A cellular signal that promotes tumor growth in mice can be reprogrammed with the CRISPR-Cas9 genome editing system into a signal that shrinks the tumor, reports a paper published online this week in Nature Methods.
Eukaryotic cells - which include cells of both plants and animals - live and die by the signals they receive to regulate their gene expression. In the study, Weiren Huang, Zhiming Cai and colleagues manipulated this signaling pathway using the CRISPR-Cas9 system to regulate gene expression at the target site.
The authors modified the RNA component of the CRISPR-Cas9 system to be activated by a signal that normally promotes tumor growth. The activated CRISPR-Cas9 system then brings a transcriptional activator to two tumor suppressor genes, thus stopping the growth of the cancer cells. In a second example the authors reprogrammed cells to respond to an oncogenic stimulus by inducing the expression of genes that trigger cell death. They show that tumors in mice carrying these reprogrammed cells were much smaller than tumors in control animals.