Project description:High expression of LIN28B is associated with aggressive malignancy and poor survival. Here, probing MYCN-amplified neuroblastoma as a model system, we show that LIN28B expression is associated with enhanced cell migration in vitro and invasive and metastatic behavior in murine xenografts. Sequence analysis of the polyribosome fraction of LIN28B-expressing neuroblastoma cells revealed let-7 independent enrichment of transcripts encoding components of the translational and ribosomal apparatus, particularly those with higher adenine/uridine (AU)-content, and depletion of transcripts of neuronal developmental programs. We further show that LIN28B utilizes both its cold shock and zinc finger RNA binding domains to preferentially interact with MYCN-induced transcripts of the ribosomal complex, enhancing their translation. These data demonstrate that LIN28B couples the MYCN-driven transcriptional program to enhanced ribosomal translation, thereby implicating LIN28B as a post-transcriptional driver of the metastatic phenotype.
Project description:High expression of LIN28B is associated with aggressive malignancy and poor survival. Here, probing MYCN-amplified neuroblastoma as a model system, we show that LIN28B expression is associated with enhanced cell migration in vitro and invasive and metastatic behavior in murine xenografts. Sequence analysis of the polyribosome fraction of LIN28B-expressing neuroblastoma cells revealed let-7 independent enrichment of transcripts encoding components of the translational and ribosomal apparatus, particularly those with higher Adenine/Uridine (AU)-content, and depletion of GC-rich transcripts of neuronal developmental programs. We further show that LIN28B utilizes both its cold shock and zinc finger RNA binding domains to preferentially interact with MYCN-induced transcripts of the ribosomal complex, enhancing their translation. These data demonstrate that LIN28B couples the MYCN-driven transcriptional program to enhanced ribosomal translation, thereby implicating LIN28B as a post-transcriptional driver of the metastatic phenotype.
Project description:High expression of LIN28B is associated with aggressive malignancy and poor survival. Here, probing MYCN-amplified neuroblastoma as a model system, we show that LIN28B expression is associated with enhanced cell migration in vitro and invasive and metastatic behavior in murine xenografts. Sequence analysis of the polyribosome fraction of LIN28B-expressing neuroblastoma cells revealed let-7 independent enrichment of transcripts encoding components of the translational and ribosomal apparatus, particularly those with higher adenine/uridine (AU)-content, and depletion of transcripts of neuronal developmental programs. We further show that LIN28B utilizes both its cold shock and zinc finger RNA binding domains to preferentially interact with MYCN-induced transcripts of the ribosomal complex, enhancing their translation. These data demonstrate that LIN28B couples the MYCN-driven transcriptional program to enhanced ribosomal translation, thereby implicating LIN28B as a post-transcriptional driver of the metastatic phenotype.
Project description:LIN28B is highly expressed in neuroblastoma and promotes tumorigenesis at least in part through inhibition of let-7 microRNA biogenesis. Here, we report that overexpression of either wild-type LIN28B, or a LIN28B mutant that is unable to bind and inhibit let-7, accelerates the onset and increases the penetrance of MYCN-induced neuroblastoma, potentiates the invasion and migration of transformed sympathetic neuroblasts and drives the distant metastases in vivo. Genome-wide ChIP-seq analysis and co-immunoprecipitation experiments show that LIN28B indirectly binds active gene promoters in neuroblastoma cells through an interaction with ZNF143 and activates the expression of downstream targets, including GSK3B and L1CAM, which are involved in neuronal cell adhesion and migration. These findings reveal an unexpected, let-7-independent function for LIN28B in transcriptional regulation during neuroblastoma pathogenesis.
Project description:LIN28B is highly expressed in neuroblastoma and promotes tumorigenesis at least in part through inhibition of let-7 microRNA biogenesis. Here, we report that overexpression of either wild-type LIN28B, or a LIN28B mutant that is unable to bind and inhibit let-7, accelerates the onset and increases the penetrance of MYCN-induced neuroblastoma, potentiates the invasion and migration of transformed sympathetic neuroblasts and drives the distant metastases in vivo. Genome-wide ChIP-seq analysis and co-immunoprecipitation experiments show that LIN28B indirectly binds active gene promoters in neuroblastoma cells through an interaction with ZNF143 and activates the expression of downstream targets, including GSK3B and L1CAM, which are involved in neuronal cell adhesion and migration. These findings reveal an unexpected, let-7-independent function for LIN28B in transcriptional regulation during neuroblastoma pathogenesis.
Project description: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.