Project description:The Asp-Glu-Ala-Asp (DEAD)-box RNA binding protein, DDX5, is ubiquitously expressed in many cell types, yet its role in RNA metabolism and its downstream function in vivo has not been fully elucidated. In the intestine, DDX5 is highly expressed in the intestinal epithelial cell (IECs) and contributes to tumorigenesis. Here, we used a conditional mouse lines where DDX5 is knocked out in IECs upon Tamoxifen administration to uncover mechanisms underlying DDX5 functions in colon tumors.
Project description:Fra-1, a member of the activator protein 1 (AP-1) family, is overexpressed in triple-negative breast cancer (TNBC) and plays crucial roles in tumor growth. Here we report the identification of 118 proteins interacting with endogenous chromatin-bound Fra-1 in TNBC cells, highlighting DDX5 as the most enriched Fra-1-interacting protein. DDX5, a previously unrecognized protein in the Fra-1 transcriptional network, shows extensive overlap with Fra-1 cistrome and transcriptome that are highly associated with the TNBC cell growth. We provide evidence that DDX5 expression enhances Fra-1 transcriptional activity and potentiates Fra-1-driven cell proliferation. Furthermore, we show that the DDX5 target gene signature predicts poor clinical outcome in breast cancer patients. DDX5 protein level was higher in triple-negative basal-like tumors than in non-basal-like tumors, including luminal A, luminal B, and HER2-enriched subtypes. Collectively, by combining proteomic and genomic approaches we reveal a role for DDX5 as a regulatory protein of Fra-1 signaling and suggest DDX5 as a potential therapeutic target for TNBC.
Project description:The small heat shock protein Hsp27 has been long demonstrated as a major driver of Castration Resistant Prostate Cancer (CRPC) progression via an androgen receptor-independent pathway. In the light of identification of its molecular mechanisms, we found that the RNA helicase protein DDX5 was an interactor of Hsp27 and DDX5 expression was regulated by Hsp27 through its cytoprotective function. We showed that DDX5 was overexpressed in a large collection of human samples in aggressive PCs, especially CRPC. Here, we described the protein-protein interaction network of DDX5 which were identified in four human prostate cell lines (PNT1A, LNCaP, DU-145 and PC-3) representing different disease stages using immunoaffinity purification and quantitative mass spectrometry. The DDX5 interactome in CRPC cells was enriched in several functions (DNA damage response, translation, transcription, RNA stability, and DNA conformation changes) involved in disease progression. Furthermore, we found a new critical function of DDX5 in DNA damage repair in CRPC and validated the interaction of DDX5 with the DNA repair complex Ku70/Ku86 which plays a pivotal role in the NHEJ process. We also showed that DDX5 overexpression conferred resistance to DNA damage poisoners (such as irradiation and cisplatin) in CRPC, a feature that could lead to genome maintenance, tumor progression and treatment resistance.
Project description:Fra-1, a member of the activator protein 1 (AP-1) family, is overexpressed in triple-negative breast cancer (TNBC) and plays crucial roles in tumor progression. However, a systematic analysis of the composition of the Fra-1 protein network specifically on chromatin is still missing. Here we performed endogenous purification of Fra-1 transcriptional complex under ChIP conditions, followed by mass spectrometry, to identify chromatin-bound partners of Fra-1 in TNBC cells. This study allowed the identification of 118 interactors, highlighting DDX5 as the high ranking of Fra-1 interacting proteins. DDX5, a previously unrecognized protein in the network, is recruited globally to Fra-1 binding sites and shares a substantial set of Fra-1 target genes required for the TNBC cell growth. We provide evidence that DDX5 expression enhances Fra-1 transcriptional activity, thereby enhancing Fra-1-driven tumorigenesis. By integrating ChIP-seq and RNA-seq, we show that DDX5 target gene signature predicts poor clinical outcome in breast cancer patients. DDX5 protein level was higher in triple-negative basal like tumors than in non-basal like tumors, including luminal A, luminal B and HER2-enriched subtypes. Collectively, this comprehensive Fra-1 interaction profiling provides a broad and deep view of Fra-1 chromatin interaction landscape, which will help in deciphering mechanisms of AP-1 regulation of gene expression.
Project description:RNA helicases DDX5 and DDX17 are members of a large family of highly conserved proteins involved in gene expression regulation, although their in vivo targets and activities in biological processes like cell differentiation, that requires reprogramming of gene expression programs at multiple levels, are not well characterized. In this report, we uncovered a new mechanism by which DDX5 and DDX17 cooperate with hnRNP H/F splicing factors to define epithelial- and myoblast-specific splicing subprograms. We next observed that downregulation of DDX5 and DDX17 protein expression during epithelial to mesenchymal transdifferentiation and during myogenesis contributes to switching splicing programs during these processes. Remarkably, this downregulation is mediated by the production of microRNAs induced upon differentiation in a DDX5/DDX17-dependent manner. Since DDX5 and DDX17 also function as coregulators of master transcriptional regulators of differentiation, we propose to name these proteins M-bM-^@M-^\master orchestratorsM-bM-^@M-^] of differentiation, that dynamically orchestrate several layers of gene expression. 6 samples of MCF7 cells exposed to different treatments were analyzed: 3 x siCTRLM-BM- ; 3 x si(DDX5-17) AND 6 samples of MCF10 cells exposed to different treatments were analyzed: 3 x siCTRLM-BM- ; 3 x si(DDX5-17)
Project description:We used single cell RNA sequencing (scRNA-seq) to analyze the diversity of cells within murine colonic tumors with genetic mutations.
Project description:RAR-related orphan receptor gamma (ROR t)-expressing regulatory T (ROR t+ Treg) cells play pivotal roles in preventing T cell hyperactivation and maintaining tissue homeostasis, in part, by secreting the anti-inflammation cytokine interleukin 10 (IL-10). Here, we report that Hypoxia Induced Factor 1a (HIF1alpha) is the master transcription factor for *Il10* in ROR t+ Tregs. Interestingly, this critical anti-inflammatory pathway is negatively regulated by an RNA-binding protein DEAD box helicase 5 (DDX5). As a transcriptional corepressor, DDX5 restricts the expression of HIF1 and its downstream target gene *Il10* in ROR t+ Tregs. T cell specific *Ddx5* knockout (DDX5 T) mice have augmented ROR t+ Treg suppressor activities and are better protected from intestinal inflammation. Genetic ablation or pharmacologic inhibition of HIF1a restores enteropathy susceptibility in DDX5 T mice. The DDX5-HIF1 -IL-10 pathway is conserved in mice and humans. These findings reveal potential therapeutic targets for intestinal inflammatory diseases.
Project description:To compare how WT and DDX5-/- keratinocyte in response toIL-36γ, we performed gene expression profiling analysis using data obtained from RNA-seq of WT and DDX5-/- keratinocyte stimulated by IL-36γ
Project description:Sustained spermatogenesis in adult males and recovery of fertility following germ cell depletion are dependent on undifferentiated spermatogonia with self-renewal potential. Self-renewal of undifferentiated spermatogonia is dependent on a complex network of transcriptional and post-transcriptional regulatory factors. DDX5 is known to act as a transcriptional co-regulator in other systems through interactions with key transcription factors. Here, we performed ChIP-Seq to identify target genes of DDX5 in cultured undifferentiated spermatogonia in order to elucidate its role in maintenance of the male germline.
Project description:Rhabdomyosarcoma (RMS) is the most common soft-tissue sarcoma of childhood characterized by the inability to exit the proliferative myoblast-like stage. Here, we identified the DEAD box RNA helicase 5 (DDX5) as a potential therapeutic target to inhibit alveolar rhabdomyosarcoma (ARMS) growth. We show that DDX5 is overexpressed in alveolar RMS cells, demonstrating that its depletion drastically decreases ARMS viability and slows tumor growth in xenograft models. Mechanistically, we provide evidence that DDX5 functions upstream the G9a/AKT survival signalling pathway, by modulating G9a protein stability