Esophageal Squamous Cell Cancer Cell Lines Research Articles

Role of heat shock protein 90 in hypoxia-induced angiogenesis and epithelial-mesenchymal transition for esophageal squamous cancer cells.

395 Background: Hypoxia is known as an important trigger for the development and progression of human cancers. Heat shock proteins (Hsps) may be up-regulated in response to cellular stressors including hypoxia. To date, the functional role of Hsps within hypoxic tumor microenvironment for esophageal squamous cell cancer (ESCC) remains poorly defined. Methods: CoCl2 was used to induce hypoxia that mimics a hypoxic tumor microenvironment in cultured ESCC cells. Successful induction of hypoxia was confirmed by 2’,7’ –dichlorofluorescein diacetate (DCFDA) assay by detection of cellular reactive oxygen species (ROS). 7-Dimethylaminoethylamino-17-demethoxygeldanamycin (17-DMAG), a selective Hsp90 inhibitor, was used to treat 2 ESCC cell lines, KYSE-170 and -510 cells pretreated with or without CoCl2, an agent to induce a hypoxic tumor microenvironment. Cytotoxicity (MTT) and migration assays were conducted in KYSE-17 and -510 ESCC cells in response to different concentrations of CoCl2, followed by protein expression of Hsp 90, vascular endothelial growth factor (VEGF), hypoxia-inducible factor-1a (HIF-1a), mTOR as well as markers related epithelial-mesenchymal transition (EMT) such as snail or E-cadherin, by immunoblot or ELISA. In parallel, cell proliferation and migration assays of ESCC cells were analyzed. Results: CoCl2 induced hypoxia was supported by an induction of reactive oxygen species (ROS). CoCl2 (200 mM) significantly suppressed cell viability and proliferation with a concomitant up-regulation of VEGF and HIF-1a in a dose-dependent fashion. In contrast, cell migration was significantly increased in response to CoCl2, while down-regulating E-cadherin with concomitant increase in Snail expression. 17-DMAG decreased expression of VEGF and HIF-1a. In addition, it inhibited cell migration and invasion of ESCC cells were analyzed. Conclusions: Our data have shown that CoCl2 induced hypoxia promotes EMT and angiogenesis, which are inhibited by 17-DMAG, suggesting that hypoxia induced EMT and angiogenesis is Hsp 90 dependent in ESCC.

Co-occurrence of mutations and related signal pathway analysis of CCND1 amplification in esophageal squamous cell cancer.

e16044 Background: Profiling molecular subtypes was usually necessary for cancer patients to facilitate better treatment strategy. Esophageal squamous cell cancer (ESCC) has four subtypes including cell cycle pathway activation (CCA), NRF2 oncogenic activation (NRFA), immune suppression (IS), and immune modulation (IM). CCND1 amplification is one of the important molecular biomarkers for CCA subtype. Previous research showed that CCND1 amplification was associated with immune resistance in ESCC. The co-occurred mutations and related signaling pathways are of great interest to study molecular mechanism in ESCC. Methods: This study enrolled 50 ESCC patient samples comprising 19 whole exome sequencing (WES) samples, 18 whole genome sequencing (WGS) samples and 13 NGS panel (667 genes) samples. To use all the samples, the minimal set of 667 genes was analyzed in detail for gene amplifications and mutations. Kaplan-Meier (KM) survival analysis was applied to study the prognosis associations with the frequently occurred amplifications including CCND1, FGF3, FGF4 and FGF19, etc. Gene expression profiles were then investigated by RNA-Seq sequencing on ESCC cell lines with CCND1 (K30-N) and without CCND1 gene (K30-S, knocked out). PCA analysis was applied to explore the differences between K30-S and K30-N, and KEGG and GO enrichment analysis were performed on the differential expressed genes (DEGs). All analyses were carried out through R4.1.0. Results: The mutational profiles showed that TP53, CCND1, FGF4, FGF19, FGF3, and CDKN2A/B were the most frequently mutated genes in ESCC patients, with the mutation frequencies of 62%, 58%, 56%, 50%, 48% and 40%, respectively. Among those genes, CCND1 and FGF3/4/19 co-occurred amplifications presented in almost all the samples and no other co-existent gene amplifications were identified. The CCND1 and FGF3/4/19 amplification patients were associated with worse prognosis. A total of 1494 differential expressed genes were identified between K30-N and K30-S cell lines, including 998 up-regulated genes and 496 down-regulated gene in K30-S cell line. KEGG enrichment analysis showed that these DEGs were mainly enriched in MAPK signaling pathway, p53 signaling pathway, mTOR signaling pathway and etc. GO enrichment analysis revealed that these differential genes are mainly enriched in cell growth, developmental cell growth, Ras protein signal transmission. Those results were consistent with CCA molecular subtype and highlighted the important role of CCND1 in ESCC subtype classification. Conclusions: This study demonstrated that CCND1 and FGF3/4/19 amplifications frequently co-occurred in ESCC and they were associated with worse prognosis. Signal pathway analysis showed CCND1 play important roles in subtype classification of ESCC.

Computational Drug Repurposing Approach to Identify Novel Inhibitors of ILK Protein for Treatment of Esophageal Squamous Cell Carcinoma.

Esophageal squamous cell cancer (ESCC) is a deadly malignant tumor characterized by an overall 5-year survival rate below 20%, with China accounting for approximately 50% of all cases worldwide. Our previous studies have demonstrated that high integrin-linked kinase (ILK) expression plays a key role in development and progression of ESCC both in vitro and in vivo. Here, we employed the drug repurposing approach to identify a novel FDA-approved anticancer inhibitor against ILK-induced tumorigenesis and progression. We screened the ZINC15 database and predicted the molecular docking ability among FDA-approved and publicly available drugs to ILK and then performed computational docking and visual inspection analyses of the top 10 ranked drugs. Two computer-based virtual screened drugs were evaluated in vitro for their ability to directly bind purified ILK by surface plasmon resonance. Cytotoxicity of the two candidate drugs was validated in vitro using CCK-8 and LDH assays. We initially selected the top 10 compounds, based on their minimum binding energy to the ILK crystal, after molecular docking and subjected them to further screening. Taking the binding energy of -10 kcal/mol as the threshold, we selected two drugs, namely, nilotinib and teniposide, for the wet-lab experiment. Surface plasmon resonance (SPR) revealed that nilotinib and teniposide had equilibrium dissociation constant (KD) values of 6.410E - 6 and 1.793E - 6, respectively, which were lower than 2.643E - 6 observed in ILK-IN-3 used as the positive control. The IC50 values for nilotinib and teniposide in ESCC cell lines were 40 μM and 200-400 nM, respectively. Results of the CCK-8 assay demonstrated that both nilotinib and teniposide significantly inhibited proliferation of cells (P < 0.01). LDH results revealed that both drugs significantly suppressed the rate of cell death (P < 0.01). The drug repositioning procedure can effectively identify new therapeutic tools for ESCC. Our findings suggest that nilotinib and teniposide are efficacious inhibitors of ILK and thus have potential to target ILK-mediated signaling pathways for management of ESCC.

CD155 Cooperates with PD-1/PD-L1 to Promote Proliferation of Esophageal Squamous Cancer Cells via PI3K/Akt and MAPK Signaling Pathways.

Esophageal cancer is still a leading cause of death among all tumors in males, with unsatisfactory responses to novel immunotherapies such as anti-PD-1 agents. Herein, we explored the role of CD155 in esophageal squamous cell cancer (ESCA) and its underlying molecular mechanisms. Publicly available datasets were used for differential gene expression and immune infiltration analyses, and their correlation with patient survival. A total of 322 ESCA and 161 paracancer samples were collected and evaluated by performing immunohistochemistry and the H score was obtained by performing semiquantitative analysis. In vitro transfection of ESCA cell lines with lentivirus vectors targeting CD155 was performed to knockdown the protein. These cells were analyzed by conducting RNA sequencing, and the effects of CD155 knockdown on cell cycle and apoptosis were verified with flow cytometry and Western blotting. In addition, in vivo experiments using these engineered cell lines were performed to determine the role of CD155 in tumor formation. A small interfering RNA-mediated knockdown of Nectin3 was used to determine whether it phenocopied the profile of CD155 knockdown. CD155 is highly expressed in ESCA tissues and is positively associated with PD1, PDL1, CD4, IL2RA, and S100A9 expression. Furthermore, CD155 knockdown inhibited ESCA cells' proliferation by impairing the cell cycle and inducing cell apoptosis. Bioinformatics analysis of the gene expression profile of these engineered cells showed that CD155 mainly contributed to the regulation of PI3K/Akt and MAPK signals. The downregulation of Nectin3 expression phenocopied the profile of CD155 knockdown. CD155 may cooperate with PD-1/PD-L1 to support ESCA proliferation in ways other than regulating its underlying immune mechanisms. Indeed, CD155 downregulation can impair ESCA cell pro-cancerous behavior via the inhibition of the PI3K/Akt and MAPK signaling pathways. Moreover, Nectin3 may be a ligand of CD155 and participate in the regulation of ESCA cells' proliferation. Hence, the inhibition of CD155 may enhance the therapeutic effect of anti-PD-1 immunotherapies in ESCA.

LncRNA BBOX1-AS1 silencing inhibits esophageal squamous cell cancer progression by promoting ferroptosis via miR-513a-3p/SLC7A11 axis

Long noncoding RNA BBOX1 antisense 1 (BBOX1-AS1) has been demonstrated to play important roles in several tumors. However, the expression and function of BBOX1-AS1 in esophageal squamous cell cancer (ESCC) have not been defined. Here, BBOX1-AS1 expression in 78 collected ESCC tissues, paired adjacent normal tissues, and ESCC cell lines were analyzed using quantitative real-time polymerase chain reaction. The overall survival of the patients was also studied. Cell proliferation, invasion, and migration were verified by constructing in vitro models. Additionally, cell apoptosis was determined by flow cytometry, and ferroptosis was examined using Ptgs2 detection and lipid-reactive oxygen species assays. The relationship between BBOX1-AS1 and downstream molecules was evaluated using RNA immunoprecipitation, western blotting, and luciferase reporter assays. The function of BBOX1-AS1 was studied in vivo using a xenograft model and immunohistochemistry. BBOX1-AS1 expression was significantly higher in ESCC tissues, indicating poor prognosis. Inhibition of BBOX1-AS1 reduced cell proliferation, slowed cell invasion and migration, and promoted apoptosis and ferroptosis in vitro. miR-513a-3p was verified as a specific target of BBOX1-AS1 in ESCC, whereas knockdown of miR-513a-3p reversed the suppressive function of BBOX1-AS1 silencing in TE-1 cells. Moreover, solute carrier family 7 member 11 (SLC7A11) is regulated by miR-513a-3p, which is mediated by BBOX1-AS1 in ESCC cells. In conclusion, downregulation of BBOX1-AS1 inhibits cell proliferation, and metastasis accelerates cell apoptosis and ferroptosis in ESCC by upregulating miR-513a-3p to reduce SLC7A11 expression. These findings may provide novel insights into the diagnosis and treatment of ESCC.

Protocadherin B9 Is Associated with Human Esophageal Squamous Cell Carcinoma Progression

Introduction: Esophageal cancer is the sixth leading cause of cancer-related death worldwide. However, molecular targeted therapy and novel therapeutic targets are needed for esophageal squamous cell cancer (ESCC). In a previous study, we reported that protocadherin (PCDH) B9 plays an important role in several cancers. Therefore, in this study, we examined the clinical significance of PCDHB9 expression in ESCC. Methods: PCDHB9 expression was examined using immunohistochemistry in 128 cases and using quantitative reverse transcription-polymerase chain reaction in 16 cases of ESCC. PCDHB9 function in ESCC cells was examined using RNA interference. Results: High PCDHB9 expression was identified in 5 of 16 (31.3%). In total, 51 (40%) ESCC cases showed strong PCDHB9 expression, whereas nonneoplastic mucosa rarely showed its expression. High PCDHB9 expression was significantly associated with T classification, N grade, and stage in ESCC. In ESCC cell lines, PCDHB9 knockdown affected cell growth, migration, and adhesion. Further, the expression of integrin (ITG) A3, ITGA4, ITGA5, ITGB1, ITGB6, vimentin, snail family transcriptional repressor 1, and cadherin 2 (NCAD) was significantly reduced and cadherin 1 was significantly increased in PCDHB9 knockdown ESCC cells. Conclusion: These results suggest that PCDHB9 plays a tumor-promoting role and is a potential biomarker and therapeutic target in ESCC.

CircGOT1 promotes cell proliferation, mobility, and glycolysis-mediated cisplatin resistance via inhibiting its host gene GOT1 in esophageal squamous cell cancer

ABSTRACT Esophageal squamous cell cancer (ESCC) is a prevalent malignant cancer with high incidence and fatality rate. Surging evidences have revealed that circular RNAs (circRNAs) act key role in ESCC tumorigenesis and progression. Therefore, the purpose of this study is to explore the role and regulatory mechanism of a novel circGOT1 in ESCC. In the present study, the transcriptional expression of circGOT1, miR-606 and GOT1, and the epithelial–mesenchymal transition (EMT) and apoptosis-related markers were examined by quantitative PCR. The protein levels of GOT1 and glycolysis-related proteins were detected by Western blotting. In addition, the glycolytic levels were determined via measuring glucose uptake, lactate production, and ATP levels. Then, the function experiments and rescue experiments were used to investigate the function and mechanism of circGOT1 in ESCC. In addition, RNA immunoprecipitation, pull-down, and luciferase activity reporter gene assays were used to analyze the circGOT1/miR-606/GOT1 axis. The xenograft mouse mode was used to determine the function of circGOT1 in vivo. Here, we identified that circGOT1 and GOT1 upregulate, whereas miR-606 was reduced in ESCC tissues and cell lines. High circGOT1 and GOT1 expression associated with poor survival and worse prognosis of ESCC patients, but miR-606 revealed opposite traits. Mechanically, circGOT1 sponged miR-606 to promote GOT1, which induced cell proliferation, migration, aerobic glycolysis, and cisplatin resistance. The tumor growth was reduced by circGOT1 inhibition in xenograft mouse. Our results indicate the oncogene role of circGOT1 in ESCC via an endogenous competition RNA (ceRNA) mechanism to promote GOT1 expression via sponging miR-606.

547 THE ROLE OF HEAT SHOCK PROTEIN 90 IN HYPOXIA INDUCED ANGIOGENESIS AND EPITHELIAL-MESENCHYMAL TRANSITION OF ESOPHAGEAL SQUAMOUS CELL CANCER

Abstract Hypoxia is known as an important trigger for the development of metastases in human cancers. Heat shock proteins (Hsps) are up-regulated by cellular stressors including hypoxia. To date, the functional role of Hsps within the hypoxic tumor microenvironment for esophageal squamous cell cancer (ESCC) remains poorly defined. Methods CoCl₂ was used to induce hypoxia in cultured ESCC cells which was confirmed by 2′,7′ –dichlorofluorescin diacetate (DCFDA) assay. 7-Dimethylaminoethylamino-17-demethoxygeldanamycin (17-DMAG), a selective Hsp90 inhibitor, was used to treat 2 ESCC cell lines, KYSE-170 and -510 cells pretreated with or without CoCl₂₂₂₂₂ in different concentrations, followed by cytotoxicity (MTT) and migration assays. In parallel, expression of Hsp90, vascular endothelial growth factor (VEGF), hypoxia-inducible factor-1α (HIF-1α), and markers related to epithelial-mesenchymal transition (EMT) such as snail/E-cadherin, by immunoblot or ELISA while analyzing cell proliferation and migration of treated ESCC cells. Results CoCl₂ induced hypoxia was supported by induction of reactive oxygen species (ROS). CoCl₂ (200 μM) significantly suppressed cell viability and proliferation with a concomitant up-regulation of VEGF and HIF-1α in a dose-dependent fashion. In contrast, cell migration was significantly increased in response to CoCl₂ while down-regulating E-cadherin with a concomitant increase in Snail expression. 17-DMAG decreased expression of VEGF and HIF-1α while inhibiting cell migration and invasion. Conclusion Our data demonstrate that CoCl2 induced hypoxia promotes EMT and angiogensis, which are inhibited by 17-DMAG. These results suggest that hypoxia induced EMT and angiogensis is Hsp90 dependent in ESCC.

Sesamin exerts anti‐tumor activity in esophageal squamous cell carcinoma via inhibition of TRIM44 and NF‐κB signaling

Tripartite motif-containing 44 (TRIM44) is known to play an oncogenic role in multiple human cancers, including esophageal cancer. Sesamin possesses potent anti-inflammatory and anti-cancer properties for various cancers. This study is designed to unravel the biological functions of sesamin and TRIM44 in esophageal cancer. TRIM44 expression in esophageal squamous cell cancer (ESCC) cell lines and tissues was determined by RT-qPCR assay and Western blot. The effects of sesamin and TRIM44 on ESCC cell growth in vivo and in vitro were assessed by the mouse model and CCK-8 assay, respectively. We found that TRIM44 was significantly upregulated in ESCC cell lines and tissues when compared to their counterparts. Sesamin treatment or depletion of TRIM44 markedly reduced ESCC cell proliferation. The nuclear factor kappa B (NF-κB) and toll-like receptor 4 (TLR4) signaling pathway may be involved in sesamin-mediated TRIM44 suppression. Finally, we showed that oral administration of sesamin dramatically inhibited tumor growth or ESCC in nude mice. Our results suggest that sesamin exerts anti-tumor activity in ESCC via inhibition of NF-κB signaling pathway, demonstrating its potential for the treatment of esophageal cancer.

MiR-550a-3/NFIC plays a driving role in esophageal squamous cell cancer cells proliferation and metastasis partly through EMT process.

In this study, the functional role of miR-550a-3 and its direct target nuclear factor IC (NFIC) in esophageal squamous cell cancer (ESCC) cells were explored. Differential expression of miR-550a-3 in ESCC tissues was acquired from TCGA database, and Kaplan-Meier method was used to determine the relationship between miR-550a-3 expression and survival time of ESCC patients. Expression level of miR-550a-3 in several ESCC cell lines was measured by qRT-PCR. Two cell lines including Eca109 and JAR were used to perform proliferation, cloning, invasion and migration experiments. Targeted relationship between miR-550a-3 and NFIC was speculated by predication software and confirmed by dual luciferase assay. Additionally, potential relationship between miR-550a-3 and NFIC was analyzed by Spearman rank correlation analysis and western blot. Rescue assays were performed to explore the function of miR-550a-3/NFIC in ESCC cells biological behaviors. Expression levels of key proteins involved in epithelial-to-mesenchymal transition (EMT) process were determined by western blot. By consulting TCGA database, we found that high expression of miR-550a-3 was positively connected with the poor prognosis of patients with ESCC. In addition, overexpression of miR-550a-3 promoted the proliferation, colony formation and metastasis of ESCC cells. Moreover, rescue assays revealed that overexpression of NFIC attenuated the promoting effects of miR-550a-3 on ESCC cells malignant behaviors. While the promoting effects of miR-550a-3 on EMT process were inhibited by NFIC. Our results illustrate the importance of miR-550a-3/NFIC in regulation of ESCC cells growth and metastasis, which could contribute to developing novel target for early diagnosis or neoteric therapeutic target for ESCC.

Long noncoding RNA SNHG12 suppresses esophageal squamous cell carcinoma progression through competing endogenous RNA networks.

Esophageal squamous cell cancer (ESCC) has high rates of recurrence and mortality. Small nucleolar RNA host gene 12 (SNHG12) is known to promote the progression of several cancers. Therefore, we aimed to investigate the expression and role of SNHG12 in ESCC. The expression and clinical value of SNHG12 in esophageal cancer were explored using data from The Cancer Genome Atlas (TCGA) and the online server GEPIA. Real-time quantitative polymerase chain reaction (qRT-PCR) was used to verify the expression levels of SNHG12 in ESCC tissues and cell lines. Furthermore, loss-of-function assays were performed to examine the effect of SNHG12 on ESCC cells in vitro and in vivo. The potential competing endogenous RNA networks of SNHG12 in ESCC were explored. SNHG12 was downregulated in human ESCA tissues compared to control tissues. The expression of SNHG12 was strongly associated with T stage, N stage, and TNM stage. Low SNHG12 expression in esophageal tumor tissues was significantly correlated with poor prognosis. Furthermore, knockdown of SNHG12 not only promoted proliferation, colony formation, migration, and invasion and inhibited apoptosis in ESCC cells in vitro, but also increased tumor growth in vivo. Additionally, this proves that the SNHG12/miRNA-195-5p/BCL9 network might be involved in ESCC. This is the first study to reveal that SNHG12 is downregulated in ESCC tissues and could be used as a prognostic tool. SNHG12 suppressed tumor progression in ESCC cells, serving as a potential biomarker. The SNHG12/miRNA-195-5p/BCL9 network is proposed to be the mechanism leading to ESCC progression.

Activated STAT3 Could Reduce Survival in Patients with Esophageal Squamous Cell Carcinoma by Up-regulating VEGF and Cyclin D1 Expression

Signal transduction and activators of transcription factor (STAT) 3 is associated with a poor prognosis in certain types of cancer. The purpose of the present study was to investigate the clinical and prognostic significance of STAT3/p-STAT3 expression in esophageal squamous cell cancer (ESCC) patients. A total of 71 patients were enrolled in the study. STAT3 and p-STAT3 expression were detected by Western Blot and immunohistochemistry assays. Stattic, the STAT3 inhibitor, was used to block the activation of STAT3 in ESCC cell lines Eca-109 and Kyse-30, and the CCK8 assay was performed to detect the effect of Stattic on the viability of ESCC cells. The expression of associated genes was assessed by RT-PCR and Western blot at RNA and protein levels, respectively. STAT3 expression was correlated with infiltration degree (pT) and pTNM. And p-STAT3 expression was correlated with pT, lymphatic metastasis (pN) and pTNM. The expression of VEGF, Bcl-xl and Cyclin D1 was up-regulated in ESCC tissues and positively correlated with p-STAT3 level, besides Bcl-xl. In vitro, Stattic inhibited the viability of Eca-109 and Kyse-30 cells in a dose- and time- dependent manner, and significantly inhibited the expression of VEGF, Bcl-xl and CyclinD1 at mRNA and protein level. The 5-year survival rate of the 71 patients was significantly associated with pT, pN, pTNM stage, p-STAT3 level, VEGF expression and Cyclin D1 expression. pN and p-STAT3 expression were independent relevant factors. Our results showed that p-STAT3 might serve as an essential biomarker for tumor invasion and metastasis in ESCC.

Circular RNA hsa_circ_0000654 promotes esophageal squamous cell carcinoma progression by regulating the miR-149-5p/IL-6/STAT3 pathway.

Circular RNAs (circRNAs) are novel noncoding RNAs (ncRNAs) with covalently closed-loop structures that play an essential regulatory role in diverse malignancies, including esophageal squamous cell cancer (ESCC). Circ_0000654 expression in ESCC and its mechanism of action remains unclear. Real-time PCR (RT-PCR) was employed to detect circ_0000654 and miR-149-5p expression in ESCC tissues. Circ_0000654 and miR-149-5p expression in ESCC cells was selectively regulated. Furthermore, interleukin 6 (IL-6) and signal transducer and activator of transcription 3 (STAT3) expression in cells was detected by RT-PCR and western blot analysis, while CCK8, BrdU, flow cytometry, and transwell assays were used to monitor cell proliferation, apoptosis, migration and invasion, respectively. The dual-luciferase reporter assay and RIP assay were used to verify the targeting relationship between circ_0000654 and miR-149-5p, miR-149-5p and IL-6. The function of circ_0000654 on ESCC cell proliferation and metastasis in vivo was examined using a subcutaneous xenograft model and a tail intravenous injection model in nude mice. Circ_0000654 was significantly upregulated in ESCC tissues and cell lines, and its high expression was remarkably associated with an increased T stage and local lymph node metastasis in ESCC patients. Circ_0000654 overexpression and knockdown experiments revealed that circ_0000654 regulated ESCC cell proliferation, migration, invasion, and apoptosis in vitro. Circ_0000654 was identified as a sponge of miR-149-5p and facilitated ESCC progression by indirectly activating the IL-6/STAT3 signaling pathway. Additionally, knocking down circ_0000654 strikingly repressed ESCC growth and metastasis in vivo. In summary, circ_0000654 functions as an oncogenic circRNA in ESCC and accelerates ESCC progression via adsorbing miR-149-5p and activating the IL-6/STAT3 signaling pathway.

Yes-associated protein (YAP) predicts poor prognosis and regulates progression of esophageal squamous cell cancer through epithelial-mesenchymal transition.

The impact of yes-associated protein (YAP) on the prognosis of patients with esophageal squamous cell cancer (ESCC) and its mechanism of action has seldom been reported. In the present study, the role of YAP on the prognosis of patients with ESCC and the mechanism of action of YAP in promoting the progression of ESCC was investigated. Tumor tissue samples from patients with ESCC were collected and the level of YAP expression was detected using immunohistochemical staining. In addition, YAP was knocked-down in ESCC cell lines and the effects on cell migration and invasion were examined. The expression levels of vimentin, N-cadherin, and E-cadherin were further investigated to examine the association between YAP and epithelial-mesenchymal transition (EMT). Results showed that overexpression of YAP was associated with larger lymph node metastasis and poor disease-free survival and overall survival. Compared with patients in early stage ESCC, the association was more significant in patients with late stage ESCC. Univariate and multivariate analyses further indicated that YAP expression could be an independent prognostic factor for ESCC. Downregulation of YAP inhibited cell migration and invasion. Western blot analysis showed that when YAP was knocked down, expression levels of vimentin and N-cadherin were reduced, whereas that of E-cadherin was increased. In conclusion, the results indicates that YAP expression level could be a novel marker for predicting the prognosis of patients with ESCC, and YAP-promoted tumor migration and invasion might be through EMT in ESCC.

Abstract 2788: The interplay between tumor-cell derived FoxO1 and macrophage in the tumor microenvironment of esophageal squamous cell carcinoma

Abstract Introduction: Esophageal squamous cell cancer (ESCC) is the predominant histologic type in China with high incidence and mortality. FOXO1 is considered as a tumor suppressor in several cancers, but its role in tumor immunology still remain elusive. A better understanding of how FOXO1 mediates the secretion of downstream chemokines, such as CCL20, and thus its ability in regulating macrophage function would be of crucial for further investigation. Materials and Methods: Quantitative PCR and immunohistochemistry were used to study the expression of FoxO1 in clinical ESCC samples. The survival analysis was performed based on the result of tissue microarray and corresponding clinicopathological information. Stable foxo1-transfected cell lines were constructed in human ESCC cell lines, and ELISA, western blotting and Quantitative PCR were conducted to evaluate the expression of foxo1 and its downstream molecule CCL20. The subsets of macrophages were identified through Flow cytometry and qPCR. Results: The expression of FOXO1 was significantly upregulated in tumorous tissue when comparing to adjacent normal tissue and predicted a poor prognosis in ESCC patients. Besides, the analysis of TCGA database indicated that the markers of M2 macrophage were upregulated in foxo1-high expressing tumor tissues when compared with foxo1-low expressing tumor tissues. In vitro, we have successfully differentiated monocytic cell line THP-1 into macrophage M0, M1 and M2. The M1 and M2 markers (CD80, CD163 and CD68) were measured by flow cytometry, while their major cytokines (IL6, TNF-α, CCL17, CCL18, IL1β and IL10) were detected by qPCR. The ELISA, western blot and qPCR results showed that the expression of CCL20 was upregulated in foxo1-high expressing tumor cells when compared to negative control. The migration assay showed that ESCC cells transfected with foxo1 could recruit more M2 macrophages when compared with foxo1-low expression ESCC cells and the effect was diminished upon blockade with anti-CCL20 neutralizing antibody in tumor cells. Besides, we found out that M2 macrophage could promote the migration and EMT of tumor cells by using M2 conditioned medium. Conclusions: FoxO1 displays an important role in M2 macrophage migration through the modulation of CCL20. This increased CCL20 reported in ESCC may become specific molecular/cellular processes operative in the TME of ESCC patients. Note: This abstract was not presented at the meeting. Citation Format: Ying Wang, Xinyuan Guan, Woon Ngar Kam. The interplay between tumor-cell derived FoxO1 and macrophage in the tumor microenvironment of esophageal squamous cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2788.

MiR-92a-3p promotes the proliferation, migration and invasion of esophageal squamous cell cancer by regulating PTEN.

Esophageal squamous cell cancer (ESCC) has a high mortality rate. MicroRNA (miR)-92a-3p is considered to be a tumor promotor and an oncomiR. The aim of the present study was to investigate the effect of miR-92a-3p and its target gene on ESCC in terms of proliferation, migration and invasion. Higher expression of miR-92a-3p was detected in the tissues of patients with ESCC, compared with that in normal tissues. In addition, ESCC cell lines had a higher expression of miR-92a-3p compared with normal esophageal cells. A miR-92a-3p mimic was found to promote ESCC cell proliferation and a miR-92a-3p inhibitor was found to reduce ESCC cell proliferation. miR-92a-3p mimic transfection accelerated ESCC cell migration and invasion and decreased ESCC cell apoptosis via the Bax/Bcl-2 pathway and cleaved caspase-3. Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) was detected as a target of miR-92a-3p by a dual luciferase reporter assay. The overexpression of PTEN not only inhibited ESCC proliferation, migration and invasion, but also promoted ESCC cell apoptosis. PTEN and the miR-92a-3p mimic inhibited and promoted ESCC proliferation, respectively, which may be associated with the PI3K/Akt pathway. The results of the study revealed that miR-92a-3p promoted the proliferation, migration and invasion of ESCC, and the effect of miR-92a-3p on ESCC was realized by regulating PTEN.

MicroRNA‑675‑3p promotes esophageal squamous cell cancer cell migration and invasion.

Esophageal cancer ranks fourth in cancer-associated mortality in China and the incidence of esophageal adenocarcinoma has risen dramatically over the past two decades. MicroRNA (miRNA/miR) serves a pivotal role in human cancer cell growth, invasion and migration. MiR-675-3p is highly expressed in esophageal squamous cell cancer (ESCC) tissues, and may have an influence on ESCC cell migration and invasion. ESCC tumor tissue samples from 35 patients were profiled. MiR-675-3p expression was confirmed by reverse transcription-quantitative polymerase chain reaction. Manipulation of miR-675-3p via knockdown was carried out with subsequent evaluation of effects on cell proliferation, invasion, migration, and use of western blotting and ELISA assays. MiR-675-3p was overexpressed in ESCC tissues compared with normal tissues, and had higher expression levels in ESCC cells compared with the healthy esophageal epithelial cell line. The results revealed a predominant upregulation of cell migration and invasion ability. MiR-675-3p inhibitor inhibited ESCC cell proliferation, migration and invasion ability. It was also demonstrated that downregulation of miR-675-3p decreased the levels of matrix metalloproteinase (MMP) 2 and 9 and increased the level of E-cadherin. In addition, the effects of miR-675-3p inhibitor on ESCC cell lines were eliminated by con-transfection with miR-675-3p inhibitor and miR-675-3p mimic. In conclusion, the results indicated that miR-675-3p may be involved in the progression of ESCC through regulating ESCC cell migration and invasion capacity via modulating epithelial mesenchymal transition markers (MMP2, MMP 9 and E-cadherin).

Downregulation of BIRC5 inhibits the migration and invasion of esophageal cancer cells by interacting with the PI3K/Akt signaling pathway.

As a mitotic spindle checkpoint gene, baculoviral IAP repeat containing 5 (BIRC5) serves pivotal roles in the development of various types of malignant tumors. In the present study, the expression of BIRC5 in patients with different stages of esophageal squamous cell cancer (ESCC) was investigated. The effect of BIRC5 on the migratory and invasive abilities of different ESCC cell lines was analyzed. Additionally, the effect of BIRC5 on the angiogenesis-associated factor vascular endothelial growth factor, brain-specific angiogenesis inhibitor 1 and methyl-CpG binding domain protein 2 was examined. In addition, the interaction between BIRC5 and the phosphatidylinositol 3-kinase (PI3K)/Akt pathway was analyzed. It was determined that BIRC5 is able to inhibit the migration and invasion of tumor cells, and regulate the expression of angiogenesis-associated factors. In addition, the PI3K/Akt signaling pathway is able to regulate the expression of BIRC5, which affects the development of ESCC.

Characterization of cluster of differentiation 47 expression and its potential as a therapeutic target in esophageal squamous cell cancer.

The increased expression of cluster of differentiation (CD)47 has been identified in a number of different tumor types and is recognized as an adverse prognostic factor that indicates an increased risk of mortality in patients. The binding of CD47 to signal regulatory protein α (SIRPα) inhibits the macrophage phagocytosis of tumor cells by triggering an inhibitory 'do not eat me' signal. This is one of the mechanisms used by tumor cells to evade immune surveillance. In the present study, CD47 levels and macrophage infiltration were assessed in patients with esophageal squamous cell cancer (ESCC). CD47-overexpressing ESCC cell lines were selected and human M2 macrophage phagocytic activity was measured. The results revealed that CD47 is highly expressed and macrophages are markedly infiltrated in cancerous tissue compared with non-cancerous tissue. High CD47 expression was detected in ESCC cell lines and the results of a phagocytosis assay indicated that human M2 macrophages phagocytized tumor cells in a dose-dependent manner following the blocking of CD47-SIRPα signaling by anti-CD47 antibodies. The results of the present study therefore support the use of anti-CD47 immunotherapy to treat patients with ESCC.

PTTG1 cooperated with GLI1 leads to epithelial-mesenchymal transition in esophageal squamous cell cancer.

Pituitary tumor-transforming gene-1 (PTTG1) could acquire its metastasis-promoting effects via inducing epithelial-mesenchymal transition (EMT). However, its role and mechanism in EMT in esophageal squamous cell cancer (ESCC) had not been clearly elucidated. Here, we demonstrated that PTTG1 was overexpressed in ESCC cell lines and tissues especially those with lymph node metastasis. Down regulation of PTTG1 levels dampened the ESCC cells invasion, migration, proliferation ability and colony formation in vitro and inhibited the growth of mouse xenograft model of ESCC cells in vivo. In addition, our in vitro and in vivo experiments consistently showed that decreased PTTG1 led to the inhibition of EMT process. Glioma-associated oncogene homolog1 (GLI1), a key factor in HH-GLI signaling pathway, was also overexpressed in ESCC cells and tissues. Mechanistic studies demonstrated that decreased PTTG1 mitigated the expression levels of GLI1 in vitro and in vivo and ChIP assay also indicated that PTTG1 cooperated with GLI1 by binding to its promoter. Furthermore, overexpression of GLI1 rescued the EMT inhibited by down regulation of PTTG1 in vitro. Together, these data suggested that PTTG1 promoted the invasion ability of ESCC cells via EMT, more important, PTTG1 participated in EMT via activating the expression of GLI1 in ESCC. PTTG1 could be a candidate biomarker for defining ESCC metastasis and useful target for therapy.