Effects of down-regulation of HDAC6 expression on proliferation, cell cycling and migration of esophageal squamous cell carcinoma cells and related molecular mechanisms.

OBJECTIVE: To study the effects of down-regulation of HDAC6 expression on proliferation, cell cycling and migration of esophageal squamous cell carcinoma (ESCC) cells and related molecular mechanisms. METHODS: ESCC cell line EC9706 cells were randomly divided into untreated (with no transfection), control siRNA (transfected with control siRNA) and HDAC6 siRNA (transfected with HDAC6 small interfering RNA) groups. Effects of HDAC6 siRNA interference on expression of HDAC6 mRNA and protein in EC9706 cells were investigated by semi-quantitative RT-PCR, Western blotting and immunocytochemistry methods. Effects of down-regulation of HDAC6 expression on cell proliferation, cell cycle, and cell migration were studied using a CCK-8 kit, flow cytometry and Boyden chambers, respectively. Changes of mRNA and protein expression levels of cell cycle related factor (p21) and cell migration related factor (E-cadherin) were investigated by semi- quantitative RT-PCR and Western blotting methods. RESULTS: After transfection of HDAC6 siRNA, the expression of HDAC6 mRNA and protein in EC9706 cells was significantly downregulated. In the HDAC6 siRNA group, cell proliferation was markedly inhibited, the percentage of cells in G0/G1 phase evidently increased and the percentage of cells in S phase decreased, and the number of migrating cells significantly and obviously decreased. The mRNA and protein expression levels of p21 and E-cadherin in the HDAC6 siRNA group were significantly higher than those in the untreated group and the control siRNA group, respectively. CONCLUSIONS: HDAC6 siRNA can effectively downregulate the expression of HDAC6 mRNA and protein in EC9706 cells. Down-regulation of HDAC6 expression can obviously inhibit cell proliferation, arrest cell cycling in the G0/G1 phase and reduce cell migration. The latter two functions may be closely related with the elevation of mRNA and protein expression of p21 and E-cadherin.

Down-regulated miRNA-214 induces a cell cycle G1 arrest in gastric cancer cells by up-regulating the PTEN protein.

To detect the expression of miRNA-214 in human gastric cancer cell lines of BGC823, MKN45 and SGC7901, and to identify the effect of miRNA-214 on cell cycle and apoptosis of these cells. Expression of miRNA-214 in human normal gastric mucosal cell line GES-1 and human gastric cancer cell lines was detected by real-time reverse-transcription polymerase chain reaction. Antisense-miRNA-214 oligonucleotides were transfected transiently into gastric cancer cell lines to down-regulate the expression of miRNA-214. The cell cycle and apoptosis were studied by flow cytometry assay. PTEN, one of the target genes of miRNA-214 was detected by using of immunocytochemistry and Western blotting. MiRNA-214 was overexpressed in gastric cancer cell lines of BGC823, MKN45 and SGC7901 compared with normal gastric mucosal cell line GES-1. Antisense-miRNA-214 oligonucleotides significantly down-regulated the expression of miRNA-214, and increased the portion of G1-phase and decreased the portion of S-phase in BGC823 and MKN45 cells. The immunocytochemistry test and Western blotting analysis showed that the down-regulation of miRNA-214 could significantly up-regulate the expression of PTEN in BGC823 and MKN45 cells. MiRNA-214 is overexpressed in human gastric cancer cell lines of BGC823, MKN45 and SGC7901. The down-regulation of miRNA-214 could induce a G1 cell cycle arrest in them, the up-regulation of PTEN maybe one of the mechanism.

Reduced stratifin expression can serve as an independent prognostic factor for poor survival in patients with esophageal squamous cell carcinoma.

UNLABELLED: Stratifin plays an important role in cancer biology by interfering with intracellular signalling pathways and cell-cycle checkpoints. Decreased expression of stratifin gene has been reported to be a poor prognostic indicator in a variety of human malignant tumors. AIM: To clarify the role and prognostic significance of stratifin in esophageal squamous cell carcinoma (ESCC). METHODS: The alteration of stratifin messenger RNA (mRNA) and protein was analyzed by reverse-transcription and quantitative real-time polymerase chain reaction (QRT-PCR) and Western blotting in 20 paired ESCC and nonneoplastic esophageal mucosa tissues, respectively. Then, immunohistochemistry (IHC) was used to evaluate expression of stratifin in tissues of 148 ESCC patients (including the former 20 pairs of tissues) and correlate it with clinicopathological parameters and prognosis of ESCC patients. RESULTS: The stratifin level of mRNA and protein was markedly downregulated in ESCC tissue compared with in corresponding nonneoplastic esophageal epithelium (P<0.05). Similarly, the positive rate of stratifin protein expression was lower in the esophageal cancer than in paired nonneoplastic esophageal epithelium as detected by IHC (P=0.007). Statistically, the downregulation of stratifin expression was correlated with tumor infiltration depth (P=0.003), lymph node metastasis (P=0.008), distant metastasis (P=0.013), and lymphovascular invasion (P=0.007) of ESCC. Furthermore, the reduced stratifin expression was associated with shorter 5-year survival rate of ESCC patients after curative surgery (P<0.0001). On the basis of univariate and multivariate Cox regression analysis, we found that reduced stratifin expression, T4 stage, lymph node metastasis, and distant metastasis were independent risk factors for worse prognosis in ESCC patients. CONCLUSION: The present report indicates that stratifin could be a useful indicator for prognosis of this disease, as well as a potential target for more effective therapy.

Increased expression of prohibitin and its relationship with poor prognosis in esophageal squamous cell carcinoma.

Prohibitin, a potential tumor suppressor, has been shown to be an anti- proliferative protein, a regulator of cell-cycle progression and in apoptosis. Recently, it was found to be over-expressed in breast cancer and gastric cancer, and it has been suggested as a biomarker in those diseases. To clarify the role and the prognostic significance of prohibitin expression in esophageal squamous cell carcinoma (ESCC), we analyzed the expression in ESCC and their corresponding nonneoplastic epithelia tissues by immunohistochemistry(IHC), Western blotting and real-time quantitative reverse transcription polymerase chain reaction(QRT-PCR).The relationship between prohibitin expression and clinicopathological variables was examined by statistical analysis. The findings suggested the up-regulation of prohibitin play an important role in the carcinogenesis of ESCC. The over-expression of prihibitin was significantly correlated with the depth of tumor, lymph node metastasis, distant metastasis, lymphatic invasion and vascular invasion of ESCC. These results suggested that prohibitin(+), lymph node metastasis and distant metastasis could be the independent risk factors for worse prognosis in ESCC patients.

[Effect of ß-catenin gene silencing by shRNA on biologic characteristics of human esophageal carcinoma cells].

OBJECTIVE: To study the effects of short hairpin RNA (shRNA) mediated gene silencing of ß-catenin on the biological characteristics of esophageal carcinoma cells, and to provide theoretical and experimental evidence for the gene therapy of esophageal carcinoma through target inhibition of ß-catenin gene. METHODS: Single strand DNA was synthesized according to the hairpin RNA sequence, and then subcloned into eukaryotic expression vector pGenesil-3 to construct a shRNA-expression pDNAs driven by human U6 promoter of ß-catenin (pGen-3-CTNNB1). One additional construct of random siRNA (pGen-3-con) without homologous to any human genes was constructed in a similar fashion as control.Positive clones were identified and verified by restriction cleavage and DNA sequencing analyses. pGen-3-CTNNB1 and pGen-3-con were then transfected into esophageal carcinoma cell line Eca-109 with liposome, respectively. Positive colonies were selected with G418. Expression of ß-catenin protein and mRNA in the transfected and nontransfected Eca-109 cells were examined by Western blotting, immunofluorescence and RT-PCR, respectively. Xenograft tumor model was used to compare the tumorigenesis of three different cells.Expressions of ß-catenin in all tumor tissues were examined by immunohistochemistry staining. The invasive abilities of three different cells were examined with transwell invasion filter and Matrigel. RESULTS: ß-catenin expression levels were found markedly decreased in Eca-109 cells transfected with pGen-3-CTNNB1. In vivo, transfection with ß-catenin shRNA greatly impeded the tumor growth, pGen-3-con (1.18 ± 0.13) g, Eca-109 (1.38 ± 0.21) g, pGen-3-CTNNB1 (0.42 ± 0.09) g, P < 0.05. Immunohistochemistry staining showed a significantly decreased expression of ß-catenin in ß-catenin shRNA transfected cells than in random shRNA transfected and nontransfected cells (P < 0.05). The infiltration abilities of esophageal carcinoma cells were significantly suppressed, pGen-3-con (81 ± 5)/HPF, Eca-109 (77 ± 6)/HPF, pGen-3-CTNNB1 (41 ± 4)/HPF, P < 0.01; along with significantly decreased migration abilities, pGen-3-con (73 ± 5)/HPF, Eca-109 (69 ± 5)/HPF, pGen-3-CTNNB1 (38 ± 4)/HPF (P < 0.05). CONCLUSIONS: There are abnormal expression of ß-catenin and activation of Wnt signaling pathway in human esophageal carcinoma cell line Eca-109. RNA interference targeting ß-catenin gene suppresses the growth of xenograft tumorigenesis in nude mouse and the invasiveness and metastatic capability of esophageal carcinoma cells.

Knockdown of fascin1 expression suppresses the proliferation and metastasis of gastric cancer cells.

AIMS: Our current investigation attempts to study the role of the fascin1 gene in growth and metastasis of gastric cancer cell line MKN45. METHODS: Small interfering RNA (siRNA) was used to inhibit fascin1 expression in the human gastric cancer cell line MKN45. Expression of fascin1 in fascin1 siRNA transfected cells (sifascin1), non-transfected cells (NT) and non-specific fascin1 siRNA cells (CON) were examined by Western blotting and reverse transcription polymerase chain reaction (RT-PCR). Cell growth ability in vitro was evaluated by MTT and clone formation assays. Cell mobility in vitro was examined by the Boyden chamber assay. Nude mice metastasis models were established by abdominal cavity transfer method. Tumour growth was evaluated by immunohistochemistry with proliferating cell nuclear antigen (PCNA). RESULTS: Knockdown of fascin1 expression in MKN45 cells resulted in decreased cellular proliferative and migratory abilities. In vitro, the cloning efficiency of siFascin1 cells (34.2%) was significantly lower compared to that in NT (78.5%) (p < 0.05). The migration rate in siFascin1 cells was significantly decreased (33.7%) compared with NT cells (89.4%) (p < 0.05). In vivo, the cell proliferation rate was lower in siFascin1 cells (25.8%) compared to that in NT (75.0%) (p < 0.05). The number of tumour clones in the liver was significantly lower in siFascin1 cells (2.0 +/- 1.1) compared to that in NT (5.1 +/- 1.6) (p < 0.05). CONCLUSIONS: Our study demonstrates that down-regulation of fascin1 suppresses the proliferation and migration of gastric cancer cells MKN45, suggesting that fascin1 siRNA may offer a novel potential gene therapy approach for human gastric cancer with fascin1 over-expression.

Expression of semaphorin 5A and its receptor plexin B3 contributes to invasion and metastasis of gastric carcinoma.

AIM: To investigate the protein and mRNA expression of semaphorin 5A and its receptor plexin B3 in gastric carcinoma and explore its role in the invasion and metastasis of gastric carcinoma. METHODS: Expression of semaphorin 5A and its receptor plexin B3 in 48 samples of primary gastric carcinoma, its corresponding non-neoplastic mucosa, and matched regional lymph node metastasis was assayed by reverse transcription-polymerase chain reaction (RT-PCR), real-time RT-PCR and Western blotting. RESULTS: The protein and mRNA expression of semaphorin 5A and its receptor plexin B3 increased gradually in non-neoplastic mucosa, primary gastric carcinoma and lymph node metastasis (P < 0.05). Moreover, the expression of semaphorin 5A was closely correlated with that of plexin B3. CONCLUSION: Semaphorin 5A and its receptor plexin B3 play an important role in the invasion and metastasis of gastric carcinoma.

Gene silencing of beta-catenin by RNAi inhibits cell proliferation in human esophageal cancer cells in vitro and in nude mice.

beta-Catenin, which is frequently overexpressed in a variety of human cancers including esophageal cancer, mediates cancer cell proliferation and tumor growth. In the present study, we used a human U6 promoter-driven DNA-template approach to induce short hairpin RNA (shRNA)-triggered RNA interference to silence beta-catenin gene expression in human esophageal squamous cell carcinoma cell line Eca-109, and then evaluated its effects on the proliferation and growth of tumor cells in vitro and in nude mice. beta-Catenin expression levels decreased markedly in Eca-109 cells transfected with a plasmid expressing shRNA for beta-catenin. Downregulation of beta-catenin was concomitantly accompanied by reduction of cyclin D1, colony formation, and growth inhibition of Eca-109 cells in vitro. The mechanism appears to be the G0/G1 phase arrest but not induction of apoptosis. In vivo, treatment of Eca-109 cells with beta-catenin shRNA greatly impeded tumor growth in nude mice. We conclude that plasmid vector-mediated beta-catenin RNA interference holds great promise as a novel treatment on human esophageal cancer with beta-catenin overexpression.

Lithium inhibits proliferation of human esophageal cancer cell line Eca-109 by inducing a G2/M cell cycle arrest.

AIM: To investigate the effect of lithium on proliferation of esophageal cancer (EC) cells and its preliminary mechanisms. METHODS: Eca-109 cells were treated with lithium chloride, a highly selective inhibitor of glycogen synthase kinase 3beta (GSK-3beta), at different concentrations (2-30 mmol/L) and time points (0, 2, 4, 6 and 24 h). Cell proliferative ability was evaluated by 3-(4,5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay, and cell cycle distribution was examined by flow cytometry. Expressions of p-GSK-3beta, beta-catenin, cyclin B1, cdc2 and cyclin D1 protein were detected by Western blotting, and the subcellular localization of beta-catenin was determined by immunofluorescence. The mRNA level of cyclin B1 was detected by reverse transcription polymerase chain reaction (RT-PCR). RESULTS: Lithium could inhibit the proliferation of Eca-109 cells. Lithium at a concentration of 20 mmol/L lithium for 24 h produced obvious changes in the distribution of cell cycle, and increased the number of cells in G(2)/M phase (P<0.05 vs control group). Western blotting showed that lithium inhibited GSK-3beta by Ser-9 phosphorylation and stabilized free beta-catenin in the cytoplasm. Immunofluorescence further confirmed that free beta-catenin actively translocated to the nucleus. Moreover, lithium slightly elevated cyclin D1 protein expression, whereas lowered the cyclin B1 expression after 24 h lithium exposure and no obvious change was observed for cdc2 protein. CONCLUSION: Lithium can inhibit the proliferation of human esophageal cancer cell line Eca-109 by inducing a G(2)/M cell cycle arrest, which is mainly mediated through the inhibition of lithium-sensitive molecule, GSK-3beta, and reduction of cyclin B1 expression.