2. Academic Validation
  3. Extending the use of tadalafil scaffold: Development of novel selective phosphodiesterase 5 inhibitors and histone deacetylase inhibitors

Extending the use of tadalafil scaffold: Development of novel selective phosphodiesterase 5 inhibitors and histone deacetylase inhibitors

  • Bioorg Chem. 2020 May;98:103742. doi: 10.1016/j.bioorg.2020.103742.
Ahmed K ElHady 1,  Shou-Ping Shih 2,  Yu-Cheng Chen 3,  Yi-Chang Liu 4,  Nermin S Ahmed 1,  Adam B Keeton 5,  Gary A Piazza 5,  Matthias Engel 6,  Ashraf H Abadi 1,  Mohammad Abdel-Halim 7
Affiliations

Affiliations

  • 1 Department of Pharmaceutical Chemistry, Faculty of Pharmacy and Biotechnology, German University in Cairo, Cairo 11835, Egypt.
  • 2 Doctoral Degree Program in Marine Biotechnology, National Sun Yat-sen University, 70 Lien-Hai Road, Kaohsiung 804, Taiwan; Doctoral Degree Program in Marine Biotechnology, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei 115, Taiwan.
  • 3 The Ph.D. Program for Cancer Biology and Drug Discovery, China Medical University and Academia Sinica, Taichung 40402, Taiwan.
  • 4 Division of Hematology-Oncology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan; Department of Internal Medicine, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan.
  • 5 Department of Oncologic Sciences and Pharmacology, Drug Discovery Research Center, Mitchell Cancer Institute, University of South Alabama, Mobile, AL 36608, USA.
  • 6 Pharmaceutical and Medicinal Chemistry, Saarland University, Campus C2.3, D-66123 Saarbrücken, Germany.
  • 7 Department of Pharmaceutical Chemistry, Faculty of Pharmacy and Biotechnology, German University in Cairo, Cairo 11835, Egypt. Electronic address: mohammad.abdel-halim@guc.edu.eg.
PMID: 32199305 DOI: 10.1016/j.bioorg.2020.103742
Abstract

Herein we present the synthesis and characterization of a novel chemical series of tadalafil analogues that display different pharmacological profiles. Compounds that have the 6R, 12aR configuration and terminal carboxylic acid group at the side chain arising from the piperazinedione nitrogen were potent PDE5 inhibitors, with compound 11 having almost equal potency to tadalafil and superior selectivity over PDE11, the most common off-target for tadalafil. Modifying the stereochemistry into 6S, 12aS configuration and adopting the hydroxamic acid moiety as a terminal group gave rise to compounds that only inhibited HDAC. Dual PDE5/HDAC inhibition could be achieved with compounds having 6R, 12aR configuration and hydroxamic acid moiety as a terminal group. The Anticancer activity of the synthesized compounds was evaluated against a diverse number of cell lines of different origin. The compounds elicited Anticancer activity against cell lines belonging to lymphoproliferative Cancer as well as solid tumors. Despite the previous reports suggesting Anticancer activity of PDE5 inhibitors, the growth inhibitory activity of the compounds seemed to be solely dependent on HDAC inhibition. Compound 26 (pan HDAC IC50 = 14 nM, PDE5 IC50 = 46 nM) displayed the most potent Anticancer activity in the present series and was shown to induce Apoptosis in Molt-4 cells. HDAC isoform selectivity testing for compound 26 showed that it is more selective for HDAC6 and 8 over HDAC1 by more than 20-fold.

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