TE13 Cell Lines Research Articles

Retraction Note to: Slug down-regulation by RNA interference inhibits invasion growth in human esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is one of the most aggressive carcinomas of the gastrointestinal tract. We assessed the relevance of Slug in measuring the invasive potential of ESCC cells in vitro and in vivo in immunodeficient mice. We utilized RNA interference to knockdown Slug gene expression, and effects on survival and invasive carcinoma were evaluated using a Boyden chamber transwell assay in vitro. We evaluated the effect of Slug siRNA-transfection and Slug cDNA-transfection on E-cadherin and Bcl-2 expression in ESCC cells. A pseudometastatic model of ESCC in immunodeficient mice was used to assess the effects of Slug siRNA transfection on tumor metastasis development. The EC109 cell line was transfected with Slug-siRNA to knockdown Slug expression. The TE13 cell line was transfected with Slug-cDNA to increase Slug expression. EC109 and TE13 cell lines were tested for the expression of apoptosis-related genes bcl-2 and metastasis-related gene E-cadherin identified previously as Slug targets. Bcl-2 expression was increased and E-cadherin was decreased in Slug siRNA-transfected EC109 cells. Bcl-2 expression was increased and E-cadherin was decreased in Slug cDNA-transfected TE13 cells. Invasion of Slug siRNA-transfected EC109 cells was reduced and apoptosis was increased whereas invasion was greater in Slug cDNA-transfected cells. Animals injected with Slug siRNA-transfected EC109 cells exhihited fewer seeded nodes and demonstrated more apoptosis. Slug down-regulation promotes cell apoptosis and decreases invasion capability in vitro and in vivo. Slug inhibition may represent a novel strategy for treatment of metastatic ESCC.

FAT1 and PTPN14 Regulate the Malignant Progression and Chemotherapy Resistance of Esophageal Cancer through the Hippo Signaling Pathway.

Background Esophageal cancer (EC) is a common malignant tumor, which brings heavy economic burden to patients and society. Therefore, it is important to understand the molecular mechanism of recurrence, metastasis, and drug resistance of esophageal cancer. Methods Human esophageal cancer cell line TE13 (poorly differentiated squamous cell carcinoma) and normal human esophageal epithelial cell line het-1a were selected for aseptic culture. At the same time, 6 bottles of TE13 cell line were inoculated in logarithmic phase. Cell apoptosis was analyzed by flow cytometry (FCM). Cell clone formation assay was used to analyze the proliferation. Fibronectin-coated dishes were used to detect the characteristics of cell adhesion to extracellular matrix. The Transwell method was used to detect the cell invasion ability. Western blot was used to analyze the expression of Yap1, PTPN14, FAT1, and Myc. Results Results showed that FAT1 and PTPN14 were downregulated, while Yap1 was upregulated in esophageal cancer tissues. FAT1 inhibited the proliferation, adhesion, and invasion of human esophageal cancer cell lines, which might be associated with the upregulation of PTPN14 and the inhibition of Yap1 and Myc. Conclusion The results suggested that PTPN14 and FAT1 could regulate malignant progression and chemotherapy resistance of esophageal cancer based on the Hippo signaling pathway.

MiR-493 by regulating of c-Jun targets Wnt5a/PD-L1-inducing esophageal cancer cell development.

BackgroundEsophageal cancer is one of the most common cancers across the globe; the 5‐year survival of esophageal cancer patients is still low. MicroRNA (miRNA) dysregulation has been implicated in cancer development, and the miRNAs play a pivotal role in esophageal cancer pathogenesis. It is urgently needed to find out how miRNA dysregulation was involved in esophageal cancer (EC) development.MethodsThrough experiments in vivo and in vitro, we explored potential signaling pathways, miR‐493/Wnt5A/c‐JUN loop, in EC. Their mechanistic roles in EC cell proliferation, migration, and invasion were investigated through multiple validation steps in EC9706 and TE13 cell lines and EC specimens.ResultsOverexpression of miR‐493 attenuates esophageal cancer cell proliferation, migration, and invasion in vivo and in vitro. Moreover, miR‐493 downregulation is an unfavorable factor in EC and negatively correlated with Wnt5A. The existence of miR‐493 is also an important attribute of metabolism. Based on mechanism analyses, we show that miR‐493 inhibits the activity of c‐JUN and p‐PI3K/p‐AKT with enhanced p21 and directly regulates Wnt5A expression and function, whereas c‐JUN binds the promoter region of miR‐493 and suppressed the expression of miR‐493, forming a negative feedback loop.ConclusionsThe miR‐493/Wnt5A/c‐JUN loop is a molecular feedback loop that refers to the development of esophageal cancer cells and a potential target for the treatment of esophageal cancer.

X-linked inhibitor of apoptosis protein accelerates migration by inducing epithelial\u2013mesenchymal transition through TGF-\u03b2 signaling pathway in esophageal cancer cells

BackgroundThe prognosis of esophageal cancer is still dismal because of its high probability of metastasis that is likely related to the cellular process of epithelial–mesenchymal transition (EMT). Recent studies have shown a novel role of X-linked inhibitor of apoptosis protein (XIAP) in regulating the migration process of cancer cells and, therefore, linking to progression and poor prognosis of cancer.MethodsThe expression of XIAP in esophageal squamous cell cancer (ESCC) tissues was determined by immunohistochemistry assay. Cell migration was analyzed by wound healing assay and Transwell assay. The expression of EMT markers (E-cadherin, N-cadherin and Vimentin) was revealed by immunofluorescence assay. Quantitative real‑time PCR analysis and Western blot analysis were used to detect the expression of XIAP and EMT markers as well as transforming growth factor-β (TGF-β) at mRNA and protein level, respectively.ResultsWe found that the expression of XIAP closely correlated to the probability of lymphatic metastasis in patients and that ESCC patients with the high XIAP expression were associated with worse overall survival (OS). Univariate and multivariate analysis also revealed XIAP as an independent prognostic factor for overall survival in ESCC patients. In both EC9706 and TE13 cell lines, knockdown of XIAP decreased the migration of cancer cells by inhibiting EMT process through regulating the TGF-β signaling pathway, pinpointing a regulatory role of XIAP in migratory process upon TGF-β activation.ConclusionsTaken together, our results suggest XIAP as a important prognostic and regulative factor in ESCC patients. XIAP may promote migration of esophageal cancer cells through the activation of TGF-β mediated EMT.

Role of MiR-205/PTEN in cisplatin-resistant esophageal squamous cell carcinoma

Purpose: To evaluate the effect of miRNA-205 on cisplatin-resistant TE13 cell lines, and the interaction of miRNA-205 with downstream signaling pathway.Methods: TE13 cells were treated with cisplatin at a concentration of 1.5 μg/mL every 24 h for 3 months. Cisplatin-resistant cell lines were maintained in the continuous presence of 2 μg/ml cisplatin and supplemented every 72 h. Half-maximal inhibitory concentration (IC50) value was determined by MTT assay, and cell apoptosis was tested by flow cytometry. In addition, luciferase reporter assay was conducted to test the binding of miRNA-205 and phosphatase and tensin homologue deleted on chromosome 10 (PTEN) 3’UTR.Results: The cisplatin-resistant (cis-TE13) cell line was well established based on IC50 values (cis-TE13, IC50 = 2.215; TE13, IC50 = 0.304). The levels of miRNA-205, phosphatase, PTEN, and protein kinase B (p-AKT) were abnormally expressed in cis-TE13 cells. Overexpression of miRNA-205 significantly promoted cell viability and decreased cell apoptosis of cis-TE13 cells as indicated by IC50 values (cis-TE13, IC50 = 3.537; TE13, IC50 = 0.580). Moreover, miRNA-205 significantly activated p-AKT expression by inhibiting PTEN expression. In contrast to miRNA-205, PTEN overexpression inhibited cell viability, increased cell apoptosis of cis-TE13 cells (cis-TE13, IC50 = 2.625; TE13, IC50 = 0.246), decreased the expression of p-AKT, and counteracted the regulation of miRNA-205 (control, IC50 = 2.297; miR-205, IC50 = 4.693; miR-205+PTEN, IC50 = 2.011).Conclusion: These findings indicate that miRNA-205 exacerbates esophageal squamous cell via inhibition of PTEN expression, suggesting the potential value of miRNA-205 in thediagnosis or treatment of esophageal squamous cell carcinoma.Keywords: miRNA-205, PTEN, PI3K/AKT signaling pathway, Esophageal squamous cell, Carcinoma, Cisplatin resistance

Raltitrexed increases radiation sensitivity of esophageal squamous carcinoma cells

BackgroundRadiation therapy remains an important therapeutic modality, especially for those patients who are not candidates for radical resection. Many strategies have been developed to increase the radiosensitivity of esophageal cancer, with some success.MethodsThis study was conducted to determine whether raltitrexed can enhance radiosensitivity of esophageal squamous cell carcinoma (ESCC). ESCC cell lines 24 h were incubated with raltitrexed or DMSO with or without subsequent irradiation. Cell Counting Kit assay-8 assay and clonogenic survival assay were used to measure the cell proliferation and radiosensitization, respectively. Flow cytometry was utilized to examine cell apoptosis and cell cycle distribution in different groups. Immunofluorescence analysis was performed to detect deoxyribonucleic acid (DNA) double-strand breaks. In addition, the expression levels of proteins that are involved in radiation induced signal transduction including Bax, Cyclin B1, Cdc2/pCdc2, and Cdc25C/pCdc25C were examined by western blot analysis.ResultsThe results indicated that raltitrexed enhanced radiosensitivity of ESCC cells with increased DNA double-strand breaks, the G2/M arrest, and the apoptosis of ESCC cells induced by radiation. The sensitization enhancement ratio of 1.23–2.10 was detected for ESCC cells with raltitrexed treatment in TE-13 cell line. In vitro, raltitrexed also increased the therapeutic effect of radiation in nude mice.ConclusionRaltitrexed increases the radiosensitivity of ESCC. This antimetabolite drug is promising for future clinical trials with concurrent radiation in esophageal cancer.

Foretinib Enhances the Radiosensitivity in Esophageal Squamous Cell Carcinoma by Inhibiting Phosphorylation of c-Met.

As a crucial event involved in the metastasis and relapse of esophageal cancer, c-Met overexpression has been considered as one of the culprits responsible for the failure in patients who received radiochemotherapy. Since c-Met has been confirmed to be pivotal for cell survival, proliferation and migration, little is known about its impact on the regulation of radiosensitivity in esophageal cancer. The present study investigated the radiosensitization effects of c-Met inhibitor foretinib in ECA-109 and TE-13 cell lines. Foretinib inhibited c-Met signaling in a dose-dependent manner resulting in decreases in the cell viability of ECA-109 and TE-13. Pretreatment with foretinib synergistically prompted cell apoptosis and G2/M arrest induced by irradiation. Moreover, decreases ability of DNA damage repair was also observed. In vivo studies confirmed that the combinatorial use of foretinib with irradiation significantly diminishes tumor burden compared to either treatment alone. The present findings implied a crucial role of c-Met in the modulation of radiosensitization in esophageal cancer, and foretinib increased the radiosensitivity in ECA-109 and TE-13 cells mainly via c-Met signaling, highlighting a novel profile of foretinib as a potential radiosensitizer for the treatment of esophageal cancer.

Effects and its mechanism of Nimotuzumab on radiosensitivity of esophageal carcinoma ECA-109 and TE-13 cell lines

Objective: To investigate the effects of nimotuzumab on radiosensitivity of ECA-109 and TE-13 esophageal carcinoma cell lines and explore its possible mechanism. Methods: The ECA-109 and TE-13 cells were divided into control group, irradiation group, medicine group, and combined group (irradiation + medicine). In the combined group, ECA-109 and TE-13 cells were treated with nimotuzumab for 24 h before irradiation, and the cells were collected 2 h after irradiation. The radiosensitizing effects of nimotuzumab on ECA-109 and TE-13 cells were evaluated by clone formation assay. Cell apoptosis was detected by flow cytometry. Western blotting was used to evaluate the expression of EGFR, p-EGFR, DNA-PKcs, p-DNA-PKcs and γH2AX. Results: The values of Dq (quasithreshold dose), D0(mean lethal dose)and SF2 (surviving fraction at 2 Gy) of ECA-109 and TE-13 cells in the combined group were significantly lower than those of the radiation group (for ECA-109 cells, 1.11 vs. 1.72, 1.40 vs. 2.14, 0.42 vs. 0.66, respectively; for TE-13 cells, 0.41 vs. 0.46, 0.43 vs. 0.65, 0.40 vs. 0.71, respectively (all P<0.05). The sensitivity enhancement ratio (SER) of ECA-109 and TE-13 cells were 1.35 and 1.43, respectively. Flow cytometry showed that the apoptosis rate of ECA-109 and TE-13 cells in the combined group were significantly higher than those of the radiation group [for ECA-109 cells, (41.31±1.52)% vs. (9.54±0.52)%; for TE-13 cells, (46.28±0.28)% vs. (11.32±0.31)%, both P<0.01]. Western blotting showed that the expression levels of EGFR and DNA-PKcs were not significantly different in all groups (all P>0.05). Compared with those of the control group, p-EGFR and p-DNA-PKcs of the radiation group were significantly higher in both cell lines (P<0.05), and the γH2AX levels in the radiation group and medicine group were significantly higher than that of the control group (P<0.05). Compared with those of the radiation group and medicine group, p-EGFR and p-DNA-PKcs protein expression in the combined group were decreased significantly (P<0.05), while γH2AX protein expression was significantly increased (P<0.05). Conclusions: Nimotuzumab can enhance the radiosensitivity of esophageal cancer ECA-109 and TE-13 cells. The potential mechanism may be related to the inhibition of EGFR phosphorylation and down-regulation of DNA damage repair proteins. The radiosensitizing effect of nimotuzumab is greater on poorly differentiated esophageal cancer cells.

RASSF5A, a candidate tumor suppressor, is epigenetically inactivated in esophageal squamous cell carcinoma.

As a result of alternative splicing and differential promoter usage, RASSF5 exists in at least three isoforms (RASSF5A-RASSF5C), which may play different roles in tumorigenesis. The present study was to detect the role of RASSF5A, B and C in esophageal squamous cell carcinoma (ESCC) and clarify the critical CpG sites of RASSF5A, in order to clarify more information on the role of RASSF5 with regard to the pathogenesis of ESCC. Frequent silencing of RASSF5A but not RASSF5B and RASSF5C were found in esophageal cancer cell lines and the silencing of RASSF5A may be reversed by 5-Aza-dC or TSA treatment. The aberrant CpG island 1 methylation of RASSF5A induces silencing of its expression in TE13 cell line. Decreased mRNA and protein expression of RASSF5A was observed in ESCC tumor tissues and was associated with RASSF5A CpG island 1 methylation status. Unlike RASSF5A, expression variation of RASSF5B and RASSF5C was not found in ESCC tissues. Aberrant promoter methylation of RASSF5C was also not found in ESCC. RASSF5A methylation and protein expression were independently associated with ESCC patients' survival. These data indicated that the inactivation of RASSF5A through CpG island 1 methylation may play an important role in ESCC carcinogenesis, RASSF5A may be a functional tumor suppressor and may serve as a prognostic biomarker for ESCC.

Aberrant methylation and decreased expression of the TGF-β/Smad target gene FBXO32 in esophageal squamous cell carcinoma.

F-box protein 32 (FBXO32) (also known as atrogin-1), a member of the F-box protein family, has recently been identified as a transforming growth factor beta (TGF-β)/Smad target gene involved in regulating cell survival, and it may be transcriptionally silenced by epigenetic mechanisms in some kinds of carcinomas, yet its role in esophageal squamous cell carcinoma (ESCC) has not been defined. The role of FBXO32 in ESCC and the correlation of FBXO32 methylation with a series of pathologic parameters were studied in a large cohort of patients with ESCC. Decreased messenger RNA (mRNA) expression and protein expression of FBXO32 were observed in esophageal cancer cell lines, and the silencing of FBXO32 could be reversed by treatment with 5-aza-2'-deoxycytidine or trichostatin A in the TE13 cell line. In addition, aberrant methylation of FBXO32 and histone deacetylation was capable of suppressing FBXO32 mRNA and protein expression in TE13 cells. Decreased mRNA and protein expression of FBXO32 was observed in ESCC tumor tissues and was associated with FBXO32 promoter methylation status. A positive correlation between FBXO32 and phosphorylated SMAD family members 2 and 3 expression and Smad4 protein expression also was observed in clinical specimens. FBXO32 methylation status and protein expression were independently associated with survival in patients with ESCC. FBXO32 may be a functional tumor suppressor. Its inactivation through promoter methylation could play an important role in ESCC carcinogenesis, and reactivation of the FBXO32 gene may have therapeutic potential and might be used as a prognostic marker for patients with ESCC.

Decreased expression of RASSF1A and up-regulation of RASSF1C is associated with esophageal squamous cell carcinoma.

The Ras-Association Domain Family 1 (RASSF1) gene, which is located on the small arm of chromosome 3, contains two CpG islands and generates seven transcripts (RASSF1A-RASSF1G) by differential promoter usage and alternative splicing. As the main transcript, RASSF1A, B and C may play different roles in tumorigenesis. The present study was to detect the role of RASSF1A, B and C in esophageal squamous cell carcinoma (ESCC) and clarify the critical CpG sites of RASSF1A, in order to clarify more information on the role of RASSF1 with regard to the pathogenesis of ESCC. Frequent silencing of RASSF1A but not RASSF1B and RASSF1C were found in esophageal cancer cell lines and the silencing of RASSF1A may be reversed by 5-Aza-dC treatment. The aberrant promoter and exon 1 especially exon 1 methylation of RASSF1A induces silencing of its expression in TE13 cell line. Decreased mRNA and protein expression of RASSF1A was observed in ESCC tumor tissues and was associated with RASSF1A promoter and exon 1 methylation status. Unlike RASSF1A, methylation and expression variation of RASSF1B was not found in ESCC tissues. However, RASSF1C is highly expressed in ESCC tissues. RASSF1A methylation and protein expression were independently associated with ESCC patients' survival. These data indicated that the inactivation of RASSF1A through promoter and exon 1 methylation may play an important role in ESCC carcinogenesis and reactivation of RASSF1A gene may has therapeutic potential and may be used as a prognostic marker for ESCC patients.

The role of the retinoblastoma protein-interacting zinc finger gene 1 tumor suppressor gene in human esophageal squamous cell carcinoma cells.

The tumor suppressor protein retinoblastoma protein-interacting zinc finger gene 1 (RIZ1) is downregulated in several types of cancer, including esophageal squamous cell carcinoma (ESCC). The present study used two in vitro methods to re-express RIZ1 in the human ESCC TE13 cell line in order to induce apoptosis. RIZ1 was re-expressed in the TE13 cells by reintroducing the gene through transfection or by removal of transcriptional repression through treatment with a DNA methyltransferase (DNMT) inhibitor. To reintroduce the gene, the open reading frame of the RIZ1 gene was inserted into the eukaryotic expression pcDNA3.1(+) vector and pcDNA3.1(+)/RIZ1 was purified and transfected into the TE13 ESCC cells. Removing transcriptional repression involved treating the TE13 cells with 5-aza-2′-deoxycytidine (5-aza-CdR), a DNMT inhibitor. RIZ1 mRNA and protein expression were determined by quantitative polymerase chain reaction (qPCR) and western blotting. The rate of apoptosis of the cells was determined by flow cytometry. A recombinant eukaryotic human RIZ1 expression plasmid, pcDNA3.1(+)/RIZ1, was constructed and confirmed by sequencing. RIZ1 mRNA and protein expression increased in pcDNA3.1(+)/RIZ1 stably transfected cells. Treatment with 5-aza-CdR for 48 and 72 h resulted in increased RIZ1 protein expression and increased the rate of apoptosis in the TE13 cells (P<0.01). In conclusion, transfection of the TE13 cells with the eukaryotic pcDNA3.1(+)/RIZ1 expression vector and reversal of transcriptional repression of RIZ1 using 5-aza-CdR demonstrate that it is possible to re-express RIZ1 in TE13 cells. Furthermore, the re-expression of RIZ1 led to an increased rate of apoptosis and this method may provide new therapeutic possibilities.

Decreased Expression and Aberrant Methylation of Raf Kinase Inhibitory Protein Gene in Esophageal Squamous Cell Carcinoma

Raf kinase inhibitory protein (RKIP) gene is considered to be a suppressor of metastasis involved in various carcinomas. In the present study, we observed that promoter methylation repressed the expression of RKIP in TE-13 cell line. 5-Aza treatment and stable transfection of RKIP resulted in a significant inhibition of TE-13 cell proliferation. The promoter hypermethylation of RKIP was found to occur in dysplastic tissues and a close correlation was noted between RKIP methylation and the loss of mRNA and protein expression of the gene in ESCC specimens. In summary, RKIP may act as a tumor suppressor gene in esophageal cancer.

RETRACTED ARTICLE: Slug down-regulation by RNA interference inhibits invasion growth in human esophageal squamous cell carcinoma

BackgroundEsophageal squamous cell carcinoma (ESCC) is one of the most aggressive carcinomas of the gastrointestinal tract. We assessed the relevance of Slug in measuring the invasive potential of ESCC cells in vitro and in vivo in immunodeficient mice.MethodsWe utilized RNA interference to knockdown Slug gene expression, and effects on survival and invasive carcinoma were evaluated using a Boyden chamber transwell assay in vitro. We evaluated the effect of Slug siRNA-transfection and Slug cDNA-transfection on E-cadherin and Bcl-2 expression in ESCC cells. A pseudometastatic model of ESCC in immunodeficient mice was used to assess the effects of Slug siRNA transfection on tumor metastasis development.ResultsThe EC109 cell line was transfected with Slug-siRNA to knockdown Slug expression. The TE13 cell line was transfected with Slug-cDNA to increase Slug expression. EC109 and TE13 cell lines were tested for the expression of apoptosis-related genes bcl-2 and metastasis-related gene E-cadherin identified previously as Slug targets. Bcl-2 expression was increased and E-cadherin was decreased in Slug siRNA-transfected EC109 cells. Bcl-2 expression was increased and E-cadherin was decreased in Slug cDNA-transfected TE13 cells. Invasion of Slug siRNA-transfected EC109 cells was reduced and apoptosis was increased whereas invasion was greater in Slug cDNA-transfected cells. Animals injected with Slug siRNA-transfected EC109 cells exhihited fewer seeded nodes and demonstrated more apoptosis.ConclusionsSlug down-regulation promotes cell apoptosis and decreases invasion capability in vitro and in vivo. Slug inhibition may represent a novel strategy for treatment of metastatic ESCC.

Inhibitory effects of extracellular adenosine triphosphate on growth of esophageal carcinoma cells

To study the growth inhibitory effects of ATP on TE-13 human squamous esophageal carcinoma cells in vitro. MTT assay was used to determine the inhibition of proliferation of ATP or adenosine (ADO) on TE-13 cell line. The morphological changes of TE-13 cells induced by ATP or ADO were observed under fluorescence light microscope by acridine orange (AO)/ethidium bromide (EB) double stained cells. The internucleosomal fragmentation of genomic DNA was detected by agarose gel electrophoresis. The apoptotic rate and cell cycle after treatment with ATP or ADO were determined by flow cytometry. ATP and ADO produced inhibitory effects on TE-13 cells at the concentration between 0.01 and 1.0 mmol/L. The IC(50) of TE-13 cells exposed to ATP or ADO for 48 and 72 h was 0.71 or 1.05, and 0.21 or 0.19 mmol/L, respectively. The distribution of cell cycle phase and proliferation index (PI) value of TE-13 cells changed, when being exposed to ATP or ADO at the concentrations of 0.01, 0.1, and 1 mmol/L for 48 h. ATP and ADO inhibited the cell proliferation by changing the distribution of cell cycle phase via either G(0)/G(1) phase (ATP or ADO, 1 mmol/L) or S phase (ATP, 0.1 mmol/L) arrest. Under light microscope, the tumor cells exposed to 0.3 mmol/L ATP or ADO displayed morphological changes of apoptosis. A ladder-like pattern of DNA fragmentation was obtained from TE-13 cells treated with 0.1-1 mmol/L ATP or ADO in agarose gel electrophoresis. ATP and ADO induced apoptosis of TE-13 cells in a dose-dependent manner at the concentration between 0.03 and 1 mmol/L. The maximum apoptotic rate of TE-13 cells exposed to ATP or ADO for 48 h was 16.63% or 16.9%, respectively. ATP and ADO inhibit cell proliferation, arrest cell cycle, and induce apoptosis of TE-13 cell line.