EC9706 Cells Research Articles

Serotonin and its Functions as Gastrointestinal Hormone

Background: Serotonin plays the role of critical signal molecule in great number of physiologic processes and pathologic symptoms of gastrointestinal tract. As a gastrointestinal hormone serotonin takes place in the regulation of smooth muscle motor activity and glandular secretion. It affects the gastrointestinal sensation of pain, nausea and vomiting. The aim of our study is to determine the presence and localization of serotonin-producing EC cells and distribution of serotonin receptor 5-HTR3 in the human stomach.Material and methods: Biopsy specimens from 25 patients aged 40-70 years: body and antral part of the stomach are studied by immunohistochemical reactions for serotonin, serotonin receptor 5-HTR3; and transmission electron microscopy.Results: The serotonin-producing cells are found between columnar cells of gastric epithelium, in the fundic and pyloric glands of the gastric mucosa. Their ultrastructural characteristics show the presence of EC1 and EC2 enterochromaffin cells. The expression of serotonin receptor 5-HTR3 in covering epithelium, glandular and interstitial cells shows the possibility serotonin to affect gastric mucosa secretion. The intensive expression of 5-HTR3 receptors in gastric wall smooth muscle cells demonstrates the key role of serotonin in gastrointestinal motility.Conclusion: In order to obtain a better understanding of the functional role of serotonin, we investigate the localization of serotonin-producing EC cells, their ultrastructural characteristics and the presence and distribution of serotonin receptor 5HTR3 in the stomach. Enzymes needed for serotonin secretion and degradation, its transporters, as it great numbers of receptors are the base new drugs to be synthesized aiding clinical practice in gastroenterology.

HDAC2 regulates cell proliferation, cell cycle progression and cell apoptosis in esophageal squamous cell carcinoma EC9706 cells.

Increasing evidence has demonstrated that histone deacetylase 2 (HDAC2) participates in the regulation of a variety of biological processes in numerous tumors. However, the potential role of HDAC2 in the development and progression of esophageal squamous cell carcinoma (ESCC) remains elusive. Immunohistochemistry was utilized to detect the expression of HDAC2, Cell Counting Kit-8 was used to determine the cell proliferation, and flow cytometry was employed to investigate cell cycle and cell apoptosis. Finally, western blotting was employed to detect the protein expression of cyclin D1, p21, B cell lymphoma-2 (Bcl-2) and Bcl-2-associated X protein (Bax). The present study found that expression of HDAC2 protein in ESCC tissues was significantly increased compared with atypical hyperplasia tissues and normal esophageal mucosa (P<0.001). The expression of HDAC2 was not associated with the age or gender of patients (P>0.05), but was closely associated with the histological grade, invasion depth, tumor-node-metastasis stage and lymph node metastasis, respectively (all P<0.001). HDAC2 small interfering RNA effectively downregulated the expression of HDAC2 protein in ESCC EC9706 cells. Downregulation of HDAC2 expression evidently inhibited cell proliferation, arrested cell cycle at the G0/G1 phase and induced cell apoptosis in ESCC EC9706 cells, coupled with increased expression of p21 and Bax proteins and decreased expression of cyclin D1 and Bcl-2 proteins. Overall, the present findings suggest that HDAC2 may play an important role in the development and progression of ESCC and be considered as a novel molecular target for the treatment of ESCC.

Preparation and properties evaluation of a novel pH-sensitive liposomes based on imidazole-modified cholesterol derivatives

As a new kind of drug carries, pH-sensitive liposomes have been widely studied in tumor therapy for their advantages of target ability and sustained-release. Here, we synthesized a pH-sensitive material, N-(3-Aminopropyl)imidazole-cholesterol (IM-Chol) and prepared a novel pH-sensitive liposomes using IM-Chol and phosphatidylcholine. IM-Chol was synthesized through amidation reaction between the amino group of N-(3-Aminopropyl)imidazole and acyl chloride group of cholesteryl chloroformate in a weak base solution. Optimal conditions to prepare liposomes were obtained by the orthogonal experiment with the higher encapsulation efficiency as the evaluation indicator. The properties of liposomes, such as particle size, zeta potential, morphology, encapsulation efficiency, drug release behavior and in vitro cell toxicity were evaluated by transmission electron microscopy (TEM), dynamic light scattering (DLS) and MTT assay respectively. The results showed that the average particle size of IM-Chol liposomes was 141nm (PDI 0.323). Liposomes can assemble into uniform spheres at pH 7.4, but under the condition of pH 5.0, the spherical structure of IM-Chol liposomes was broken, exhibiting pH-sensitive property. In vitro drug releasing studies demonstrated the controlled-release behavior of the curcumin (CUR) in the IM-Chol liposomes. The cumulative release of CUR reached to 72.5% in the first 24h at pH 5.0, faster than that at pH 7.4, which confirmed that the drug carrier displayed pH-sensitive release behaviors. In addition, the MTT assay was employed to test the cytotoxicity of IM-Chol liposomes and CUR IM-Chol liposomes. All cell viabilities were greater than 80% after incubating for 24h, even up to the highest dose of 500mg/L, indicating that IM-Chol liposomes had good biocompatibility. The tumor inhibitory results towards EC109 cells of free CUR and CUR-loaded IM-Chol liposomes indicated that IM-Chol liposomes indeed enhanced the cell killing effect of CUR. These results showed that the novel IM-Chol liposomes prepared in this paper had pH-sensitive property and were expected to play a huge potential in tumor treatment.

Induction of the mitochondria-mediated apoptosis in human esophageal cancer cells by DS2, a newly synthetic diterpenoid analog, is regulated by Bax and caused by generation of reactive oxygen species.

Ent-kaurane diterpene compounds have attracted considerable attention in recent years due to its antitumor, antibacterial, and antiviral activities. However, the clinical development of natural kaurane diterpenes, for example, oridonin for cancer therapy has been hampered by its relatively moderate potency, limited bioavailability. Herein, we report a newly synthetic analog of natural ent-kaurane diterpene, DS2, which exhibits significantly improved activity of antiproliferation against various cancer cell lines relative to oridonin. DS2 treatment triggers the mitochondria-mediated apoptosis and cell cycle arrest in human esophageal cancer cell lines (EC9706, EC109). Interestingly, normal human esophageal epithelial cells (HEECs) and normal human liver cells (HL-7702) are both significantly more resistant to the growth inhibition by DS2 compared with esophageal cancer cells. The DS2-induced apoptosis in EC9706 cells correlated with the drop of mitochondrial membrane potential (MMP), release of cytochrome c into the cytosol and activation of caspase-9 and -3. The induction of proapoptotic proteins p21 and Bax were also observed in DS2-treated cells. The DS2-induced apoptosis was significantly attenuated by knockdown of Bax proteins. Meanwhile, the DS2 treatment caused generation of reactive oxygen species (ROS) in human esophageal cancer cells, but not in HEECs, which was attenuated by pretreatment with ROS scavenger N-acetylcysteine (NAC). More interestingly, the antioxidants pretreatment completely attenuated DS2 mediated loss of the MMP and apoptosis, as well as Bax expression and growth inhibition. In conclusion, the present study reveals that the mitochondria-mediated cell death by DS2 is associated with Bax regulation and ROS generation, and understanding the function and mechanism of DS2 will help us to design better anti-cancer drugs.

Overexpression of A613T and G462T variants of DNA polymerase β weakens chemotherapy sensitivity in esophageal cancer cell lines.

BackgroundHuman DNA polymerase β (polβ) is a small monomeric protein that is essential for short-patch base excision repair. It plays an important role in regulating the sensitivity of tumor cells to chemotherapy.MethodsWe evaluated the mutation of polβ in a larger cohort of esophageal cancer (EC) patients by RT-PCR and sequencing analysis. The function of the mutation was evaluated by CCK-8, in vivo tumor growth, and flow cytometry assays.ResultsThere are 229 patients with the polβ mutation, 18 patients with A613T mutation, 12 patients with G462T mutation among 538 ECs. Analysis results of survival time showed that EC patients with A613T, G462T mutation had a shorter survival than the others (P < 0.05). CCK-8 and flow cytometry assays results showed the A613T, G462T EC9706 cells were less sensitive than WT cells to 5-FU and cisplatin (P < 0.05). Experiments results in vivo showed that the tumor sizes of A613T and G462T group were larger than WT and polβ−/− groups (P < 0.05).ConclusionsIn this study, we discovered A to T point mutation at nucleotide 613 (A613T) and G to T point mutation at nucleotide 462 (G462T) in the polβ gene through 538 EC patients cohort study. A613T and G462T variant of DNA polymerase β weaken chemotherapy sensitivity of esophageal cancer.

KIAA1377 is associated with lymph node metastasis in esophageal squamous cell carcinoma.

KIAA1377, of which there are few studies regarding cell biology and neurological diseases, has been found to be significantly amplified in esophageal squamous cell carcinoma (ESCC) with lymph node metastasis compared with ESCC without lymph node metastasis. This suggests that KIAA1377 may play a role in the lymph node metastasis of ESCC. There has, to the best of our knowledge, been no study performed to investigate the role of KIAA1377 in ESCC. In the present study, the expression of KIAA1377 was detected by immunohistochemistry, and its expression was statistically analyzed with clinicopathological parameters, using commercially obtained tissue arrays consisting of 86 cases of ESCC and 79 paired controls. KIAA1377 was knocked down ex vivo using transient transfection with specific small hairpin RNA (shRNA) vectors into ESCC TE-1 and EC9706 cell lines whose endogenous KIAA1377 level was highest. The variation of proliferation, migration and invasion were evaluated using methyl thiazolyl tetrazolium, wound healing and Transwell assay, respectively. It was found in vivo that KIAA1377 expression was significantly associated with lymph node metastasis and differentiation, and ex vivo that knockdown of KIAA1377 cannot significantly affect proliferation and mobility in the ESCC cell line TE-1. Overall, this is the first study suggesting that KIAA1377 may play a role in the lymph node micrometastasis of ESCC.

Pro-Apoptotic Effects of JDA-202, a Novel Natural Diterpenoid, on Esophageal Cancer Through Targeting Peroxiredoxin I.

Esophageal cancer (EC) is an aggressive malignancy and the most common solid tumor of gastrointestinal tract all over the world, with high incidence in Asia. The current study was designed to investigate the anticancer efficacy and mechanism that is involved in the action of a natural ent-kaurene diterpenoid, JDA-202, targeting EC. We found that an antioxidant protein peroxiredoxin I (Prx I) was upregulated in human EC tissues as well as in EC cell lines. JDA-202, a novel natural compound isolated from Isodon rubescens (Labiatae), was proved to possess strong anti-proliferative activities on those cell lines. Importantly, JDA-202 does not only bind to Prx I directly and markedly inhibit the activity of Prx I in vitro, but it also significantly induces hydrogen peroxide (H2O2)-related cell death. Furthermore, overexpression of Prx I significantly reversed EC109 cell apoptosis caused by JDA-202, whereas short interfering RNA (siRNA)-induced Prx I knockdown resulted in marked cell death even without JDA-202 pretreatment. On the other hand, the increased phosphorylation of mitogen-activated protein kinase (MAPK) proteins (c-Jun N-terminal kinase [JNK], p38, and extracellular signal-regulated kinase [ERK]) by JDA-202 was suppressed by N-acetylcysteine (NAC) or catalase, a known reactive oxygen species (ROS) or H2O2 scavenger. JDA-202 also significantly inhibited the growth of EC109 tumor xenograft, without significant body weight loss and multi-organ toxicities. Innovation and Conclusion: Our findings, for the first time, demonstrated that JDA-202 may serve as a lead compound, targeting the overexpressed Prx I in EC cell lines and ROS accumulation as well as inhibiting the activation of their downstream targets in MAPKs. Antioxid. Redox Signal. 27, 73-92.

Design, synthesis and biological evaluation of [1,2,4]triazolo[1,5-a]pyrimidines as potent lysine specific demethylase 1 (LSD1/KDM1A) inhibitors

A new series of [1,2,4]triazolo[1,5-a]pyrimidine-based LSD1 inhibitors were designed, synthesized, and further evaluated for their cytotoxicity against MGC-803, EC109, A549 and PC-9 cells as well as the ability of inhibiting LSD1. Some of these compounds showed potent inhibition toward LSD1 and selectively inhibited growth of A549 and PC-9 cells. Compound 6l potently inhibited growth of PC-9 cells (IC50 = 0.59 μM), about 4-fold more potent than 5-FU. Further SARs studies led to the identification of compounds 6l-m, which had good growth inhibition against all the tested cancer cell lines and were much more potent than 5-FU and GSK2879552. Besides, compounds 5p, 5q and 6i inhibited LSD1 potently (IC50 = 0.154, 1.19 and 0.557 μM, respectively). Docking studies revealed that compound 5p formed arene-H interactions with Val333 and hydrogen bonds with surrounding Ala331, Met332, and Ala539 residues. Compound 5p significantly inhibited migration of A549 and PC-9 cells in a concentration-dependent manner, but had different effect on the expression of E-cadherin and N-cadherin. The [1,2,4]triazolo[1,5-a]pyrimidine scaffold may serve as a starting point for developing potent LSD1 inhibitors for cancer therapy.

RAD51 regulates CHK1 stability via autophagy to promote cell growth in esophageal squamous carcinoma cells.

The serine/threonine protein kinase CHK1 has been reported to bind to the recombinase RAD51 and facilitates its assembly in DNA damage sites via phosphorylation. However, the role of RAD51 in regulating the expression of CHK1 has never been explored. Here, we show that RAD51 is highly upregulated in esophageal squamous tumor tissues and its DMC1 domain significantly promotes cell growth of esophageal cancer (EC) cells through CHK1. To gain the mechanistic insights, firstly, in the presence of 3-methyladenine (3MA), an autophagy inhibitor, we found that the reduction of CHK1 and the inhibition of cell growth in RAD51-deficient EC109 cells were strikingly restored. Subsequently, the autophagy-related experiments revealed that RAD51 negatively participated in autophagy. Moreover, results from in vitro clonogenic survival assays showed that RAD51 depletion greatly enabled EC cells to resist the autophagy inhibitors 3MA and hydroxychloroquine (HCQ) treatments. Above all, our studies firstly highlight a direct role of RAD51 in autophagy process and characterize its functional domain in cell growth regulation. Moreover, our data firstly shed insights into the possible application of autophagy inhibitors in treating RAD51 overexpressed EC patients.

Effect of Food Additive Citric Acid on The Growth of Human Esophageal Carcinoma Cell Line EC109.

Today, esophageal cancer (EC) has become one of the most common cancer types in China. Therefore, new drug and therapeutic strategies are urgently needed to improve postoperative survival rate of patients with EC. As a food additive, several lines of evidence have shown that citric acid can be served as glycolysis suppressor to inhibit growth of some tumor cells. However, little is known about the effect of this organic acid on the growth of human esophageal carcinoma cell line, EC109. In this experimental study, cell proliferation rate was determined using MTT assay. Apoptotic morphological changes were evaluated by fluorescent microscopy using Hoechst 33258 staining. Cell apoptosis rate and mitochondrial membrane potential (MMP) were detected using flow-cytometry. Effect of citric acid on cellular membrane permeability was assessed by measuring lactate dehydrogenase (LDH) activity, using LDH assay kit. Compared to the control group, there was a marked decrease in cells proliferation when the cells were treated with higher citric acid concentrations (800, 1600 μg/ml). Typical apoptotic morphology of EC109 cells was observed upon treatment with citric acid, such as chromatin condensation and appearance of apoptotic body. Cell apoptotic indexes were significantly increased (P<0.01) after treatment with citric acid at the concentration of 400-1600 μg/ml. Extracellular LDH activity and loss of MMP in all of the treated groups were significantly higher than control (P<0.05), in a dose-dependent manner. These results suggest that citric acid prevents EC109 cell growth by inhibiting cell proliferation and inducing apoptosis, which perhaps offers some theoretical guidance for its application in EC treatment.

MiR-424-5p participates in esophageal squamous cell carcinoma invasion and metastasis via SMAD7 pathway mediated EMT.

BackgroundsESCC is a life-threatening disease due to invasion and metastasis in the early stage. Great efforts had been made to detect the molecular mechanisms which led to the invasion and metastasis in ESCC. Recent evidence had suggested that deregulation of miR-424-5p took an important role in cancers. However, its role and functional mechanism in ESCC had seldom been elucidated.MethodsThe expression levels of miR-424-5p were detected in ESCC tissues and cell lines by real-time PCR methods. Then, the invasion, metastasis and proliferation ability of ESCC cell lines transfected with miR-424-5p mimics were analyzed separately by transwell invasion assay, wound healing assay and cell proliferation assay. Finally, the target gene of miR-424-5p was studied and verified by luciferase activity assay. And the role of miR-424-5p in EMT was also investigated by real-time PCR and western blot assay.ResultsWe showed that the expression levels of miR-424-5p were decreased both in ESCC tissues and cell lines. Furthermore, the expression levels of miR-424-5p were negatively linked to lymph node metastasis in ESCC tissues. Restoration of miR-424-5p in EC-1 cells by using miR-424-5p mimics could decrease the invasion, metastasis and proliferation of EC-1 cells, indicating its role in inhibition on the invasion and metastasis ability of ESCC cells and tissues. In addition, we demonstrated that SMAD7 was a specific target gene for miR-424-5p by luciferase activity assay and miR-424-5p could not only negatively regulate SMAD7 expression but also participate in EMT via SMAD7, because overexpression of SMAD7 could partly enhance the miR-424-5p anti-EMT function.ConclusionsOur results described that miR-424-5p -SMAD7 pathway contributed to ESCC invasion and metastasis and up-regulation of miR-424-5p perhaps provided a strategy for preventing tumor invasion, metastasis.

Inhibition of miR-196a affects esophageal cancer cell growth in vitro.

Esophageal cancer (EC) is one of the most common causes of cancer-related mortality worldwide. Several oncogenes such as miR-196a have been implicated in the carcinogenesis and progression of EC. The purpose of this study was to determine the effects of anti-miR-196a on the growth and survival of human EC cells in vitro. We found that miR-196a was highly expressed in both TE1 and EC109 cells and that miR-196a knockdown inhibited cell proliferation and migration. Furthermore, miR-196a knockdown sensitized EC cells to radiation treatment and chemotherapy. Inhibition of miR-196a also altered cell cycle progression and induced G2/M arrest, which was related to changes in the levels of cyclin B1. ABCG2, which was highly expressed in untransfected EC cells, was inhibited by miR-196a knockdown. Thus, our results confirm the fact that miR-196a is highly involved in the biological behavior of EC progression in vitro. We conclude that miR-196a is a useful biological marker and potential therapeutic target for the clinical treatment of human EC.

Vanadate-induced antiproliferative and apoptotic response in esophageal squamous carcinoma cell line EC109

ABSTRACTVanadate is a transition element that present in nature and was shown to be a nonspecific inhibitor of protein tyrosine phosphatases. It was reported that vanadium (Vd) compounds exhibit antitumor actions in several cancer cell lines. This study aimed to examine the antiproliferative and apoptotic actions of different concentrations of sodium vanadate (NaVd) (+5) in esophageal squamous carcinoma cell line EC109 by determining the protein expression levels of cyclin D1 and caspase-3 following incubation for various times from 15 min up to 4 h. In addition, cell proliferation of EC109 treated with different concentrations (NaVd) was also measured using the MTT assay at 4, 12, 24, and 48 h. The cell cycle of EC109 cells exposed to different concentrations of NaVd was detected using flow cytometry determination at 24 h. Data showed that NaVd greater than 100 µM significantly increased cyclin D1. In contrast, reduced caspase-3 protein expression levels occurred at 50 µM. Cellular proliferation was significantly decreased at 50uM. The cell cycle was arrested at S phase with 100 µM NaVd. Taken together, data indicate that NaVd produced concentration- and time-dependent antitumor actions in EC109 cell line.

Structurally novel steroidal spirooxindole by241 potently inhibits tumor growth mainly through ROS-mediated mechanisms.

Cancer cells always have increased ROS levels, thus making them more vulnerable to persistent endogenous oxidative stress. The biochemical difference between cancer and normal cells could be exploited to achieve selective cancer cell killing by exogenous ROS-producing agents. Herein we described a structurally novel steroidal spirooxindole by241 and its anticancer efficacy. By241 exhibited potent inhibition against human cancer cells and less toxic to normal cells. By241 concentration-dependently induced apoptosis of MGC-803 and EC9706 cells, accompanied with the mitochondrial dysfunction and increased ROS levels. NAC can completely restore the decreased cell viability of MGC-803 cells caused by by241, suggesting ROS-mediated mechanisms. The expression levels of proteins involved in the mitochondrion-related pathways were detected, showing increased expression of proapoptotic proteins and decreased expression of anti-apoptotic proteins, and activation of caspases-9/-3, but without activating caspase-8 expression. Pretreatment with Z-VAD-FMK partially rescued by241-induced apoptosis of MGC-803 cells. Additionally, by241 inhibited mTOR, activated p53 and its downstream proteins, cleaved MDM2 and PI3K/AKT as well as NF-κB signaling pathway. In vivo experiments showed that by241 did not have significant acute oral toxicity and exerted good anticancer efficacy against MGC-803 bearing mice models. Therefore, by241 may serve as a lead for further development for cancer therapy.

5-Azacytidine suppresses EC9706 cell proliferation and metastasis by upregulating the expression of SOX17 and CDH1.

5-Azacytidine is a well-known anticancer drug that is clinically used in the treatment of breast cancer, melanoma and colon cancer. It has been reported that 5-azacytidine suppresses the biological behavior of esophageal cancer cells. However, corresponding mechanisms remain unclear. In this study, using Transwell invasion and cell proliferation assays, we demonstrated that 5-azacytidine significantly inhibited the metastasis and proliferation of EC9706 cells, and upregulated the expression of cadherin 1 (CDH1) and SRY-box containing gene 17 (SOX17). Moreover, the inhibition of the metastasis of the 5-azacytidine-treated EC9706 cells was impaired following transfection with siRNA targeting CDH1 (CDH1 siRNA), and the inhibition of cell proliferation was attenuated following the downregulation of SOX17 by siRNA targeting SOX17 (SOX17 siRNA). Furthermore, 5-azacytidine remarkably reduced the CDH1 and SOX17 promoter methylation levels, suggesting that 5-azacytidine upregulates the expression of SOX17 and CDH1 by inhibiting the methylation of the SOX17 and CDH1 promoter. The findings of our study confirm that 5-azacytidine suppresses the proliferation and metastasis of EC9706 esophageal cancer cells by upregulating the expression of CDH1 and SOX17. The expression levels of CDH1 and SOX17 negatively correlate with the promoter methylation levels. CDH1 and SOX17 are potential indicators of the clinical application of 5-azacytidine.

A novel domino approach for synthesis of indolyl tetrahydropyrano[4,3-c]pyrazole derivatives as anticancer agents

A series of indolyl substituted 1,4,6,7-tetrahydropyrano[4,3-c]pyrazole derivatives were synthesized via a domino method based on the 1,4:3,6-Dianhydrofructose. The mechanism was proposed and proved by calculation with a density functional theory (DFT), which includes formation of phenylhydrazone, furanone ring opening, Fischer indole synthesis, pyrazole ring closing and a furan ring expansion. In vitro antitumor activity of all synthesized compounds against four human cancer cell lines (MCF-7, EC-109, HGC-27, and PC-3 cell lines) were then evaluated, using MTT assay. We found that most of the compounds were more potent than the positive control 5-fluorouracil. Particularly, compound 4i against HGC-27 and PC-3, 4j against EC-109 cell lines showed three fold greater activity than 5-fluorouracil, respectively. The activity of compounds 4c and 4d against MCF-7 cell line was close to that of doxorubicin.

Abstract 3541: Targeting autophagy to enhance paclitaxel sensitivity in esophageal carcinoma

Abstract Esophageal cancer is one of the malignancies threatening human health with high incidence and a very low 5-year survival rate with poor outcomes in the developing countries. Chemotherapy has been played indispensable roles while companied with more and more chemoresistance and side effects. Numerous studies have shown that autophagy may play specific role as one of the drug resistance mechanisms through promoting cancer cell survival via self-digestion. Therefore targeting autophagy might be another promising approach of therapeutics in cancer. Paclitaxel(PTX) is widely used for malignant tumors treatment through inducing apoptosis and autophagy. More findings discovered that chemoresistance is still a major hurdle for PTX due to cytoprotective autophagy. In order to investigate whether targeting autophagy could confer the sensitivity of PTX in esophageal carcinoma, chloroquine (CQ) was applied as an autophagy inhibitor to study the esophageal carcinoma cells EC109 co-treated with PTX in vitro and explore the potential molecular mechanisms. Firstly, CQ and PTX were used separately and also combined to treat EC109 cells at different dosages and time points, and the MTT results showed that CQ could contribute to the suppressive effect of PTX on the growth and proliferation of EC109 cells. Meanwhile the migration and invasion abilities of EC109 were significantly inhibited by co-treatment of PTX and CQ comparing with PTX only through scratch test and cell invasion Transwell chamber test, moreover the combination treatment dramatically suppressed the colony formation on soft agar. Further investigation showed that mTOR pathway was activated in CQ or PTX exposure, which resulted in phosphorylated mTOR(p-mTOR) down-regulation, followed by the decline of phosphorylated p70S6K (p-p70S6K) and phosphorylated p-4EBP1, and the autophagy marker LC3I/II conversion and p62 elevated eventually, which indicated that autophagy was mediated in PTX or CQ treatment in EC109 cells. On the other hand, GFP-LC3 was transfected into EC109 cells to observe the LC3 translocation status after CQ or PTX treatment, which usually be regarded as the morphological maker of autophagy, and the results confirmed the findings in Western Blot. Most importantly, the combination treatment of CQ and PTX resulted in synergistic consequences. For further understanding the mTOR pathway was initiated in CQ or PTX mediated autophagy in this study, we used lentiviral shRNA embedding mTOR to knockdown the expression of mTOR first and then studied the signaling pathway changes after CQ and PTX co-treatment, and we found a decrease trend of LC3-II/ I ratio and p62 also compared with the competent mTOR control. From these results, we confirmed that autophagy would benefit the survival of EC109 cells, and our findings demonstrated that targeting of autophagy using CQ could be an effective and potential strategy to improve PTX treatment outcomes in the management of esophageal carcinoma. Citation Format: Jiajing Cai, Yan Cai, Qiang Ma, Jiang Zou, Binfeng He, Fan Chang, Lei Xu, Xiaolan Guo. Targeting autophagy to enhance paclitaxel sensitivity in esophageal carcinoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3541.

Inhibition of allicin in Eca109 and EC9706 cells via G2/M phase arrest and mitochondrial apoptosis pathway

The effects and underlying molecular mechanisms of allicin on oesophageal squamous cell carcinoma (ESCC) are unclear. Herein, we investigated the effect and action mechanism of allicin in the ESCC cells of Eca-109 and EC9706. The cell viability and invasion ability of the two ESCC cells in allicin group were significantly decreased after allicin treatment. Allicin reduced the percentage of G0/G1 and S phase and increased the population of G2/M phase in a dose-dependent manner. The expression levels were significantly increased for p53, p21, CHK1, and decreased for cyclinB after allicin treatment. The apoptotic rate was significantly increased and accompanied by Cyt c release from the mitochondria to the cytosol, as well as Bax, caspase-3 and cleaved caspase-9 which were significantly increased. Furthermore, suppression of tumour growth was evident in vivo. These results suggest that allicin can serve as a novel and effective anti-oesophageal cancer agent for the treatment of ESCC.

ATF3 suppresses ESCC via downregulation of ID1.

Esophageal cancer is one of the most prevalent forms of cancer and has a particularly high mortality rate due to early metastasis; however, the underlying mechanisms of its formation and progression remain unclear. The present study performed immunohistochemical analysis and observed that the expression of activating transcription factor 3 (ATF3) was reduced in esophageal squamous cell carcinoma (ESCC) in comparison with non-tumor adjacent tissues. By contrast, inhibitor of DNA binding 1 (ID1) was overexpressed in ESCC tissues, demonstrating an inverse correlation with ATF3 (P<0.01). In ESCC EC109 and KYSE450 cells lines, transfection with an ATF3-overexpression plasmid resulted in the inhibition of cell proliferation, motility and migration, which was associated with the induction of E-cadherin expression and inhibition of cyclin D1 and Twist. Notably, ATF3 exerted an inverse regulatory interaction with ID1. The results of the present study provide additional evidence of the tumor suppressive features of ATF3 and demonstrate a novel mechanism of ATF3-mediated inhibition of cancer metastasis in esophageal cancer.

Inhibitory effect of α-solanine on esophageal carcinoma in vitro.

α-solanine, a bioactive component and one of the major steroidal glycoalkaloids in potatoes, has been observed to inhibit growth and induce apoptosis in cancer cells. However, the antitumor efficacy of α-solanine on esophageal carcinoma has yet to be fully elucidated. In the present study, the antitumor efficacy of α-solanine against human esophageal carcinoma cells was investigated. It was determined that α-solanine inhibited the growth and proliferation of human esophageal EC9706 and Eca109 cancer cells in a dose-dependent manner, as well as the cell migration and invasion. In addition, the apoptotic rate was increased in the cancer cells treated with α-solanine in a dose-dependent manner, compared with that of the control group (P<0.05). The expression levels of tumor metastasis-related proteins, including matrix metalloproteinase (MMP)-2 and MMP-9, were reduced in the cells treated with α-solanine, as compared with the control group. Conversely, significantly higher expression levels of E-cadherin were detected in the α-solanine-treated groups, as compared with the control group (P<0.05). Therefore, the current results provide a novel insight into the anti-tumor mechanism of α-solanine, and suggest that α-solanine is a potential agent for the prevention and treatment of esophageal carcinoma.