| 1. |
- Baryawno, Ninib, et al.
(författare)
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Detection of human cytomegalovirus in medulloblastomas reveals a potential therapeutic target
- 2011
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Ingår i: Journal of Clinical Investigation. - 0021-9738 .- 1558-8238. ; 121:10, s. 4043-4055
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Tidskriftsartikel (refereegranskat)abstract
- Medulloblastomas are the most common malignant brain tumors in children. They express high levels of COX-2 and produce PGE(2), which stimulates tumor cell proliferation. Human cytomegalovirus (HCMV) is prevalent in the human population and encodes proteins that provide immune evasion strategies and promote oncogenic transformation and oncomodulation. In particular, HCMV induces COX-2 expression; STAT3 phosphorylation; production of PGE2, vascular endothelial growth factor, and IL-6; and tumor formation in vivo. Here, we show that a large proportion of primary medulloblastomas and medulloblastoma cell lines are infected with HCMV and that COX-2 expression, along with PGE2 levels, in tumors is directly modulated by the virus. Our analysis indicated that both HCMV immediate-early proteins and late proteins are expressed in the majority of primary medulloblastomas. Remarkably, all of the human medulloblastoma cell lines that we analyzed contained HCMV DNA and RNA and expressed HCMV proteins at various levels in vitro. When engrafted into immunocompromised mice, human medulloblastoma cells induced expression of HCMV proteins. HCMV and COX-2 expression correlated in primary tumors, cell lines, and medulloblastoma xenografts. The antiviral drug valganciclovir and the specific COX-2 inhibitor celecoxib prevented HCMV replication in vitro and inhibited PGE2 production and reduced medulloblastoma tumor cell growth both in vitro and in vivo. Ganciclovir did riot affect the growth of HCMV-negative tumor cell lines. These findings imply an important role for HCMV in medulloblastoma and suggest HCMV as a novel therapeutic target for this tumor.
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| 2. |
- Baryawno, Ninib
(författare)
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New potential targets in medulloblastoma therapy : studies on cellular mechanisms and mediators
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Medulloblastoma is an embryonal tumour that mainly affects children. It is the most common malignant brain tumour in children and accounts for 15% of all childhood brain tumours. It most often presents in the cerebellum and is considered to be a disorder of normal development. Despite intensive multimodal therapy, survival in high-risk patients is still poor, and long-time survivors suffer from detrimental side effects. To improve outcome, new treatments based on a better understanding of medulloblastoma biology are needed. Prostaglandin E2 (PGE2) is a proinflammatory eicosanoid that is linked to cancer progression and development. It is formed from arachidonic acid through enzymatic conversion catalyzed by cyclooxygenases (COX-1/2). PGE2 promotes tumour growth by activating signalling pathways that control cell proliferation, invasion, apoptosis, angiogenesis and immunosuppression. We found that COX-2/PGE2 signalling is activated in medulloblastoma, and that PGE2 has an important role in medulloblastoma growth. Celecoxib, a selective COX-2 inhibitor, demonstrated promising effects against medulloblastoma tumour growth both alone and when combined with cytostatic drugs. Celecoxib potentiated the effect of the DNA alkylator temozolomide by downregulating MGMT expression and by inhibiting proliferation of CD15/CD133 positive medulloblastoma cells. Canonical Wnt signalling pathway and phosphoinositide-3-kinase (PI3K)/Akt pathway are crucial for normal cerebellar development. In medulloblastoma, activation of Wnt/beta-catenin and PI3K/Akt signalling are commonly observed. Our results show that PI3K/Akt-Wnt/beta-catenin cross-talk is important for medulloblastoma tumourigenesis. We demonstrated that OSU03012, a small molecule inhibitor of the PI3K/Akt signalling protein phosphoinositide-dependent protein kinase-1, suppresses medulloblastoma growth both in vitro and in vivo by interfering with GSK-3beta inactivation and beta-catenin activity. Furthermore, OSU03012 induced synergistic cytotoxicity when combined with chemotherapeutic drugs and augmented the antitumour effect of the mammalian target of rapamycin inhibitor CCI-779 in vivo. Human cytomegalovirus (HCMV) is an oncomodulatory virus that has recently been detected in tumours of different origin. We found a high prevalence of HCMV in medulloblastoma primary tumours and cell lines and showed that infection with HCMV upregulates production of PGE2 in medulloblastoma. Treatment with the antiviral drugs ganciclovir/valganciclovir or celecoxib inhibited medulloblastoma tumour growth both in vitro and in vivo, and the combined therapy demonstrated augmented effects. Based on our observations we suggest that HCMV may, indirectly through the activation of COX-2, be an etiological factor in medulloblastoma development. In summary, this thesis has identified PGE2/COX-2, the PI3K/Akt-Wnt/beta-catenin cross-talk and HCMV as novel targets in medulloblastoma. Compounds that inhibit these targets demonstrate promising effects in experimental models of medulloblastomas, supporting the rationale for clinical testing as novel adjuvant therapy for children with medulloblastoma.
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| 3. |
- Baryawno, Ninib, et al.
(författare)
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Tumor-growth-promoting cyclooxygenase-2 prostaglandin E2 pathway provides medulloblastoma therapeutic targets
- 2008
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Ingår i: Neuro-Oncology. - : Oxford University Press (OUP). - 1522-8517 .- 1523-5866. ; 10:5, s. 661-674
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Tidskriftsartikel (refereegranskat)abstract
- Prostaglandin E(2) (PGE(2)) has been shown to play important roles in several aspects of tumor development and progression. PGE(2) is synthesized from arachidonic acid by cyclooxygenases (COX) and prostaglandin E synthases (PGES) and mediates its biological activity through binding to the four prostanoid receptors EP(1) through EP(4). In this study, we show for the first time that medulloblastoma (MB), the most common malignant childhood brain tumor, expresses high levels of COX-2, microsomal prostaglandin E synthase-1, and EP(1) through EP(4) and secretes PGE(2). PGE(2) and the EP(2) receptor agonist butaprost stimulated MB cell proliferation. Treatment of MB cells with COX inhibitors suppressed PGE(2) production and induced caspase-dependent apoptosis. Similarly, specific COX-2 silencing by small interfering RNA inhibited MB cell growth. EP(1) and EP(3) receptor antagonists ONO-8713 and ONO-AE3-240, but not the EP(4) antagonists ONO-AE3-208 and AH 23848, inhibited tumor cell proliferation, indicating the significance of EP(1) and EP(3) but not EP(4) for MB growth. Administration of COX inhibitors at clinically achievable nontoxic concentrations significantly inhibited growth of established human MB xenografts. Apoptosis was increased, proliferation was reduced, and angiogenesis was inhibited in MBs treated with COX inhibitors. This study suggests that PGE(2) is important for MB growth and that therapies targeting the prostanoid metabolic pathway are potentially beneficial and should be tested in clinical settings for treatment of children with MB.
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| 4. |
- Milosevic, Jelena, et al.
(författare)
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High Expression of PPM1D Induces Tumors Phenotypically Similar to TP53 Loss-of-Function Mutations in Mice
- 2021
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Ingår i: Cancers. - : MDPI. - 2072-6694. ; 13:21
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Tidskriftsartikel (refereegranskat)abstract
- PPM1D is a negative regulator of p53 and genomic aberrations resulting in increased activity of PPM1D have been observed in cancers of different origins, indicating that PPM1D has oncogenic properties. We established a transgenic mouse model overexpressing PPM1D and showed that these mice developed a wide variety of cancers. PPM1D-expressing mice developed tumors phenotypically and genetically similar to tumors in mice with dysfunctional p53. T-cell lymphoblastic lymphoma was the most frequent cancer observed in these mice (55%) followed by adenocarcinomas (24%), leukemia (12%) and other solid tumors including neuroblastoma. Characterization of T-cell lymphomas in mice overexpressing PPM1D demonstrates Pten-deletion and p53-accumulation similar to mice with p53 loss-of-function. Also, Notch1 mutations which are recurrently observed in T-cell acute lymphoblastic lymphoma (T-ALL) were frequently detected in PPM1D-transgenic mice. Hence, PPM1D acts as an oncogenic driver in connection with cellular stress, suggesting that the PPM1D gene status and expression levels should be investigated in TP53 wild-type tumors.
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| 5. |
- Milosevic, Jelena, et al.
(författare)
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PPM1D is a neuroblastoma oncogene and therapeutic target in childhood neural tumors
- 2020
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Majority of cancers harbor alterations of the tumor suppressor TP53. However, childhood cancers, including unfavorable neuroblastoma, often lack TP53 mutations despite frequent loss of p53 function, suggesting alternative p53 inactivating mechanisms.Here we show that p53-regulating PPM1D at chromosome 17q22.3 is linked to aggressive tumors and poor prognosis in neuroblastoma. We identified that WIP1-phosphatase encoded by PPM1D, is activated by frequent segmental 17q-gain further accumulated during clonal evolution, gene-amplifications, gene-fusions or gain-of-function somatic and germline mutations. Pharmacological and genetic manipulation established WIP1 as a druggable target in neuroblastoma. Genome-scale CRISPR-Cas9 screening demonstrated PPM1D genetic dependency in TP53 wild-type neuroblastoma cell lines, and shRNA PPM1D knockdown significantly delayed in vivo tumor formation. Establishing a transgenic mouse model overexpressing PPM1D showed that these mice develop cancers phenotypically and genetically similar to tumors arising in mice with dysfunctional p53 when subjected to low-dose irradiation. Tumors include T-cell lymphomas harboring Notch1-mutations, Pten-deletions and p53-accumulation, adenocarcinomas and PHOX2B-expressing neuroblastomas establishing PPM1D as a bona fide oncogene in wtTP53 cancer and childhood neuroblastoma. Pharmacological inhibition of WIP1 suppressed the growth of neural tumors in nude mice proposing WIP1 as a therapeutic target in neural childhood tumors.
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| 6. |
- Olsen, Thale Kristin, et al.
(författare)
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DHODH is an independent prognostic marker and potent therapeutic target in neuroblastoma
- 2022
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Ingår i: JCI Insight. - : AMER SOC CLINICAL INVESTIGATION INC. - 2379-3708. ; 7:17
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Tidskriftsartikel (refereegranskat)abstract
- Despite intensive therapy, children with high-risk neuroblastoma are at risk of treatment failure. We applied a multiomic system approach to evaluate metabolic vulnerabilities in human neuroblastoma. We combined metabolomics, CRISPR screening, and transcriptomic data across more than 700 solid tumor cell lines and identified dihydroorotate dehydrogenase (DHODH), a critical enzyme in pyrimidine synthesis, as a potential treatment target. Of note, DHODH inhibition is currently under clinical investigation in patients with hematologic malignancies. In neuroblastoma, DHODH expression was identified as an independent risk factor for aggressive disease, and high DHODH levels correlated to worse overall and event-free survival. A subset of tumors with the highest DHODH expression was associated with a dismal prognosis, with a 5-year survival of less than 10%. In xenograft and transgenic neuroblastoma mouse models treated with the DHODH inhibitor brequinar, tumor growth was dramatically reduced, and survival was extended. Furthermore, brequinar treatment was shown to reduce the expression of MYC targets in 3 neuroblastoma models in vivo. A combination of brequinar and temozolomide was curative in the majority of transgenic TH-MYCN neuroblastoma mice, indicating a highly active clinical combination therapy. Overall, DHODH inhibition combined with temozolomide has therapeutic potential in neuroblastoma, and we propose this combination for clinical testing.
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| 7. |
- Valind, Anders, et al.
(författare)
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Macrophage infiltration promotes regrowth in MYCN-amplified neuroblastoma after chemotherapy
- 2023
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Ingår i: OncoImmunology. - 2162-4011 .- 2162-402X. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Despite aggressive treatment, the 5-year event-free survival rate for children with high-risk neuroblastoma is <50%. While most high-risk neuroblastoma patients initially respond to treatment, often with complete clinical remission, many eventually relapse with therapy-resistant tumors. Novel therapeutic alternatives that prevent the recurrence of therapy-resistant tumors are urgently needed. To understand the adaptation of neuroblastoma under therapy, we analyzed the transcriptomic landscape in 46 clinical tumor samples collected before (PRE) or after (POST) treatment from 22 neuroblastoma patients. RNA sequencing revealed that many of the top-upregulated biological processes in POST MYCN amplified (MNA +) tumors compared to PRE MNA + tumors were immune-related, and there was a significant increase in numerous genes associated with macrophages. The infiltration of macrophages was corroborated by immunohistochemistry and spatial digital protein profiling. Moreover, POST MNA + tumor cells were more immunogenic compared to PRE MNA + tumor cells. To find support for the macrophage-induced outgrowth of certain subpopulations of immunogenic tumor cells following treatment, we examined the genetic landscape in multiple clinical PRE and POST tumor samples from nine neuroblastoma patients revealing a significant correlation between an increased amount of copy number aberrations (CNA) and macrophage infiltration in POST MNA + tumor samples. Using an in vivo neuroblastoma patient-derived xenograft (PDX) chemotherapy model, we further show that inhibition of macrophage recruitment with anti-CSF1R treatment prevents the regrowth of MNA + tumors following chemotherapy. Taken together, our work supports a therapeutic strategy for fighting the relapse of MNA + neuroblastoma by targeting the immune microenvironment.
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| 8. |
- Verhoeven, Bronte Manouk, et al.
(författare)
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The immune cell atlas of human neuroblastoma
- 2022
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Ingår i: Cell Reports Medicine. - : Elsevier BV. - 2666-3791. ; 69
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Tidskriftsartikel (refereegranskat)abstract
- Understanding the complete immune cell composition of human neuroblastoma (NB) is crucial for the development of immunotherapeutics. Here, we perform single-cell RNA sequencing (scRNA-seq) on 19 human NB samples coupled with multiplex immunohistochemistry, survival analysis, and comparison with normal fetal adrenal gland data. We provide a comprehensive immune cell landscape and characterize cell-state changes from normal tissue to NB. Our analysis reveals 27 immune cell subtypes, including distinct subpopulations of myeloid, NK, B, and T cells. Several different cell types demonstrate a survival benefit. In contrast to adult cancers and previous NB studies, we show an increase in inflammatory monocyte cell state when contrasting normal and tumor tissue, while no differences in cytotoxicity and exhaustion score for T cells, nor in Treg activity, are observed. Our receptor-ligand interaction analysis reveals a highly complex interactive network of the NB microenvironment from which we highlight several interactions that we suggest for future therapeutic studies.
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| 9. |
- Wickstrom, Malin, et al.
(författare)
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Targeting the hedgehog signal transduction pathway at the level of GLI inhibits neuroblastoma cell growth in vitro and in vivo
- 2013
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Ingår i: International Journal of Cancer. - : Wiley. - 0020-7136 .- 1097-0215. ; 132:7, s. 1516-1524
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Tidskriftsartikel (refereegranskat)abstract
- Hedgehog (HH) signaling is an important regulator of embryogenesis that has been associated with the development of several types of cancer. HH signaling is characterized by Smoothened (SMO)-dependent activation of the GLI transcription factors, which regulate the expression of critical developmental genes. Neuroblastoma, an embryonal tumor of the sympathetic nervous system, was recently shown to express high levels of key molecules in this signaling cascade. Using compounds blocking SMO (cyclopamine and SANT1) or GLI1/GLI2 (GANT61) activity revealed that inhibition of HH signaling at the level of GLI was most effective in reducing neuroblastoma growth. GANT61 sensitivity positively correlated to GLI1 and negatively to MYCN expression in the neuroblastoma cell lines tested. GANT61 downregulated GLI1, c-MYC, MYCN and Cyclin D1 expression and induced apoptosis of neuroblastoma cells. The effects produced by GANT61 were mimicked by GLI knockdown but not by SMO knockdown. Furthermore, GANT61 enhanced the effects of chemotherapeutic drugs used in the treatment of neuroblastoma in an additive or synergistic manner and reduced the growth of established neuroblastoma xenografts in nude mice. Taken together this study suggests that inhibition of HH signaling is a highly relevant therapeutic target for high-risk neuroblastoma lacking MYCN amplification and should be considered for clinical testing.
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| 10. |
- Wickström, Malin, et al.
(författare)
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Wnt/β-catenin pathway regulates MGMT gene expression in cancer and inhibition of Wnt signalling prevents chemoresistance.
- 2015
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- The DNA repair enzyme O6-methylguanine-DNA methyltransferase (MGMT) is commonly overexpressed in cancers and is implicated in the development of chemoresistance. The use of drugs inhibiting MGMT has been hindered by their haematologic toxicity and inefficiency. As a different strategy to inhibit MGMT we investigated cellular regulators of MGMT expression in multiple cancers. Here we show a significant correlation between Wnt signalling and MGMT expression in cancers with different origin and confirm the findings by bioinformatic analysis and immunofluorescence. We demonstrate Wnt-dependent MGMT gene expression and cellular co-localization between active β-catenin and MGMT. Pharmacological or genetic inhibition of Wnt activity downregulates MGMT expression and restores chemosensitivity of DNA-alkylating drugs in mouse models. These findings have potential therapeutic implications for chemoresistant cancers, especially of brain tumours where the use of temozolomide is frequently used in treatment.
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