TEL AVIV, Israel, Feb. 23 (UPI) -- Based on knowledge that healthy people can live full lives with dormant cancer cells in their bodies never causing a health problem, scientists in Israel found a method to turn the cells off by using a drug that blocks their ability to grow.
The proof-of-concept drug prevents osteosarcoma, or bone cancer, cells from communicating with healthy cells around them, stopping growth in lab experiments, Tel Aviv University researchers report.
The researchers found three microRNAs at low levels in aggressive tumors but at much higher levels in dormant tumors. In a dish, the researchers introduced selected microRNAs to cancer cells, finding they had less of an ability to communicate with normal cells.
"We saw that the osteosarcoma cells treated with the selected microRNAs were unable to recruit blood vessels to feed their growth," Dr. Ronit Satchi-Fainaro, head of the cancer angiogenesis and nanomedicine laboratory at Tel Aviv University, said in a press release. "In order to keep these microRNAs stable in the blood, we needed to encapsulate them in a nanoparticle that circulates in healthy blood vessels, but that disembark and deliver the drug therapy at the leaky blood vessels that exist at tumor sites. We designed a nanomedicine that would have a special activation method at the tumor site in the target cell."
For the study, published in ACS Nano, the researchers tested the nanoparticle wrapper method of delivering the microRNAs to the tumor site in mice. Mice treated with the drug survived for six months with the cancer, which Satchi-Fainaro said is the equivalent of 25 years of human life.
In addition to planning for clinical trials using the nanomedicine developed at her lab, Satchi-Fainaro said research for similar ways to send other cancers into a dormant phase is underway.
"We wanted to understand what causes the cancer cells to 'switch on' in these cases," Satchi-Fainaro said. "As long as cancer cells remain asymptomatic and dormant, cancer is a manageable disease. Many people live with thyroid lesions without their knowledge, for example. Ours is a very optimistic approach, and we believe it could apply to other cancers as well."