RESUMEN
Super-enhancers (SEs) are large clusters of enhancers located near the promoter and are necessary to determine the identity of cancer cells. The alterations of super-enhancers can cause dysregulation of the transcriptional program, which resulted in tumor cells being addicted to certain transcriptional programs. Tumor metastasis is the leading cause of death in cancer. Recently, SEs have been demonstrated to facilitate tumor metastasis by regulating lncRNA generation, tumor microenvironment, epithelial-mesenchymal transition, and cancer stem cells. In this review, the characteristics of SEs, the relationship between SEs and tumor metastasis, and inhibitors against SEs are summarized to provide a reference for the relevant mechanism of SEs regulating tumor metastasis and provide new perspectives for the diagnosis and treatment of patients with cancer metastasis.
RESUMEN
AIM:To investigate the effect of bromodomain-containing protein 4(BRD4)inhibitors on the via-bility and apoptosis of activated B cell-like diffuse large B-cell lymphoma(ABC-DLBCL)cells and the molecular mecha-nism. METHODS:The ABC-DLBCL cells were treated with BRD4 inhibitors JQ1 and I-BET-762,and Bruton tyrosine kinase(BTK)inhibitor ibrutinib. The viability and death of the cells were determined by CCK-8 assay and PI staining,re-spectively. The mRNA levels of BTK,phospholipase Cγ(PLCγ),LYN,SYK,interleukin-6(IL-6),MYC,protein ki-nase Cβ(PKCβ),mucosa-associated lymphoid tissue lymphoma translocation protein 1(MALT1),MYC and RELA were detected by real-time PCR. The protein levels of BTK,PLCγ,MYC and RELA were determined by Western blot. Super-enhancer around BTK gene was revealed by bioinformatics analysis. RESULTS:The ABC-DLBCL cells were sensitive to BRD4/super-enhancer inhibitors such as JQ1 and I-BET-762. Both JQ1 and I-BET-762 inhibited the chronic active B-cell receptor(BCR)/nuclear factorκB(NFκB)signaling through reducing the transcription of BTK,but they had minimal ef-fect on other components in BCR/NFκB signaling. Interestingly,there was no super-enhancer around BTK gene,and the inhibitory effect of JQ1 was likely due to disruption of BRD4 binding within BTK gene. Inhibition of BRD4 had synergic ef-fect with BTK inhibitor ibrutinib. Moreover,inhibition of BRD4 induced significant cell death in ibrutinib-resistant ABC-DLBCL cells. CONCLUSION:Inhibitors of BRD4 induce ABC-DLBCL cell death via blocking BCR/NFκB signaling and has synergic effect with BTK inhibitor. Inhibition of BRD4 might be a promising strategy for treatment of ABC-DLBCL,es-pecially ibrutinib-resistant ABC-DLBCL.
RESUMEN
Abnormal transcription of oncogenes driven by super enhancers was found to be critical for maintaining tumor cell identity.The expression of oncogenes can be effectively suppressed by inhibiting the key regulator that super enhancers regulate oncogene transcription.Bromodomain protein 4(BRD4)is a key protein to recognize the super enhancer regulatory elements, which can bind to acetylated histones or non-histones to regulate gene transcription.The abnormal expression of BRD4 is closely related to the malignant development of a variety of hematologic oncology.Targeting BRD4 can effectively control the malignant development of hematologic tumors.In recent years, BRD4-targeted drugs in hematologic oncology have received extensive attention, and they showed good antitumor effects either as a single drug or in combination with other drugs.In this paper, in order to provide a new understanding of the occurrence of leukemia and treatment of hematologic oncology, the biological functions of BRD4 as well as the molecular drugs targeting BRD4 are reviewed.