Immune cells to target cancer created from stem cells

Immune cells that can recognise and kill cancer cells have
been grown from induced pluripotent stem cells (iPSCs). Although any clinical
application would likely be decades away, the achievement may provide the basis
for a future cell-based cancer therapy.

The study, published in the journal Cell Stem Cell, focused
on white blood cells called cytotoxic, or 'killer', T-cells. The
scientists, from the RIKEN Research Centre for Allergy and Immunology in Japan took
these killer T-cells, specialised against a type of cancer, and reprogrammed
them to produce iPSCs in the laboratory.

The iPSCs were then stimulated to produce many more killer
T-cells, specific for the same type of cancer. The work marks an important technical
breakthrough as cells produced in this way previously had had short life spans
and were therefore of limited use.

Killer T-cells recognise infectious or cancerous cells in
the body, according to the markers present on the surface of the cell. Having identified a foreign cell, they then
mount an attack to remove it. These
cells are present in the body normally but often in numbers too low to overcome
the cancer. It is hoped that boosting killer
T-cell numbers may tip the balance in the patient's favour.

Dr Hiroshi Kawamoto, who led the research said: 'This
strategy may solve the problem which the current immunotherapy strategies are
facing, and thus would make a major breakthrough in cancer therapy'.

But the research so far has only shown that these cells can
be made in the laboratory. It remains to
be seen whether they would be effective clinically.

Dr Emma Smith, senior science information officer at Cancer
Research UK, highlighted that the study 'was only carried out with cells in the
lab, and as the researchers haven’t shown that these reprogrammed T-cells can
actually kill cancer cells in animals or humans, more research is needed'.

Dr Kawamoto confirmed that the next step for his team would be 'to
test whether these T cells can selectively kill tumour cells but not other
cells in the body. If they do, these cells might be directly injected into
patients for therapy'.

Other leading researchers have welcomed the study. Professor Alan Clarke, director of the
European Cancer Stem Cell Research Institute at Cardiff University, told the
BBC: 'This
is a potentially very exciting development which extends our capacity to
develop novel cell therapies'.