Project description:MYCN amplification in neuroblastoma leads to aberrant expression of MYCN oncoprotein, which binds active genes promoting transcriptional amplification. Yet how MYCN coordinates transcription elongation to meet productive transcriptional amplification and which elongation machinery represents MYCN-driven vulnerability remain to be identified. We conducted a targeted screen of transcription elongation factors and identified the super elongation complex (SEC) as a unique vulnerability in MYCN-amplified neuroblastomas. MYCN directly binds EAF1 and recruits SEC to enhance processive transcription elongation. Depletion of EAF1 or AFF1/AFF4, another core subunit of SEC, leads to a global reduction in transcription elongation and elicits selective apoptosis of MYCN-amplified neuroblastoma cells. A combination screen reveals SEC inhibition synergistically potentiates the therapeutic efficacies of FDA-approved BCL2 antagonist ABT-199, in part due to suppression of MCL1 expression, both in MYCN-amplified neuroblastoma cells and in patient-derived xenografts. These findings identify disruption of the MYCN-SEC regulatory axis as a promising therapeutic strategy in neuroblastoma.
Project description:Transcriptional dysregulation plays a major role in the development and progression of human tumors such as pediatric neuroblastoma. Therefore, we sought to elucidate the relationship between genes required for neuroblastoma cell growth and survival and the transcriptional core regulatory circuitry (CRC) that controls the gene expression program. A genome-scale CRISPR-Cas9 screen for oncogenic dependencies revealed that 143 genes are essential for cell survival and growth in neuroblastoma relative to other cancers, including many super-enhancer (SE) regulated transcription factors. Genome-wide occupancy analysis of transcription factor binding demonstrated that at least six of these transcription factors were both dependency genes and components of the CRC in MYCN-amplified neuroblastoma including: HAND2, ISL1, PHOX2B, GATA3, TBX2, and MEIS2. Binding sites for these transcription factors were clustered within a few hundred base pairs in their own enhancers and the enhancers of downstream target genes, which surprisingly included 40% of the independently determined neuroblastoma dependency genes. This profound level of transcriptional control of oncogenesis through self-reinforcing transcriptional circuits led us to test combinatorial pharmacological inhibition of transcriptional initiation and elongation, which synergistically induced tumor cell death, supporting drugging transcription as a means to advance the treatment of high risk neuroblastoma.
Project description:Transcriptional dysregulation plays a major role in the development and progression of human tumors such as pediatric neuroblastoma. Therefore, we sought to elucidate the relationship between genes required for neuroblastoma cell growth and survival and the transcriptional core regulatory circuitry (CRC) that controls the gene expression program. A genome-scale CRISPR-Cas9 screen for oncogenic dependencies revealed that 143 genes are essential for cell survival and growth in neuroblastoma relative to other cancers, including many super-enhancer (SE) regulated transcription factors. Genome-wide occupancy analysis of transcription factor binding demonstrated that at least six of these transcription factors were both dependency genes and components of the CRC in MYCN-amplified neuroblastoma including: HAND2, ISL1, PHOX2B, GATA3, TBX2, and MEIS2. Binding sites for these transcription factors were clustered within a few hundred base pairs in their own enhancers and the enhancers of downstream target genes, which surprisingly included 40% of the independently determined neuroblastoma dependency genes. This profound level of transcriptional control of oncogenesis through self-reinforcing transcriptional circuits led us to test combinatorial pharmacological inhibition of transcriptional initiation and elongation, which synergistically induced tumor cell death, supporting Òdrugging transcriptionÓ as a means to advance the treatment of high risk neuroblastoma.
Project description:Transcriptional dysregulation plays a major role in the development and progression of human tumors such as pediatric neuroblastoma. Therefore, we sought to elucidate the relationship between genes required for neuroblastoma cell growth and survival and the transcriptional core regulatory circuitry (CRC) that controls the gene expression program. A genome-scale CRISPR-Cas9 screen for oncogenic dependencies revealed that 143 genes are essential for cell survival and growth in neuroblastoma relative to other cancers, including many super-enhancer (SE) regulated transcription factors. Genome-wide occupancy analysis of transcription factor binding demonstrated that at least six of these transcription factors were both dependency genes and components of the CRC in MYCN-amplified neuroblastoma including: HAND2, ISL1, PHOX2B, GATA3, TBX2, and MEIS2. Binding sites for these transcription factors were clustered within a few hundred base pairs in their own enhancers and the enhancers of downstream target genes, which surprisingly included 40% of the independently determined neuroblastoma dependency genes. This profound level of transcriptional control of oncogenesis through self-reinforcing transcriptional circuits led us to test combinatorial pharmacological inhibition of transcriptional initiation and elongation, which synergistically induced tumor cell death, supporting Òdrugging transcriptionÓ as a means to advance the treatment of high risk neuroblastoma.
Project description:A small set of interconnected lineage-specific transcription factors (TFs) form a core regulatory circuitry (CRC) that establishes and maintains cell identity and grants selective dependencies of distinct cancer types. However, effective therapies to targeting CRC TFs remain lacking. Here, we show that the best-in-class KDM4 inhibitor QC6352 has a potent anticancer activity in MYCN-driven high-risk neuroblastoma and significantly represses the CRC TFs including MYCN, HAND2, ASCL1, PHOX2B by disrupting the super-enhancers that dominate the expression of CRC TFs. Furthermore, we have developed a combination therapy by integrating QC6352 into cytotoxic chemotherapy, which leads to a complete response of MYCN amplified tumors and a better animal survival. This study reveals that targeting histone lysine demethylase 4 family may transform into a therapeutic strategy in clinic for cancers driven by CRC TFs.
Project description:A small set of interconnected lineage-specific transcription factors (TFs) form a core regulatory circuitry (CRC) that establishes and maintains cell identity and grants selective dependencies of distinct cancer types. However, effective therapies to targeting CRC TFs remain lacking. Here, we show that the best-in-class KDM4 inhibitor QC6352 has a potent anticancer activity in MYCN-driven high-risk neuroblastoma and significantly represses the CRC TFs including MYCN, HAND2, ASCL1, PHOX2B by disrupting the super-enhancers that dominate the expression of CRC TFs. Furthermore, we have developed a combination therapy by integrating QC6352 into cytotoxic chemotherapy, which leads to a complete response of MYCN amplified tumors and a better animal survival. This study reveals that targeting histone lysine demethylase 4 family may transform into a therapeutic strategy in clinic for cancers driven by CRC TFs.
Project description:A small set of interconnected lineage-specific transcription factors (TFs) form a core regulatory circuitry (CRC) that establishes and maintains cell identity and grants selective dependencies of distinct cancer types. However, effective therapies to targeting CRC TFs remain lacking. Here, we show that the best-in-class KDM4 inhibitor QC6352 has a potent anticancer activity in MYCN-driven high-risk neuroblastoma and significantly represses the CRC TFs including MYCN, HAND2, ASCL1, PHOX2B by disrupting the super-enhancers that dominate the expression of CRC TFs. Furthermore, we have developed a combination therapy by integrating QC6352 into cytotoxic chemotherapy, which leads to a complete response of MYCN amplified tumors and a better animal survival. This study reveals that targeting histone lysine demethylase 4 family may transform into a therapeutic strategy in clinic for cancers driven by CRC TFs.
Project description:A small set of interconnected lineage-specific transcription factors (TFs) form a core regulatory circuitry (CRC) that establishes and maintains cell identity and grants selective dependencies of distinct cancer types. However, effective therapies to targeting CRC TFs remain lacking. Here, we show that the best-in-class KDM4 inhibitor QC6352 has a potent anticancer activity in MYCN-driven high-risk neuroblastoma and significantly represses the CRC TFs including MYCN, HAND2, ASCL1, PHOX2B by disrupting the super-enhancers that dominate the expression of CRC TFs. Furthermore, we have developed a combination therapy by integrating QC6352 into cytotoxic chemotherapy, which leads to a complete response of MYCN amplified tumors and a better animal survival. This study reveals that targeting histone lysine demethylase 4 family may transform into a therapeutic strategy in clinic for cancers driven by CRC TFs.
Project description:Bromodomain-containing protein 4 (BRD4) functions as an epigenetic reader and binds to so-called super-enhancer regions of driving oncogenes such as MYC in cancer. We investigated the possibility to target super-enhancer regulated genes in neuroblastoma and in MYCN amplified disease in particular. We used OTX015, the first small-molecule BRD4 inhibitor to enter clinical phase I/II trials in adults, to test the feasibility to specifically target super-enhancer regulated gene-expression in neuroblastoma. BRD4 inhibition lead to significant transcriptional down-regulation of genes that were associated with super-enhancers, supporting the notion that BRD4 preferentially acts at these chromatin sites. BRD4 inhibition not only attenuated MYCN transcription but most significantly affected MYCN-regulated transcriptional programs.