| 1. |
- Chien, Ming-Hsien, et al.
(author)
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Vascular endothelial growth factor-C (VEGF-C) promotes angiogenesis by induction of COX-2 in leukemic cells via the VEGF-R3/JNK/AP-1 pathway.
- 2009
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In: Carcinogenesis. - : Oxford University Press (OUP). - 0143-3334 .- 1460-2180. ; 30:12, s. 2005-13
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Journal article (peer-reviewed)abstract
- Vascular endothelial growth factor (VEGF)-C is recognized as a tumor lymphangiogenic factor based on the effects of activated VEGF-R3 on lymphatic endothelial cells. Many tumor cells express VEGF-R3 but the function of this receptor in tumor cells is largely unknown. It has been reported that the VEGF-C/VEGF-R3 axis is activated in subsets of leukemia patients. Herein, we have shown that VEGF-C induces angiogenic activity in the tube formation assay invitro and Matrigel plug assay in vivo by upregulating an angiogenic factor, cyclooxygenase-2 (COX-2), through VEGF-R3 in the human acute myeloid leukemia (AML) cell line, THP-1. COX-2 induction by VEGF-C was also observed in other VEGF-R3(+) human AML cell lines (U937 and HL60). Moreover, immunohistochemical analysis of bone marrow specimens of 37 patients diagnosed with AML revealed that VEGF-C expression in specimens was associated with the expression of COX-2 (P < 0.001). The manner by which signaling pathways transduced by VEGF-C is responsible for COX-2 upregulation was further investigated. Blocking the p42/44 mitogen-activated protein kinase (MAPK) pathway with the MAPK kinase inhibitor, PD 98059, failed to inhibit VEGF-C-mediated COX-2 expression. However, VEGF-C-induced COX-2 upregulation was effectively abolished by overexpression of dominant-negative c-Jun N-terminal kinase (JNK) or treatment with the JNK inhibitor, SP 600125. VEGF-C induced JNK-dependent nuclear translocation of c-Jun. Furthermore, chromatin immunoprecipitation and reporter assays revealed that VEGF-C enhanced c-Jun binding to the cyclic adenosine 3',5'-monophosphate-response element of the COX-2 promoter and induced COX-2 expression. In sum, the data herein highlight the pathogenic role of VEGF-C in leukemia via regulation of angiogenesis through upregulation of COX-2.
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| 2. |
- Zhang, Jin-Ting, et al.
(author)
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Nuclear to cytoplasmic shift of p33ING1b protein from normal oral mucosa to oral squamous cell carcinoma in relation to clinicopathological variables
- 2008
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In: Journal of Cancer Research and Clinical Oncology. - : Springer Science and Business Media LLC. - 0171-5216 .- 1432-1335. ; 134:3, s. 421-426
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Journal article (peer-reviewed)abstract
- Purpose: p33ING1b, as a candidate tumour suppressor gene, has been found to be expressed a proportion of oral squamous cell carcinomas (OSCCs), however, its clinicopathological significance is not studied yet. Our aim was to investigate association of p33ING1b expression with clinicopathological variables and particularly interesting new cysteine-histidine rich protein (PINCH) in OSCCs. Methods: p33ING1b expression was immumohistochemically examined in 20 normal oral mucosa specimens and 49 OSCCs. Results: Normal squamous cells showed only p33ING1b nuclear expression (no cytoplasmic expression), with a rate of 90% positive cases. While 24% of OSCCs appeared cytoplasmic expression (11 of them with weak nuclear staining) and the rest tumours (76%) were negative for p33 ING1b. Furthermore, the cases having lymph node metastasis showed a higher frequency of positive cytoplasmic expression than those without metastasis (P = 0.03). The p33ING1b cytoplasmic expression was positively related to PINCH expression (P = 0.04), the cases positive for both proteins had a high rate of the metastasis (P = 0.03). Conclusions: The transfer of p33ING1b protein from the nucleus to the cytoplasm may result in loss of normal cellular function of the protein, which might play a role in the tumourigenesis and metastasis of OSCCs. © 2007 Springer-Verlag.
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| 3. |
- Adnane, Bouchaib, et al.
(author)
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Origin of photoresponse at 8-14 μm in stacks of self-assembled SiGe/Si quantum dots
- 2009
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In: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X.
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Journal article (other academic/artistic)abstract
- A normal incidence photodetector operating at 8-14 μm is demonstrated using p-type δ-doped SiGe dot multilayer structures grown by molecular beam epitaxy on Si(001) substrates. Based on the experimental results of photoluminescence and photoluminescence excitation spectroscopies together with numerical analysis, the origin of the measured photocurrent was attributed to intersubband optical transitions between the heavy hole and light hole states of the valence band of the self-assembled SiGe dots and subsequent lateral transport of photo-excited carriers in the conduction channels formed by Ge wetting layers.
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| 4. |
- Duan, Ming-Rui, et al.
(author)
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DNA binding mechanism revealed by high resolution crystal structure of Arabidopsis thaliana WRKY1 protein
- 2007
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In: Nucleic Acids Research. - : Oxford University Press (OUP). - 1362-4962 .- 0305-1048. ; 35:4, s. 54-1145
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Journal article (peer-reviewed)abstract
- WRKY proteins, defined by the conserved WRKYGQK sequence, are comprised of a large superfamily of transcription factors identified specifically from the plant kingdom. This superfamily plays important roles in plant disease resistance, abiotic stress, senescence as well as in some developmental processes. In this study, the Arabidopsis WRKY1 was shown to be involved in the salicylic acid signaling pathway and partially dependent on NPR1; a C-terminal domain of WRKY1, AtWRKY1-C, was constructed for structural studies. Previous investigations showed that DNA binding of the WRKY proteins was localized at the WRKY domains and these domains may define novel zinc-binding motifs. The crystal structure of the AtWRKY1-C determined at 1.6 A resolution has revealed that this domain is composed of a globular structure with five beta strands, forming an antiparallel beta-sheet. A novel zinc-binding site is situated at one end of the beta-sheet, between strands beta4 and beta5. Based on this high-resolution crystal structure and site-directed mutagenesis, we have defined and confirmed that the DNA-binding residues of AtWRKY1-C are located at beta2 and beta3 strands. These results provided us with structural information to understand the mechanism of transcriptional control and signal transduction events of the WRKY proteins.
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| 5. |
- Elfving, Anders, et al.
(author)
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Asymmetric relaxation of SiGe/Si(110) investigated by high-resolution x-ray diffraction reciprocal space mapping
- 2006
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In: Applied physics letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 89, s. 181901-1--181901-3
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Journal article (peer-reviewed)abstract
- Strain relaxation of SiGe/Si(110) has been studied by x-ray reciprocal space mapping. To get information about the in-plane lattice mismatch in different directions, two-dimensional maps around, e.g., (260) and (062) reciprocal lattice points have been obtained from Si0.8Ge0.2/Si(110) samples, which were exposed to different annealing conditions. The in-plane lattice mismatch was found to be asymmetric with the major strain relaxation observed in the lateral [001] direction. This was associated with the formation and propagation of dislocations oriented along [10]. The relaxation of as-grown structures during postannealing is thus different from relaxation during growth, which is mainly along [10].
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| 6. |
- Gao, Yan, et al.
(author)
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Synthesis and photophysical and electrochemical properties of a binuclear Ru(bpy)(3)-Cu(III) corrole complex
- 2007
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In: Journal of Porphyrins and Phthalocyanines. - 1088-4246 .- 1099-1409. ; 11:06-maj, s. 463-469
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Journal article (peer-reviewed)abstract
- A novel binuclear Ru-Cu complex, composed of a copper(III)-corrole and a ruthenium(II) tris(bipyridine) moicty linked by an amide bond, has been synthesized and characterized by H-1 NMR, UV-vis and mass spectrometry. The steady-state emission and the electrochemical properties were investigated. Compared to the parent [Ru(bpy)(3)](2+), the emission-of the desired complex was substantially quenched when the MLCT of [Ru(bpy)(3)](2+) was selectively photoexcited.
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| 7. |
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| 8. |
- Huang, Daming, et al.
(author)
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A Modified Charge-Pumping Method for the Characterization of Interface-Trap Generation in MOSFETs
- 2009
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In: IEEE Transactions on Electron Devices. - 0018-9383 .- 1557-9646. ; 56:2, s. 267-274
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Journal article (peer-reviewed)abstract
- A novel recovery-free interface-trap measurement method is presented in detail. This method is the modification of the conventional charge pumping (CP) by extending the pulse low level to the stress-bias and minimizing the pulse high-level duty cycle to suppress the recovery effect. The method is applied to study the negative-bias temperature instability in p-MOSFETs. As compared with the conventional CP, a much larger interface-trap generation under stress is observed by the new method. A power law time dependence (similar to t(n)) of interface-trap generation is observed. The index n. is less than that derived from conventional CP and increases with temperature, demonstrating a dispersive process involved in the trap generation dynamics.
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| 9. |
- Klionsky, Daniel J., et al.
(author)
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Guidelines for the use and interpretation of assays for monitoring autophagy in higher eukaryotes
- 2008
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In: Autophagy. - : Landes Bioscience. - 1554-8627 .- 1554-8635. ; 4:2, s. 151-175
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Research review (peer-reviewed)abstract
- Research in autophagy continues to accelerate,1 and as a result many new scientists are entering the field. Accordingly, it is important to establish a standard set of criteria for monitoring macroautophagy in different organisms. Recent reviews have described the range of assays that have been used for this purpose.2,3 There are many useful and convenient methods that can be used to monitor macroautophagy in yeast, but relatively few in other model systems, and there is much confusion regarding acceptable methods to measure macroautophagy in higher eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers of autophagosomes versus those that measure flux through the autophagy pathway; thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from fully functional autophagy that includes delivery to, and degradation within, lysosomes (in most higher eukaryotes) or the vacuole (in plants and fungi). Here, we present a set of guidelines for the selection and interpretation of the methods that can be used by investigators who are attempting to examine macroautophagy and related processes, as well as by reviewers who need to provide realistic and reasonable critiques of papers that investigate these processes. This set of guidelines is not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to verify an autophagic response.
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| 10. |
- Larsson, David A, et al.
(author)
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Oxysterol mixtures, in atheroma-relevant proportions, display synergistic and proapoptotic effects
- 2006
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In: Free Radical Biology & Medicine. - : Elsevier BV. - 0891-5849 .- 1873-4596. ; 41:6, s. 902-910
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Journal article (peer-reviewed)abstract
- Apoptotic cells in atheroma lesions may contribute to plaque development and instability. Oxysterols constitute the major toxic component in oxLDL and are present in mixed forms in human atheroma lesions. However, the cellular effects of oxysterols have been mostly studied individually. In the present study, we investigated the cytotoxic effects of 7β-hydroxycholesterol (7βOH), 7-ketocholesterol (7keto), 25-hydroxycholesterol (25OH), and 27-hydroxycholesterol (27OH) on U937 monocytic cells, both individually and in atheroma-relevant mixtures mimicking the oxysterol composition reported in human atheroma lesions. Apoptosis and necrosis were studied by examining cell morphology, phosphatidylserine exposure, caspase activation, and the terminal dUTP nick end-labeling technique. Cellular reactive oxygen species and total amount of reduced thiols were measured by using fluorescence probes and 5,5′-dithiobis-(2-nitrobenzoic acid), respectively. We found that 7βOH and 7keto induced caspase activation, ROS production, cellular thiol depletion, permeabilization of lysosomal and mitochondrial membranes, and cell death. 25OH and 27OH did not cause any of the above alterations, whereas 7βOH and 7keto exerted synergistic toxic effects. Although single 25OH or 27OH exhibited quenching effects on both 7βOH- and 7keto-induced cell death, the combination of all four oxysterols in atheroma-relevant proportions was proapoptotic. Our findings indicate that the major oxysterols accumulated in human atheroma are proapoptotic and may contribute to atherosclerotic lesion development. © 2006 Elsevier Inc. All rights reserved.
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