Photostable Platinated Bacteriochlorins as Potent Photodynamic Agents

J Med Chem. 2021 May 27;64(10):6792-6801. doi: 10.1021/acs.jmedchem.1c00052. Epub 2021 May 14.

Abstract

Photodynamic therapy (PDT) is used to treat various cancerous diseases. Recently, we have demonstrated that platinated pyridyl-substituted porphyrins are potent agents for PDT with very high phototoxicity (IC50 down to 17 nM) and excellent phototoxic indices of higher than 5800 (p.i. = IC50(dark)/IC50(light)) [Rubbiani, R. et al., Chem. Commun. 2020, 56, 14373]. However, the absorption of porphyrins is not ideal for the treatment of larger tumors because they essentially do not absorb light between 650 and 850 nm. Herein, we report stable conjugates of a novel bacteriochlorin with cisplatin and transplatin. They exhibit extremely high phototoxicity (IC50 values down to 6 nM, irradiated with a 750 nm LED at a fluence of 5 J/cm2), very low dark toxicity, and thereby extremely high phototoxic indices up to 8300. Based on these exciting results, we believe that platinated bacteriochlorins are promising candidates for further investigation as novel PDT anticancer agents.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line, Tumor
  • Cell Nucleus / metabolism
  • Cell Survival / drug effects
  • Cisplatin / chemistry*
  • Crystallography, X-Ray
  • Drug Resistance, Neoplasm / drug effects
  • Humans
  • Light
  • Microscopy, Fluorescence
  • Molecular Conformation
  • Photosensitizing Agents / chemistry*
  • Photosensitizing Agents / metabolism
  • Photosensitizing Agents / pharmacology
  • Porphyrins / chemistry*
  • Reactive Oxygen Species / metabolism

Substances

  • Photosensitizing Agents
  • Porphyrins
  • Reactive Oxygen Species
  • bacteriochlorin
  • transplatin
  • Cisplatin