Browsing by Author "Sun, SJ"

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Induction of apoptosis in MCF-7 human breast cancer cells by phytochemicals from Anoectochilus formosanus
(2004-01-01)
Shyur, LF
;
Chen, CH
;
Lo, CP
;
Wang, SY
;
Kang, PL
The antitumor activity of Anoectochilus formosanus Hayata (Orchidaceae), a popularly used folk medicine in the treatment of cancers in Asia, was investigated in MCF-7 human mammary carcinoma cells. Plant extracts of A. formosanus were observed to induce apoptosis of MCF-7 cells as evidenced by cell-morphological changes, an early redistribution of plasma membrane phosphatidylserine, and DNA content distribution studies. Bioactivity-guided fractionation of A. formosanus extracts produced a specific ethyl acetate (EA)-partitioned fraction in which apoptotic activity was enriched. The chemical profile and candidate index compounds of the active EA fraction were obtained using HPLC and various spectral analyses. Western blot analysis showed that upon treatment of MCF-7 cells with the EA fraction, cleavage of pro-caspases-8, -9, and -7, and poly(ADP-ribose) polymerase as well as significant release of mitochondrial cytochrome c into the cytosol were readily observed. Flow cytometry showed that the Fas ligand protein was overexpressed in EA-treated MCF-7 cells. Functional genomic studies indicated that specific genes related to cytoskeleton rearrangement, apoptotic signal transduction, and various transcription factors were differentially regulated in EA-treated MCF-7 cells. Putative apoptotic signaling pathways of MCF-7 cells in response to the EA extract of A. formosanus are proposed. Copyright (C) 2004 National Science Council, ROC and S. Karger AG, Basel.
Strong anisotrpoic maganetoresistance and magnetic interaction in La0.7Ce0.3Mn0.3/La0.7Ca0.3MnO3 p-n junction
(2005-05-15)
Chou, H
;
Hong, ZY
;
Sun, SJ
;
Juang, JY
;
Chang, WJ
The p-n junction made by colossal magnetoresistance materials, such as La0.7Ce0.3MnO3/La0.7Ca0.3MnO3, has great interest for its potential applications. However, the physics of the magnetic state and transport properties of the interface still remains open. In this article, bilayer La0.7Ce0.3MnO3/La0.7Ca0.3MnO3/STO films with a nearly perfect interface were studied. The p-n interface possibly becomes an antiferromagnetion-insulating layer as their parent compound, LaMnO3, and confines the bias current flowing only on the top layer. The top and bottom layers interact with each other in a way that a strong anisotropy tin magnetoresistance measurements was observed. (c) 2005 American Institute of Physics.