scholarly journals Mechanical stimulation of single cells by reversible host-guest interactions in 3D microscaffolds

2020 ◽  
Vol 6 (39) ◽  
pp. eabc2648
Author(s):  
Marc Hippler ◽  
Kai Weißenbruch ◽  
Kai Richler ◽  
Enrico D. Lemma ◽  
Masaki Nakahata ◽  
...  
Keyword(s):  
Single Cells ◽  
Three Dimensional ◽  
Stimuli Responsive ◽  
Traction Forces ◽  
Set Point ◽  
Cellular Processes ◽  
Laser Lithography ◽  
Cross Links ◽  
Tensional Homeostasis ◽  
Myosin Motors

Many essential cellular processes are regulated by mechanical properties of their microenvironment. Here, we introduce stimuli-responsive composite scaffolds fabricated by three-dimensional (3D) laser lithography to simultaneously stretch large numbers of single cells in tailored 3D microenvironments. The key material is a stimuli-responsive photoresist containing cross-links formed by noncovalent, directional interactions between β-cyclodextrin (host) and adamantane (guest). This allows reversible actuation under physiological conditions by application of soluble competitive guests. Cells adhering in these scaffolds build up initial traction forces of ~80 nN. After application of an equibiaxial stretch of up to 25%, cells remodel their actin cytoskeleton, double their traction forces, and equilibrate at a new dynamic set point within 30 min. When the stretch is released, traction forces gradually decrease until the initial set point is retrieved. Pharmacological inhibition or knockout of nonmuscle myosin 2A prevents these adjustments, suggesting that cellular tensional homeostasis strongly depends on functional myosin motors.

Dysregulation of HOX as a Potential Therapeutic Target in Breast Cancer

2020 ◽  
Vol 27 ◽  
Author(s):  
Ji-Yeon Lee ◽  
Myoung Hee Kim
Keyword(s):  
Breast Cancer ◽  
Hox Genes ◽  
Therapeutic Potential ◽  
Expression Patterns ◽  
Genome Structure ◽  
Control Cell ◽  
Three Dimensional ◽  
Cellular Processes ◽  
Hox Protein

: HOX genes belong to the highly conserved homeobox superfamily, responsible for the regulation of various cellular processes that control cell homeostasis, from embryogenesis to carcinogenesis. The abnormal expression of HOX genes is observed in various cancers, including breast cancer; they act as oncogenes or as suppressors of cancer, according to context. In this review, we analyze HOX gene expression patterns in breast cancer and examine their relationship, based on the three-dimensional genome structure of the HOX locus. The presence of non-coding RNAs, embedded within the HOX cluster, and the role of these molecules in breast cancer have been reviewed. We further evaluate the characteristic activity of HOX protein in breast cancer and its therapeutic potential.

Three-dimensional SiO2 surface structures fabricated using femtosecond laser lithography

2009 ◽  
Vol 98 (1) ◽  
pp. 171-177 ◽  
Author(s):  
Mizue Mizoshiri ◽  
Hiroaki Nishiyama ◽  
Junji Nishii ◽  
Yoshinori Hirata
Keyword(s):  
Femtosecond Laser ◽  
Three Dimensional ◽  
Surface Structures ◽  
Sio2 Surface ◽  
Laser Lithography

scholarly journals Protease-dependent versus -independent cancer cell invasion programs: three-dimensional amoeboid movement revisited

2009 ◽  
Vol 185 (1) ◽  
pp. 11-19 ◽  
Author(s):  
Farideh Sabeh ◽  
Ryoko Shimizu-Hirota ◽  
Stephen J. Weiss
Keyword(s):  
Cancer Cells ◽  
Type I Collagen ◽  
Three Dimensional ◽  
Amoeboid Movement ◽  
Type I ◽  
Collagen Network ◽  
Normal Tissues ◽  
Tissue Invasion ◽  
Absolute Requirement ◽  
Cross Links

Tissue invasion during metastasis requires cancer cells to negotiate a stromal environment dominated by cross-linked networks of type I collagen. Although cancer cells are known to use proteinases to sever collagen networks and thus ease their passage through these barriers, migration across extracellular matrices has also been reported to occur by protease-independent mechanisms, whereby cells squeeze through collagen-lined pores by adopting an ameboid phenotype. We investigate these alternate models of motility here and demonstrate that cancer cells have an absolute requirement for the membrane-anchored metalloproteinase MT1-MMP for invasion, and that protease-independent mechanisms of cell migration are only plausible when the collagen network is devoid of the covalent cross-links that characterize normal tissues.

scholarly journals Systematic functional characterization of antisense eRNA of protocadherin α composite enhancer

2021 ◽  
Vol 35 (19-20) ◽  
pp. 1383-1394
Author(s):  
Yuxiao Zhou ◽  
Siyuan Xu ◽  
Mo Zhang ◽  
Qiang Wu
Keyword(s):  
Gene Expression ◽  
Molecular Mechanisms ◽  
Single Cells ◽  
Functional Characterization ◽  
Three Dimensional ◽  
Elongation Factor ◽  
Locked Nucleic Acid ◽  
Loop Formation ◽  
Long Distance ◽  
Enhancer Region

Enhancers generate bidirectional noncoding enhancer RNAs (eRNAs) that may regulate gene expression. At present, the eRNA function remains enigmatic. Here, we report a 5′ capped antisense eRNA PEARL (Pcdh eRNA associated with R-loop formation) that is transcribed from the protocadherin (Pcdh) α HS5-1 enhancer region. Through loss- and gain-of-function experiments with CRISPR/Cas9 DNA fragment editing, CRISPRi, and CRISPRa, as well as locked nucleic acid strategies, in conjunction with ChIRP, MeDIP, DRIP, QHR-4C, and HiChIP experiments, we found that PEARL regulates Pcdhα gene expression by forming local RNA–DNA duplexes (R-loops) in situ within the HS5-1 enhancer region to promote long-distance chromatin interactions between distal enhancers and target promoters. In particular, increased levels of eRNA PEARL via perturbing transcription elongation factor SPT6 lead to strengthened local three-dimensional chromatin organization within the Pcdh superTAD. These findings have important implications regarding molecular mechanisms by which the HS5-1 enhancer regulates stochastic Pcdhα promoter choice in single cells in the brain.

scholarly journals Collective forces of tumor spheroids in three-dimensional biopolymer networks

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Christoph Mark ◽  
Thomas J Grundy ◽  
Pamela L Strissel ◽  
David Böhringer ◽  
Nadine Grummel ◽  
...  
Keyword(s):  
Single Cells ◽  
Three Dimensional ◽  
Traction Force ◽  
Tumor Spheroids ◽  
Scale Invariant ◽  
Tissue Samples ◽  
Force Microscopy ◽  
Surrounding Matrix ◽  
Highly Nonlinear ◽  
Contractile Forces

We describe a method for quantifying the contractile forces that tumor spheroids collectively exert on highly nonlinear three-dimensional collagen networks. While three-dimensional traction force microscopy for single cells in a nonlinear matrix is computationally complex due to the variable cell shape, here we exploit the spherical symmetry of tumor spheroids to derive a scale-invariant relationship between spheroid contractility and the surrounding matrix deformations. This relationship allows us to directly translate the magnitude of matrix deformations to the total contractility of arbitrarily sized spheroids. We show that our method is accurate up to strains of 50% and remains valid even for irregularly shaped tissue samples when considering only the deformations in the far field. Finally, we demonstrate that collective forces of tumor spheroids reflect the contractility of individual cells for up to 1 hr after seeding, while collective forces on longer timescales are guided by mechanical feedback from the extracellular matrix.

scholarly journals E11/gp38 Selective Expression in Osteocytes: Regulation by Mechanical Strain and Role in Dendrite Elongation

2006 ◽  
Vol 26 (12) ◽  
pp. 4539-4552 ◽  
Author(s):  
Keqin Zhang ◽  
Cielo Barragan-Adjemian ◽  
Ling Ye ◽  
Shiva Kotha ◽  
Mark Dallas ◽  
...  
Keyword(s):  
Shear Stress ◽  
Cell Lines ◽  
Mechanical Load ◽  
Mechanical Strain ◽  
Three Dimensional ◽  
Cell Communication ◽  
Bone Surface ◽  
Cellular Processes ◽  
Primary Osteoblasts

ABSTRACT Within mineralized bone, osteocytes form dendritic processes that travel through canaliculi to make contact with other osteocytes and cells on the bone surface. This three-dimensional syncytium is thought to be necessary to maintain viability, cell-to-cell communication, and mechanosensation. E11/gp38 is the earliest osteocyte-selective protein to be expressed as the osteoblast differentiates into an osteoid cell or osteocyte, first appearing on the forming dendritic processes of these cells. Bone extracts contain large amounts of E11, but immunostaining only shows its presence in early osteocytes compared to more deeply embedded cells, suggesting epitope masking by mineral. Freshly isolated primary osteoblasts are negative for E11 expression but begin to express this protein in culture, and expression increases with time, suggesting differentiation into the osteocyte phenotype. Osteoblast-like cell lines 2T3 and Oct-1 also show increased expression of E11 with differentiation and mineralization. E11 is highly expressed in MLO-Y4 osteocyte-like cells compared to osteoblast cell lines and primary osteoblasts. Differentiated, mineralized 2T3 cells and MLO-Y4 cells subjected to fluid flow shear stress show an increase in mRNA for E11. MLO-Y4 cells show an increase in dendricity and elongation of dendrites in response to shear stress that is blocked by small interfering RNA specific to E11. In vivo, E11 expression is also increased by a mechanical load, not only in osteocytes near the bone surface but also in osteocytes more deeply embedded in bone. Maximal expression is observed not in regions of maximal strain but in a region of potential bone remodeling, suggesting that dendrite elongation may be occurring during this process. These data suggest that osteocytes may be able to extend their cellular processes after embedment in mineralized matrix and have implications for osteocytic modification of their microenvironment.

scholarly journals Three Dimensional Traction Forces Exerted by Migrating Amoeboid Cells

2012 ◽  
Vol 102 (3) ◽  
pp. 704a
Author(s):  
Begona Alvarez-Gonzalez ◽  
Juan C. del Alamo ◽  
Ruedi Meili ◽  
Baldomero Alonso-Latorre ◽  
Richard Firtel ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Traction Forces ◽  
Amoeboid Cells
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