Japanese researchers to test use of iPS cells for cancer treatment

TOKYO (The Japan News/ANN) – A team led by research institute RIKEN and Chiba University in Japan will begin clinical tests for the treatment of cancers found in the head and neck area, using special immune cells created from induced pluripotent stem (iPS) cells, The Yomiuri Shimbun has learned.

The researchers are expected to start the clinical tests as early as within this year, aiming to shrink cancer cells by improving immunity, sources said. It will be the first clinical test of cancer therapy using iPS cells in the nation, they said.

Cancers of the head and neck include those of the nose, mouth, throat and ears, and account for about five per cent of all types of cancer in the nation.

The research team is led by Deputy Director of the RIKEN Centre for Integrative Medical Sciences Haruhiko Koseki and a professor of head and neck oncology at Chiba University Yoshitaka Okamoto.

The therapy involves the team producing natural killer T (NKT) cells using iPS cells from healthy third parties. Then the NKT cells will be injected into a blood vessel leading to the patient’s cancer-affected area.

The planned clinical tests will be conducted on three patients who have relapsed and whom it is difficult to treat with surgery.

The researchers will inject NKT cells three times — 30 million NKT cells at first and then twice more with different numbers of cells — taking side effects into account.

They plan to spend two years investigating the efficacy and safety of the treatment. It is said that NKT cells can attack cancer cells and also activate other immune cells.

In a separate clinical test conducted earlier, Chiba University cultured NKT cells from a patient with cancer in the head and neck area then injected them back into the patient. In the test, the cancer cells shrunk by up to 30 per cent to 40 per cent with a single administration of the NKT cells, according to the researchers.

However, NKT cells only make up about 0.1 per cent of blood, and it takes time to culture them — thus the university found it difficult to repeatedly culture and administer the cells.

To address such problems, Koseki and other researchers focussed on iPS cells that can proliferate indefinitely.

They developed a method for collecting NKT cells from human blood, transforming them into iPS cells and creating a large number of such cells, before transforming them back into NKT cells again.

When the group injected the NKT cells into mice, the development of cancer was subdued, they said.

If no problems are found in the clinical test, the researchers will move onto the next stage to check the efficacy of the treatment. The group is also studying plans to use the method to treat lung cancer.

“There’s a report that NKT cells can possibly induce other immune cells that attack cancers. If [the treatment] works to extend survival periods, in addition to shrinking tumors, this could become an effective method,” said Keio University Professor Yutaka Kawakami, who heads the Japanese Association of Cancer Immunology.