原标题：MIT利用载药系统二次释放药物治疗癌症

    2014年5月22日讯 /生物谷BIOON/ --最近MIT的科学家在Science Signaling上发表了一项最新研究成果。他们利用脂质体实现了两种药物的包载和分别释放，并进而达到了很好的治疗效果。根据这项研究的负责人Paula Hammond和Michael Yaffe介绍说，他们首先构建了一个标记有叶酸的脂质体，使其能够靶向肿瘤细胞，同时将能够缓解癌症症状的药物erlotinib连接到脂质体表面，将抗肿瘤药物阿霉素包载到脂质体内部共同运输到病灶部位。研究结果显示，erlotinib和阿霉素会先后释放到肿瘤部位，其释放峰值时间间隔相差24小时。这种释放方式保证了药物的二次高峰，更有利于杀灭肿瘤细胞。进一步的小鼠研究表明，这种疗法对肺癌和乳腺癌的疗效明显。研究人员表示这种方法有很大的发展空间。（生物谷Bioon.com）

    详细英文报道：

Scientists at MIT have engineered a one-two punch for cancer that carries two drugs at a time and has been shown to shrink lung and breast tumors in mice. While other nanoparticles have carried multiple drugs, this one makes use of a specific timing mechanism to get the most out of each treatment.

In a study from 2012, the researchers found that a regimen involving a pretreatment of the cancer-weakening drug erlotinib and then a dose of the cancer-killing doxorubicin was more effective than delivering both at the same time.

Now lead researchers Paula Hammond and Michael Yaffe have published new findings in the journal Science Signaling, demonstrating that the treatment was effective in mice, shrinking triple-negative breast tumors and non-small-cell lung tumors significantly, according to a report from MIT.

To make this treatment work, the team created liposomes that carry doxorubicin on the inside and erlotinib on the outside. Tagged with folate, they target the tumor cells and start to break down, first releasing the erlotinib and then the doxorubicin. Most importantly, the nanoparticle allows for a lag time of about 24 hours between the peak doses of the drugs, giving them a true one-two punch.

"I think it's a harbinger of what nanomedicine can do for us in the future," Hammond said in a statement. "We're moving from the simplest model of the nanoparticle--just getting the drug in there and targeting it--to having smart nanoparticles that deliver drug combinations in the way that you need to really attack the tumor."

Yaffe added: "It's like rewiring a circuit. … When you give the first drug, the wires' connections get switched around so that the second drug works in a much more effective way."