Seeing red will be the signal to attack

日期:2019-03-08 06:08:14 作者:子车芜掉 阅读:

By Michael Day A CHEMOTHERAPY drug has been tweaked by chemists so that it is activated only by light. This could enable doctors to target the toxic cancer treatment directly at tumours, leaving healthy tissues unscathed. The drug is cisplatin, an important treatment for testicular and ovarian cancers. It binds to DNA in tumour cells, preventing the genetic code from giving its orders and disrupting cell division. But the drug also affects DNA in other rapidly dividing cells, so it is highly toxic to healthy tissues. Ordinary cisplatin contains platinum in the form Pt(II), which makes ionic bonds with two chloride ions. The new cisplatin molecule, developed by Peter Sadler of Edinburgh University, contains Pt(IV), which makes four ionic bonds, two with iodide ions instead of chloride. Pt(IV) can’t bind to DNA, so it can’t disrupt cell division. But when exposed to blue laser light, it reverts to the active form Pt(II) that is able to latch onto DNA. So by giving a patient the new drug and then illuminating tumour cells with lasers, it should be possible to kill tumours without damaging other tissues (Angewandte Chemie International Edition, vol 38, p 1460). “The idea is to get compounds that aren’t toxic on their own but can be activated in selected cells,” says Sadler. Pharmacologists at Greifswald University in Germany have already shown that the new treatment can kill cancer cells in the test tube. Human trials are “some way down the line”, says Sadler. He hopes to alter the compound so that it is activated by red light,