scholarly journals Polycomb-mediated repression of EphrinA5 promotes growth and invasion of glioblastoma

2019 ◽  
Vol 21 (Supplement_4) ◽  
pp. iv1-iv2
Author(s):  
Thomas Oliver Millner ◽  
Barbara Ricci ◽  
Xinyu Zhang ◽  
Nicola Pomella ◽  
Silvia Marino

Abstract Introduction The epigenetic regulator Bmi1 is essential for the self-renewal of neural stem cells (NSC), and highly expressed in glioblastoma (GBM) stem/initiating cells (GIC), where knockdown significantly reduces tumour growth in xenograft models. We have used a combined genome-wide and target gene-driven approach to identify EphrinA5 (EfnA5) as a mediator of Bmi1 function in mouse and human GIC. Methods and results We compared mGIC, from a PTEN/p53 deletion mouse model, to matched NSC. Combined ChIPSeq and RNASeq showed a differential redistribution of the repressive PRC mark H3K27me3 in mGIC, and that transcriptional regulation is Bmi1-dependent in a proportion of H3K27me3 marked genes. Subsequently, using shRNA knockdown, we show that Bmi1 regulates cell morphology, proliferation and migration/invasion via repression of EfnA5 in mGIC, and that the same mechanism is essential for GBM development in an allograft model. To confirm the translational potential of the BMI1/EFNA5 pathway we examined published RNA microarray, RNAseq and single-cell RNAseq datasets and found a significant inverse relationship between BMI1 and EFNA5. Finally, we show that BMI1 also regulates cell proliferation via repression of EFNA5 in primary human GIC in vitro. Conclusions We present evidence from a mouse model, human expression datasets and human primary cells showing that the Bmi1-EfnA5 pathway plays a prominent regulatory role in GIC. As the anti-proliferative role of BMI1 silencing is mediated by de-repression of EFNA5 in hGIC, precision targeting of Ephrin signalling, for example with agents that mimic EFNA5 action, could be an effective therapeutic tool in human GBM overexpressing BMI1.

Author(s):  
Jin-Soo Park ◽  
RyeonJin Cho ◽  
Eun-Young Kang ◽  
Yeon-Mok Oh

AbstractEmphysema, a pathological component of chronic obstructive pulmonary disease, causes irreversible damage to the lung. Previous studies have shown that Slit plays essential roles in cell proliferation, angiogenesis, and organ development. In this study, we evaluated the effect of Slit2 on the proliferation and migration of mouse lung epithelial cells and its role in regeneration in an emphysema lung mouse model. Here, we have shown that Slit2/Robo signaling contributes to the regeneration of lungs damaged by emphysema. Mouse epithelial lung cells treated with Slit2 exhibited increased proliferation and migration in vitro. Our results also showed that Slit2 administration improved alveolar regeneration in the emphysema mouse model in vivo. Furthermore, Slit2/Robo signaling increased the phosphorylation of ERK and Akt, which was mediated by Ras activity. These Slit2-mediated cellular signaling processes may be involved in the proliferation and migration of mouse lung epithelial cells and are also associated with the potential mechanism of lung regeneration. Our findings suggest that Slit2 administration may be beneficial for alveolar regeneration in lungs damaged by emphysema.


2021 ◽  
Vol 11 ◽  
Author(s):  
Tinghui Duan ◽  
Diyuan Zhou ◽  
Yizhou Yao ◽  
Xinyu Shao

Colorectal cancer (CRC) is one of the most frequent malignant neoplasms worldwide, and the effect of treatments is limited. Fibroblast growth factor 1 (FGF1) has been involved in a wide variety of several malignant diseases and takes part in the tumorigenesis of CRC. However, the function and mechanism of FGF1 in CRC remains elusive. In this study, the results indicated that FGF1 is elevated in CRC tissues and linked with poor prognosis (P < 0.001). In subgroup analysis of FGF1 in CRC, regardless of any clinic-factors except gender, high level FGF1 expression was associated with markedly shorter survival (P < 0.05). In addition, the expression of p-S6K1 and FGF1 was not associated in normal tissue (P = 0.781), but their expression was closely related in tumor tissue (P = 0.010). The oncogenic role of FGF1 was determined using in vitro and in vivo functional assays. FGF1 depletion inhibited the proliferation and migration of CRC cells in vitro and vivo. FGF1 was also significantly correlated with mTOR-S6K1 pathway on the gene and protein levels (P < 0.05). In conclusion, FGF1 acts as a tumor activator in CRC, and against FGF1 may provide a new visual field on treating CRC, especially for mTORC1-targeted resistant patients.


2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Yi Cao ◽  
Li Xu ◽  
Xiaohong Yang ◽  
Yuan Dong ◽  
Hongbin Luo ◽  
...  

Background. Refractory wound healing is a severe complication of diabetes with a significant socioeconomic burden. Whereas current therapies are insufficient to accelerate repair, stem cell-based therapy is increasingly recognized as an alternative that improves healing outcomes. The aim of the present study is to explore the role of cycloastragenol (CAG), a naturally occurring compound in Astragali Radix, in ameliorating refractory cutaneous wound healing in vitro, which may provide a new insight into therapeutic strategy for diabetic wounds. Methods. Human epidermal stem cells (EpSCs) obtained from nine patients were exposed to CAG, with or without DKK1 (a Wnt signaling inhibitor). A lentiviral short hairpin RNA (shRNA) system was used to establish the telomerase reverse transcriptase (TERT) and β-catenin knockdown cell line. Cell counting kit-8, scratch wound healing, and transwell migration assay were used to determine the effects of CAG in cell growth and migration. The activation of TERT, β-catenin, and c-Myc was determined using real-time qPCR and western blot analysis. Chromatin immunoprecipitation (ChIP) was performed to evaluate the associations among CAG, TERT, and Wnt/β-catenin signals. Results. CAG not only promoted the proliferation and migration ability of EpSCs but also increased the expression levels of TERT, β-catenin, c-Myc. These effects of CAG were most pronounced at a dose of 0.3 μM. Notably, the CAG-promoted proliferative and migratory abilities of EpSCs were abrogated in TERT and β-catenin-silenced cells. In addition, the ChIP results strongly suggested that CAG-modulated TERT was closely associated with the activation of Wnt/β-catenin signaling. Conclusion. Our data indicate that CAG is a TERT activator of EpSCs and is associated with their proliferation and migration, a role it may play through the activation of Wnt/β-catenin signaling.


2019 ◽  
Vol 133 (22) ◽  
pp. 2265-2282 ◽  
Author(s):  
Zhengzhe Feng ◽  
Xiaoxi Zhang ◽  
Li Li ◽  
Chuanchuan Wang ◽  
Mingtao Feng ◽  
...  

Abstract Tumor-associated macrophages (TAMs) play a regulatory role in inflammation and cancer. Exosomes derived from macrophages carrying microRNAs (miRNAs or miRs) are of great value for cancer therapy. Gremlin 1 (GREM1), a member of the antagonists of secreted bone morphogenetic protein, has been implicated in the pathophysiology of multiple diseases or cancers. Based on the predictions of miRNA–mRNA interaction, GREM1 was found to be a target gene of miR-155-5p. Here, the present study aims to explore the role of TAM-derived exosomal miR-155-5p by regulating GREM1 in intracranial aneurysm (IA). The collected results showed that GREM1 was down-regulated in IA, while miR-155-5p was up-regulated in TAM-derived exosomes. Smooth muscle cells (SMCs) were co-cultured with TAMs or exposed to exosomes derived from TAMs transfected with either miR-155-5p mimic or miR-155-5p inhibitor for exploring their roles in proliferation and migration of SMCs in vitro. Accordingly, in vitro experiments showed that TAM-derived exosomal miR-155-5p could promote proliferation and migration of SMCs by targeting GREM1. The effects of TAM-derived exosomal miR-155-5p on IA formation and TAM activation and infiltration by regulation of GREM1 in vivo were measured in IA rats injected with exosomes or those from TAMs transfected with miR-155-5p inhibitor. In vivo experimental results consistently confirmed that TAM-derived exosomes carrying miR-155-5p promoted IA formation and TAM activation and infiltration. In conclusion, TAM-derived exosomal miR-155-5p promotes IA formation via GREM1, which points to miR-155-5p as a possible therapeutic target for IA.


2020 ◽  
Author(s):  
Lungwani Muungo

Upregulation of EBAG9 expression has been observed in severalmalignant tumors such as advanced breast and prostate cancers,indicating that EBAG9 may contribute to tumor proliferation. Inthe present study, we assess the role of EBAG9 in bladder cancer.We generated human bladder cancer EJ cells stably expressingFLAG-tagged EBAG9 (EJ-EBAG9) or empty vector (EJ-vector),and investigated whether EBAG9 overexpression modulates cellgrowth and migration in vitro as well as the in vivo tumor formationof EJ transfectants in xenograft models of BALB/c nude mice.EBAG9 overexpression promoted EJ cell migration, while theeffect of EBAG9 to cultured cell growth was rather minimal.Tumorigenic experiments in nude mice showed that the size of EJEBAG9-derived tumors was significantly larger than EJ-vectorderivedtumors. Loss-of-function study for EBAG9 using smallinterfering RNA (siRNA) in xenografts with parental EJ cellsshowed that the intra-tumoral injection of EBAG9 siRNA markedlyreduced the EJ tumor formation compared with controlsiRNA. Furthermore, immunohistochemical study for EBAG9expression was performed in 60 pathological bladder cancer specimens.Intense and diffuse cytoplasmic immunostaining wasobserved in 45% of the bladder cancer cases. Positive EBAG9immunoreactivity was closely correlated with poor prognosis ofthe patients (p 5 0.0001) and it was an independent prognosticpredictor for disease-specific survival in multivariate analysis(p 5 0.003). Our results indicate that EBAG9 would be a crucialregulator of tumor progression and a potential prognostic markerfor bladder cancer.


2017 ◽  
Vol 44 (2) ◽  
pp. 554-566 ◽  
Author(s):  
Qian Yu ◽  
Xu Han ◽  
Da-Li Tian

Background/Aims: ATP-binding cassette transporter E1 (ABCE1), a unique ABC superfamily member that bears two Fe-S clusters, is essential for metastatic progression in lung cancer. Fe-S clusters within ABCE1 are crucial for ribosome dissociation and translation reinitiation; however, whether these clusters promote tumor proliferation and migration is unclear. Methods: The interaction between ABCE1 and β-actin was confirmed using GST pull-down. The lung adenocarcinoma (LUAD) cell line A549 was transduced with lentiviral packaging vectors overexpressing either wild-type ABCE1 or ABCE1 with Fe-S cluster deletions (ΔABCE1). The role of Fe-S clusters in the viability and migration of cancer cells was evaluated using clonogenic, MTT, Transwell and wound healing assays. Cytoskeletal rearrangement was determined using immunofluorescent techniques. Results: Fe-S clusters were the key domains in ABCE1 involved in binding to β-actin. The proliferative and migratory capacity increased in cells overexpressing ABCE1. However, the absence of Fe-S clusters reversed these effects. A549 cells overexpressing ABCE1 exhibited irregular morphology and increased levels of cytoskeletal polymerization as indicated by the immunofluorescence images. In contrast, cells expressing the Fe-S cluster deletion mutant presented opposing effects. Conclusion: These results demonstrate the indispensable role of Fe-S clusters when ABCE1 participates in the proliferation and migration of LUADs by interacting with β-actin. The Fe-S clusters of ABCE1 may be potential targets for the prevention of lung cancer metastasis.


2018 ◽  
Vol 115 (37) ◽  
pp. E8660-E8667 ◽  
Author(s):  
Abu Shufian Ishtiaq Ahmed ◽  
Kunzhe Dong ◽  
Jinhua Liu ◽  
Tong Wen ◽  
Luyi Yu ◽  
...  

In response to vascular injury, vascular smooth muscle cells (VSMCs) may switch from a contractile to a proliferative phenotype thereby contributing to neointima formation. Previous studies showed that the long noncoding RNA (lncRNA) NEAT1 is critical for paraspeckle formation and tumorigenesis by promoting cell proliferation and migration. However, the role of NEAT1 in VSMC phenotypic modulation is unknown. Herein we showed that NEAT1 expression was induced in VSMCs during phenotypic switching in vivo and in vitro. Silencing NEAT1 in VSMCs resulted in enhanced expression of SM-specific genes while attenuating VSMC proliferation and migration. Conversely, overexpression of NEAT1 in VSMCs had opposite effects. These in vitro findings were further supported by in vivo studies in which NEAT1 knockout mice exhibited significantly decreased neointima formation following vascular injury, due to attenuated VSMC proliferation. Mechanistic studies demonstrated that NEAT1 sequesters the key chromatin modifier WDR5 (WD Repeat Domain 5) from SM-specific gene loci, thereby initiating an epigenetic “off” state, resulting in down-regulation of SM-specific gene expression. Taken together, we demonstrated an unexpected role of the lncRNA NEAT1 in regulating phenotypic switching by repressing SM-contractile gene expression through an epigenetic regulatory mechanism. Our data suggest that NEAT1 is a therapeutic target for treating occlusive vascular diseases.


Author(s):  
Yuanyuan Han ◽  
Qixin Chen ◽  
Lili Zhang ◽  
Waruna Lakmal Dissanayaka

ObjectivesPost-implantation survival and timely vascularization of stem-cell based constructs are critical factors in achieving successful outcomes in tissue regeneration approaches. Hypoxia inducible factor-1α (HIF-1α) is known to mediate adaptive functions to ischemic stress in many different cell types. The current study aimed to explore the role of HIF-1α in post-implantation survival and angio-/vasculogenesis of stem cells from human exfoliated deciduous teeth (SHED).MethodsHIF-1α in SHED was suppressed using siRNA or chemical inhibitor (YC-1) and used in Matrigel plug assay conducted on severe combined immunodeficient mice. The plugs were retrieved on day 3 or 7 post-injection and analyzed for hypoxia status, ki67 expression, DNA fragmentation (TUNEL), cellularity, and vascularization by histology and immunohistochemistry for CD31, HIF-1α, pyruvate dehydrogenase kinase-1 (PDK1), hexokinase 2 (HK2), and glucose transporter 1 (Glut1). Cell viability of HIF-1α silenced SHED under different stress conditions (hypoxia, H2O2, and low glucose) in vitro was measured by CCK-8 assay. CM-H2DCFDA and MitoSOX Red were used to detect cellular and mitochondrial reactive oxygen species (ROS) levels, respectively. PDK1, HK2, and Glut1 expression were measured by western blotting and immunofluorescence. Secretory protein levels of vascular endothelial growth factor (VEGF) and the respective paracrine effects on endothelial cell proliferation and migration were detected by ELISA, CCK-8 assay, and trans-well assay, respectively.ResultsHistological analysis of Matrigel plugs showed significantly reduced cell survival in HIF-1α silenced or chemically inhibited SHED groups, which could be attributed to diminished metabolic adaptations as shown by decreased PDK1, HK2, and Glut1 expression. HIF-1α inhibition in SHED also resulted in significantly low blood vessel formation as observed by a low number of perfused and non-perfused vessels of human or mouse CD31 origin. The viability of HIF-1α silenced SHED was significantly affected under hypoxia, H2O2, and low-glucose conditions in vitro, which was reflected in increased cytoplasmic and mitochondrial ROS levels. Significantly reduced levels of VEGF in HIF-1α silenced SHED resulted in decreased paracrine angiogenic effects as shown by low proliferation and migration of endothelial cells.ConclusionHIF-1α plays an indispensable role in post-implantation survival and angio-/vasculogenic properties of SHED by maintaining ROS homeostasis, inducing metabolic adaptations, and VEGF secretion.


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