Browsing by Author "Lin, Po-Cheng"

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Butylidenephthalide Suppresses Human Telomerase Reverse Transcriptase (TERT) in Human Glioblastomas
(2011-11-01)
Lin, Po-Cheng
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Lin, Shinn-Zong
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Chen, Yi-Lin
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Chang, Jeng-Shou
;
Ho, Li-Ing
Telomerase is widely expressed in most human cancers, but is almost undetectable in normal somatic cells and is therefore a potential drug target. Using the human telomerase promoter platform, the naturally occurring compound butylidenephthalide (BP) was selected for subsequent investigation of antitumor activity in vitro and in vivo. We treated human glioblastoma cells with BP and found a dose-dependent decrease in human telomerase reverse transcriptase (hTERT) mRNA expression and a concomitant increase in p16 and p21 expression. Because c-Myc and Sp1 are involved in transcriptional regulation of hTERT, the effect of BP on c-Myc and Sp1 expression was examined. Using electrophoretic mobility shift assays and western blotting, we showed that BP represses hTERT transcriptional activity via downregulation of Sp1 expression. Using the telomerase repeat amplification protocol, an association between BP concentration and suppression of telomerase activity, induction of human glioblastoma senescence, and inhibition of cellular proliferation was identified. This was supported by a mouse xenograft model, in which BP repressed telomerase and inhibited tumor proliferation, resulting in tumor senescence. Overexpression of hTERT restored telomerase activity in human glioblastoma cells and overcame replicative senescence. These findings suggest that BP inhibits proliferation and induces senescence in human glioblastomas by downregulating hTERT expression and consequently telomerase activity. This is the first study to describe regulation of telomerase activity by BP in human glioblastomas.
DEVELOPMENT OF OPTIMAL VARIABLE SPEED-LIMIT CONTROL MODEL
(2009)
Chiou, Yu-Chiun
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Lan, Lawrence W.
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Lin, Po-Cheng
;
Huang, Yen-Fei
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運輸與物流管理系註：原交通所+運管所
Application of variable speed-limit (VSL) control has become promising in managing the incidents in the contexts of intelligent highway systems wherein advanced VSL signs are densely placed along the roadways. This paper aims to develop a genetic-fuzzy-logic-controller (GFLC)-based VSL control model with an objective function to enhance both safety and throughput efficiency at the incident sites. In order to evaluate the performance of learned logic rules and tuned membership function, a revised cell transmission model (CTM) is proposed, which is validated with field traffic data. The results indicate that the proposed VSL control model can effectively curtail the crash likelihood without deteriorating or only slightly decreasing the throughput efficiency under different tested incident cases. It suggests that our proposed GFLC-based VSL control model is promising for practical applications.
Optimal variable speed-limit control under abnormal traffic conditions
(2012-04-01)
Chiou, Yu-Chiun
;
Huang, Yen-Fei
;
Lin, Po-Cheng
;
運輸與物流管理系註：原交通所+運管所
;
Department of Transportation and Logistics Management
Application of variable speed-limit (VSL) control has become promising in managing incidents in the context of intelligent highway systems, wherein advanced VSL signs are densely placed along the roadways. This paper aims to develop a genetic-fuzzy-logic-controller (GFLC)-based VSL control model with an objective function to enhance both safety and throughput efficiency at incident sites. In order to evaluate the performance of learned logic rules and tuned membership function, a revised cell transmission model is proposed, which is validated with field traffic data. The results indicate that the proposed VSL control model can effectively curtail crash likelihood while only slightly decreasing the throughput efficiency under different tested incident cases. It suggests that our proposed GFLC-based VSL control model is promising for practical applications.
Pulsed Electromagnetic Fields Accelerate Proliferation and Osteogenic Gene Expression in Human Bone Marrow Mesenchymal Stem Cells During Osteogenic Differentiation
(2010-04-01)
Sun, Li-Yi
;
Hsieh, Dean-Kuo
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Lin, Po-Cheng
;
Chiu, Hsien-Tai
;
Chiou, Tzyy-Wen
Osteogenesis is a complex series of events involving the differentiation of mesenchymal stem cells to generate new bone. In this study, we examined the effect of pulsed electromagnetic fields (PEMFs) on cell proliferation, alkaline phosphatase (ALP) activity, mineralization of the extracellular matrix, and gene expression in bone marrow mesenchymal stem cells (BMMSCs) during osteogenic differentiation. Exposure of BMMISCs to PEMFs increased cell proliferation by 29.6% compared to untreated cells at day 1 of differentiation. Semi-quantitative RT-PCR indicated that PEMFs significantly altered temporal expression of osteogenesis-related genes, including a 2.7-fold increase in expression of the key osteogenesis regulatory gene cbfa1, compared to untreated controls. In addition, exposure to PEMFs significantly increased ALP expression during the early stages of osteogenesis and substantially enhanced mineralization near the midpoint of osteogenesis. These results suggest that PEMFs enhance early cell proliferation in B M MSC-mediated osteogenesis, and accelerate the osteogenesis. Bioelectromatmetics 31:209-219, 2010. (C) 2009 Wiley-Liss, Inc.