Cancer researchers have dreamed that one day they could force tumor cells to change back into normal cells, and scientists at Florida's Mayo Clinic may have found the key.

Their research re-established the mechanism in cancer cells that prevents them from multiplying and forming tumors. It's "an unexpected new biology that provides the code, the software for turning off cancer," says the study's senior investigator, Panos Anastasiadis, Ph.D.

Even though the technique has only been tested on human cells in the lab, researchers hope it can one day turn off cancer growths and restore normal cells without resorting to surgery or chemotherapy.

The researchers found that a protein, which functions as glue in keeping cells together, is regulated by microprocessors called microRNAs. Cells have to reproduce themselves, and normally they replicate until a protein called PLEKHA7 is released that keeps them from continuing to divide. But in cancer, the cells keep dividing. "This produces the equivalent of a speeding car that has a lot of gas and no brakes (the PLEKHA7-microprocessor complex)," said Anastasiadis.

Researchers found they could trigger cancer in cells by removing the microRNA from cells, which prevented them from releasing PLEKHA7. And they discovered they could reverse the process and stop the cancer in its tracks.

The microRNAs are small molecules, and they could be conveyed by an injection directly to tumors to turn off the cancer process, thus reversing the disease.

"By administering the affected microRNAs in cancer cells to restore their normal levels, we should be able to re-establish the brakes and restore normal cell function," Dr. Anastasiadis says. "Initial experiments in some aggressive types of cancer are indeed very promising."

The study was published in Nature Cell Biology.