文章想投《Nature》？先给细胞验明正身

　　

生物通报道，最新一期的《Nature》发表了一篇以Identity crisis为题的社论文章，发表了对一株细胞系污染事件的看法，据悉该细胞系是40年前建立的一株细胞系，40年前并未发现细胞系已遭污染，时至今日，遭污染的细胞系已经进入上千家实验室，并且多家实验室发表的论文所使用的就是这一细胞系。

 

现在这株遭污染和错误鉴定身份的细胞系已经被多个生物学研究者使用，这一事件的关注度也逐步攀升。现在，使用这一污染的细胞系的研究者都需要对目前实验室所使用的细胞系进行鉴定，鉴定这一细胞系其实很简单，用常规的廉价的DNA测序就能完成鉴定。

 

据悉，数千生物实验室的研究者都在实验这株细胞系，很多人都不知道该细胞系在传至第五或是第三代的时候已经不是他们原先认为的细胞系了。在过去的25年，已经传播至多国（美国，英国，德国，日本）的细胞系被发现18%-36%的培养物含有另外一种细胞类型，这证实这一细胞系已经被其他的细胞污染。

 

细胞系遭污染，那么对科学研究的影响有多大？社论文章称，这要取决于实验项目的类型。比如说，细胞系被用作生化药剂来源，混入其中的另外一种细胞则是无害的。但是，如果用这个细胞系来研究某一组织的特性则可能出现重大的失误，因为混入了另外一种细胞，其研究的结果将与事实不符，尤其是研究癌症或是其他疾病影响更大。

 

值得关注的是，很多已经发表的文章中使用的是这一遭污染的细胞系。

 

就连管理严格的美国国家癌症研究所的细胞库都出现了细胞系遭污染的事情。现在实验室研究人员唯一的办法是给细胞验明正身，使用DNA指纹图谱分析技术验证您所使用的细胞是否与数据库的数据一致以鉴定身份。

 

Nature杂志社希望这一身份鉴定工作能持续下去，将主要的无限制增殖的细胞系（癌细胞）鉴定完毕，在未来，Nature杂志可能要求投稿人为文章中的所有细胞系提供身份验证。（生物通 小茜）

 

 Invitrogen公司为您准备了细胞培养技术资料点击索取

 

获得更多详情：http://www.nature.com/nature/journal/v457/n7232/full/457935b.html

 

Editorial

Nature 457, 935-936 (19 February 2009) | doi:10.1038/457935b; Published online 18 February 2009

Identity crisis

Abstract

It is time for all involved to tackle the chronic scandal of cell-line contamination. Funders first.

 

Some 40 years after it was first recognized, the use of contaminated and misidentified cell lines in biological research remains a growing problem. But it is a problem that has a simple solution: routine, cheap, DNA profiling of laboratory cultures. It is now time to implement that solution. To do so, scientists need the funding and motivation to verify the cell lines in their possession, as well as a curated electronic database of authenticated DNA profiles against which they can compare their results.

 

Thousands of biology labs use cell lines, yet many do not know that between a fifth and a third of the lines in common use may not be what they seem. In the past 25 years, numerous studies, as well as the experience of cell-culture repositories in the United States, Britain, Germany and Japan, have found that 18–36% of cultures contain a misidentified species or cell type. The effect of using such cells varies depending on the project involved. When the lines are used as a source of biochemicals, for example, the misidentified lines are innocuous. Deployed in the study of a general cellular process, they can have minor drawbacks. But on the rare occasions that the cell lines are thought to reflect the properties of a particular tissue, cancer or disease state, the outcome can be severely damaging as funding and research get driven into work based on false premises.

 

To make matters worse, papers are still published that contain unwarranted conclusions derived from misidentified lines. It is ironic that many researchers who are obsessed with using only the highest-quality chemicals and biologics from the most trusted suppliers don't think twice about using cell lines known to be misidentified.

 

Repositories need to authenticate all of their cell lines, and the major funders must direct support accordingly.

 

Cell repositories do carry out quality-control assays on deposited lines, although the tests performed vary. Even a venerated panel of 60 tumour lines at the US National Cancer Institute was found to have some that were either HeLa (the first human cancer cell line) or subcultures of one another.

 

This crisis of identification can be solved by analysing repository cell lines using DNA fingerprinting — short tandem repeat (STR) assays — and making the 'authenticated' profiles available in a database. Some of the cell-line profiles in the American Type Culture Collection, for example, already have their STR profiles listed. The German DSMZ cell repository performs DNA profiles for every line, but has also reported that 29% of its human tumour line deposits are cross-contaminated. It costs between $20 and $400 to fingerprint a cell sample (depending on country and circumstance), and some predict that the $2 STR analysis is not far away. At that price, what lab could not afford to regularly recheck its cultures?

 

In an open letter in 2007, Roland Nardone of the Discovery Center for Cell and Molecular Biology in Washington DC, and his colleagues brought the issue of misidentification to the attention of Michael Leavitt, until recently director of the US Department of Health and Human Services. This moved the issue forward: by the end of the year the National Institutes of Health (NIH) formally recognized in a public notice that "misidentification of cell cultures is a serious problem". However, the notice went on to state that "it would be impractical for the NIH to require application of particular methods in all grant applications", and put the onus on peer reviewers to quality-control their colleagues' research proposals and manuscripts.

 

This merely capitulates to the status quo. Four decades after the problem came to light, it is time for this cavalier attitude to be jettisoned. Repositories need to authenticate all of their lines, and the NIH and other major funders must direct support accordingly. The STR profiles should be lodged in a global database that provides tools for readily comparing a culture's fingerprint with authenticated profiles. The funders should motivate investigators by encouraging the inclusion in grant proposals of expense estimates for cell-line verification, in recognition that this quality assurance will increase the costs of research. The community, in turn, should accept that it makes sense to verify cell lines routinely.

 

Once this research framework is sufficiently established, major funders will be able to require the validation of all immortal cell lines in order for investigators to retain funding, and journals should (and Nature will) require that all lines used in a paper were verified before publication.