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IridiumIII Luminescent Probe for Detection of the Malarial Protein Biomarker Histidine Rich Protein-II
Published on: July 7, 2015
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Mitochondria-targeted spin-labelled luminescent iridium anticancer complexes.
V Venkatesh1,2, Raul Berrocal-Martin3, Christopher J Wedge4
1Department of Chemistry , University of Warwick , Coventry CV4 7AL , UK .
Chemical Science
|March 24, 2018
Summary
New iridium(iii) complexes targeting mitochondria show potent anticancer activity. The complex with two TEMPO labels (Ir-TEMPO2) demonstrated superior antiproliferative and antioxidant effects, especially against prostate cancer cells.
Area of Science:
- Inorganic Chemistry
- Medicinal Chemistry
- Cancer Biology
Background:
- Mitochondrial dysfunction is a hallmark of cancer.
- Targeting mitochondrial metabolism offers a promising therapeutic strategy.
- Cyclometallated iridium(iii) complexes are explored for their potential in cancer treatment.
Purpose of the Study:
- To design and synthesize novel cyclometallated iridium(iii) complexes with TEMPO spin labels.
- To investigate the photophysical properties and mitochondrial localization of these complexes.
- To evaluate their antiproliferative and antioxidant activities against various cancer cell lines.
Main Methods:
- Synthesis of iridium(iii) complexes with one (Ir-TEMPO1) and two (Ir-TEMPO2) TEMPO spin labels.
- Electron paramagnetic resonance (EPR) spectroscopy to study spin-spin interactions.
- Luminescence spectroscopy to determine lifetimes and decay kinetics.
- Density functional theory (DFT) calculations for conformational analysis.
- In vitro antiproliferative assays (IC50 determination) and antioxidant activity assays.
- Confocal microscopy for cellular localization studies.
Main Results:
- Ir-TEMPO2 exhibited spin-spin interactions between TEMPO units, unlike Ir-TEMPO1.
- Both complexes displayed luminescence with long lifetimes; Ir-TEMPO2 showed biexponential decay, indicating conformational flexibility.
- Ir-TEMPO2 demonstrated significantly higher antiproliferative activity than Ir-TEMPO1 across cancer cell lines.
- Ir-TEMPO2 possessed superior antioxidant activity against ovarian cancer cells.
- Ir-TEMPO2 was highly potent against PC3 prostate cancer cells (IC50 = 0.53 microM), outperforming cisplatin and showing enhanced selectivity.
- Both complexes were localized in the mitochondria of cancer cells.
Conclusions:
- The presence of two TEMPO labels in Ir-TEMPO2 enhances its anticancer efficacy and antioxidant properties.
- Ir-TEMPO2 represents a highly potent and selective mitochondria-targeting agent for prostate cancer therapy.
- These iridium(iii)-TEMPO complexes hold significant promise for developing novel cancer therapeutics.
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