Genome complexity: automatic mechanism to kill early cancer (Introduction)

by David Turell , Thursday, November 01, 2018, 23:42 (1995 days ago) @ David Turell

The RNA mechanism has been found:

https://www.sciencedaily.com/releases/2018/10/181029084050.htm

"A kill code is embedded in every cell in the body whose function may be to cause the self-destruction of cells that become cancerous, reports a new Northwestern Medicine study. 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.

"The code is embedded in large protein-coding ribonucleic acids (RNAs) and in small RNAs, called microRNAs, which scientists estimate evolved more than 800 million years ago in part to protect the body from cancer. The toxic small RNA molecules also are triggered by chemotherapy, Northwestern scientists report.

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"In published research in 2017, Peter showed cancer cells die when he introduced certain small RNA molecules. He also discovered cancer cells treated with the RNA molecules never become resistant because the molecules simultaneously eliminate multiple genes cancer cells need for survival.

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"But he didn't know what mechanism caused the cells to self-destruct. What he knew was a sequence of just six nucleotides (6mers) present in small RNAs made them toxic to cancer cells. Nucleotides are organic molecules that are the building blocks of DNA and RNA. They are G, C, A or T (in DNA), or U (in RNA).

"In the first of the new studies, Peter then tested all 4,096 different combinations of nucleotide bases in the 6mers until he found the most toxic combination, which happens to be G-rich, and discovered microRNAs expressed in the body to fight cancer use this 6mer to kill cancer cells.

"In the second new study, Peter showed 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. Peter's group found about three percent of all protein-coding large RNAs in the genome can be processed in this way.

"'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."

Comment: It is obvious this mechanism doesn't work all the time, but is another example of automaticity the cells exhibit. Obviously it is an intelligent response.