RNA sequencing to study transcriptomic changes in DLD-1 (colorectal adenocarcinoma) cells exposed to soft polyacrylamide matrices (~2 kPa and ~55 kPa) for short time scale of 90 minutes

Aim: To examine transcriptional changes in DLD-1 cells exposed to softer matrices (2 kPa and 55 kPa) and identify the chromosomes that are enriched with maximmally deregulated genes Methods: DLD-1 cells (otherwise growing on stiff tissue culture plastic substrates) were exposed to softer matrices for 90 minutes and to collagen coated glass coverslips (served as control) served as control) Results: RNA sequencing revealed nearly equivalent transcriptional deregulation in cells on both the polyacrylamide matrices (783 genes up and 872 genes down on 2 kPa, 649 genes up and 783 genes down on 55 kPa) when compared to cells on glass. Additionally, GO classification revealed that unique sets of transcriptionally deregulated genes (log fold=2) belonged to pathways associated with transcription regulation, chromatin organization, cell cycle and DNA damage/repair Results: We identified chromosomes 1, 2, 3, 6, 7, 10, 12, 14, 17 and 19 to be maximally enriched with the deregulated genes on softer matrices (log fold=2), while chromosomes 13, 18 and 21 showed minimal enrichment of deregulated genes. We also examined the spatial organization of chromosome 1, 18 and 19 territories in cells on softer matrices (using 3D-FISH) and observed that these chromosomes were mislocalized away from their conserved nuclear locations Conclusions: Our study reports the transcriptomic changes in DLD-1 cells upon lowering of extracellular substrate stiffnes and its impact on the spatial positioning of chromosome territories Overall design: RNA Seq profiles for DLD-1 cells on soft polyacrylamide matrices of ~2 kPa and ~55 kPa (reference - glass) were generated across 2 independent biological replicates using Illumina HiSeq platform

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Pradhan R, Ranade D, Sengupta K