KYOTO--A Japanese research team’s new technique to produce induced pluripotent stem (iPS) cells with an enhanced ability to attack tumors has proven effective in experiments and could help improve cancer survival rates.

The researchers created iPS cells from cells of the immune system known as cytotoxic T cells that identify and attack cancer cells. Then they turned the engineered iPS cells back into T cells.

Normal T cells are found in the body in small numbers and have a short lifespan, but the iPS cell-derived T cells had an enhanced ability to attack tumors and proliferated 10,000-fold in eight weeks.

Using the method, Hiroshi Kawamoto, an immunology professor at Kyoto University’s Institute for Frontier Life and Medical Sciences, and his colleagues succeeded in treating mice with cancer cells.

The researchers confirmed through an in-vitro experiment that those rejuvenated T cells attacked and reduced cancer cells from leukemia patients.

They also injected the iPS cell-based T cells into 15 mice with transplanted leukemia cells and found that four of them were still alive after five months. In contrast, 15 untreated mice all died within two months.

“The new technology is expected to prove effective as well when combined with Opdivo, a new anticancer drug that activates immune cells, and other drugs,” said Kawamoto.

The findings were published in the U.S. medical journal Cancer Research on Nov. 22.