EC9706 Cells Research Articles

Inhibition of SALL4 reduces tumorigenicity involving epithelial-mesenchymal transition via Wnt/β-catenin pathway in esophageal squamous cell carcinoma.

BackgroundGrowing evidence suggests that SALL4 plays a vital role in tumor progression and metastasis. However, the molecular mechanism of SALL4 promoting esophageal squamous cell carcinoma (ESCC) remains to be elucidated.MethodsThe gene and protein expression profiles- were examined by using quantitative real-time PCR, immunohistochemistry and western blotting. Small hairpin RNA was used to evaluate the role of SALL4 both in cell lines and in animal models. Cell proliferation, apoptosis and invasion were assessed by CCK8, flow cytometry and transwell-matrigel assays. Sphere formation assay was used for cancer stem cell derivation and characterization.ResultsOur study showed that the transcription factor SALL4 was overexpressed in a majority of human ESCC tissues and closely correlated with a poor outcome. We established the lentiviral system using short hairpin RNA to knockdown SALL4 in TE7 and EC109 cells. Silencing of SALL4 inhibited the cell proliferation, induced apoptosis and the G1 phase arrest in cell cycle, decreased the ability of migration/invasion, clonogenicity and stemness in vitro. Besides, down-regulation of SALL4 enhanced the ESCC cells’ sensitivity to cisplatin. Xenograft tumor models showed that silencing of SALL4 decreased the ability to form tumors in vivo. Furthermore, our study demonstrated that SALL4 played a vital role in modulating the stemness of ESCC cells via Wnt/β-catenin signaling pathway and in epithelial-mesenchymal transition.ConclusionsOur results revealed that SALL4 might serve as a functional marker for ESCC cancer stem cell, a crucial marker for prognosis and an attractive candidate for target therapy of ESCC.

Activation of PPARγ suppresses proliferation and induces apoptosis of esophageal cancer cells by inhibiting TLR4-dependent MAPK pathway.

Although substantial studies on peroxisome proliferator-activated receptor γ (PPARγ) have focused on the mechanisms by which PPARγ regulates glucose and lipid metabolism, recent reports have suggested that PPARγ shows tumorigenic or antitumorigenic effects. The roles and mechanisms of PPARγ activation in esophageal cancer remain unclarified. EC109 and TE10 esophageal cancer cells were treated with 0, 10, 20 and 40 mM of PPARγ agonist rosiglitazone (RGZ) for 24, 48, and 72 h, and the cell viability and apoptosis were detected using methyl thiazolyl tetrazolium (MTT) assay and Flow cytometric (FCM) analysis, respectively. Moreover, the effects of inhibition of PPARγ by antagonist or specific RNA interference on cell viability, apoptosis, the Toll-like receptor 4 (TLR4) and mitogen-activated protein kinase (MAPK) pathways were evaluated. Additionally, the effect of TLR4 signaling on the MAPK pathway, cell viability and apoptosis was assessed. The results showed that RGZ suppressed proliferation and induced apoptosis of esophageal cancer cells, which could be partly restored by inactivation of PPARγ. RGZ suppressed the MAPK and TLR4 pathways, and the inhibitory effect could be counteracted by PPARγ antagonist or specific RNA interference. We also suggested that MAPK activation was regulated by the TLR4 pathway and that blocking the TLR4 and MAPK pathways significantly suppressed proliferation and induced apoptosis of esophageal cancer cells. In conclusion, our data suggested that activation of PPARγ suppressed proliferation and induced apoptosis of esophageal cancer cells by inhibiting TLR4-dependent MAPK pathway.

Insights into anticancer activity and mechanism of action of a ruthenium(II) complex in human esophageal squamous carcinoma EC109 cells

A ruthenium(II) complex [Ru(p-cymene)(NHC)Cl2] (NHC=1,3-bis(4-(tert-butyl)benzylimidazol-2-ylidene), referred to as L-4, has been designed and synthesized recently in order to look for new anticancer drugs with high efficacy and low side effects. The anticancer activity and mechanism of action of L-4 in human esophageal squamous carcinoma EC109 cells were systematically investigated. The results revealed that L-4 exerted strong inhibitory effect on the proliferation of EC109 cells, and it arrested EC109 cells at G2/M phase, accompanied with the up-regulation of p53 and p21 and the down-regulation of cyclin D1. The results also showed that the reactive oxygen species (ROS)-dependent apoptosis of EC109 can be induced by L-4 via inhibiting the activity of glutathione reductase (GR), decreasing the ratio of glutathione to oxidized glutathione (GSH/GSSG), and leading to the generation of reactive oxygen species. The mitochondria-mediated apoptosis of EC109 induced by L-4 was also observed from the increase of Bax/Bcl-2 ratio, overload of Ca2+, disruption of mitochondrial membrane potential (MMP), redistribution of cytochrome c, and activation of caspase-3/-9. However, the effects of L-4 on the cell viability, GR activity, GSH/GSSG ratio, reactive oxygen species level, mitochondria dysfunction and apoptosis induction were remarkably attenuated by adding the reactive oxygen species scavenger, NAC. Therefore, it was concluded that L-4 can inhibit the proliferation of EC109 cells via blocking cell cycle progression and inducing reactive oxygen species-dependent and mitochondria-mediated apoptosis. These findings suggested that the ruthenium(II) complex might be a potential effective chemotherapeutic agent for human esophageal squamous carcinoma (ESCC) and worthy of further investigation.

LncRNA UCA1 inhibits esophageal squamous-cell carcinoma growth by regulating the Wnt signaling pathway

ABSTRACTEsophageal squamous-cell carcinoma (ESCC) is one of the most common tumors worldwide. Recent studies suggested that long noncoding RNAs (lncRNAs) might play a key role in regulating cellular processes and cancer progression. One of the lncRNAs, urothelial carcinoma associated 1 (UCA1), is known to be dysregulated in several cancers, including bladder carcinoma, colorectal, melanoma, breast, gastric, and ESCC. However, contributions of UCA1 to ESCC remain largely undiscovered. In order to understand the role and mechanisms underlying UCA1 in ESCC, the association of UCA1 expression with risk of esophageal cancer development was determined in 106 esophageal cancer tissues of ESCC patients and adjacent normal tissues using real-time reverse-transcription polymerase chain reaction (PCR). The relative expression of UCA1 was significantly reduced in cancer versus adjacent normal tissues suggesting an enhanced risk of esophageal cancer. To investigate the biological functions of UCA1 in ESCC, it was of interest to examine whether overexpression of UCA1 might influence cell proliferation, apoptosis, cell cycle distribution, migration, and invasion in vitro using EC109 cells. Our results demonstrated that UCA1 decreased cell proliferation, migration, invasion, and cell cycle progression of EC109 cells. Further, mRNA microarray analysis of overexpressed UCA1 in EC109 cells revealed that abnormal expression of UCA1 also inhibited the Wnt signaling pathway. Gene levels of DKK1 were elevated while C-myc fell significantly in overexpressed UCA1 EC109 cells. Interestingly, Western blot demonstrated no significant differences in relative expression of CTNNB1 (β-catenin) but marked reduction in β-catenin (active form) levels in both total and nuclear proteins. These results suggest that UCA1 may inhibit ESCC growth by regulating the Wnt signaling pathway. In conclusion, UCA1 may be a novel biomarker involved in ESCC development that may provide a potential therapeutic target for ESCC.

Downregulation of cell division cycle 25 homolog C reduces the radiosensitivity and proliferation activity of esophageal squamous cell carcinoma

Radiation therapy is one of the most important methods of contemporary cancer treatment. Cells in the G2 and M phases are more sensitive to radiation therapy, and cell division cycle 25 homolog C (CDC25C) is essential in shifting the cell cycle between these two phases. In this study, the knockdown of CDC25C in human esophageal squamous carcinoma EC9706 cells was mediated by transfecting shRNA against human CDC25C-subcloning into pGV248. The levels of CDC25C mRNA and protein expression were assessed by reverse transcription–polymerase chain reaction (RT-PCR) and western blotting, respectively. Moreover, cell proliferation and radiosensitivity were measured. Stable CDC25C-knockdown EC9706 cell lines were successfully established. Furthermore, the proliferation of both control and CDC25C-shRNA-EC9706 cells was inhibited after the cells were treated with increasing X-ray doses, and the proliferation of the control cells was affected more significantly (p<0.05). Moreover, cell colony formation assays allowed us to reach the same conclusion. Taken together, our experiments demonstrated that the knockdown of CDC25C can reduce both the radiotherapy sensitivity and the proliferation activity of EC9706 cells. Thus, CDC25C might be a potential biomarker for radiotherapy treatment.

UBE2D3 gene overexpression increases radiosensitivity of EC109 esophageal cancer cells in vitro and in vivo.

Ubiquitin-conjugating enzyme E2D3 (UBE2D3), a key component in ubiquitin (Ub) proteasome system, plays a crucial role in tumorigenesis. We previously found that it is bound to hTERT, and UBE2D3 could attenuate radiosensitivity of human breast cancer cells. Here we investigated a contributing role of UBE2D3 in radiosensitivity of esophageal squamous carcinoma. We demonstrated that the overexpression of UBE2D3 in esophageal squamous carcinoma cells (EC109) resulted in prolonged G1 phase and shortened G2/M phase after irradiation. UBE2D3 overexpression also decreased length of telomere and activity of telomerase. In addition, the overexpression of UBE2D3 increased mRNA expression but decreased protein levels of hTERT in both vitro and vivo systems. Compared with untreated cells, the treatment of UBE2D3 overexpressing cells with the specific proteasome inhibitor (MG132) could up-regulate hTERT. MG132 treatment of UBE2D3 overexpressed cells caused a clear and dramatic increase in the amount of ubiquitinated hTERT species. These findings indicate that UBE2D3 enhances radiosensitivity of EC109 cells by degradating hTERT through the ubiquitin proteolysis pathway.

Effects of siRNA-Mediated Knockdown of HDAC1 on the Biological Behavior of Esophageal Carcinoma Cell Lines.

BackgroundHDAC1 has been shown to be closely associated with the occurrence of tumors. We aimed to investigate the effects of siRNA-mediated HDAC1 knockdown on the biological behavior of esophageal carcinoma cell lines.Material/MethodsHDAC1 expression in esophageal cancer cell lines TE-1, Eca109, and EC9706 was compared by Western blot analysis. These cells were transfected with siRNA-HDAC1 and cell proliferation was evaluated by MTT assay to select the optimum cell line for subsequent experiments. The effects of siRNA-HDAC1 on the migration and invasion of the selected cell line were assessed by transwell assay. The expression of cell cycle-related proteins cyclinD1, p21 and p27, and epithelial-mesenchymal transition (EMT)-related protein zonula occludens-1 (ZO-1), E-cadherin and vimentin was determined by Western blot analysis.ResultsHDAC1 expression in TE-1, Eca109 and EC9706 cells was significantly higher compared with normal esophageal cell line HEEC (P<0.01). MTT assay, Western blot and RT-PCR analyses demonstrated that the inhibitory effects of siRNA on HDAC1 expression and cell viability in TE-1 cells were the highest among all cell lines, which was therefore used in subsequent experiments. After TE-1 cells were transfected with siRNA-HDAC1, their migration and invasion were significantly lower compared with the controls (P<0.01). CyclinD1 and vimentin expression was significantly lower compared with the controls (P<0.01), whereas the expression of p21, p27, ZO-1 and E-cadherin was significantly higher (P<0.01).ConclusionsThe siRNA-mediated HDAC1 knockdown significantly inhibited the proliferation, migration and invasion of TE-1 cells probably by regulating the expression of cell cycle- and EMT-related proteins.

Exogenous hydrogen sulfide exerts proliferation, anti-apoptosis, angiopoiesis and migration effects via activating HSP90 pathway in EC109 cells.

Hydrogen sulfide (H2S) participates in diverse physiological and pathophysiologic processes of cancer both invitro and invivo. We have previously reported the proliferation/anti-apoptosis/angiogenesis/migration effects of exogenous H2S on liver cancer and glioma via amplifying the activation of NF-κB and p38MAPK/ERK1/2-COX-2 pathway. However, the effects of H2S on EC109 esophageal cells remain unclear. The present study demonstrated the effects of exogenous H2S on cancer cell growth via activating HSP90 pathways in EC109 esophageal cells. EC109 esophageal cells were treated with 400µmol/l NaHS (a donor of H2S) for 24h. The expression levels of HSP90, bcl-2, caspase-3, bax and MMP-2 were detected by western blot assay. Cell viability was detected by Cell Counting Kit-8 (CCK-8). The migration rate was analyzed using a Transwell migration assay and ImageJ software. NaHS promoted cell proliferation, as evidenced by an increase in cell viability. In addition, NaHS treatment reduced apoptosis, as indicated by the increased bcl-2 expression and decreased cleaved caspase-3 and bax expression. Importantly, exposure of NaHS increased the expression of MMP-2, the migration rate and expression of VEGF. Notably, co-treatment of EC109 cells with NaHS and GA (an inhibitor of HSP90 pathway) largely suppressed the aforementioned NaHS-induced effects. The findings of the present study provided novel evidence that HSP90 pathway was involved in NaHS-induced cancer cell proliferation, anti-apoptosis, angiopoiesis and migration in EC109 esophageal cells.

Tanshinone ⅡA inhibits human esophageal cancer cell growth through miR-122-mediated PKM2 down-regulation

Pyruvate kinase M2 (PKM2) plays a pivotal role in the growth, survival and metabolic reprogramming of cancer cells. Here, we presented for the first time that tanshinone ⅡA inhibited human esophagus cancer cell growth through miR-122-mediated PKM2 down-regulation pathway. Tanshinone ⅡA inhibited cell proliferation and induced cell cycle arrest in S phase in human Ec109 cells. As expected, tanshinone ⅡA down-regulated PKM2 mRNA and protein expression in Ec109 cells. Given these findings, we further investigated microRNAs regulation of PKM2 and confirmed miR-122 for targeting PKM2. Moreover, we found that tanshinone ⅡA-induced up-regulation of miR-122 expression inhibited PKM2 expression in Ec109 cells. Meanwhile, tanshinone ⅡA inhibited proliferation through miR122-medated PKM2 down-regulation. It was demonstrated that the anticancer activity of tanshinone ⅡA was targeted at metabolic regulation of miR-122/PKM2 in human esophagus cancer cells. Taken together, our results revealed tanshinone ⅡA targeting at PKM2-mediated metabolic reprogramming play an important role in inhibition of esophageal cancer cell growth.

Synthesis, characterization and anticancer activity of kaempferol-zinc(II) complex

According to the previous studies, the anticancer activity of flavonoids could be enhanced when they are coordinated with transition metal ions. In this work, kaempferol-zinc(II) complex (kaempferol-Zn) was synthesized and its chemical properties were characterized by UV–VIS, FT-IR, 1H NMR, elemental analysis, electrospray mass spectrometry (ES-MS) and fluorescence spectroscopy, which showed that the synthesized complex was coordinated with a Zn(II) ion via the 3-OH and 4-oxo groups. The anticancer effects of kaempferol-Zn and free kaempferol on human oesophageal cancer cell line (EC9706) were compared. MTT results demonstrated that the killing effect of kaempferol-Zn was two times higher than that of free kaempferol. Atomic force microscopy (AFM) showed the morphological and ultrastructural changes of cellular membrane induced by kaempferol-Zn at subcellular or nanometer level. Moreover, flow cytometric analysis indicated that kaempferol-Zn could induce apoptosis in EC9706 cells by regulating intracellular calcium ions. Collectively, all the data showed that kaempferol-Zn might be served as a kind of potential anticancer agent.

Bit1 knockdown contributes to growth suppression as well as the decreases of migration and invasion abilities in esophageal squamous cell carcinoma via suppressing FAK-paxillin pathway.

BackgroundThere is growing evidence that Bit1 exerts different roles in the development and progression of human cancers. Although Bit1 was highly exhibited in ESCC tissues in our previous study, its roles and molecular mechanisms implicated in development and progression of ESCC remain unknown.MethodsBit1 protein expression in ESCC cell lines and normal esophageal epithelial cell was detected by Western blotting. Bit1 protein expression mediated by Bit1 shRNA was investigated by Western blotting. MTT, migration assay, invasion experiment, ELISA and Flow cytometry were utilized to determine the effects of Bit1 knockdown on cell proliferation, migration, invasion and apoptosis, respectively. A xenograft model was used to examine in vivo tumourigenicity, and immunohistochemistry and TUNEL were utilized to evaluate the related protein expression and apoptosis. Gene microarray was determined by Agilent SurePrint G3 Human GE 8 × 60 K Microarray, the interaction of Bit1 and FAK proteins were detected by Immunoprecipitation and the key protein expressions of FAK-paxillin pathway were detected by Western blotting.ResultsWe found Bit1 expression in all human ESCC cell lines tested was significantly higher than that in normal esophageal epithelial cell Het-1A (P < 0.05), in which EC9706 presented the highest Bit1 level. Bit1 protein level was significantly downregulated at day 1 after transfection with specific shRNA against Bit1 (P < 0.05). At days 2 and 3, Bit1 level reached the lowest value after transfection with Bit1 shRNA. Moreover, Bit1 depletion contributed to growth inhibition in vitro and in vivo, reduced cell migration and invasion abilities, and induced cell apoptosis in EC9706 and TE1 cells. More importantly, Bit1 downregulation significantly lowered Bcl-2 and MMP-2 levels in EC9706 xenografted tumor tissues, meanwhile triggered apoptosis after treatment with different doses of Bit1 shRNA. Further gene microarray revealed that 23 genes in Bit1-RNAi group were markedly downregulated, whereas 16 genes were obviously upregulated. Notably, Bit1 intrinsically interacted with FAK protein in EC9706 cells. Moreover, paxillin was downregulated at mRNA and protein levels in Bit1 shRNA group, coupled with the decreases of FAK mRNA and protein expressions.ConclusionBit1 may be an important regulator in cell growth, apoptosis, migration and invasion of ESCC via targeting FAK-paxillin pathway, and thereby combinative manipulation of Bit1 and FAK-paxillin pathway may be the novel and promising therapeutic targets for the patients with ESCC.

Overexpression of UBE2D3 gene in esophageal carcinoma cell line EC109 can influence the proliferation, migration and the sensitivity to cisplatin

Objective To establish a stable transfection of UBE2D3 gene in esophageal carcinoma cell line EC109, and investigate the gene overexpression effects of migration, proliferation, and the sensitivity to cisplatin in the cell line. Methods pEGFP-C1 and pEGFP-UBE2D3 plasmids were transfected into the esophageal carcinoma EC109 strain. G418 screening method was used to select stably transfected cell lines which were named as control group (NC) and overexpression group (OE), respectively. The expression efficiency was verified by RT-PCR and Western blotting, the migration was evaluated by scratch test, and the proliferation and sensitivity of cells to cisplatin were respectively determined by CCK-8 assay and half maximal inhibitory concentration (IC50). Results Relative to EC109 cells, the mRNA expression of UBE2D3 of NC group was 1.010±0.590, that of OE group was 2.026±0.898. The protein expression of UBE2D3 of NC group was 0.923±0.237, OE group was 1.520±0.487, respectively. The expression of mRNA and protein level of UBE2D3 in NC was similar to that in EC109 cells (t=1.005, P>0.05; t=1.492, P>0.05), while that in OE was much higher than both above (t=6.682, P<0.05; t=9.150, P<0.05). The migration length of NC group was (0.161±0.062)mm at 12 h, while that of OE group was (0.052±0.007)mm (t=4.370, P<0.05). The migration length of NC group was (0.309±0.071)mm at 24 h, compared with OE group was (0.074±0.012)mm (t=3.644, P<0.05). At 12 h and 24 h, relative to NC group, the migration length of OE group was 0.236±0.051 and 0.241±0.037, respectively, which pointed out that the migration of OE was significantly lower than that of NC. For the 1st day, the proliferation of OE was 0.713±0.220 compared with that in NC (t=13.466, P<0.05), and it was 0.848±0.241 (t=27.241, P<0.05) and 0.742±0.233 (t=15.107, P<0.05) at the 2nd day and 3rd day, respectively. The IC50 of OE group was 0.356±0.154 (t=4.326, P<0.05) relative to that of NC by disposing with cisplatin at the 1st day, it was 0.445±0.098 (t=5.870, P<0.05) and 0.481±0.096 (t=5.009, P<0.05) at the 2nd day and 3rd day, respectively. The IC50 of OE group was less than that of NC group; when deposed with 5 μg/ml cisplatin, both proliferation of OE and NC group was slower than before. At the 1st day, 2nd day and 3rd day, the proliferation of OE group was 0.606±0.283 (t=8.872, P<0.05), 0.759±0.089 (t=16.771, P<0.05) and 0.569±0.574 (t=7.885, P<0.05) relative to NC group, respectively. Moreover, relative to NC group, fraction surviving of OE group was 0.831±0.323 (t=24.226, P<0.05), 0.875±0.102 (t=33.541, P<0.05) and 0.853±0.359 (t=28.187, P<0.05) at those time points above, respectively. The proliferation of OE was slower compared with that in NC, and the inhibition efficiency of cisplatin on the proliferation of OE was more significant than that of NC. Conclusion UBE2D3 gene overexpressed in esophageal carcinoma cell line EC109 strain may result in the cell′s phenotype inhibition of the migration and proliferation and enhance its sensitivity to cisplatin. Key words: Esophageal neoplasms; Cell movement; Cell proliferation; UBE2D3 gene

Over expression of p21-activated kinase 7 associates with lymph node metastasis in esophageal squamous cell cancers.

p21-activated kinase 7 is a member of the group II p21-activated kinase (PAK) family which is known to play important role in tumorigenesis and metastasis. However, the expression of p21-activated kinase 7 in esophageal squamous cell cancers and the correlation with clinical parameters has never been investigated. To explore the role of p21-activated kinase 7 in esophageal squamous cell cancers. Esophageal squamous cell carcinoma samples were collected and the expression of p21-activated kinase 7 was detected by immunohistochemistry. In vitro cell invasion assay was employed in EC9706 cells and EC9706PAK7 cells. Metastasis related genes were evaluated by Real-time PCR and Western Blot. In 85 samples, 44 (51.8%) samples showed strong expression and expression of PAK7 was significantly correlated with lymph node stage (p= 0.013) and TNM stage (p= 0.041). In vitro invasion assay showed that the invasion ability of EC9706 PAK7 cells increased 2.5 folds compared with EC9706 cells. PAK7 could enhance the protein levels of Vimentin and MMP10, but reduce E-cadherin, TIMP1 and TIMP2. PAK7 is overexpressed in human esophageal squamous cell cancer samples and correlated with lymph node metastasis.

Icariin displays anticancer activity against human esophageal cancer cells via regulating endoplasmic reticulum stress-mediated apoptotic signaling.

In this study, we investigated the antitumor activity of icariin (ICA) in human esophageal squamous cell carcinoma (ESCC) in vitro and in vivo and explored the role of endoplasmic reticulum stress (ERS) signaling in this activity. ICA treatment resulted in a dose- and time-dependent decrease in the viability of human EC109 and TE1 ESCCs. Additionally, ICA exhibited strong antitumor activity, as evidenced by reductions in cell migration, adhesion, and intracellular glutathione (GSH) levels and by increases in the EC109 and TE1 cell apoptotic index, Caspase 9 activity, reactive oxygen species (ROS) level, and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity. Furthermore, ICA treatments upregulated the levels of ERS-related molecules (p-PERK, GRP78, ATF4, p-eIF2α, and CHOP) and a pro-apoptotic protein (PUMA) and simultaneously downregulated an anti-apoptotic protein (Bcl2) in the two ESCC cell lines. The downregulation of ERS signaling using eIF2α siRNA desensitized EC109 and TE1 cells to ICA treatment, and the upregulation of ERS signaling using thapsigargin sensitized EC109 and TE1 cells to ICA treatment. In summary, ERS activation may represent a mechanism of action for the anticancer activity of ICA in ESCCs, and the activation of ERS signaling may represent a novel therapeutic intervention for human esophageal cancer.

Y-box-binding protein 1 promotes tumor progression and inhibits cisplatin chemosensitivity in esophageal squamous cell carcinoma.

Y-box-binding protein 1 (YB-1) has been identified as a pleotropic oncoprotein in multiple human malignancies and is involved in the regulation of various DNA/RNA-dependent events, including transcription and translation. However, little is known about expression pattern and underlying functions of YB-1 in esophageal squamous cell carcinoma (ESCC). In this study, we report that up-regulated YB-1 is closely correlated with TNM stage and tumor size in ESCC specimens and predicts a poor prognosis in ESCC patients. Genetic silencing of YB-1 inhibits cell proliferation and invasive potential by regulating its targeted genes associated with tumor growth and metastasis. In particular, we also show that silencing of YB-1 enhances chemotherapy-induced cytotoxicity in EC109 and TE-1 cells by targeting multidrug resistance 1 (MDR1). Our findings demonstrate the oncogenic roles of YB-1 in ESCC and support it as a target for ESCC therapy.

Knockdown of long non-coding RNA TP73-AS1 inhibits cell proliferation and induces apoptosis in esophageal squamous cell carcinoma.

Recent studies have shown that long non-coding RNAs (lncRNAs) are involved in a variety of biological processes and diseases in humans, including cancer. Our study serves as the first comprehensive analysis of lncRNA TP73-AS1 in esophageal cancer. We utilized a lncRNA microarray to analyze the expression profile of lncRNAs in esophageal squamous cell carcinoma. Our results show that lncRNA TP73-AS1 and BDH2 levels are generally upregulated in esophageal cancer tissues and are strongly correlated with tumor location or TNM stage in clinical samples. LncRNA TP73-AS1 knockdown inhibited BDH2 expression in EC9706 and KYSE30 cells, whereas BDH2 knockdown repressed esophageal cancer cell proliferation and induced apoptosis via the caspase-3 dependent apoptotic pathway. Overexpression of BDH2 in lncRNA TP73-AS1 knockdown cells partially rescued cell proliferation rates and suppressed apoptosis. In mouse xenografts, tumor size was reduced in lncRNA TP73-ASI siRNA-transfected tumors, suggesting that downregulation of lncRNA TP73-AS1 attenuated EC proliferation in vitro and in vivo. In addition, BDH2 or lncRNA TP73-AS1 knockdown enhanced the chemosensitivity of esophageal cancer cells to 5-FU and cisplatin. Our results suggest that lncRNA TP73-AS1 may be a novel prognostic biomarker that could serve as a potential therapeutic target for the treatment of esophageal cancer.

Synthesis and antitumor activity evaluation of lamiridosin A derivatives

A series of lamiridosin A derivatives were synthesized through simple procedures. Their antitumor activities were evaluated against EC9706, MGC803, and B16 cell lines in vitro. Several compounds showed potent antitumor activity, especially compound 10, with IC50 value of 2.36 μmol/L against MGC803 cell lines, is more potent than marketed positive drug 5-fluorouridine (5-FU).

Influence of Tanshinone IIA on the Apoptosis of Human Esophageal Ec-109 Cells

The induced-apoptosis effect and mechanism of human esophageal cancer Ec-109 cells via tanshinone IIA was investigated. The Ec-109 cells were cultured in vitro with different concentrations of tanshinone IIA (2 µg/mL, 4 µg/mL, or 8 µg/mL) for 12, 24, 36, and 48 hours. MTT assay was used to evaluate the proliferative inhibition rate of tanshinone IIA on esophageal Ec-109 cells. After 24 hours of culturing in vitro, a control group was assigned. The apoptosis rate was detected by the AO/EB and annexin V-FITC/propidium iodide assay, and the protein levels of Caspase-4 and CHOP were determined by the Western blot technique. MTT data showed that tanshinone IIA could significantly inhibit the proliferation of Ec-109 cells with a dose- and time-dependent mode. Compared with the control group, tanshinone IIA could apparently induce apoptosis of Ec-109 cells, and the level of Caspase-4 and CHOP (p < 0.01) obviously increased. Tanshinone IIA can significantly induce the apoptosis of Ec-109 cells, which may take effect by the stress pathway of the endoplasmic reticulum.

MiR-328 suppresses the survival of esophageal cancer cells by targeting PLCE1

Esophageal cancer (EC) is the sixth leading cause of death worldwide. Recent studies have highlighted the vital role of microRNAs (miRNAs) in EC development and diagnosis. In our study, qPCR analysis showed that miRNA-328 was expressed at significantly low levels in EC109 and EC9706 cells. The results also showed that overexpression of miR-328 by lentivirus-mediated gene transfer markedly inhibited cell proliferation and invasion, and enhanced apoptosis; whereas, inhibition of miR-328 significantly promoted cell proliferation and invasion, and suppressed apoptosis in EC109 and EC9706 cells. Dual-luciferase reporter assay confirmed that miR-328 directly targeted phospholipase C epsilon 1 (PLCE1) by binding to target sequences in the 3′-UTR. qPCR and Western blot analysis showed that the PLCE1 was overexpressed in EC109 and EC9706 cells. Additionally, we found that miR-328 overexpression decreased PLCE1 mRNA and protein levels, while miR-328 inhibition enhanced the PLCE1 expression. Further analysis showed that PLCE1 overexpression rescued the inhibitory effect of miR-328 on cell proliferation and invasion, and repressed the promotive effect of miR-328 on cell apoptosis. In conclusion, our results suggest that miR-328 suppresses the survival of EC cells by regulating PLCE1 expression, which might be a potential therapeutic method for EC.

Effect of SNX-2112 on proliferation of esophageal cancer cells via regulation of excision repair cross-complementing 1, epidermal growth factor receptor, and p53 expression.

SNX-2112 is a potential molecular targeted therapeutic drug against esophageal cancer (EC). However, its exact mechanism of action remains to be explained. The aim of this study was to investigate the effect of SNX-2112 on excision repair cross- complementing 1 (ERCC1), epidermal growth factor receptor (EGFR), and p53, to elucidate the mechanism of action of SNX-2112 on EC. Fresh tumor sections were surgically obtained from 65 patients with EC, and the expression of ERCC1, EGFR, and p53 was determined by immunohistochemical staining. Furthermore, the effect of SNX-2112 (0.2 μM) on the proliferation of EC-9706 cells and the expression of ERCC1, EGFR, and p53 in these cells were analyzed by a cell proliferation assay and western blot, respectively. We observed a significant decrease and increase in ERCC1 (P = 0.001) and p53 (P = 0.043) expression, respectively, and no significant difference in EGFR (P = 0.59) expression, with the TNM stage of EC, which suggested that ERCC1 and p53 could be potential markers for the TNM stage of EC. We also observed a significant increase in ERCC1 expression, and decrease in p53 and EGFR expression, in EC-9706 cells treated with SNX-2112 (P < 0.05), indicating the regulation of EC by SNX-2112. Furthermore, SNX-2112 treatment induced a significant decrease in the proliferation of EC-9706, which confirmed the function of SNX- 2112. In summary, SNX-2112 inhibits the proliferation of EC cells by regulating the expression of ERCC1, EGFR, and p53.