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The Topoisomerase II Catalytic Inhibitor ICRF-193 Preferentially Targets Telomeres That Are Capped by TRF2

Lianxiang Chen, Xiaowei Zhu, Yaru Zou, Jun Xing, Eric Gilson, Yiming Lu, Jing Ye

Am J Physiol Cell Physiol. 2015 Mar 1;308(5):C372-7.

PMID: 25518961

Abstract:

The increased level of chromosome instability in cancer cells is not only a driving force for oncogenesis but also can be the Achille's heel of the disease since many chemotherapies kill cells by inducing a nontolerable rate of DNA damage. A wealth of published evidence showed that telomere stability can be more affected than the bulk of the genome by several conventional antineoplastic drugs. In the present study, HT1080 cell lines compromised for either telomere repeats binding factor 2 (TRF2) or POT1 were treated with ICRF-193 (3 μM, 24 h) or bleomycin (1 μM, 24 h). DNA damage was assayed by combining telomeric DNA staining of a (CCCTAA)n PNA probe with immunofluorescence of 53BP1 to score the rate of telomere colocalization with 53BP1 foci. We found that ICRF-193, but not bleomycin, leads to DNA damage preferentially at telomeres, which can be rescued by TRF2 inhibition. POT1 inhibition exacerbates telomere dysfunction induced by ICRF-193. Thus, ICRF-193 induces damage at telomeres properly capped by TRF2 but not by POT1. These findings are expected to broaden our view on the mechanism by which conventional therapeutic molecules act to eliminate cancer cells and how to use TRF2 and POT1 levels as surrogate markers for anti-topoisomerase II sensitivity.

Chemicals Related in the Paper:

Catalog Number Product Name Structure CAS Number Price
AP21416886 ICRF-193 ICRF-193 21416-88-6 Price
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