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SLC39A6: a potential target for diagnosis and therapy of esophageal carcinoma.

Cui XB, Shen YY, Jin TT, Li S, Li TT, Zhang SM, Peng H, Liu CX, Li SG, Yang L, Li N, Hu JM, Jiang JF, Li M, Liang WH, Li Y, Wei YT, Sun ZZ, Wu CY, Chen YZ, Li F - J Transl Med (2015)

Bottom Line: And the effects of SLC39A6 silencing by siRNA on cell proliferation, apoptosis, and invasiveness, as well as the proteins involved in epithelial-to-mesenchymal transition (EMT) of esophageal cancer cells, were studied.Increased expression of SLC39A6 was found to be closely correlated with histological grade and early Tumor-Node-Metastasis stage I/II.High tumorous SLC39A6 expression was significantly correlated with shorter overall survival (OS).

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology and Key Laboratory for Xinjiang Endemic and Ethnic Diseases, Shihezi University School of Medicine, North 4th Road, 832002, Shihezi, China. cuixiaobin4363@foxmail.com.

ABSTRACT

Background: Esophageal squamous cell carcinoma (ESCC) is a highly lethal cancer, and its underlying molecular mechanisms are poorly understood. Recent large-scale genome-wide association studies in Chinese Han populations have identified an ESCC susceptibility locus within the SLC39A6 gene. Here, we sought to explore the expression and biological function of SLC39A6 in ESCC.

Methods: Multiethnic validation of SLC39A6 protein expression was performed in different cohorts of patients from Chinese Han and Kazakh populations in the Xinjiang region by immunohistochemistry. The associations among SLC39A6 expression, clinicopathological parameters, and prognosis outcomes of ESCC were analyzed. And the effects of SLC39A6 silencing by siRNA on cell proliferation, apoptosis, and invasiveness, as well as the proteins involved in epithelial-to-mesenchymal transition (EMT) of esophageal cancer cells, were studied.

Results: SLC39A6 protein expression increased progressively from normal esophageal epithelium (NEE) to low-grade intraepithelial neoplasia to ESCC, and finally reached the highest in high-grade intraepithelial neoplasia from Han ethnic. Similarly, SLC39A6 protein was significantly overexpressed in Kazakh ethnic ESCC compared with that in NEE. Increased expression of SLC39A6 was found to be closely correlated with histological grade and early Tumor-Node-Metastasis stage I/II. High tumorous SLC39A6 expression was significantly correlated with shorter overall survival (OS). Cox regression analysis confirmed that SLC39A6 expression was an independent prognostic factor for poor OS in ESCC. Experimentally, the suppression of SLC39A6 expression promoted ESCC cell apoptosis but abrogated proliferation and invasion, and induced an EMT phenotype that included enhanced expression of E-cadherin, loss of vimentin, and morphological changes in ESCC cells in vitro.

Conclusions: Combined, our findings highlight a tumor-promoting role for SLC39A6 in ESCC, suggesting that SLC39A6 could serve as an early detector of high-risk subjects and prognostic biomarker. The targeting of SLC39A6 might be a potential therapeutic strategy for blocking ESCC.

No MeSH data available.


Related in: MedlinePlus

Knockdown of SLC39A6 inhibits cell growth and enhances cell apoptosis in vitro. a, b Eca-109 and EC9706 cells were transfected with either SLC39A6-siRNA or control siRNA after 72 h, the cells were collected, and total cellular protein was used for western blotting analysis with anti-SLC39A6 antibody as described. β-actin served as an internal control. c, d Silencing endogenous SLC39A6 inhibits cell growth as determined by MTT assays. e Silencing endogenous SLC39A6 inhibits cell growth as determined by colony formation assays. f The histograms indicate that the number of colonies formed by cells treated with SLC39A6 siRNA was far fewer than that of control siRNA-treated cells (*p < 0.05; **p < 0.01). g, h Cell apoptosis was detected by Annexin-V/propidium iodide combined labeling flow cytometry in Eca-109 and EC9706 cells upon inhibition of SLC39A6 protein. Flow cytometry analysis shows a large increase in the percentage of cells programmed for apoptosis in Eca-109-siRNA and EC9706-siRNA cells comparing to the corresponding negative controls. i Statistics of the results in (g) and (h). *p < 0.05, versus scramble control (Student’s t test). Error bars represent mean ± SD from three independent experiments
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Fig5: Knockdown of SLC39A6 inhibits cell growth and enhances cell apoptosis in vitro. a, b Eca-109 and EC9706 cells were transfected with either SLC39A6-siRNA or control siRNA after 72 h, the cells were collected, and total cellular protein was used for western blotting analysis with anti-SLC39A6 antibody as described. β-actin served as an internal control. c, d Silencing endogenous SLC39A6 inhibits cell growth as determined by MTT assays. e Silencing endogenous SLC39A6 inhibits cell growth as determined by colony formation assays. f The histograms indicate that the number of colonies formed by cells treated with SLC39A6 siRNA was far fewer than that of control siRNA-treated cells (*p < 0.05; **p < 0.01). g, h Cell apoptosis was detected by Annexin-V/propidium iodide combined labeling flow cytometry in Eca-109 and EC9706 cells upon inhibition of SLC39A6 protein. Flow cytometry analysis shows a large increase in the percentage of cells programmed for apoptosis in Eca-109-siRNA and EC9706-siRNA cells comparing to the corresponding negative controls. i Statistics of the results in (g) and (h). *p < 0.05, versus scramble control (Student’s t test). Error bars represent mean ± SD from three independent experiments

Mentions: To ascertain that SLC39A6 is essential for esophageal cancer cell proliferation, we used siRNAs to deplete SLC39A6 protein in ESCC cells. Western blot analysis demonstrated an efficient knockdown of over 60 % of SLC39A6 protein expression after 72 h of transfection of siRNA against SLC39A6 in a dose-dependent manner but not by control siRNA in Eca109 and EC9706 cell lines (Fig. 5a, b). Cell growth was analyzed using MTT assay to determine whether downregulation of SLC39A6 has an inhibitory effect on ESCC cell proliferation. Growth curves demonstrated that growth of SLC39A6 siRNA-mediated cells was significantly inhibited compared with that of the control group (Fig. 5c, d). For the colony formation assay, the colonies from SLC39A6 siRNA-mediated cells were much smaller than those from the control cells (Fig. 5e), and the number of colonies decreased by an average of four- to eightfold in ECA109 and EC9706 cells compared with that in the control cells (P < 0.05, n = 3, Fig. 5f).Fig. 5


SLC39A6: a potential target for diagnosis and therapy of esophageal carcinoma.

Cui XB, Shen YY, Jin TT, Li S, Li TT, Zhang SM, Peng H, Liu CX, Li SG, Yang L, Li N, Hu JM, Jiang JF, Li M, Liang WH, Li Y, Wei YT, Sun ZZ, Wu CY, Chen YZ, Li F - J Transl Med (2015)

Knockdown of SLC39A6 inhibits cell growth and enhances cell apoptosis in vitro. a, b Eca-109 and EC9706 cells were transfected with either SLC39A6-siRNA or control siRNA after 72 h, the cells were collected, and total cellular protein was used for western blotting analysis with anti-SLC39A6 antibody as described. β-actin served as an internal control. c, d Silencing endogenous SLC39A6 inhibits cell growth as determined by MTT assays. e Silencing endogenous SLC39A6 inhibits cell growth as determined by colony formation assays. f The histograms indicate that the number of colonies formed by cells treated with SLC39A6 siRNA was far fewer than that of control siRNA-treated cells (*p < 0.05; **p < 0.01). g, h Cell apoptosis was detected by Annexin-V/propidium iodide combined labeling flow cytometry in Eca-109 and EC9706 cells upon inhibition of SLC39A6 protein. Flow cytometry analysis shows a large increase in the percentage of cells programmed for apoptosis in Eca-109-siRNA and EC9706-siRNA cells comparing to the corresponding negative controls. i Statistics of the results in (g) and (h). *p < 0.05, versus scramble control (Student’s t test). Error bars represent mean ± SD from three independent experiments
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Fig5: Knockdown of SLC39A6 inhibits cell growth and enhances cell apoptosis in vitro. a, b Eca-109 and EC9706 cells were transfected with either SLC39A6-siRNA or control siRNA after 72 h, the cells were collected, and total cellular protein was used for western blotting analysis with anti-SLC39A6 antibody as described. β-actin served as an internal control. c, d Silencing endogenous SLC39A6 inhibits cell growth as determined by MTT assays. e Silencing endogenous SLC39A6 inhibits cell growth as determined by colony formation assays. f The histograms indicate that the number of colonies formed by cells treated with SLC39A6 siRNA was far fewer than that of control siRNA-treated cells (*p < 0.05; **p < 0.01). g, h Cell apoptosis was detected by Annexin-V/propidium iodide combined labeling flow cytometry in Eca-109 and EC9706 cells upon inhibition of SLC39A6 protein. Flow cytometry analysis shows a large increase in the percentage of cells programmed for apoptosis in Eca-109-siRNA and EC9706-siRNA cells comparing to the corresponding negative controls. i Statistics of the results in (g) and (h). *p < 0.05, versus scramble control (Student’s t test). Error bars represent mean ± SD from three independent experiments
Mentions: To ascertain that SLC39A6 is essential for esophageal cancer cell proliferation, we used siRNAs to deplete SLC39A6 protein in ESCC cells. Western blot analysis demonstrated an efficient knockdown of over 60 % of SLC39A6 protein expression after 72 h of transfection of siRNA against SLC39A6 in a dose-dependent manner but not by control siRNA in Eca109 and EC9706 cell lines (Fig. 5a, b). Cell growth was analyzed using MTT assay to determine whether downregulation of SLC39A6 has an inhibitory effect on ESCC cell proliferation. Growth curves demonstrated that growth of SLC39A6 siRNA-mediated cells was significantly inhibited compared with that of the control group (Fig. 5c, d). For the colony formation assay, the colonies from SLC39A6 siRNA-mediated cells were much smaller than those from the control cells (Fig. 5e), and the number of colonies decreased by an average of four- to eightfold in ECA109 and EC9706 cells compared with that in the control cells (P < 0.05, n = 3, Fig. 5f).Fig. 5

Bottom Line: And the effects of SLC39A6 silencing by siRNA on cell proliferation, apoptosis, and invasiveness, as well as the proteins involved in epithelial-to-mesenchymal transition (EMT) of esophageal cancer cells, were studied.Increased expression of SLC39A6 was found to be closely correlated with histological grade and early Tumor-Node-Metastasis stage I/II.High tumorous SLC39A6 expression was significantly correlated with shorter overall survival (OS).

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology and Key Laboratory for Xinjiang Endemic and Ethnic Diseases, Shihezi University School of Medicine, North 4th Road, 832002, Shihezi, China. cuixiaobin4363@foxmail.com.

ABSTRACT

Background: Esophageal squamous cell carcinoma (ESCC) is a highly lethal cancer, and its underlying molecular mechanisms are poorly understood. Recent large-scale genome-wide association studies in Chinese Han populations have identified an ESCC susceptibility locus within the SLC39A6 gene. Here, we sought to explore the expression and biological function of SLC39A6 in ESCC.

Methods: Multiethnic validation of SLC39A6 protein expression was performed in different cohorts of patients from Chinese Han and Kazakh populations in the Xinjiang region by immunohistochemistry. The associations among SLC39A6 expression, clinicopathological parameters, and prognosis outcomes of ESCC were analyzed. And the effects of SLC39A6 silencing by siRNA on cell proliferation, apoptosis, and invasiveness, as well as the proteins involved in epithelial-to-mesenchymal transition (EMT) of esophageal cancer cells, were studied.

Results: SLC39A6 protein expression increased progressively from normal esophageal epithelium (NEE) to low-grade intraepithelial neoplasia to ESCC, and finally reached the highest in high-grade intraepithelial neoplasia from Han ethnic. Similarly, SLC39A6 protein was significantly overexpressed in Kazakh ethnic ESCC compared with that in NEE. Increased expression of SLC39A6 was found to be closely correlated with histological grade and early Tumor-Node-Metastasis stage I/II. High tumorous SLC39A6 expression was significantly correlated with shorter overall survival (OS). Cox regression analysis confirmed that SLC39A6 expression was an independent prognostic factor for poor OS in ESCC. Experimentally, the suppression of SLC39A6 expression promoted ESCC cell apoptosis but abrogated proliferation and invasion, and induced an EMT phenotype that included enhanced expression of E-cadherin, loss of vimentin, and morphological changes in ESCC cells in vitro.

Conclusions: Combined, our findings highlight a tumor-promoting role for SLC39A6 in ESCC, suggesting that SLC39A6 could serve as an early detector of high-risk subjects and prognostic biomarker. The targeting of SLC39A6 might be a potential therapeutic strategy for blocking ESCC.

No MeSH data available.


Related in: MedlinePlus