Generation of a novel model of primary human cell senescence through Tenovin-6 mediated inhibition of sirtuins

Hannah E Walters,Lynne S Cox

doi:10.1007/s10522-018-09792-0

Abstract

Cell senescence, a state of cell cycle arrest and altered metabolism with enhanced pro-inflammatory secretion, underlies at least some aspects of organismal ageing. The sirtuin family of deacetylases has been implicated in preventing premature ageing; sirtuin overexpression or resveratrol-mediated activation of sirtuins increase longevity. Here we show that sirtuin inhibition by short-term, low-dose treatment with the experimental anti-cancer agent Tenovin-6 (TnV6) induces cellular senescence in primary human fibroblasts. Treated cells cease proliferation and arrest in G1 of the cell cycle, with elevated p21 levels, DNA damage foci, high mitochondrial and lysosomal load and increased senescence-associated β galactosidase activity, together with actin stress fibres and secretion of IL-6 (indicative of SASP upregulation). Consistent with a histone deacetylation role of SIRT1, we find nuclear enlargement, possibly resulting from chromatin decompaction on sirtuin inhibition. These findings highlight TnV6 as a drug that may be useful in clinical settings where acute induction of cell senescence would be beneficial, but also provide the caveat that even supposedly non-genotoxic anticancer drugs can have unexpected and efficacy-limiting impacts on non-transformed cells.

Highlights

Cellular senescence is an essentially irreversible proliferation arrest mechanism induced by various stress signals, such as telomere attrition or oncogene activation, and is causally linked to ageing and the development of age-related diseases (Baker et al 2016; Xu et al 2018)
Evolution of a fluorescent signal from TnV6-treated cells was compared with cells treated with resveratrol (RSV), an histone deacetylase (HDAC)/SIRT1 activator, vehicle only (DMSO) negative controls and HDAC inhibitor trichostatin A (TSA)
Treatment with resveratrol led to increased deacetylation of the substrate in this assay, which was especially notable in HeLa cells (Fig. 1), while the positive control HDAC inhibitor TSA only led to a small decrease in deacetylation in HF043 cells at the recommended dose

Summary

Introduction

Cellular senescence is an essentially irreversible proliferation arrest mechanism induced by various stress signals, such as telomere attrition or oncogene activation, and is causally linked to ageing and the development of age-related diseases (Baker et al 2016; Xu et al 2018). While a multitude of signalling pathways can induce senescence, p53 is a crucial mediator, driving upregulation of p21CDNK1A to induce proliferation arrest upon detection of stress (Munoz-Espin and Serrano 2014). Mice overexpressing SIRT1 in the brain have extended lifespan (Satoh et al 2013), and small molecule SIRT1 activators SRT2104 and SRT1720 extend lifespan (Mercken et al 2014; Mitchell et al 2014). No positive effect on longevity was detected on resveratrol feeding to mice in the highly powered multisite Interventions Testing Program (Miller et al 2011)

Methods

Results

Conclusion