Project description:Single-cell perturbation assays such as Mosaic-seq enable highly multiplexed functional assessment of enhancers in their endogenous genomic context. By introducing a few computational and experimental improvements, we expanded the Mosaic-seq analysis to capture the secondary gene targets of enhancers. Our analysis of >500 putative enhancers in K562 cells demonstrates that many secondary hits are shared among enhancers targeting different transcriptional factors, which reveals an interwoven enhancer-driven gene regulatory network. Together, our data underscore the flexibility of manipulating gene transcription by modifying enhancer activity.
Project description:Single-cell perturbation assays such as Mosaic-seq enable highly multiplexed functional assessment of enhancers in their endogenous genomic context. By introducing a few computational and experimental improvements, we expanded the Mosaic-seq analysis to capture the secondary gene targets of enhancers. Our analysis of >500 putative enhancers in K562 cells demonstrates that many secondary hits are shared among enhancers targeting different transcriptional factors, which reveals an interwoven enhancer-driven gene regulatory network. Together, our data underscore the flexibility of manipulating gene transcription by modifying enhancer activity.
Project description:Despite the development of diagnostic and advanced treatment strategies, the prognosis of patients with osteosarcoma remains poor. A limited understanding of the pathogenesis of osteosarcomas has impeded any improvement in patient outcomes over the past 4 decades. It is thus urgent to identify novel effective targets and treatment regimens for osteosarcoma patients. In this study we delineated the super-enhancer landscape in osteosarcoma cells on the basis of H3K27ac signal intensity by ChIP-Seq and found that super-enhancer-associated genes contribute to the malignant potential of osteosarcoma. THZ2, a novel small molecular inhibitor, shows a powerful anti-osteosarcoma ability through suppress super-enhancer-associated genes selectively. Utilizing the characteristics of super-enhancers in cancer cells, we identified 5 critical super-enhancer-associated oncogenes. With the comparative and retrospective analysis in large numbers of human specimens from patients, these 5 oncogenes were observed closely related with patient prognosis. Our findings determined that targeting super-enhancer-associated oncogenes with transcriptional inhibitor, THZ2, was a promising therapeutic strategy in osteosarcoma, and provided novel candidate targets for patients with osteosarcoma.
Project description:The tumor suppressor p53 has been studied extensively as a direct transcriptional activator of protein-coding genes. Recent studies, however, have shed light on novel regulatory functions of p53 within noncoding regions of the genome. Here, we use a systematic approach that integrates transcriptome-wide differential expression analysis, genome-wide p53 binding profiles, chromatin state maps, and additional genomic features to characterize the global regulatory roles of p53 in response to DNA damage in both human and mouse fibroblast models. In addition to known p53 targets, we identify many previously unappreciated mRNAs and long noncoding RNAs that are regulated by p53. Moreover, we find that p53 binding events occur predominantly within enhancer elements in both human and mouse systems. The ability to modulate enhancer activity offers an additional layer of complexity to the p53 network and greatly expands the diversity of genomic elements that are directly regulated by p53. Human and Mouse fibroblasts cultured in the presence or absence of doxorubicin followed by RNA-Seq (Human:2 cell lines, each condition in duplicate; Mouse:MEF cell line,each condition in triplicate) and p53 ChIP-Seq (Human:2 cell lines, input and IP for each; Mouse:MEF cell line, input and IP)
Project description:Hepatocellular carcinomas (HCC) exhibit distinct promoter hypermethylation patterns, but the epigenetic regulation and function of transcriptional enhancers remain unclear. Here, our affinity- and bisulfite-based whole-genome sequencing analyses reveal global enhancer hypomethylation in human HCCs. Integrative epigenomic characterization further pinpoints a recurrent hypomethylated enhancer of CCAAT/enhancer-binding protein-beta (C/EBPβ) which correlates with C/EBPβ over-expression and poorer prognosis of patients. Demethylation of C/EBPβ enhancer reactivates a self-reinforcing enhancer-target loop via direct transcriptional up-regulation of enhancer RNA. Conversely, deletion of this enhancer via CRISPR/Cas9 reduces C/EBPβ expression and its genome-wide co-occupancy with BRD4 at H3K27ac-marked enhancers and super-enhancers, leading to drastic suppression of driver oncogenes and abrogation of HCC tumorigenicity. Hepatitis B X protein transgenic mouse model of HCC recapitulates this paradigm, as C/ebpβ enhancer hypomethylation associates with oncogenic activation in early tumorigenesis. These results support a causal link between aberrant enhancer hypomethylation and C/EBPβ over-expression, thereby driving hepatocarcinogenesis through global transcriptional reprogramming.