The OTUD6B-LIN28B-MYC axis determines cell cycle progression in multiple myeloma

ABSTRACT: Deubiquitylases (DUBs) remove ubiquitin from proteins. In the context of cancer, their inhibition can induce the degradation of oncoproteins, that may otherwise be “undruggable”. Multiple myeloma (MM) is the second most common hematological malignancy with poor outcome and high sensitivity towards ubiquitin-proteasome-system (UPS) inhibitory therapies. However, the role of DUBs in MM pathophysiology and therapy has remained elusive. Starting from genetic screening for DUB dependencies in MM, we here identify OTUD6B as a central vulnerability in MM that drives the G1/S cell cycle transition by means of deubiquitylating and stabilizing LIN28B subsequent to LIN28B phosphorylation. LIN28B regulates miRNA biogenesis and exerts high expression in embryonic stem cells that becomes re-established in certain tumors, including MM. Binding of LIN28B at G1/S activates OTUD6B, which otherwise remains in a catalytically inactive state. As a consequence, stabilized LIN28B drives MYC expression via inhibition of let7 microRNAs, which in turn allows for a rapid transition of MM cells from G1 to S phase. Analyses of primary MM patient samples reveal a positive correlation of OTUDB6B expression with poor outcome, high MYC expression and MYC target gene induction, suggesting that high MYC levels in MM result from an activation of the OTUD6B-LIN28B nexus. Together, we here specify phosphorylation and cell cycle-dependent substrate binding as a means by which OTUD6B becomes activated to drive the G1/S transition via the LIN28B-MYC axis and nominate OTUD6B and LIN28B as actionable vulnerabilities in MM.

INSTRUMENT(S): Q Exactive HF

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Kidney

DISEASE(S): Multiple Myeloma

SUBMITTER: Jana Zecha  

LAB HEAD: Bernhard Kuster

PROVIDER: PXD027480 | Pride | 2022-10-12

REPOSITORIES: Pride