A cheap, off-the-shelf DNA analysis technique used by forensic scientists could save medical researchers millions of dollars in wasted research and prevent them making career-destroying mistakes, says a UK company.
Recent investigations have revealed that thousands of cell lines identified as being from a particular tumour, organ or animal are contaminated with other cells, or simply incorrectly labelled.
Up to one third of the cell lines in use today are not what scientists believe them to be, making costly and time-consuming research invalid, says Colin Arlett of the MRC Cell Mutation Unit at Sussex University, UK.
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Paul Debenham of LGC, a DNA-analysis company in Teddington, UK, in collaboration with an international team of researchers, has used a technique called STR profiling to analyse over 200 cell lines. This technique involves examining seven tiny stretches of DNA from a sample. The result is a simple numerical identification code, unique to a cell line sample.
Researchers around the world could use the technique to check that the numerical code produced by profiling their sample matches a standard reference code held on a central database.
鈥溈烀ǘ淌悠祍 have bemoaned the fact that there hasn鈥檛 been a simple test that they all can use,鈥� Debenham says. 鈥淯sing this test seems so self-evidently sensible, all researchers should adopt it.鈥�
Stephen O鈥橞rien of the US National Cancer Institute in Frederick, Maryland, US, agrees. 鈥淭his represents the most advanced and powerful forensic technique to dispense with the embarrassing and expensive cell contamination that occurs in the biomedical laboratories,鈥� he writes in a commentary on the new work in the journal Proceedings of the National Academy of Sciences.
Highly variable
STR profiling is used to identify DNA samples held in the UK鈥檚 national DNA database. 鈥淭his technique is commercially available, and widely used in forensic science,鈥� says Debenham. 鈥淲e鈥檙e simply saying that it also meets the need for cell line work.鈥�
Just seven of the Short Tandem Repeat (STR) sequences that are common in the human genome are used to generate a profile. There is high variability in these stretches of DNA, making the sequences ideal targets for distinguishing between two or more DNA samples, says the research team.
Debenham analysed 253 cell lines, including some known to be contaminated with other cells, and found that the technique can reliably be used to uniquely identify a particular line.
There have been other approaches to using DNA analysis to identify cell lines, such as DNA fingerprinting. But these have been technically complicated, expensive and over-sensitive, says O鈥橞rien. 鈥淭he cell biologist should welcome a cheap verifiable technology to avoid these costly mistakes,鈥� he says. 鈥淭his report goes a long way in this direction.鈥�
Where the central database of identifying reference codes would be held is not clear, Debenham says. But there are research authorities in the US and Europe that could set up freely accessible databases on the internet, he suggests.
Debenham thinks journal editors should also require the submission of the STR profile codes along with submitted research.
More at: Proceedings of the National Academy of Sciences (Early edition, vol 2, no 25)