Extracellular matrix stiffness determines DNA repair efficiency and cellular sensitivity to genotoxic agents

Abstract

DNA double-strand breaks (DSBs) are highly toxic lesions that can drive genetic instability. These lesions also contribute to the efficacy of radiotherapy and many cancer chemotherapeutics. DNA repair efficiency is regulated by both intracellular and extracellular chemical signals. However, it is largely unknown whether this process is regulated by physical stimuli such as extracellular mechanical signals. Here, we report that DSB repair is regulated by extracellular mechanical signals. Low extracellular matrix (ECM) stiffness impairs DSB repair and renders cells sensitive to genotoxic agents. Mechanistically, we found that the MAP4K4/6/7 kinases are activated and phosphorylate ubiquitin in cells at low stiffness. Phosphorylated ubiquitin impairs RNF8-mediated ubiquitin signaling at DSB sites, leading to DSB repair deficiency. Our results thus demonstrate that ECM stiffness regulates DSB repair efficiency and genotoxic sensitivity through MAP4K4/6/7 kinase–mediated ubiquitin phosphorylation, providing a previously unidentified regulation in DSB-induced ubiquitin signaling.

Linking Oxidative Stress and DNA Damage to Changes in the Expression of Extracellular Matrix Components

“…The importance of ECM biomechanical properties goes beyond maintaining mitochondrial stability. Low ECM stiffness compromises the DNA damage response, making cells more sensitive to DNA damaging agents ( Deng et al, 2020 ), while high ECM stiffness promotes nuclear rupture also leading to increased DNA damage ( Cho et al, 2019 ; Figure 3B ). Altogether, these studies suggest that countering mitochondrial dysfunction, and possibly preventing DNA damage, may be a promising strategy to revert the pathology caused by some mutations in genes encoding ECM components, their receptors or molecules that bridge ECM receptors to the cell cytoskeleton.…”

USP37 regulates DNA damage response through stabilizing and deubiquitinating BLM

“…In vitro kinase assays were performed as described previously ( 33 ). Breifly, purified WT-USP37, S114A or S114E mutant was incubated with ATM at 30°C in buffers containing [25 mM Tris–HCl (pH 7.4), 2 mM adenosine 5′-triphosphate (ATP), 5 mM MgCl 2 , 5 mM MnCl 2 and 0.1 mM dithiothreitol (DTT)] for in vitro kinase assay,…”

Microenvironmental control of cell fate decisions in mammary gland development and cancer

“…Importantly, obesity also leads to increased mammary interstitial fibrosis, which results in increased ECM stiffness and altered mechanosignaling, ultimately promoting tumorigenesis (Seo et al, 2015). Increased ECM stiffness also leads to impaired repair of DNA double-strand breaks due to deficient breast cancer type 1 susceptibility protein (BRCA1) and tumor suppressor p53-binding protein 1 (53BP1) recruitment (Deng et al, 2020). The dual role of BRCA1 in DNA damage response and in cell differentiation is discussed in further detail below.…”