Extracellular matrix, integrins, and growth factors as tailors of the stem cell niche

2012 ◽  
Vol 24 (5) ◽  
pp. 645-651 ◽  
Author(s):  
Maria Felice Brizzi ◽  
Guido Tarone ◽  
Paola Defilippi
2011 ◽  
Vol 71 (11) ◽  
pp. 1006-1017 ◽  
Author(s):  
Ilias Kazanis ◽  
Charles ffrench-Constant

2020 ◽  
Author(s):  
Lucía Benítez ◽  
Lucas Barberis ◽  
Luciano Vellón ◽  
Carlos Alberto Condat

Abstract Background: Cancer stem cells are important for the development of many solid tumors. These cells receive promoting and inhibitory signals that depend on the nature of their environment (their niche) and determine cell dynamics. Mechanical stresses are crucial to the initiation and interpretation of these signals. Methods: A two-population mathematical model of tumorsphere growth is used to interpret the results of a series of experiments recently carried out in Tianjin, China, and extract information about the intraspecific and interspecific interactions between cancer stem cell and differentiated cancer cell populations. Results: The model allows us to reconstruct the time evolution of the cancer stem cell fraction, which was not directly measured. We find that, in the presence of stem cell growth factors, the interspecific cooperation between cancer stem cells and differentiated cancer cells induces a positive feedback loop that determines growth, independently of substrate hardness. In a frustrated attempt to reconstitute the stem cell niche, the number of cancer stem cells increases continuously with a reproduction rate that is enhanced by a hard substrate. For growth on soft agar, intraspecific interactions are always inhibitory, but on hard agar the interactions between stem cells are collaborative while those between differentiated cells are strongly inhibitory. Evidence also suggests that a hard substrate brings about a large fraction of asymmetric stem cell divisions. In the absence of stem cell growth factors, the barrier to differentiation is broken and overall growth is faster, even if the stem cell number is conserved. Conclusions: Our interpretation of the experimental results validates the centrality of the concept of stem cell niche when tumor growth is fueled by cancer stem cells. Niche memory is found to be responsible for the characteristic population dynamics observed in tumorspheres. A specific condition for the growth of the cancer stem cell number is also obtained.


2017 ◽  
Vol 145 ◽  
pp. S173
Author(s):  
Meryem Baghdadi ◽  
David Castel ◽  
So-ichiro Fukada ◽  
David Birk ◽  
Frederic Relaix ◽  
...  

2016 ◽  
Author(s):  
Marcos Assis Nascimento ◽  
Lydia Sorokin ◽  
Tatiana Coelho-Sampaio

AbstractFractones are extracellular matrix structures in the neural stem cell niche of the subventricular zone (SVZ), where they appear as round deposits named bulbs or thin branching lines called stems. Their cellular origin and what determines their localization at this site is poorly studied and it remains unclear whether they influence neural stem and progenitor cells formation, proliferation and/or maintenance. To address these questions, we analyzed whole mount preparations of the lateral ventricle by confocal microscopy using different extracellular matrix and cell markers. We found that bulbs are rarely connected to stems and that they contain laminin α5 and α2 chains, respectively. Fractone bulbs were profusely distributed throughout the SVZ and appeared associated with the center of pinwheels, a critical site for adult neurogenesis. We demonstrate that bulbs appear at the apical membrane of ependymal cells at the end of the first week after birth. The use of transgenic mice lacking laminin α5 gene expression (Lama5) in endothelium and in FoxJ1-expressing ependymal cells, revealed ependymal cells as the source of laminin α5-containing fractone bulbs. Loss of laminin α5 from bulbs correlated with a 60% increase in cell proliferation, as determined by PH3 staining, and with a selective reduction in the number of quiescent neural stem cells in the SVZ. These results indicate that fractones are a key component of the SVZ and suggest that laminin α5 modulates the physiology of the neural stem cell niche.Significance StatementOur work unveils key aspects of fractones, extracellular matrix structures present in the SVZ that still lack a comprehensive characterization. We show that fractones extensively interact with neural stem cells, whereas some of them are located precisely at pinwheel centers, which are hotspots for adult neurogenesis. Our results also demonstrate that fractones increase in size during aging and that their interactions with NSPCs become more complex in old mice. Lastly, we show that fractone bulbs are produced by ependymal cells and that their laminin content regulates neural stem cells.


2014 ◽  
Vol 3 (9) ◽  
pp. 1457-1464 ◽  
Author(s):  
Yoojin Shin ◽  
Kisuk Yang ◽  
Sewoon Han ◽  
Hyun-Ji Park ◽  
Yun Seok Heo ◽  
...  

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