MYC Dependency in GLS1 and NAMPT is a Therapeutic Vulnerability in Multiple Myeloma

Multiple myeloma (MM) is an incurable hematological malignancy in which MYC alterations contribute to the malignant phenotype. Nevertheless, MYC lacks therapeutic druggability. Here, we leveraged large-scale loss-of-function screens and conducted a small molecule screen to identify genes and pathways with enhanced essentiality correlated with expression. We reported a specific gene dependency in glutaminase (GLS1), essential for the viability and proliferation of MYC overexpressing cells. Conversely, the analysis of isogenic models, as well as cell lines dataset (CCLE) and patient datasets, revealed GLS1 as a non-oncogenic dependency in MYC-driven cells. We functionally delineated the differential modulation of glutamine to maintain mitochondrial function and cellular biosynthesis in overexpressing cells. Furthermore, we observed that pharmaceutical inhibition of NAMPT selectively affects upregulated cells. We demonstrate the effectiveness of combining GLS1 and NAMPT inhibitors, suggesting that targeting glutaminolysis and NAD synthesis may be a promising strategy to target MYC-driven MM.