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- Guan, Pei-Pei, et al.
(författare)
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By activating matrix metalloproteinase-7, shear stress promotes chondrosarcoma cell motility, invasion and lung colonization.
- 2015
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Ingår i: Oncotarget. - : Impact Journals, LLC. - 1949-2553. ; 6:11, s. 9140-9159
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Tidskriftsartikel (refereegranskat)abstract
- Interstitial fluid flow and associated shear stress are relevant mechanical signals in cartilage and bone (patho)physiology. However, their effects on chondrosarcoma cell motility, invasion and metastasis have yet to be delineated. Using human SW1353, HS.819.T and CH2879 chondrosarcoma cell lines as model systems, we found that fluid shear stress induces the accumulation of cyclic AMP (cAMP) and interleukin-1β (IL-1β), which in turn markedly enhance chondrosarcoma cell motility and invasion via the induction of matrix metalloproteinase-7 (MMP-7). Specifically, shear-induced cAMP and IL-1β activate PI3-K, ERK1/2 and p38 signaling pathways, which lead to the synthesis of MMP-7 via transactivating NF-κB and c-Jun in human chondrosarcoma cells. Importantly, MMP-7 upregulation in response to shear stress exposure has the ability to promote lung colonization of chondrosarcomas in vivo. These findings offer a better understanding of the mechanisms underlying MMP-7 activation in shear-stimulated chondrosarcoma cells, and provide insights on designing new therapeutic strategies to interfere with chondrosarcoma invasion and metastasis.
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- Li, Jing, et al.
(författare)
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Shared Molecular Targets Confer Resistance over Short and Long Evolutionary Timescales
- 2019
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Ingår i: Molecular Biology and Evolution. - : Oxford University Press (OUP). - 1537-1719 .- 0737-4038. ; 36:4, s. 691-708
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Tidskriftsartikel (refereegranskat)abstract
- Pre-existing and de novo genetic variants can both drive adaptation to environmental changes, but their relative contributions and interplay remain poorly understood. Here we investigated the evolutionary dynamics in drug-treated yeast populations with different levels of pre-existing variation by experimental evolution coupled with time-resolved sequencing and phenotyping. We found a doubling of pre-existing variation alone boosts the adaptation by 64.1% and 51.5% in hydroxyurea and rapamycin, respectively. The causative pre-existing and de novo variants were selected on shared targets: RNR4 in hydroxyurea and TOR1, TOR2 in rapamycin. Interestingly, the pre-existing and de novo TOR variants map to different functional domains and act via distinct mechanisms. The pre-existing TOR variants from two domesticated strains exhibited opposite rapamycin resistance effects, reflecting lineage-specific functional divergence. This study provides a dynamic view on how pre-existing and de novo variants interactively drive adaptation and deepens our understanding of clonally evolving populations.
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| 4. |
- Liu, Jia, et al.
(författare)
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Highly efficient Ru/MnO2 nano-catalysts for Li-O2 batteries : Quantitative analysis of catalytic Li2O2 decomposition by operando synchrotron X-ray diffraction
- 2017
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Ingår i: Journal of Power Sources. - : Elsevier BV. - 0378-7753 .- 1873-2755. ; 352, s. 208-215
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Tidskriftsartikel (refereegranskat)abstract
- In-situ or operando quantitative analysis is very important for Li-O2 batteries, in order to properly, accurately and comprehensively evaluate electrocatalysts and characterize Li-O2 electrochemistry in real-time. Synchrotron XRD can provide much higher X-ray intensity and time resolution than traditional in-house diffractometers, and therefore can contribute to quantitative analysis for Li-O2 batteries. Here, operando synchrotron XRD is further developed to quantitatively study Li-O2 batteries with nano catalysts, Ru/MnO2. The time-resolved oxygen evolution reaction (OER) kinetics for Li-O2 cells with Ru/MNT was systematically investigated using operando synchrotron radiation powder X-ray diffraction (SR-PXD). Li2O2 decomposition in the electrodes with Ru/MNT catalysts during galvanostatic and potentiostatic charge processes followed pseudo-zero-order kinetics and showed ideal Coulombic efficiency (close to 100%). Furthermore, it was found that the OER kinetics for a cell with 2 wt% Ru/MNT charged at a constant potential of 4.3 V was even faster than that for a cell with the same amount of pure Ru nanoparticles, which have been considered as a highly active catalyst for Li-O2 batteries. These results indicated that Ru/MNT with a special nanostructure represented a very efficient electrocatalyst for promoting the OER in Li-O2 batteries. We also demonstrate that synchrotron radiation XRD can "highlight" a way to quantitative analysis for Li-O2 batteries.
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