CRISPR/Cas9 within the SIRIC program
CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) is a gene editing system.
Genetic screening is a unique opportunity to study the characteristics of cancer cells and, in particular, resistance mechanisms by identifying inactivated genes that create resistance to a given treatment.
This innovative technique allows us to address questions raised by the SIRIC program with a transverse approach.
In vivo CRISPR: a promising technical development
The deployment of CRISPR in vivo would be a major advantage to explore treatment resistance but it's also a significant challenge due to the intrinsic restrictions of 3D cultures.
In 2018, Aurélien Boré (research engineer), was recruted thanks to SIRIC support. His mission is the development of genetic screening technical conditions in vivo.
Our CRISPR projects
Technological development and support of the CRISPR platform are structuring actions that reinforce infrastructures necessary for the SIRIC program.
The SIRIC programs 'pediatric cancers' and 'uveal melanoma' rely on this technology:
3 projects in the frame of the pediatric cancer program use genetic screening to identify new therapies in Ewing sarcoma (destabilization of the EWSR1-FLI1 oncogene and seeking vulnerabilities in the context of STAG2 mutations) and rhabdoid tumors (tyrosine kinase inhibitors).
For the uveal melanoma program, an unexpected role of BAP1 in gene activation was demonstrated by Campagne et al thanks to an integrative approach based on isogenic cell lines generated with CRISPR/Cas9.
How does the CRISPR technique work ?
This method can precisely 'turn off' a specific gene in a given cell to study its function. The first step is to select a guide RNA (gRNA) that recognizes the gene in order to target the Cas9 protein. This protein will cut the DNA and provoke mutations.
gRNA librairies allow the interrogation of the function of a group of genes at the same time, this is described as genetic screening. Before CRISPR, genetic screenings were, for the most part, limited to specific model organisms.
CRISPR allows us to carry out genetic screens in new experimental models and paves the way for the identification of genes whose inactivation has an influence on a specific phenotype (postive screen) or which are essential in certain contexts (negative screen). We can also discover genes implicated in treatment resistance or identify weaknesses in cancerous cells that could become therapeutic targets.