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Biology subjects

Shamsan, G. A.

Publications and source records attributed to Shamsan, G. A..

2 recordsLinked to original sources

RAD-TGTs: Measurement of cellular tensions via flow cytometry and DNA sequencing enabled by force-dependent rupture and delivery of DNA tension probes

Mechanical force is a key driver of cellular processes and is dysregulated in many diseases. Measuring cellular tensions to elucidate mechanotransduction pathways typically involves high-resolution but low throughput imaging of surfaces and arduous experimental preparation of materials. We present here Rupture and Deliver DNA-duplex based molecular tension sensors-RAD-TGTs. RAD-TGTs consist of immobilized DNA duplexes conjugated to a ligand and indicator (fluorophore, barcode etc) which rupture in a force-dependent manner when cells are bound. Readout of rupture is performed in cells of interest using high throughput methods such as flow cytometry and leveraging covalent DNA-protein linking HUH-tags simplifies the preparation of the tension sensor to allow use of "off-the-shelf" oligos. We demonstrate that rupture and delivery is decreased by inhibitors of cytoskeletal dynamics and knockout of mechanosensing proteins. We also show that rupture and delivery correlates with ligand affinity. Excitingly, we demonstrate that rupture and delivery of barcoded DNA-duplexes can be quantified using DNA sequencing, propelling cellular force measurements into the -omics era.

biophysics↗

Differential migration mechanics and immune responses of glioblastoma subtypes

Glioblastoma remains a deadly cancer driven in part by invasion of tumor cells into the brain. Transcriptomic analyses have identified distinct molecular subtypes, but mechanistic differences that account for clinical differences are not clear. Here, we show that, as predicted by the motor-clutch model of cell migration, mesenchymal glioma cells are more spread, generate larger traction forces, and migrate faster in brain tissue compared to proneural cells. Despite their rapid migration and comparable proliferation rates in vitro, mice with mesenchymal tumors survive longer than those with proneural tumors. This improved survival correlated with an immune response in the mesenchymal tumors, including T cell-mediated. Consistently, inducing mesenchymal tumors in immunodeficient mice resulted in shorter survival supporting a protective immune role in mesenchymal tumors. Thus, mesenchymal tumors have aggressive migration, but are immunologically hot which suppresses net proliferation. These two features counteract each other and may explain the lack of a strong survival difference between subtypes clinically, while also opening up new opportunities for subtype-specific therapies. Significant StatementThis study highlights new mechanical and immunological insights into glioblastoma molecular subtypes using an integrated modeling-genome engineering strategy, which can potentially facilitate glioblastoma subtype-specific therapeutic strategies.

cancer biology↗