CHICAGO, Nov. 1 (Xinhua) -- A kill code that is embedded in large protein-coding ribonucleic acids (RNAs) and in small RNAs, called microRNAs, in human body may function to cause the self-destruction of cells that become cancerous, a Northwestern Medicine study shows.
As soon as the cell's inner bodyguards sense it is mutating into cancer, they punch in the kill code to extinguish the mutating cell.
In a research in 2017, researchers at Northwestern University (NU) found that cancer cells die when they introduced certain small RNA molecules. They also discovered cancer cells treated with the RNA molecules never become resistant because the molecules simultaneously eliminate multiple genes cancer cells need for survival. A sequence of just six nucleotides (6mers) present in small RNAs made them toxic to cancer cells.
In the first of the new studies, NU researchers tested all 4,096 different combinations of nucleotide bases in the 6mers until they found the most toxic combination, and discovered microRNAs expressed in the body to fight cancer use this 6mer to kill cancer cells.
In the second new study, the researchers found the cells chop a gene (Fas ligand) involved in cancer cell growth into small pieces that then act like microRNAs and are highly toxic to cancer. They found about three percent of all protein-coding large RNAs in the genome can be processed in this way.
"Now that we know the kill code, we can trigger the mechanism without having to use chemotherapy and without messing with the genome. We can use these small RNAs directly, introduce them into cells and trigger the kill switch," said lead author Marcus E. Peter, professor of cancer metabolism at NU Feinberg School of Medicine.
"Based on what we have learned in these two studies, we can now design artificial microRNAs that are much more powerful in killing cancer cells than even the ones developed by nature," Peter said.
In the next step, the researchers will explore multiple ways to trigger the embedded kill code to kill cancer cells, a novel form of therapy.
The study was published on Oct. 29 in Nature Communications.
