Impostor cells are wrecking medical research

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Impostor cells are wrecking medical research

17:26 19 September 03 Exclusive from New Scientist Print Edition. Subscribe and

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Countless research projects around the world into cancer and other major

diseases are producing bogus or misleading results because investigators are

studying the wrong type of cell.

 

The mistakes arise when fast-growing " rogue cells " contaminate cell cultures and

swamp the correct cells. A team's work on prostate cancer, for example, might

turn out to be worthless because cells researchers thought were prostate cancer

cells turn out to be cervical cancer cells.

 

Although the danger has been known about for decades, most researchers still

fail to check the identity of the cells they are working with. And several new

types of rogue cell are emerging, New Scientist has learned.

 

Warnings of the potential scale of the problem were issued this week at a

conference in Warwick organised by the UK's Health Protection Agency. Precise

figures are hard to come by because researchers are either unaware that they

have worked with the wrong cells, or try to cover it up.

 

" If people have spent three years working on the wrong cells, they are not

likely to want to tell people about it, " says David Lewis, manager of the

European Collection of Cell Cultures, based at Porton Down in Wiltshire. He will

emphasise the importance of getting cells from authenticated sources at this

week's conference.

 

 

Rogue cells

 

 

The best estimates available suggest around a fifth of all experiments in fields

such as cancer and microbiology involve the wrong cells. " Various figures

between 20 and 40 per cent have been aired, " says Rod MacLeod, head of the

genetics laboratory at the DSMZ, the German collection of cell cultures in

Braunschweig.

 

In a study in 1999, MacLeod found that of 252 cancer cell lines, 18 per cent

were " impostors " . And newly established cell lines were just as likely to be

contaminated as older ones. He blames this on the ease with which cell lines can

be contaminated.

 

The most notorious rogue cells are so-called " HeLa " cells. They rapidly overrun

more sluggish colonies.

 

" Just one HeLa cell could survive and proliferate, " MacLeod says. Attempts to

purge cell lines contaminated by HeLa cells have waxed and waned since 1967,

when the problem first emerged, but now there are new rogue cells to deal with

too.

 

 

Bladder cancer

 

 

One posing particular problems in cancer research is the T24 line of bladder

cancer cells. MacLeod and Hans Drexler, director of the human and animal cell

collection at the DSMZ, discovered them in 2002 " posing " as healthy epithelial

cells that line organs.

 

They are now popping up all over the place, especially in cultures of other

cancer cells. Recently they contaminated prostate cancer cell lines, as Adrie

van Bokhoven of the University of Colorado Health Sciences Center in Denver

discovered. " Two years after our research, there are still publications that

describe it as prostate, " van Bokhoven says.

 

In a review to be published in November 2003 in The Prostate journal, van

Bokhoven will highlight the problems posed by another rogue cell, an unusually

lively prostate cancer cell line called PC-3.

 

" We reveal that another three 'unique' prostate lines were actually PC-3, " he

says, adding to others he has already discovered.

 

 

Denial syndrome

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Before journals publish a paper van Bokhoven wants editors to insist that

researchers provide proof that their cell lines are authentic. " Editors should

demand it, " says van Bokhoven, who points out that the DNA fingerprinting tools

now available should allow the problem to be eradicated. " There are no more

excuses, " he says.

 

John Masters of University College London, who has struggled for years to

highlight the problem, agrees. " I've written to journal editors till I'm blue in

the face on this, and they do nothing, " he says. This unwillingness to confront

the issue has been dubbed " false cell-line denial syndrome " by Drexler, who says

that the problem will persist as long as it is swept under the carpet.

 

Senior figures at the American Type Culture Collection have also tried for years

to highlight the problem, says Keith Bostian, of the American Society of

Microbiology. The ASM is aware of the problem, he says, and its journals

" encourage " authors to deposit cell lines in public collections for

authentication.

 

Yet one survey conducted by the ATCC revealed that two-thirds of journals still

fail to cite the source of biological materials. Worse, many of the cultures the

ATCC receives for deposit are misidentified or contaminated.

 

Andy Coghlan

 

 

 

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