Serine/threonine-protein kinase D2-mediated phosphorylation of DSG2 threonine 730 promotes esophageal squamous cell carcinoma progression.

Desmoglein-2 (DSG2) is a transmembrane glycoprotein belonging to the desmosomal cadherin family, which mediates cell-cell junctions; regulates cell proliferation, migration, and invasion; and promotes tumor development and metastasis. We previously showed serum DSG2 to be a potential biomarker for the diagnosis of esophageal squamous cell carcinoma (ESCC), although the significance and underlying molecular mechanisms were not identified. Here, we found that DSG2 was increased in ESCC tissues compared with adjacent tissues. In addition, we demonstrated that DSG2 promoted ESCC cell migration and invasion. Furthermore, using interactome analysis, we identified serine/threonine-protein kinase D2 (PRKD2) as a novel DSG2 kinase that mediates the phosphorylation of DSG2 at threonine 730 (T730). Functionally, DSG2 promoted ESCC cell migration and invasion dependent on DSG2-T730 phosphorylation. Mechanistically, DSG2 T730 phosphorylation activated EGFR, Src, AKT, and ERK signaling pathways. In addition, DSG2 and PRKD2 were positively correlated with each other, and the overall survival time of ESCC patients with high DSG2 and PRKD2 was shorter than that of patients with low DSG2 and PRKD2 levels. In summary, PRKD2 is a novel DSG2 kinase, and PRKD2-mediated DSG2 T730 phosphorylation promotes ESCC progression. These findings may facilitate the development of future therapeutic agents that target DSG2 and DSG2 phosphorylation. © 2024 The Pathological Society of Great Britain and Ireland.

Super-Enhancer-Driven Long Non-Coding RNA LINC01503, Regulated by TP63, Is Over-Expressed and Oncogenic in Squamous Cell Carcinoma.

BACKGROUND & AIMS: Long non-coding RNAs (lncRNAs) are expressed in tissue-specific pattern, but it is not clear how these are regulated. We aimed to identify squamous cell carcinoma (SCC)-specific lncRNAs and investigate mechanisms that control their expression and function. METHODS: We studied expression patterns and functions of 4 SCC-specific lncRNAs. We obtained 113 esophageal SCC (ESCC) and matched non-tumor esophageal tissues from a hospital in Shantou City, China, and performed quantitative reverse transcription polymerase chain reaction assays to measure expression levels of LINC01503. We collected clinical data from patients and compared expression levels with survival times. LINC01503 was knocked down using small interfering RNAs and oligonucleotides in TE7, TE5, and KYSE510 cell lines and overexpressed in KYSE30 cells. Cells were analyzed by chromatin immunoprecipitation sequencing, luciferase reporter assays, colony formation, migration and invasion, and mass spectrometry analyses. Cells were injected into nude mice and growth of xenograft tumors was measured. LINC01503 interaction with proteins was studied using fluorescence in situ hybridization, RNA pulldown, and RNA immunoprecipitation analyses. RESULTS: We identified a lncRNA, LINC01503, which is regulated by a super enhancer and is expressed at significantly higher levels in esophageal and head and neck SCCs than in non-tumor tissues. High levels in SCCs correlated with shorter survival times of patients. The transcription factor TP63 bound to the super enhancer at the LINC01503 locus and activated its transcription. Expression of LINC01503 in ESCC cell lines increased their proliferation, colony formation, migration, and invasion. Knockdown of LINC01503 in SCC cells reduced their proliferation, colony formation, migration, and invasion, and the growth of xenograft tumors in nude mice. Expression of LINC01503 in ESCC cell lines reduced ERK2 dephosphorylation by DUSP6, leading to activation of ERK signaling via MAPK. LINC01503 disrupted the interaction between EBP1 and the p85 subunit of PI3K, increasing AKT signaling. CONCLUSIONS: We identified an lncRNA, LINC01503, which is increased in SCC cells compared with non-tumor cells. Increased expression of LINC01503 promotes ESCC cell proliferation, migration, invasion, and growth of xenograft tumors. It might be developed as a biomarker of aggressive SCCs in patients.

Lipocalin 2 promotes the migration and invasion of esophageal squamous cell carcinoma cells through a novel positive feedback loop.

Lipocalin 2 (LCN2) is a poor prognostic factor in esophageal squamous cell carcinoma (ESCC), however its functional roles and molecular mechanisms of action remain to be clarified. Here, we described the functions and signaling pathways for LCN2 in ESCC. Overexpression of LCN2 in ESCC cells accelerated cell migration and invasion in vitro, and promoted lung metastasis in vivo. Blocking LCN2 expression inhibited its pro-oncogenic effect. Either overexpression of LCN2 or treatment with recombinant human LCN2 protein enhanced the activation of MEK/ERK pathway, which in turn increases endogenous LCN2 to increase MMP-9 activity. The decreased p-cofilin and increased p-ERM induced by pERK1/2 cause the cytoskeleton F-actin rearrangement and alter the behavior of ESCC cells mediated by LCN2. As a consequence, activation of MMP-9 and the rearrangement of F-actin throw light on the mechanisms for LCN2 in ESCC. These results imply that LCN2 promotes the migration and invasion of ESCC cells through a novel positive feedback loop.

Identification of a novel lysyl oxidase-like 2 alternative splicing isoform, LOXL2 Δe13, in esophageal squamous cell carcinoma.

Lysyl oxidase-like 2 (LOXL2) participates in every stage of cancer progression and promotes invasion and metastasis. In this study, we identified a novel alternative splicing isoform of LOXL2, namely LOXL2 Δe13, which lacked exon 13. Deletion of exon 13 caused an open reading frame shift and produced a truncated protein. LOXL2 Δe13 was expressed ubiquitously in cell lines and tissues and was mainly localized to the cytoplasm. Although it showed impaired deamination enzymatic activity compared with full-length LOXL2, LOXL2 Δe13 promoted the cell mobility and invasion of esophageal squamous cell carcinoma (ESCC) cells to greater degrees. In further research on the mechanisms, gene expression profiling and signaling pathway analysis revealed that LOXL2 Δe13 induced the expression of MAPK8 without affecting the FAK, AKT, and ERK signaling pathways. RNAi-mediated knockdown of MAPK8 could block the cell migration promoted by LOXL2De13, but it had little effect on that of full-length LOXL2. Our data suggest that LOXL2 Δe13 modulates the effects of cancer cell migration and invasion through a different mechanism from that of full-length LOXL2 and that it may play a very important role in tumor carcinogenesis and progression.

Down-regulated desmocollin-2 promotes cell aggressiveness through redistributing adherens junctions and activating beta-catenin signalling in oesophageal squamous cell carcinoma.

In contrast to the well-recognized loss of adherens junctions in cancer progression, the role of desmosomal components in cancer development has not been well explored. We previously demonstrated that desmocollin-2 (DSC2), a desmosomal cadherin protein, is reduced in oesophageal squamous cell carcinoma (ESCC), and is associated with enhanced tumour metastasis and poor prognosis. Here, we report that restoration of DSC2 in ESCC cells impeded cell migration and invasion both in vitro and in vivo, whereas siRNA-mediated suppression of DSC2 expression increased cell motility. In E-cadherin-expressing ESCC cells, DSC2 restoration strengthened E-cadherin-mediated adherens junctions and promoted the localization of ß-catenin at these junctions, which indirectly inhibited ß-catenin-dependent transcription. These effects of DSC2 were not present in EC109 cells that lacked E-cadherin expression. ESCC patients with tumours that had reduced E-cadherin and negative DSC2 had poorer clinical outcomes than patients with tumours that lacked either E-cadherin or DSC2, implying that the invasive potential of ESCC cells was restricted by both DSC2 and E-cadherin-dependent junctions. Further studies revealed that DSC2 was a downstream target of miR-25. Enhanced miR-25 promoted ESCC cell invasiveness, whereas restoration of DSC2 abolished these effects. Collectively, our work suggests that miR-25-mediated down-regulation of DSC2 promotes ESCC cell aggressiveness through redistributing adherens junctions and activating beta-catenin signalling.

Secreted proteins encoded by super enhancer-driven genes could be promising biomarkers for early detection of esophageal squamous cell carcinoma.

BACKGROUND: Early detection of cancer remains an unmet need in clinical practice, and high diagnostic sensitivity and specificity biomarkers are urgently required. Here, we attempted to identify secreted proteins encoded by super-enhancer (SE)-driven genes as diagnostic biomarkers for esophageal squamous cell carcinoma (ESCC). METHODS: We conducted an integrative analysis of multiple data sets including ChIP-seq data, secretome data, CCLE data and GEO data to screen secreted proteins encoded by SE-driven genes. Using ELISA, we further identified up-regulated secreted proteins through a small size of clinical samples and verified in a multi-centre validation stage (345 in test cohort and 231 in validation cohort). Receiver operating characteristic curves were used to calculate diagnostic accuracy. Artificial intelligence (AI) method named gradient boosting machine (GBM) were applied for model construction to enhance diagnostic accuracy. RESULTS: Serum EFNA1 and MMP13 were identified, and showed significantly higher levels in ESCC patients compared to normal controls. An integrated Five-Biomarker Panel (iFBPanel) established by combining EFNA1, MMP13, carcino-embryonic antigen, Cyfra21-1 and squmaous cell carcinoma antigen had AUCs of 0.881 and 0.880 for ESCC in test and validation cohorts, respectively. Importantly, the iFBPanel also exhibited good performance in detecting early-stage ESCC patients (0.872 and 0.864). Furthermore, the iFBPanel was further empowered by AI technology which showed excellent diagnostic performance in early-stage ESCC (0.927 and 0.907). CONCLUSIONS: Our study suggested that serum EFNA1 and MMP13 could potentially assist ESCC detection, and provided an easy-to-use detection model that might help the diagnosis of early-stage ESCC.

Construction of the Six-lncRNA Prognosis Signature as a Novel Biomarker in Esophageal Squamous Cell Carcinoma.

Esophageal squamous cell carcinoma (ESCC) is a common malignant gastrointestinal tumor threatening global human health. For patients diagnosed with ESCC, determining the prognosis is a huge challenge. Due to their important role in tumor progression, long non-coding RNAs (lncRNAs) may be putative molecular candidates in the survival prediction of ESCC patients. Here, we obtained three datasets of ESCC lncRNA expression profiles (GSE53624, GSE53622, and GSE53625) from the Gene Expression Omnibus (GEO) database. The method of statistics and machine learning including survival analysis and LASSO regression analysis were applied. We identified a six-lncRNA signature composed of AL445524.1, AC109439.2, LINC01273, AC015922.3, LINC00547, and PSPC1-AS2. Kaplan-Meier and Cox analyses were conducted, and the prognostic ability and predictive independence of the lncRNA signature were found in three ESCC datasets. In the entire set, time-dependent ROC curve analysis showed that the prediction accuracy of the lncRNA signature was remarkably greater than that of TNM stage. ROC and stratified analysis indicated that the combination of six-lncRNA signature with the TNM stage has the highest accuracy in subgrouping ESCC patients. Furthermore, experiments subsequently confirmed that one of the lncRNAs LINC01273 may play an oncogenic role in ESCC. This study suggested the six-lncRNA signature could be a valuable survival predictor for patients with ESCC and have potential to be an auxiliary biomarker of TNM stage to subdivide ESCC patients more accurately, which has important clinical significance.

Serum DSG2 as a potential biomarker for diagnosis of esophageal squamous cell carcinoma and esophagogastric junction adenocarcinoma.

BACKGROUND: Exploration of serum biomarkers for early detection of upper gastrointestinal cancer is required. Here, we aimed to evaluate the diagnostic potential of serum desmoglein-2 (DSG2) in patients with esophageal squamous cell carcinoma (ESCC) and esophagogastric junction adenocarcinoma (EJA). METHODS: Serum DSG2 levels were measured by enzyme-linked immunosorbent assay (ELISA) in 459 participants including 151 patients with ESCC, 96 with EJA, and 212 healthy controls. Receiver operating characteristic (ROC) curves were used to evaluate diagnostic accuracy. RESULTS: Levels of serum DSG2 were significantly higher in patients with ESCC and EJA than those in healthy controls (P<0.001). Detection of serum DSG2 demonstrated an area under the ROC curve (AUC) value of 0.724, sensitivity of 38.1%, and specificity of 84.8% for the diagnosis of ESCC in the training cohort, and AUC 0.736, sensitivity 58.2%, and specificity 84.7% in the validation cohort. For diagnosis of EJA, measurement of DSG2 provided a sensitivity of 29.2%, a specificity of 90.2%, and AUC of 0.698. Similar results were observed for the diagnosis of early-stage ESCC (AUC 0.715 and 0.722, sensitivity 36.3 and 50%, and specificity 84.8 and 84.7%, for training and validation cohorts, respectively) and early-stage EJA (AUC 0.704, sensitivity 44.4%, and specificity 86.9%). Analysis of clinical data indicated that DSG2 levels were significantly associated with patient age and histological grade in ESCC (P<0.05). CONCLUSION: Serum DSG2 may be a diagnostic biomarker for ESCC and EJA.

Role of Integrin ß1 in the progression and chemo-resistance of esophageal squamous cell carcinoma.

Objective: Integrins have been shown to play an important role in the tumorigenesis of many cancers. In this work, we aimed to explore the expression and clinical value of Integrin α5ß1 in esophageal squamous cell carcinoma (ESCC), and the effect of integrin ß1 on the development and chemo-resistance of ESCC cells. Methods: The expression profiling of integrins was analyzed in the mRNA expression dataset of ESCC. The expression of Integrin α5ß1 in 278 cases of ESCC tissues and 62 cases of paracancerous tissues was detected by immunohistochemistry (IHC). The association between the expression of Integrin α5ß1 and the survival of ESCC patients was analyzed by Kaplan-Meier analysis. The effect of Integrin ß1 on the proliferation, migration, and invasion of ESCC cells was examined by MTS, Transwell migration, and Transwell invasion assay. The effect of Integrin ß1 and L1 cell adhesion molecule (L1CAM) on cisplatin resistance was detected by MTS and the signal pathways involved were analyzed by Western blotting. Results: Integrin ß1 and Integrin α5 were significantly up-regulated in ESCC. High expression of Integrin ß1 was also related to worse overall survival of ESCC patients and patients with low levels of both Integrin ß1 and Integrin α5 showed the shortest survival. Results of IHC revealed that Integrin α5ß1 was up-regulated in ESCC and its high expression was associated with poor prognosis and could serve as an independent prognostic factor. siRNA-mediated Integrin ß1 silencing or antibody blocking restrained the proliferation, migration, and invasion of ESCC cells. Simultaneous knockdown of Integrin ß1 and L1CAM reduced the cisplatin resistance of ESCC cells. Further studies showed that knockdown of Integrin ß1 and L1CAM suppressed the activity of Akt signaling with or without cisplatin treatment. Moreover, dual high expression of Integrin ß1 and L1CAM was related to worse overall survival of ESCC patients treated with preoperative chemotherapy. Conclusion: Integrin α5ß1 was up-regulated in ESCC and could be used as a new prognostic indicator for ESCC patients. In addition, Integrin ß1 was involved in the proliferation, invasion, and chemo-resistance of ESCC cells.

Role of Cell-Cell Junctions in Oesophageal Squamous Cell Carcinoma.

Cell-cell junctions comprise various structures, including adherens junctions, tight junctions, desmosomes, and gap junctions. They link cells to each other in tissues and regulate tissue homeostasis in critical cellular processes. Recent advances in cell-cell junction research have led to critical discoveries. Cell-cell adhesion components are important for the invasion and metastasis of tumour cells, which are not only related to cell-cell adhesion changes, but they are also involved in critical molecular signal pathways. They are of great significance, especially given that relevant molecular mechanisms are being discovered, there are an increasing number of emerging biomarkers, targeted therapies are becoming a future therapeutic concern, and there is an increased number of therapeutic agents undergoing clinical trials. Oesophageal squamous cell carcinoma (ESCC), the most common histological subtype of oesophageal cancer, is one of the most common cancers to affect epithelial tissue. ESCC progression is accompanied by the abnormal expression or localisation of components at cell-cell junctions. This review will discuss the recent scientific developments related to the molecules at cell-cell junctions and their role in ESCC to offer valuable insights for readers, provide a global view of the relationships between position, construction, and function, and give a reference for future mechanistic studies, diagnoses, and therapeutic developments.

Paradoxical Roles of Desmosomal Components in Head and Neck Cancer.

Desmosomes are intercellular adhesion complexes involved in various aspects of epithelial pathophysiology, including tissue homeostasis, morphogenesis, and disease development. Recent studies have reported that the abnormal expression of various desmosomal components correlates with tumor progression and poor survival. In addition, desmosomes have been shown to act as a signaling platform to regulate the proliferation, invasion, migration, morphogenesis, and apoptosis of cancer cells. The occurrence and progression of head and neck cancer (HNC) is accompanied by abnormal expression of desmosomal components and loss of desmosome structure. However, the role of desmosomal components in the progression of HNC remains controversial. This review aims to provide an overview of recent developments showing the paradoxical roles of desmosomal components in tumor suppression and promotion. It offers valuable insights for HNC diagnosis and therapeutics development.

Serum CYR61 as a potential biomarker for the diagnosis of esophagogastric junction tumor.

BACKGROUND: Esophagogastric junction tumor (EGJ) is a rare but fatal disease with a rapid rising incidence worldwide in the late 20 years, and it lacks a convenient and safe method for diagnosis. The present study aimed to evaluate the potential of serum CYR61 as a biomarker for the diagnosis of EGJ tumor. METHODS: Enzyme-linked immunosorbent assay (ELISA) was used to estimate CYR61 levels in sera of 152 EGJ tumor patients and 137 normal controls. Receiver operating characteristics (ROC) was carried out to evaluate the diagnostic accuracy. The Mann-Whitney's U test was used to compare the difference of serum levels of CYR61 between groups. And chi-square tests were employed to estimate the correlation of the positive rate of serum CYR61 between/among subgroups. RESULTS: Serum CYR61 levels were statistically lower in EGJ tumor and early-stage EGJ tumor patients than those in normal controls (P<0.0001). The sensitivity, specificity and the area under the curve (AUC) of this biomarker in EGJ tumor were 88.2%, 43.8% and 0.691, respectively, and those for early stage of EGJ tumor were 80.0%, 66.4% and 0.722, respectively. Analyses showed that there was no correlation between the clinical data and the levels of CYR61 (P>0.05). CONCLUSION: The present study showed that CYR61 might be a potential biomarker to assist the diagnosis of EGJ tumor.

The Diagnostic Value of Serum L1CAM in Patients With Colorectal Cancer.

OBJECTIVE: Colorectal cancer is one of the most important malignant cancer in the world with high incidence and mortality. Some studies have found that the expression of low serum L1 cell adhesion molecule is associated with poor prognosis in some malignancies. It is suggested that L1 cell adhesion molecule is a candidate serum marker for certain tumors. However, the relationship between serum L1 cell adhesion molecule and colorectal cancer, especially about the diagnostic value, is rarely reported. Therefore, this study aimed to evaluate the diagnostic potential of serum L1 cell adhesion molecule in patients with colorectal cancer. METHODS: Enzyme-linked immunosorbent assay was carried out to detect L1 cell adhesion molecule level in sera of 229 patients with colorectal cancer and 145 normal controls. Receiver operating characteristic curves were employed to calculate the accuracy of diagnosis. RESULTS: The levels of serum L1 cell adhesion molecule in the colorectal cancer group were significantly lower than that in normal controls (P < .05). In the normal group, the area under the receiver operating characteristic curve (area under the curve) of all colorectal cancer was 0.781 (95% confidence interval: 0.734-0.828) and early-stage colorectal cancer was 0.764 (95% confidence interval: 0.705-0.823). With optimized cutoff of 17.760 ng/mL, L1 cell adhesion molecule showed certain diagnostic value with specificity of 90.3% and sensitivities of 43.2% and 36.2% in colorectal cancer and early-stage colorectal cancer, respectively. Clinical data analysis showed that the levels of L1 cell adhesion molecule were significantly correlated with gender (P < .05) and early and late stages (P < .05). Furthermore, when compared with carcinoembryonic antigen, serum L1 cell adhesion molecule had significantly improved diagnostic accuracy for both colorectal cancer and early-stage colorectal cancer. CONCLUSIONS: Our study demonstrated that serum L1 cell adhesion molecule might be served as a potential biomarker for the diagnosis of colorectal cancer.

Circulating Levels of L1-cell Adhesion Molecule as a Serum Biomarker for Early Detection of Gastric Cancer and Esophagogastric Junction Adenocarcinoma.

Background: Low serum L1 cell adhesion molecule (L1CAM) has been found in several malignant tumors. Here, we aimed to evaluate the diagnostic potential for serum L1CAM in patients with gastric cancers (GC) and esophagogastric junction adenocarcinoma (EJA). Methods: Enzyme-linked immunosorbent assay (ELISA) was carried out to detect L1CAM level in sera of 148 GC patients, 59 EJA patients and 148 healthy controls. Receiver operating characteristics (ROC) was employed to evaluate diagnostic accuracy. Results: The concentrations of serum L1CAM were significantly lower in GC and EJA than those in healthy controls (P<0.001). Detection of L1CAM provided a sensitivity of 83.1%, a specificity of 62.2%, and an area under the curve (AUC) of 0.769 (95% CI: 0.715-0.823) in diagnosing GC, and a sensitivity of 66.1%, a specificity of 62.2%, and an AUC of 0.672 (95% CI: 0.590-0.755) in diagnosing EJA. Similar results were observed in the diagnosis of early-stage GC (0.681 (95%CI: 0.596-0.766)) and early-stage EJA (0.674 (95%CI: 0.528-0.820)). Analysis of clinical data showed that the levels of L1CAM were significantly associated with lymph node metastasis in GC (P<0.05). Conclusions: Our study showed that serum L1CAM might be a diagnostic biomarker for GC and EJA.

NGALR is overexpressed and regulated by hypomethylation in esophageal squamous cell carcinoma.

PURPOSE: Neutrophil gelatinase-associated lipocalin receptor (NGALR) mRNA level is reduced in isolated chronic myelogenous leukemia blasts but up-regulated in esophageal squamous cell carcinoma (ESCC). The mechanism of NGALR regulation is unknown. Here, we show the expression pattern of NGALR and examine the aberrant methylation of its gene in ESCC and esophageal carcinoma cell lines. EXPERIMENTAL DESIGN: The expression pattern of NGALR was analyzed by immunohistochemistry in 59 ESCCs and compared with noncancerous tissues. The DNA methylation status was investigated by methylation-specific PCR and by bisulfite genomic sequencing in esophageal carcinoma cell lines and surgically resected samples. Methylated cell lines were treated with a methylation inhibitor to restore NGALR expression. RESULTS: The expression of NGALR in ESCC was significantly higher in tumor cell membrane and cytoplasm than in normal esophageal epithelium (P < 0.01). Methylated alleles were detected in three NGALR-nonexpressing cell lines but were not detected in three NGALR-expressing cell lines. Treatment of methylated cell lines with 5-aza-2'-deoxycytidine, a methylation inhibitor, restored NGALR expression. In surgically resected samples, 31 of 77 (40.3%) primary esophageal carcinomas and 46 of 77 (59.7%) paired normal tissues contained methylated NGALR alleles (P < 0.05). CONCLUSIONS: Our results suggest that NGALR hypomethylation contributes to its expression in esophageal carcinomas and that this overexpression may play a role in the pathogenesis of esophageal carcinomas.

A novel alternative spliced variant of neutrophil gelatinase-associated lipocalin receptor in oesophageal carcinoma cells.

Recent studies suggest that NGAL (neutrophil gelatinase-associated lipocalin) is a novel iron transporter with functions distinct from that of transferrin and mediates a new iron-delivery pathway. To get a better understanding of NGAL function in oesophageal carcinoma, we analysed the expression of NGAL receptors in oesophageal carcinoma cells and identified a novel spliced variant designated NgalR-3. When expressed in a heterologous system, the protein produced from this novel spliced variant exhibits the biochemical characteristics of interaction and co-localization with NGAL protein in vivo. This new finding suggests that NgalR-3 may act as a potential NGAL receptor and play a role in NGAL-mediated iron transport in oesophageal carcinoma.

Diagnostic and prognostic value of serum L1-cell adhesion molecule in esophageal squamous cell carcinoma.

OBJECTIVE: L1 cell adhesion molecule (L1CAM) has been found to be dysregulated in several types of human cancers. Here, we aimed to determine the level of soluble L1CAM in serum of patients with esophageal squamous cell carcinoma (ESCC). METHODS: Serum levels of L1CAM were determined by an enzyme-linked immunosorbent assay (ELISA) in 191 patients with ESCC and 94 normal controls. Receiver operating characteristics (ROC) was employed to calculate diagnostic accuracy. Cumulative survival time was calculated by the Kaplan-Meier method and analyzed by the logrank test. RESULTS: Levels of L1CAM were significantly lower in all ESCC patients than in normal controls (P < 0.001). Detection of serum L1CAM provided a sensitivity of 28.3%, a specificity of 90.4% and an area under the curve (AUC) of 0.644 (95% CI: 0.579-0.710) in diagnosing ESCC. Similar results were observed in the diagnosis of early-stage ESCC (26.2% sensitivity, 90.4% specificity, and an AUC of 0.629). Moreover, decreased level of L1CAM was correlated with depth of tumor invasion (P < 0.05). Kaplan-Meier analysis showed that lower serum L1CAM level was significantly related to shorter overall survival time (P = 0.036) and disease-free survival time (P = 0.021) of ESCC patients. CONCLUSIONS: Our study demonstrated that serum L1CAM might serve as a potential biomarker for the diagnosis and prognosis of ESCC.

L1CAM drives oncogenicity in esophageal squamous cell carcinoma by stimulation of ezrin transcription.

L1 cell adhesion molecule (L1CAM) is highly expressed in various types of human cancers, displaying yet unknown molecular mechanisms underlying their oncogenic potential. Here, we found that L1CAM expression was significantly increased in esophageal squamous cell carcinoma (ESCC; n = 157) lesions compared with non-cancerous tissues. High tumorous L1CAM expression significantly correlated with reduced overall survival. Experimentally, L1CAM knockdown led to decreased cell growth, migration, and invasiveness in vitro, whereas overexpression of L1CAM showed the opposite effect. In nude mice, L1CAM depletion attenuated tumorigenesis and ability to penetrate the tissues surrounding ESCC cells. Gene set enrichment analysis (GSEA) and SubpathwayMiner analysis on gene expression profiles (microarray data on ESCC tissues, GSE53625; cDNA microarray data on L1CAM-knockdown ESCC cell line, GSE86268) suggested that L1CAM-co-expression genes were related to cell motility, cell proliferation, and regulation of actin cytoskeleton, validating the above experimental findings. Further mechanistical analysis showed that L1CAM upregulated the expression of the cytoskeletal protein ezrin via activating integrin ß1/MAPK/ERK/AP1 signaling and thus led to the malignant phenotypes of ESCC cells. Together, our findings suggest that L1CAM may be employed as a valuable prognosis marker and a therapeutic target for ESCC patients and that L1CAM promotes ESCC tumorigenicity by upregulating ezrin expression. KEY MESSAGES: L1CAM promotes growth and invasiveness of ESCC cells in vitro and in vivo. L1CAM upregulates the expression of ezrin by integrin α5ß1/MAPK/ERK/AP1 pathway. Ezrin is a key downstream effector in the L1CAM-promoted malignant phenotypes. High expression levels of both L1CAM and ezrin significantly correlated with reduced overall survival. Nuclear L1CAM is an independent prognosis marker for esophageal squamous cell carcinoma.

Desmocollin­2 affects the adhesive strength and cytoskeletal arrangement in esophageal squamous cell carcinoma cells.

Desmocollin­2 (DSC2), a transmembrane glycoprotein belonging to the desmosomal cadherin family, has been found to be differentially expressed in several types of cancer and to be involved in tumor progression. The tumor metastasis suppressing property of DSC2 in esophageal squamous cell carcinoma (ESCC) has been described, however, its contribution to cell cohesion in ESCC remains to be elucidated. In the present study, using RNA interference (RNAi), the expression of DSC2 was silenced in SHEEC and KYSE510 cells. Hanging drop and fragmentation assays were performed to investigate the role of DSC2 in cell­cell adhesion. Western blot analysis and confocal microscopy were used to analyze the expression and localization of cell adhesion molecules and cytoskeletal arrangement. The results demonstrated that DSC2 knock down by RNAi caused defects in cell­cell adhesion and a concomitant reduction in desmosomal protein expression and adherens junction molecule distribution. A decrease in the expression of DSC2 caused an increase in free γ­catenin levels, thus promoting its recruitment to the adherens junction complex. In addition, the RNAi­mediated inhibition of DSC2 led to keratin intermediate filament retraction and filamentous­actin cytoskeleton rearrangement. Taken together, these data support our previous findings and the proposal that DSC2 may be involved in the regulation of the invasive behavior of cells by a mechanism that controls cell­cell attachment and cytoskeleton rearrangement.

Prognostic significance of desmoglein 2 and desmoglein 3 in esophageal squamous cell carcinoma.

OBJECTIVE: Desmogleins (DSGs) are major members among the desmosomal cadherins critically involved in cell-cell adhesion and the maintenance of normal tissue architecture in epithelia. Reports exploring links of DSG family member expression with cancers are few and vary. The aim of this study was to investigate the ratio of DSG2 and DSG3 mRNA expression in esophageal squamous cell carcinoma (ESCC) tissue to normal tissue (T/N ratio) and evaluate correlations with clinical parameters. METHODS: The mRNA expression of DSGs, as well as γ-catenin and desmoplakin, was detected by real-time quantitative RT-PCR in 85 cases of ESCC tissue specimens. RESULTS: The expression level of DSG3 mRNA was significantly higher than that of DSG2 in ESCC specimens (p = 0.000). DSG3 mRNA expression highly correlated with histological grade (p = 0.009), whereas that of DSG2 did not significantly relate to any clinicopathologic parameter. Kaplan-Meier survival analysis showed that only DSG3 expression had an impact on the survival curve, with negative DSG3 expression indicating worse survival (p = 0.038). Multivariate Cox regression analysis demonstrated DSG3 to be an independent prognostic factor for survival. Furthermore, correlation analysis demonstrated the mRNA level of DSG3 to highly correlate with those of γ-catenin and desmoplakin in ESCC samples (p=0.000), implying that the expression of desmosomal components might be regulated by the same upstream regulatory molecules. CONCLUSIONS: Our findings suggest that DSG3 may be involved in the progression of ESCC and serve as a prognostic marker, while expression of DSG2 cannot be used as a predictor of ESCC patient outcome.