S'pore discovery opens door to engineered cells as cancer cure

SINGAPORE - Could engineered human stem cells hold the key to a cancer cure?

A recent discovery by Singapore scientists from the Institute of Bioengineering and Nanotechnology (IBN) - a research body under the Agency for Science, Technology and Research (A*STAR) - proves that science fiction may be not too far off from reality.

The team, led by lead researcher Dr Shu Wang, have discovered certain cells have the innate ability to target tumour cells outside the central nervous system.

These neural stem cells (NSCs) were derived using human induced pluripotent stem (iPS) cells. Pluripotent stem cells can give rise to any fetal or adult cell type.

The NSCs were then loaded with a suicide gene and injected into mice with breast cancer.

The study found that the cells then homed in on the breast tumors in the mice, and also accumulated in various organs infiltrated by the cancer cells such as the lung, stomach and bone.

A drug to activate the suicide gene to kill the cancerous cells upon contact was then injected into the mice. Subsequent follow up revealed that the test mice survived for a significantly longer time, from 34 days to 39 days.

"We have demonstrated that tumor-targeting neural stem cells may be derived from human iPS cells, and that these cells may be used in combination with a therapeutic gene to cripple tumor growth," said Dr Wang, adding that the team will continue to improve the method to prevent and minimise unwanted side effects.

The discovery promises an alternative to conventional cancer treatment, said Professor Jackie. Y. Ying, IBN Executive Director.

In addition, IBN's approach of using iPS cells to derive NSCs is less laborious and suitable for large-scale manufacture of uniform batches of cellular products. It will also help eliminate variability in the quality of the cellular products, A*STAR said.

Furthermore, since iPS cells are developed from a patient's own cells, the likelihood of immune rejection would be reduced.

On an ethical note, these iPS cell-derived NSCs are derived from adult cells, which bypasses the sensitive ethical issue surrounding the use of human embryos.

The effectiveness of using NSCs to treat brain tumors has been investigated in previous studies.

However, this is the first study that demonstrates that NSCs could also target tumors outside the central nervous system to treat both primary and secondary tumors.

Cancer remains a leading cause of death worldwide, accounting for 7.6 million deaths in 2008, and breast cancer is one of the most common causes of cancer deaths each year.

In Singapore, more than 1,400 women are diagnosed with breast cancer and more than 300 die as a result of breast cancer each year.

The high fatality rate of cancer is partially attributed to the invasive ability of malignant tumors to spread throughout the human body, and the ineffectiveness of conventional therapies to eradicate the cancer cells.