IL-33-expressing microvascular endothelial cells in human esophageal squamous cell carcinoma: Implications for pathological features and prognosis

Accumulating evidence suggests that interleukin (IL)-33 plays a critical role in regulating angiogenesis and cancer progression. In this study, we characterized the pathological importance of IL-33 deployed by tumor microvascular endothelial cells (ECs) in human esophageal squamous cell carcinoma (ESCC). The expression of IL-33 in microvascular ECs in 80 cases of ESCC was examined with immunohistochemistry (IHC) and double immunofluorescence. IHC results showed that strong IL-33-immunoreactivity (IR) in microvessels, which were confirmed to be ECs by double immunofluorescence staining with IL-33/CD31 antibodies. Moreover, high proliferative activity was shown in IL-33-positive ECs, and the IL-33 functional receptor ST2 was expressed in microvascular ECs. Clinicopathological analysis revealed that IL-33-positive microvessel density (MVD) was positively correlated with node involvement in patients with ESCC. A log rank test showed a highly significant inverse correlation between the densities of IL-33-positive MVDs and overall survival rate, and patients with higher IL-33-positive MVDs tended to have a lower survival rate (both p < 0.05). Therefore, we concluded that IL-33 deployed by microvascular ECs correlates with advanced pathological features and the long-term survival rate, which provides new insights into the regulatory mechanisms of tumor angiogenesis in the tumor microenvironment and might serve as a promising target in patients with ESCC.

Identification and detection of plasma extracellular vesicles-derived biomarkers for esophageal squamous cell carcinoma diagnosis

Esophageal cancer is a malignant tumor with two-thirds of patients having a local recurrence or distant metastasis. To date, diagnostic biomarkers with high sensitivity and specificity are lacking. Extracellular vesicles (EVs) have shown their potential values as disease biomarkers as they carry specific proteins and RNAs derived from cancer cells. In this study, we investigate ESCC precision diagnostics from the insights of circulating EVs, and integrate the ultrafast EV isolation approach (EXODUS) and ELISA for fast detection and screening of ESCC patients. First, we isolate and characterize the high-purity plasma EVs with EXODUS and identify 401 proteins and 372 proteins from ESCC patient and healthy individuals, respectively. Further looking into the differentially expressed proteins (DEPs) of ESCC patients and enriched KEGG pathways, we discover EV-CD14 as a potential diagnostic biomarker for ESCC, which has been further validated as a significantly differentially expressed protein by Western Blot and immunogold labelling TEM. For fast screening and detection of ESCC towards clinical applications, we apply ELISA method to diagnose ESCC from 60 clinical samples based on circulating EV-CD14, which shows a high AUC value up to 96.0% for detection of ESCC in a test set (30 samples), and displays a high accuracy rate up to 90% for prediction of ESCC in a screening test (30 samples). Our results suggest that the circulating EV-CD14 may highly be related to the initiation and progression of ESCC, providing a novel method for the diagnosis and prognosis of ESCC towards clinical translations.

SAMD9 Promotes Postoperative Recurrence of Esophageal Squamous Cell Carcinoma by Stimulating MYH9-Mediated GSK3β/β-Catenin Signaling

Recurrence is a challenge to survival after the initial treatment of esophageal squamous cell carcinoma (ESCC). But, its mechanism remains elusive and there are currently no biomarkers to predict postoperative recurrence. Here, the possibility of sterile alpha motif domain-containing protein 9 (SAMD9) as a predictor of postoperative recurrence of ESCC is evaluated and the molecular mechanisms by which SAMD9 promotes ESCC recurrence are elucidated. The authors found that the high level of SAMD9 is correlated with postoperative recurrence and poor prognosis of ESCC. Overexpression of SAMD9 promotes tumor stemness, angiogenesis, and EMT, while downregulation of SAMD9 reduced these phenotypes. Mechanistically, it is found that SAMD9 stimulated ubiquitination-mediated glycogen synthase kinase-3 beta (GSK-3β) degradation by interaction with myosin-9 (MYH9) and TNF receptor-associated factor 6 (TRAF6), which in turn activated Wnt/β-catenin pathway. Further, the authors demonstrated that silencing SAMD9 inhibited lung metastasis and tumor formation in vivo. Finally, the authors found that silencing MYH9 or β-catenin, or overexpressing GSK-3β inhibited SAMD9-stimulated ESCC cell stemness, EMT, angiogenesis, metastasis, and tumorigenicity. Together, the findings indicate that the SAMD9/MYH9/GSK3β/β-catenin axis promotes ESCC postoperative recurrence and that SAMD9 is a crucial target for ESCC therapy. Additionally, SAMD9 has the potential as a predictor of postoperative recurrence in ESCC.

ANXA2 as a novel substrate of FBXW7 promoting esophageal squamous cell carcinoma via ERK phosphorylation

Our recent study suggests that FBXW7 loss of function plays a critical function in esophageal cancer. However, the mechanism of FBXW7 in promoting esophageal cancer is still unclear. Here, we explored the interaction protein of FBXW7 by screening of GST-pulldown and LC-MS/MS analysis in esophageal squamous cell carcinoma (ESCC) and identified ANXA2 as a potential target of FBXW7. FBXW7 loss of function could restore the expression of ANXA2 and promote the malignant biological characteristics of ESCC cells in vitro. Up-regulation of ANXA2 enhances the ERK pathway in ESCC. Furthermore, the 23rd tyrosine residue of ANXA2, phosphorylated by SRC, was regarded as playing important roles in the FBXW7-related degradation system. In clinical samples, we found that ANXA2 had high expression in ESCC tissues. High ANXA2 was associated with poor tumor staging. More importantly, we designed a combination regimen including SCH779284, a clinical ERK inhibitor against the phosphorylation of EKR and siRNA targeting ANXA2 by intratumor injection, and it produced potent inhibitory effects on the growth of xenograft tumors in vivo. In conclusion, this study provided evidence that FBXW7 loss of function could promote esophageal cancer through ANXA2 overexpression, and this novel regulation pathway may be used as an efficient target for ESCC treatment.

Long non-coding RNA NCK1-AS1 functions as a ceRNA to regulate cell viability and invasion in esophageal squamous cell carcinoma via microRNA-133b/ENPEP axis

This study is designed to explore the role of long non-coding RNAs (lncRNAs) NCK1-AS1 in proliferative and invasive activities of esophageal squamous cell carcinoma (ESCC) cells by binding to microRNA-133b (miR-133b) to regulate ENPEP. Differentially expressed lncRNAs, miRs, genes and their targeting relationships were screened on ESCC-related gene expression datasets GSE17351 and GSE6188. The targeting relationships among NCK1-AS1, miR-133b, and ENPEP were verified using functional assays. Loss- and gain- of function assays were carried out to examine the roles of NCK1-AS1, miR-133b, and ENPEP in ESCC cell proliferative, invasive, migrative and apoptotic abilities as well as tumorigenesis in vivo. Elevated NCK1-AS1 and ENPEP but reduced miR-133b expression were found in ESCC. NCK1-AS1 knockdown or miR-133b overexpression inhibited the malignant properties of ESCC cells as well as tumorigenesis in vivo. NCK1-AS1 regulated the ENPEP expression by competitively binding to miR-133b. ENPEP overexpression reversed inhibition of NCK1-AS1 knockdown on the function of ESCC cells. This study provides evidence that silencing NCK1-AS1 inhibits expression of ENPEP by sponging miR-133b, thereby suppressing ESCC.

EZH2 deregulates BMP, Hedgehog, and Hippo cell signaling pathways in esophageal squamous cell carcinoma

PURPOSE

Cell signaling pathways play central roles in cellular stemness state, and aberrant activation of these cascades is attributed to the severity of esophageal squamous cell carcinoma (ESCC). In this study, we aimed to determine the potential impact of enhancer of zeste homolog 2 (EZH2) gene on different cell signaling pathways including bone morphogenesis protein (BMP), Hedgehog, and Hippo in ESCC, and to illuminate EZH2-mediated gene regulatory networks in this aggressive malignancy.

MATERIALS AND METHODS

EZH2 silencing was performed in two ESCC lines, KYSE-30 and YM-1, followed by gene expression analysis of BMP, Hedgehog, and Hippo signaling using RT-qPCR. EZH2 enforced expression was induced in both cell lines and gene expression of the pathways was evaluated in parallel. The contribution of EZH2 in epithelial-mesenchymal transition (EMT) and cell migration were also evaluated.

RESULTS

EZH2 downregulation decreased expression of the vital components of the Hedgehog and Hippo signaling, while EZH2 upregulation significantly increased its levels in both ESCC cell lines. The expression of BMP target genes was either reduced in EZH2-expressing cells or increased in EZH2-silencing cells. Enforced expression of EZH2 stimulated downregulation of epithelial markers and upregulation of mesenchymal markers in KYSE-30 and YM-1 ​cells. Significant downregulation of mesenchymal markers was detected following the silencing of EZH2 in the cells. Knocking down EZH2 decreased migration, while enforced expression of EZH2 increased migration in both ESCC lines.

CONCLUSIONS

These results may support the promoting role of EZH2 in ESCC tumorigenesis through the recruitment of important cell signaling pathways.

A reliable mouse model of liver and lung metastasis by injecting esophageal cancer stem cells (CSCs) through tail-vein injection

BACKGROUND

Esophageal Squamous Cell Carcinoma (ESCC) is a highly aggressive tumor with increased metastatic potential. Recent evidence suggests that esophageal CSCs have a crucial role in tumor initiation, progression, and resistance to conventional anti-cancer therapies. The study aimed to develop mouse model to mimic the late steps of the metastasis process using a tail-vein injection of esophageal CSCs.

METHODS AND RESULTS

The sphere formation assay was used to enrich CSCs. For analysis of tumorigenicity, YM-1 adherent cells and enriched CSCs were injected subcutaneously into dorsal flank of nude mice. The expression of SLUG, E-cad, and CTHRC1 genes was examined by Real-Time qRT-PCR and immunohistochemistry (IHC) methods. To assess the metastatic potential of adherent YM-1 cells and their enriched CSCs, we injected the cells into the tail vein of nude mice. Our findings showed the up-regulation of SLUG and down-regulation of E-cad in the esophageal CSC-derived tumors (ECSCTs) compared to adherent cells-derived tumors. There was no statistically significant difference between CTHRC1 gene expressions in both groups of tumors. IHC staining confirmed the higher expression of SLUG protein in ECSCTs compared to adherent cell-derived tumors. Enriched CSCs were able to metastasize to the lungs and livers after three months, but, metastasis of adherent cells wasn't observed.

CONCLUSION

Our study showed esophageal CSCs injected through the tail-vein injection can migrate and metastasize to the lung and liver after three months. The developed metastatic mouse model can be a valuable and relevant model to investigate the molecular and cellular mechanisms of metastasis and develop successful targeted therapies against ESCC. The present study is one of the few studies that investigate the metastasis of esophageal cancer stem cells (ESCC type) through injection into the tail vein of nude mice.

HPV 16 E6 promotes growth and metastasis of esophageal squamous cell carcinoma cells in vitro

BACKGROUND

Esophageal squamous cell carcinoma (ESCC) is one of the most lethal malignancies worldwide. Increasing evidence suggests that human papillomavirus (HPV) infection may be associated with the etiology of ESCC. However, the precise role of HPV in ESCC remains unclear.

METHODS AND RESULTS

Proliferation and apoptosis of ESCC cells upon infection with HPV16 E6 were detected using CCK-8 assays and Western blot analyses. The migration rate was measured with a wound healing assay, and a Transwell Matrigel invasion assay was used to detect the invasive ability. RT-qPCR was performed to detect the expression of E6AP, p53, and miR-34a. The proliferation rates were significantly higher in HPV16E6-transfected cell groups compared with the negative control groups. Bax protein expression was downregulated in HPV16E6-treated groups compared to the controls. The wound healing and Transwell Matrigel invasion assays indicated that HPV16 E6 infection could increase ESCC cell migration and invasion. Furthermore, E6AP, p53 and miR-34a expression were decreased in HPV16 E6-transfected cell lines.

CONCLUSION

Our results not only provide evidence that HPV16 E6 promotes cell proliferation, migration, and invasion in ESCC, but also suggests a correlation between HPV infection and E6AP, p53 and miR-34a expression. Consequently, HPV16 E6 may play an important role in ESCC development.

N-nitrosamines-mediated downregulation of LncRNA-UCA1 induces carcinogenesis of esophageal squamous by regulating the alternative splicing of FGFR2

Concerns are raised over the risk to digestive system's tumors from the N-nitrosamines (NAs) exposure in drinking water. Albeit considerable studies are conducted to explore the underlying mechanism responsible for NAs-induced esophageal squamous cell carcinoma (ESCC), the exact molecular mechanisms remain largely unknown, especially at the epigenetic regulation level. In this study, it is revealed that the urinary concentration of N-Nitrosodiethylamine is higher in high incidence area of ESCC, and the lncRNA-UCA1(UCA1) is significantly decreased in ESCC tissues. In vitro and in vivo experiments further show that UCA1 is involved in the malignant transformation of Het-1A cells and precancerous lesions of the rat esophagus induced by N-nitrosomethylbenzylamine (NMBzA). Functional gain and loss experiments verify UCA1 can affect the proliferation, migration, and invasion of ESCC cells in vitro and in vivo. Mechanically, through binding to heterogeneous nuclear ribonucleoprotein F (hnRNP F) protein, UCA1 regulates alternative splicing of fibroblast growth factor receptor 2 (FGFR2), which promotes the FGFR2IIIb isoform switching to FGFR2 IIIc isoform, and the latter activates epithelial-mesenchymal transition via PI3K-AKT signaling pathways impacting tumorigenesis. Therefore, NAs-mediated downregulation of UCA1 promotes ESCC progression through targeting hnRNP F/FGFR2/PI3k-AKT axis, which provides a new chemical carcinogenic target and establishes a previously unknown mechanism for NAs-induced ESCC.

TIGIT blockade enhances tumor response to radiotherapy via a CD103 + dendritic cell-dependent mechanism

Blockade of the T cell immunoreceptor with the immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domain (TIGIT) can enhance innate and adaptive tumor immunity and radiotherapy (RT) can enhance anti-tumor immunity. However, our data suggest that TIGIT-mediated immune suppression may be an impediment to such goals. Herein, we report on the synergistic effects of RT combined with anti-TIGIT therapy and the mechanism of their interaction. Treatment efficacy was assessed by measuring primary and secondary tumor growth, survival, and immune memory capacity. The function of CD103 + dendritic cells (DCs) under the combined treatment was assessed in wild-type and BATF3-deficient (BATF3^-/-) mice. FMS-like tyrosine kinase 3 ligand (Flt3L) was used to confirm the role of CD103 + DCs in RT combined with anti-TIGIT therapy. TIGIT was upregulated in immune cells following RT in both esophageal squamous cell carcinoma patients and mouse models. Administration of the anti-TIGIT antibody enhanced the efficacy of RT through a CD8 + T cell-dependent mechanism. It was observed that RT and the anti-TIGIT antibody synergistically enhanced the accumulation of tumor-infiltrating DCs, which activated CD8 + T cells. The efficacy of the combination therapy was negated in the BATF3^-/- mouse model. CD103 + DCs were required to promote the anti-tumor effects of combination therapy. Additionally, Flt3L therapy enhanced tumor response to RT combined with TIGIT blockade. Our study demonstrated TIGIT blockade can synergistically enhance anti-tumor T cell responses to RT via CD8 + T cells (dependent on CD103 + DCs), suggesting the clinical potential of targeting the TIGIT pathway and expanding CD103 + DCs in RT.

[Identification of ion channel/transporter expression profiles in digestive cancer stem cells for novel targeting therapy]

Recent evidence suggests that the targeting of membrane transporters specifically activated in cancer stem cells (CSCs) is an important strategy for cancer therapy. The objectives of the present study were to investigate the ion channel expression profiles in digestive CSCs. Cells strongly expressing CSC markers, such as ALDH1A1 and CD44, were separated from the human esophageal squamous cell carcinoma, gastric cancer, and pancreatic cancer cell lines using fluorescence-activated cell sorting, and CSCs were identified based on tumorsphere formation. Messenger RNA levels of CSC markers were higher in CSCs than in non-CSCs. These CSCs also exhibited resistance to anticancer agents. The microarray analysis revealed that the expression of transient receptor potential vanilloid 2 (TRPV2), voltage-gated calcium channels (VGCCs), and voltage-gated potassium channels (VGKCs) were upregulated in esophageal, gastric, and pancreatic CSCs, respectively, compared with non-CSCs. The TRPV2 inhibitor tranilast, VGCCs inhibitors amlodipine and verapamil, and VGKC inhibitor 4-aminopyridine exhibited greater cytotoxicity in CSCs compared with non-CSCs, and their inhibitory effects were also confirmed in a xenograft model in nude mice. Taking these results, phase I/II study to investigate clinical safety and efficacy of neoadjuvant combination chemotherapy of tranilast in advanced esophageal squamous cell carcinoma (TNAC study) is ongoing. These researches identified a role of ion channels in the persistence of CSCs and suggested that their inhibitors may have potential as a therapeutic agent for digestive cancers.

HOXD11 upregulates JAM-A and exerts oncogenic properties via NF-κB signaling pathway in esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is a tumor with high incidence and poor prognosis in developing countries. Junctional adhesion molecule A (JAM-A, also known as F11R) affects numerous biological processes, which is a vital regulator of the development of malignant tumors. However, its exact role and underlying mechanism in ESCC remain obscure. Our present study demonstrated that JAM-A was upregulated in ESCC tissues and cell lines by RNA sequencing and immunohistochemistry (IHC). JAM-A knockdown significantly suppressed the proliferation of the ESCC cells, induced cell cycle arrest at the G1 and promoted apoptosis, and suppressed the ability of invasion and migration in vivo and in vitro. Mechanistically, JAM-A may activate the NF-κB signaling pathway to regulate malignant behavior of ESCC. Further research showed that Homeobox D11 (HOXD11) could directly regulate JAM-A transcription by binding to specific sequences of JAM-A promoter region, thereby activating NF-κB signaling pathway to regulate malignant behavior of ESCC. Functional experiments indicated that HOXD11 could exert an oncogenic role in ESCC. Collectively, our findings support the hypothesis that the HOXD11/JAM-A/NF-κB signal axis plays a role in regulating malignant behavior in ESCC patients, highlighting its potential therapeutic value for ESCC.

TWIST1 Plays Role in Expression of Stemness State Markers in ESCC

BACKGROUND

Stemness markers play critical roles in the maintenance of key properties of embryonic stem cells (ESCs), including the pluripotency, stemness state, and self-renewal capacities, as well as cell fate decision. Some of these features are present in cancer stem cells (CSCs). TWIST1, as a bHLH transcription factor oncogene, is involved in the epithelial-mesenchymal transition (EMT) process in both embryonic and cancer development. Our aim in this study was to investigate the functional correlation between TWIST1 and the involved genes in the process of CSCs self-renewal in human esophageal squamous cell carcinoma (ESCC) line KYSE-30.

METHODS

TWIST1 overexpression was enforced in the ESCC KYSE-30 cells using retroviral vector containing the specific pruf-IRES-GFP-hTWIST1 sequence. Following RNA extraction and cDNA synthesis, the mRNA expression profile of TWIST1 and the stem cell markers, including BMI1, CRIPTO1, DPPA2, KLF4, SOX2, NANOG, and MSI1, were assessed using relative comparative real-time PCR.

RESULTS

Ectopic expression of TWIST1 in KYSE-30 cells resulted in an increased expression of TWIST1 compared to control GFP cells by nearly 9-fold. Transduction of TWIST1-retroviral particles caused a significant enhancement in BMI1, CRIPTO1, DPPA2, KLF4, and SOX2 mRNA expression, approximately 4.5-, 3.2-, 5.5-, 3.5-, and 3.7-folds, respectively, whereas this increased TWIST1 expression caused no change in the mRNA expression of NANOG and MSI1 genes.

CONCLUSIONS

TWIST1 gene ectopic expression in KYSE-30 cells enhanced the level of cancer stem cell markers' mRNA expression. These results may emphasize the role of TWIST1 in the self-renewal process and may corroborate the involvement of TWIST1 in the stemness state capacity of ESCC cell line KYSE-30, as well as its potential as a therapeutic target.

A novel synthetic chalcone derivative, 2,4,6-trimethoxy-4'-nitrochalcone (Ch-19), exerted anti-tumor effects through stimulating ROS accumulation and inducing apoptosis in esophageal cancer cells

Esophageal cancer has always been associated with poor prognosis and a low five-year survival rate. Chalcone, a flavonoid family member, has shown anti-tumor property in several types of cancer. However, few studies reported the potency and mechanisms of action of synthetic Chalcone derivatives against esophageal squamous cell carcinoma. In this study, we designed and synthesized a series of novel chalcone analogs and Ch-19 was selected for its superior anti-tumor potency. Results indicated that Ch-19 shows a dose- and time-dependent anti-tumor activity in both KYSE-450 and Eca-109 esophageal cancer cells. Moreover, treatment of Ch-19 resulted in the regression of KYSE-450 tumor xenografts in nude mice. Furthermore, we investigated the potential mechanism involved in the effective anti-tumor effects of Ch-19. As a result, we observed that Ch-19 treatment promoted ROS accumulation and caused G2/M phase arrest in both Eca-109 and KYSE-450 cancer cell lines, thereby resulting in cell apoptosis. Taken together, our study provided a novel synthetic chalcone derivative as a potential anti-tumor therapeutic candidate for treating esophageal cancer.

Anti-tumour effects of a macrolide analog F806 in oesophageal squamous cell carcinoma cells by targeting and promoting GLUT1 autolysosomal degradation

Cancer cells are characterized by altered energetic metabolism with increasing glucose uptake. F806, a 16-membered macrodiolide analogue, has anti-tumour effects on oesophageal squamous cell carcinoma (ESCC) cells. However, its precise anti-tumour mechanism remains unclear. Here, metascape analysis of our previous quantitative proteomics data showed that F806 induced glucose starvation response and inhibited energy production in ESCC cells. The reduced glucose uptake and ATP production were further validated by the fluorescent methods, using glucose-conjugated bioprobe Glu-1-O-DCSN, and the bioluminescent methods, respectively. Consistently, under F806 treatment the AMP-activated protein kinase signalling was activated, and autophagy flux was promoted and more autophagosomes were formed. Moreover, live-cell imaging and immunofluorescence analysis showed that F806 induced GLUT1 plasma membrane dissociation and promoted its internalization and autolysosome accumulation and lysosome degradation. Furthermore, molecular docking studies demonstrated that F806 bound to GLUT1 with a comparable binding energy to that of GLUT1's direct interacting inhibitor cytochalasin B. Amino acid mutation was used to test which residues of GLUT1 may participate in F806 mediated-GLUT1 internalization and degradation, and results showed that Thr137, Asn411 and Trp388 were required for GLUT1 internalization and degradation, respectively. Taken together, these findings shed light on a novel anti-tumour mechanism of F806 by targeting and promoting GLUT1 internalization and further autolysosomal degradation.

Transcription factor NFE2L3 promotes the proliferation of esophageal squamous cell carcinoma cells and causes radiotherapy resistance by regulating IL-6

OBJECTIVE

To scrutinize the impact of overexpression and interference of NFE2L3 on radiosensitivity of esophageal squamous cell carcinoma cells (ESCC) and its downstream mechanism and to assess whether NFE2L3 expression alters in vivo radiosensitivity of ESCC by developing a subcutaneous tumor model in mice.

METHODS

Through RNA-Seq, we compared the differentially expressed genes between the ECA-109R cell line and its parent ECA-109 cell line. The differentially expressed genes were selected and verified by qRT-PCR. Transfection of ESCC cell lines with NFE2L3 inhibitor or mimic lentivirus constructs was done to study the activity of NFE2L3. To assess the effect of NFE2L3 on cellular growth and proliferation, clonogenic survival assay, EdU incorporation assay, and CCK-8 assay were done after irradiation. To probe how many irradiated DNA double-strand breaks were produced, the corresponding intensity of γ-H2AX foci were detected by immunofluorescence. Apoptotic cells were assayed by flow cytometry assay after irradiation; To investigate the downstream genes of NFE2L3, we knocked NFE2L3, and RNA-Seq was used to find out the downstream genes. qRT-PCR and western blot ensued to score associated protein profiles. The in vivo ESCC cell radiosensitivity was scrutinized by nude mouse xenograft models.

RESULTS

The differential genes between ECA-109R cells and its parent ECA-109 cells were compared by qRT-PCR to unveil a significant increase in NFE2L3 expression. Functional analysis indicated that NFE2L3 increased radioresistance in ESCC cells. Then, through high-throughput sequencing and bioinformatics analysis, IL-6 was found to be a hub gene that played a role downstream of NFE2L3 and was verified by qRT-PCR, western blot, and double luciferase reporter gene experiment. NFE2L3 could regulate ESCC cell radiosensitivity via the IL-6-STAT3 signaling pathway, and downregulation of IL-6 expression could reverse the effects of highly expressed NFE2L3. In vivo tumor xenograft experiments confirmed that NFE2L3 affects the sensitivity to radiation therapy.

CONCLUSION

NFE2L3 can affect the radiosensitivity of ESCC cells through IL-6 transcription and IL-6/STAT3 signaling pathway. This makes NFE2L3 a putative target to regulate ESCC cell radiosensitivity.

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.

Inactivation of Hippo pathway characterizes a poor-prognosis subtype of esophageal cancer

Identification of molecular subtypes that reflect different prognoses and treatment responses, especially immune checkpoint inhibitors (ICIs) in esophageal squamous cell carcinoma (ESCC), is essential for treatment decisions. We performed targeted sequencing in 201 patients with ESCC to discover genetic subtypes and validate our findings via multiple data sets. We identified 3 driver genes (FCGBP, GRIN2B, and FRY), and recurrent truncating mutations in FRY impaired its tumor-suppressive function and promoted tumor proliferation. A 3-gene mutation signature (FAT1, FAT3, and FRY) recognized a molecular subtype named “FAT/FRY” with frequent Hippo pathway–related mutations. In multiple ESCC cohorts, the patients with the FAT/FRY subtype had poorer prognosis than did patients in the WT group. Transcriptome analysis indicated that the FAT/FRY subtype was characterized by inactivation of the Hippo pathway, hypoxia, chemoresistance, higher infiltration of CD8⁺ T cells and activated DCs, and a transcriptome similar to that of cancer responders. Furthermore, the 3-gene signature predicted better survival for patients treated with ICIs, partially explained by its positive correlation with the tumor mutation burden and neoantigen burden. The 3-gene signature is a biomarker to recognize the FAT/FRY molecular subtype, evaluate prognosis, and select potential beneficiaries of ICIs in ESCC.

[Effects of TOFA on growth of Eca109 and KYSE-450 cells in human esophageal squamous cell carcinoma]

Objective: To investigate the effects of 5-tetradecanoxy 2-furanic acid (TOFA) on cell proliferation, cell cycle and apoptosis of esophageal squamous cell carcinoma (ESCC) cells. Methods: Eca-109 cells and KYSE-450 cells were divided into control group (DMSO) and experimental group (TOFA), respectively. The cells (4×10³ cells/100 μl) were inoculated into 96-well plates with 5 multiple wells at each concentration. After 24 h culture, cells were treated with DMSO or different concentrations (1, 3, 5, 10 μg/ ml) of TOFA for 24, 48 and 72 h. Cell proliferation was detected by MTT, cell cycle and apoptosis were detected by flow cytometry, the expression levels of p21 and Cleaved caspase-3 and modification levels of p-Akt, p-mTOR and p-4EBP1 were detected by Western blot, and intracellular free fatty acids were detected by special kits. Results: MTT results showed that TOFA inhibited the proliferation of Eca109 and KYSE-450 cells in a concentration and time dependent manner (all P<0.05), with IC₅₀ of 4.65 μg/ml and 3.93 μg/ml for 48 h, respectively. Flow cytometry results showed that compared with DMSO group, the percentage of cells in G2/M phase was increased and the apoptosis rate was increased in the experimental group. Western blotting results showed that compared with DMSO group, p21 and Cleaved caspase-3 protein expression levels were up-regulated, and p-AKT, p-mTOR and p-4EBP1 protein expression levels were down-regulated (all P<0.05). Conclusion: TOFA inhibits the proliferation, blocks the cycle progression and promotes apoptosis of ESCC, the mechanism may be related to the AKT/mTOR/4EBP1 signaling pathway.

Baicalein Inhibits the Progression and Promotes Radiosensitivity of Esophageal Squamous Cell Carcinoma by Targeting HIF-1A

Purpose

To explore the mechanism of the effect of baicalein on radioresistance of esophageal cancer, and to provide ideas for the treatment of patients with poor radiotherapy effect of esophageal cancer.

Methods

The glycolytic rate assay kit was used to detect the changes in glycolytic metabolism in esophageal cancer cells after treatment with baicalein, and mass spectrometry was used to detect whether baicalein could affect the level of glycolysis-related metabolites in esophageal cancer cells. The binding of baicalein to the target protein was simulated by molecular docking technique, the protein expression level was detected by Western Blot, and the changes in the cell cycle were detected by flow cytometry.

Results

Radiation combined with baicalein could significantly inhibit the proliferation and migration of esophageal cancer cells compared with that of 6 Gy rays alone. The results of the glycolytic rate assay showed that baicalein could inhibit the glycolysis of esophageal cancer cells. Metabonomic studies showed that baicalein could affect the expression levels of glycolysis-related metabolites. The results of network pharmacology showed that baicalein could target several key glycolysis enzymes and glycolysis-related proteins, such as HIF-1A. The results of the WB experiment showed that glycolysis-related proteins and cycle-related proteins were down-regulated after baicalein treatment.

Conclusion

The main mechanism of baicalein inhibiting radiation resistance of esophageal cancer cells is that targeting HIF-1A protein regulates glucose metabolism and then regulates Cyclin D1/CDK4 axis to change the cell cycle.

Lipid metabolism-related lncRNA SLC25A21-AS1 promotes the progression of oesophageal squamous cell carcinoma by regulating the NPM1/c-Myc axis and SLC25A21 expression

BACKGROUND

Obesity alters metabolic microenvironment and is thus associated with several tumours. The aim of the present study was to investigate the role, molecular mechanism of action, and potential clinical value of lipid metabolism-related long non-coding RNA (lncRNA) SLC25A21-AS1 in oesophageal squamous cell carcinoma (ESCC).

METHODS

A high-fat diets (HFDs)-induced obesity nude mouse model was established, and targeted metabolomics analysis was used to identify critical medium-long chain fatty acids influencing the growth of ESCC cells. Transcriptomic analysis of public dataset GSE53625 confirmed that lncRNA SLC25A21-AS1 was a lipid metabolism-related lncRNA. The biological function of lncRNA SLC25A21-AS1 in ESCC was investigated both in vivo and in vitro. Chromatin immunoprecipitation(ChIP)assay, RNA-pull down, mass spectrometry, co-IP, and RNA IP(RIP) were performed to explore the molecular mechanism. Finally, an ESCC cDNA microarray was used to determine the clinical prognostic value of SLC25A21-AS1 by RT-qPCR.

RESULTS

Palmitic acid (PA) is an important fatty acid component of HFD and had an inhibitory effect on ESCC cell lines. LncRNA SLC25A21-AS1 expression was downregulated by PA and associated with the proliferation and migration of ESCC cells in vitro and in vivo. Mechanistically, SLC25A21-AS1 interacted with nucleophosmin-1 (NPM1) protein to promote the downstream gene transcription of the c-Myc in the nucleus. In the cytoplasm, SLC25A21-AS1 maintained the stability of SLC25A21 mRNA and reduced the intracellular NAD+ /NADH ratio by influencing tryptophan catabolism. Finally, we demonstrated that high expression of SLC25A21-AS1 promoted resistance to cisplatin-induced apoptosis and was correlated with poor tumour grade and overall survival.

CONCLUSIONS

HFD/PA has an inhibitory effect on ESCC cells and SLC25A21-AS1 expression. SLC25A21-AS1 promotes the proliferation and migration of ESCC cells by regulating the NPM1/c-Myc axis and SLC25A21 expression. In addition, lncRNA SLC25A21-AS1 may serve as a favourable prognostic biomarker and a potential therapeutic target for ESCC.

NEDD4L inhibits cell viability, cell cycle progression, and glutamine metabolism in esophageal squamous cell carcinoma via ubiquitination of c-Myc

Esophageal squamous cell carcinoma (ESCC) is a common subtype of esophageal cancer with high incidence. Surgery remains the main strategy for treatment of ESCC at early stage. However, the treatment outcome is unsatisfactory. Therefore, finding new therapeutics is of great importance. In the present study, we measured the level of NEDD4L, an ubiquitin protein ligase, in clinical samples and investigated the effects of NEDD4L on cell viability, cell cycle progression, and glutamine metabolism in TE14 cells determined by CCK-8 assay, flow cytometry and biochemical analysis, respectively. The results show that NEDD4L is significantly decreased in ESCC specimens, and its decreased expression is associated with a poor clinical outcome. Overexpression of NEDD4L significantly inhibits cell viability, cell cycle progression, and glutamine metabolism in TE14 cells. Mechanistic study indicates that NEDD4L regulates tumor progression through ubiquitination of c-Myc and modulation of glutamine metabolism. NEDD4L inhibits cell viability, cell cycle progression, and glutamine metabolism in ESCC by ubiquitination of c-Myc to decrease the expressions of GLS1 and SLC1A5. Our findings highlight the importance of NEDD4L/c-Myc signaling in ESCC.

Blocking STAT3 signaling augments MEK/ERK inhibitor efficacy in esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is one of the world's leading causes of death, and its primary clinical therapy relies on surgical resection, chemotherapy, radiotherapy, and chemoradiotherapy. Although the genomic features and clinical significance of ESCC have been identified, the outcomes of targeted therapies are still unsatisfactory. Here, we demonstrate that mitogen-activated protein kinase (MAPK) signaling is highly activated and associated with poor prognosis in patients with ESCC. Mitogen-activated protein kinase kinase (MEK) inhibitors efficiently blocked the phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2) in ESCC, while signal transducer and activator of transcription 3 (STAT3) signaling was rapidly activated. Combined STAT3 inhibition prevented the emergence of resistance and enhanced MEK inhibitor-induced cell cycle arrest and senescence in vitro and in vivo. Mechanistic studies revealed that the suppressor of cytokine signaling 3 (SOCS3) was downregulated, resulting in an increase in STAT3 phosphorylation in MEK-inhibited cells. Furthermore, chromatin immunoprecipitation showed that ELK1, which was activated by MEK/ERK signaling, induced SOCS3 transcription. These data suggest that the development of combined MEK and STAT3 inhibition could be a useful strategy in ESCC targeted therapy.

Potential Chemotherapeutic Effect of Selenium for Improved Canceration of Esophageal Cancer

Esophageal squamous cell carcinoma is the most common type of esophageal cancer and accounts for 5% of malignant tumor deaths. Recent research suggests that chronic inflammation and DNA damage may drive the onset of esophageal squamous cell carcinoma, implying that lowering chronic inflammation and DNA damage compounds may provide chemo-prevention. According to epidemiological and experimental evidence, selenium is linked to a lower risk of several malignancies, including esophageal squamous cell carcinoma. However, its exact mechanism is still unclear. In the present study, we used cell lines and a 4-NQO mice model to explore the anti-cancer mechanism of four types of selenium. Our findings indicated that selenium inhibited the proliferation, colony formation, and ROS level of ESCC cell lines in a time-dependent manner. Intriguingly, selenium treatment impeded 4-NQO-induced high-grade intraepithelial neoplasia and reduced the number of positive inflammatory cells by preserving DNA from oxidative damage. In addition, selenium significantly decreased the expression of Ki-67 and induced apoptosis. This study demonstrates that selenium has a significant chemo-preventive effect on ESCC by reducing high-grade dysplasia to low-grade dysplasia. For the first time, selenium was shown to slow down the progression of esophageal cancer by lowering inflammation and oxidative DNA damage.

TRIP13 Induces Nedaplatin Resistance in Esophageal Squamous Cell Carcinoma by Enhancing Repair of DNA Damage and Inhibiting Apoptosis

Thyroid hormone receptor interactor 13 (TRIP13) plays a crucial role in poor prognosis and chemotherapy resistance of cancer patients. This present study is aimed at investigating the role of high expression of TRIP13 inducing nedaplatin (NDP) resistance in esophageal squamous cell carcinoma (ESCC) cells. High expression of TRIP13 promoted the proliferation and migration of ESCC cells performed by MTS assay, colony formation assay, wound healing assay, and transwell assay. High TRIP13 expression induced NDP resistance to ESCC based on the cell proliferation promoting/inhibition rate and cell migration promoting/inhibition rate analysis, flow cytometry assay of apoptotic subpopulations with a combination of Annexin V-FITC and propidium iodide, and Western blot analysis downregulating cleaved PARP, γH2A.X, cleaved caspase-3, and Bax and upregulating Bcl-2 expression. This study indicated that high expression of TRIP13 promoted proliferation and migration of ESCC cells and induced NDP resistance via enhancing repair of DNA damage and inhibiting apoptosis. This will provide a preliminary reference for the clinical use of NDP in ESCC treatment.