Optimization of Cas9 RNA sequence to reduce its unexpected effects as a microRNA sponge

Cas9 RNA functions as a miRNA sponge. Let-7 is the dominant regulated miRNA by Cas9 RNA. RNA sequence optimization of Cas9 by synonymous mutation improves its safety. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12943-022-01604-x.