Browsing by Author "Cheng, Chun-Wen"

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MicroRNA-30a increases tight junction protein expression to suppress the epithelial-mesenchymal transition and metastasis by targeting Slug in breast cancer
(2016-03-29)
Chang, Chia-Wei
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Yu, Jyh-Cherng
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Hsieh, Yi-Hsien
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Yao, Chung-Chin
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Chao, Jui-I
The epithelial-to-mesenchymal (EMT) transition is a prerequisite for conferring metastatic potential during tumor progression. microRNA-30a (miR-30a) expression was significantly lower in aggressive breast cancer cell lines compared with non-invasive breast cancer and non-malignant mammary epithelial cell lines. In contrast, miR-30a overexpression reversed the mesenchymal appearance of cancer cells to result in a cobblestone-like epithelial phenotype. We identified Slug, one of the master regulators of EMT, as a target of miR-30a using in silico prediction. Reporter assays indicated that miR-30a could bind to the 3'-untranslted region of Slug mRNA. Furthermore, we linked miR-30a to increased expression of claudins, a family of tight junction transmembrane proteins. An interaction between Slug and E-box in the claudin promoter sequences was reduced upon miR-30a overexpression, further leading to reduction of filopodia formation and decreased invasiveness/metastasis capabilities of breast cancer cells. Consistently, delivery of miR-30a in xenografted mice decreased tumor invasion and migration. In patients with breast cancer, a significantly elevated risk of the miR-30a(low)/CLDN2(low)/FSCNhigh genotype was observed, linking to a phenotypic manifestation of larger tumor size, lymph node metastasis, and advanced tumor stage among patients. In conclusion, the miR-30a/Slug axis inhibits mesenchymal tumor development by interfering with metastatic cancer cell programming and may be a potential target for therapy in breast cancer.
MicroRNA-30a inhibits cell migration and invasion by downregulating vimentin expression and is a potential prognostic marker in breast cancer
(2012-08-01)
Cheng, Chun-Wen
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Wang, Hsiao-Wei
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Chang, Chia-Wei
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Chu, Hou-Wei
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Chen, Cheng-You
"Tumor recurrence and metastasis result in an unfavorable prognosis for cancer patients. Recent studies have suggested that specific microRNAs (miRNAs) may play important roles in the development of cancer cells. However, prognostic markers and the outcome prediction of the miRNA signature in breast cancer patients have not been comprehensively assessed. The aim of this study was to identify miRNA biomarkers relating to clinicopathological features and outcome of breast cancer. A miRNA microarray analysis was performed on breast tumors of different lymph node metastasis status and with different progression signatures, indicated by overexpression of cyclin D1 and beta-catenin genes, to identify miRNAs showing a significant difference in expression. The functional interaction between the candidate miRNA, miR-30a, and the target gene, Vim, which codes for vimentin, a protein involved in epithelial-mesenchymal transition, was examined using the luciferase reporter assay, western blotting, and migration and invasion assays. The association between the decreased miR-30a levels and breast cancer progression was examined in a survival analysis. miR-30a negatively regulated vimentin expression by binding to the 3'-untranslated region of Vim. Overexpression of miR-30a suppressed the migration and invasiveness phenotypes of breast cancer cell lines. Moreover, reduced tumor expression of miR-30a in breast cancer patients was associated with an unfavorable outcome, including late tumor stage, lymph node metastasis, and worse progression (mortality and recurrence) (p < 0.05). In conclusion, these findings suggest a role for miR-30a in inhibiting breast tumor invasiveness and metastasis. The finding that miR-30a downmodulates vimentin expression might provide a therapeutic target for the treatment of breast cancer."
The resistive switching characteristics of a Ti/Gd(2)O(3)/Pt RRAM device
(2010-05-01)
Liu, Kou-Chen
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Tzeng, Wen-Hsien
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Chang, Kow-Ming
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Chan, Yi-Chun
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Kuo, Chun-Chih
We successfully fabricated the Gd(2)O(3) film for the application of resistive random access memory (RRAM). The resistive switching behavior of the Ti/Gd(2)O(3)/Pt capacitor structure could be both operated under positive or negative bias. However, there was a significant difference on the switching properties. The switching behavior under positive bias operation was more stable, had less voltage and resistance fluctuation, and had longer endurance than that of the negative one. We propose that the anode electrode plays an important role in the switching characteristics and may be the cause of the asymmetry of the I-V curves between positive and negative operation. (C) 2010 Elsevier Ltd. All rights reserved.
The resistive switching characteristics of a Ti/Gd2O3/Pt RRAM device
(2010-05-01)
Liu, Kou-Chen
;
Tzeng, Wen-Hsien
;
Chang, Kow-Ming
;
Chan, Yi-Chun
;
Kuo, Chun-Chih
We successfully fabricated the Gd2O3 film for the application of resistive random access memory (RRAM). The resistive switching behavior of the Ti/Gd2O3/Pt capacitor structure could be both operated under positive or negative bias. However, there was a significant difference on the switching properties. The switching behavior under positive bias operation was more stable, had less voltage and resistance fluctuation, and had longer endurance than that of the negative one. We propose that the anode electrode plays an important role in the switching characteristics and may be the cause of the asymmetry of the I-V curves between positive and negative operation. (C) 2010 Elsevier Ltd. All rights reserved.
Transparent resistive random access memory (T-RRAM) based on Gd2O3 film and its resistive switching characteristics
(2010)
Liu, Kou-Chen
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Tzeng, Wen-Hsien
;
Chang, Kow-Ming
;
Chan, Yi-Chun
;
Kuo, Chun-Chih
A transparent resistive random access memory (T-RRAM) based on ITO/Gd2O3/ITO capacitor structure is successfully fabricated on Glass substrate by pulse laser deposition (PLD) at room temperature. Under bipolar operation, the ITO/Gd2O3/ITO device exhibits reliable and stable resistive switching behaviors for more than 200 switching cycles and low operation voltage of -2V/+2V. Furthermore, our device demonstrates nonpolar resistive switching characteristic which exhibits high potential to be applied for the next generation nonvolatile memory.