A group of researchers including a Japanese scientist in Britain have succeeded in producing induced pluripotent stem (iPS) cells without using a virus, therefore significantly reducing the risk of cancer, it was learned Sunday.
Production efficiency with the technique is about 25 times greater than the common method using viral vectors, according to sources.
The achievement, expected to boost safety in regenerative medicine, will be released in the online version of Science, a British scientific journal.
Keisuke Kaji, who heads the group of researchers from the University of Edinburgh, and those from University of Toronto and other institutions, said they combined four types of versatility-inducing genes into one group, sandwiched them with a specific DNA configuration and injected them into human skin cells with a specific enzyme.
As a result, the four genes were grouped into chromosomes, having produced iPS cells, the researchers said.
Usually, iPS cells are produced by implanting three to four types of genes into retroviral vectors and introducing them into somatic cells.
This method, however, carries the risk of damaging chromosomes and causing cancer in the cells.
As a result, researchers worldwide have been studying ways to produce iPS cells without using viral vectors.
Kyoto University Prof. Shinya Yamanaka has succeeded in producing iPS cells using mice.
The researchers also succeeded in separating the four genes by introducing the specific enzyme into the mice's iPS cells, returning the positioning of the chromosomes to their original condition, they said.
"Because we succeeded in recovering the chromosomes, the risk of cancer [in the iPS cells] was significantly reduced. It'll also be possible to remove the four chromosomes in human iPS cells," Kaji said.