Blue light fires up cancer drug

U. WARWICK (UK) —A platinum-based compound activated by visible blue light is 80 times more powerful than other platinum-based anticancer drugs, according to new research.

Using light activation, the compound also appears able to kill cancer cells in a much more targeted way than similar treatments. The research is published in Angewandte Chemie.

Scientists had already found a platinum-based compound that they could activate with ultra-violet light but that narrow wave length of light would have limited its use. The new compound—known as trans,trans,trans-[Pt(N3)2(OH)2(py)2]—can be activated by normal visible blue, or even green, light.

It is also stable and easy to work with, and it is water soluble so it can simply dissolve and be flushed out of the body after use.

“This compound could have a significant impact on the effectiveness of future cancer treatments,” says Peter Sadler, professor of chemistry at the University of Warwick.

“Light activation provides this compound’s massive toxic power and also allows treatment to be targeted much more accurately against cancer cells.”

Sadler passed the new compound to colleagues at Ninewells Hospital Dundee, who tested it on oesophageal cancer cells cultivated within lab equipment.

Those tests show that once activated by blue light the compound was highly effective requiring a concentration of just 8.4 micro moles per liter to kill 50 percent of the cancer cells.

The researchers are also beginning to examine the compound’s effectiveness against ovarian and liver cancer cells. Early results there are also excellent but that testing work is not yet complete.

“The special thing about our complex is that it is not only activated by ultra-violet light, but also by low doses of blue or green light,” Sadler says.

“Light activation generates a powerful cytotoxic compound that has proven to be significantly more effective than treatments such as cisplatin.

“We believe that photoactivated platinum complexes will make it possible to treat cancers that have previously not reacted to chemotherapy with platinum complexes. Tumors that have developed resistance to conventional platinum drugs could respond to these complexes and with less side-effects.”

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