Johns Hopkins大学的科学家最近发明了一种治疗直肠结肠癌的新方法，他们利用小型分子将放射试剂输送到癌细胞内，而不像目前的方法一样是利用结合到细胞表面来从外部攻击癌细胞，这会造成有害副作用。
在实验室中针对正常细胞和癌细胞进行的实验中，新的放射试剂输送系统被证明能特定攻击肠癌细胞，而剩余的物质能很容易的被肾脏滤出，因为输送系统的分子非常小。
在10月3日的在线版PLoS one上，Hopkins的肠癌专家John Abraham和Stephen Meltzer博士利用小分子能获得更好的疗效的想法，设计了只有10个氨基酸长度的小型蛋白质，并将其作为他们药物的基础。与此相比，携带放疗或化疗试剂的抗体能超过1000个氨基酸长度。
小组在分子上结合了放射性磷P32，以测试他们的多肽能有多好的效果，结果Abraham表示：“令人惊讶的是，第一项测试就显示细胞能吞入这些分子，从而将放疗剂送入细胞内，并通过破坏DNA和蛋白质来杀死癌细胞。”
科学家同时警告这种新型放疗剂输送系统还不能用于人类，但Abraham注意到P32能发出极高能量，并穿透5毫米厚的人体组织，这意味着它是治疗肠癌的很好试剂，因为肠癌常常会形成大而厚的组织，药物无法很好穿透。除此之外P32结合的多肽还有一个用处：在肿瘤还很小时发现肠癌的转移和复发。这些多肽能反应出漂移的癌细胞所处位置。
随后Abraham、Meltzer以及他们的小组设计了多种P32-多肽，并在18份正常或癌变人类细胞样本中进行了测试。其中最有效的多肽MA5能和腺癌细胞结合，腺癌构成了肠癌的95％，这比其它细胞类型强150倍，并能在2小时内进入到细胞内。（教育部科技发展中心）
原文链接：http://www.physorg.com/news111162280.html
原始出处：
Received: July 11, 2007; Accepted: September 12, 2007; Published: October 3, 2007
Novel Decapeptides that Bind Avidly and Deliver Radioisotope to Colon Cancer Cells
John M. Abraham1*, Fumiaki Sato1, Yulan Cheng1, Bogdan Paun1, Takatsugu Kan1, Alexandru Olaru1, Zhe Jin1, Jian Yang1, Rachana Agarwal1, Stefan David1, James P. Hamilton1, Tetsuo Ito1, Yuriko Mori1, Stephen J. Meltzer1,2
1 Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America, 2 Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
Abstract
Background
The rapidly growing field of targeted tumor therapy often utilizes an antibody, sometimes tagged with a tumor-ablating material such as radioisotope, directed against a specific molecule.
Methodology/Principal Findings
This report describes the discovery of nine novel decapeptides which can be radioactively labeled, bind to, and deliver 32P to colon cancer cells. The decapeptides vary from one another by one to three amino acids and demonstrate vastly different binding abilities. The most avidly binding decapeptide can permanently deliver very high levels of radioisotope to the adenocarcinoma cancer cell lines at an efficiency 35 to 150 times greater than to a variety of other cell types, including cell lines derived from other types of cancer or from normal tissue.
Conclusions/Significance
This experimental approach represents a new example of a strategy, termed peptide binding therapy, for the potential treatment of colorectal and other adenocarcinomas.
全文链接：http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0000964
