推荐活动

PNAS:揭示体内促进癌症生长和扩散新机制

首页 » 1970-01-01 转化医学网 赞(2)
分享: 
导读
<p align="center"><img src="http://www.bioon.com/biology/UploadFiles/201207/2012071123541453.jpg" alt="" width="400" height="349" border=&quo...
<p align="center"><img src="http://www.bioon.com/biology/UploadFiles/201207/2012071123541453.jpg" alt="" width="400" height="349" border="0" /></p>
在一项新研究中,研究人员发现一种之前未知的促进癌症生长和扩散的机制。这一机制涉及发挥关键作用的免疫细胞和被称作microRNA的小调节性分子的新功能。这一发现指出一种治疗癌症和可能治疗免疫系统疾病的新策略。

<!--more-->

来自美国俄亥俄州立大学综合性癌症中心和洛杉矶儿童医院的研究人员发现,肿瘤细胞释放的小泡(tiny vesicle)经健康的免疫细胞摄取后,导致免疫细胞排出促进肿瘤细胞生长和扩散的化学物质。

这项研究利用肺癌细胞作为研究对象并证实这些小泡含有发挥强大调节作用的分子microRNA,免疫细胞摄取这些分子之后行为发生改变。在人体内的这一过程涉及一种基础性的被称作Toll样受体8(Toll-like receptor 8, TLR8)的免疫系统受体。2012年7月2日,相关研究成果发表在<em>PNAS</em>期刊上。

研究通讯作者、俄亥俄州立大学人类癌症遗传学项目主任Carlo Croce博士说,“这项研究揭示出microRNA的一种新作用:它能够结合到一种蛋白受体上。这就告诉我们一些与癌症相关联的microRNAs能够以一种类似激素的方式结合和激活一种受体,在此之前,人们从没有观察到这种现象。”

microRNAs有助于控制细胞表达的蛋白类型和数量,而且通常是通过结合到表达蛋白的mRNA上来实现的。

研究第一作者Muller Fabbri博士说,“在这项研究中,我们发现癌症利用一种完全新的机制来生长和扩散,因而我们能够开发出新药物来对抗肿瘤。”

Fabbri说,“同样令人兴奋的是,我们证实这种机制涉及一种基础性的免疫系统受体TLR8,这意味着这一发现可能对诸如自身免疫疾病和炎症性疾病之类的其他疾病治疗产生影响。”

这项研究的关键性发现如下所示:

(1)肺肿瘤细胞释放被称作胞外体(exosome)的小泡,这些小泡含有microRNA-21和microRNA-29a。位于在正常组织与肿瘤组织相毗邻之处的免疫细胞---巨噬细胞---摄取这些胞外体。
(3)就人巨噬细胞而言,microRNA-21和microRNA-29a与TLR8相结合,导致巨噬细胞分泌出肿瘤坏死因子α(tumor-necrosis-factor alpha, TNFα)和白细胞介素6(interleukin-6, IL-6),而这两种细胞因子促进炎症产生。
(3)这两种细胞因子水平的增加与模式动物肺中肿瘤数量增加相关联,因为这两种细胞因子水平的下降会导致肺中肿瘤数量减少,这就意味着它们在肿瘤转移中也发挥着作用。

本文译自<a href="http://medicalxpress.com/news/2012-07-reveals-mechanism-cancer-growth-body.html" target="_blank">Study reveals new mechanism that might promote cancer's growth and spread in the body</a>
<div id="ztload">
<div>
<div>

<img src="http://www.bioon.com/biology/UploadFiles/201202/2012021422295002.gif" alt="" width="113" height="149" border="0" />

<a title="" href="http://dx.doi.org/10.1073/pnas.1209414109" target="_blank">doi:10.1073/pnas.1209414109</a>
PMC:
PMID:

</div>
<div>

<br/><strong>MicroRNAs bind to Toll-like receptors to induce prometastatic inflammatory response</strong><br/>


Muller Fabbria,1,2,3, Alessio Paonea,2, Federica Calorea,2, Roberta Gallia, Eugenio Gaudioa, Ramasamy Santhanama, Francesca Lovata, Paolo Faddaa, Charlene Maoa, Gerard J. Nuovob, Nicola Zanesia, Melissa Crawfordc, Gulcin H. Ozera, Dorothee Wernickea, Hansjuerg Aldera, Michael A. Caligiurid, Patrick Nana-Sinkamc, Danilo Perrottia, and Carlo M. Crocea,3

MicroRNAs (miRNAs) are small noncoding RNAs, 19–24 nucleotides in length, that regulate gene expression and are expressed aberrantly in most types of cancer. MiRNAs also have been detected in the blood of cancer patients and can serve as circulating biomarkers. It has been shown that secreted miRNAs within exosomes can be transferred from cell to cell and can regulate gene expression in the receiving cells by canonical binding to their target messenger RNAs. Here we show that tumor-secreted miR-21 and miR-29a also can function by another mechanism, by binding as ligands to receptors of the Toll-like receptor (TLR) family, murine TLR7 and human TLR8, in immune cells, triggering a TLR-mediated prometastatic inflammatory response that ultimately may lead to tumor growth and metastasis. Thus, by acting as paracrine agonists of TLRs, secreted miRNAs are key regulators of the tumor microenvironment. This mechanism of action of miRNAs is implicated in tumor–immune system communication and is important in tumor growth and spread, thus representing a possible target for cancer treatment.

</div>
</div>
</div>
评论:
评 论
共有 0 条评论

    还没有人评论,赶快抢个沙发

相关阅读