ESCC Cell Research Articles

Aspirin enhances the therapeutic efficacy of cisplatin in oesophageal squamous cell carcinoma by inhibition of putative cancer stem cells

BackgroundCancer stem cells (CSCs) are related to the patient’s prognosis, recurrence and therapy resistance in oesophageal squamous cell carcinoma (ESCC). Although increasing evidence suggests that aspirin (acetylsalicylic acid, ASA) could lower the incidence and improve the prognosis of ESCC, the mechanism(s) remains to be fully understood.MethodsWe investigated the role of ASA in chemotherapy/chemoprevention in human ESCC cell lines and an N-nitrosomethylbenzylamine-induced rat ESCC carcinogenesis model. The effects of combined treatment with ASA/cisplatin on ESCC cell lines were examined in vitro and in vivo. Sphere-forming cells enriched with putative CSCs (pCSCs) were used to investigate the effect of ASA in CSCs. Assay for Transposase-Accessible Chromatin with high-throughput sequencing (ATAC-seq) was performed to determine the alterations in chromatin accessibility caused by ASA in ESCC cells.ResultsASA inhibits the CSC properties and enhances cisplatin treatment in human ESCC cells. ATAC-seq indicates that ASA treatment results in remarkable epigenetic alterations on chromatin in ESCC cells, especially their pCSCs, through the modification of histone acetylation levels. The epigenetic changes activate Bim expression and promote cell death in CSCs of ESCC. Furthermore, ASA prevents the carcinogenesis of NMBzA-induced ESCC in the rat model.ConclusionsASA could be a potential chemotherapeutic adjuvant and chemopreventive drug for ESCC treatment.

LINC00261 Suppresses Cisplatin Resistance of Esophageal Squamous Cell Carcinoma Through miR-545-3p/MT1M Axis.

To improve the survival rate and cure rate of patients, it is necessary to find a new treatment scheme according to the molecular composition of (ESCC) in esophageal squamous cell carcinoma. Long non-coding RNAs (lncRNAs) regulate the progression of ESCC by various pathophysiological pathways. We explored the possible function of the lncRNA LINC00261 (LINC00261) on cisplatin (DDP) resistance of ESCC and its relative molecular mechanisms. In the study, we found that LINC00261 was downregulated in ESCC tissues, cell lines, and DDP-resistant ESCC patients. Besides, overexpression of LINC00261 not only inhibited cell proliferation, and DDP resistance but also promotes cell apoptosis. Further mechanistic research showed that LINC00261 sponged miR-545-3p which was negatively correlated with the expression of LINC00261. In addition, functional experiments revealed that upregulation of miR-766-5p promoted proliferation and enhanced DDP resistance. Subsequently, MT1M was testified to be the downstream target gene of miR-545-3p. Rescue experiments revealed that overexpression of MT1M largely restores miR-545-3p mimics-mediated function on ESCC progression. Our results demonstrate that the LINC00261 suppressed the DDP resistance of ESCC through miR-545-3p/MT1M axis.

Abstract 3149: Investigation of the potential therapeutic value of CAF-derived milk fat globule-EGF factor 8 protein (MFG-E8) in esophageal squamous cell carcinoma

Abstract The physiological state of the tumor microenvironment (TME) is closely linked with tumorigenesis. RNA sequencing data from our lab showed a broad range of dysregulated genes between ESCC isolated CAFs and paired peripheral blood isolated Fbcs. Among the 2347 up-regulated genes, we found the GO analysis is many focused in extracellular matrix and the top 4 GO terms enriched in cell development and adhesion. Due to this, enriched CAF-secreted extarcellular proteins attracts our attention. MFG-E8 is highly expressed secreted protein in CAFs but low expressed in tumor cells. TCGA database revealed high expression of MFG-E8 is associated with poor overall survival and disease-free survival. In addition, ESCC cell line k410 and K180 with MFG-E8 protein showed a strong ability in cell migration, cell invasion and apoptosis inhibition compared with the PBS group. The further western blot demonstrated MFG-E8 promoted ESCC cell migration and invasion by triggering EMT, and activated an altered akt/stat3 signaling pathway. Moreover, Anti-MFG-E8 antibody effectively reduced tumor size, especially combined with cisplatin. Therefore, MFG-E8 may act as a potential target effective therapeutic strategies. Citation Format: Beilei Liu. Investigation of the potential therapeutic value of CAF-derived milk fat globule-EGF factor 8 protein (MFG-E8) in esophageal squamous cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 3149.

SNORA42 promotes oesophageal squamous cell carcinoma development through triggering the DHX9/p65 axis

Small nucleolar RNAs (snoRNAs) are an important group of non-coding RNAs that have been reported to play a key role in the occurrence and development of various cancers. Here we demonstrate that Small nucleolar RNA 42 (SNORA42) enhanced the proliferation and migration of Oesophageal squamous carcinoma cells (ESCC) via the DHX9/p65 axis. Our results found that SNORA42 was significantly upregulated in ESCC cell lines, tissues and serum of ESCC patients. The high expression level of SNORA42 was positively correlated with malignant characteristics and over survival probability of patients with ESCC. Through in vitro and in vivo approaches, we demonstrated that knockdown of SNORA42 significantly impeded ESCC growth and metastasis whereas overexpression of SNORA42 got opposite effects. Mechanically, SNORA42 promoted DHX9 expression by attenuating DHX9 transports into the cytoplasm, to protect DHX9 from being ubiquitinated and degraded. From the KEGG analysis of Next-Generation Sequencing, the NF-κB pathway was one of the most regulated pathways by SNORA42. SNORA42 enhanced phosphorylation of p65 and this effect could be reversed by NF-κB inhibitor, BAY11–7082. Moreover, SNORA42 activated NF-κB signaling through promoting the transcriptional co-activator DHX9 interacted with p-p65, inducing NF-κB downstream gene expression. In summary, our study highlights the potential of SNORA42 is up-regulated in ESCC and promotes ESCC development partly via interacting with DHX9 and triggering the DHX9/p65 axis.

Trichostatin A promotes esophageal squamous cell carcinoma cell migration and EMT through BRD4/ERK1/2-dependent pathway.

BackgroundHistone deacetylases (HDACs) have been demonstrated to be aberrantly activated in tumorigenesis and cancer development. Thus, HDAC inhibitors (HDACIs) are considered to be promising anti‐cancer therapeutics. However, recent studies have shown that HDACIs promote the migration of many cancer cells. Therefore, there is a need to elucidate the underlying mechanisms of HDACIs on cancer cell migration to establish a combination therapy that overcomes HDACI‐induced cell migration.MethodsKYSE‐150 and EC9706 cells were treated differently. Effects of drugs and siRNA treatment on tumor cell migration and cell signaling pathways were investigated by transwell migration assy. Gene expression for SNAI2 was tested by RT‐qPCR. Western blot analysis was employed to detect the level of E‐cadherin, β‐catenin, vimentin,Slug，ERK1/2, H3, PAI‐1 and BRD4. The effect of drugs on cell morphology was evaluated through phase‐contrast microscopic images.ResultsTSA promotes epithelial‐mesenchymal transition (EMT) in ESCC cells by downregulating the epithelial marker E‐cadherin and upregulating mesenchymal markers β‐catenin, vimentin, Slug, and PAI‐1. Knockdown of Slug by siRNA or inhibition of PAI‐1 clearly suppressed TSA‐induced ESCC cell migration and resulted in the reversal of TSA‐triggered E‐cadherin, β‐catenin, and vimentin expression. However, no crosstalk between Slug and PAI‐1 was observed in TSA‐treated ESCC cells. Blocking ERK1/2 activation also inhibited TSA‐induced ESCC cell migration, EMT, and upregulation of Slug and PAI‐1 levels in ESCC cells. Interestingly, inhibition of BRD4 suppressed TSA‐induced ESCC cell migration and attenuated TSA‐induced ERK1/2 activation and upregulation of Slug and PAI‐1 levels.ConclusionsOur data indicate the existence of at least two separable ERK1/2‐dependent signaling pathways in TSA‐mediated ESCC cell migration: an ERK1/2–Slug branch and an ERK1/2‐PAI‐1 branch. Both branches of TSA‐induced ESCC cell migration appear to favor the EMT process, while BRD4 is responsible for two separable ERK1/2‐dependent signaling pathways in TSA‐mediated ESCC cell migration.

METTL3 promotes tumour development by decreasing APC expression mediated by APC mRNA N6-methyladenosine-dependent YTHDF binding

The adenomatous polyposis coli (APC) is a frequently mutated tumour suppressor gene in cancers. However, whether APC is regulated at the epitranscriptomic level remains elusive. In this study, we analysed TCGA data and separated 200 paired oesophageal squamous cell carcinoma (ESCC) specimens and their adjacent normal tissues and demonstrated that methyltransferase-like 3 (METTL3) is highly expressed in tumour tissues. m6A-RNA immunoprecipitation sequencing revealed that METTL3 upregulates the m6A modification of APC, which recruits YTHDF for APC mRNA degradation. Reduced APC expression increases the expression of β-catenin and β-catenin-mediated cyclin D1, c-Myc, and PKM2 expression, thereby leading to enhanced aerobic glycolysis, ESCC cell proliferation, and tumour formation in mice. In addition, downregulated APC expression correlates with upregulated METTL3 expression in human ESCC specimens and poor prognosis in ESCC patients. Our findings reveal a mechanism by which the Wnt/β-catenin pathway is upregulated in ESCC via METTL3/YTHDF-coupled epitranscriptomal downregulation of APC.

RAD001 targeted HUVECs reverses 12-lipoxygenase-induced angiogenesis in oesophageal squamous cell carcinoma.

12‐LOX plays an important role in the progression of various malignancies. However, the underlying mechanisms of the action of 12‐LOX and tumour treatment strategies remain not fully defined. In this study, we investigated the possible roles of 12‐LOX in ESCC and explored the new therapeutic target. Approximately 73% of ESCC tissues showed marked up‐regulation of 12‐LOX, which was associated with poor prognosis. 12‐LOX overexpression was positively correlated with the malignant progression of ESCC as demonstrated both in vitro and in vivo. Up‐regulation of 12‐LOX significantly increased the proliferation of ESCC cells and the xenograft volume. Moreover, 12‐LOX up‐regulation promoted tube formation of HUVECs and tumour angiogenesis in xenografts. Mechanism investigation indicated that 12‐LOX overexpression led to activation of the PI3K/AKT/mTOR pathway and the up‐regulation of VEGF in ESCC cells. Subsequent analysis indicated that the RAD001 could reverse the 12‐LOX‐induced promoting effect on ESCC. Specifically, the application of RAD001 inhibited the proliferation of ESCC cells and the tube‐forming ability of HUVECs. In the drug group, the xenografts exhibited significant volume reduction and angiogenesis inhibition. We demonstrated that RAD001 could inhibit HUVEC migration. These findings presented the evidence that RAD001 had distinct roles on HUVECs and could exert anti‐tumour effects by targeting not only the PI3K/AKT/mTOR pathway but the angiogenesis in ESCC.

HPV16 infection promotes an M2 macrophage phenotype to promote the invasion and metastasis of esophageal squamous cell carcinoma.

High-risk human papillomavirus (HR-HPV) is an important risk factor for esophageal cancer. Macrophages constitute a crucial immune medium for regulating HPV-related tumors; however, the specific regulatory mechanisms remain unknown. Therefore, the purpose of our current study was to investigate the mechanism by which HPV16E6 regulates macrophages to promote the invasion and metastasis of esophageal cancer. HPV16E6 infection was detected by polymerase chain reaction. Immunohistochemistry was used to verify the distribution of tumor-associated macrophages (TAMs) and MMP-9 expression in esophageal squamous cell carcinoma tissues (ESCCs), and cancer adjacent normal tissues (CANs) from Kazakh patients. ESCC cells were transfected with a plasmid over-expressing HPV16E6 and non-contact cocultured with macrophages. The infection rate of HPV16E6 in Kazakh ESCCs was clearly higher than that in CANs (P < 0.05). The density of CD163-positive TAMs was significantly positively correlated with HPV16E6 infection in ESCCs (P < 0.05). After coculturing macrophages and EC9706 cells transfected with the HPV16E6 plasmid, the phenotype of macrophages transformed into M2 macrophages. The migration and invasion ability of ESCC cells were higher in the HPV16E6-transfected and coculture group than in the HPV16E6 empty vector-transfected and non-cocultured HPV16E6-transfected groups (all P < 0.05). The density of M2-like TAMs in ESCCs was positively correlated with the level of MMP-9 expression. MMP-9 expression in the HPV16E6-ESCC coculture macrophages group was substantially higher than that in controls (all P < 0.05). HPV16 infection mediates tumor-associated macrophages to promote ESCC invasion and migration.

Human Adipose-Derived Stem/Stromal Cells Promote Proliferation and Migration in Head and Neck Cancer Cells.

Human adipose-derived stem/stromal cells (ASCs) are increasingly used as auto-transplants in regenerative medicine to restore tissue defects or induce wound healing, especially in cancer patients. The impact of ASCs on squamous cell carcinoma of the upper aerodigestive tract (UAT) including head and neck and esophageal squamous cell carcinoma (HNSCC and ESCC) is not yet fully understood. ASCs were cultured from subcutaneous, abdominal lipoaspirates of five patients, who received auto-transplants to the head and neck. Supernatants were tested for paracrine effects in functional in vitro assays of proliferation of HNSCC tumor cell line FaDu and ESCC cell line Kyse30, and their cell migration/invasion capacities in Boyden chambers, in addition to endothelial tube formation assay using human umbilical vein endothelial cells (HUVECs). All ASC-derived supernatants enhanced proliferation of FaDu cells, invasive migration, and tube formation by HUVECs, compared to controls. Of five patients' lipoaspirates, ASC-derived supernatants of four patients increased proliferation and invasive migration in Kyse30 cells. The data suggests that ASCs can promote tumor cell proliferation, invasiveness, and neo-angiogenesis in these tumor cell lines of the UAT and HUVEC in a paracrine manner. Although clinical studies on the subject of oncological safety are still needed, these findings emphasize the importance of complete tumor removal before ASCs are used in the head and neck.

TMEM161B-AS1 suppresses proliferation, invasion and glycolysis by targeting miR-23a-3p/HIF1AN signal axis in oesophageal squamous cell carcinoma.

Mounting data have shown that long non‐coding RNAs (lncRNAs) widely participate in tumour initiation, development, progression and glycolysis in a variety of tumours. However, the clinical prognosis and molecular mechanisms of TMEM161B‐AS1 in oesophageal squamous cell carcinoma (ESCC) remain still unknown. Here, TMEM161B‐AS1 and HIF1AN were significantly lower in ESCC tissues than in normal samples, and their low expressions were both related to TNM stage, lymph node metastasis and poor prognosis of ESCC patients. Functionally, TMEM161B‐AS1 overexpression or miR‐23a‐3p depletion suppressed the proliferation, invasion and glycolysis as well as reduced glucose consumption and lactate production in ESCC cells. Mechanistically, TMEM161B‐AS1 manipulated HIF1AN expression by competitively sponging miR‐23a‐3p in ESCC cells. MiR‐23a‐3p mimic and HIF1AN siRNA partly reversed cell phenotypes mediated by TMEM161B‐AS1 in ESCC cells. Collectively, TMEM161B‐AS1, miR‐23a‐3p and HIF1AN may be tightly involved in ESCC development and progression as well as patients’ prognosis, and TMEM161B‐AS1/miR‐23a‐3p/HIF1AN signal axis may be a promising target for the treatment of ESCC patients.

NOTCH3 limits the epithelial-mesenchymal transition and predicts a favorable clinical outcome in esophageal cancer.

BackgroundEsophageal squamous cell carcinoma (ESCC) is the deadliest of all human squamous cell carcinomas and is characterized by chemotherapy resistance and poor prognosis associated with the epithelial–mesenchymal transition (EMT). A subset of ESCC displays loss‐of‐function mutations in genes encoding Notch receptor family members, including NOTCH3. Although Notch signaling regulates EMT in ESCC cells, the role of NOTCH3 in EMT and chemotherapy resistance remains elusive. This study aimed to examine the role of NOTCH3 in EMT and chemotherapy resistance, and determine whether NOTCH3 expression can be used to predict the response to chemotherapy.MethodsIn vitro and in vivo assays were conducted to clarify the contribution of NOTCH3 to chemotherapy resistance. Using specimens from 120 ESCC patients treated with neoadjuvant chemotherapy, we compared the expression levels of NOTCH3 and genes involved in EMT according to the degree of chemotherapy sensitivity.ResultsIn ESCC cells, chemotherapy resistance was associated with NOTCH3 downregulation and concurrent activation of EMT. RNA interference to silence NOTCH3 resulted in induction of the EMT marker Vimentin (VIM), leading to chemotherapy resistance in ESCC cells. Conversely, ectopic expression of the activated form of NOTCH3 suppressed EMT and sensitized cells to chemotherapy. Results of chromatin immunoprecipitation assays suggested that NOTCH3 may repress transcription of the VIM.ConclusionsOur findings suggest that NOTCH3 may control chemotherapy sensitivity by regulating EMT. NOTCH3 may serve as a novel biomarker to predict better clinical outcomes in ESCC patients.

LINC00958 promotes proliferation, migration, invasion, and epithelial-mesenchymal transition of oesophageal squamous cell carcinoma cells.

Oesophageal cancer is one of the deadliest cancers in the world. Oesophageal squamous cell carcinoma (ESCC) is the most prevalent histological type of oesophageal cancer. Oesophageal cancer has a poor prognosis because of its invasiveness. Thus, it is especially important to seek effective treatment methods. Research indicates that long non-coding RNAs (lncRNAs) play a significant role in the occurrence and development of oesophageal cancer. The aim of this study was to describe the role of LINC00958 in ESCC. Bioinformatics and real-time quantitative polymerase chain reaction (RT-qPCR) methods were utilized to predict and verify the expression of LINC00958 in ESCC. Related functional experiments, including cell proliferation, migration and invasion, were performed. In addition, a western blot and a dual luciferase reporter gene experiment were used to study the detailed carcinogenic mechanism of LINC00958. The results indicated there was a high expression of LINC00958 in ESCC, which promoted proliferation, migration, invasion and Epithelial-Mesenchymal Transition (EMT) of ESCC cells, and this effect may be via regulating miR-510-5p.

Porphyromonas gingivalis infection exacerbates oesophageal cancer and promotes resistance to neoadjuvant chemotherapy.

The effect of Porphyromonas gingivalis (Pg) infection on oesophageal squamous cell carcinoma (ESCC) prognosis, chemotherapeutic efficacy, and oesophageal cancer cell apoptosis resistance and proliferation remain poorly understood. Clinicopathological data from 312 ESCC oesophagectomy patients, along with the computed tomography imaging results and longitudinal cancerous tissue samples from a patient subset (n = 85) who received neoadjuvant chemotherapy (NACT), were analysed. Comparison of overall survival and response rate to NACT between Pg-infected and Pg-uninfected patients was made by multivariate Cox analysis and Response Evaluation Criteria in Solid Tumours v.1.1 criteria. The influence of Pg on cell proliferation and drug-induced apoptosis was examined in ESCC patients and validated in vitro and in vivo. The 5-year overall survival was lower in Pg-positive patients, and infection was associated with multiple clinicopathological factors and pathologic tumour, node, metastasis stage. Of the 85 patients who received NACT, Pg infection was associated with a lower response rate and 5-year overall survival. Infection with Pg resulted in apoptosis resistance in ESCC and promoted ESCC cell viability, which was confirmed in longitudinal cancerous tissue samples. Pg-induced apoptosis resistance was dependent on fimbriae and STAT3. Pg infection is associated with a worse ESCC prognosis, reduced chemotherapy efficacy, and can potentiate the aggressive behaviour of ESCC cells.

High-resolution spatiotemporal pHe and pO2 imaging in head and neck and oesophageal carcinoma cells

BackgroundpO2 and pH are physiological parameters relevant for different processes in health and disease, including wound healing and cancer progression. Head and neck squamous cell carcinomas (HNSCC) and oesophageal squamous cell carcinomas (ESCC) have a high rate of local recurrence that is partly related to treatment-resistant residual tumour cells. Hence, novel diagnostic tools are required to visualise potential residual tumour cells and thereby improve treatment outcome for HNSCC and ESCC patients. We developed a device to spatiotemporally measure oxygen consumption rates (OCR) and extracellular acidification rates (ECAR) to distinguish HNSCC and ESCC cells from healthy cells in vitro, exploiting general metabolic differences between cancer cells and healthy cells.MethodsOCR and ECAR were measured via a newly developed device named STO2p-Q (SpatioTemporal O2 and pH Quantification) using the VisiSens technology based on ratiometric fluorescence imaging, facilitating spatiotemporal resolution. Results were confirmed using extracellular flux analyses (Seahorse technology).ResultsSTO2p-Q is described and used to measure OCR and ECAR in HNSCC and ESCC cell lines and normal fibroblast and epithelial cells as components of the tumour microenvironment. OCR measurements showed differences amongst HNSCC and ESCC cell lines and between HNSCC/ESCC and normal cells, which on average had lower OCR than HNSCC/ESCC cells. Both OCR and ECAR measurements were independently verified using the Seahorse technology. Additionally, using STO2p-Q, HNSCC/ESCC, and normal cells could be spatially resolved with a resolution in the low millimetre range.ConclusionsWe developed a method to spatiotemporally measure OCR and ECAR of cells, which has many potential in vitro applications and lays the foundation for the development of novel diagnostic tools for the detection of cancerous tissue in HNSCC and ESCC patients in vivo.

High-mobility group AT-hook 2 promotes growth and metastasis and is regulated by miR-204-5p in oesophageal squamous cell carcinoma.

To investigate the expression of high-mobility group AT-hook 2 (HMGA2) and miR-204-5p in oesophageal squamous cell carcinoma (ESCC) and their biological roles in ESCC development and progression. HMGA2 and miR-204-5p expression levels in ESCC tissues and cell lines were detected by qRT-PCR, Western blotting and immunohistochemical staining. ESCC cell lines were transfected with a small interfering RNA for HMGA2 and miR-204-5p mimic to downregulate and upregulate the expression levels of HMGA2 and miR-204-5p, respectively. The growth, migration and invasion abilities of ESCC cells were assessed by MTT, colony formation, wound-healing and Transwell assays, respectively. A luciferase reporter gene assay was used to determine whether the 3'-untranslated coding regions of HMGA2 could be directly bound by miR-204-5p. HMGA2 expression was markedly upregulated (P<.001), while miR-204-5p expression was markedly downregulated (P=.003) in ESCC tissues compared with adjacent normal tissues. HMGA2 expression was correlated with tumour size, invasion depth, lymph node metastasis and tumour-node-metastasis stage (all P<.05) and was identified as an independent prognostic factor for ESCC patients. The expression levels of HMGA2 and miR-204-5p were negatively correlated (r2 =0.609, P<.001). HMGA2 knockdown or miR-204-5p overexpression markedly inhibited ESCC cell growth, migration and invasion (P<.05). In addition, restoration of HMGA2 expression partly reversed the inhibitory effects of miR-204-5p overexpression on migration and invasion (P<.05). The luciferase reporter gene assay suggested that HMGA2 is a direct downstream target of miR-204-5p. HMGA2 functions as an oncogene in the growth and metastasis of ESCC and is negatively regulated by miR-204-5p.

PER2 Circadian Oscillation Sensitizes Esophageal Cancer Cells to Chemotherapy.

Simple SummaryThere are growing evidences that the circadian rhythm modulates key cellular processes in physiological and pathological conditions. Here, we characterized the consequences of the daily oscillations of the clock-related gene PER2 in esophageal cancer cells and found that chemotherapy is more efficient when PER2 expression is low. These results suggest that chronotherapy might be used to potentiate the impact of current chemotherapy regimen.Esophageal squamous cell carcinoma (eSCC) accounts for more than 85% cases of esophageal cancer worldwide and the 5-year survival rate associated with metastatic eSCC is poor. This low survival rate is the consequence of a complex mechanism of resistance to therapy and tumor relapse. To effectively reduce the mortality rate of this disease, we need to better understand the molecular mechanisms underlying the development of resistance to therapy and translate that knowledge into novel approaches for cancer treatment. The circadian clock orchestrates several physiological processes through the establishment and synchronization of circadian rhythms. Since cancer cells need to fuel rapid proliferation and increased metabolic demands, the escape from circadian rhythm is relevant in tumorigenesis. Although clock related genes may be globally repressed in human eSCC samples, PER2 expression still oscillates in some human eSCC cell lines. However, the consequences of this circadian rhythm are still unclear. In the present study, we confirm that PER2 oscillations still occur in human cancer cells in vitro in spite of a deregulated circadian clock gene expression. Profiling of eSCC cells by RNAseq reveals that when PER2 expression is low, several transcripts related to apoptosis are upregulated. Consistently, treating eSCC cells with cisplatin when PER2 expression is low enhances DNA damage and leads to a higher apoptosis rate. Interestingly, this process is conserved in a mouse model of chemically-induced eSCC ex vivo. These results therefore suggest that response to therapy might be enhanced in esophageal cancers using chronotherapy.

Expression of LncRNA DLEU1 in Esophageal Squamous Cell Carcinoma and Its Effect on Proliferation and Migration of ESCC Cells

Expression of LncRNA DLEU1 in Esophageal Squamous Cell Carcinoma and Its Effect on Proliferation and Migration of ESCC Cells

Downregulation of long non-coding RNA LOC101928477 correlates with tumor progression by regulating the epithelial-mesenchymal transition in esophageal squamous cell carcinoma.

BackgroundEsophageal squamous cell carcinoma (ESCC) is one of the deadliest malignancies. There is a growing body of evidence showing that long non‐coding RNAs (lncRNAs) play critical roles in ESCC oncogenesis. The present study aimed to explore the role of LOC101928477, a newly discovered lncRNA, in the development and metastasis of ESCC.MethodsIn this study, real‐time PCR, western blotting, cell counting kit‐8 (CCK‐8), flow cytometry, colony formation, wound healing, transwell migration/invasion assay, immunofluorescence, and immunohistochemistry were used. We also applied an in situ xenograft mouse model and a lung metastasis mouse model to verify our findings.ResultsWe determined that LOC101928477 expression was inhibited in ESCC tissue and ESCC cell lines when compared with controls. Moreover, forced expression of LOC101928477 effectively inhibited ESCC cell proliferation, colony formation, migration, and invasion via suppression of epithelial‐mesenchymal transition (EMT). Furthermore, LOC101928477 overexpression inhibited in situ tumor growth and lung metastasis in a mouse model.ConclusionsTogether, our results suggested that LOC101928477 could be a novel suppressor gene involved in ESCC progression.

CTCF-silenced miR-137 contributes to EMT and radioresistance in esophageal squamous cell carcinoma

BackgroundEsophageal squamous cell carcinoma (ESCC) is one of the most malignant tumors in gastrointestinal system. MicroRNAs (miRNAs) have been reported to be implicated in cancer development. However, the role of miR-137 has not been fully revealed in ESCC.MethodsQuantitative real-time polymerase chain reaction (qRT-PCR) and western blot analyses were separately used to examine RNA level and protein level. 5-ethynyl-2′-deoxyuridine (EdU) assay, transwell assays and flow cytometry analyses were conducted to assess biological behaviors of ESCC cells. Additionally, the interaction between genes were analyzed via Chromatin Immunoprecipitation (ChIP) assay, RNA Binding Protein Immunoprecipitation (RIP) assay, RNA pull down assay and luciferase reporter assay.ResultsMiR-137 was down-regulated in ESCC cells. Upregulation of miR-137 hindered ESCC cell proliferation, migration, invasion and epithelial mesenchymal transition (EMT). Besides, miR-137 enhanced the sensitivity of ESCC cells to irradiation. Moreover, CCCTC-binding factor (CTCF) inactivated miR-137 transcription in ESCC cells. Furthermore, we revealed enhancer of zeste 2 polycomb repressive complex 2 subunit (EZH2) and paxillin (PXN) as the downstream targets of miR-137. In turn, EZH2 was recruited by CTCF and induced methylation in miR-137 promoter.ConclusionCTCF/Suz12/EZH2 complex-silenced miR-137 facilitates ESCC progression and radioresistance by targeting EZH2 and PXN.

Inhibition of SOCS6 confers radioresistance in esophageal squamous cell carcinoma

Esophageal cancer is one of the most common cancer of the digestive system and radiotherapy is widely applied in advanced esophageal cancer treatment, however radioresistance (RR) is one of the major reasons for radiotherapy failure. There is limited knowledge on the mechanisms that cause RR, here we identify suppressors of cytokine signaling 6 (SOCS6) is a negative regulator of radioresistance in ESCC cells. SOCS6 deficiency in ESCC cells conferred radioresistance in vitro and in vivo by increasing radiation-induced G2/M arrest, DNA damage repair and inhibiting radiation-induced apoptosis. Moreover, the transcriptome sequencing analysis demonstrates that the transcription of SOCS6 was partially p53-dependent. Importantly we found that highly correlated SOCS6 and P53 express lower in RR esophageal cancer tissues compare with radiosensitive ones. Collectedly our study uncovers that SOCS6, as a downstream effector of p53, is a key regulator involved in the radioresistance of ESCC.