Abstract 242: Identification of biomarkers predicting sensitivity to GLS1 inhibition using a CRISPR screen

The conditional essential amino acid glutamine is utilized by tumors to sustain bioenergetic requirements in a nutrient-poor microenvironment. Based on this specific tumor need, efforts have been made to target the glutamine metabolism using glutaminase inhibitors. This approach has demonstrated activity in preclinical models and in a range of phase I studies. It was shown that a subset of models/patients are benefiting from glutaminase inhibition, however, biomarkers predicting sensitivity to GLS1 inhibitors are lacking. The objective of this study is to identify molecular predictors of the sensitivity towards GLS1 inhibition. Using the cBioportal, we analyzed the most prevalent genetic deficiencies in Triple Negative Breast cancers, Kidney cancers, Acute Myeloid Leukemia and Multiple Myeloma. From this analysis, a library of CRISPR gRNA including the most disease relevant LOF linked-genes was created. Individual cell lines stably expressing Cas9 were used for a focused CRISPR screen in the presence of suboptimal doses of GLS1 inhibitor. The sgRNA library mimicking the major genetic deficiencies identified from the cBioportal datamining was delivered in pool lentiviral particles. Genes deficiencies associated with increased GLS1 sensitivity were identified with sgRNA targeted NGS sequencing of the remaining cell population at treatment completion. We present the setup and validation of an innovative experimental design for the identification of biomarkers predictive to GLS1 inhibition with the aim to identify gene deficiencies associated with increased sensitivity to GLS1 inhibitors that could be used as predictive biomarkers in the clinic. Citation Format: Christophe Henry, Karine Berthelot, Christophe Lanneau, Cécile Orsini, Dimitri Gorge-Bernat, Isabelle Meaux, Dorine Chassin, Jürgen Moll, Berangere Thiers, David Machnik, Laurent Debussche. Identification of biomarkers predicting sensitivity to GLS1 inhibition using a CRISPR screen [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 242.