Cell-based chemical fingerprinting identifies telomeres and lamin A as modifiers of DNA damage response in cancer cells

Chiaki Fujiwara,Yukiko Muramatsu,Hidetoshi Tahara,Hiroyuki Seimiya,Takao Yamori,Masaru Ueno,Megumi Nishii,Yoshikazu Sugimoto,Kazuhiro Tokunaka

doi:10.1038/s41598-018-33139-x

Abstract

Telomere maintenance by telomerase activity supports the infinite growth of cancer cells. MST-312, a synthetic telomerase inhibitor, gradually shortens telomeres at non-acute lethal doses and eventually induces senescence and apoptosis of telomerase-positive cancer cells. Here we report that MST-312 at higher doses works as a dual inhibitor of telomerase and DNA topoisomerase II and exhibits acute anti-proliferative effects on cancer cells and xenografted tumours in vivo. Our cell-based chemical fingerprinting approach revealed that cancer cells with shorter telomeres and lower expression of lamin A, a nuclear architectural protein, exhibited higher sensitivity to the acute deleterious effects of MST-312, accompanied by formation of telomere dysfunction-induced foci and DNA double-strand breaks. Telomere elongation and lamin A overexpression attenuated telomeric and non-telomeric DNA damage, respectively, and both conferred resistance to apoptosis induced by MST-312 and other DNA damaging anticancer agents. These observations suggest that sufficient pools of telomeres and a nuclear lamina component contribute to the cellular robustness against DNA damage induced by therapeutic treatment in human cancer cells.

Highlights

Telomeres are protective structures at the ends of eukaryotic linear chromosomes that consist of telomeric DNA, (TTAGGG)n, and binding proteins, such as shelterin[1]
In vast majority of human cancer cells, the end replication problem is solved by the maintenance of telomeres by the telomerase enzyme[6], which consists of the hTERT catalytic subunit and the RNA template
We examined the effects of the synthetic telomerase inhibitor MST-312 at higher doses than those in our previous reports[14,16] and focused on the molecular mechanism for the acute cancer cell growth inhibition induced by high MST-312 concentrations

Summary

Introduction

Telomeres are protective structures at the ends of eukaryotic linear chromosomes that consist of telomeric DNA, (TTAGGG)n, and binding proteins, such as shelterin[1]. We examined the effects of the synthetic telomerase inhibitor MST-312 at higher doses than those in our previous reports[14,16] and focused on the molecular mechanism for the acute cancer cell growth inhibition induced by high MST-312 concentrations. Among the cell lines with very short telomeres (i.e., the mean TRF length is less than 4 kb), there was an inverse correlation between telomerase activity and MST-312 sensitivity (r = −0.826, P = 0.0415, Supplementary Fig. S1C).

Results

Conclusion