Project description:Identification of new therapeutic targets in liver cancer remains critical. Chromatin regulating complexes are frequently mutated in liver cancer suggesting dysregulation of chromatin environments is a key feature driving liver cancer. We applied a focused CRISPR library targeting all genes involved in chromatin regulation to determine if the altered chromatin state of hepatocellular carcinoma cells could be targeted. The focused approach allowed us to test multiple cell lines in both 2D and 3D growth conditions which revealed striking differences in the essentiality of genes involved in ubiquitination and uncovered multiple chromatin regulators that are essential in 2D but whose loss promotes growth in 3D. We found the menin-MLL complex as among the strongest essential genes in all screens and deeply characterized the mechanism menin-MLL uses to promote hepatocellular carcinoma growth. Inhibition of menin-MLL led to global changes in occupancy of the complex and concomitant decreases in H3K4me3 and gene expression. A surprising increase in chromatin accessibility at sites not bound by menin-MLL was associated with recruitment of the pioneer transcription factor complex NF-Y. A screen of chromatin regulators in the presence of the menin-MLL inhibitor SNDX-5613 revealed a synergy between NF-YB loss and menin-MLL inhibition. Together these data show that menin-MLL is necessary for cell survival in HCC and cooperates with NF-Y to regulate transcription.
Project description:Identification of new therapeutic targets in liver cancer remains critical. Chromatin regulating complexes are frequently mutated in liver cancer suggesting dysregulation of chromatin environments is a key feature driving liver cancer. We applied a focused CRISPR library targeting all genes involved in chromatin regulation to determine if the altered chromatin state of hepatocellular carcinoma cells could be targeted. The focused approach allowed us to test multiple cell lines in both 2D and 3D growth conditions which revealed striking differences in the essentiality of genes involved in ubiquitination and uncovered multiple chromatin regulators that are essential in 2D but whose loss promotes growth in 3D. We found the menin-MLL complex as among the strongest essential genes in all screens and deeply characterized the mechanism menin-MLL uses to promote hepatocellular carcinoma growth. Inhibition of menin-MLL led to global changes in occupancy of the complex and concomitant decreases in H3K4me3 and gene expression. A surprising increase in chromatin accessibility at sites not bound by menin-MLL was associated with recruitment of the pioneer transcription factor complex NF-Y. A screen of chromatin regulators in the presence of the menin-MLL inhibitor SNDX-5613 revealed a synergy between NF-YB loss and menin-MLL inhibition. Together these data show that menin-MLL is necessary for cell survival in HCC and cooperates with NF-Y to regulate transcription.
Project description:Identification of new therapeutic targets in liver cancer remains critical. Chromatin regulating complexes are frequently mutated in liver cancer suggesting dysregulation of chromatin environments is a key feature driving liver cancer. We applied a focused CRISPR library targeting all genes involved in chromatin regulation to determine if the altered chromatin state of hepatocellular carcinoma cells could be targeted. The focused approach allowed us to test multiple cell lines in both 2D and 3D growth conditions which revealed striking differences in the essentiality of genes involved in ubiquitination and uncovered multiple chromatin regulators that are essential in 2D but whose loss promotes growth in 3D. We found the menin-MLL complex as among the strongest essential genes in all screens and deeply characterized the mechanism menin-MLL uses to promote hepatocellular carcinoma growth. Inhibition of menin-MLL led to global changes in occupancy of the complex and concomitant decreases in H3K4me3 and gene expression. A surprising increase in chromatin accessibility at sites not bound by menin-MLL was associated with recruitment of the pioneer transcription factor complex NF-Y. A screen of chromatin regulators in the presence of the menin-MLL inhibitor SNDX-5613 revealed a synergy between NF-YB loss and menin-MLL inhibition. Together these data show that menin-MLL is necessary for cell survival in HCC and cooperates with NF-Y to regulate transcription.
Project description:Identification of new therapeutic targets in hepatocellular carcinoma (HCC) remains critical. Chromatin regulating complexes are frequently mutated or aberrantly expressed in HCC, suggesting dysregulation of chromatin environments is a key feature driving liver cancer. To investigate whether the altered chromatin state in HCC cells could be targeted, we designed and utilized an epigenome-focused CRISPR library that targets all genes involved in chromatin regulation. This focused approach allowed us to test multiple cell lines in both 2D and 3D growth conditions, which revealed striking differences in the essentiality of genes involved in ubiquitination and uncovered multiple chromatin regulators vital for HCC cell survival in 2D but whose loss promoted growth in 3D. We found the core subunits of the menin-MLL1 complex among the strongest essential genes for HCC survival in all screens and thoroughly characterized the mechanism through which menin-MLL1 complex promote HCC cell growth. Inhibition of the menin-MLL1 interaction led to global changes in occupancy of the complex and concomitant decreases in H3K4me3 and gene expression. We observed that increased chromatin accessibility at sites not bound by menin-MLL1 was associated with the recruitment of the pioneer transcription factor complex NF-Y. A CRISPR/Cas9 screen of chromatin regulators in the presence of the menin-MLL1 inhibitor SNDX-5613 revealed a synergistic effect on cell death when combining NF-YB loss and menin-MLL1 interaction inhibition. Together, these data show that menin-MLL1 is necessary for HCC cell survival and cooperates with NF-Y to regulate oncogenic gene transcription.
Project description:Chromosomal translocations affecting Mixed Lineage Leukemia (MLL) gene result in acute leukemias resistant to therapy. The leukemogenic activity of MLL fusion proteins is dependent on their interaction with menin, providing basis for therapeutic intervention. Here we report development of novel, highly potent and orally bioavailable small molecule inhibitors of the menin-MLL interaction, MI-463 and MI-503, show their profound effects in MLL leukemia cells and substantial survival benefit in mice models of MLL leukemia. Finally, we demonstrate efficacy of these compounds in primary samples derived from MLL leukemia patients. Overall, we demonstrate for the first time that pharmacologic inhibition of the menin-MLL interaction represents an effective treatment for MLL leukemias in vivo and provide advanced molecular scaffold for clinical lead identification.
Project description:Treatment of cells carrying MLL-rearrangements with VTP-50469 (specific Menin-MLL1 inhibitor) displaces Menin from high molecular weight complexes and chromatin genome-wide. Since VTP-50469 block Menin interaction with MLL1 we tested using chip-seq if treatment with VTP-50469 also displaces MLL1 or MLL-fusions from chromatin. We found that the VTP-50469 treatment displaced MLL-fusions from only a subset of MLL-fusion binding sites. Since DOT1L is associated with MLL-AF9 we then tested if displacement of MLL1 also leads to loss of DOT1L association with chromatin on MLL-AF9 binding sites. We found that DOT1L binds to thousands of genes, treatment with VTP-50469 leads to genome wide loss of DOT1L binding including the same subset of MLL-fusion binding sites.