CSIRO develops test to improve stem cell safety

CSIRO scientists have developed a test to identify unsafe stem cells. It is the first safety test specifically for human induced pluripotent stem cells (iPS) – as published today in the international journal Stem Cells.

  • 4 June 2013

The breakthrough is a significant step in improving the quality of iPS cells and identifying unwanted cells that can form tumours. The test also determines how stable iPS cells are when grown in the lab.

"The test we have developed allows us to easily identify unsafe iPS cells. Ensuring the safety of these cell lines is paramount and we hope this test will become a routine screen as part of developing safe and effective iPS-based cell therapies."

Dr Andrew Laslett, Research Group Leader – Stem Cells, CSIRO Materials Science and Engineering

Dr Andrew Laslett and his team have spent the last five years working on the project. The research has focused on comparing different types of iPS cells with human embryonic stem cells. iPS cells are now the most commonly used pluripotent stem cell type for research.

"The test we have developed allows us to easily identify unsafe iPS cells. Ensuring the safety of these cell lines is paramount and we hope this test will become a routine screen as part of developing safe and effective iPS-based cell therapies," says Dr Laslett.

Using their test method, Dr Laslett's team has shown that certain ways of making iPS cells carry more risks. When the standard technique is used, which relies on viruses to permanently change the DNA of a cell, unwanted tumours are more likely to form. In comparison, cells made using methods which do not alter cell DNA, do not form tumours.

Dr Laslett hopes the study and the new test method will help to raise the awareness and importance of stem cell safety and lead to improvements in quality control globally.

"It is widely accepted that iPS cells made using viruses should not be used for human treatment, but they can also be used in research to understand diseases and identify new drugs. Having the assurance of safe and stable cells in all situations should be a priority," says Dr Laslett.

The test uses laser technology to identify proteins found on the surface of the cells. Based on the presence or absence of specific proteins the cells are then separated and monitored. Unsafe stem cell lines are easily identified because they form recognisable clusters of cells and the safe ones don't. This test could also be applied to assess the safety of the recently announced somatic cell nuclear transfer human embryonic stem cells.

Professor Martin Pera, Program Leader of Stem Cells Australia, said: "Although cell transplantation therapies based on iPS cells are being fast-tracked for testing in humans, there is still much debate in the scientific community over the potential hazards of this new technology."

"This important study provides a simple and powerful technique for assessing how safe stem cell lines are for use in patients," he adds.

The paper, titled 'Identification of unsafe human induced pluripotent stem cell lines using a robust surrogate assay for pluripotency' is available on the Stem Cells website.

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Carlos Polanco J, Ho MSH, Wang B, Zhou Q, Wolvetang E, Mason E, Wells CA, Kolle G, Grimmond SM, Bertoncello I, O'Brien C, Laslett AL. 2013. Identification of Unsafe Human Induced Pluripotent Stem Cell Lines Using a Robust Surrogate Assay for Pluripotency [external link]. Stem Cells. 1549-4918. DOI: 10.1002/stem.1425.

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Dr Andrew Laslett, CSIRO stem cell expert, on stem cell safety
Dr Laslett talks about the test to improve stem cell safety.

Transcript

[A close up shot of Dr Andrew Laslett, CSIRO Stem Cell Expert appears on screen]

Dr Andrew Laslett: Using technology developed at CSIRO we've been able to show that we can identify unsafe IPS cells.  That's important because IPS cells have a real potential for being used in drug discovery and for potentially being used in cell therapy to treat a range of human diseases and injuries.

[Image changes to show to people in a laboratory type setting, one person is viewing something through a microscope]

So the test shows that some IPS cell lines made using viruses actually are able to re-form stem cells.

[Camera zooms in on the person on the microscope as he changes the slide that he's viewing]

Now this is a real danger in and we've shown that when we put these cells into animals that they are capable of forming tumours known as teratomas.So what this test shows is that these cell lines made using viruses are both unstable and unsafe for human use.

[Image has changed back to Dr Andrew Laslett]

One of the other reasons this study is important is because IPS technology is just starting to make the switch from a research to a potential clinical application.

[Image changes to show a lady handling different samples]

And as such there are regulations that cover cell therapy in general but there's no real safety tests available that are specific for IPS cells or induced very potent stem cells.

[Image changes to show a computer screen with different graphs on the screen]

[Image has changed back to Dr Andrew Laslett]

What we hope the publication of this test will do is to show people that not all stem cells are safe, we need to be really careful when we're thinking about putting cells made from stem cells into people. And there's also a large number of quasi legal stem cell companies in multiple countries around the world that are using stem cells to treat people.

People need to be very careful about that because our test shows that the easiest and simplest ways to make stem cells known as IPS cells is in fact quite dangerous for human health.

An FAQ and a video on iPS stem cells can be accessed on the Stem Cell Australia website [external link].