Cancer-killing cells work well in mice

Human stem cells have been reprogrammed to form cancer-targeting immune cells that were shown to stop tumour growth in mice.

Scientists generated induced pluripotent stem cells (iPS cells) from white blood cells known as T-lymphocytes, then reprogrammed these to become cancer-specific T-cells that were able to multiply into large numbers in the laboratory.

Immunotherapy — where immune cells are taken from the blood, multiplied and injected back into the body — shows promise as a treatment for cancer. However, finding enough T-cells, immune cells that can kill cancer cells while ignoring healthy ones, is rare, particularly in people whose immune system is already low as a result of cancer. This approach could mean that unlimited numbers of T-cells could be produced in the laboratory and targeted at a specific type of tumour.

The researchers, from the Memorial Sloan-Kettering Cancer Centre, USA, wrote: 'In summary, the combination of... technologies that we describe here offers a potential new source of off-the-shelf T-cells of pre-determined antigen specificity'.

The study makes use of two techniques — generating iPS cells in the lab and converting these to form T-cells, and then genetically modifying them to target cancer cells, known as chimeric antigen receptor (CAR) technology.

'By combining the CAR technology with the iPS technology, we can make T cells that recognise X, Y, or Z', Dr Michel Sadelain, who led the study, told The Scientist. 'There's flexibility here for redirecting their specificity towards anything that you want'.

The T lymphocytes are directed towards CD19, a protein generated by malignant cells. When tested in mice with lymphoma, the T-cells were seen to 'potently inhibit tumour growth', said the study.

'This is very specific to the cancer cells themselves. This means fewer side effects and secondly, because they stay in the body, they are 'living drugs' and once present move around and stop recurrences', Dr Sadelain told the Express.

'It looks pretty exciting. It's effectively using the body's own immune system and harnessing its power to attack the cancer cells', Dr Emma Smith, senior science information officer at Cancer Research UK, told the Express.

The study was published in Nature.