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bioRxiv · 10.1101/035626

Constricted cell migration causes nuclear lamina damage, DNA breaks, and squeeze-out of repair factors

Jerome Irianto·Charlotte R Pfeifer·Yuntao Xia·Avathamsa Athirasala·Irena L Ivanovska·Roger E Greenberg·Dennis E Discher
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Abstract

Genomic variation across cancers scales with tissue stiffness: meta-analyses show tumors in stiff tissues such as lung and bone exhibit up to 100-fold more variation than tumors in soft tissues such as marrow and brain. Here, nuclear lamina damage and DNA double-strand breaks (DSBs) result from invasive migration of cancer cells through stiff constrictions. DSBs increase with lamin-A knockdown and require micro-pores sufficiently small for lamins to impede migration. Blebs in the vast majority of post-migration nuclei are enriched in lamin-A but deficient in lamin-B and an age-associated form of lamin-A. Validation of DSBs by an electrophoretic comet assay calibrates against a cancer line having nuclease sites engineered in chromosome-1, and DSB-bound repair factors in nuclei pulled into constrictions show folded chromatin orients, extends, and concentrates without fragmentation. Mobile repair proteins simultaneously segregate away from pore-condensed chromatin. Global squeeze-out of repair factors and loss with lamin-A-dependent rupture explains why overexpression of repair factors cannot rescue DSBs in migration through stiff constrictions, ultimately favoring genomic variation.

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Jerome Irianto, Charlotte R Pfeifer, Yuntao Xia, Avathamsa Athirasala, Irena L Ivanovska, Roger E Greenberg, Dennis E Discher. 2015-12-30. Constricted cell migration causes nuclear lamina damage, DNA breaks, and squeeze-out of repair factors. https://doi.org/10.1101/035626

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