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The alternative PCNA loader containing CTF18-DCC1-CTF8 facilitates sister chromatid cohesion (SCC) by poorly defined mechanisms. Here we found that in DT40 cells, CTF18 acts complementarily with the Warsaw breakage syndrome DDX11 helicase in mediating SCC and proliferation. We uncover that the lethality and cohesion defects of ctf18 ddx11 mutants are associated with reduced levels of chromatin-bound cohesin and rescued by depletion of WAPL, a cohesin-removal factor. On the contrary, high levels of ESCO1/2 acetyltransferases that acetylate cohesin to establish SCC do not rescue ctf18 ddx11 phenotypes. Notably, the tight proximity of sister centromeres and increased anaphase bridges characteristic of WAPL-depleted cells are abrogated by loss of both CTF18 and DDX11. The results reveal that vertebrate CTF18 and DDX11 collaborate to provide sufficient amounts of chromatin-loaded cohesin available for SCC generation in the presence of WAPL-mediated cohesin-unloading activity. This process modulates chromosome structure and is essential for cellular proliferation in vertebrates.

A trisomy is a type of aneuploidy characterised by an additional chromosome. The additional chromosome theoretically accepts any kind of changes since it is not necessary for cellular proliferation. This advantage led us to apply two chromosome manipulation methods to autosomal trisomy in chicken DT40 cells. We first corrected chromosome 2 trisomy to disomy by employing counter-selection markers. Upon construction of cells carrying markers targeted in one of the trisomic chromosome 2s, cells that have lost markers integrated in chromosome 2 were subsequently selected. The loss of one of the chromosome 2s had little impacts on the proliferative capacity, indicating unsubstantial role of the additional chromosome 2 in DT40 cells. We next tested large-scale truncations of chromosome 2 to make a mini-chromosome for the assessment of chromosome stability by introducing telomere repeat sequences to delete most of p-arm or q-arm of chromosome 2. The obtained cell lines had 0.7 Mb mini-chromosome, and approximately 0.2% of mini-chromosome was lost per cell division in wild-type background while the rate of chromosome loss was significantly increased by the depletion of DDX11, a cohesin regulatory protein. Collectively, our findings propose that trisomic chromosomes are good targets to make unique artificial chromosomes.

Esophageal carcinoma (ESCA) is one of the most aggressive malignancies with extremely high morbidity and mortality. At present, limited advancement in ESCA treatment has achieved. Therefore, it is urgent to explore the pathogenesis and progression mechanism of ESCA to provide the basis for the formulation of novel therapeutic strategies. Previous studies have found that long non-coding RNA (lncRNA) DDX11-AS1 expression enhances the paclitaxel resistance of ESCA cells. However, the mechanisms underlying the drug resistance conferred by lncRNA DDX11-AS1 in ESCA remains to be elucidated. Our research aims to clarify the role and mechanism of lncRNA DDX11-AS1 in regulating the progression of ESCA. We found that the expression of lncRNA DDX11-AS1 in ESCA tissues and cell lines was significantly upregulated. Subsequently, silencing lncRNA DDX11-AS1 significantly inhibited the proliferation, migration and invasion of ESCA cells, and induced the level of cell apoptosis. In terms of mechanism, our data showed that miR-514b-3p/RING box protein 1 (RBX1) axis played a crucial role in the oncogenic function of lncRNA DDX11-AS1. LncRNA DDX11-AS1 expression impaired the inhibitory function of miR-514b-3p on RBX1 through sponging effect. Taken together, our data support the notion that lncRNA DDX11-AS1 promotes the progression of ESCA through miR-514b-3p/RBX1 axis. Our research uncovers the novel regulatory role of lncRNA DDX11-AS1 in ESCA and lays a theoretical basis for developing novel treatment strategy of ESCA., Graphical abstract

Background: As a subtype of human genitourinary system cancer, the morbidity of bladder cancer (BC) continues to rise. Because of the high potentiality of cell metastasis, the 5-year survival rate ...

The DEAD/DEAH box helicase 11 (DDX11) plays vital roles in regulating the initiation of DNA replication. However, its precise function and regulation in hepatocellular carcinoma (HCC) have never been reported yet. In the current study, we found that DDX11 was overexpressed in HCC tissues. High DDX11 expression was positively correlated with large tumor size, tumor multiplicity, late tumor-node-metastasis (TNM) stage and poor prognosis. Additional, gain-of-function and loss-of-function experimental results revealed that DDX11 overexpression promoted HCC cell proliferation, migration, invasion and inhibited cell apoptosis in vitro. Overexpression of DDX11 also enhanced HCC tumorigenicity in vivo. Furthermore, DDX11 was transcriptionally regulated by transcription factor E2F1 in HCC, as demonstrated by chromatin immunoprecipitation (Ch-IP) and luciferase reporter assays. Mechanistically, E2F1/DDX11 axis promoted HCC cell proliferation, migration and invasion, at least in part, through activating PI3K/AKT/mTOR signaling pathway. Conclusively, our study demonstrates that E2F1-enhanced DDX11 expression promotes HCC progression through PI3K/AKT/mTOR pathway and DDX11 might be a potential therapeutic and prognostic target for HCC treatment.

Gastric cancer (GC) is a malignant tumour with high lethality. Accruing evidence elucidates the critical adjusting role of long non-coding RNA (lncRNAs) in human cancers. DDX11 antisense RNA 1 (DDX11-AS1) was previously found to be involved in GC pathogenesis. However, the precise molecular mechanisms of DDX11-AS1 need to be further investigated. In this study, we found that DDX11-AS1 expression was up-regulated in GC tumour tissues and cells. Increased DDX11-AS1 expression was associated with advanced TNM stage and lymph node metastasis. Functionally, knockdown of DDX11-AS1 repressed cell proliferation and clone formation, while induced cell cycle arrest and apoptosis. As expected, DDX11-AS1 overexpression displayed the opposite effect. Mechanically, DDX11-AS1 enhanced SPC18 expression through acting as a ceRNA for miR-873-5p. Furthermore, the inhibitory effect of DDX11-AS1 silencing on malignant biological behaviour of GC cells was attenuated by either miR-873-5p inhibitor or SEC11A up-regulation. Moreover, suppression of DDX11-AS1 also decreased GC tumorigenesis in vivo. In conclusion, DDX11-AS1 may serve as an oncogene in GC progression by sponging miR-873-5p and promoting SPC18 expression, providing a new insight into the mechanisms of DDX11-AS1 and elucidating a promising therapy target in GC.

Warsaw breakage syndrome (WABS) is a very rare recessive hereditary disease caused by mutations in the gene coding for the DNA helicase DDX11, involved in genome stability maintenance and sister cohesion establishment. Typical clinical features observed in WABS patients include growth retardation, facial dysmorphia, microcephaly, hearing loss due to cochlear malformations and, at cytological level, sister chromatid cohesion defects. Molecular bases of WABS have not yet been elucidated, due to lack of disease animal model systems and limited knowledge of the DDX11 physiological functions. However, WABS is considered to belong to the group of cohesinopathies, genetic disorders due to mutations of subunits or regulators of cohesin, the protein complex responsible for tethering sister chromatids from the time of their synthesis till they separate in mitosis. Recent evidences suggest that cohesin and its regulators have additional key roles in chromatin organization by promoting the formation of chromatin loops. This "non-canonical" function of cohesin is expected to impact gene transcription during cell differentiation and embryonic development and its dis-regulation, caused by mutation/loss of genes encoding cohesin subunits or regulators, could originate the developmental defects observed in cohesinopathies. Ethiopathogenesis of WABS is discussed in line with these recent findings and evidence of a possible role of DDX11 as a cohesin regulator.

Warsaw breakage syndrome (WABS), caused by bi-allelic variants in the DDX11 gene, is a rare cohesinopathy characterized by pre- and postnatal growth retardation, microcephaly, intellectual disability, facial dysmorphia, and sensorineural hearing loss due to cochlear hypoplasia. The DDX11 gene codes for an iron-sulfur DNA helicase in the Superfamily 2 helicases and plays an important role in genomic stability and maintenance. Fourteen individuals with WABS have been previously reported in the medical literature. Affected individuals have been of various ethnic backgrounds with different pathogenic variants. We report two unrelated individuals of Ashkenazi Jewish descent affected with WABS, who are homozygous for the c.1763-1G>C variant in the DDX11 gene. Their phenotype is consistent with previously reported individuals. RNA studies showed that this variant causes an alternative splice acceptor site leading to a frameshift in the open reading frame. Carrier screening of the c.1763-1G>C variant in the Jewish population revealed a high carrier frequency of 1 in 68 in the Ashkenazi Jewish population. Due to the high carrier frequency and the low number of affected individuals, we hypothesize a high rate of miscarriage of homozygous fetuses and/or subfertility for carrier couples. If the carrier frequency is reproducible in additional Ashkenazi Jewish populations, we suggest including DDX11 to Ashkenazi Jewish carrier screening panels.

Background: Lung adenocarcinoma (ADC) is the main cause of cancer-related mortality in lung cancer patients. DEAD/DEAH box helicase 11 (DDX11) was previously shown to be dysregulated and to exert oncogenic activity in cancer. However, the diagnostic value and clinical significance of DDX11 in ADC remain unknown. Methods: A total of 513 ADC and 59 normal tissue samples were obtained from The Cancer Genome Atlas (TCGA) database, and the mRNA expression level of DDX11 in ADC was evaluated. Additionally, a meta-analysis of 7 ADC cohorts from the Gene Expression Omnibus (GEO) database was conducted to validate the DDX11 expression pattern. Moreover, receiver operating characteristic (ROC) curve analysis was used to identify the diagnostic power of DDX11 in ADC. A tissue microarray (TMA) comprising 86 ADC specimens and their adjacent normal specimens was applied to indicate DDX11 protein expression status. In addition, Kaplan-Meier and Cox regression analyses were conducted to validate the prognostic value of DDX11 in ADC. Finally, the molecular mechanism of DDX11 action in ADC was predicted by gene set enrichment analysis (GSEA). Results: DDX11 was upregulated in ADC tissues and was associated with worse overall survival (OS). ROC curves of DDX11 showed high values for diagnosis. Additionally, DDX11 expression has remarkable correlations with DNA replication and the cell cycle G1-S phase pathway. Consistently, it was associated with cell cycle genes, such as CCNA2, CCNB1, CCNC, CCND1, CCNE1, CDK2, CDK4 and CDK6. Moreover, high CCNA2, CCNB1, CCNE1 and CDK6 expression in ADC patients predicted worse OS and progression-free survival (PFS). Conclusion: DDX11 was significantly upregulated and predicted poor prognosis in ADC. This gene might serve as a potential novel prognostic and diagnostic biomarker for ADC.

DDX11/ChlR1 is a super-family two iron–sulfur cluster containing DNA helicase with roles in DNA replication and sister chromatid cohesion establishment, and general chromosome architecture. Bi-allelic mutations of the DDX11 gene cause a rare hereditary disease, named Warsaw breakage syndrome, characterized by a complex spectrum of clinical manifestations (pre- and post-natal growth defects, microcephaly, intellectual disability, heart anomalies and sister chromatid cohesion loss at cellular level) in accordance with the multifaceted, not yet fully understood, physiological functions of this DNA helicase. In the last few years, a possible role of DDX11 in the onset and progression of many cancers is emerging. Herein we summarize the results of recent studies, carried out either in tumoral cell lines or in xenograft cancer mouse models, suggesting that DDX11 may have an oncogenic role. The potential of DDX11 DNA helicase as a pharmacological target for novel anti-cancer therapeutic interventions, as inferred from these latest developments, is also discussed.

Hepatocellular carcinoma (HCC) accounts for one of the leading causes of cancer-related death, and is attributed to the dysregulation of genes involved in genome stability. DDX11, a DNA helicase, has been implicated in rare genetic disease and human cancers. Yet, its clinical value, biological function, and the underlying mechanism in HCC progression are not fully understood. Here, we show that DDX11 is upregulated in HCC and exhibits oncogenic activity via EZH2/p21 signaling. High expression of DDX11 is significantly correlated with poor outcomes of HCC patients in two independent cohorts. DDX11 overexpression increases HCC cell viabilities and colony formation, whereas DDX11 knockdown arrests cells at G1 phase without alteration of p53 expression. Ectopic expression of DDX11 reduces, while depletion of DDX11 induces the expression of p21. Treatment of p21 siRNA markedly attenuates the cell growth suppression caused by DDX11 silence. Further studies reveal that DDX11 interacts with EZH2 in HCC cells to protect it from ubiquitination-mediated protein degradation, consequently resulting in the downregulation of p21. In addition, E2F1 is identified as one of the upstream regulators of DDX11, and forms a positive feedback loop with EZH2 to upregulate DDX11 and facilitate cell proliferation. Collectively, our data suggest DDX11 as a promising prognostic factor and an oncogene in HCC via a E2F1/DDX11/EZH2 positive feedback loop.

Warsaw breakage syndrome (WABS) is a genetic disorder characterized by sister chromatid cohesion defects, growth retardation, microcephaly, hearing loss and other variable clinical manifestations. WABS is due to biallelic mutations of the gene coding for the super-family 2 DNA helicase DDX11/ChlR1, orthologous to the yeast chromosome loss protein 1 (Chl1). WABS is classified in the group of “cohesinopathies”, rare hereditary diseases that are caused by mutations in genes coding for subunits of the cohesin complex or protein factors having regulatory roles in the sister chromatid cohesion process. In fact, among the cohesion regulators, an important player is DDX11, which is believed to be important for the functional coupling of DNA synthesis and cohesion establishment at the replication forks. Here, we will review what is known about the molecular and cellular functions of human DDX11 and its role in WABS etiopathogenesis, even in light of recent findings on the role of cohesin and its regulator network in promoting chromatin loop formation and regulating chromatin spatial organization.

Objectives: This study employed genetic and functional analyses using OASIS meta-analysis of multiple existing GWAS and gene-expression datasets to identify novel SLE genes. Methods: Four hundred and ten genes were mapped using SNIPPER to 30 SLE GWAS loci and investigated for expression in three SLE GEO-datasets and the Cordoba GSE50395-dataset. Blood eQTL for significant SNPs in SLE loci and STRING for functional pathways of differentially expressed genes were used. Confirmatory qPCR on SLE monocytes was performed. The entire 12p11 locus was investigated for genetic association using two additional GWAS. Expression of 150 genes at this locus was assessed. Based on this significance, qPCRs for DNM1L and KRAS were performed. Results: Fifty genes were differentially expressed in at least two SLE GEO-datasets, with all probes directionally aligned. DDX11, an RNA helicase involved in genome stability, was downregulated in both GEO and Cordoba datasets. The most significant SNP, rs3741869 in OASIS locus 12p11.21, containing DDX11, was a cis-eQTL regulating DDX11 expression. DDX11 was found repressed. The entire 12p11 locus showed three association peaks. Gene expression in GEO datasets identified DNM1L and KRAS, besides DDX11. Confirmatory qPCR validated DNM1L as an SLE susceptibility gene. DDX11, DNM1L and KRAS interact with each other and multiple known SLE genes including STAT1/STAT4 and major components of IFN-dependent gene expression, and are responsible for signal transduction of cytokines, hormones, and growth-factors, deregulation of which is involved in SLE-development. Conclusion: A genomic convergence approach with OASIS analysis of multiple GWAS and expression datasets identified DDX11 and DNM1L as novel SLE-genes, the expression of which is altered in monocytes from SLE patients. This study lays the foundation for understanding the pathogenic involvement of DDX11 and DNM1L in SLE by identifying them using a systems-biology approach, while the 12p11 locus harboring these genes was previously missed by four independent GWAS.

Graphical abstract, DEAD/H box helicases are implicated in lung cancer but have not been systematically investigated for their clinical significance and function. In this study, we aimed to evaluate the potential of DEAD/H box helicases as prognostic biomarkers and therapeutic targets in lung cancer by integrated bioinformatic analysis of multivariate large-scale databases. Survival and differential expression analysis of these helicases enabled us to identify four biomarkers with the most significant alterations. These were found to be the negative prognostic factors DDX11, DDX55 and DDX56, and positive prognostic factor DDX5. Pathway enrichment analysis indicates that MYC signalling is negatively associated with expression levels of the DDX5 gene while positively associated with that of DDX11, DDX55 and DDX56. High expression levels of the DDX5 gene is associated with low mutation levels of TP53 and MUC16, the two most frequently mutated genes in lung cancer. In contrast, high expression levels of DDX11, DDX55 and DDX56 genes are associated with high levels of TP53 and MUC16 mutation. The tumour-infiltrated CD8 + T and B cells positively correlate with levels of DDX5 gene expression, while negatively correlate with that of the other three DEAD box helicases, respectively. Moreover, the DDX5-associated miRNA profile is distinguished from the miRNA profiles of DDX11, DDX55 and DDX56, although each DDX has a different miRNA signature. The identification of these four DDX helicases as biomarkers will be valuable for prognostic prediction and targeted therapeutic development in lung cancer.

Warsaw breakage syndrome (WABS), is caused by biallelic mutations of DDX11, a gene coding a DNA helicase. We have recently reported two affected sisters, compound heterozygous for a missense (p.Leu836Pro) and a frameshift (p.Lys303Glufs*22) variant. By investigating the pathogenic mechanism, we demonstrate the inability of the DDX11 p.Leu836Pro mutant to unwind forked DNA substrates, while retaining DNA binding activity. We observed the accumulation of patient-derived cells at the G2/M phase and increased chromosomal fragmentation after mitomycin C treatment. The phenotype partially overlaps with features of the Fanconi anemia cells, which shows not only genomic instability but also defective mitochondria. This prompted us to examine mitochondrial functionality in WABS cells and revealed an altered aerobic metabolism. This opens the door to the further elucidation of the molecular and cellular basis of an impaired mitochondrial phenotype and sheds light on this fundamental process in cell physiology and the pathogenesis of these diseases.

How the replisome senses and deals with DNA secondary structures has been a mystery. A new study from the Sale and Pellegrini laboratories finds that the Timeless protein has a G-quadruplex binding domain that works together with the DDX11 helicase to facilitate replication of G4 DNA structures.

Genome-wide association studies (GWAS) of systemic lupus erythematosus (SLE) explain only ∼15% of genetic risk, indicating genes of modest effect remain to be discovered. Association clustering methods such as OASIS are more apt at identifying modest genetic effects. 410 genes were mapped to previously identified OASIS GWAS SLE loci and investigated for expression in SLE GEO datasets. GSE50395 dataset from Cordoba was used for validation. Blood eQTL for significant SNPs in SLE loci and STRING for functional pathways of differentially expressed genes was used. Confirmatory qPCR on monocytes of 12 SLE patients and controls was performed. We identified 55 genes that were differentially expressed in at least 2 SLE GEO datasets with all probes directionally aligned. DDX11 was downregulated in both GEO (P=3.60E-02) and Cordoba (P=8.02E-03) datasets and confirmed by qPCR (P=0.001). The most significant SNP, rs3741869 (P=3.2E-05) in OASIS locus 12p11.21, containing DDX11, was a cis-eQTL regulating DDX11 expression (P=8.62E-05). DDX11 interacted with multiple genes including STAT1/STAT4. Genomic convergence with OASIS and multiple expression datasets identifies novel genes. DDX11, RNA helicase involved in genome stability, is repressed in SLE.Summary StatementMore than 100 genes for SLE have been identified but they explain only ∼15% of heritability. GWAS are challenged by risk genes of modest effect. Using locus-based GWAS mapping and multiple gene expression replications, DDX11 was identified as a novel SLE gene. DDX11, repressed in SLE, may be used as a clinical diagnostic tool.

Warsaw Breakage Syndrome (WABS) is a rare disorder related to cohesinopathies and Fanconi anemia, caused by bi-allelic mutations in DDX11. Here, we report multiple compound heterozygous WABS cases, each displaying destabilized DDX11 protein and residual DDX11 function at the cellular level. Patient-derived cell lines exhibit sensitivity to topoisomerase and PARP inhibitors, defective sister chromatid cohesion and reduced DNA replication fork speed. Deleting DDX11 in RPE1-TERT cells inhibits proliferation and survival in a TP53-dependent manner and causes chromosome breaks and cohesion defects, independent of the expressed pseudogene DDX12p. Importantly, G-quadruplex (G4) stabilizing compounds induce chromosome breaks and cohesion defects which are strongly aggravated by inactivation of DDX11 but not FANCJ. The DNA helicase domain of DDX11 is essential for sister chromatid cohesion and resistance to G4 stabilizers. We propose that DDX11 is a DNA helicase protecting against G4 induced double-stranded breaks and concomitant loss of cohesion, possibly at DNA replication forks., WABS patient derived cells display loss of sister chromatid cohesion. Here the authors by analyzing WABS patient derived cells, reveal a role of the DDX11 helicase in resolving G-Quadruplex structures to support sister chromatid cohesion.

BACKGROUND Myelodysplastic syndromes (MDS) represent a heterogeneous group of myeloid malignancies characterized by cytopenia and increased risk of progression to acute myeloid leukemia (AML) driven by accumulated somatic mutations in hematopoietic stem cells (HSCs). While recurrent mutations are known to associate with adverse outcomes in myelodysplastic syndrome (MDS), 10% of MDS cases have no known genetic indicators for survival prognosis. Whole genome sequencing (WGS) detects comprehensive mutations on coding and non-coding regions that empowers discovery of novel genetic biomarkers. METHODS We conducted WGS at 60x read depth on 494 MDS patient subjects and scanned genome-wide for novel somatic biomarkers associated with MDS post allogeneic hematopoietic cell transplantation (allo-HCT) outcomes. Forward and backward stepwise variable selection was performed, and important clinical covariables were integrated into multivariate Cox proportional hazard models for survival outcome association tests. To test for associations with overall survival (OS), we conducted burden tests of somatic variants by summing the number of somatic nonsynonymous (missense, nonsense, splice) mutations per gene and testing for association with OS. For non-coding regions, we applied a sliding window approach, summing somatic mutations within each 10kb window and testing for association with OS. Furthermore, to distinguish potentially novel biomarkers from mutations in known MDS prognostic genes, we re-ran our association analyses considering only those MDS subjects with no known mutations in previously-identified prognostic genes for post allo-HCT survival(including TP53, RAS, JAK2, TET2, EZH2, ETV6, RUNX1, DNMT3A and ASXL1). RESULTS Genome-wide analyses of somatic coding variants on OS identified two statistically significant associations (Figure 1A I); one at TP53 (hazard ratio [HR], 2.19; 95% confidence intervals [CI] 1.48-2.75; P = 1.51e-06) and the other at HCN2 (HR, 5.84; 95% CI 2.38-14.34; P=1.18E-04). When we restricted our analyses to those patients with no mutations in known prognostic genes (N=301), we found one statistically significant candidate at DDX11 (HR, 3.74; 95% CI 1.87-7.47; P=1.83E-04). When we expanded our analyses to include non-coding somatic variants, we observed five additional significant genes (Figure 1A II, IV) including CHD1 (HR, 7.31; 95% CI 3.33-16.08; P=7.45E-07) that was significantly associated with post allo-HCT OS in the patient subset with no known mutations. Meta-analyses of OS using TCGA lymphoma and AML/MDS data provided validation that DDX11 and CHD1 mutations are associated with poor overall survival in hematopoietic malignancies (data not shown). Interestingly, many of the candidates from these analyses (e.g., DDX11, CHD1, RASGRF1 and ARHGEF7) are involved in DNA repair pathways. Gene set enrichment analyses confirmed that our association results are enriched a TP53-centered networks (p value: 0.0042, Figure 1B). Besides the novel candidates, a known MDS prognostic gene TP53 was replicated by our nonbiased screening approach. Co-occurrence of TP53 mutation and complex karyotypes, as well as high VAF of TP53 mutations in our MDS cohort were highly associated with poor post allo-HCT OS (data not shown). MDS patients with TP53, DDX11 and CHD1 mutations were overrepresented in samples with complex karyotypes. CONCLUSIONS Overall, through WGS of samples obtained at the time of allo-HCT, we identified two novel genetic prognostic biomarkers, DDX11 and CHD1 mutations, which were associated with inferior post allo-HCT OS. These results once validated could contribute to personalized risk assessments of post HCT outcomes for MDS patients. Figure 1 Figure 1. Disclosures Saber: Govt. COI: Other.

Increasing evidence has uncovered that long noncoding RNAs (lncRNAs) play extremely important roles in numerous steps of gene regulation concerning the progression of tumors. Defined as a kind of lncRNA, DDX11-AS1 has been considered to be closely related to the tumorigenesis of malignancies. Nevertheless, the underlying regulatory role of it in osteosarcoma remains to be analyzed and elucidated. In this research, a dramatically upregulated expression of DDX11-AS1 was detected in osteosarcoma cells. Loss-of-function assays revealed that decreased expression of DDX11-AS1 impaired osteosarcoma cell proliferation, metastasis as well as epithelial-mesenchymal transition (EMT) process. Afterwards, molecular mechanism tests validated that DDX11-AS1 could sponge miR-873-5p to upregulate DDX11 expression in osteosarcoma. Additionally, functional tests delineated that upregulation of miR-873-5p inhibited cell proliferation, metastasis as well as EMT process in osteosarcoma progression. Further, DDX11-AS1 was verified to regulate the mRNA stability of DDX11 through binding with IGF2BP2 in osteosarcoma. Final rescue tests in vitro and in vivo further elucidated that DDX11 overexpression could reversed the DDX11-AS1 downregulation-mediated effect on osteosarcoma progression. To sum up, DDX11-AS1 contributes to osteosarcoma progression via stabilizing DDX11.

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, and fatal interstitial lung disease. Therapeutic options for IPF remain limited. Nintedanib, a tyrosine kinase inhibitor approved for IPF treatment, is known to inhibit fibroblasts proliferation, migration and transformation to myofibroblasts. However, how nintedanib changes gene regulations in IPF has never been systematically investigated. We conducted a next-generation sequencing and bioinformatics study to evaluate the changes of mRNA and miRNA profiles in IPF fibroblasts treated with 2 &micro, M and 4 &micro, M nintedanib, compared to those without treatment. We identified 157 upregulated and 151 downregulated genes and used STRING and DAVID databases for analysis of protein&ndash, protein interactions, biological pathways, and molecular functions. We found strong protein&ndash, protein interactions within these dysregulated genes, mostly involved in the pathways of cell cycle and mitotic cell cycle. We also discovered 13 potential miRNA&ndash, mRNA interactions associated with nintedanib treatment. After validation using miRDB, TargetScan, and RT-qPCR, we identified 4 downregulated genes (DDX11, E2F1, NPTX1, and PLXNA4) which might be repressed by the upregulated hsa-miR-486-3p. According to the proposed functions of DDX11, E2F1, and PLXNA4 reported in previous studies, these gene expression changes together might contribute to decreased proliferation of fibroblasts and decreased angiogenesis in the microenvironment of IPF. Our findings need further studies to confirm.

Double-stranded DNA and RNA, and DNA/RNA hybrids form naturally in cells between two nucleic acid strands containing complementary sequences. However, these double-stranded nucleic acid structures need to be separated for DNA replication, RNA transcription, RNA processing, and DNA repair. These cellular processes are vital for normal cell growth and efficient recovery from environmental insults that damage DNA. Normally during these processes, DNA and RNA helicases unwind the double-stranded nucleic acid structures. Thus dysfunctions in these helicases contribute to a variety of clinical symptoms, including developmental abnormalities, mental retardation, neuromuscular degeneration, premature aging, and cancer predisposition. This review surveys the human diseases that have been linked to mutations in the helicase genes ATRX, BLM, CSA/B, DDX11, FANCJ/M, IFIH1, IGHMBP2, MCM4/5, RECQ4, RTEL1, SETX, TWINKLE, WRN, and XPB/D. The molecular functions of these helicases are also discussed.

Background: Warsaw Breakage Syndrome (WABS) is an ultra rare cohesinopathy caused by biallelic mutation of DDX11 gene. It is clinically characterized by pre and postnatal growth delay, microcephaly, hearing loss with cochlear hypoplasia, skin color abnormalities, and dysmorphisms. Methods: Mutational screening and functional analyses (protein expression and 3D-modeling) were performed in order to investigate the presence and pathogenicity of DDX11 variant identified in our patients. Results: We report the clinical history of two sisters affected by WABS with a pathological mytomicin C test carrying compound heterozygous mutations (c.2507T>C / c.907_920del) of the DDX11 gene. The pathogenicity of this variant was confirmed in the light of a bioinformatic study and protein three-dimensional modeling, as well as expression analysis. Conclusion: These findings further extend the clinical and molecular knowledge about the WABS showing a possible mild phenotype without major malformations or intellectual disability.

Warsaw breakage syndrome (WABS) is a very rare recessive hereditary disease caused by mutations in the gene coding for the DNA helicase DDX11, involved in genome stability maintenance and sister cohesion establishment. Typical clinical features observed in WABS patients include growth retardation, facial dysmorphia, microcephaly, hearing loss due to cochlear malformations and, at cytological level, sister chromatid cohesion defects. Molecular bases of WABS have not yet been elucidated, due to lack of disease animal model systems and limited knowledge of the DDX11 physiological functions. However, WABS is considered to belong to the group of cohesinopathies, genetic disorders due to mutations of subunits or regulators of cohesin, the protein complex responsible for tethering sister chromatids from the time of their synthesis till they separate in mitosis. Recent evidences suggest that cohesin and its regulators have additional key roles in chromatin organization by promoting the formation of chromatin loops. This "non-canonical" function of cohesin is expected to impact gene transcription during cell differentiation and embryonic development and its dis-regulation, caused by mutation/loss of genes encoding cohesin subunits or regulators, could originate the developmental defects observed in cohesinopathies. Ethiopathogenesis of WABS is discussed in line with these recent findings and evidence of a possible role of DDX11 as a cohesin regulator.

Simple Summary DDX11, a helicase involved in sister chromatid cohesion, was identified as a significant biomarker of aggressive renal cell carcinoma (RCC) in our previous studies. In this study, we evaluated the molecular pathways through which DDX11 is involved in RCC cell survival. Furthermore, we assessed the sensitivity of poly (ADP-ribose) polymerase (PARP) inhibitors, which have not been used in RCC treatment, in association with DDX11 expression. DDX11-deficient RCC inhibited RCC proliferation, caused defects in segregation, and increased apoptosis. DDX11-deficient RCC was associated with increased sensitivity to PARP inhibition. DDX11 could be a novel therapeutic and prognostic biomarker for RCC patients, and this study is the first to suggest the use of PARP inhibitors in DDX11-deficient RCC patients. Abstract Genes associated with the DEAD-box helicase DDX11 are significant biomarkers of aggressive renal cell carcinoma (RCC), but their molecular function is poorly understood. We analyzed the molecular pathways through which DDX11 is involved in RCC cell survival and poly (ADP-ribose) polymerase (PARP) inhibitor sensitivity. Immunohistochemistry and immunoblotting determined DDX11 expression in normal kidney tissues, benign renal tumors, and RCC tissues and cell lines. Quantitative polymerase chain reaction validated the downregulation of DDX11 in response to transfection with DDX11-specific small interfering RNA. Proliferation analysis and apoptosis assays were performed to determine the impact of DDX11 knockdown on RCC cells, and the relevant effects of sunitinib, olaparib, and sunitinib plus olaparib were evaluated. DDX11 was upregulated in high-grade, advanced RCC compared to low-grade, localized RCC, and DDX11 was not expressed in normal kidney tissues or benign renal tumors. DDX11 knockdown resulted in the inhibition of RCC cell proliferation, segregation defects, and rapid apoptosis. DDX11-deficient RCC cells exhibited significantly increased sensitivity to olaparib compared to sunitinib alone or sunitinib plus olaparib combination treatments. Moreover, DDX11 could determine PARP inhibitor sensitivity in RCC. DDX11 could serve as a novel therapeutic biomarker for RCC patients who are refractory to conventional targeted therapies and immunotherapies.

Long noncoding RNAs (lncRNAs) are involved in diverse cellular processes through multiple mechanisms. Here, we describe a previously uncharacterized human lncRNA, CONCR (cohesion regulator noncoding RNA), that is transcriptionally activated by MYC and is upregulated in multiple cancer types. The expression of CONCR is cell cycle regulated, and it is required for cell-cycle progression and DNA replication. Moreover, cells depleted of CONCR show severe defects in sister chromatid cohesion, suggesting an essential role for CONCR in cohesion establishment during cell division. CONCR interacts with and regulates the activity of DDX11, a DNA-dependent ATPase and helicase involved in DNA replication and sister chromatid cohesion. These findings unveil a direct role for an lncRNA in the establishment of sister chromatid cohesion by modulating DDX11 enzymatic activity.