scholarly journals NF1 regulates mesenchymal glioblastoma plasticity and aggressiveness through the AP-1 transcription factor FOSL1

2019 ◽  
Author(s):  
Carolina Marques ◽  
Thomas Unterkircher ◽  
Paula Kroon ◽  
Annalisa Izzo ◽  
Yuliia Dramaretska ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Stem Cell ◽  
Mapk Pathway ◽  
Neurofibromatosis Type ◽  
Gene Signature ◽  
Negative Regulator ◽  
Tumor Stem Cell ◽  
Stem Cell Lines ◽  
Mesenchymal Transformation

AbstractThe molecular basis underlying Glioblastoma (GBM) heterogeneity and plasticity are not fully understood. Using transcriptomic data of patient-derived brain tumor stem cell lines (BTSCs), classified based on GBM-intrinsic signatures, we identify the AP-1 transcription factor FOSL1 as a key regulator of the mesenchymal (MES) subtype. We provide a mechanistic basis to the role of the Neurofibromatosis type 1 gene (NF1), a negative regulator of the RAS/MAPK pathway, in GBM mesenchymal transformation through the modulation of FOSL1 expression. Depletion of FOSL1 in NF1-mutant human BTSCs and Kras-mutant mouse neural stem cells results in loss of the mesenchymal gene signature, reduction in stem cell properties and in vivo tumorigenic potential. Our data demonstrate that FOSL1 controls GBM plasticity and aggressiveness in response to NF1 alterations.

scholarly journals NF1 regulates mesenchymal glioblastoma plasticity and aggressiveness through the AP-1 transcription factor FOSL1

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Carolina Marques ◽  
Thomas Unterkircher ◽  
Paula Kroon ◽  
Barbara Oldrini ◽  
Annalisa Izzo ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Stem Cell ◽  
Mapk Pathway ◽  
Neurofibromatosis Type ◽  
Gene Signature ◽  
Negative Regulator ◽  
Tumor Stem Cell ◽  
Human Patient ◽  
Mesenchymal Transformation

The molecular basis underlying glioblastoma (GBM) heterogeneity and plasticity is not fully understood. Using transcriptomic data of human patient-derived brain tumor stem cell lines (BTSCs), classified based on GBM-intrinsic signatures, we identify the AP-1 transcription factor FOSL1 as a key regulator of the mesenchymal (MES) subtype. We provide a mechanistic basis to the role of the neurofibromatosis type 1 gene (NF1), a negative regulator of the RAS/MAPK pathway, in GBM mesenchymal transformation through the modulation of FOSL1 expression. Depletion of FOSL1 in NF1-mutant human BTSCs and Kras-mutant mouse neural stem cells results in loss of the mesenchymal gene signature and reduction in stem cell properties and in vivo tumorigenic potential. Our data demonstrate that FOSL1 controls GBM plasticity and aggressiveness in response to NF1 alterations.

scholarly journals Pak1 regulates multiple c-Kit mediated Ras-MAPK gain-in-function phenotypes in Nf1+/− mast cells

Blood ◽  
2008 ◽  
Vol 112 (12) ◽  
pp. 4646-4654 ◽  
Author(s):  
Andrew S. McDaniel ◽  
Jayme D. Allen ◽  
Su-Jung Park ◽  
Zahara M Jaffer ◽  
Elizabeth G. Michels ◽  
...  
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Mapk Pathway ◽  
Genetic Disorder ◽  
Neurofibromatosis Type ◽  
Mapk Signaling ◽  
Tumor Formation ◽  
Negative Regulator ◽  
P21 Activated Kinase

Abstract Neurofibromatosis type 1 (NF1) is a common genetic disorder caused by mutations in the NF1 locus, which encodes neurofibromin, a negative regulator of Ras. Patients with NF1 develop numerous neurofibromas, which contain many inflammatory mast cells that contribute to tumor formation. Subsequent to c-Kit stimulation, signaling from Ras to Rac1/2 to the MAPK pathway appears to be responsible for multiple hyperactive mast cell phenotypes; however, the specific effectors that mediate these functions remain uncertain. p21-activated kinase 1 (Pak1) is a downstream mediator of Rac1/2 that has been implicated as a positive regulator of MAPK pathway members and is a modulator of cell growth and cytoskeletal dynamics. Using an intercross of Pak 1−/− mice with Nf1+/− mice, we determined that Pak1 regulates hyperactive Ras-dependent proliferation via a Pak1/Erk pathway, whereas a Pak1/p38 pathway is required for the increased migration in Nf1+/− mast cells. Furthermore, we confirmed that loss of Pak1 corrects the dermal accumulation of Nf1+/− mast cells in vivo to levels found in wild-type mice. Thus, Pak1 is a novel mast cell mediator that functions as a key node in the MAPK signaling network and potential therapeutic target in NF1 patients.

scholarly journals Semaphorin 3A mediated brain tumor stem cell proliferation and invasion in EGFRviii mutant gliomas

BMC Cancer ◽  
2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Dominique M. O. Higgins ◽  
Maisel Caliva ◽  
Mark Schroeder ◽  
Brett Carlson ◽  
Pavan S. Upadhyayula ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Stem Cell ◽  
Brain Tumor ◽  
Propidium Iodide ◽  
Tumor Stem Cell ◽  
Semaphorin 3A ◽  
Brain Tumor Stem Cell ◽  
Proliferation And Invasion ◽  
Invasion Assays

Abstract Background Glioblastoma multiforme (GBM) is the most common primary brain tumor in adults, with a median survival of approximately 15 months. Semaphorin 3A (Sema3A), known for its axon guidance and antiangiogenic properties, has been implicated in GBM growth. We hypothesized that Sema3A directly inhibits brain tumor stem cell (BTSC) proliferation and drives invasion via Neuropilin 1 (Nrp1) and Plexin A1 (PlxnA1) receptors. Methods GBM BTSC cell lines were assayed by immunostaining and PCR for levels of Semaphorin 3A (Sema3A) and its receptors Nrp1 and PlxnA1. Quantitative BrdU, cell cycle and propidium iodide labeling assays were performed following exogenous Sema3A treatment. Quantitative functional 2-D and 3-D invasion assays along with shRNA lentiviral knockdown of Nrp1 and PlxnA1 are also shown. In vivo flank studies comparing tumor growth of knockdown versus control BTSCs were performed. Statistics were performed using GraphPad Prism v7. Results Immunostaining and PCR analysis revealed that BTSCs highly express Sema3A and its receptors Nrp1 and PlxnA1, with expression of Nrp1 in the CD133 positive BTSCs, and absence in differentiated tumor cells. Treatment with exogenous Sema3A in quantitative BrdU, cell cycle, and propidium iodide labeling assays demonstrated that Sema3A significantly inhibited BTSC proliferation without inducing cell death. Quantitative functional 2-D and 3-D invasion assays showed that treatment with Sema3A resulted in increased invasion. Using shRNA lentiviruses, knockdown of either NRP1 or PlxnA1 receptors abrogated Sema3A antiproliferative and pro-invasive effects. Interestingly, loss of the receptors mimicked Sema3A effects, inhibiting BTSC proliferation and driving invasion. Furthermore, in vivo studies comparing tumor growth of knockdown and control infected BTSCs implanted into the flanks of nude mice confirmed the decrease in proliferation with receptor KD. Conclusions These findings demonstrate the importance of Sema3A signaling in GBM BTSC proliferation and invasion, and its potential as a therapeutic target.

scholarly journals Cisplatin-mediated activation of glucocorticoid receptor induces platinum resistance via MAST1

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Chaoyun Pan ◽  
JiHoon Kang ◽  
Jung Seok Hwang ◽  
Jie Li ◽  
Austin C. Boese ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Glucocorticoid Receptor ◽  
Tumor Growth ◽  
Nuclear Translocation ◽  
Mapk Pathway ◽  
Underlying Mechanism ◽  
Patient Treatment ◽  
Platinum Resistance ◽  
Platinum Based Chemotherapy

AbstractAgonists of glucocorticoid receptor (GR) are frequently given to cancer patients with platinum-containing chemotherapy to reduce inflammation, but how GR influences tumor growth in response to platinum-based chemotherapy such as cisplatin through inflammation-independent signaling remains largely unclear. Combined genomics and transcription factor profiling reveal that MAST1, a critical platinum resistance factor that reprograms the MAPK pathway, is upregulated upon cisplatin exposure through activated transcription factor GR. Mechanistically, cisplatin binds to C622 in GR and recruits GR to the nucleus for its activation, which induces MAST1 expression and consequently reactivates MEK signaling. GR nuclear translocation and MAST1 upregulation coordinately occur in patient tumors collected after platinum treatment, and align with patient treatment resistance. Co-treatment with dexamethasone and cisplatin restores cisplatin-resistant tumor growth, whereas addition of the MAST1 inhibitor lestaurtinib abrogates tumor growth while preserving the inhibitory effect of dexamethasone on inflammation in vivo. These findings not only provide insights into the underlying mechanism of GR in cisplatin resistance but also offer an effective alternative therapeutic strategy to improve the clinical outcome of patients receiving platinum-based chemotherapy with GR agonists.

scholarly journals A Potential Antitumor Effect of Dendritic Cells Fused with Cancer Stem Cells in Hepatocellular Carcinoma

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Ye-Bin Pang ◽  
Jian He ◽  
Bi-Yu Cui ◽  
Sheng Xu ◽  
Xi-Lei Li ◽  
...  
Keyword(s):  
Stem Cells ◽  
Dendritic Cells ◽  
Stem Cell ◽  
Tumor Cells ◽  
Hepg2 Cells ◽  
Cytotoxicity Assay ◽  
Tumor Stem Cell ◽  
Fusion Cell

HCC stem cells were reported as posttreatment residual tumor cells that play a pivotal role in tumor relapse. Fusing dendritic cells (DCs) with tumor cells represents an ideal approach to effectively activate the antitumor immunity in vivo. DC/HCC stem cell vaccine provides a potential strategy to generate polyclonal immune response to multiple tumor stem cell antigens including those yet to be unidentified. To assess the potential capacity of DC/HCC stem cell vaccines against HCC, CD90+HepG2 cells were sorted from the HCC cell line HepG2. DC and CD90+HepG2 and DC and HepG2 fused cells were induced by polyethylene glycol (PEG). The influence of fusion cells on proliferation and immunological function transformation of lymphocytes was assessed by FCM and ELISA assay, respectively. The cytotoxicity assay of specific fusion cell-induced CTLs against HepG2 was conducted by CytoTox 96 Non-Radioactive Cytotoxicity Assay kit in vitro. At last, the prevention of HCC formation in vivo was described in a mouse model. The results of FCM analysis showed that the proportion of CD90+HepG2 cells in the spheral CD90+HepG2 enriched by suspension sphere culture was ranging from 98.7% to 99.5%, and 57.1% CD90+HepG2/DC fused cells were successfully constructed. The fusion cells expressed a higher level of costimulatory molecules CD80, CD83, CD86, and MHC-I and MHC-II molecules HLA-ABC and HLA-DR than did immature DCs (P<0.05). And the functional analysis of fusion cell-induced CTLs also illustrated that CD90+HepG2/DC fusion cells showed a greater capacity to activate proliferation of lymphocytes in vitro (P<0.05). The CD90+HepG2/DC-activated CTLs had a specific killing ability against CD90+HepG2 cells in vivo. These results suggested that CD90+HepG2/DC fusion cells could efficiently stimulate T lymphocytes to generate specific CTLs targeting CD90+HepG2 cells. It might be a promising strategy of immunotherapy for HCC.

scholarly journals BTB Protein Keap1 Targets Antioxidant Transcription Factor Nrf2 for Ubiquitination by the Cullin 3-Roc1 Ligase

2005 ◽  
Vol 25 (1) ◽  
pp. 162-171 ◽  
Author(s):  
Manabu Furukawa ◽  
Yue Xiong
Keyword(s):  
Transcription Factor ◽  
Ring Finger ◽  
Negative Regulator ◽  
Protein Accumulation ◽  
Protein Motif ◽  
Terminal Domain ◽  
Catalytic Function ◽  
Cullin 3

ABSTRACT The concentrations and functions of many eukaryotic proteins are regulated by the ubiquitin pathway, which consists of ubiquitin activation (E1), conjugation (E2), and ligation (E3). Cullins are a family of evolutionarily conserved proteins that assemble by far the largest family of E3 ligase complexes. Cullins, via a conserved C-terminal domain, bind with the RING finger protein Roc1 to recruit the catalytic function of E2. Via a distinct N-terminal domain, individual cullins bind to a protein motif present in multiple proteins to recruit specific substrates. Cullin 3 (Cul3), but not other cullins, binds directly with BTB domains to constitute a potentially large number of BTB-CUL3-ROC1 E3 ubiquitin ligases. Here we report that the human BTB-Kelch protein Keap1, a negative regulator of the antioxidative transcription factor Nrf2, binds to CUL3 and Nrf2 via its BTB and Kelch domains, respectively. The KEAP1-CUL3-ROC1 complex promoted NRF2 ubiquitination in vitro and knocking down Keap1 or CUL3 by short interfering RNA resulted in NRF2 protein accumulation in vivo. We suggest that Keap1 negatively regulates Nrf2 function in part by targeting Nrf2 for ubiquitination by the CUL3-ROC1 ligase and subsequent degradation by the proteasome. Blocking NRF2 degradation in cells expressing both KEAP1 and NRF2 by either inhibiting the proteasome activity or knocking down Cul3, resulted in NRF2 accumulation in the cytoplasm. These results may reconcile previously observed cytoplasmic sequestration of NRF2 by KEAP1 and suggest a possible regulatory step between KEAP1-NRF2 binding and NRF2 degradation.

Attenuated Acute Graft-Versus-Host Disease Following Allogeneic Stem Cell Transplantation In the Absence of RORγt.

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 3742-3742
Author(s):  
LeShara M Fulton ◽  
Michael J Carlson ◽  
James Coghill ◽  
Michelle L. West ◽  
Angela Panoskaltisis-Mortari ◽  
...  
Keyword(s):  
T Cells ◽  
Transcription Factor ◽  
Stem Cell ◽  
T Cell ◽  
Stem Cell Transplantation ◽  
Graft Versus Host Disease ◽  
Allogeneic Stem Cell Transplantation ◽  
Graft Versus Host ◽  
Donor T Cells

Abstract Abstract 3742 CD4+ T helper (Th) cells play a critical role in the development of Graft-versus-Host Disease (GvHD). The relative contributions of particular Th subsets to GVHD pathogenesis, however, are incompletely understood. In order to clarify the contribution of the Th17 subset to GVHD induction, we made use of mice knocked out at the RORgt locus (RORgt−/−), a transcription factor crucial for Th17 polarization. Methods: Haplotype matched and complete MHC mismatched murine HSCT models were used. For the haploidentical model C57BL/6 (H-2b, B6) mice served as donors while C57BL/6 × DBA2 F1 (H-2bxd, B6D2) mice functioned as recipients. Effector T cells (Teffs) were isolated from the spleens of wild type (WT) B6 and RORgt knockout mice backcrossed 7–8 generations onto a B6 background. B6D2 mice were lethally irradiated with 900 rads on day -1 and injected intravenously with 4 × 106 Teffs from WT or RORgt−/− mice supplemented with 3 × 106 WT T cell depleted bone marrow cells (TCD BM) on day 0. For the completely MHC mismatched model, BALB/c mice (H-2d) were lethally irradiated with 800 rads on day -1 and administered 5 × 105 WT or RORgt−/− Teffs supplemented with 5 × 106 B6 TCD BM on day 0. Results: B6D2 mice that received RORgt−/− Teffs displayed significantly attenuated GvHD, recovering from weight loss by day +31 and demonstrating 100% survival on day +60. Conversely, mice that received WT Teffs showed intense disease progression with 100% mortality by day +31 (Figure A, p<0.0001 for survival comparison between WT and RORgt−/− recipients using Fisher's exact test). Similar results were seen using the completely MHC mismatched model, with superior overall survival noted in those animals receiving RORgt −/− Teffs (put in p value here). Recipients of RORgt −/− T cells demonstrated statistically significant decreased TNF in serum compared to WT recipients (Figure B, p=0.001 comparing WT and RORgt−/− recipients using student's t test). Interestingly, despite the decreased severity of GvHD, serum concentrations of IFN-g were increased in recipients transplanted with RORgt −/− T cells. Chimerism studies post-transplant revealed complete donor reconstitution in recipients of both RORgt−/− and WT Teffs. Donor Teffs isolated from recipient livers post-transplant consistently demonstrated an activated phenotype, with low L selectin and high CD25 expression. Conclusions: T cell expression of the Th17 transcription factor, RORgt, is critical for the development of lethal GvHD following allogeneic stem cell transplantation in both the haploidentical and MHC complete mismatch models. GvHD attenuation in the absence of RORgt is not the result of an inability for donor T cells to undergo activation or to engraft in vivo. Interestingly, the absence of RORgt from donor T cells led to enhanced IFN-g in serum. Thus, in vivo, the Th17 pathway is critical for the induction of GvHD. Disclosures: No relevant conflicts of interest to declare.

scholarly journals LncRNA LIPE-AS1 Predicts Poor Survival of Cervical Cancer and Promotes Its Proliferation and Migration via Modulating miR-195-5p/MAPK Pathway

2021 ◽  
Vol 11 ◽  
Author(s):  
Jie Zhang ◽  
Pinping Jiang ◽  
Shoyu Wang ◽  
Wenjun Cheng ◽  
Shilong Fu
Keyword(s):  
Cervical Cancer ◽  
Western Blot ◽  
Signaling Pathway ◽  
Mapk Pathway ◽  
Mapk Signaling ◽  
Tumor Formation ◽  
Mapk Signaling Pathway ◽  
Rt Pcr ◽  
Mesenchymal Transformation

Aims: A growing number of studies have unveiled that long non-coding RNA (lncRNA) is conductive to cervical cancer (CC) development. However, the effect of LIPE-AS1 is remained to be studied in CC.Main Methods: Reverse transcription-polymerase chain reaction (RT-PCR) was employed to measure LIPE-AS1 expression in CC tissues and the adjacent normal tissues. Additionally, we conducted gain- and loss-of functional experiments of LIPE-AS1 and adopted CCK8 assay, BrdU assay, and in vivo tumor formation experiment to test the proliferation of CC cells (HCC94 and HeLa). Besides, the apoptosis, invasion, and epithelial-mesenchymal transformation (EMT) of CC cells were estimated using flow cytometry, transwell assay, and western blot, respectively. Further, LIPE-AS1 downstream targets were analyzed through bioinformatics, and the binding relationships between LIPE-AS1 and miR-195-5p were verified via dual-luciferase activity experiment and RNA Protein Immunoprecipitation (RIP) assay. Moreover, rescue experiments were conducted to confirm the effects of LIPE-AS1 and miR-195-5p in regulating CC development and the expressions of MAPK signaling pathway related proteins were detected by RT-PCR, western blot, and immunofluorescence.Key Findings: LIPE-AS1 was over-expressed in CC tissues (compared to normal adjacent tissues) and was notably related to tumor volume, distant metastasis. Overexpressing LIPE-AS1 accelerated CC cell proliferation, migration and EMT, inhibited apoptosis; while LIPE-AS1 knockdown had the opposite effects. The mechanism studies confirmed that LIPE-AS1 sponges miR-195-5p as a competitive endogenous RNA (ceRNA), which targets the 3′-untranslated region (3′-UTR) of MAP3K8. LIPE-AS1 promoted the expression of MAP3K8 and enhanced ERK1/2 phosphorylation, which were reversed by miR-195-5p.Significance: LIPE-AS1 regulates CC progression through the miR-195-5p/MAPK signaling pathway, providing new hope for CC diagnosis and treatment.

scholarly journals Chronic AMPK inactivation slows SHH medulloblastoma progression by inhibiting mTORC1 signaling and depleting tumor stem cell populations

2021 ◽  
Author(s):  
Taylor Dismuke ◽  
Daniel S Malawsky ◽  
Hedi Liu ◽  
Jay Brenman ◽  
Andrey Tikunov ◽  
...  
Keyword(s):  
Stem Cell ◽  
Genetic Model ◽  
Cellular Heterogeneity ◽  
Tumor Stem Cell ◽  
Cell Populations ◽  
Therapeutic Effects ◽  
Conditional Expression ◽  
Mtorc1 Signaling ◽  
Stem Cell Populations

We show that inactivating AMPK in vivo in a genetic model of medulloblastoma depletes tumor stem cell populations and slows tumor progression. Medulloblastoma, the most common malignant pediatric brain tumor, grows as heterogenous communities comprising diverse types of tumor and stromal cells. We have previously shown that different types of cells in medulloblastomas show different sensitivities to specific targeted therapies. To determine if specific populations depend on AMPK, we analyzed mice with AMPK-inactivated medulloblastomas. We engineered mice with brain-wide, conditional deletion of the AMPK catalytic subunits Prkaa1 and Prkaa2 and conditional expression SmoM2, an oncogenic Smo allele that hyperactivates Sonic Hedgehog (SHH) signaling. We compared the medulloblastomas that formed in these mice to tumors that form in AMPK-intact mice with conditional SmoM2 expression. AMPK-inactivated tumors progressed more slowly, allowing longer event-free survival. AMPK inactivation altered the cellular heterogeneity, determined by scRNA-seq, increasing differentiation, decreasing tumor stem cell populations and reducing glio-neuronal multipotency. Mechanistically, AMPK inactivation altered glycolytic gene expression and decreased mTORC1 pathway activation. Hk2-deletion reproduced key aspects of the AMPK-inactivation phenotype, implicating altered glycolysis in the tumor suppressive effect of AMPK inactivation. Our results show that AMPK inactivation impairs tumor growth through mechanisms that disproportionately affect tumor stem cell populations. As stem cells are intrinsically resistant to current cytotoxic therapy that drives recurrence, finding ways to target these populations may prevent treatment failure. Our data suggest that targeted AMPK inactivation may produce therapeutic effects in tumor stem cell populations refractory to other therapeutic approaches.

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