Combinatorial tumor suppressor inactivation efficiently initiates lung adenocarcinoma with therapeutic vulnerabilities

Here, using a quantitative autochthonous mouse model system and performing iterative in vivo functional screens (mainly with programmable multiplexed CRISPR/Cas9-induced genotypes via ultra-deep sequencing of DNA barcoded tumors: Tuba-seq), we uncover genetic and biochemical changes that enable efficient lung tumor initiation in the absence of oncogene alterations. Through the generation of hundreds of diverse combinatorial tumor suppressor alterations, we demonstrate that inactivation of suppressors of the RAS/MAPK and PI3K pathways allows for stepwise and efficient acquisition of growth advantage that can drive the development of oncogene-negative lung adenocarcinoma. Furthermore, we demonstrate that oncogene-negative tumors with activated RAS/MAPK and PI3K pathways are vulnerable to pharmacological inhibition of these signaling axes. Ultra-deep sequencing of DNA barcode amplicon and RNA-seq