澳门金沙网上娱乐平台:Hope revives for divide and die cancer drugs

时间:2019-03-07 03:07:01166网络整理admin

By Jonathan Knight DRUGS that stop cells maintaining their chromosomes may after all help treat cancer in humans—provided they are not used alone. Biologists have found that such drugs are much more effective against human cancer cells than earlier experiments with mice suggested. Cancer cells need the enzyme telomerase to stop the ends of chromosomes, called telomeres, from shortening with each cell division. This led drugs researchers to look at telomerase inhibitors as a potential cancer treatment. However, mice that lack the enzyme survive for generations and even develop tumours, suggesting that chromosome ends degrade too slowly for telomerase inhibitors to be effective. “I don’t think that’s a good argument for them not working in humans,” says Jerry Shay at the University of Texas Southwestern Medical Center in Dallas. He points out that human telomeres are shorter than those in mice and so should disappear sooner in a dividing cell deprived of telomerase. Shay and his colleagues treated cancerous breast and prostate tumour cells with short antisense RNA molecules designed to block telomerase. With each cell division, the telomeres in both types of cell shrank, and after 120 days all the breast cells had died. Some prostate cells survived due to their slightly longer telomeres, Shay says. Because it takes so long for the cells to die, Shay sees telomerase inhibitors being used to complement other therapies, rather than as a sole weapon against primary tumours. “With chemotherapy and surgery, most people survive their initial cancers,” he says. “It’s cancer relapse that kills.” Shay believes that blocking telomerase might kill any rogue cells before they establish a new tumour. The researchers also found that telomeres grow back in cells that survive the treatment. This means normal cells that need telomerase, like the stem cells that maintain the gut, might recover from an attack by telomerase inhibitors,