Poster Presentation 29th Lorne Cancer Conference 2017

Targeting copper homeostasis in glioblastoma using a chemically modified polyphenol (#106)

Aria M Ahmed-Cox 1 2 3 , Miriam B Brandl 2 3 , Giuseppe Cirillo 4 , Kathleen Kimpton 2 3 , Maria Kavallaris 2 3 , Orazio Vittorio 2 3
  1. School of Biotechnology and Biomolecular Sciences, UNSW, Sydney, NSW, Australia
  2. Children's Cancer Institute, Randwick, NSW, Australia
  3. Australian Centre for NanoMedicine and ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, UNSW, Sydney, NSW, Australia
  4. Department of Pharmacy Health and Nutritional Science, University of Calabria, Arcavacata di Rende, Italy

Background: Glioblastoma is the most aggressive and lethal tumour of the central nervous system, with a disproportional five year survival estimate of less than 3%. Given the difficulties of designing drugs capable of crossing the blood-brain barrier (BBB), and additional evidence of resistance to first line therapies, there is a clear need for the development of alternate treatments which overcome resistance mechanisms and selectively target cancer cells to reduce collateral toxicity. Recent investigations have highlighted the role of copper in supporting tumourigenesis, with elevated levels of copper found in a number of tumour types. In this study we used Dextran-Catechin (DC), a conjugated form of the polyphenol catechin with increased serum stability and proven anti-cancer activity, to target copper homeostasis in glioblastoma cells.

Material and Methods: Two different glioblastoma cell lines, U87 and T98G, were used in this study. Anticancer activity was tested by drug treated cell viability assays. Real time PCR and western blotting were used for gene and protein expression respectively. Intracellular metal ion content was measured by spectrophotometric analysis. Induction of oxidative stress was measured using a fluorescence assay, while the cellular level of the antioxidant glutathione (GSH) was examined by colorimetric assay.

Results: U87 and T98G were sensitive to DC with IC50 concentrations of 72 and 92 μg / mL respectively, with no significant effect on viability in non-malignant cells (MRC-5). Glioblastoma cells had an elevated copper content compared to normal MRC-5, which was shown to react with DC to generate reactive oxygen species and induce apoptosis. This was confirmed by a significant decrease of GSH levels and PARP cleavage.

Conclusion: Overall our data shows that the modified natural compound Dextran-Catechin is able to target copper homeostasis in glioblastoma and has the potential as an alternate treatment strategy for this disease.