The HIF1α/JMY pathway promotes glioblastoma stem-like cell invasiveness after irradiation.
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ABSTRACT:
SUBMITTER: Gauthier LR
PROVIDER: S-EPMC7603339 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Interferon-induced transmembrane protein 3 (IFITM3) has been previously verified to be an endosomal protein that prevents viral infection. Recent findings suggested IFITM3 as a key factor in tumor invasion and progression. To clarify the role and molecular mechanism of IFITM3 in Glioblastoma multiforme (GBM) progression, we investigated the expression of IFITM3 in glioma datasets culled from The Cancer Genome Atlas (TCGA) and Chinese Glioma Genome Atlas (CGGA). Primary GBM stem cells (GSCs) were cultured and identified in vitro. Loss-of-function and gain-of-function experiments were established by using shRNAs and lentiviral vectors targeting IFITM3. Co-culture system of GSCs and vascular endothelial cells was constructed in a Transwell chamber. Tube formation and spheroid-based angiogenesis assays were performed to determine the angiogenic capacity of endothelial cells. Results revealed that IFITM3 is elevated in GBM samples and predictive of adverse outcome. Mechanistically, GSCs-derived IFITM3 causes activation of Jak2/STAT3 signaling and leads to robust secretion of bFGF into tumor environment, which eventually results in enhanced angiogenesis. Taken together, these evidence indicated IFITM3 as an essential factor in GBM angiogenesis. Our findings provide a new insight into mechanism by which IFITM3 modulates GBM angiogenesis.
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Project description:BackgroundThe plant homeodomain (PHD) finger protein 14 (PHF14) is a vital member of PHD finger protein families. Abnormal expression of PHF14 has been identified in various cancers and is known to be implicated in the pathogenesis of tumors. This study investigates the role and the underlying mechanisms of PHF14 in GBM (glioblastoma multiforme).MethodsTissue microarrays and public databases interrogation were used to explore the relationship between the expression of PHF14 and GBM. Three stable PHF14-silenced cell lines (U251, U87MG and A172) were constructed to assess the biological functions changes of GBM cells in vitro. In addition, tumorigenicity in vivo was also performed using U87MG cell line. To understand the mechanism of action of PHF14, RNA-Seq, qRT-PCR, Western blot, IC50 assay and subsequent pathway analysis were performed.ResultsOur results showed that the expression of PHF14 was upregulated in glioma, especially in GBM. Overexpression of PHF14 translated to poor prognosis in glioma patients. In vitro assays revealed that silencing expression of PHF14 in glioma cells inhibited migration, invasiveness and proliferation and promoted cell apoptosis. Animal assay further confirmed that over-expression of PHF14 was a dismal prognostic factor. Analysis based on RNA-Seq suggested a PHF14-dependent regulation of Wnt signaling networks, which was further validated by qRT-PCR, Western blot and IC50 analysis. In addition, the mRNA expression of several key markers of EMT (epithelial-mesenchymal transition) and angiogenesis was found to change upon PHF14 silencing.ConclusionsOur data provide a new insight into the biological significance of PHF14 in glioma and its potential application in therapy and diagnosis.
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Project description:"Glioma Stem Cells" (GSCs) are known to play a role in glioblastoma (GBM) recurrence. Homologous recombination (HR) defects and cell cycle checkpoint abnormalities can contribute concurrently to the radioresistance of GSCs. DNA repair protein RAD51 homolog 1 (RAD51) is a crucial protein for HR and its inhibition has been shown to sensitize GSCs to irradiation. The aim of this study was to examine the consequences of ionizing radiation (IR) for cell cycle progression in GSCs. In addition, we intended to assess the potential effect of RAD51 inhibition on cell cycle progression. Five radiosensitive GSC lines and five GSC lines that were previously characterized as radioresistant were exposed to 4Gy IR, and cell cycle analysis was done by fluorescence-activated cell sorting (FACS) at 24, 48, 72, and 96 h with or without RAD51 inhibitor. Following 4Gy IR, all GSC lines presented a significant increase in G2 phase at 24 h, which was maintained over 72 h. In the presence of RAD51 inhibitor, radioresistant GSCs showed delayed G2 arrest post-irradiation for up to 48 h. This study demonstrates that all GSCs can promote G2 arrest in response to radiation-induced DNA damage. However, following RAD51 inhibition, the cell cycle checkpoint response differed. This study contributes to the characterization of the radioresistance mechanisms of GSCs, thereby supporting the rationale of targeting RAD51-dependent repair pathways in view of radiosensitizing GSCs.
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Project description:Chromatin remodeler proteins exert an important function in promoting dynamic modifications in the chromatin architecture, performing a central role in regulating gene transcription. Deregulation of these molecular machines may lead to striking perturbations in normal cell function. The CHD7 gene is a member of the chromodomain helicase DNA-binding family and, when mutated, has been shown to be the cause of the CHARGE syndrome, a severe developmental human disorder. Moreover, CHD7 has been described to be essential for neural stem cells and it is also highly expressed or mutated in a number of human cancers. However, its potential role in glioblastoma has not yet been tested. Here, we show that CHD7 is up-regulated in human glioma tissues and we demonstrate that CHD7 knockout (KO) in LN-229 glioblastoma cells suppresses anchorage-independent growth and spheroid invasion in vitro. Additionally, CHD7 KO impairs tumor growth and increases overall survival in an orthotopic mouse xenograft model. Conversely, ectopic overexpression of CHD7 in LN-428 and A172 glioblastoma cell lines increases cell motility and invasiveness in vitro and promotes LN-428 tumor growth in vivo. Finally, RNA-seq analysis revealed that CHD7 modulates a specific transcriptional signature of invasion-related target genes. Further studies should explore clinical-translational implications for glioblastoma treatment.
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Project description:Glioblastoma (GBM) is characterized by a particularly invasive phenotype, supported by oncogenic signals from the fibroblast growth factor (FGF)/ FGF receptor (FGFR) network. However, a possible role of FGFR4 remained elusive so far. Several transcriptomic glioma datasets were analyzed. An extended panel of primary surgical specimen-derived and immortalized GBM (stem)cell models and original tumor tissues were screened for FGFR4 expression. GBM models engineered for wild-type and dominant-negative FGFR4 overexpression were investigated regarding aggressiveness and xenograft formation. Gene set enrichment analyses of FGFR4-modulated GBM models were compared to patient-derived datasets. Despite widely absent in adult brain, FGFR4 mRNA was distinctly expressed in embryonic neural stem cells and significantly upregulated in glioblastoma. Pronounced FGFR4 overexpression defined a distinct GBM patient subgroup with dismal prognosis. Expression levels of FGFR4 and its specific ligands FGF19/FGF23 correlated both in vitro and in vivo and were progressively upregulated in the vast majority of recurrent tumors. Based on overexpression/blockade experiments in respective GBM models, a central pro-oncogenic function of FGFR4 concerning viability, adhesion, migration, and clonogenicity was identified. Expression of dominant-negative FGFR4 resulted in diminished (subcutaneous) or blocked (orthotopic) GBM xenograft formation in the mouse and reduced invasiveness in zebrafish xenotransplantation models. In vitro and in vivo data consistently revealed distinct FGFR4 and integrin/extracellular matrix interactions. Accordingly, FGFR4 blockade profoundly sensitized FGFR4-overexpressing GBM models towards integrin/focal adhesion kinase inhibitors. Collectively, FGFR4 overexpression contributes to the malignant phenotype of a highly aggressive GBM subgroup and is associated with integrin-related therapeutic vulnerabilities.
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Project description:Cancer cells induce a set of adaptive response pathways to survive in the face of stressors due to inadequate vascularization. One such adaptive pathway is the unfolded protein (UPR) or endoplasmic reticulum (ER) stress response mediated in part by the ER-localized transmembrane sensor IRE1 (ref. 2) and its substrate XBP1 (ref. 3). Previous studies report UPR activation in various human tumours, but the role of XBP1 in cancer progression in mammary epithelial cells is largely unknown. Triple-negative breast cancer (TNBC)--a form of breast cancer in which tumour cells do not express the genes for oestrogen receptor, progesterone receptor and HER2 (also called ERBB2 or NEU)--is a highly aggressive malignancy with limited treatment options. Here we report that XBP1 is activated in TNBC and has a pivotal role in the tumorigenicity and progression of this human breast cancer subtype. In breast cancer cell line models, depletion of XBP1 inhibited tumour growth and tumour relapse and reduced the CD44(high)CD24(low) population. Hypoxia-inducing factor 1α (HIF1α) is known to be hyperactivated in TNBCs. Genome-wide mapping of the XBP1 transcriptional regulatory network revealed that XBP1 drives TNBC tumorigenicity by assembling a transcriptional complex with HIF1α that regulates the expression of HIF1α targets via the recruitment of RNA polymerase II. Analysis of independent cohorts of patients with TNBC revealed a specific XBP1 gene expression signature that was highly correlated with HIF1α and hypoxia-driven signatures and that strongly associated with poor prognosis. Our findings reveal a key function for the XBP1 branch of the UPR in TNBC and indicate that targeting this pathway may offer alternative treatment strategies for this aggressive subtype of breast cancer.
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Project description:Previous studies have suggested that hypoxic responses are regulated by hypoxia-inducible factors (HIFs), which in turn promote the malignant progression of glioblastoma (GBM) by inhibiting apoptosis and increasing proliferation; these events lead to a poor prognosis of GBM patients. However, there are still no HIF-targeted therapies for the treatment of GBM. We have conducted series of experiments and discovered that GBM cells exhibit features indicative of malignant progression and are present in a hypoxic environment. Knocking out HIF1α or HIF2α alone resulted in no significant change in cell proliferation and cell cycle progression in response to acute hypoxia, but cells showed inhibition of stemness expression and chemosensitization to temozolomide (TMZ) treatment. However, simultaneously knocking out HIF1α and HIF2α inhibited cell cycle arrest and promoted proliferation with decreased stemness, making GBM cells more sensitive to chemotherapy, which could improve patient prognosis. Thus, HIF1α and HIF2α regulate each other with negative feedback. In addition, HIF1α and HIF2α are upstream regulators of epidermal growth factor (EGF), which controls the malignant development of GBM through the EGFR-PI3K/AKT-mTOR-HIF1α signalling pathway. In brief, the HIF1α/HIF2α-EGF/EGFR-PI3K/AKT-mTOR-HIF1α signalling axis contributes to the growth of GBM through a positive feedback mechanism. Finally, HIF1α and HIF2α regulate Sox2 and Klf4, contributing to stemness expression and inducing cell cycle arrest, thus increasing malignancy in GBM. In summary, HIF1α and HIF2α regulate glioblastoma malignant progression through the EGFR-PI3K/AKT pathway via a positive feedback mechanism under the effects of Sox2 and Klf4, which provides a new tumour development model and strategy for glioblastoma treatment.
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Project description:BackgroundGlioblastoma stem cells (GSCs) are a subpopulation of glioblastoma (GBM) cells that are critical for tumor invasion and treatment resistance. However, little is known about the function and mechanism of tripartite motif-containing 24 (TRIM24) in GSCs.MethodsImmunofluorescence, flow cytometry, and western blot analyses were used to evaluate TRIM24 and cluster of differentiation (CD)133 expression profiles in GBM surgical specimens and GSC tumorspheres. Different TRIM24 expression levels in patients' tumors, as measured by both immunohistochemistry and western blot, were related to their corresponding MRI data. Wound healing, Matrigel invasion, and xenograft immunohistochemistry were conducted to determine GBM cell invasion.ResultsWe identified that TRIM24 was coexpressed with CD133 and Nestin in GBM tissues and tumorsphere cells. Limiting dilution assays and xenotransplantation experiments illustrated that knockdown of TRIM24 expression reduced GSC self-renewal capacity and invasive growth. TRIM24 expression levels were positively associated with the volumes of peritumoral T2 weighted image abnormality. Rescue experiments indicated TRIM24 participation in GBM infiltrative dissemination. Chromatin immunoprecipitation, reporter gene assay, PCR, western blot, and immunohistochemistry demonstrated that TRIM24 activated the expression of the pluripotency transcription factor sex determining region Y-box 2 (Sox2) to regulate GBM stemness and invasion in vitro and in vivo. Finally, the close relationship between TRIM24 and Sox2 was validated by testing samples enrolled in our study and exploring external databases.ConclusionsOur findings uncover essential roles of the TRIM24-Sox2 axis in GBM stemness and invasiveness, suggesting TRIM24 as a potential target for effective GBM management.
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