Aberrant super-enhancer landscape reveals core transcriptional regulatory circuitry in lung adenocarcinoma
ONCOGENESIS
Authors: Zhang, Te; Song, Xuming; Zhang, Zeyu; Mao, Qixing; Xia, Wenjie; Xu, Lin; Jiang, Feng; Dong, Gaochao
Abstract
Lung adenocarcinoma (LUAD) relies on dysregulated gene expression to sustain its infinite growth and progression. Emerging evidence indicates that aberrant transcriptional program results from core transcriptional regulatory circuitry (CRC) which is driven by super-enhancers (SEs). In this study, by integrating profiles of H3K27Ac chromatin immunoprecipitation sequencing (ChIP-seq) from normal adult lung and LUAD cell lines, we revealed that widespread alterations of the super-enhancer were presence during lung carcinogenesis. With SE-based modeling of regulatory circuits and assessments of transcription factor (TF) dependencies, we reconstructed an interconnected transcriptional regulation network formed by three master TFs, including ELF3, EHF, and TGIF1, all of which promoted each other's expression that confirmed by ChIP-qPCR and western blot. Loss-of function assay revealed that each of them is essential for LUAD cells survival, invasion and metastasis. Meanwhile, the rescue assay also illustrated the transacting transcriptional regulatory circuitry. In addition, the mRNA levels of ELF3, EHF, and TGIF1 were differentially expressed in LUAD tumors and peritumoral tissue. IHC of serial sections revealed that high expressions of CRC (ELF3/EHF/TGIF1-High) were closely associated with high proliferative activity in tumor tissue and poor prognosis on patients with LUAD. Finally, we used small molecular inhibitors to perturb the transcriptional circuitry, also exhibited a prominent anti-cancer effect in vitro. Our findings reveal the mechanism of the transcriptional dysregulation and addiction of LUAD.
Identification of ESE1 as a beta-Catenin Binding Protein
ANTICANCER RESEARCH
Authors: Yang, Xuyu; Lee, Seong-Ho
Abstract
Background/Aim: beta-Catenin regulates cell-cell adhesion and gene transcription and acts as a master switch that controls proliferation in several types of cancer. ESE1 is an epithelium-restricted transcription factor and its multiple domain structure predicts its interaction with other proteins with diverse cellular functions. Here, for the first time, we report that endogenous beta-catenin binds to and co-localizes with endogenous ESE1 in the cytoplasm. Materials and Methods: The binding sites were mapped to E26 transformation-specific (ETS) domain at carboxyl terminus of ESE1 and N-terminus of beta-catenin. Results: We found that C-terminus of ESE1 also binds to alpha-catenin and that ESE1/beta-catenin interaction was abrogated by knockdown of either beta-catenin or alpha-catenin. Conclusion: The data suggest that interactions between ESE1 and beta-/alpha-catenins might be a mechanism by which the ESE1 protein determines the beta-catenin function and tumorigenesis.