BRD4 Research Articles

Introduction: Bromodomain-containing protein 4 (BRD4), a member of the BET family, functions as an epigenetic reader and plays a pivotal role in regulating transcriptional responses to inflammation and cellular stress. Emerging evidence implicates BRD4 in the pathogenesis of cerebral ischemia-reperfusion injury (IRI). Nitroxoline (NTX), a clinically approved antibiotic commonly used for urinary tract infections, has recently gained attention for its potent inhibitory activity against BRD4. However, the therapeutic potential of NTX in attenuating oxidative stress, neuroinflammation, and neuronal degeneration following cerebral IRI has not been studied. Hypothesis: We hypothesized that NTX may confer neuroprotection in a rat model of transient global cerebral IRI by inhibiting BRD4-mediated neuroinflammatory signaling and associated apoptotic pathways. Methods: Male Sprague-Dawley rats (180–200 g) were used to establish transient global cerebral IRI via bilateral common carotid artery occlusion (BCCAo) for 30 minutes followed by 7 days of reperfusion. Experimental groups included: normal control, sham-operated, BCCAo, and BCCAo treated with NTX at doses of 12.5, 25, and 50 mg/kg administered orally. Neurobehavioral assessments (locomotor activity, open-field performance, and rotarod test) were conducted on Days 1, 3, and 7. On Day 8, rats were euthanized, and brain tissues were collected for biochemical analyses (MDA, GSH, catalase, SOD) and expression of key molecular markers (BRD4, phosphorylated NFκB p65, Nrf2, Bcl-2, Bax, and caspase-3). Pro-inflammatory cytokines (TNF-α, IL-1β, IL-6) were quantified, and histological examinations (H&E and Nissl staining) were performed to assess neuronal integrity in hippocampal regions (CA1, CA3, dentate gyrus). Results: NTX treatment significantly improved behavioral outcomes and motor coordination in a dose-dependent manner compared to BCCAo group. Elevated levels of BRD4, p-NFκB p65, Bax, caspase-3, TNF-α, IL-1β, and IL-6 observed in BCCAo group were markedly reduced by NTX treatment. NTX also enhanced antioxidant defense, as evidenced by increased Nrf2 protein and improved redox balance. Histological analyses revealed reduced neuronal damage and preservation of hippocampal architecture in NTX-treated rats. Conclusion: This study demonstrates that NTX exerts neuroprotective effects against cerebral IRI, likely through BRD4 inhibition and downstream suppression of NFκB-driven inflammation and apoptosis.

Discovery of a potent BRD4 PROTAC and evaluation of its bioactivity in breast cancer cell lines.

Microfluidic-assisted preparation of ARV 825 and Osimertinib loaded liposomal formulation as a potential system for colorectal cancer therapy.

Discovering a potent and orally available imidazopyridine derivative as a BRD4 inhibitor: Enhancing antiproliferative activity against melanoma cells by mitigating P-gp substrate recognition.

Advances in BRD proteins in cardiovascular pathophysiology and therapy: A review.

Targeting the epigenetic regulator bromodomain-containing protein 4 by BRD4 siRNA lipoplexes and PFI-1 in psoriasis.

Targeting BRD4 in cancer therapy: From inhibitors and degraders to novel combination strategies and resistance mechanisms.

As a major contributor to cancer-associated deaths, advanced colorectal cancer (CRC) has a constrained range of effective treatment options. The short isoform of bromodomain-containing protein 4 (BRD4-S) has recently been implicated as a potential oncogenic driver; however, its regulatory mechanisms and functional role in CRC remain incompletely understood. BRD4-S expression, regulation, and function in CRC were investigated through bioinformatics analyses of the Cancer Genome Atlas (TCGA) datasets, in vitro studies using CRC cell lines (HT29, SW620), and in vivo xenograft models in nude mice. Experimental approaches included quantitative real-time PCR (qRT-PCR), Western blotting, co-immunoprecipitation, RNA immunoprecipitation, immunofluorescence, colony formation, Cell Counting Kit-8 (CCK-8), and scratch assays. Gene enrichment and interaction analyses were performed to identify relevant pathways and molecular partners. BRD4-S was markedly upregulated in CRC tissues and cell lines, and elevated BRD4-S expression correlated with poorer patient survival. Silencing BRD4-S, but not BRD4-L, significantly impaired CRC cell proliferation, migration, and tumor growth in vivo. Mechanistically, the RNA helicase DEAD-box helicase 27 (DDX27) interacted with Serine and Arginine Rich Splicing Factor 6 (SRSF6) to promote alternative splicing of BRD4 pre-mRNA toward the BRD4-S isoform. Inhibition of SRSF6 phosphorylation suppressed BRD4-S production and blocked activation of the mitogen-activated protein kinase (MAPK)/extracellular regulated protein kinases ERK signaling pathway, identified as a key downstream effector of BRD4-S. This study defines a novel DDX27-SRSF6-BRD4-S-MAPK/ERK signaling axis that drives CRC progression. These findings underscore the therapeutic potential of targeting BRD4 isoform switching and its regulatory splicing machinery in CRC.

Centromere protein F (CENP-F) is highly expressed in hepatocellular carcinoma (HCC), but the specific mechanism by which it regulates the occurrence and development of HCC is currently unclear. The activities of the super enhancer (SE) readers bromodomain-containing protein 4 (BRD4), cyclin-dependent kinase 1 (CDK1), cyclin-dependent kinase 2 (CDK2) and cyclin-dependent kinase 7 (CDK7) are significantly increased in HCC. This study explored the mechanism of CENP-F regulation in HCC through bioinformatics and cell and animal experiments. We found that the protein levels of CENP-F, CDK1, CDK2, CDK7 and BRD4 were significantly increased in HCC and that CENP-F was closely associated with CDK1, CDK2, CDK7 and BRD4. Downregulation of CENP-F led to a decrease in the protein levels of CENP-F, CDK1, CDK2, BRD4 and c-Myc and inhibited the proliferation of HepG2 and Hep3B cells. After overexpression of CENP-F, the above parameters returned to their previous levels. In addition, downregulation of BRD4 using siRNA and JQ1 led to decreases in the protein levels of BRD4 and c-Myc. CENP-F or BRD4 knockdown inhibited xenograft tumor growth in an in vivo HCC model. These findings suggested that CENP-F regulated the proliferation of HCC cells through the CENP-F-CDK1/CDK2-BRD4 axis. In conclusion, our study revealed a new mechanism by which CENP-F promotes HCC cell proliferation by the SE reader BRD4, suggesting that SEs play an essential role in mediating HCC treatment.Supplementary InformationThe online version contains supplementary material available at 10.1007/s12672-025-03785-5.

BRD4 ("Bromodomain-containing protein 4"), a recognized gene regulator, is an attractive target for therapeutic development, particularly for the management of neuroblastoma. An integrated pharmacoinformatic strategy for the development of new BRD4 inhibitors is examined in this research. Pharmacophores were used to digitally screen five databases, and the current study aims to determine the best binding modes by docking the screened hits to the BRD4 active site. Using the BRD4 protein co-crystal ligand (73B) (PDB ID: 4BJX) as a template, pharmacophore hypotheses were produced. Five databases were subjected to a pharmacophore-based virtual screening process, and 1089 hits that satisfied the screening requirements were selected for docking against the BRD4 receptor by using the SP module of the Glide tool. The top ten docked compounds with the highest binding affinities, ranging from - 9.623 to - 8.894kcal/mol, were selected. Further, the biological activity and ADMET analysis revealed that the selected compounds have values that fall in the acceptable range. The protein-ligand complexes' stability was verified by performing molecular dynamics (MD) simulations of the binding positions of the top two compounds against the BRD4 receptor. The stability and binding free energies of the compounds indicate that these compounds may function as lead compounds to affect the biological activity of BRD4 in the in vitro studies.

The role of bromodomain-containing protein 4 in the replication human papillomavirus, apoptosis, proliferation and migration of cervical cancer cells.

Radiotherapy (RT) combined with chemotherapy is the standard treatment for newly diagnosed glioblastoma (GBM). However, the limited RT efficacy and RT-related cancer resistance have spurred interest in radiosensitizing strategies for GBM. We aimed to explore the synergistic efficacy of the bromodomain-containing protein 4 (BRD4) inhibitor I-BET151 in combination with RT for GBM therapy. We found that BRD4 upregulation after RT was correlated with GBM radiosensitivity. I-BET151 sensitized GBM cells to RT by inhibiting cell proliferation and inducing cell apoptosis, thus prolonging survival in subcutaneous and orthotopic murine GL261 GBM mouse models. In vitro, I-BET151 sensitized GBM cells to RT by suppressing proliferation, inducing apoptosis, and increasing sustainable DNA damage. Mechanistically, integrated H3K27ac ChIP-sequencing and RNA-sequencing analysis identified type I collagen (COL1A1) as a key BRD4-dependent super-enhancer (SE)-driven target post-RT, which was also validated by ChIP‒qPCR. Moreover, RNA interference-mediated COL1A1 silencing reduced proliferation, increased apoptosis, and enhanced RT-induced DNA damage, underscoring its pivotal role in BRD4-mediated radioresistance. In conclusion, BRD4 contributes to extracellular matrix remodeling and radioresistance in a SE-driven COL1A1-dependent manner. Thus, targeting BRD4 is a rational strategy to augment the efficacy of RT for GBM treatment.

Chemo-metalloimmunotherapy is emerging as a promising strategy for cancer treatment by integrating chemotherapy-induced immunogenicity with metal ion-mediated immune activation. However, its efficacy is hampered by chemoresistance and immune escape driven by PD-L1 upregulation. Here, a multifunctional manganese-based metal-organic framework nanoplatform (Mn-CDDP-dBET6@CM) is reported that integrates metalloimmunotherapy, chemotherapy, and Proteolysis-targeting chimera (PROTAC) -mediated epigenetic modulation for enhanced cancer treatment. This system co-delivers Mn2+ to activate the stimulator of interferon genes (STING) pathway, cisplatin (CDDP) to induce nucleus DNA damage, and the bromodomain-containing protein 4 (BRD4) -targeting PROTAC dBET6 to promote mitochondrial DNA release and suppress PD-L1-mediated immune evasion. Coated with tumor cell membranes for homologous targeting and immune evasion, Mn-CDDP-dBET6@CM effectively induces cellular senescence, robust innate and adaptive immune activation, and tumor microenvironment remodeling. In vitro and in vivo studies demonstrate potent tumor growth inhibition, enhance dendritic cell maturation, and increase cytotoxic T cell infiltration. This nanoplatform offers a promising strategy to overcome chemoresistance and immunosuppression, providing a versatile approach for next-generation chemo-metalloimmunotherapy.

Our earlier research revealed a connection between microRNA-29b (miR-29b) and bromodomain-containing protein 4 (BRD4) and airway inflammation in chronic obstructive pulmonary disease (COPD). We examined their correlation with airway inflammation and dysbiosis in COPD individuals who had ceased smoking. Bacterial community composition and diversity were evaluated in bronchoalveolar lavage fluid (BALF) from COPD patients who had ceased smoking, and the expression of miR-29b/BRD4, interleukin (IL)-6 and IL-8 in bronchial brushings was measured. BEAS-2B cells were exposed to COPD BALF filtrate to establish an in vitro model. The expression levels of miR-29b, BRD4, IL-6, and IL-8 were subsequently assessed in these treated cells. The bacterial community composition in the lungs of individuals with COPD was different from that in the lungs of non-COPD subjects. In COPD patients, lung microbial diversity was significantly reduced, and this decline was correlated with both pulmonary function and airway inflammation. Additionally, the expression of miR-29b was lowered, whereas BRD4 expression was elevated in the lower airways of individuals with COPD. Both miR-29b and BRD4 were linked with pulmonary function, airway inflammation, and diversity indices. miR-29b regulated the production of inflammatory cytokines induced by BALF filtrate through its targeting of BRD4 in bronchial epithelial cells. Our findings indicate that airway inflammation is associated with airway dysbiosis in COPD patients after smoking cessation and that miR-29b/BRD4 are involved in dysbiosis-associated airway inflammation.

Although sorafenib (SF) is the standard first-line therapy for hepatocellular carcinoma (HCC), extended exposure frequently induces multipathway resistance driven by tumor hypoxia and an immunosuppressive microenvironment. Here we report a fluorinated Proteolysis TArgeting Chimeras (PROTAC)-sorafenib nanoassembly (FCP@SF/FPro) that boosts efficacy by degrading bromodomain-containing protein 4 (BRD4) and rewiring epigenetic programmes. This innovative system integrates fluorinated PROTAC targeting BRD4 (FPro) and sorafenib within a fluorinated poly(ethylene glycol)-conjugated poly(ethylenimine) (FCP) matrix, stabilized by fluorine-fluorine and hydrophobic interactions, ensuring high drug encapsulation efficiency and stability. By swiftly degrading BRD4, FCP@SF/FPro triggers apoptosis, down-regulates hypoxia-inducible factor 1-α (HIF-1α) to blunt hypoxia signaling, and relieves immunosuppression by lowering programmed death-ligand 1 (PD-L1) while boosting the M1/M2 tumor-associated macrophages (TAMs) ratio. The dual-payload platform suppresses tumors by coupling BRD4 degradation-driven epigenetic rewiring with immune-checkpoint relief. In vitro and in vivo, FCP@SF/FPro potently inhibits HCC growth and metastasis, highlighting its innovative potential as a fluorinated PROTAC-sorafenib combination therapy for drug-resistant HCC.

Bromodomain containing protein 4 (BRD4) and cancer therapy: A glimpse at dual-target drug development.

BRD2 promotes inflammation and lipid accumulation through the NF-κB pathway in alcoholic liver injury.

Achieving dual-target fluorescent probes for tracing and inhibiting BRD4/PLK1 in tumor cells and tissues synchronously.

The study aims to explore selective potential inhibitors for the homologous BD1/BD2 domains of bromodomain-containing protein 4 (BRD4) and uncover the binding mechanisms between these inhibitors and BD1/BD2. Given BRD4's role as an epigenetic regulator and its potential in treating triple-negative breast cancer (TNBC), overcoming the challenge of domain-specific inhibition due to the structural similarity of BD1 and BD2 is crucial. For comparison with experimental research, FL-411 was selected as a novel inhibitor for BD1/BD2. The AutoDock vina method was employed to screen potential lead compounds of BD1/BD2 from Traditional Chinese herbal medicines (TCMs) for nervous diseases. Molecular dynamics (MD) simulations were conducted to investigate the interaction mechanisms between BD1/BD2 and potential inhibitors (miltirone/FL-411). The analysis shows that the inhibitors stabilize the conformation of BD1/BD2 and enhance their hydrophobic and salt-bridge interactions. Notably, atomic interaction studies reveal that the oxygen atom of FL-411 binds with E85 of BD1, while the 1,1-Dimethylcyclohexane group of miltirone binds with H437 of BD2, indicating the selective characteristics of these potential inhibitors. The study reveals key structural determinants for BD1/BD2 selectivity, addressing a major challenge in BRD4-targeted drug design. MD simulations corroborate experimental data, validating the screening approach. Based on conformational characters of FL-411/miltirone and atomic interaction mechanism of BD1/BD2 and inhibitors, the potential inhibitors with a new skeleton and lower binding energy were generated with artificial intelligence drug discovery (AIDD) methods.

Targeting BRD4 bromodomains and beyond: exploring new therapeutic frontiers.