RNAi技术在癌症研究领域取得突破性发现

　　

Thermo Fisher Scientific的RNAi技术在癌症研究领域取得突破性发现
      －Dharmacon全基因组siRNA文库实现对影响化疗药物效果的基因鉴定

WALTHAM, Mass., April 17, 2007 报道—当今世界服务科学的领导者，Thermo Fisher Scientific 公司 (NYSE: TMO) 今日宣布：德克萨斯大学西南医学中心运用Dharmacon的RNA干扰技术取得了一项突破性发现（Dharmacon现为Thermo Scientific品牌的一员）。德克萨斯大学西南医学中心的细胞生物学教授，迈克尔.怀特博士和他的研究团队鉴定出87个可以影响人肿瘤细胞在一定的化疗药物刺激下变得更加敏感的基因。
RNA干扰（RNAi）是一种基于双链RNA分子可以通过碱基互补配对原则而降解目标靶基因信使RNA（mRNA），从而达到沉默靶基因表达水平的基因调节方式。怀特博士使用Dharmacon全人类基因组siARRAY®文库中的SMARTpool siRNA试剂，这种试剂靶向全人类基因组超过21,000条单独的基因，来沉默分离的人肺癌细胞特定基因的表达。结果发现当某些基因被沉默后，化疗药物紫杉醇（paclitaxel ，也称Taxol）对肿瘤细胞的杀伤力变得更加有效。怀特博士的此项研究成果发表在4月12日的Nature杂志上。

这一发现将有助于以怀特博士团队所鉴定基因的蛋白为靶标的新一代药物的研发，并提升当前癌症治疗的效果。最终结果将形成一种能降低化疗药物剂量并减轻副作用的新的联合治疗方式。

“我们非常荣幸将Dharmacon独有的、高效的全基因组siRNA试剂提供给怀特博士和他的研究团队”，Thermo Fisher Scientific公司生物科学领域的技术与商业发展副总经理威廉 S 马歇尔博士如是说，“怀特博士发表于Nature的开创性工作是对当今成熟尖端技术应用于热点医学问题的一大榜样。”

Dharmacon的siARRAY文库之所以能帮助怀特博士有如此的重大发现，是因为此种试剂可以帮助科学家快速的检测某种特定基因被沉默后对细胞的影响。这种高通量技术，采用了在RNAi机制种的活性媒介物siRNA得以实现。怀特博士和他的研究团队通过使用人类全基因组siRNA试剂处理non-small-cell lung cancer cells，然后检测在化疗药物紫杉醇有无情况下细胞的活力水平。他们发现当分别抑制其中的87个不同的基因时，将导致肿瘤细胞对紫杉醇有高出10,000倍的敏感性。后续的研究将进一步确定在临床前研究和临床研究中抑制这些基因是否也有同样的效果。

“在人类细胞能做到这一点，并能快速的完成我们所需要的，证明这种研究工具异常强大，”怀特博士说，“进行如此规模的检测其目的是感受这种新一代技术在沉默我们所需基因的优越性，这种全基因检测的强大动力在于：你在没有任何的期望中进行实验，一切由科学数据告诉你什么是重要的。我们对Dharmacon高效卓越的siRNA试剂持有深刻的印象，这也是我们能够如此大规模检测成功的关键！”

德克萨斯大学西南医学中心是RNAi全球倡议（组织）的一员，RNAi全球倡议（组织）由Thermo Fisher Scientific公司的RNA技术产品团队创立。其成员由20多个分布于北美、欧洲和亚洲的非盈利性著名的生物化学研究机构组成。此倡议（组织）提供一个论坛，供给各个成员分享研究技术、建立实验标准以及通过交换和比较检测数据从而进行深入机理研究。德克萨斯大学西南医学中心是第一个使用Dharmacon的人类全基因组siRNA文库发表研究的机构。

“怀特博士是RANi全球倡议（组织）的创办成员，也是第一个接受全基因组siRNA试剂进行研究的科学家，”迈克尔说，“建立这个倡议（组织）的目标是将基于RNAi的全基因组检测技术的强大工具和全球的领先研究所合作，从而加速在生物学和医学中的研究进程。怀特博士是我们努力的首创者！”

*附怀特博士发表于4月12日Nature杂志的文章摘要信息和本报道英文原文：
怀特博士发表于4月12日Nature杂志的文章摘要信息如下：
Letter
Nature 446, 815-819 (12 April 2007) | doi: 10.1038/nature05697; Received 26 October 2006; Accepted 20 February 2007
Synthetic lethal screen identification of chemosensitizer loci in cancer cells
Angelique W. Whitehurst1, Brian O. Bodemann1, Jessica Cardenas1, Deborah Ferguson2, Luc Girard3, Michael Peyton3, John D. Minna3,4, Carolyn Michnoff5, Weihua Hao5, Michael G. Roth5, Xian-Jin Xie4,6 & Michael A. White1,4
1. Department of Cell Biology,
2. Reata Pharmaceuticals,
3. Hamon Center for Therapeutic Oncology Research,
4. Simmons Cancer Center,
5. Department of Biochemistry, and,
6. Center for Biostatistics and Clinical Science, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
Correspondence to: Michael A. White1,4 Correspondence and requests for materials should be addressed to M.A.W. (Email: [e-mail]).
Abundant evidence suggests that a unifying principle governing the molecular pathology of cancer is the co-dependent aberrant regulation of core machinery driving proliferation and suppressing apoptosis. Anomalous proteins engaged in support of this tumorigenic regulatory environment most probably represent optimal intervention targets in a heterogeneous population of cancer cells. The advent of RNA-mediated interference (RNAi)-based functional genomics provides the opportunity to derive unbiased comprehensive collections of validated gene targets supporting critical biological systems outside the framework of preconceived notions of mechanistic relationships. We have combined a high-throughput cell-based one-well/one-gene screening platform with a genome-wide synthetic library of chemically synthesized small interfering RNAs for systematic interrogation of the molecular underpinnings of cancer cell chemoresponsiveness. NCI-H1155, a human non-small-cell lung cancer line, was employed in a paclitaxel-dependent synthetic lethal screen designed to identify gene targets that specifically reduce cell viability in the presence of otherwise sublethal concentrations of paclitaxel. Using a stringent objective statistical algorithm to reduce false discovery rates below 5%, we isolated a panel of 87 genes that represent major focal points of the autonomous response of cancer cells to the abrogation of microtubule dynamics. Here we show that several of these targets sensitize lung cancer cells to paclitaxel concentrations 1,000-fold lower than otherwise required for a significant response, and we identify mechanistic relationships between cancer-associated aberrant gene expression programmes and the basic cellular machinery required for robust mitotic progression.

 

本报道英文原文如下：
Thermo Fisher Scientific RNA Technology Enables Groundbreaking Discovery in Cancer Research
Dharmacon Genome-wide siRNA Library Helps Identify Genes that Impact Effectiveness of Chemotherapy Drug
WALTHAM, Mass., April 17, 2007 — Thermo Fisher Scientific Inc. (NYSE: TMO), the world leader in serving science, today announced that the University of Texas Southwestern Medical Center has made a groundbreaking discovery using the company’s Dharmacon RNA-interference reagents, marketed under the Thermo Scientific brand. Dr. Michael White, professor of cell biology at UT Southwestern, and his team have identified 87 genes that appear to affect the susceptibility of human cancer cells to certain chemotherapy drug treatments.
RNA interference (RNAi) is a mechanism of gene regulation in which double-stranded RNA can “silence” a gene by eliminating the messenger RNA (mRNA) corresponding to that gene. Dr. White used the Dharmacon siARRAY® Whole Human-Genome collection of SMARTpool small-interfering RNA molecules, which target the entire human genome of more than 21,000 individual genes, to block the action of specific genes in isolated lung cancer cells. He found that when certain genes were silenced, the chemotherapy drug paclitaxel (Taxol) was dramatically more effective in destroying the cancer cells. Dr. White’s study appears in the April 12 edition of the leading science journal, Nature.
This discovery could lead to the development of new drugs that target the protein products of the genes identified by Dr. White’s team and enhance the effectiveness of current cancer therapies. The eventual result could be new combination therapies that lower the dose of chemotherapy, reducing its debilitating side effects.
“We are very pleased to have provided Dr. White and his team with our unique genome-wide collection of highly effective siRNAs,” said William S. Marshall, Ph.D., vice president of technology and business development for biosciences at Thermo Fisher Scientific. “Dr. White’s seminal work reported in Nature is an example of paradigm-shifting technology applied to a significant medical problem.”
The Dharmacon siARRAY library enabled Dr. White’s discovery because it allows scientists to quickly test how cells react when specific genes are silenced. This high-throughput technique employs small-interfering RNA (siRNA), the active intermediate in the RNAi mechanism. Dr. White and his team treated human non-small-cell lung cancer cells with siRNAs targeting each gene in the human genome and monitored survival in the presence or absence of the drug paclitaxel. They identified 87 different genes that, when inhibited, caused the cancer cells to be up to 10,000 times more sensitive to paclitaxel. Additional research will be needed to determine whether blocking the genes in pre-clinical and clinical studies has the same effect.
“Being able to do this in human cells – and being able to do it fast – is very powerful,” Dr. White said. “The idea of the screen was to take advantage of new-generation technology to silence any gene we want. That’s the power of a genome-wide screen – you go in without any expectations and let the data tell you what’s important. We were very impressed by the potency and robustness of the Dharmacon siRNA collection, which is vital in enabling such large-scale screening efforts.”
The University of Texas Southwestern Medical Center is a member of the RNAi Global Initiative founded by the RNA Technologies product team within Thermo Fisher Scientific. An alliance comprising 20 renowned not-for-profit biomedical research institutions from North America, Europe and Asia, the initiative provides a forum for members to share research protocols, establish experimental standards and develop mechanisms for exchanging and comparing screening data. UT Southwestern is the first institution to publish a human genome-wide study using the Dharmacon siRNA library.
“Dr. White is a founding member of the RNAi Global Initiative and the first to receive the whole genome siRNA collection,” said Marshall. “Our goal in establishing the initiative was to combine the power of genome-wide RNAi-based screening with the collaboration of leading research institutions to accelerate biological and medical discovery. Dr. White has been a leader in our efforts.”