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  • 1.
    Andersson, Ulrika
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Oncology.
    Degerman, Sofie
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Dahlin, Anna M.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Oncology.
    Wibom, Carl
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Oncology.
    Johansson, Gunnar
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Oncology.
    Bondy, Melissa L.
    Melin, Beatrice S.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Oncology.
    The association between longer relative leukocyte telomere length and risk of glioma is independent of the potentially confounding factors allergy, BMI, and smoking2019In: Cancer Causes and Control, ISSN 0957-5243, E-ISSN 1573-7225, Vol. 30, no 2, p. 177-185Article in journal (Refereed)
    Abstract [en]

    Purpose: Previous studies have suggested an association between relative leukocyte telomere length (rLTL) and glioma risk. This association may be influenced by several factors, including allergies, BMI, and smoking. Previous studies have shown that individuals with asthma and allergy have shortened relative telomere length, and decreased risk of glioma. Though, the details and the interplay between rLTL, asthma and allergies, and glioma molecular phenotype is largely unknown. Methods: rLTL was measured by qPCR in a Swedish population-based glioma case–control cohort (421 cases and 671 controls). rLTL was related to glioma risk and health parameters associated with asthma and allergy, as well as molecular events in glioma including IDH1 mutation, 1p/19q co-deletion, and EGFR amplification. Results: Longer rLTL was associated with increased risk of glioma (OR = 1.16; 95% CI 1.02–1.31). Similar to previous reports, there was an inverse association between allergy and glioma risk. Specific, allergy symptoms including watery eyes was most strongly associated with glioma risk. High body mass index (BMI) a year prior diagnosis was significantly protective against glioma in our population. Adjusting for allergy, asthma, BMI, and smoking did not markedly change the association between longer rLTL and glioma risk. rLTL among cases was not associated with IDH1 mutation, 1p/19q co-deletion, or EGFR amplification, after adjusting for age at diagnosis and sex. Conclusions: In this Swedish glioma case–control cohort, we identified that long rLTL increases the risk of glioma, an association not confounded by allergy, BMI, or smoking. This highlights the complex interplay of the immune system, rLTL and cancer risk.

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  • 2. Cha, Shih-Ting
    et al.
    Chen, Pai-Sheng
    Johansson, Gunnar
    1Laboratory of Molecular and Cellular Toxicology, Institute of Toxicology, College of Medicine, National Taiwan University.
    Chu, Chia-Yu
    Wang, Ming-Yang
    Jeng, Yung-Ming
    Yu, Sung-Liang
    Chen, Jin-Shing
    Chang, King-Jen
    Jee, Shiou-Hwa
    Tan, Ching-Ting
    Lin, Ming-Tsan
    Kuo, Min-Liang
    MicroRNA-519c suppresses hypoxia-inducible factor-1alpha expression and tumor angiogenesis.2010In: Cancer Research, ISSN 0008-5472, E-ISSN 1538-7445, Vol. 70, no 7, p. 2675-2685Article in journal (Refereed)
    Abstract [en]

    Hypoxia-inducible factor-1alpha (HIF-1alpha) is widely considered to be one of the key regulators of tumor angiogenesis. The upstream regulation is complex and involves several growth factors, cytokines, and hypoxia. Herein, we have identified miR-519c as a hypoxia-independent regulator of HIF-1alpha, acting through direct binding to the HIF-1alpha 3' untranslated region and leading to reduced tumor angiogenesis. Overexpression of miR-519c resulted in a significant decrease of HIF-1alpha protein levels and reduced the tube formation of human umbilical vein endothelial cells; similarly, antagomir inhibition of miR-519c increased the level of HIF-1alpha protein and enhanced angiogenic activity, suggesting an important role of miR-519c in HIF-1alpha-mediated angiogenesis. Consistent with the overexpression of miR-519c in cancer patients with better prognosis, mice injected with miR-519c-overexpressing cells exhibited dramatically reduced HIF-1alpha levels, followed by suppressed tumor angiogenesis, growth, and metastasis. In addition, we found that hepatocyte growth factor (HGF), a known HIF-1alpha inducer, reduced the miR-519c levels through an Akt-dependent pathway. This regulation was posttranscriptional and may be mediated by suppression of miR-519c maturation. Taken together, our findings provide the first evidence that miR-519c is a pivotal regulator of tumor angiogenesis and that microenvironmental HGF contributes to regulating miR-519c biogenesis in cancer cells.

  • 3. Chen, Chi-Kuan
    et al.
    Yang, Ching-Yao
    Hua, Kuo-Tai
    Hua, Kuo-Ti
    Ho, Ming-Chih
    Johansson, Gunnar
    Department of Neurology, National Taiwan University Hospital, and National Taiwan University College of Medicine, Taipei, Taiwan.
    Jeng, Yung-Ming
    Chen, Chiung-Nien
    Chen, Min-Wei
    Lee, Wei-Jiunn
    Su, Jen-Liang
    Lai, Tsung-Ching
    Chou, Chi-Chi
    Ho, Bing-Ching
    Chang, Chuan-Fa
    Lee, Po-Huang
    Chang, King-Jen
    Hsiao, Michael
    Lin, Ming-Tsan
    Kuo, Min-Liang
    Leukocyte cell-derived chemotaxin 2 antagonizes MET receptor activation to suppress hepatocellular carcinoma vascular invasion by protein tyrosine phosphatase 1B recruitment2014In: Hepatology, ISSN 0270-9139, E-ISSN 1527-3350, Vol. 59, no 3, p. 974-985Article in journal (Refereed)
    Abstract [en]

    UNLABELLED: Leukocyte cell-derived chemotoxin 2 (LECT2) has been shown to act as a tumor suppressor in hepatocellular carcinoma (HCC). However, the underlying mechanism has not yet been completely defined. Here, we employ a LECT2-affinity column plus liquid chromatography coupled with tandem mass spectrometry to identify LECT2-binding proteins and found that MET receptor strongly interacted with LECT2 protein. Despite the presence of hepatocyte growth factor, the LECT2 binding causes an antagonistic effect to MET receptor activation through recruitment of protein tyrosine phosphatase 1B. The antagonistic effect of LECT2 on MET activation also mainly contributes to the blockage of vascular invasion and metastasis of HCC. Furthermore, serial deletions and mutations of LECT2 showed that the HxGxD motif is primarily responsible for MET receptor binding and its antagonistic effects.

    CONCLUSION: These findings reveal a novel, specific inhibitory function of LECT2 in HCC by the direct binding and inactivation of MET, opening a potential avenue for treating MET-related liver cancer.

  • 4. Chen, Min-Wei
    et al.
    Hua, Kuo-Tai
    Kao, Hsin-Jung
    Chi, Chia-Chun
    Wei, Lin-Hung
    Johansson, Gunnar
    Graduate Institute of Toxicology, National Taiwan University College of Medicine.
    Shiah, Shine-Gwo
    Chen, Pai-Sheng
    Jeng, Yung-Ming
    Cheng, Tsu-Yao
    Lai, Tsung-Ching
    Chang, Jeng-Shou
    Jan, Yi-Hua
    Chien, Ming-Hsien
    Yang, Chih-Jen
    Huang, Ming-Shyan
    Hsiao, Michael
    Kuo, Min-Liang
    H3K9 histone methyltransferase G9a promotes lung cancer invasion and metastasis by silencing the cell adhesion molecule Ep-CAM2010In: Cancer Research, ISSN 0008-5472, E-ISSN 1538-7445, Vol. 70, no 20, p. 7830-7840Article in journal (Refereed)
    Abstract [en]

    G9a is a mammalian histone methyltransferase that contributes to the epigenetic silencing of tumor suppressor genes. Emerging evidence suggests that G9a is required to maintain the malignant phenotype, but the role of G9a function in mediating tumor metastasis has not been explored. Here, we show that G9a is expressed in aggressive lung cancer cells, and its elevated expression correlates with poor prognosis. RNAi-mediated knockdown of G9a in highly invasive lung cancer cells inhibited cell migration and invasion in vitro and metastasis in vivo. Conversely, ectopic G9a expression in weakly invasive lung cancer cells increased motility and metastasis. Mechanistic investigations suggested that repression of the cell adhesion molecule Ep-CAM mediated the effects of G9a. First, RNAi-mediated knockdown of Ep-CAM partially relieved metastasis suppression imposed by G9a suppression. Second, an inverse correlation between G9a and Ep-CAM expression existed in primary lung cancer. Third, Ep-CAM repression was associated with promoter methylation and an enrichment for dimethylated histone H3K9. G9a knockdown reduced the levels of H3K9 dimethylation and decreased the recruitment of the transcriptional cofactors HP1, DNMT1, and HDAC1 to the Ep-CAM promoter. Our findings establish a functional contribution of G9a overexpression with concomitant dysregulation of epigenetic pathways in lung cancer progression.

  • 5. Chien, Ming-Hsien
    et al.
    Ku, Chia-Chi
    Johansson, Gunnar
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Oncology. Umeå University.
    Chen, Min-Wei
    Hsiao, Michael
    Su, Jen-Liang
    Inoue, Hiroyasu
    Hua, Kuo-Tai
    Wei, Lin-Hung
    Kuo, Min-Liang
    Vascular endothelial growth factor-C (VEGF-C) promotes angiogenesis by induction of COX-2 in leukemic cells via the VEGF-R3/JNK/AP-1 pathway.2009In: Carcinogenesis, ISSN 0143-3334, E-ISSN 1460-2180, Vol. 30, no 12, p. 2005-13Article in journal (Refereed)
    Abstract [en]

    Vascular endothelial growth factor (VEGF)-C is recognized as a tumor lymphangiogenic factor based on the effects of activated VEGF-R3 on lymphatic endothelial cells. Many tumor cells express VEGF-R3 but the function of this receptor in tumor cells is largely unknown. It has been reported that the VEGF-C/VEGF-R3 axis is activated in subsets of leukemia patients. Herein, we have shown that VEGF-C induces angiogenic activity in the tube formation assay invitro and Matrigel plug assay in vivo by upregulating an angiogenic factor, cyclooxygenase-2 (COX-2), through VEGF-R3 in the human acute myeloid leukemia (AML) cell line, THP-1. COX-2 induction by VEGF-C was also observed in other VEGF-R3(+) human AML cell lines (U937 and HL60). Moreover, immunohistochemical analysis of bone marrow specimens of 37 patients diagnosed with AML revealed that VEGF-C expression in specimens was associated with the expression of COX-2 (P < 0.001). The manner by which signaling pathways transduced by VEGF-C is responsible for COX-2 upregulation was further investigated. Blocking the p42/44 mitogen-activated protein kinase (MAPK) pathway with the MAPK kinase inhibitor, PD 98059, failed to inhibit VEGF-C-mediated COX-2 expression. However, VEGF-C-induced COX-2 upregulation was effectively abolished by overexpression of dominant-negative c-Jun N-terminal kinase (JNK) or treatment with the JNK inhibitor, SP 600125. VEGF-C induced JNK-dependent nuclear translocation of c-Jun. Furthermore, chromatin immunoprecipitation and reporter assays revealed that VEGF-C enhanced c-Jun binding to the cyclic adenosine 3',5'-monophosphate-response element of the COX-2 promoter and induced COX-2 expression. In sum, the data herein highlight the pathogenic role of VEGF-C in leukemia via regulation of angiogenesis through upregulation of COX-2.

  • 6. Hua, Kuo-Tai
    et al.
    Tan, Ching-Ting
    Johansson, Gunnar
    Graduate Institute of Toxicology, National Taiwan University College of Medicine, Taipei 100, Taiwan.
    Lee, Jang-Ming
    Yang, Pei-Wen
    Lu, Hsin-Yi
    Chen, Chi-Kuan
    Su, Jen-Liang
    Chen, Poshen B
    Wu, Yu-Ling
    Chi, Chia-Chun
    Kao, Hsin-Jung
    Shih, Hou-Jung
    Chen, Min-Wei
    Chien, Ming-Hsien
    Chen, Pai-Sheng
    Lee, Wei-Jiunn
    Cheng, Tsu-Yao
    Rosenberger, George
    Chai, Chee-Yin
    Yang, Chih-Jen
    Huang, Ming-Shyan
    Lai, Tsung-Ching
    Chou, Teh-Ying
    Hsiao, Michael
    Kuo, Min-Liang
    N-α-acetyltransferase 10 protein suppresses cancer cell metastasis by binding PIX proteins and inhibiting Cdc42/Rac1 activity2011In: Cancer Cell, ISSN 1535-6108, E-ISSN 1878-3686, Vol. 19, no 2, p. 218-231Article in journal (Refereed)
    Abstract [en]

    N-α-acetyltransferase 10 protein, Naa10p, is an N-acetyltransferase known to be involved in cell cycle control. We found that Naa10p was expressed lower in varieties of malignancies with lymph node metastasis compared with non-lymph node metastasis. Higher Naa10p expression correlates the survival of lung cancer patients. Naa10p significantly suppressed migration, tumor growth, and metastasis independent of its enzymatic activity. Instead, Naa10p binds to the GIT-binding domain of PIX, thereby preventing the formation of the GIT-PIX-Paxillin complex, resulting in reduced intrinsic Cdc42/Rac1 activity and decreased cell migration. Forced expression of PIX in Naa10-transfected tumor cells restored the migration and metastasis ability. We suggest that Naa10p functions as a tumor metastasis suppressor by disrupting the migratory complex, PIX-GIT- Paxillin, in cancer cells.

  • 7.
    Johansson, Gunnar
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Oncology.
    Andersson, Ulrika
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Oncology.
    Melin, Beatrice
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Oncology.
    Recent developments in brain tumor predisposing syndromes2016In: Acta Oncologica, ISSN 0284-186X, E-ISSN 1651-226X, Vol. 55, no 4, p. 401-411Article, review/survey (Refereed)
    Abstract [en]

    The etiologies of brain tumors are in the most cases unknown, but improvements in genetics and DNA screening have helped to identify a wide range of brain tumor predisposition disorders. In this review we are discussing some of the most common predisposition disorders, namely: neurofibromatosis type 1 and 2, schwannomatosis, rhabdoid tumor predisposition disorder, nevoid basal cell carcinoma syndrome (Gorlin), tuberous sclerosis complex, von Hippel-Lindau, Li-Fraumeni and Turcot syndromes. Recent findings from the GLIOGENE collaboration and the newly identified glioma causing gene POT1, will also be discussed. Genetics. We will describe these disorders from a genetic and clinical standpoint, focusing on the difference in clinical symptoms depending on the underlying gene or germline mutation. Central nervous system (CNS) tumors. Most of these disorders predispose the carriers to a wide range of symptoms. Herein, we will focus particularly on tumors affecting the CNS and discuss improvements of targeted therapy for the particular disorders.

  • 8.
    Johansson, Gunnar
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Oncology.
    Brännström, Thomas
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Andersson, Ulrika
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Oncology.
    Golovleva, Irina
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Medical and Clinical Genetics.
    Melin, Beatrice
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Oncology.
    Molecular classification of malignat glioma2017In: Neuro-Oncology, ISSN 1522-8517, E-ISSN 1523-5866, Vol. 19, no S3, p. 88-88, article id P10.15Article in journal (Refereed)
    Abstract [en]

    Background: Malignant glioma are devastating tumors with poor prognosis. In recent years, the classification of glioma have evolved greatly due to exploration of several molecular tools in addition to the traditional immunohistochemistry.

    Methods: To further evolve this classification, we thoroughly characterized the molecular and histological signature of 367 glioma patients from Sweden. We first obtained the full medical history and histological classification, along with matched blood samples and unstained tissue slides. We have performed extensive molecular characterization using genome wide association studies, methylation arrays and telomere length assays. We have extended the classification to include IDH1 mutations, chromosome 1p/19q co-deletion, EGFR amplification as well as the expression of two novel cell signaling regulators. The statistical analysis is ongoing and will reveal how well we can classify the tumors by combining the above mentioned techniques. 

    Results: As expected we found EGFR upregulation in almost 50% of the patients with glioblastoma and one third of patients with anaplastic astrocytoma and anaplastic oligodendroglioma. No EGFR expression was found in any patient with low grade glioma. In consistence with previous studies 70% of the IDH1 mutated oligodendroglioma had 1p/19q co-deletion. In the IDH1 wildtype oligodendroglioma, about 50% of the low grade tumors had 1p/19q co-deletion. Interestingly, we found complete 1p/19q co-deletion in about 10% of the IDH1 wild type glioblastoma.

    Conclusion: Today, 1p/19q co-deletion is normally only studied in suspected oligodendroglioma and not in all types of glioma. Pending the clinical relevance of the 1p/19q co-deleted glioblastoma, it might be wise to expand the 1p/19q classification by including all types of glioma.

  • 9.
    Johansson, Gunnar
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Oncology. Umeå University.
    Mahller, Yonatan Y
    Collins, Margaret H
    Kim, Mi-Ok
    Nobukuni, Takahiro
    Perentesis, John
    Cripe, Timothy P
    Lane, Heidi A
    Kozma, Sara C
    Thomas, George
    Ratner, Nancy
    Effective in vivo targeting of the mammalian target of rapamycin pathway in malignant peripheral nerve sheath tumors.2008In: Molecular Cancer Therapeutics, ISSN 1535-7163, E-ISSN 1538-8514, Vol. 7, no 5, p. 1237-45Article in journal (Refereed)
    Abstract [en]

    Malignant peripheral nerve sheath tumors (MPNST) are chemoresistant sarcomas with poor 5-year survival that arise in patients with neurofibromatosis type 1 (NF1) or sporadically. We tested three drugs for single and combinatorial effects on collected MPNST cell lines and in MPNST xenografts. The mammalian target of rapamycin complex 1 inhibitor RAD001 (Everolimus) decreased growth 19% to 60% after 4 days of treatment in NF1 and sporadic-derived MPNST cell lines. Treatment of subcutaneous sporadic MPNST cell xenografts with RAD001 significantly, but transiently, delayed tumor growth, and decreased vessel permeability within xenografts. RAD001 combined with the epidermal growth factor receptor tyrosine kinase inhibitor erlotinib caused additional inhibitory effects on growth and apoptosis in vitro, and a small but significant additional inhibitory effect on MPNST growth in vivo that were larger than the effects of RAD001 with doxorubicin. RAD001 plus erlotinib, in vitro and in vivo, reduced phosphorylation of AKT and total AKT levels, possibly accounting for their additive effect. The results support the consideration of RAD001 therapy in NF1 patient and sporadic MPNST. The preclinical tests described allow rapid screening strata for drugs that block MPNST growth, prior to tests in more complex models, and should be useful to identify drugs that synergize with RAD001.

  • 10.
    Johansson, Gunnar
    et al.
    Department of Neurology, National Taiwan University Hospital, Taipei, Taiwan .
    Peng, Po-Chun
    Huang, Po-Yuan
    Chien, Hsiung-Fei
    Hua, Kuo-Tai
    Kuo, Min-Liang
    Chen, Chin-Tin
    Lee, Ming-Jen
    Soluble AXL: a possible circulating biomarker for neurofibromatosis type 1 related tumor burden2014In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, no 12, article id e115916Article in journal (Refereed)
    Abstract [en]

    Neurofibromatosis type 1 (NF1) is the most common tumor predisposition disorder affecting 1/3500 worldwide. Patients are at risk of developing benign (neurofibromas) and malignant peripheral nerve sheath tumors (MPNST). The AXL receptor tyrosine kinase has been implicated in several kinds of cancers, but so far no studies have investigated the role of AXL in NF1 related tumorigenesis. Recently, the soluble fraction from the extracellular domain of AXL (sAXL) has been found in human plasma, and its level was correlated to poor prognosis in patients with renal cancer. Compared to normal human Schwann cells, a significantly high expression level of AXL was found in three of the four MPNST cell lines and two of the three primary MPNST tissues. Similarly, the level of sAXL in conditioned media corresponded to the protein and mRNA levels of AXL in the MPNST cell lines. Furthermore, in two different human MPNST xenograft models, the human sAXL could be detected in the mouse plasma. Its level was proportionate to the size of the xenograft tumors, while no human sAXL was detect prior to the formation of the tumors. Treatment with a newly developed photodynamic therapy, prevented further tumor growth and resulted in drastically reduced the levels of sAXL compared to that of the control group. Finally, the level of sAXL was significantly increased in patients with plexiform tumors compared to patients with only dermal neurofibromas, further supporting the role of sAXL as a marker for NF1 related tumor burden.

  • 11. Miller, Shyra J
    et al.
    Li, Hongzhen
    Rizvi, Tilat A
    Huang, Yuan
    Johansson, Gunnar
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Oncology. Umeå University.
    Bowersock, Jason
    Sidani, Amer
    Vitullo, John
    Vogel, Kristine
    Parysek, Linda M
    DeClue, Jeffrey E
    Ratner, Nancy
    Brain lipid binding protein in axon-Schwann cell interactions and peripheral nerve tumorigenesis.2003In: Molecular and Cellular Biology, ISSN 0270-7306, E-ISSN 1098-5549, Vol. 23, no 6, p. 2213-24Article in journal (Refereed)
    Abstract [en]

    Loss of axonal contact characterizes Schwann cells in benign and malignant peripheral nerve sheath tumors (MPNST) from neurofibromatosis type 1 (NF1) patients. Tumor Schwann cells demonstrate NF1 mutations, elevated Ras activity, and aberrant epidermal growth factor receptor (EGFR) expression. Using cDNA microarrays, we found that brain lipid binding protein (BLBP) is elevated in an EGFR-positive subpopulation of Nf1 mutant mouse Schwann cells (Nf1(-/-) TXF) that grows away from axons; BLBP expression was not affected by farnesyltransferase inhibitor, an inhibitor of H-Ras. BLBP was also detected in EGFR-positive cell lines derived from Nf1:p53 double mutant mice and human MPNST. BLBP expression was induced in normal Schwann cells following transfection with EGFR but not H-Ras12V. Furthermore, EGFR-mediated BLBP expression was not inhibited by dominant-negative H-Ras, indicating that BLBP expression is downstream of Ras-independent EGFR signaling. BLBP-blocking antibodies enabled process outgrowth from Nf1(-/-) TXF cells and restored interaction with axons, without affecting cell proliferation or migration. Following injury, BLBP expression was induced in normal sciatic nerves when nonmyelinating Schwann cells remodeled their processes. These data suggest that BLBP, stimulated by Ras-independent pathways, regulates Schwann cell-axon interactions in normal peripheral nerve and peripheral nerve tumors.

  • 12. Patel, Ami V
    et al.
    Johansson, Gunnar
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Oncology.
    Colbert, Melissa C
    Dasgupta, Biplab
    Ratner, Nancy
    Fatty acid synthase is a metabolic oncogene targetable in malignant peripheral nerve sheath tumors2015In: Neuro-Oncology, ISSN 1522-8517, E-ISSN 1523-5866, Vol. 17, no 12, p. 1599-1608Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Malignant peripheral nerve sheath tumors (MPNSTs) are soft tissue sarcomas with minimal therapeutic opportunities. We observed that lipid droplets (LDs) accumulate in human MPNST cell lines and in primary human tumor samples. The goal of this study was to investigate the relevance of lipid metabolism to MPNST survival and as a possible therapeutic target.

    METHODS: Based on preliminary findings that MPNSTs accumulate LDs, we hypothesized that a deregulated lipid metabolism supports MPNST cell survival/proliferation rate. To test this, we examined respiration, role of fatty acid oxidation (FAO), and the enzyme fatty acid synthase involved in de novo fatty acid synthesis in MPNSTs using both genetic and pharmacological tools.

    RESULTS: We demonstrate that LDs accumulate in MPNST cell lines, primary human and mouse MPNST tumors, and neural crest cells. LDs from MPNST cells disappear on lipid deprivation, indicating that LDs can be oxidized as a source of energy. Inhibition of FAO decreased oxygen consumption and reduced MPNST survival, indicating that MPNST cells likely metabolize LDs through active FAO. FAO inhibition reduced oxygen consumption and survival even in the absence of exogenous lipids, indicating that lipids synthesized de novo can also be oxidized. Consequently, inhibition of de novo fatty acid synthesis, which is overexpressed in human MPNST cell lines, effectively reduced MPNST survival and delayed induction of tumor growth in vivo.

    CONCLUSION: Our results show that MPNSTs depend on lipid metabolic pathways and suggest that disrupting lipid metabolism could be a potential new strategy for the development of MPNST therapeutics.

  • 13. Su, Jen-Liang
    et al.
    Chen, Pai-Sheng
    Johansson, Gunnar
    Institute of Toxicology, National Taiwan University, No. 1, Section 1, Jen-Ai Road, Taipei, 100, Taiwan.
    Kuo, Min-Liang
    Function and regulation of let-7 family microRNAs2012In: MicroRNA (Shāriqah, United Arab Emirates), ISSN 2211-5366, Vol. 1, no 1, p. 34-39Article in journal (Refereed)
    Abstract [en]

    MicroRNAs (miRNAs) are a group of small noncoding RNAs capable of regulating specific gene expression. Let-7 miRNA was first discovered in Caenorhabditis elegans and it is highly conserved in human tissues. The human let- 7 family of miRNA contains 12 members of miRNA. Today, these members have become the most studied miRNAs and they have attracted attention of researchers in various fields, such as development, stem cell biology, aging, and metabolism. Furthermore, there is a large body of evidence linking the loss of let-7 expression and the development of poorly differentiated, aggressive cancers. In addition to the canonical biogenesis pathway, let-7 has been found to be regulated by protein factors, such as RNA binding proteins previously identified as regulators of protein-coding mRNAs. Moreover, the direct interaction between miRNAs has recently been identified as a novel pathway to control let-7 expression. In this review, we discuss the multifaceted roles of let-7 and provide an overview of its regulation at multiple levels.

  • 14. Williams, Jon P
    et al.
    Wu, Jianqiang
    Johansson, Gunnar
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Oncology. Umeå University.
    Rizvi, Tilat A
    Miller, Shyra C
    Geiger, Hartmut
    Malik, Punam
    Li, Wenling
    Mukouyama, Yoh-suke
    Cancelas, Jose A
    Ratner, Nancy
    Nf1 mutation expands an EGFR-dependent peripheral nerve progenitor that confers neurofibroma tumorigenic potential.2008In: Cell stem cell, ISSN 1875-9777, Vol. 3, no 6, p. 658-69Article in journal (Refereed)
    Abstract [en]

    Defining growth factor requirements for progenitors facilitates their characterization and amplification. We characterize a peripheral nervous system embryonic dorsal root ganglion progenitor population using in vitro clonal sphere-formation assays. Cells differentiate into glial cells, smooth muscle/fibroblast (SM/Fb)-like cells, and neurons. Genetic and pharmacologic tools revealed that sphere formation requires signaling from the EGFR tyrosine kinase. Nf1 loss of function amplifies this progenitor pool, which becomes hypersensitive to growth factors and confers tumorigenesis. DhhCre;Nf1(fl/fl) mouse neurofibromas contain a progenitor population with similar growth requirements, potential, and marker expression. In humans, NF1 mutation predisposes to benign neurofibromas, incurable peripheral nerve tumors. Prospective identification of human EGFR(+);P75(+) neurofibroma cells enriched EGF-dependent sphere-forming cells. Neurofibroma spheres contain glial-like progenitors that differentiate into neurons and SM/Fb-like cells in vitro and form benign neurofibroma-like lesions in nude mice. We suggest that expansion of an EGFR-expressing early glial progenitor contributes to neurofibroma formation.

  • 15. Wood, Matthew
    et al.
    Rawe, Melissa
    Johansson, Gunnar
    Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital, University of Cincinnati College of Medicine.
    Pang, Shu
    Soderquist, Ryan S
    Patel, Ami V
    Nelson, Sandra
    Seibel, William
    Ratner, Nancy
    Sanchez, Yolanda
    Discovery of a small molecule targeting IRA2 deletion in budding yeast and neurofibromin loss in malignant peripheral nerve sheath tumor cells2011In: Molecular Cancer Therapeutics, ISSN 1535-7163, E-ISSN 1538-8514, Vol. 10, no 9, p. 1740-1750Article in journal (Refereed)
    Abstract [en]

    Malignant peripheral nerve sheath tumor (MPNST) is a life-threatening complication of neurofibromatosis type 1 (NF1). NF1 is caused by mutation in the gene encoding neurofibromin, a negative regulator of Ras signaling. There are no effective pharmacologic therapies for MPNST. To identify new therapeutic approaches targeting this dangerous malignancy, we developed assays in NF1(+/+) and NF1(-/-) MPNST cell lines and in budding yeast lacking the NF1 homologue IRA2 (ira2Δ). Here, we describe UC1, a small molecule that targets NF1(-/-) cell lines and ira2Δ budding yeast. By using yeast genetics, we identified NAB3 as a high-copy suppressor of UC1 sensitivity. NAB3 encodes an RNA binding protein that associates with the C-terminal domain of RNA Pol II and plays a role in the termination of nonpolyadenylated RNA transcripts. Strains with deletion of IRA2 are sensitive to genetic inactivation of NAB3, suggesting an interaction between Ras signaling and Nab3-dependent transcript termination. This work identifies a lead compound and a possible target pathway for NF1-associated MPNST, and shows a novel model system approach to identify and validate target pathways for cancer cells in which NF1 loss drives tumor formation.

  • 16.
    Wu, Wendy Yi-Ying
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Oncology.
    Johansson, Gunnar
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Oncology.
    Wibom, Carl
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Oncology.
    Brännström, Thomas
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Malmström, Annika
    Henriksson, Roger
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Oncology.
    Golovleva, Irina
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Medical and Clinical Genetics.
    Bondy, Melissa L.
    Andersson, Ulrika
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Oncology.
    Dahlin, Anna M.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Oncology.
    Melin, Beatrice S.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Oncology.
    The Genetic Architecture of Gliomagenesis-Genetic Risk Variants Linked to Specific Molecular Subtypes2019In: Cancers, ISSN 2072-6694, Vol. 11, no 12, article id 2001Article, review/survey (Refereed)
    Abstract [en]

    Genome-wide association studies have identified 25 germline genetic loci that increase the risk of glioma. The somatic tumor molecular alterations, including IDH-mutation status and 1p/19q co-deletion, have been included into the WHO 2016 classification system for glioma. To investigate how the germline genetic risk variants correlate with the somatic molecular subtypes put forward by WHO, we performed a meta-analysis that combined findings from 330 Swedish cases and 876 controls with two other recent studies. In total, 5,103 cases and 10,915 controls were included. Three categories of associations were found. First, variants in TERT and TP53 were associated with increased risk of all glioma subtypes. Second, variants in CDKN2B-AS1, EGFR, and RTEL1 were associated with IDH-wildtype glioma. Third, variants in CCDC26 (the 8q24 locus), C2orf80 (close to IDH), LRIG1, PHLDB1, ETFA, MAML2 and ZBTB16 were associated with IDH-mutant glioma. We therefore propose three etiopathological pathways in gliomagenesis based on germline variants for future guidance of diagnosis and potential functional targets for therapies. Future prospective clinical trials of patients with suspicion of glioma diagnoses, using the genetic variants as biomarkers, are necessary to disentangle how strongly they can predict glioma diagnosis.

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