Palladium(II)-Indenyl Complexes Bearing N-Heterocyclic Carbene (NHC) Ligands as Potent and Selective Metallodrugs toward High-Grade Serous Ovarian Cancer Models

J Med Chem. 2024 Aug 22;67(16):14414-14431. doi: 10.1021/acs.jmedchem.4c01203. Epub 2024 Aug 9.

Abstract

In this study, we synthesized novel Pd(II)-indenyl complexes using various N-heterocyclic carbene (NHC) ligands, including chelating NHC-picolyl, NHC-thioether, and diNHC ligands, and two monodentate NHCs. Transmetalation reactions between a Pd(II)-indenyl precursor and silver-NHC complexes were generally employed, except for chelating diNHC derivatives, which required direct reaction with bisimidazolium salts and potassium carbonate. Characterization included NMR, HRMS analysis, and single-crystal X-ray diffraction. In vitro on five ovarian cancer cell lines showed notable cytotoxicity, with IC50 values in the micro- and submicromolar range. Some compounds exhibited intriguing selectivity for cancer cells due to higher tumor cell uptake. Mechanistic studies revealed that monodentate NHCs induced mitochondrial damage while chelating ligands caused DNA damage. One chelating NHC-picolyl ligand showed promising cytotoxicity and selectivity in high-grade serous ovarian cancer models, supporting its consideration for preclinical study.

MeSH terms

  • Antineoplastic Agents* / chemical synthesis
  • Antineoplastic Agents* / chemistry
  • Antineoplastic Agents* / pharmacology
  • Cell Line, Tumor
  • Coordination Complexes / chemical synthesis
  • Coordination Complexes / chemistry
  • Coordination Complexes / pharmacology
  • Drug Screening Assays, Antitumor
  • Female
  • Heterocyclic Compounds* / chemistry
  • Heterocyclic Compounds* / pharmacology
  • Humans
  • Indenes / chemical synthesis
  • Indenes / chemistry
  • Indenes / pharmacology
  • Ligands
  • Methane* / analogs & derivatives
  • Methane* / chemistry
  • Methane* / pharmacology
  • Ovarian Neoplasms* / drug therapy
  • Ovarian Neoplasms* / pathology
  • Palladium* / chemistry
  • Structure-Activity Relationship

Substances

  • Palladium
  • Methane
  • carbene
  • Ligands
  • Antineoplastic Agents
  • Heterocyclic Compounds
  • Coordination Complexes
  • Indenes