Micropillar-based phenotypic screening platform uncovers involvement of HDAC2 in nuclear deformability

Nuclear deformability is an essential feature of migratory cells. Intercellular movement and migration in the extracellular space requires cells to squeeze through constrictions up to an order of magnitude smaller than the average diameter of their biggest and stiffest organelle. One field of study in which aberrant nuclear shapes and deformability are of particular interest is cancer, with abnormal nuclear structures described as a hallmark of the disease and an indicator of pathological progression, while increased nuclear deformability correlates with increased metastatic potential. While most previous studies focused on the description of nuclear morphology in adaptation to different 3D geometries, and mechanistic investigations of nuclear deformation have been limited to contributions of the cytoskeleton, we tap for the first time into the potential of micropillared substrates to serve as drug screening platforms for compounds that influence nuclear deformability. To this end, we combine a micropillared culture substrate with image analyses to test the effect of various drugs on nuclear deformability and successfully identify histone deacetylases inhibitors (iHDACs) as active compounds in nuclear shape regulation on micropillars. Our experiments show that HDAC-activity as gene transcription regulators appears to activate a nuclear shape-rescue program in osteosarcoma cells, providing an excellent platform for identification of novel nuclear shape-determinants and possibly druggable targets for anti-cancer therapies. Examination of 4 replicates of SaOS-2 cells cultured for 48 h on flat or micropillared PDMS substrates. Each replicate represents a different cell passage within a paired design.