Biology subjects

Danen, E. H.

Publications and source records attributed to Danen, E. H..

3 recordsLinked to original sources

bioRxiv2025

Matrix stiffness affects spheroid invasion, collagen remodeling and the effective reach of stress into the ECM.

The extracellular matrix (ECM) provides structural support to cells thereby forming a functional tissue. In cancer, the growth of the tumor creates an internal mechanical stress which, together with remodeling activity of tumor cells and fibroblasts, alters the ECM structure leading to an increased stiffness of the pathological ECM. The enhanced ECM stiffness in turn stimulates tumor growth, activates tumor-promoting fibroblasts and tumor cell migration, leading to metastasis and an increased therapy resistance. The connection between internal tumor stress, ECM stiffness, ECM remodeling, and cell migration are unresolved. Here we used 3D ECM-embedded spheroids and hydrogel-particle stress sensors, to quantify and correlate internal tumor-spheroid pressure, ECM stiffness, ECM remodeling, and tumor cell migration. 4T1 breast cancer spheroids and SV80 fibroblast spheroids showed increased invasion - described by area, complexity, number of branches and branch area - in a stiffer, cross-linked ECM. On the other hand, changing the ECM stiffness only minimally changed the radial alignment of fibers but highly changed the amount of fibers.. For both cell types, the pressure measured in spheroids gradually decreased as the distance into the ECM increased. For 4T1 spheroids, increased ECM stiffness resulted in a further reach of mechanical stress into the ECM which, together with the invasive phenotype, was reduced by inhibition of ROCK-mediated contractility. By contrast, such correlation between ECM stiffness and stress-reach was not observed for SV80 spheroids. Our findings connect ECM stiffness with tumor invasion, ECM remodeling, and the reach of tumor-induced mechanical stress into the ECM. Such mechanical connections between tumor and ECM are expected to drive early steps in cancer metastasis.

biophysics↗

bioRxiv2020

Genome-wide identification of binding sites of GRHL2 in luminal-like and basal A subtypes of breast cancer

Grainyhead like 2 (GRHL2) is one of three mammalian homologues of the grainyhead (GRH) gene. It suppresses the oncogenic epithelial-mesenchymal transition (EMT), acting as a tumor suppressor. On the other hand, GHRL2 promotes cell proliferation by increasing human telomerase reverse transcriptase (hTERT) activity, serving as a tumor promoter. According to gene expression profiling, breast cancer can be divided into basal-like (basal A and basal B), luminal-like, HER2 enriched, claudin-low and normal-like subtypes. To identify common and subtype-specific genomic binding sites of GRHL2 in breast cancer, GRHL2 ChIP-seq was performed in three luminal-like and three basal A human breast cancer cell lines. Most binding sites of GRHL2 were found in intergenic and intron regions. 13,351 common binding sites were identified in basal A cells, which included 551 binding sites in gene promoter regions. For luminal-like cells, 6,527 common binding sites were identified, of which 208 binding sites were found in gene promoter regions. Basal A and luminal-like breast cancer cells shared 4711 GRHL2 binding sites, of which 171 binding sites were found in gene promoter regions. The identified GRHL2-binding motifs are all identical to a motif reported for human ovarian cancer, indicating conserved GRHL2 DNA-binding among human cancer cells. Notably, no binding sites of GRHL2 were detected in the promoter regions of several established EMT-related genes, including CDH1, ZEB1, ZEB2 and CDH2 genes. Collectively, this study provides a comprehensive overview of interactions of GRHL2 with DNA and lays the foundation for further understanding of common and subtype-specific signaling pathways regulated by GRHL2 in breast cancer.

cancer biology↗

bioRxiv2018

p130Cas contributes to cellular mechanosensing and force exertion.

Cell survival, differentiation, and migration are all dependent on the cells interaction with its external environment. In addition to chemical cues, cells react to their physical environment, particularly the stiffness of the substrate. In order for cells to react to these elements, they must make use of cellular machinery to signal changes in their microenvironment. One such proposed machinery is the protein p130Cas, which has been shown to regulate focal adhesion turnover, actin dynamics, and cell migration. Here we show that p130Cas localizes to focal adhesions depending on substrate stiffness and subsequently modulates cellular force exertion. We compared on substrates of tunable stiffness knock-out CAS-/-cells to cells re-expressing either the full-length p130Cas or a mutant lacking the focal adhesion targeting domains. On polyacrylamide gels, we observed that p130Cas prevented focal adhesion formation at low stiffness. On structured micro-pillar arrays, p130Cas preferentially localized to sites of force exertion when the apparent Youngs modulus of the substrate was higher than E = 47 kPa. Stiffness-dependent localization of p130Cas coincided with slower, but increased force exertion for the full-length p130Cas. Cas localization to focal adhesions preceded force build-up by three minutes, suggesting a coordinating role for p130Cas in the cellular mechanoresponse. Thus, p130Cas appears to relay mechanosensory information in the cell through its ability to tune force exertion at the focal adhesion.

biophysics↗