Team at Riken taps iPS cells to kill cancer


Japanese researchers said Friday they succeeded in efficiently regenerating T cells capable of destroying melanoma from induced pluripotent stem cells, an achievement that could make cell-based anticancer therapy more powerful.

The current cancer immunotherapy tries to stimulate the immune systems of patients to increase T cells, a type of lymphocyte, in their bodies. But its effects are limited because T cells do not increase dramatically.

The researchers, headed by Hiroshi Kawamoto of the national research institute Riken, said their newly developed iPS-based method is efficient enough to mass produce T cells with specific functions.

T cells have millions of variants with unique receptors, depending on their genetic configurations. T cells react to other cells by using the receptors on their surface. One type, cytotoxic T lymphocyte, is known to attack viruses and cancer cells.

According to the Riken-led team’s article published in the U.S. journal Cell Stem Cell, the group established iPS cells, which are premature cells that can develop into any type of tissue, from mature cytotoxic T cells specific for the melanoma epitope and differentiated the iPS cells into cells with a T cell receptor specific for the epitope. After stimulating the differentiated cells with an immunosuppressive antibody, the team saw a large number of cells specific for the original epitope generated.

A different team led by Hiromitsu Nakauchi, professor at the University of Tokyo, also reported in the same journal that it has reprogrammed clonally expanded T cells from an AIDS patient into iPS cells and regenerated HIV-killing cells from the pluripotent cells.