[Cu(o-phthalate)(phenanthroline)] Exhibits Unique Superoxide-Mediated NCI-60 Chemotherapeutic Action through Genomic DNA Damage and Mitochondrial Dysfunction.
The in cellulo catalytic production of reactive oxygen species (ROS) by copper(II) and iron(II) complexes is now recognized as a major mechanistic model in the design of effective cytotoxins of human cancer. The developmental complex, [Cu(o-phthalate)(1,10-phenanthroline)] (Cu-Ph), was recently reported as an intracellular ROS-active cytotoxic agent that induces double strand breaks in the genome of human cancer cells. In this work, we report the broad-spectrum action of Cu-Ph within the National Cancer Institute's (NCI) Developmental Therapeutics Program (DTP), 60 human cancer cell line screen. The activity profile is compared to established clinical agents-via the COMPARE algorithm-and reveals a novel mode of action to existing metal-based therapeutics. In this study, we identify the mechanistic activity of Cu-Ph through a series of molecular biological studies that are compared directly to the clinical DNA intercalator and topoisomerase II poison doxorubicin. The presence of ROS-specific scavengers was employed for in vitro and intracellular evaluation of prevailing radical species responsible for DNA oxidation with superoxide identified as playing a critical role in this mechanism. The ROS targeting properties of Cu-Ph on mitochondrial membrane potential were investigated, which showed that it had comparable activity to the uncoupling ionophore, carbonyl cyanide m-chlorophenyl hydrazine. The induction and origins of apoptotic activation were probed through detection of Annexin V and the activation of initiator (8,9) and executioner caspases (3/7) and were structurally visualized using confocal microscopy. Results here confirm a unique radical-induced mechanistic profile with intracellular hallmarks of damage to both genomic DNA and mitochondria.
School of Chemical Sciences and National Institute for Cellular Biotechnology, Dublin City University , Glasnevin, Dublin 9, Ireland.
Creina
C
Slator
School of Chemical Sciences and National Institute for Cellular Biotechnology, Dublin City University , Glasnevin, Dublin 9, Ireland.
Niall
N
Barron
School of Biological Sciences & Focas Research Institute, Dublin Institute of Technology , Camden Row, Dublin 8, Ireland.
Orla
O
Howe
School of Chemical Sciences and National Institute for Cellular Biotechnology, Dublin City University , Glasnevin, Dublin 9, Ireland.
Andrew
A
Kellett
D000970:Antineoplastic Agents / Q000737:chemistry / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D045744:Cell Line, Tumor; D004249:DNA Damage / Q000187:drug effects*; D006801:Humans; D018613:Microscopy, Confocal; D008928:Mitochondria / Q000187:drug effects*; D015394:Molecular Structure; D010618:Phenanthrolines / Q000737:chemistry / Q000494:pharmacology*; D017382:Reactive Oxygen Species
D000970:Antineoplastic Agents; D010618:Phenanthrolines; D017382:Reactive Oxygen Species