新型癌症靶向治疗载体

　　

生物通报道，来自ScienceDaily消息，北卡罗来大学的研究人员鉴定出一种新的植物病毒，有趣的是，该病毒可感染人类细胞，可用作治疗癌症的靶向载体。

 

据介绍，这种植物病毒的只有人类发丝宽度的1/1000那么大，专嗜人类某种细胞，对其他类型的细胞和组织没有侵害性。因此，研究人员希望能将这一病毒用于癌症靶向治疗中，将该植物病毒制备成药物载体。科研工作者称这一病毒为Nanoparticle Smart Bomb（纳米小炸弹，生物通注）。

 

参与此项研究项目的有化学专家Stefan Franzen教授，植物病理学家Steven Lommel教授，他们发现这一植物病毒只专一地侵蚀某种人类细胞，对其他细胞和组织无毒副作用，可作为癌症药物载体，辅助化学疗法，同时降低化学疗法的毒副作用。

 

作为载体，这一植物病毒具有无与伦比的优势，首先它能在植物体内进行大规模培养；其次病毒内部具有较大的携带外源物质的空间。研究人员称，只要适当的修饰这些病毒，比如说添加上信号肽，就能保证病毒与相匹配的人类细胞结合，达到靶向的作用。一旦病毒进入细胞内就能表达出携带在基因组上的外源蛋白，这些外源蛋白可以是治疗癌症的药物。

 

在质量控制方面，病毒的生物膜的开闭性受环境钙离子影响。科学家们利用这一优点来制备癌症药物载体。当病毒进入人体血液中时，由于血液中钙离子浓度高，病毒的生物膜关闭，药物无法释放出来。当病毒跟随信号肽进入匹配的细胞中时，由于细胞中钙离子浓度降低，病毒生物膜开启，抗癌药物也随之释放。由于病毒大学的问题，释放药物的速度缓慢足以达到缓释的效果。

 

这也许是下一代抗癌药物的最佳载体，科学家们对这一载体持乐观态度，他们相信这种治疗手段毒副作用小，更安全可靠。（生物通小茜）

生物通推荐原文检索：Nanoparticle 'Smart Bomb' Targets Drug Delivery To Cancer Cells

Researchers at North Carolina State University have successfully modified a common plant virus to deliver drugs only to specific cells inside the human body, without affecting surrounding tissue. These tiny "smart bombs" - each one thousands of times smaller than the width of a human hair - could lead to more effective chemotherapy treatments with greatly reduced, or even eliminated, side effects.

 

Drs. Stefan Franzen, professor of chemistry, and Steven Lommel, professor of plant pathology and genetics, collaborated on the project, utilizing the special properties of a fairly common and non-toxic plant virus as a means to convey drugs to the target cells.

 

The researchers say that the virus is appealing in both its ability to survive outside of a plant host and its built-in "cargo space" of 17 nanometers, which can be used to carry chemotherapy drugs directly to tumor cells. The researchers deploy the virus by attaching small proteins, called signal peptides, to its exterior that cause the virus to "seek out" particular cells, such as cancer cells. Those same signal peptides serve as "passwords" that allow the virus to enter the cancer cell, where it releases its cargo.

 

"We had tried a number of different nanoparticles as cell-targeting vectors," Franzen says. "The plant virus is superior in terms of stability, ease of manufacture, ability to target cells and ability to carry therapeutic cargo."

 

Calcium is the key to keeping the virus' cargo enclosed. When the virus is in the bloodstream, calcium is also abundant. Inside individual cells, however, calcium levels are much lower, which allows the virus to open, delivering the cancer drugs only to the targeted cells.

 

"Another factor that makes the virus unique is the toughness of its shell," Lommel says. "When the virus is in a closed state, nothing will leak out of the interior, and when it does open, it opens slowly, which means that the virus has time to enter the cell nucleus before deploying its cargo, which increases the drug's efficacy."

 

The researchers believe that their method will alleviate the side effects of common chemotherapy treatments, while maximizing the effectiveness of the treatment.