Breakthrough Therapy Stops Liver Cancer in Mice

Reported June 16, 2009

(Ivanhoe Newswire) -- A new study suggests microRNA replacement therapy could stop liver cancer in its tracks.

Researchers delivered a single small RNA, using an adeno-associated virus (AAV), to cancer cells in mice with an extremely aggressive form of liver cancer. MicroRNAs control gene expression and are commonly lost in cancerous tumors.

"Mice given the control virus [without microRNA] showed no change in the growth rate of their tumors, and within three weeks, the cancer had taken over," Joshua Mendell of Johns Hopkins University School of Medicine was quoted as saying. "When we gave them the microRNA-carrying virus, some animals showed essentially complete regression of their tumors." In other cases, he said, the tumors were much smaller and there were fewer of them.

Researchers were also amazed by how specifically the microRNA affected cancer cells, while leaving normal cells unscathed. "We found that tumor cells are exquisitely sensitive--they not only stopped proliferating, but they actually died," said Mendell. Meanwhile, the mice showed no evidence of any damage to their normal liver tissue.

There is a dire need for new strategies to combat primary liver cancers, which researchers said is the third leading cause of cancer deaths and the fifth most common malignancy worldwide. They hope that the microRNA replacement strategy will be effective against other cancers, as well. Scientists are currently working on methods to deliver microRNAs to other types of tissue.

SOURCE: CELL, June 12, 2009