Stem cells take root in drug development

Stem cells have assumed near-mythical status in the popular imagination as a possible cure for every disease under the sun. But while public attention has focused on their potential in regenerative medicine, stem cells have quietly gained a foothold in drug development a move that may hail a huge but unheralded shake-up of the biological sciences.

I think there are tremendous parallels to the early days of recombinant DNA in this field, says James Thomson, director of regenerative biology at the Morgridge Institute for Research in Madison, Wisconsin, and one of the founders of Cellular Dynamics International, also in Madison. I dont think people appreciated what a broad-ranging tool recombinant DNA was in the middle '70s." At the same time, he says, they underestimated the difficulty of using it in treatments.

Now stem cells are in a similar situation, he says, and although therapeutic use is likely to come to fruition eventually, people underappreciate how broadly enabling a research tool it is, he says.

Laboratory-grown stem cells hold much promise for regenerative medicine, but are being increasingly used in drug testing.

MASSIMO BREGA, THE LIGHTHOUSE/SCIENCE PHOTO LIBRARY

Drug companies began dipping a tentative toe into the stem-cell waters about two years ago (see 'Testing time for stem cells'). Now, the pharmaceutical industry is increasingly adopting stem cells for testing the toxicity of drugs and identifying potential new therapies, say those in the field.

Cellular Dynamics sells human heart cells called cardiomyocytes, which are derived from induced pluripotent stem (iPS) cells. Thomson says that essentially all the major pharma companies have bought some. The company also produces brain cells and cells that line blood vessels, and is about to release a line of human liver cells.

Yet Cellular Dynamics is just one of the companies in the field. Three years ago, stem-cell biologist Stephen Minger left his job in UK academia to head GE Healthcares push into stem cells (see 'Top scientist's industry move heralds stem-cell shift'). The medical-technology company, headquartered in Chalfont St. Giles, UK, has been selling human heart cells made from embryonic stem (ES) cells for well over a year, and is due to start selling liver cells soon.

Minger and his team at GE Healthcare assessed the heart cells in a blind trial against a set of unnamed drug compounds to see if the cells would reveal which compounds were toxic. When the compounds were unmasked, Minger says, they found that the cells had been affected by the known toxic compounds. But, crucially, in a number of cases, the cells identified a problem that had only been discovered after the drugs had reached the market and after they had been approved by agencies such as the US Food and Drug Administration (FDA).

These are compounds which went all the way through animal testing, then went through phase I, II, III and then were licensed in many cases by the FDA, says Minger.

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Stem cells take root in drug development