Depletion of tyrosyl DNA phosphodiesterase 2 activity enhances etoposide-mediated double-strand break formation and cell killing

Kont Y., Dutta A., Mallisetty A., Mathew J., Minas T., Kraus C., ...Daha Fazla

DNA REPAIR, cilt.43, ss.38-47, 2016 (SCI-Expanded, Scopus)

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 43
  • Basım Tarihi: 2016
  • Doi Numarası: 10.1016/j.dnarep.2016.04.009
  • Dergi Adı: DNA REPAIR
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Sayfa Sayıları: ss.38-47
  • Anahtar Kelimeler: DNA repair, Enzyme assay, TDP2, High throughput screening, Molecular probe, Inhibitor, NSC111041, TOPOISOMERASE-II, APURINIC/APYRIMIDINIC ENDONUCLEASE, ANTICANCER THERAPY, REPAIR, DAMAGE, GLYCOSYLASE, INHIBITORS, BINDING, CANCER, DISCRIMINATION
  • Çukurova Üniversitesi Adresli: Hayır

Özet

DNA topoisomerase 2 (Top2) poisons, including common anticancer drugs etoposide and doxorubicin kill cancer cells by stabilizing covalent Top2-tyrosyl-DNA 5'-phosphodiester adducts and DNA double-strand breaks (DSBs). Proteolytic degradation of the covalently attached Top2 leaves a 5'-tyrosylated blocked termini which is removed by tyrosyl DNA phosphodiesterase 2 (TDP2), prior to DSB repair through non homologous end joining (NHEJ). Thus, TDP2 confers resistance of tumor cells to Top2-poisons by repairing such covalent DNA-protein adducts, and its pharmacological inhibition could enhance the efficacy of Top2-poisons. We discovered NSC111041, a selective inhibitor of TDP2, by optimizing a high throughput screening (HTS) assay for TDP2's 5'-tyrosyl phosphodiesterase activity and subsequent validation studies. We found that NSC111041 inhibits TDP2's binding to DNA without getting intercalated into DNA and enhanced etoposide's cytotoxicity synergistically in TDP2-expressing cells but not in TDP2 depleted cells. Furthermore, NSC111041 enhanced formation of etoposide-induced gamma-H2AX foci presumably by affecting DSB repair. Immuno-histochemical analysis showed higher TDP2 expression in a sub-set of different type of tumor tissues. These findings underscore the feasibility of clinical use of suitable TDP2 inhibitors in adjuvant therapy with Top2-poisons for a sub-set of cancer patients with high TDP2 expression. (C) 2016 Elsevier B.V. All rights reserved.

DNA topoisomerase 2 (Top2) poisons, including common anticancer drugs etoposide and doxorubicin kill cancer cells by stabilizing covalent Top2-tyrosyl-DNA 5'-phosphodiester adducts and DNA double-strand breaks (DSBs). Proteolytic degradation of the covalently attached Top2 leaves a 5'-tyrosylated blocked termini which is removed by tyrosyl DNA phosphodiesterase 2 (TDP2), prior to DSB repair through non homologous end joining (NHEJ). Thus, TDP2 confers resistance of tumor cells to Top2-poisons by repairing such covalent DNA-protein adducts, and its pharmacological inhibition could enhance the efficacy of Top2-poisons. We discovered NSC111041, a selective inhibitor of TDP2, by optimizing a high throughput screening (HTS) assay for TDP2's 5'-tyrosyl phosphodiesterase activity and subsequent validation studies. We found that NSC111041 inhibits TDP2's binding to DNA without getting intercalated into DNA and enhanced etoposide's cytotoxicity synergistically in TDP2-expressing cells but not in TDP2 depleted cells. Furthermore, NSC111041 enhanced formation of etoposide-induced gamma-H2AX foci presumably by affecting DSB repair. Immuno-histochemical analysis showed higher TDP2 expression in a sub-set of different type of tumor tissues. These findings underscore the feasibility of clinical use of suitable TDP2 inhibitors in adjuvant therapy with Top2-poisons for a sub-set of cancer patients with high TDP2 expression. (C) 2016 Elsevier B.V. All rights reserved.