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'.