A team of EU-funded scientists has come up with a potentially powerful cancer treatment that uses blue light to activate a platinum-based drug. As well as being more potent than other platinum-based medicines, the light-activated treatment could allow doctors to kill cancer cells in a more targeted way. The findings, by researchers in the UK, are published in the journal Angewandte Chemie.
EU support for the work came from the PHOTORUACD ('Novel photodissociable ruthenium-based anticancer drugs') project, a EUR 178,000 Marie Curie Intra-European Fellowship from the People Programme of the Seventh Framework Programme (FP7).
The precious metal platinum is already widely used in cancer treatments, for example in the drugs cisplatin, carboplatin and oxaliplatin. Activating a platinum-based drug with light ('photoactivation') would enable clinicians to selectively activate the drug within tumours. This would reduce damage to surrounding healthy tissue, avoid side effects and possibly extend the application of platinum drugs to cancer cells that have become drug resistant as well as to other cancer types.
Scientists at the University of Warwick have already succeeded in creating a platinum complex that is activated by ultraviolet A (UVA) light. However, this narrow wavelength would limit its use in the clinic, according to the researchers. In this latest study, the Warwick team, together with colleagues from Ninewells Hospital in Dundee and the University of Edinburgh, describe a novel platinum compound that is activated by low doses of visible blue or green light.
Furthermore, the complex, whose full name is trans,trans,trans-[Pt(N3)2(OH)2(py)2], is stable, easy to work with and water soluble, meaning it can dissolve and be flushed out of the body once used.
'The special thing about our complex is that it is not only activated by ultraviolet light, but also by low doses of blue or green light,' explains Peter Sadler of the Department of Chemistry at the University of Warwick, who led the research. 'Light activation generates a powerful cytotoxic compound that has proven to be significantly more effective than treatments such as cisplatin.'
The team suspect that their novel treatment could be particularly promising for the treatment of cancers and pre-cancerous conditions in thin-walled organs such as the bladder and oesophagus. Tests on oesophagus cancer cells grown in the laboratory showed that once activated by blue light, the compound is highly effective, and the team are now testing the compound's effectiveness on ovarian and liver cancer cells.
'This compound could have a significant impact on the effectiveness of future cancer treatments. Light activation provides this compound's massive toxic power and also allows treatment to be targeted much more accurately against cancer cells,' commented Professor Sadler.
'We believe that photoactivated platinum complexes will make it possible to treat cancers that have previously not reacted to chemotherapy with platinum complexes. Tumours that have developed resistance to conventional platinum drugs could respond to these complexes and with less side effects.' Source; European Union
(20min delay)