Apoptosis induced by 2-aryl benzothiazoles-mediated photodynamic therapy in melanomas via mitochondrial dysfunction

Chem Res Toxicol. 2014 Jul 21;27(7):1187-98. doi: 10.1021/tx500080w. Epub 2014 Jun 13.


A mild and efficient synthetic development of 2-arylbenzothiazoles 5 mediated by ceric ammonium nitrate (CAN) via intramolecular cyclization of N-phenyl-thiobenzamides 4 was achieved. Further compounds 5 were reduced to corresponding amines 6, and their photodynamic therapy (PDT) effect was evaluated on malignant human melanoma A375 cells. Amine 6l plus ultraviolet A (UVA) induced caspase-3 activity, poly(ADP-ribose)polymerase cleavage, M30 positive CytoDeath staining, and subsequent apoptotic cell death. Our data disclosed that treatment of A375 cells with 6l plus UVA resulted in a decrease in mitochondrial membrane potential (ΔΨmt), oxidative phosphorylation system (OXPHOS) subunits, and adenosine triphosphate (ATP) but an increase in mitochondrial DNA 4977-bp deletion via reactive oxygen species (ROS) generation. Transmission electron microscopy (TEM) observations also showed major ultrastructural alterations of mitochondria. Additionally, 6l plus UVA was also shown to reduce murine melanoma size in a mouse model. The present study supports the hypothesis that 6l-PDT may serve as a potential ancillary modality for the treatment of melanoma.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis / drug effects
  • Benzothiazoles / pharmacology*
  • Benzothiazoles / radiation effects
  • Benzothiazoles / therapeutic use
  • Cell Line, Tumor
  • Cell Survival / drug effects
  • Cytochromes c / metabolism
  • Female
  • Humans
  • Melanoma, Experimental / drug therapy
  • Melanoma, Experimental / metabolism*
  • Melanoma, Experimental / pathology
  • Membrane Potential, Mitochondrial / drug effects
  • Mice, Inbred ICR
  • Mitochondria / drug effects*
  • Mitochondria / physiology
  • Photochemotherapy*
  • Photosensitizing Agents / pharmacology*
  • Photosensitizing Agents / therapeutic use
  • Reactive Oxygen Species / metabolism
  • Skin Neoplasms / drug therapy
  • Skin Neoplasms / metabolism*
  • Skin Neoplasms / pathology
  • Tumor Burden / drug effects
  • Ultraviolet Rays


  • Benzothiazoles
  • Photosensitizing Agents
  • Reactive Oxygen Species
  • Cytochromes c