Cancer Cell’s Seven Achilles Heels: Considerations for design of anti-cancer drug combinations

Loss of function screens using shRNA and CRISPR are routinely used to identify genes that modulate responses of tumor cells to anti-cancer drugs. Here, by integrating GSEA and CMAP analyses of multiple published shRNA screens, we identified a core set of pathways that affect responses to multiple drugs with diverse mechanisms of action. This suggests that these pathways represent “weak points” or “Achilles heels”, whose mild disturbance should make cancer cells vulnerable to a variety of treatments. These “weak points” include proteasome, protein synthesis, RNA splicing, RNA synthesis, cell cycle, Akt-mTOR, and tight junction-related pathways. Therefore, inhibitors of these pathways are expected to sensitize cancer cells to a variety of drugs. This hypothesis was tested by analyzing the diversity of drugs that synergize with FDA-approved inhibitors of the proteasome, RNA synthesis, and Akt-mTOR pathways. Indeed, the quantitative evaluation indicates that inhibitors of any of these signaling pathways can synergize with a more diverse set of pharmaceuticals, compared to compounds inhibiting targets distinct from the “weak points” pathways. Our findings described here imply that inhibitors of the “weak points” pathways should be considered as primary candidates in a search for synergistic drug combinations. ### Competing Interest Statement The authors have declared no competing interest. * GSEA : Gene Set Enrichment Analysis CMAP : Connectivity Map CRISPR : Clustered Regularly Interspaced Short Palindromic Repeats RNA : Ribonucleic acid DNA : Deoxyribonucleic acid shRNA : short hairpin RNA MDS : Multidimensional Scaling FDR : False Discovery Rate GEO : Gene Expression Omnibus VEGF : Vascular endothelial growth factor EGF : epidermal growth factor EGFR : epidermal growth factor receptor.