快猫短视频

THE next generation of cancer-killing viruses may be able to kill even those tumour cells that spread throughout the body.

Frank McCormick of the University of California, San Francisco, and his team pioneered the idea of destroying cancer cells with adenoviruses, relatives of those that cause the common cold. Viruses kill cells by hijacking their machinery to make copies of themselves.

But to replicate, an adenovirus must first inactivate 鈥済uardian鈥� proteins such as p53. McCormick realised that a mutant virus without the ability to knock out p53 wouldn鈥檛 be able to replicate inside normal cells. But it would reproduce in cancer cells that lack p53鈥攁s many do. The trick works. One cancer-killing virus, called ONYX-015, is doing well in trials where the virus is injected directly into tumours (快猫短视频, 5 August 2000, p 19).

Now McCormick and colleagues at Onyx Pharmaceuticals in California have developed an improved version of the virus called ONYX-411. Much like its predecessor, ONYX-411 will only replicate in cells that lack a guardian protein, in this case one called pRb that almost all cancer cells lack. But as an extra safety measure, the virus is engineered so it cannot even switch on its genes unless a tumour-specific protein is present. In tests on human cancer cells, ONYX-411 has proved to be even better at destroying the tumour cells than its forebear, and seems to trigger almost no adverse reactions.

That suggests that you might be able to inject ONYX-411 into the bloodstream to treat tumours that have spread through the body, says Thomas Dubensky at Cerus of California. 鈥淥NYX-015 has shown itself to be safe and very effective.鈥� But there might be even better viruses in the pipeline, he adds.