Prevalent aberrant condensates of onco-fusion transcription factors and their dissolution as potential cancer therapy
Ontology highlight
ABSTRACT: Cancer-associated chromosomal rearrangements can result in the expression of numerous pathogenic fusion proteins. The mechanisms via which the fusion proteins contribute to oncogenesis are largely unknown and effective therapies for fusion-associated cancers are lacking. Here, we comprehensively scrutinized fusion proteins found in various cancers. We found that many fusion proteins are composed of phase separation-prone domains (PS) and DNA-binding domains (DBD), and these fusions have strong correlation with aberrant gene expression patterns. Furthermore, we established a high-throughput screening method, named DropScan, to screen drugs capable of modulating aberrant condensates. One of the drugs identified via DropScan, LY2835219, effectively dissolved the condensates in reporter cells lines expressing Ewing sarcoma fusions and partially rescued the abnormal expression of target genes. Our results indicate that aberrant phase separation is likely a common mechanism for these PS-DBD fusion-related cancers, and suggest that modulating aberrant phase separation is a potential route to treat these diseases.
Project description:Cancer-associated chromosomal rearrangements can result in the expression of numerous pathogenic fusion proteins. The mechanisms via which the fusion proteins contribute to oncogenesis are largely unknown and effective therapies for fusion-associated cancers are lacking. Here, we comprehensively scrutinized fusion proteins found in various cancers. We found that many fusion proteins are composed of phase separation-prone domains (PS) and DNA-binding domains (DBD), and these fusions have strong correlations with aberrant gene expression patterns. Furthermore, we established a high-throughput screening method, named DropScan, to screen drugs capable of modulating aberrant condensates. One of the drugs identified via DropScan, LY2835219, effectively dissolved the condensates in reporter cell lines expressing Ewing sarcoma fusions and partially rescued the abnormal expression of target genes. Our results indicate that aberrant phase separation is likely a common mechanism for these PS-DBD fusion-related cancers, and suggest that modulating aberrant phase separation is a potential route to treat these diseases.
Project description:Chromosome translocation is known to generate oncogenes such as SS18-SSX1, but the underlying mechanism remains unknown. Here we show that enhanced phase separation acquired by translocation mediates oncogenic transformation. SSX fusion dramatically enhances the phase separation property of SS18 protein through H2AK119ub. Super condensates generated by SS18-SSX recruit acetyltransferases CBP/P300 as wild type SS18, but exclude HDACs such that H3K27ac accumulates abnormally at loci from those normally occupied by SS18, resulting aberrant silencing and activation of target genes. Consistently, we show that inhibition of H3K27ac can attenuate the tumorigenicity of the fusion oncoprotein. These results provide the first case for phase separation as a transforming event to generate oncogene and super phase separation can be targeted for cancer therapy.
Project description:Chromosome translocation is known to generate oncogenes such as SS18-SSX1, but the underlying mechanism remains unknown. Here we show that enhanced phase separation acquired by translocation mediates oncogenic transformation. SSX fusion dramatically enhances the phase separation property of SS18 protein through H2AK119ub. Super condensates generated by SS18-SSX recruit acetyltransferases CBP/P300 as wild type SS18, but exclude HDACs such that H3K27ac accumulates abnormally at loci from those normally occupied by SS18, resulting aberrant silencing and activation of target genes. Consistently, we show that inhibition of H3K27ac can attenuate the tumorigenicity of the fusion oncoprotein. These results provide the first case for phase separation as a transforming event to generate oncogene and super phase separation can be targeted for cancer therapy.
Project description:Chromosome translocation is known to generate oncogenes such as SS18-SSX1, but the underlying mechanism remains unknown. Here we show that enhanced phase separation acquired by translocation mediates oncogenic transformation. SSX fusion dramatically enhances the phase separation property of SS18 protein through H2AK119ub. Super condensates generated by SS18-SSX recruit acetyltransferases CBP/P300 as wild type SS18, but exclude HDACs such that H3K27ac accumulates abnormally at loci from those normally occupied by SS18, resulting aberrant silencing and activation of target genes. Consistently, we show that inhibition of H3K27ac can attenuate the tumorigenicity of the fusion oncoprotein. These results provide the first case for phase separation as a transforming event to generate oncogene and super phase separation can be targeted for cancer therapy.
Project description:Chromosome translocation is known to generate oncogenes such as SS18-SSX1, but the underlying mechanism remains unknown. Here we show that enhanced phase separation acquired by translocation mediates oncogenic transformation. SSX fusion dramatically enhances the phase separation property of SS18 protein through H2AK119ub. Super condensates generated by SS18-SSX recruit acetyltransferases CBP/P300 as wild type SS18, but exclude HDACs such that H3K27ac accumulates abnormally at loci from those normally occupied by SS18, resulting aberrant silencing and activation of target genes. Consistently, we show that inhibition of H3K27ac can attenuate the tumorigenicity of the fusion oncoprotein. These results provide the first case for phase separation as a transforming event to generate oncogene and super phase separation can be targeted for cancer therapy.
Project description:Chromosome translocation is known to generate oncogenes such as SS18-SSX1, but the underlying mechanism remains unknown. Here we show that enhanced phase separation acquired by translocation mediates oncogenic transformation. SSX fusion dramatically enhances the phase separation property of SS18 protein through H2AK119ub. Super condensates generated by SS18-SSX recruit acetyltransferases CBP/P300 as wild type SS18, but exclude HDACs such that H3K27ac accumulates abnormally at loci from those normally occupied by SS18, resulting aberrant silencing and activation of target genes. Consistently, we show that inhibition of H3K27ac can attenuate the tumorigenicity of the fusion oncoprotein. These results provide the first case for phase separation as a transforming event to generate oncogene and super phase separation can be targeted for cancer therapy.
Project description:Chromosome translocation is known to generate oncogenes such as SS18-SSX1, but the underlying mechanism remains unknown. Here we show that enhanced phase separation acquired by translocation mediates oncogenic transformation. SSX fusion dramatically enhances the phase separation property of SS18 protein through H2AK119ub. Super condensates generated by SS18-SSX recruit acetyltransferases CBP/P300 as wild type SS18, but exclude HDACs such that H3K27ac accumulates abnormally at loci from those normally occupied by SS18, resulting aberrant silencing and activation of target genes. Consistently, we show that inhibition of H3K27ac can attenuate the tumorigenicity of the fusion oncoprotein (we do not have the data in your figures?). These results provide the first case for phase separation as a transforming event to generate oncogene and super phase separation can be targeted for cancer therapy.
Project description:Chromosome translocation is known to generate oncogenes such as SS18-SSX1, but the underlying mechanism remains unknown. Here we show that enhanced phase separation acquired by translocation mediates oncogenic transformation. SSX fusion dramatically enhances the phase separation property of SS18 protein through H2AK119ub. Super condensates generated by SS18-SSX recruit acetyltransferases CBP/P300 as wild type SS18, but exclude HDACs such that H3K27ac accumulates abnormally at loci from those normally occupied by SS18, resulting aberrant silencing and activation of target genes. Consistently, we show that inhibition of H3K27ac can attenuate the tumorigenicity of the fusion oncoprotein (we do not have the data in your figures?). These results provide the first case for phase separation as a transforming event to generate oncogene and super phase separation can be targeted for cancer therapy.
Project description:HIPPO-YAP/TAZ signaling has been implicated in supratentorial ependymoma formation from neural progenitor cells (NPC) in the brain, however, the underlying mechanisms to trigger the neural progenitor cell transformation remains elusive. Here, we uncover that patient-derived tumorigenic YAP-fusion proteins (YAP-MAMLD1 and C11ORF95-YAP) promote ependymoma tumorigenesis through forming liquid-liquid phase-separated condensates. Intrinsically disordered regions (IDR) in the fusion proteins promote oligomerization of YAP-transcriptional co-activators and self-assembly of nuclear puncta-like membrane-less organelles. Phase separation of YAP-fusion proteins further facilitates the compartmentalization of transcriptional coactivators, BRD4 and MED1, resulting in pervasive enhancer landscape changes and exclusion of transcriptional repressors such as PRC2 complexes. YAP-fusion proteins-induced nuclear puncta recruit RNA polymerase II to promote transcriptional bursting of multiple oncogenic pathways. Moreover, we show that IDR-mediated phase separation is necessary for YAP-fusion protein-induced tumor formation. Distinct YAP fusion-proteins identified in other human tumors also encompass IDR features. Together, our data suggest that IDR-mediated phase separation is an integral component of YAP-fusion protein-induced tumorigenesis and might serve as a therapeutic target in supratentorial ependymoma.
Project description:HIPPO-YAP/TAZ signaling has been implicated in supratentorial ependymoma formation from neural progenitor cells (NPC) in the brain, however, the underlying mechanisms to trigger the neural progenitor cell transformation remains elusive. Here, we uncover that patient-derived tumorigenic YAP-fusion proteins (YAP-MAMLD1 and C11ORF95-YAP) promote ependymoma tumorigenesis through forming liquid-liquid phase-separated condensates. Intrinsically disordered regions (IDR) in the fusion proteins promote oligomerization of YAP-transcriptional co-activators and self-assembly of nuclear puncta-like membrane-less organelles. Phase separation of YAP-fusion proteins further facilitates the compartmentalization of transcriptional coactivators, BRD4 and MED1, resulting in pervasive enhancer landscape changes and exclusion of transcriptional repressors such as PRC2 complexes. YAP-fusion proteins-induced nuclear puncta recruit RNA polymerase II to promote transcriptional bursting of multiple oncogenic pathways. Moreover, we show that IDR-mediated phase separation is necessary for YAP-fusion protein-induced tumor formation. Distinct YAP fusion-proteins identified in other human tumors also encompass IDR features. Together, our data suggest that IDR-mediated phase separation is an integral component of YAP-fusion protein-induced tumorigenesis and might serve as a therapeutic target in supratentorial ependymoma.