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Implant Makes Cells Kill Cancer 植入技术攻杀肿瘤
A polymer device trains immune cells to shrink tumors
一聚合体装置训练免疫细胞攻杀肿瘤
One of cancer's cleverest tricks is its ability to hide from the immune system. A new approach to cancer treatment called immunotherapy could spare patients at least some of the grueling battery of chemotherapy treatments by retraining the body's own defenders--the cells of the immune system--to recognize and destroy tumors. Now researchers at Harvard University have developed a simple way to do this inside the body: a polymer implant attracts and trains immune-system cells to go after cancer.
肿瘤一大厉害在于它的免疫逃避。一种新的叫做免疫疗法的治疗方法使用重新训练机体的卫士---免疫细胞的机制来重新识别癌细胞并摧毁之,无需向传统的化疗那样饱受熬战之苦。如今哈佛大学的研究者们已经研究出一简单方法,那就是在我们的体内植入聚合体来吸收和训练免疫系统细胞去追逃癌细胞。
The experimental approach has shown great success in animal studies, increasing the survival rate of mice with a deadly melanoma from 0 to 90 percent. The implant could also be used to treat diseases of the immune system such as arthritis and diabetes, and, potentially, to train other kinds of cells, including stem cells used to repair damage to the body.动物实验很成功,可将老鼠高致命恶性黑素瘤生存率从0提高到90%。植入方法同样可以用来治疗类风湿关节炎和糖尿病,且有潜在训练诸如干细胞之内的其他机体细胞来达到修复机体损伤的能力。
The usual methods for cancer immunotherapy are complex and have had little success in clinical trials, says David Mooney, a professor of bioengineering at Harvard who leads the development of the implant. First, immune cells called dendritic cells are removed from a patient's body; then they're exposed to chemical activators and cancer-specific antigens. These cells are then injected back into the patient, where they should, in theory, travel to the lymph nodes and activate another group of cells called T cells, training them to attack a tumor. But dendritic cells are fragile, and while this approach has increased survival in mice, it hasn't caused tumors to shrink in clinical trials with humans.
领导这样技术开发的哈佛大学生物工程学教授David Mooney声称:通常的免疫疗法复杂且临床效果不好。首先将数突状细胞(一种免疫细胞)从机体取出,再将他们暴露在化学催化剂及癌细胞特性抗原之下,然后将他们重新输入到机体,理论上,这些重新输入到机体的树突状细胞应该能到到达淋巴结,并在淋巴结出作用于另一种免疫细胞-T细胞,并训练T细胞如何攻击癌细胞。但是树突状细胞很脆弱,虽然在老鼠身上能明显提高生存率,但在人类身上的临床实验却不见肿瘤的缩小。
"When you transplant the cells, virtually all of them die, and you have very little control over what they do when they're reimplanted," says Mooney. So his team took a different approach to the problem, realizing that "perhaps we could do all this inside the body."
Mooney说这是因为当你重新植入树突状细胞时,事实上其中大部分已经死亡,且很难控制到底重新输入的树突状细胞在机体干什么,基于此,他的团队采用另外方法来解决这个问题,也就是意识到或许可以在机体内完成这些。
Mooney and his research group constructed a polymer that can do inside the body what complex immunotherapies do outside it. They describe the design and performance of an implant for melanoma in the current issue of Nature Materials. The polymer has a history of safe use in humans (in biodegradable sutures, for example). First, it attracts dendritic cells by releasing a kind of chemical signal called a cytokine. Once the cells are there, they take up temporary residence inside spongelike holes within the polymer, allowing time for the cells to become highly active.
Mooney和他的研发团队构建了一聚合体,它能在体内完成传统免疫疗法在体外完成的工作。他们在Nature Material(自然材料)上阐述了针对黑素瘤的植入法设计性能。此聚合体在人类历史上曾安全使用过,比如能生物降解的医学缝合。此聚合体通过释放一种叫做cytokine(细胞浆)的物质来吸聚树突状细胞。一旦树突状细胞被吸聚过来,它们将在聚合体中的海绵状小孔内短暂驻留至强活性状态。
The polymer carries two signals that serve to activate dendritic cells. In addition to displaying cancer-specific antigens to train the dendritic cells, it is also covered with fragments of DNA, the sequence of which is typical of bacteria. When cells grab on to these fragments, they become highly activated. "This makes the cells think they're in the midst of infection," Mooney explains. "Frequently, the things you can do to cells are transient--especially in cancer, where tumors prevent the immune system from generating a strong response." This extra irritant was necessary to generate a strong response, the Harvard researchers found.
此聚合体载有2上信号来作用树突状细胞。其一是加载癌细胞特性抗原来训练树突状细胞。其二是典型细菌的DNA片段,当细胞接触到这些片段是将会高度活性。Mooney解释说,这是因为细胞会认为它们处于感染状态。在肿瘤逃避免疫机制中这类强烈反应状态很短暂,因此哈佛研究者们发现额外的刺激很必要拉加强细胞的强烈反应。
When implanted just under the skin of mice carrying a deadly form of melanoma, the polymer increased their survival rate to about 90 percent. By contrast, conventional immunotherapies that require treating the cells outside the body are 60 percent effective, says Mooney.
Mooney声称,当植入聚合体应用到老鼠黑素瘤时,生存率增至90%,而传统的体外免疫疗法仅仅60%有效。
[ 本帖最后由 hcs_usst 于 2009-2-3 09:58 编辑 ] |
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