WDR5 promotes the proliferation of lung adenocarcinoma by inducing SOX9 expression

Aim: WDR5 is a coactivator of transcription factor which promotes the progression of several cancer types, but its function in lung adenocarcinoma (AC) is unknown. Materials & methods: We detected WDR5 expression in lung AC with quantitative real-time polymerase chain reaction and immunohistochemistry. Results: WDR5 was significantly overexpressed in ACs compared with normal lung tissues. Moreover, WDR5 was an independent prognostic biomarker of lung AC. With clinical analyzation and in vitro experiments, we proved that SOX9 was a downstream effector of WDR5 in promoting A549 proliferation, and that SOX9 was also an unfavorable prognostic biomarker of lung AC. Conclusion: WDR5 and SOX9 are both prognostic biomarkers predicting poor outcome of lung AC. WDR5 could promote proliferation of lung AC by elevating SOX9 expression.

WDR5 promotes the tumorigenesis of oral squamous cell carcinoma via CARM1/β-catenin axis

Oral squamous cell carcinoma (OSCC) is a malignancy all over the world. WD repeat domain 5 (WDR5) is involved in cancer progression. In addition, it was reported that WDR5 is upregulated in head and neck cancer, while its role in OSCC is unknown. First, the expression of WDR5 in oral cancer tissues and cells was examined by qRT-PCR, IHF and western blot. CCK-8 assay was performed to test the cell viability. Cell migration was assessed by transwell assay. Knocking down WDR5 or CARM1 in oral cancer cells to detect its function on cancer growth, WDR5 and CARM1 were significantly upregulated in OSCC. Silencing WDR5 suppressed OSCC cell viability and migration. CARM1 level in OSCC cells was significantly inhibited by WDR5 downregulation, and CARM1 elevation could rescue the effect of WDR5 knockdown on tumorigenesis of OSCC. Moreover, silencing of WDR5 notably inactivated β-catenin signaling pathway, while this phenomenon was restored by CARM1 overexpression. Silencing of WDR5 attenuated the tumorigenesis of OSCC via CARM1/β-catenin axis. Thus, WDR5 might be a target for OSCC treatment.

BAG3 epigenetically regulates GALNT10 expression via WDR5 and facilitates the stem cell-like properties of platin-resistant ovarian cancer cells

Ovarian cancer is the most lethal gynecologic malignant cancer, frequently due to its late diagnosis and high recurrence. Cancer stem cells (CSCs) from different malignancies including ovarian cancer have been linked to chemotherapy resistance and poor prognosis. Therefore, identifying the molecular mechanisms mediating therapy resistance is urgent to finding novel targets for therapy-resistant tumors. Aberrant O-glycosylation ascribed to subtle alteration of GALNT family members during malignant transformation facilitate metastasis in various cancers. The current study demonstrated that BAG3 was upregulated in platin-resistant ovarian cancer tissues and cells, and high BAG3 predicted dismal disease-free survival of patients with ovarian cancer. In addition, the current study showed that BAG3 facilitated CSC-like properties of ovarian cancer cells via regulation of GALTN10. In a term of mechanism, BAG3 epigenetically regulated GALNT10 transactivation via histone H3 lysine 4 (H3K4) presenter WDR5. We demonstrated that WDR5 increased H3K4 trimethylation (H3K4me3) modification at the promoter regions of GALNT10, facilitating recruitment of transcription factor ZBTB2 to the GALNT10 promoter. Collectively, our study uncovers an epigenetic upregulation of GALNT10 by BAG3 via WDR5 to facilitate CSCs of platin-resistant ovarian cancers, providing additional information for further identification of attractive targets with therapeutic significance in platin-resistant ovarian cancer.

WD repeat domain 5 promotes chemoresistance and Programmed Death-Ligand 1 expression in prostate cancer

Purpose: Advanced prostate cancer (PCa) has limited treatment regimens and shows low response to chemotherapy and immunotherapy, leading to poor prognosis. Histone modification is a vital mechanism of gene expression and a promising therapy target. In this study, we characterized WD repeat domain 5 (WDR5), a regulator of histone modification, and explored its potential therapeutic value in PCa. Experimental Design: We characterized specific regulators of histone modification, based on TCGA data. The expression and clinical features of WDR5 were analyzed in two dependent cohorts. The functional role of WDR5 was further investigated with siRNA and OICR-9429, a small molecular antagonist of WDR5, in vitro and in vivo. The mechanism of WDR5 was explored by RNA-sequencing and chromatin immunoprecipitation (ChIP). Results: WDR5 was overexpressed in PCa and associated with advanced clinicopathological features, and predicted poor prognosis. Both inhibition of WDR5 by siRNA and OICR-9429 could reduce proliferation, and increase apoptosis and chemosensitivity to cisplatin in vitro and in vivo. Interestingly, targeting WDR5 by siRNA and OICR-9429 could block IFN-γ-induced PD-L1 expression in PCa cells. Mechanistically, we clarified that some cell cycle, anti-apoptosis, DNA repair and immune related genes, including AURKA, CCNB1, E2F1, PLK1, BIRC5, XRCC2 and PD-L1, were directly regulated by WDR5 and OICR-9429 in H3K4me3 and c-Myc dependent manner. Conclusions: These data revealed that targeting WDR5 suppressed proliferation, enhanced apoptosis, chemosensitivity to cisplatin and immunotherapy in PCa. Therefore, our findings provide insight into OICR-9429 is a multi-potency and promising therapy drug, which improves the antitumor effect of cisplatin or immunotherapy in PCa.

Phage-Display Based Discovery and Characterization of Peptide Ligands against WDR5

WD40 is a ubiquitous domain presented in at least 361 human proteins and acts as scaffold to form protein complexes. Among them, WDR5 protein is an important mediator in several protein complexes to exert its functions in histone modification and chromatin remodeling. Therefore, it was considered as a promising epigenetic target involving in anti-cancer drug development. In view of the protein-protein interaction nature of WDR5, we initialized a campaign to discover new peptide-mimic inhibitors of WDR5. In current study, we utilized the phage display technique and screened with a disulfide-based cyclic peptide phage library. Five rounds of biopanning were performed and isolated clones were sequenced. By analyzing the sequences, total five peptides were synthesized for binding assay. The four peptides are shown to have the moderate binding affinity. Finally, the detailed binding interactions were revealed by solving a WDR5-peptide cocrystal structure.

WDR5 facilitates EMT and metastasis of CCA by increasing HIF-1α accumulation in Myc-dependent and independent pathways

Cholangiocarcinoma (CCA) is a highly aggressive malignancy with extremely poor prognoses. The oncogenic role and prognostic value of c-Myc in CCA is not well elucidated. WD repeat domain 5 (WDR5) is a critical regulatory factor directly interacting with c-Myc to regulate c-Myc recruitment at chromosomal locations, but the interaction of WDR5 and c-Myc in CCA was uncovered. In our study, we detected WDR5 and c-Myc expression in all CCA types, including intrahepatic (iCCA), perihilar (pCCA), and distal (dCCA) CCA, and evaluated their prognostic significance. Consequently, we demonstrated that WDR5 was significantly correlated with poor prognosis of CCA and that WDR5 and c-Myc co-expression was a more sensitive prognostic factor. With in vitro and in vivo experiments and bioinformatics, we showed that WDR5 interacted with the Myc box IIIb (MBIIIb) motif of c-Myc and facilitated Myc-induced HIF1A transcription, thereby promoting the epithelial-mesenchymal transition (EMT), invasion, and metastasis of CCA. Moreover, WDR5 enhanced hypoxia-inducible factor 1 subunit α (HIF-1α) accumulation by binding with histone deacetylase 2 (HDAC2) and increasing histone 3 lysine 4 acetylation (H3K4ac) deacetylation of the prolyl hydroxylase domain protein 2 (PHD2) promoter, resulting in the attenuation of chromatin opening and PHD2 expression, and eventually leading to HIF-1α stabilization and accumulation. In conclusion, WDR5 facilitated EMT and metastasis of CCA by increasing HIF-1α accumulation in a Myc-dependent pathway to promote HIF-1α transcription and a Myc-independent pathway to stabilize HIF-1α.

p53 Integrates Temporal WDR5 Inputs during Neuroectoderm and Mesoderm Differentiation of Mouse Embryonic Stem Cells

How ubiquitous transcription factors (TFs) coordinate temporal inputs from broadly expressed epigenetic factors to control cell fate remains poorly understood. Here, we uncover a molecular relationship between p53, an abundant embryonic TF, and WDR5, an essential member of the MLL chromatin modifying complex, that regulates mouse embryonic stem cell fate. Wild-type Wdr5 or transient Wdr5 knockout promotes a distinct pattern of global chromatin accessibility and spurs neuroectodermal differentiation through an RbBP5-dependent process in which WDR5 binds to, and activates transcription of, neural genes. Wdr5 rescue after its prolonged inhibition targets WDR5 to mesoderm lineage-specifying genes, stimulating differentiation toward mesoderm fates in a p53-dependent fashion. Finally, we identify a direct interaction between WDR5 and p53 that enables their co-recruitment to, and regulation of, genes known to control cell proliferation and fate. Our results unmask p53-dependent mechanisms that temporally integrate epigenetic WDR5 inputs to drive neuroectoderm and mesoderm differentiation from pluripotent cells.

How ubiquitous chromatin-associated proteins and transcription factors (TFs) regulate cell fate determination is poorly understood. Li et al. show that regulation of the broadly expressed TF p53 by the chromatin-associated protein WDR5 is required for neuroectoderm versus mesoderm lineage determination in mouse embryonic stem cells (ESCs).

Impact of WIN site inhibitor on the WDR5 interactome

The chromatin-associated protein WDR5 is a promising pharmacological target in cancer, with most drug discovery efforts directed against an arginine-binding cavity in WDR5 called the WIN site. Despite a clear expectation that WIN site inhibitors will alter the repertoire of WDR5 interaction partners, their impact on the WDR5 interactome remains unknown. Here, we use quantitative proteomics to delineate how the WDR5 interactome is changed by WIN site inhibition. We show that the WIN site inhibitor alters the interaction of WDR5 with dozens of proteins, including those linked to phosphatidylinositol 3-kinase (PI3K) signaling. As proof of concept, we demonstrate that the master kinase PDPK1 is a bona fide high-affinity WIN site binding protein that engages WDR5 to modulate transcription of genes expressed in the G2 phase of the cell cycle. This dataset expands our understanding of WDR5 and serves as a resource for deciphering the action of WIN site inhibitors.

The Development of Inhibitors Targeting the Mixed Lineage Leukemia 1 (MLL1)-WD Repeat Domain 5 Protein (WDR5) Protein- Protein Interaction

Mixed Lineage Leukemia 1 (MLL1), an important member of Histone Methyltransferases (HMT) family, is capable of catalyzing mono-, di-, and trimethylation of Histone 3 lysine 4 (H3K4). The optimal catalytic activity of MLL1 requires the formation of a core complex consisting of MLL1, WDR5, RbBP5, and ASH2L. The Protein-Protein Interaction (PPI) between WDR5 and MLL1 plays an important role in abnormal gene expression during tumorigenesis, and disturbing this interaction may have a potential for the treatment of leukemia harboring MLL1 fusion proteins. In this review, we will summarize recent progress in the development of inhibitors targeting MLL1- WDR5 interaction.

WDR5 Promotes Proliferation and Correlates with Poor Prognosis in Oesophageal Squamous Cell Carcinoma

Background

The WD40 protein family member WD repeat domain 5 (WDR5) plays significant roles in the tumorigenesis and development of multiple organ tumours. However, the correlation between WDR5 expression and oesophageal squamous cell carcinoma (ESCC) has not been elucidated.

Methods

WDR5 mRNA expression data were acquired from The Cancer Genome Atlas (TCGA) database, and the expression and prognostic potential of WDR5 were assessed by immunohistochemistry (IHC) and Western blot. The cell counting kit-8 (CCK-8), colony formation assay and cell cycle evaluation were performed to verify the WDR5 function in vitro. The xenograft model was used to verify WDR5 function in vivo.

Results

The mRNA and protein expression levels of WDR5 were significantly upregulated in ESCC tissues compared with expression in adjacent normal tissues. Kaplan-Meier analysis showed that high WDR5 expression in ESCC patients was associated with poor overall survival (P=0.004). Multivariate analysis revealed that WDR5 overexpression emerged as an independent predictor of poor overall survival (P=0.013) in ESCC. The in vitro and in vivo experiments revealed that downregulation of WDR5 expression blocked cell proliferation of ESCC. Mechanistically, we found that WDR5 may influence ESCC proliferation by targeting the PI3K/AKT/mTOR signalling pathway.

Conclusion

Our data demonstrate that overexpression of WDR5 was associated with poor prognosis in patients with ESCC and that WDR5 may act as a potential novel prognostic biomarker for ESCC.

TrxG Complex Catalytic and Non-catalytic Activity Play Distinct Roles in Pancreas Progenitor Specification and Differentiation

Appropriate regulation of genes that coordinate pancreas progenitor proliferation and differentiation is required for pancreas development. Here, we explore the role of H3K4 methylation and the Trithorax group (TrxG) complexes in mediating gene expression during pancreas development. Disruption of TrxG complex assembly, but not catalytic activity, prevented endocrine cell differentiation in pancreas progenitor spheroids. In vivo loss of TrxG catalytic activity in PDX1⁺ cells increased apoptosis and the fraction of progenitors in the G1 phase of the cell cycle. Pancreas progenitors were reallocated to the acinar lineage, primarily at the expense of NEUROG3⁺ endocrine progenitors. Later in development, acinar and endocrine cell numbers were decreased, and increased gene expression variance and reduced terminal marker activation in acinar cells led to their incomplete differentiation. These findings demonstrate that TrxG co-activator activity is required for gene induction, whereas TrxG catalytic activity and H3K4 methylation help maintain transcriptional stability.

WD Repeat Domain 5 Promotes Invasion, Metastasis and Tumor Growth in Glioma Through Up-Regulated Zinc Finger E-Box Binding Homeobox 1 Expression

Background

Glioma is one of the important diseases that threaten human survival in today’s society. WD repeat domain 5 (WDR5) belongs to the components of the lysine methyltransferase complex. WDR5 is involved in gene transcription regulation, cell senescence, cancer and other biological events through methylation modification. However, its expression and function in glioma are still unclear.

Materials and Methods

The expression of WDR5 was observed in glioma cells, and then a glioma cell line SW1783 knocked down WDR5 was established. The effects of the decrease of WDR5 expression on proliferation, migration, invasion and EMT of glioma cells were detected, respectively. The downstream regulators of WDR5 were identified by gene expression profiling technology, and the possible molecular mechanisms were identified.

Results

In this study, we found that WDR5 could promote glioma cell’s proliferation, migration, invasion and tumor metastasis. In glioma, especially in metastatic glioma tissues, WDR5 levels were significantly increased, the higher expression level could also cause a significant reduction in overall survival of glioma patients. Second, the ability of cells’ proliferation, migration, invasion and tumor metastasis was significantly reduced in WDR5 knockdown cell lines. We also found a significant change in the expression level of epithelial and mesenchymal markers in WDR5 knockdown cell lines. Furthermore, we found that knockdown of WDR5 could inhibit the expression of zinc finger E-box binding homeobox 1 (ZEB1), and knockdown of ZEB1 could inhibit invasion, migration and epithelial–mesenchymal transformation (EMT) in WDR5 over-expression cell line. We also found that WDR5 may regulate ZEB1’s expression through H3K4me3.

Conclusion

In summary, in this study, we have studied the relationship between WDR5 and glioma, and found that WDR5’s expression is positively correlated with the proliferation, migration, and invasion of glioma cells, which will help find the potential therapeutic target for glioma patients.

Epigenetic regulation of epithelial-mesenchymal transition: focusing on hypoxia and TGF-β signaling

Epithelial-mesenchymal transition (EMT) is an important process triggered during cancer metastasis. Regulation of EMT is mostly initiated by outside signalling, including TGF-β, growth factors, Notch ligand, Wnt, and hypoxia. Many signalling pathways have been delineated to explain the molecular mechanisms of EMT. In this review, we will focus on the epigenetic regulation of two critical EMT signalling pathways: hypoxia and TGF-β. For hypoxia, hypoxia-induced EMT is mediated by the interplay between chromatin modifiers histone deacetylase 3 (HDAC3) and WDR5 coupled with the presence of histone 3 lysine 4 acetylation (H3K4Ac) mark that labels the promoter regions of various traditional EMT marker genes (e.g. CDH1, VIM). Recently identified new hypoxia-induced EMT markers belong to transcription factors (e.g. SMO, GLI1) that mediate EMT themselves. For TGF-β-induced ΕΜΤ, global chromatin changes, removal of a histone variant (H2A.Z), and new chromatin modifiers (e.g. UTX, Rad21, PRMT5, RbBP5, etc) are identified to be crucial for the regulation of both EMT transcription factors (EMT-TFs) and EMT markers (EMT-Ms). The epigenetic mechanisms utilized in these two pathways may serve as good model systems for other signalling pathways and also provide new potential therapeutic targets.

LncRNA HOTTIP enhances human osteogenic BMSCs differentiation via interaction with WDR5 and activation of Wnt/β-catenin signalling pathway

To uncover the underlying molecular mechanism of long non-coding RNA in the osteogenic differentiation process of bone marrow mesenchymal stem cells (BMSCs), HOXA transcript at the distal tip (HOTTIP) was selected by using a lncRNA microarray assay. Results showed that HOTTIP was significantly upregulated during osteogenic differentiation of human BMSCs. Downregulation of HOTTIP by shRNA inhibited the osteogenic differentiation of BMSCs. Overexpression of HOTTIP by lentiviral vector promoted human BMSCs osteogenic differentiation by increasing the transcription of β-catenin. RIP assay and RNA pulldown assay confirmed the interaction between HOTTIP and WDR5, a transcription factor binding to the promoter of β-catenin. The interaction promoted the translocation of WDR5 into the nucleus and increased the transcription of β-catenin. Implanted HOTTIP-overexpressing BMSCs increased ectopic bone formation in nude mice. HOTTIP is a conservative long noncoding RNA that is essential for osteogenic differentiation of BMSC. HOTTIP enhances osteogenic differentiation via interaction with WDR5 and up-regulation of β-catenin gene expression, therefore activating Wnt/β-catenin signalling pathway.

Targeting MYC through WDR5

The oncoprotein transcription factor MYC is overexpressed in most cancers and is responsible for hundreds of thousands of cancer deaths worldwide every year. MYC is also a highly validated - but currently undruggable - anti-cancer target. We recently showed that breaking the interaction of MYC with its chromatin co-factor WD repeat-containing protein 5 (WDR5) promotes tumor regression in mouse xenografts, laying the foundation for a new strategy to inhibit MYC in the clinic.

WDR5 inhibition halts metastasis dissemination by repressing the mesenchymal phenotype of breast cancer cells

Background

Development of metastases and drug resistance are still a challenge for a successful systemic treatment in breast cancer (BC) patients. One of the mechanisms that confer metastatic properties to the cell relies in the epithelial-to-mesenchymal transition (EMT). Moreover, both EMT and metastasis are partly modulated through epigenetic mechanisms, by repression or induction of specific related genes.

Methods

We applied shRNAs and drug targeting approaches in BC cell lines and metastatic patient-derived xenograft (PDX) models to inhibit WDR5, the core subunit of histone H3 K4 methyltransferase complexes, and evaluate its role in metastasis regulation.

Result

We report that WDR5 is crucial in regulating tumorigenesis and metastasis spreading during BC progression. In particular, WDR5 loss reduces the metastatic properties of the cells by reverting the mesenchymal phenotype of triple negative- and luminal B-derived cells, thus inducing an epithelial trait. We also suggest that this regulation is mediated by TGFβ1, implying a prominent role of WDR5 in driving EMT through TGFβ1 activation. Moreover, such EMT reversion can be induced by drug targeting of WDR5 as well, leading to BC cell sensitization to chemotherapy and enhancement of paclitaxel-dependent effects.

Conclusions

We suggest that WDR5 inhibition could be a promising pharmacologic approach to reduce cell migration, revert EMT, and block metastasis formation in BC, thus overcoming resistance to standard treatments.

LncRNA SATB2-AS1 inhibits tumor metastasis and affects the tumor immune cell microenvironment in colorectal cancer by regulating SATB2

Background

Emerging studies suggest that long non-coding RNAs (lncRNAs) play crucial roles in colorectal cancer (CRC). Here, we report a lncRNA, SATB2-AS1, which is specifically expressed in colorectal tissue and is significantly reduced in CRC. We systematically elucidated its functions and possible molecular mechanisms in CRC.

Methods

LncRNA expression in CRC was analyzed by RNA-sequencing and RNA microarrays. The expression level of SATB2-AS1 in tissues was determined by quantitative reverse transcription polymerase chain reaction (qRT-PCR) and in situ hybridization (ISH). The functional role of SATB2-AS1 in CRC was investigated by a series of in vivo and in vitro assays. RNA pull-down, RNA immunoprecipitation (RIP), chromatin immunoprecipitation (ChIP), chromatin isolation by RNA purification (ChIRP), Bisulfite Sequencing PCR (BSP) and bioinformatics analysis were utilized to explore the potential mechanisms of SATB2-AS1.

Results

SATB2-AS1 is specifically expressed in colorectal tissues and downregulated in CRC. Survival analysis indicates that decreased SATB2-AS1 expression is associated with poor survival. Functional experiments and bioinformatics analysis revealed that SATB2-AS1 inhibits CRC cell metastasis and regulates TH1-type chemokines expression and immune cell density in CRC. Mechanistically, SATB2-AS1 directly binds to WDR5 and GADD45A, cis-activating SATB2 (Special AT-rich binding protein 2) transcription via mediating histone H3 lysine 4 tri-methylation (H3K4me3) deposition and DNA demethylation of the promoter region of SATB2.

Conclusions

This study reveals the functions of SATB2-AS1 in CRC tumorigenesis and progression, suggesting new biomarkers and therapeutic targets in CRC.

Electronic supplementary material

The online version of this article (10.1186/s12943-019-1063-6) contains supplementary material, which is available to authorized users.

Inhibition of the H3K4 methyltransferase MLL1/WDR5 complex attenuates renal senescence in ischemia reperfusion mice by reduction of p16INK4a

Renal function declines with aging and is pathologically characterized by chronic inflammation and fibrosis. Renal senescence is induced not only by aging but also by various stimuli, including ischemia reperfusion injury. Recently, the accumulation of p16^INK4a-positive cells in the kidney has been considered a molecular feature of renal senescence, with the p16^INK4a gene reportedly regulated by mixed-lineage leukemia 1 (MLL1)/WD-40 repeat protein 5 (WDR5)-mediated histone 3 lysine 4 trimethylation (H3K4me3). Here, we determined whether inhibition of MLL1/WDR5 activity attenuates renal senescence, inflammation, and fibrosis in mice with ischemia reperfusion injury and in cultured rat renal fibroblasts. MM-102 or OICR-9429, both MLL1/WDR5 protein-protein interaction inhibitors, and small interfering RNA (siRNA) for MLL1 or WDR5 suppressed the expression of p16^INK4a in mice with ischemia reperfusion injury, accompanied by downregulation of H3K4me3 expression. MM-102 attenuated renal fibrosis and inflammation in the kidney of mice with ischemia reperfusion injury. Moreover, in vitro study showed that transforming growth factor-β1 induced the expression of MLL1, WDR5, H3K4me3, and p16^INK4a. Finally, chromatin immunoprecipitation identified the p16^INK4a promoter at an H3K4me3 site in renal fibroblasts. Thus, our findings show that H3K4me3 inhibition ameliorates ischemia reperfusion-induced renal senescence along with fibrosis and inflammation.

Targeting WDR5: A WINning Anti-Cancer Strategy?

WDR5 is a component of multiple epigenetic regulatory complexes, including the mixed lineage leukemia (MLL)/SET complexes that deposit histone H3 lysine 4 methylation. Inhibitors of an arginine-binding cavity in WDR5, known as the WDR5-interaction (WIN) site, have been proposed to selectively kill MLL-rearranged malignancies via an epigenetic mechanism. We discovered potent WIN site inhibitors and found that they kill MLL cancer cells not through changes in histone methylation, but by displacing WDR5 from chromatin at protein synthesis genes, choking the translational capacity of these cells, and inducing death via a nucleolar stress response. The mechanism of action of WIN site inhibitors reveals new aspects of WDR5 function and forecasts broad therapeutic utility as anti-cancer agents.

Lnc-C/EBPβ Modulates Differentiation of MDSCs Through Downregulating IL4i1 With C/EBPβ LIP and WDR5

Myeloid-derived suppressor cells (MDSCs), which play an important role in tumor and inflammatory diseases, are divided into two subsets CD11b⁺Ly6C^hiLy6G^- monocytic MDSC (Mo-MDSC) and CD11b⁺Ly6C^low/negLy6G⁺ polymorphonuclear MDSC (PMN-MDSC) with different immunosuppressive function. However, it is poorly understood the mechanism(s) to control differentiation of Mo-MDSCs and PMN-MDSCs. Here, we found that lnc-C/EBPβ may promote PMN-MDSC but impede differentiation of Mo-MDSCs in vitro and in vivo. We demonstrated that lnc-C/EBPβ mediated differentiation of MDSCs was through downregulating multiple transcripts such as IL4il. Lnc-C/EBPβ not only bound to C/EBPβ isoform LIP to inhibit the activation of C/EBPβ but also interacted with WDR5 to interrupt the enrichment of H3K4me3 mark on the promoter region of IL4i1. Data also imply that conserved homo lnc-C/EBPβ has a similar function with mouse lnc-C/EBPβ. Since MDSC subsets exert different suppressive function, lnc-C/EBPβ may be acted as a potential therapeutic target for inflammatory and tumor-associated diseases.

WDR5, BRCA1, and BARD1 Co-regulate the DNA Damage Response and Modulate the Mesenchymal-to-Epithelial Transition during Early Reprogramming

Differentiated cells are epigenetically stable, but can be reprogrammed to pluripotency by expression of the OSKM transcription factors. Despite significant effort, relatively little is known about the cellular requirements for reprogramming and how they affect the properties of induced pluripotent stem cells. We have performed high-content screening with small interfering RNAs targeting 300 chromatin-associated factors and extracted colony-level quantitative features. This revealed five morphological phenotypes in early reprogramming, including one displaying large round colonies exhibiting an early block of reprogramming. Using RNA sequencing, we identified transcriptional changes associated with these phenotypes. Furthermore, double knockdown epistasis experiments revealed that BRCA1, BARD1, and WDR5 functionally interact and are required for the DNA damage response. In addition, the mesenchymal-to-epithelial transition is affected in Brca1, Bard1, and Wdr5 knockdowns. Our data provide a resource of chromatin-associated factors in early reprogramming and underline colony morphology as an important high-dimensional readout for reprogramming quality.

Displacement of WDR5 from Chromatin by a WIN Site Inhibitor with Picomolar Affinity

The chromatin-associated protein WDR5 is a promising target for pharmacological inhibition in cancer. Drug discovery efforts center on the blockade of the "WIN site" of WDR5, a well-defined pocket that is amenable to small molecule inhibition. Various cancer contexts have been proposed to be targets for WIN site inhibitors, but a lack of understanding of WDR5 target genes and of the primary effects of WIN site inhibitors hampers their utility. Here, by the discovery of potent WIN site inhibitors, we demonstrate that the WIN site links WDR5 to chromatin at a small cohort of loci, including a specific subset of ribosome protein genes. WIN site inhibitors rapidly displace WDR5 from chromatin and decrease the expression of associated genes, causing translational inhibition, nucleolar stress, and p53 induction. Our studies define a mode by which WDR5 engages chromatin and forecast that WIN site blockade could have utility against multiple cancer types.

The Histone H3 Lysine 4 Presenter WDR5 as an Oncogenic Protein and Novel Epigenetic Target in Cancer

The histone H3 lysine 4 (H3K4) presenter WDR5 forms protein complexes with H3K4 methyltransferases MLL1-MLL4 and binding partner proteins including RBBP5, ASH2L, and DPY30, and plays a key role in histone H3K4 trimethylation, chromatin remodeling, transcriptional activation of target genes, normal biology, and diseases such as MLL-rearranged leukemia. By forming protein complexes with other proteins such as Myc, WDR5 induces transcriptional activation of key oncogenes, tumor cell cycle progression, DNA replication, cell proliferation, survival, tumor initiation, progression, invasion, and metastasis of cancer of a variety of organ origins. Several small molecule MLL/WDR5 protein-protein interaction inhibitors, such as MM-401, MM-589, WDR5-0103, Piribedil, and OICR-9429, have been confirmed to reduce H3K4 trimethylation, oncogenic gene expression, cell cycle progression, cancer cell proliferation, survival and resistance to chemotherapy without general toxicity to normal cells. Derivatives of the MLL/WDR5 interaction inhibitors with improved pharmacokinetic properties and in vivo bioavailability are expected to have the potential to be trialed in cancer patients.

The long noncoding RNA GAS8-AS1 suppresses hepatocarcinogenesis by epigenetically activating the tumor suppressor GAS8

Long noncoding RNAs (lncRNAs) are vital players in cancers, including hepatocellular carcinoma (HCC). We previously identified an lncRNA, GAS8-AS1, that is located in intron 2 of GAS8 However, its involvement in HCC is still largely unknown. In this study, we report that both GAS8-AS1 and its host gene GAS8 act as HCC tumor suppressors. We found that expression of GAS8-AS1 or GAS8 is significantly decreased in HCC tissues and is associated with a poor prognosis among HCC patients. Interestingly, lncRNA GAS8-AS1 could promote GAS8 transcription. We detected a CpG island in the GAS8 promoter, but lncRNA GAS8-AS1 did not affect DNA methylation at this GAS8 promoter site. Moreover, we identified two GAS8-AS1-interacting proteins, mixed-lineage leukemia 1 (MLL1), a histone 3 Lys-4 (H3K4) methyltransferase, and its partner WD-40 repeat protein 5 (WDR5). RNA pulldown, ChIP, and RNA immunoprecipitation assays revealed that GAS8-AS1 is required for maintaining the GAS8 promoter in an open chromatin state by recruiting the MLL1/WDR5 complex and for enhancing RNA polymerase II activity and GAS8 transcription. Of note, GAS8-AS1-dependent GAS8 hyperactivation inhibited malignant transformation of hepatocytes. Our results provide important insights into how lncRNA GAS8-AS1 suppresses HCC development and suggest potential strategies for treating patients with liver cancer.

WDR5 modulates cell motility and morphology and controls nuclear changes induced by a 3D environment

Cell migration through extracellular matrices requires nuclear deformation, which depends on nuclear stiffness. In turn, chromatin structure contributes to nuclear stiffness, but the mechanosensing pathways regulating chromatin during cell migration remain unclear. Here, we demonstrate that WD repeat domain 5 (WDR5), an essential component of H3K4 methyltransferase complexes, regulates cell polarity, nuclear deformability, and migration of lymphocytes in vitro and in vivo, independent of transcriptional activity, suggesting nongenomic functions for WDR5. Similarly, depletion of RbBP5 (another H3K4 methyltransferase subunit) promotes similar defects. We reveal that a 3D environment increases the H3K4 methylation dependent on WDR5 and results in a globally less compacted chromatin conformation. Further, using atomic force microscopy, nuclear particle tracking, and nuclear swelling experiments, we detect changes in nuclear mechanics that accompany the epigenetic changes induced in 3D conditions. Indeed, nuclei from cells in 3D environments were softer, and thereby more deformable, compared with cells in suspension or cultured in 2D conditions, again dependent on WDR5. Dissecting the underlying mechanism, we determined that actomyosin contractility, through the phosphorylation of myosin by MLCK (myosin light chain kinase), controls the interaction of WDR5 with other components of the methyltransferase complex, which in turn up-regulates H3K4 methylation activation in 3D conditions. Taken together, our findings reveal a nongenomic function for WDR5 in regulating H3K4 methylation induced by 3D environments, physical properties of the nucleus, cell polarity, and cell migratory capacity.