Elongator Complex Regulates MCL1 Dependency Via IRE1-XBP1 Axis of the ER Stress Response Pathway in Multiple Myeloma

Evasion of apoptosis is a hallmark of cancer wherein overexpression and amplification of pro-survival BCL2-family genes like MCL1 is a common observation. MCL1 is frequently amplified in many hematological cancers like Multiple Myeloma (MM) that depend on it for survival. BH3 mimetic drugs, like the BCL2-specific inhibitor Venetoclax, have been successfully used in the clinic to treat certain cancers, and MCL1-selective inhibitors are currently in clinical development. While inhibition of MCL1 displays promising preclinical activity, many cancer models display acquired or intrinsic resistance to MCL1 inhibitors (MCL1i). As MCL1-targeted therapies progress clinically, understanding mechanisms that lead to resistance will be important to not only identify therapeutically-exploitable targets to combat resistance, but to also determine if these biomarkers could stratify patients most likely to respond to an MCL1i.