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PAUL, D.

Publications and source records attributed to PAUL, D..

2 recordsLinked to original sources

Hyaluronan Surface Architecture Dictates Colorectal Cancer Progression and Extracellular Vesicle Communication

Hyaluronan (HA) is a principal component of the tumor glycocalyx in colorectal cancer (CRC). However, how the disease progression is linked to HA abundance and its nanoscale organization remains unclear. Single-molecule measurements of surface glycans on cell membranes and extracellular vesicles (EVs) have not yet been correlated. In this work, using single-molecule force spectroscopy, we mapped HA density and chain length on CRC cells and their EVs across Dukes' stages. HA density increased with stage in both compartments, but their organization diverged. Cell-surface HA became progressively fragmented, whereas EVs remained enriched in short HA chains at every stage. EVs, therefore, appear to select HA during formation rather than inherit it from the parent cell. This divergence had mechanical consequences. Both cells and EVs softened with stage, and removing HA reversed this softening. In addition, coarse-grained membrane simulations revealed that both HA chain length and surface density regulate membrane wrapping, with chain length primarily influencing wrapping kinetics and surface density affecting the final wrapping extent. These findings provide a physical basis for the differences we observed in EV uptake. Reprogramming stage D cells with exogenous high-molecular-weight HA reversed this signature, lowering EV surface HA density, stiffening the vesicles, slowing migration, and suppressing EV uptake by recipient cells. These findings establish HA surface architecture as a stage-encoded and experimentally reversible determinant of CRC progression.

biophysics↗

Valproic Acid Treatment Enhances Chromosome Flexibility and Electron Transport in MCF7 Breast Cancer Cells

The structural integrity of the chromosomes is essential to every functional process within the eukaryotic nuclei. Chromosomes are DNA-histone complexes essential for the inheritance of genetic information to the offspring and any defect in it is linked to mitotic errors, cancer growth, and cellular aging. Changes in the mechanical properties of a chromosome could lead to its compromised function and stability, leading to chromosome breaks. Here, we studied the changes in chromosome physical properties using metaphase chromosomes isolated from human breast cancer cells (MCF7) exposed to Valproic Acid (VPA), a known epigenetic modifier drug involved in histone hyperacetylation and DNA demethylation. Due to chromosomal structural intricacy, preparative and technical limitations of analytical tools, we employed a label-free atomic force microscopy approach for simultaneously visualizing and mapping single chromosome elasticity. Additionally, we performed electron transport characteristics of metaphase chromosomes to elucidate the effect of VPA. Our multi-parametric strategy of probing physical properties of chromosomes offers a new scope in terms of analytical tools for studying chromosomal structural changes/aberrations and associated structure-function relationships pertinent to cancer.

biophysics↗