. The versatile functional modules of EpCAM and its communication with other signaling pathways complicate the study of this molecule. In this review, we start from the structure of EpCAM and focus on communication with other signaling pathways. The impacts on the biology of cancers and the up-to-date clinical applications of EpCAM are also introduced and summarized, aiming to shed light on the translational prospects of EpCAM.

T cell-inflamed gene expression profile is associated with favorable disease-specific survival in non-hypermutated microsatellite-stable colorectal cancer patients

BACKGROUND

The anti-tumor immune response plays a key role in colorectal cancer (CRC) progression and survival. The T cell-inflamed gene expression profile (GEP) is a biomarker predicting response to checkpoint inhibitor immunotherapy across immunogenic cancer types, but the prognostic value in CRC is unknown. We evaluated associations with disease-specific survival, somatic mutations, and examined its differentially expressed genes and pathways among 84 sporadic CRC patients from the Seattle Colon Cancer Family Registry.

METHODS

Gene expression profiling was performed using Nanostring's nCounter PanCancer IO 360 panel. Somatic mutations were identified by a targeted DNA sequencing panel.

RESULTS

The T cell-inflamed GEP was positively associated with tumor mutation burden and microsatellite instability high (MSI-H). Higher T cell-inflamed GEP had favorable CRC-specific survival (hazard ratio [HR] per standard deviation unit = 0.50, p = 0.004) regardless of hypermutation or MSI status. Analysis of recurrently mutated genes having at least 10 mutation carriers, suggested that the T cell-inflamed GEP is positively associated with RYR1, and negatively associated with APC. However, these associations were attenuated after adjusting for hypermutation or MSI status. We also found that expression of genes RPL23, EPCAM, AREG and ITGA6, and the Wnt signaling pathway was negatively associated with the T cell-inflamed GEP, which might indicate immune-inhibitory mechanisms.

CONCLUSIONS

Our results show that the T cell-inflamed GEP is a prognostic biomarker in non-hypermutated microsatellite-stable CRC. This also suggests that patient stratification for immunotherapy within this CRC subgroup should be explored further. Moreover, reported immune-inhibitory gene expression signals may suggest targets for therapeutic combination with immunotherapy.

Recent advances in CAR-T cells therapy for colorectal cancer

Colorectal cancer (CRC) is the third most common cancer, with a high mortality rate and a serious impact on people’s life and health. In recent years, adoptive chimeric antigen receptor T (CAR-T) cells therapy has shown well efficacy in the treatment of hematological malignancies, but there are still many problems and challenges in solid tumors such as CRC. For example, the tumor immunosuppressive microenvironment, the low targeting of CAR-T cells, the short time of CAR-T cells in vivo, and the limited proliferation capacity of CAR-T cells, CAR-T cells can not effectively infiltrate into the tumor and so on. New approaches have been proposed to address these challenges in CRC, and this review provides a comprehensive overview of the current state of CAR-T cells therapy in CRC.

A transcriptomic map of EGFR-induced epithelial-to-mesenchymal transition identifies prognostic and therapeutic targets for head and neck cancer

Background

Epidermal growth factor receptor (EGFR) is both a driver oncogene and a therapeutic target in advanced head and neck squamous cell carcinoma (HNSCC). However, response to EGFR treatment is inconsistent and lacks markers for treatment prediction. This study investigated EGFR-induced epithelial-to-mesenchymal transition (EMT) as a central parameter in tumor progression and identified novel prognostic and therapeutic targets, and a candidate predictive marker for EGFR therapy response.

Methods

Transcriptomic profiles were analyzed by RNA sequencing (RNA-seq) following EGFR-mediated EMT in responsive human HNSCC cell lines. Exclusive genes were extracted via differentially expressed genes (DEGs) and a risk score was determined through forward feature selection and Cox regression models in HNSCC cohorts. Functional characterization of selected prognostic genes was conducted in 2D and 3D cellular models, and findings were validated by immunohistochemistry in primary HNSCC.

Results

An EGFR-mediated EMT gene signature composed of n = 171 genes was identified in responsive cell lines and transferred to the TCGA-HNSCC cohort. A 5-gene risk score comprising DDIT4, FADD, ITGB4, NCEH1, and TIMP1 prognosticated overall survival (OS) in TCGA and was confirmed in independent HNSCC cohorts. The EGFR-mediated EMT signature was distinct from EMT hallmark and partial EMT (pEMT) meta-programs with a differing enrichment pattern in single malignant cells. Molecular characterization showed that ITGB4 was upregulated in primary tumors and metastases compared to normal mucosa and correlated with EGFR/MAPK activity in tumor bulk and single malignant cells. Preferential localization of ITGB4 together with its ligand laminin 5 at tumor-stroma interfaces correlated with increased tumor budding in primary HNSCC tissue sections. In vitro, ITGB4 knock-down reduced EGFR-mediated migration and invasion and ITGB4-antagonizing antibody ASC8 impaired 2D and 3D invasion. Furthermore, a logistic regression model defined ITGB4 as a predictive marker of progression-free survival in response to Cetuximab in recurrent metastatic HNSCC patients.

Conclusions

EGFR-mediated EMT conveyed through MAPK activation contributes to HNSCC progression upon induction of migration and invasion. A 5-gene risk score based on a novel EGFR-mediated EMT signature prognosticated survival of HNSCC patients and determined ITGB4 as potential therapeutic and predictive target in patients with strong EGFR-mediated EMT.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12943-022-01646-1.

Dynamic Expression of EpCAM in Primary and Metastatic Lung Cancer Is Controlled by Both Genetic and Epigenetic Mechanisms

Simple Summary

Epithelial cell adhesion molecule (EpCAM) is a tumor marker widely used in both basic studies and clinics. However, our study demonstrates that EpCAM expression is strongly upregulated by gene amplification and promoter hypomethylation in primary lung tumors, but severely downregulated by epigenetic repression (including promoter hypermethylation and histone deacetylation), tumor-associated macrophages (TAMs), and TAMs-derived TGFβ in metastatic lung tumors. DNMT inhibitor 5-aza-dC, HDAC inhibitor MS-275, and TGFβ neutralizing antibody are able to restore EpCAM expression in highly metastatic lung cancer cells. These findings disclose that multiple mechanisms contribute to the dynamic expression patterns of EpCAM in primary and metastatic lung tumors, redefining the application of EpCAM as a biomarker in tumor cell identification and isolation in specific cancers and clinical stages.

Abstract

Although great progress has been achieved in cancer treatment in the past decades, lung cancer remains the leading cause of cancer death, which is partially caused by the fact that most lung cancers are diagnosed at advanced stages. To improve the sensitivity and specificity of lung cancer diagnosis, the underlying mechanisms of current diagnosis methods are in urgent need to be explored. Herein, we find that the expression of EpCAM, the widely used molecular marker for tumor cell characterization and isolation, is strongly upregulated in primary lung tumors, which is caused by both gene amplification and promoter hypomethylation. In contrast, EpCAM expression is severely repressed in metastatic lung tumors, which can be reversed by epigenetic drugs, DNMT inhibitor 5-aza-dC and HDAC inhibitor MS-275. Moreover, tumor-associated macrophages (TAMs) impede EpCAM expression probably through TGFβ-induced EMT signaling. These findings unveil the dynamic expression patterns of EpCAM and differential roles of epigenetic modification in EpCAM expression in primary and metastatic lung tumors, providing novel insights into tumor cell isolation and lung cancer diagnosis.

Ret kinase-mediated mechanical induction of colon stem cells by tumor growth pressure stimulates cancer progression in vivo

How mechanical stress actively impacts the physiology and pathophysiology of cells and tissues is little investigated in vivo. The colon is constantly submitted to multi-frequency spontaneous pulsatile mechanical waves, which highest frequency functions, of 2 s period, remain poorly understood. Here we find in vivo that high frequency pulsatile mechanical stresses maintain the physiological level of mice colon stem cells (SC) through the mechanosensitive Ret kinase. When permanently stimulated by a magnetic mimicking-tumor growth analogue pressure, we find that SC levels pathologically increase and undergo mechanically induced hyperproliferation and tumorigenic transformation. To mimic the high frequency pulsatile mechanical waves, we used a generator of pulsed magnetic force stimulation in colonic tissues pre-magnetized with ultra-magnetic liposomes. We observed the pulsatile stresses using last generation ultra-wave dynamical high-resolution imaging. Finally, we find that the specific pharmacological inhibition of Ret mechanical activation induces the regression of spontaneous formation of SC, of CSC markers, and of spontaneous sporadic tumorigenesis in Apc mutated mice colons. Consistently, in human colon cancer tissues, Ret activation in epithelial cells increases with tumor grade, and partially decreases in leaking invasive carcinoma. High frequency pulsatile physiological mechanical stresses thus constitute a new niche that Ret-dependently fuels mice colon physiological SC level. This process is pathologically over-activated in the presence of permanent pressure due to the growth of tumors initiated by pre-existing genetic alteration, leading to mechanotransductive self-enhanced tumor progression in vivo, and repressed by pharmacological inhibition of Ret.

Ho-Bouldoires, Sollier, Zamfirov and Broders-Bondon et al. show that high frequency pulsatile mechanical stresses maintain the physiological level of mice colon stem cells through the mechanosensitive Ret kinase and that Ret activation is elevated in human colon cancer tissue. They go on to show that the maintenance of such stimulation in the form of tumour growth pressure results in mechanically-induced hyperproliferation and tumorigenic transformation of stem cells, which can be prevented by Ret kinase inhibition.

Autophagy-related signaling pathways in non-small cell lung cancer

Lung cancer is one of the most prevalent causes of morbidity and mortality in both men and women across the globe. The disease has a quiet phenotype at first, which leads to chronic tumor development. Non-small cell lung cancer (NSCLC) is the most common kind of lung cancer, accounting for 85 percent of all lung malignancies. Autophagy has been described as an intracellular "recycle bin" where damaged proteins and molecules are degraded. Autophagy regulation is mainly dependent on signaling pathways such as phosphoinositide 3-kinases (PI3K), AKT, and the mammalian target of rapamycin (mTOR). In the context of NSCLC, studies on these signaling pathways are inconsistent, but our literature review suggests that the inhibition of mTOR, PI3K/AKT, and epidermal growth factor receptor signaling pathways by different medications can active autophagy and inhibit NSCLC progression. In conclusion, signaling pathways related to autophagy are effective therapeutic approaches for the treatment of NSCLC.

Targeting Wnt Signaling in the Tumor Immune Microenvironment to Enhancing EpCAM CAR T-Cell therapy

Colorectal cancer (CRC) patients are still lacking viable treatments. Chimeric antigen receptor (CAR) T cells have shown promise in hematologic malignancies, but their efficacy in solid tumors has been limited due to the immunosuppressive tumor microenvironment. We found that cancer antigen- EpCAM expression increased in the metastatic stage compared with the primary stage in cancers and the activation of Wnt and TGFβ pathways was positively correlated with EpCAM expression in multiple cancers, including colorectal cancer. We constructed CAR T cells targeting EpCAM that successfully showed selective cytotoxicity in highly EpCAM-expressing cancer cell lines. The combination of EpCAM CAR-T with the Wnt inhibitor-hsBCL9_CT-24 displayed synergetic effect against EpCAM-positive colon cells in vitro and also in vivo. A mechanistic study showed that hsBCL9_CT-24 treatment could modulate the tumor environment and improve infiltration of T cells, while possibly promoting the effector T cells at the early stages and postponing the exhaustion of CAR T cells at advanced stages. Overall, these results demonstrated that the combination of EpCAM CAR T-cell therapy with the Wnt inhibitor can overcome the limitations of CAR T cells in treating solid tumors.

Cell Therapy for Colorectal Cancer: The Promise of Chimeric Antigen Receptor (CAR)-T Cells

Colorectal cancer (CRC) is a global public health problem as it is the third most prevalent and the second most lethal cancer worldwide. Major efforts are underway to understand its molecular pathways as well as to define the tumour-associated antigens (TAAs) and tumour-specific antigens (TSAs) or neoantigens, in order to develop an effective treatment. Cell therapies are currently gaining importance, and more specifically chimeric antigen receptor (CAR)-T cell therapy, in which genetically modified T cells are redirected against the tumour antigen of interest. This immunotherapy has emerged as one of the most promising advances in cancer treatment, having successfully demonstrated its efficacy in haematological malignancies. However, in solid tumours, such as colon cancer, it is proving difficult to achieve the same results due to the shortage of TSAs, on-target off-tumour effects, low CAR-T cell infiltration and the immunosuppressive microenvironment. To address these challenges in CRC, new approaches are proposed, including combined therapies, the regional administration of CAR-T cells and more complex CAR structures, among others. This review comprehensively summarises the current landscape of CAR-T cell therapy in CRC from the potential tumour targets to the preclinical studies and clinical trials, as well as the limitations and future perspectives of this novel antitumour strategy.

Epithelial-to-Mesenchymal Plasticity in Circulating Tumor Cell Lines Sequentially Derived from a Patient with Colorectal Cancer

Simple Summary

Metastasis is a complex dynamic multistep process; however, our knowledge is still limited. Very few circulating tumor cells (CTCs) are metastatic precursor cells and represent the intermediate stage of metastasis. Epithelial–mesenchymal plasticity (EMP) has crucial roles in tissue development and homeostasis, and also in metastasis formation. In this study, we explored the EMP phenotype of a unique series of CTC lines, obtained from a patient with colon cancer during the disease course and treatment, by detecting markers involved in the epithelial–mesenchymal and mesenchymal–epithelial (MET) transitions. This study shows that these colon CTC lines have acquired only few mesenchymal features to migrate and intravasate, whereas an increase of MET-related markers was observed, suggesting that metastasis-competent CTCs need to revert quickly to the epithelial phenotype to reinitiate a tumor at a distant site.

Abstract

Metastasis is a complicated and only partially understood multi-step process of cancer progression. A subset of cancer cells that can leave the primary tumor, intravasate, and circulate to reach distant organs are called circulating tumor cells (CTCs). Multiple lines of evidence suggest that in metastatic cancer cells, epithelial and mesenchymal markers are co-expressed to facilitate the cells’ ability to go back and forth between cellular states. This feature is called epithelial-to-mesenchymal plasticity (EMP). CTCs represent a unique source to understand the EMP features in metastatic cascade biology. Our group previously established and characterized nine serial CTC lines from a patient with metastatic colon cancer. Here, we assessed the expression of markers involved in epithelial–mesenchymal (EMT) and mesenchymal–epithelial (MET) transition in these unique CTC lines, to define their EMP profile. We found that the oncogenes MYC and ezrin were expressed by all CTC lines, but not SIX1, one of their common regulators (also an EMT inducer). Moreover, the MET activator GRHL2 and its putative targets were strongly expressed in all CTC lines, revealing their plasticity in favor of an increased MET state that promotes metastasis formation.

Epithelial-to-Mesenchymal Transition-Derived Heterogeneity in Head and Neck Squamous Cell Carcinomas

Simple Summary

Head and neck squamous cell carcinomas (HNSCC) are common malignancies with considerable morbidity and a high death toll worldwide. Resistance towards multi-modal therapy modalities composed of surgery, irradiation, chemo- and immunotherapy represents a major obstacle in the efficient treatment of HNSCC patients. Patients frequently show nodal metastases at the time of diagnosis and endure early relapses, oftentimes in the form of local recurrences. Differentiation programs such as the epithelial-to-mesenchymal transition (EMT) allow individual tumor cells to adopt cellular functions that are central to the development of metastases and treatment resistance. In the present review article, the molecular basis and regulation of EMT and its impact on the progression of HNSCC will be addressed.

Abstract

Head and neck squamous cell carcinomas (HNSCC) are common tumors with a poor overall prognosis. Poor survival is resulting from limited response to multi-modal therapy, high incidence of metastasis, and local recurrence. Treatment includes surgery, radio(chemo)therapy, and targeted therapy specific for EGFR and immune checkpoint inhibition. The understanding of the molecular basis for the poor outcome of HNSCC was improved using multi-OMICs approaches, which revealed a strong degree of inter- and intratumor heterogeneity (ITH) at the level of DNA mutations, transcriptome, and (phospho)proteome. Single-cell RNA-sequencing (scRNA-seq) identified RNA-expression signatures related to cell cycle, cell stress, hypoxia, epithelial differentiation, and a partial epithelial-to-mesenchymal transition (pEMT). The latter signature was correlated to nodal involvement and adverse clinical features. Mechanistically, shifts towards a mesenchymal phenotype equips tumor cells with migratory and invasive capacities and with an enhanced resistance to standard therapy. Hence, gradual variations of EMT as observed in HNSCC represent a potent driver of tumor progression that could open new paths to improve the stratification of patients and to innovate approaches to break therapy resistance. These aspects of molecular heterogeneity will be discussed in the present review.

The expression and clinical significance of GPR39 in colon cancer

BACKGROUND

Colorectal cancer is the third most common cancer and requires more prognostic biomarkers for precise treatment. GPR39 is a GPCR which can interact with Zn and modulate the colonocytes' survival. The clinical significance of GPR39 in colon cancer has never been reported.

MATERIALS

In our study, we compared GPR39 expression between colon cancers and tumor-adjacent tissues by retrieving TCGA data and detected the expression of GPR39 in colon cancers with qPCR and immunohistochemistry. The clinical significance of GPR39 was evaluated by analyzing the correlations with clinicopathological factors with the chi-square test. The prognostic significance of GPR39 was estimated with univariate and multivariate analyses. The expression of several other biomarkers including PPARG, EPCAM, and PD-L1 was investigated by re-analyzing TCGA data, qPCR, and IHC. The prognostic value of PPARG, EPCAM, and PD-L1 was also estimated with univariate analysis.

RESULTS

In both TCGA database and our 15 colon cancer pairs, GPR39 expression was significantly upregulated in colon cancer tissues. GPR39 was an independent prognostic biomarker in colon cancer for poor prognosis. With TCGA data re-analysis, qPCR, and IHC, we showed that GPR39 expression was significantly correlated with the expression of EPCAM and PD-L1, but not PPARG. EPCAM and PD-L1 were also unfavorable prognostic biomarkers of colon cancer.

CONCLUSIONS

GPR39 was upregulated in colon cancer tissues compared with tumor-adjacent tissues. GPR39 was an independent prognostic biomarker in colon cancer for poor prognosis. EPCAM and PD-L1 were substantially associated with GPR39 expression, and they were also identified as prognostic biomarkers in colon cancers.

EGFR tyrosine kinase inhibitor Almonertinib induces apoptosis and autophagy mediated by reactive oxygen species in non-small cell lung cancer cells

Almonertinib, a new third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, is highly selective to EGFR T790M-mutant non-small cell lung cancer (NSCLC). However, there is no available information on the form and molecular mechanism of Almonertinib-induced death in NSCLC cells. Herein, CCK-8 and colony formation assays, flow cytometry, electron microscopy, and western blots assay showed that Almonertinib inhibited NSCLC cells growth and proliferation by inducing apoptosis and autophagy which can be inhibited by a broad spectrum of caspase inhibitor Z-VAD-fmk or autophagy inhibitor chloroquine. Importantly, Almonertinib-induced autophagy was cytoprotective in NSCLC cells, and the blockade of autophagy improved cell apoptosis. In addition, Almonertinib increased reactive oxygen species (ROS) generation and clearance of ROS through pretreatment with N-acetyl-L-cysteine (NAC) inhibited the decrease of cell viability, apoptosis and increase of LC3-II induced by Almonertinib. The results of Western blot showed that both EGFR activity and downstream signaling pathways were inhibited by Almonertinib. Taken together, these findings indicated that Almonertinib induced apoptosis and autophagy by promoting ROS production in NSCLC cells.

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.

Destabilization of EpCAM dimer is associated with increased susceptibility towards cleavage by TACE

The cell-surface protein EpCAM is a carcinoma marker utilized in diagnostics and prognostics, and a promising therapeutic target. It is involved in nuclear signaling via regulated intramembrane proteolysis (RIP). Many aspects of this process are not fully understood, including the events at the molecular level leading to the exposure of cleavage sites, buried at the dimerization interface. To investigate the effect of dimer stability on cleavage susceptibility we prepared two mutants of human EpCAM ectodomain: a monomeric form, and a disulfide-stabilized dimeric form. We show that the disulfide-stabilized dimer is resistant to tumor necrosis factor-α-converting enzyme (TACE) cleavage, while the monomeric form is more susceptible than the predominantly dimeric wild type. This provides experimental evidence that the oligomeric state of EpCAM is a determinant in RIP and demonstrates the usefulness of the oligomeric state-specific mutants in investigations of EpCAM biological function.

Programmed Death-Ligand 1 as a Regulator of Tumor Progression and Metastasis

Programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) immune checkpoint has long been implicated in modeling antitumor immunity; PD-1/PD-L1 axis inhibitors exert their antitumor effects by relieving PD-L1-mediated suppression on tumor-infiltrating T lymphocytes. However, recent studies have unveiled a distinct, tumor-intrinsic, potential role for PD-L1. In this review, we focus on tumor-intrinsic PD-L1 signaling and delve into preclinical evidence linking PD-L1 protein expression with features of epithelial-to-mesenchymal transition program, cancer stemness and known oncogenic pathways. We further summarize data from studies supporting the prognostic significance of PD-L1 in different tumor types. We show that PD-L1 may indeed have oncogenic potential and act as a regulator of tumor progression and metastasis.

Pro-Tumoral Functions of Autophagy Receptors in the Modulation of Cancer Progression

Cancer progression involves a variety of pro-tumorigenic biological processes including cell proliferation, migration, invasion, and survival. A cellular pathway implicated in these pro-tumorigenic processes is autophagy, a catabolic route used for recycling of cytoplasmic components to generate macromolecular building blocks and energy, under stress conditions, to remove damaged cellular constituents to adapt to changing nutrient conditions and to maintain cellular homeostasis. During autophagy, cells form a double-membrane sequestering a compartment termed the phagophore, which matures into an autophagosome. Following fusion with the lysosome, the cargo is degraded inside the autolysosomes and the resulting macromolecules released back into the cytosol for reuse. Cancer cells use this recycling system during cancer progression, however the key autophagy players involved in this disease is unclear. Accumulative evidences show that autophagy receptors, crucial players for selective autophagy, are overexpressed during cancer progression, yet the mechanisms whereby pro-tumorigenic biological processes are modulated by these receptors remains unknown. In this review, we summarized the most important findings related with the pro-tumorigenic role of autophagy receptors p62/SQSTM1, NBR1, NDP52, and OPTN in cancer progression. In addition, we showed the most relevant cargos degraded by these receptors that have been shown to function as critical regulators of pro-tumorigenic processes. Finally, we discussed the role of autophagy receptors in the context of the cellular pathways implicated in this disease, such as growth factors signaling, oxidative stress response and apoptosis. In summary, we highlight that autophagy receptors should be considered important players of cancer progression, which could offer a niche for the development of novel diagnosis and cancer treatment strategies.

EpCAM Signaling Promotes Tumor Progression and Protein Stability of PD-L1 through the EGFR Pathway

Although epithelial cell adhesion molecule (EpCAM) has previously been shown to promote tumor progression, the underlying mechanisms remain largely unknown. Here, we report that the EGF-like domain I within the extracellular domain of EpCAM (EpEX) binds EGFR, activating both AKT and MAPK signaling to inhibit forkhead transcription factor O3a (FOXO3a) function and stabilize PD-L1 protein, respectively. Treatment with the EpCAM neutralizing antibody, EpAb2-6, inhibited AKT and FOXO3a phosphorylation, increased FOXO3a nuclear translocation, and upregulated high temperature requirement A2 (HtrA2) expression to promote apoptosis while decreasing PD-L1 protein levels to enhance the cytotoxic activity of CD8⁺ T cells. In vivo, EpAb2-6 markedly extended survival in mouse metastasis and orthotopic models of human colorectal cancer. The combination of EpAb2-6 with atezolizumab, an anti-PD-L1 antibody, almost completely eliminated tumors. Moreover, the number of CD8⁺ T cells in combination-treated tumors was increased compared with atezolizumab alone. Our findings suggest a new combination strategy for cancer immunotherapy in patients with EpCAM-expressing tumors. SIGNIFICANCE: This study shows that treatment with an EpCAM neutralizing antibody promotes apoptosis while decreasing PD-L1 protein to enhance cytotoxic activity of CD8⁺ T cells.

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

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

Vandetanib inhibits cell growth in EGFR-expressing cutaneous squamous cell carcinoma

Advanced cutaneous squamous cell carcinoma (SCC) responds poorly to chemotherapy, leading to significant morbidity or death. Overexpression of epidermal growth factor receptor (EGFR) is frequently observed in advanced cutaneous SCC. Vandetanib is a multiple tyrosine kinase targeting vascular endothelial growth factor receptor-2 (VEGFR2), EGFR, and the rearranged during transfection (RET) proto-oncogene. Vandetanib has been reported to inhibit tumor growth in head and neck SCC. However, the efficacy of vandetanib against cutaneous SCC has not been thoroughly investigated. The aim of this study is to evaluate the efficacy of vandetanib against cutaneous SCC in vitro and in vivo. Vandetanib is found to inhibit the proliferation of cutaneous SCC cells as assessed by cell viability and clonogenic assay. Cell death analysis indicates that vandetanib induces cell death in SCC cells but not in normal human keratinocytes or fibroblasts. The in vivo anti-tumor effect of vandetanib is shown in xenograft tumor models using A431 SCC cells. Mechanistically, vandetanib suppresses the phosphorylation of EGFR in SCC cells. Clinically, EGFR expression levels are elevated in cutaneous SCC specimens, relative to normal epidermis. In conclusion, we identified vandetanib as a novel therapeutic option for cutaneous SCC, especially in tumors with high EGFR expression.

Novel monoclonal antibody against integrin α3 shows therapeutic potential for ovarian cancer

Ovarian cancer has a high recurrence rate after platinum‐based chemotherapy. To improve the treatment of ovarian cancer and identify ovarian cancer‐specific antibodies, we immunized mice with the human ovarian carcinoma cell line, SKOV‐3, and generated hybridoma clones. Several rounds of screening yielded 30 monoclonal antibodies (mAbs) with no cross‐reactivity to normal cells. Among these mAbs, OV‐Ab 30‐7 was found to target integrin α3 and upregulate p53 and p21, while stimulating the apoptosis of cancer cells. We further found that binding of integrin α3 by OV‐Ab 30‐7 impaired laminin‐induced focal adhesion kinase phosphorylation. The mAb alone or in combination with carboplatin and paclitaxel inhibited tumor progression and prolonged survival of tumor‐bearing mice. Moreover, immunohistochemical staining of ovarian patient specimens revealed higher levels of integrin α3 in cancer cells compared with normal cells. By querying online clinical databases, we found that elevated ITGA3 expression in ovarian cancer is associated with poor prognosis. Taken together, our data suggest that the novel mAb, OV‐Ab 30‐7, may be considered as a potential therapeutic for ovarian cancer.

Epithelial Cell Adhesion Molecule: An Anchor to Isolate Clinically Relevant Circulating Tumor Cells

In the last few decades, the epithelial cell adhesion molecule (EpCAM) has received increased attention as the main membrane marker used in many enrichment technologies to isolate circulating tumor cells (CTCs). Although there has been a great deal of progress in the implementation of EpCAM-based CTC detection technologies in medical settings, several issues continue to limit their clinical utility. The biology of EpCAM and its role are not completely understood but evidence suggests that the expression of this epithelial cell-surface protein is crucial for metastasis-competent CTCs and may not be lost completely during the epithelial-to-mesenchymal transition. In this review, we summarize the most significant advantages and disadvantages of using EpCAM as a marker for CTC enrichment and its potential biological role in the metastatic cascade.

Overexpression of a panel of cancer stem cell markers enhances the predictive capability of the progression and recurrence in the early stage cholangiocarcinoma

Background

Cancer recurrence is the important problem of cholangiocarcinoma (CCA) patients, lead to a very high mortality rate. Therefore, the identification of candidate markers to predict CCA recurrence is needed in order to effectively manage the disease. This study aims to examine the predictive value of cancer stem cell (CSC) markers on the progression and recurrence of CCA patients.

Methods

The expression of 6 putative CSC markers, cluster of differentiation 44 (CD44), CD44 variant 6 (CD44v6), CD44 variants 8-10 (CD44v8-10), cluster of differentiation 133 (CD133), epithelial cell adhesion molecule (EpCAM), and aldehyde dehydrogenase 1A1 (ALDH1A1), was investigated in 178 CCA tissue samples using immunohistochemistry (IHC) and analyzed with respect to clinicopathological data and patient outcome including recurrence-free survival (RFS) and overall survival (OS). The candidate CSC markers were also investigated in serum from CCA patients, and explored for their predictive ability on CCA recurrence.

Results

Elevated protein level of CD44 and positive expression of CD44v6 and CD44v8-10 were significantly associated with short RFS and OS, while high levels of ALDH1A1 were correlated with a favorable prognosis patient. The elevated CD44v6 level was also correlated with higher tumor staging, whereas a decreasing level of ALDH1A1 was correlated with lower tumor staging. The levels of CD44, CD44v6 and CD44v8-10 were also correlated and were associated with a poor outcome. Furthermore, soluble CD44, CD44v6, CD44v8-10 and EpCAM were significantly increased in the recurrence group for early stage CCA; they also correlated with high levels of the tumor marker CA19-9. Elevated levels of CD44, CD44v6, CD44v8-10 or EpCAM alone or in combination has the potential to predict CCA recurrence.

Conclusions

The overexpression of CD44, CD44v6, CD44v8-10 and EpCAM increases predictability of post-operative CCA recurrence. Moreover, the overexpression of the panel of CSC markers combined with CA19-9 could improve our predictive ability for tumor recurrence in early stage CCA patients. This result may be beneficial for the patients in order to predict the outcome after treatment and may be useful for clinical intervention in order to improve patient survival.

Revisiting the Roles of Pro-Metastatic EpCAM in Cancer

Epithelial cell adhesion molecule (EpCAM) is a cell surface protein that was discovered as a tumour marker of epithelial origins nearly four decades ago. EpCAM is expressed at basal levels in the basolateral membrane of normal epithelial cells. However, EpCAM expression is upregulated in solid epithelial cancers and stem cells. EpCAM can also be found in disseminated tumour cells and circulating tumour cells. Various OMICs studies have demonstrated that EpCAM plays roles in several key biological processes such as cell adhesion, migration, proliferation and differentiation. Additionally, EpCAM can be detected in the bodily fluid of cancer patients suggesting that EpCAM is a pathophysiologically relevant anti-tumour target as well as being utilized as a diagnostic/prognostic agent for a variety of cancers. This review will focus on the structure-features of EpCAM protein and discuss recent evidence on the pathological and physiological roles of EpCAM in modulating cell adhesion and signalling pathways in cancers as well as deliberating the clinical implication of EpCAM as a therapeutic target.

The Vitamin D status is associated with serum C-reactive protein and adhesion molecules in patients with renal cell carcinoma

Low vitamin D status is associated with an increased risk of renal cell carcinoma (RCC). This study investigated the association of vitamin D status with serum C-reactive protein (CRP) and adhesion molecules among RCC patients. Fifty newly diagnosed RCC patients and 100 age- and sex-matched controls were recruited. As expected, serum 25(OH)D level was lower in RCC patients than in controls. By contrast, serum levels of CRP, an inflammatory molecule, and ICAM, LAMA4 and EpCAM, three adhesion molecules, were higher in RCC patients than in controls. All RCC patients were divided into two groups: H-VitD (>20 ng/ml) or L-VitD (<20 ng/ml). Interestingly, the levels of serum CRP and all adhesion molecules were higher in RCC patients with L-VitD than those with H-VitD. Nuclear vitamin D receptor (VDR) was downregulated and nuclear factor kappa B (NF-κB) was activated in cancerous tissues. The in vitro experiments found that VitD3 suppressed NF-κB activation and adhesion molecules in RCC cells. Moreover, VitD3 suppressed NF-κB through reinforcing physical interaction between VDR and NF-κB p65 subunit in RCC cells. These results provide a mechanistic explanation for the association among low vitamin D status, local inflammation and increased expression of adhesion molecules among RCC patients.

Targeting Autophagy for Overcoming Resistance to Anti-EGFR Treatments

Epidermal growth factor receptor (EGFR) plays critical roles in cell proliferation, tumorigenesis, and anti-cancer drug resistance. Overexpression and somatic mutations of EGFR result in enhanced cancer cell survival. Therefore, EGFR can be a target for the development of anti-cancer therapy. Patients with cancers, including non-small cell lung cancers (NSCLC), have been shown to response to EGFR-tyrosine kinase inhibitors (EGFR-TKIs) and anti-EGFR antibodies. However, resistance to these anti-EGFR treatments has developed. Autophagy has emerged as a potential mechanism involved in the acquired resistance to anti-EGFR treatments. Anti-EGFR treatments can induce autophagy and result in resistance to anti-EGFR treatments. Autophagy is a programmed catabolic process stimulated by various stimuli. It promotes cellular survival under these stress conditions. Under normal conditions, EGFR-activated phosphoinositide 3-kinase (PI3K)/AKT serine/threonine kinase (AKT)/mammalian target of rapamycin (mTOR) signaling inhibits autophagy while EGFR/rat sarcoma viral oncogene homolog (RAS)/mitogen-activated protein kinase kinase (MEK)/mitogen-activated protein kinase (MAPK) signaling promotes autophagy. Thus, targeting autophagy may overcome resistance to anti-EGFR treatments. Inhibitors targeting autophagy and EGFR signaling have been under development. In this review, we discuss crosstalk between EGFR signaling and autophagy. We also assess whether autophagy inhibition, along with anti-EGFR treatments, might represent a promising approach to overcome resistance to anti-EGFR treatments in various cancers. In addition, we discuss new developments concerning anti-autophagy therapeutics for overcoming resistance to anti-EGFR treatments in various cancers.

Expression of the potential therapeutic target claudin-18.2 is frequently decreased in gastric cancer: results from a large Caucasian cohort study

Gastric cancer (GC) is frequently diagnosed and treated in advanced tumour stages with poor prognosis. Recent studies have identified isoform 2 of the tight junction protein claudin-18 (CLDN18.2) as a promising target in GC therapy. In this study, we aimed to outline the expression of CLDN18.2 and its correlation with clinico-pathological patient characteristics in a large and well-characterized cohort of GC patients. The expression of CLDN18.2 was studied in 481 GCs by immunohistochemistry on whole tissue sections. Immunostained GCs were evaluated using the histoscore (H-score) and subsequently divided into two groups: tumours showing any or no expression. CLDN18.2 expression was investigated for correlation with various clinico-pathological patient characteristics, including survival. CLDN18.2 expression was found in 203 GCs (42.2%). Of these tumours, 71 (14.8%) showed solely weak immunostaining. CLDN18.2 expression correlated with mucin phenotype, EBV status, the integrin αvβ5, the EpCAM extracellular domain EpEX, and lysozyme. We found no correlation with survival, Laurén phenotype, or any other clinico-pathological patient characteristic. In conclusion, we demonstrate frequently decreased expression of CLDN18.2 in a GC cohort of appropriate size. Correlating CLDN18.2 expression with clinico-pathological patient characteristics reveals new linkages to αvβ5, EpEX, and lysozyme, which may pave the way for further investigations regarding the role of tight junction proteins in GC progression. Though CLDN18.2 continues to pose an attractive target candidate, we conclude that a rather low overall expression rate challenges its significance in advanced GC therapy and indicates the need for further investigations across different populations.

Immunocyte Profiling Using Single-Cell Mass Cytometry Reveals EpCAM+ CD4+ T Cells Abnormal in Colon Cancer

Colon cancer (CC) is one of the leading causes of cancer related mortality. Research over past decades have profoundly enhanced our understanding of immunotherapy, a major clinical accomplishment, and its potential role toward treating CC. However, studies investigating the expression of these immune checkpoints, such as epithelial cell adhesion molecule (EpCAM), programmed death-1 (PD-1), and programmed death-ligand 1 (PD-L1), by peripheral blood mononuclear cells (PBMCs) is lacking. Here, high-dimensional mass cytometry (CyTOF) is used to investigate immune alterations and promising immunotherapeutic targets expression by PBMCs of CC patients. Results reveal that expression of EpCAM and PD-L1 on CD4⁺ T cells significantly increased in patients with CC, compared with age- and sex- matching healthy controls and patients with colonic polyps. These differences are also validated in an independent patient cohort using flow cytometry. Further analysis revealed that EpCAM⁺ CD4⁺ T cells are PD-L1⁺ CCR5⁺ CCR6⁺. Immunofluorescence staining results demonstrate that the increase of EpCAM⁺ CD4⁺ T cells is also observed in tumor tissues, rather than para-cancerous tissues. To ascertain the functional disorders of the identified cell subset, phosphorylated signaling protein levels are assessed using imaging mass cytometry. Increases in pp38 MAPK and pMAPKAPK2 are observable, indicating abnormal activation of pp38 MAPK-pMAPKAPK2 signaling pathway. Results in this study indicate that EpCAM⁺ CD4⁺ T cells may play a role in CC development. Detailed knowledge on the functionality of EpCAM⁺ CD4⁺ T cells is of high translational relevance.

The extracellular domain of epithelial cell adhesion molecule (EpCAM) enhances multipotency of mesenchymal stem cells through EGFR-LIN28-LET7 signaling

Mesenchymal stem cells (MSCs) are widely considered to be an attractive cell source for regenerative therapies, but maintaining multipotency and self-renewal in cultured MSCs is especially challenging. Hence, the development and mechanistic description of strategies that help promote multipotency in MSCs will be vital to future clinical use. Here, using an array of techniques and approaches, including cell biology, RT-quantitative PCR, immunoblotting, immunofluorescence, flow cytometry, and ChIP assays, we show that the extracellular domain of epithelial cell adhesion molecule (EpCAM) (EpEX) significantly increases the levels of pluripotency factors through a signaling cascade that includes epidermal growth factor receptor (EGFR), signal transducer and activator of transcription 3 (STAT3), and Lin-28 homolog A (LIN28) and enhances the proliferation of human bone marrow MSCs. Moreover, we found that EpEX-induced LIN28 expression reduces the expression of the microRNA LET7 and up-regulates that of the transcription factor high-mobility group AT-hook 2 (HMGA2), which activates the transcription of pluripotency factors. Surprisingly, we found that EpEX treatment also enhances osteogenesis of MSCs under differentiation conditions, as evidenced by increases in osteogenic markers, including Runt-related transcription factor 2 (RUNX2). Taken together, our results indicate that EpEX stimulates EGFR signaling and thereby context-dependently controls MSC states and activities, promoting cell proliferation and multipotency under maintenance conditions and osteogenesis under differentiation conditions.

Membrane-associated epithelial cell adhesion molecule is slowly cleaved by γ-secretase prior to efficient proteasomal degradation of its intracellular domain

Regulated intramembrane proteolysis (RIP) is a key mechanism for activating transmembrane proteins such as epithelial cell adhesion molecule (EpCAM) for cellular signaling and degradation. EpCAM is highly expressed in carcinomas and progenitor and embryonic stem cells and is involved in the regulation of cell adhesion, proliferation, and differentiation. Strictly sequential cleavage of EpCAM through RIP involves initial shedding of the extracellular domain by α-secretase (ADAM) and β-secretase (BACE) sheddases, generating a membrane-tethered C-terminal fragment EpCTF. Subsequently, the rate-limiting γ-secretase complex catalyzes intramembrane cleavage of EpCTF, generating an extracellular EpCAM-Aβ-like fragment and an intracellular EpICD fragment involved in nuclear signaling. Here, we have combined biochemical approaches with live-cell imaging of fluorescent protein tags to investigate the kinetics of γ-secretase-mediated intramembrane cleavage of EpCTF. We demonstrate that γ-secretase-mediated proteolysis of exogenously and endogenously expressed EpCTF is a slow process with a 50% protein turnover in cells ranging from 45 min to 5.5 h. The slow cleavage was dictated by γ-secretase activity and not by EpCTF species, as indicated by cross-species swapping experiments. Furthermore, both human and murine EpICDs generated from EpCTF by γ-secretase were degraded efficiently (94-99%) by the proteasome. Hence, proteolytic cleavage of EpCTF is a comparably slow process, and EpICD generation does not appear to be suited for rapidly transducing extracellular cues into nuclear signaling, but appears to provide steady signals that can be further controlled through efficient proteasomal degradation. Our approach provides an unbiased bioassay to investigate proteolytic processing of EpCTF in single living cells.

Proteomic profiling reveals key cancer progression modulators in shed microvesicles released from isogenic human primary and metastatic colorectal cancer cell lines

Extracellular vesicles comprise two main classes - exosomes and shed microvesicles (sMVs). Whilst much is known about exosome cargo content and functionality, sMVs are poorly understood. Here, we describe the large-scale purification of sMVs released from primary (SW480) and metastatic (SW620) human isogenic colorectal cancer (CRC) cell lines using a combination of differential ultracentrifugation and isopycnic iodixanol density centrifugation. The yield of SW480-sMVs and SW620-sMVs was 0.75 mg and 0.80 mg, respectively. Both SW480-/SW620-sMVs are heterogeneous in size (100-600 nm diameter) and exhibit identical buoyant densities (1.10 g/mL). In contrast to exosomes, sMVs are ALIX^-, TSG101^-, CD63^- and CD9^-. Quantitative mass spectrometry identified 1295 and 1300 proteins in SW480-sMVs and SW620-sMVs, respectively. Gene Ontology enrichment analysis identified 'cell adhesion' (CDH1, OCLN, CTN families), 'signalling pathway' (KRAS, NRAS, MAPK1, MAP2K1), and 'translation/RNA related' processes (EIF, RPL, HNRNP families) in both sMV types. Strikingly, SW480- and SW620-sMVs exhibit distinct protein signatures - SW480-sMVs being enriched in ITGA/B, ANXA1, CLDN7, CD44 and EGFR/NOTCH signalling networks, while SW620-sMVs are enriched in PRKCA, MACC1, FGFR4 and MTOR/MARCKS signalling networks. Both SW480- and SW620-sMVs are taken up by NIH3T3 fibroblasts resulting in similar cell invasion capability. This study provides, for the first time, molecular insights into sMVs and CRC biology.

EpCAM ectodomain EpEX is a ligand of EGFR that counteracts EGF-mediated epithelial-mesenchymal transition through modulation of phospho-ERK1/2 in head and neck cancers

Head and neck squamous cell carcinomas (HNSCCs) are characterized by outstanding molecular heterogeneity that results in severe therapy resistance and poor clinical outcome. Inter- and intratumoral heterogeneity in epithelial-mesenchymal transition (EMT) was recently revealed as a major parameter of poor clinical outcome. Here, we addressed the expression and function of the therapeutic target epidermal growth factor receptor (EGFR) and of the major determinant of epithelial differentiation epithelial cell adhesion molecule (EpCAM) in clinical samples and in vitro models of HNSCCs. We describe improved survival of EGFR^low/EpCAM^high HNSCC patients (n = 180) and provide a molecular basis for the observed disparities in clinical outcome. EGF/EGFR have concentration-dependent dual capacities as inducers of proliferation and EMT through differential activation of the central molecular switch phosphorylated extracellular signal–regulated kinase 1/2 (pERK1/2) and EMT transcription factors (EMT-TFs) Snail, zinc finger E-box-binding homeobox 1 (Zeb1), and Slug. Furthermore, soluble ectodomain of EpCAM (EpEX) was identified as a ligand of EGFR that activates pERK1/2 and phosphorylated AKT (pAKT) and induces EGFR-dependent proliferation but represses EGF-mediated EMT, Snail, Zeb1, and Slug activation and cell migration. EMT repression by EpEX is realized through competitive modulation of pERK1/2 activation strength and inhibition of EMT-TFs, which is reflected in levels of pERK1/2 and its target Slug in clinical samples. Accordingly, high expression of pERK1/2 and/or Slug predicted poor outcome of HNSCCs. Hence, EpEX is a ligand of EGFR that induces proliferation but counteracts EMT mediated by the EGF/EGFR/pERK1/2 axis. Therefore, the emerging EGFR/EpCAM molecular cross talk represents a promising target to improve patient-tailored adjuvant treatment of HNSCCs.

Head and neck squamous cell carcinomas (HNSCCs) display poor survival, with death rates above 55%. Major factors affecting survival are metastases’ formation and therapy resistance. Phenotypic changes during partial epithelial-mesenchymal transition (EMT) provide tumor cells with increased migration, invasion, and therapy resistance. Understanding molecular mechanisms of EMT, as a central process of the metastatic cascade and the development of therapy resistance, is therefore important. In the present work, we identified molecular cross talk between epidermal growth factor receptor (EGFR) and epithelial cell adhesion molecule (EpCAM) as a novel determinant of clinical outcome in HNSCCs. Low levels of EGFR but high levels of EpCAM (EGFR^low/EpCAM^high) were associated with favorable prognosis, with survival rates above 90%, whereas EGFR^high/EpCAM^low correlated with poor survival, below 10%. EGFR was shown to have a concentration-dependent capacity to induce proliferation and EMT. Proteolytic cleavage of the extracellular domain of EpCAM (EpEX) produces a ligand of EGFR that induces EGFR-dependent proliferation but counteracts EGF-induced EMT. We delineate an EGFR/extracellular signal–regulated kinase 1/2 (ERK1/2)/EpCAM signaling axis that may be a promising therapeutic target for HNSCCs.