WASHINGTON, July 26 (Xinhua) -- U.S. researchers said Wednesday that they had developed a new stem cell-based therapy that turns to distinctively stiff cancerous tissue to selectively target and kill metastatic tumors.
In a study appearing in the U.S. journal Science Translational Medicine, researchers at the University of California, Irvine, reported that they successfully modified human bone marrow stem cells to have stiffness-sensing ability so that they can detect cancerous tissue, lock into it and activate therapeutics, while preventing some toxic side effects.
Then, the researchers effectively and safely employed this stem cell-targeting system in mice to treat metastatic breast cancer that had spread to the lung.
They first transplanted the engineered stem cells to let them find and settle into the tumor site where they secreted enzymes called cytosine deaminase.
The mice were then administered an inactive chemotherapy called prodrug 5-flurocytosine, which was triggered into action by the tumor site enzymes.
Weian Zhao, associate professor of pharmaceutical sciences, who led the study, said his team specifically focused on metastatic cancer, which comes when the disease spreads to other parts of the body, because metastatic tumors are particularly deadly and the cause of 90 percent of cancer deaths.
"This is a new paradigm for cancer therapy," Zhao said. "We are going in a direction that few have explored before, and we hope to offer an alternative and potentially more effective cancer treatment."
Zhao added that this stem cell-targeting approach can provide an alternative to many forms of chemotherapy, which has a number of bad side effects, including harming healthy cells.
"Our new type of treatment only targets metastatic tissue, which enables us to avoid some of conventional chemotherapy's unwanted side effects," said Zhao.
He added the technology can be applicable to other metastases, because many solid tumors have the hallmark of being stiffer than normal tissue.
"This is why our system is innovative and powerful, as we don't have to spend the time to identify and develop a new genetic or protein marker for every kind of cancer," Zhao said.
So far, the Zhao team has done preclinical animal studies to demonstrate that the treatment works and is safe, and they hoped to transition to human studies in the near future.
They were currently expanding to include other type of cells, including cancer tissue-sensing, engineered immune-system T cells called CAR-T to treat metastasizing breast and colon cancers.
They also planned to transform the technology for other diseases such as fibrosis and diabetes, which result in stiffening of otherwise healthy tissue.