eprintid: 10117135 rev_number: 14 eprint_status: archive userid: 608 dir: disk0/10/11/71/35 datestamp: 2020-12-14 11:25:26 lastmod: 2021-10-09 22:31:26 status_changed: 2020-12-14 11:25:26 type: article metadata_visibility: show creators_name: Ahmed, AA creators_name: Neidle, S title: A G-Quadruplex-Binding Small Molecule and the HDAC Inhibitor SAHA (Vorinostat) Act Synergistically in Gemcitabine-Sensitive and Resistant Pancreatic Cancer Cells ispublished: pub divisions: UCL divisions: B02 divisions: C08 divisions: D10 keywords: CM03, drug synergy, gemcitabine resistance, histone deacetylase (HDAC) inhibitor vorinostat, naphthalene diimide derivative, pancreatic cancer, quadruplex note: © 2020 by the Authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). abstract: The stabilisation of G-quadruplexes (G4s) by small-molecule compounds is an effective approach for causing cell growth arrest, followed by cell death. Some of these compounds are currently being developed for the treatment of human cancers. We have previously developed a substituted naphthalene diimide G4-binding molecule (CM03) with selective potency for pancreatic cancer cells, including gemcitabine-resistant cells. We report here that CM03 and the histone deacetylase (HDAC) inhibitor SAHA (suberanilohydroxamic acid) have synergistic effects at concentrations close to and below their individual GI_{50} values, in both gemcitabine-sensitive and resistant pancreatic cancer cell lines. Immunoblot analysis showed elevated levels of γ-H2AX and cleaved PARP proteins upon drug combination treatment, indicating increased levels of DNA damage (double-strand break events: DSBs) and apoptosis induction, respectively. We propose that the mechanism of synergy involves SAHA relaxing condensed chromatin, resulting in higher levels of G4 formation. In turn, CM03 can stabilise a greater number of G4s, leading to the downregulation of more G4-containing genes as well as a higher incidence of DSBs due to torsional strain on DNA and chromatin structure. date: 2020-11-02 date_type: published official_url: https://doi.org/10.3390/molecules25225407 oa_status: green full_text_type: pub pmcid: PMC7699281 language: eng primo: open primo_central: open_green verified: verified_manual elements_id: 1832683 doi: 10.3390/molecules25225407 pii: molecules25225407 lyricists_name: Neidle, Stephen lyricists_id: SNEID18 actors_name: Neidle, Stephen actors_name: Harris, Jean actors_id: SNEID18 actors_id: JAHAR68 actors_role: owner actors_role: impersonator full_text_status: public publication: Molecules volume: 25 number: 22 article_number: 5407 event_location: Switzerland citation: Ahmed, AA; Neidle, S; (2020) A G-Quadruplex-Binding Small Molecule and the HDAC Inhibitor SAHA (Vorinostat) Act Synergistically in Gemcitabine-Sensitive and Resistant Pancreatic Cancer Cells. Molecules , 25 (22) , Article 5407. 10.3390/molecules25225407 <https://doi.org/10.3390/molecules25225407>. Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/10117135/1/molecules-25-05407-v2.pdf