Hypoxia Inducible Factor 1α Inhibits the Expression of Immunosuppressive Tryptophan-2,3-Dioxygenase in Glioblastoma
Abnormal circulation in solid tumors results in hypoxia, which modulates both tumor intrinsic malignant properties as well as anti-tumor immune responses. Given the importance of hypoxia in glioblastoma (GBM) biology and particularly in shaping anti-tumor immunity, we analyzed which immunomodulatory...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2019-12-01
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| Series: | Frontiers in Immunology |
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| Online Access: | https://www.frontiersin.org/article/10.3389/fimmu.2019.02762/full |
| _version_ | 1828792175378300928 |
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| author | Soumya R. Mohapatra Ahmed Sadik Ahmed Sadik Lars-Oliver Tykocinski Jørn Dietze Gernot Poschet Ines Heiland Christiane A. Opitz Christiane A. Opitz |
| author_facet | Soumya R. Mohapatra Ahmed Sadik Ahmed Sadik Lars-Oliver Tykocinski Jørn Dietze Gernot Poschet Ines Heiland Christiane A. Opitz Christiane A. Opitz |
| author_sort | Soumya R. Mohapatra |
| collection | DOAJ |
| description | Abnormal circulation in solid tumors results in hypoxia, which modulates both tumor intrinsic malignant properties as well as anti-tumor immune responses. Given the importance of hypoxia in glioblastoma (GBM) biology and particularly in shaping anti-tumor immunity, we analyzed which immunomodulatory genes are differentially regulated in response to hypoxia in GBM cells. Gene expression analyses identified the immunosuppressive enzyme tryptophan-2,3-dioxygenase (TDO2) as the second most downregulated gene in GBM cells cultured under hypoxic conditions. TDO2 catalyses the oxidation of tryptophan to N-formyl kynurenine, which is the first and rate-limiting step of Trp degradation along the kynurenine pathway (KP). In multiple GBM cell lines hypoxia reduced TDO2 expression both at mRNA and protein levels. The downregulation of TDO2 through hypoxia was reversible as re-oxygenation rescued TDO2 expression. Computational modeling of tryptophan metabolism predicted reduced flux through the KP and lower intracellular concentrations of kynurenine and its downstream metabolite 3-hydroxyanthranilic acid under hypoxia. Metabolic measurements confirmed the predicted changes, thus demonstrating the ability of the mathematical model to infer intracellular tryptophan metabolite concentrations. Moreover, we identified hypoxia inducible factor 1α (HIF1α) to regulate TDO2 expression under hypoxic conditions, as the HIF1α-stabilizing agents dimethyloxalylglycine (DMOG) and cobalt chloride reduced TDO2 expression. Knockdown of HIF1α restored the expression of TDO2 upon cobalt chloride treatment, confirming that HIF1α controls TDO2 expression. To investigate the immunoregulatory effects of this novel mechanism of TDO2 regulation, we co-cultured isolated T cells with TDO2-expressing GBM cells under normoxic and hypoxic conditions. Under normoxia TDO2-expressing GBM cells suppressed T cell proliferation, while hypoxia restored the proliferation of the T cells, likely due to the reduction in kynurenine levels produced by the GBM cells. Taken together, our data suggest that the regulation of TDO2 expression by HIF1α may be involved in modulating anti-tumor immunity in GBM. |
| first_indexed | 2024-12-12T03:04:44Z |
| format | Article |
| id | doaj.art-437c549b743549ddaac39ce7bbb130eb |
| institution | Directory Open Access Journal |
| issn | 1664-3224 |
| language | English |
| last_indexed | 2024-12-12T03:04:44Z |
| publishDate | 2019-12-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Immunology |
| spelling | doaj.art-437c549b743549ddaac39ce7bbb130eb2022-12-22T00:40:33ZengFrontiers Media S.A.Frontiers in Immunology1664-32242019-12-011010.3389/fimmu.2019.02762495924Hypoxia Inducible Factor 1α Inhibits the Expression of Immunosuppressive Tryptophan-2,3-Dioxygenase in GlioblastomaSoumya R. Mohapatra0Ahmed Sadik1Ahmed Sadik2Lars-Oliver Tykocinski3Jørn Dietze4Gernot Poschet5Ines Heiland6Christiane A. Opitz7Christiane A. Opitz8DKTK Brain Cancer Metabolism Group, German Cancer Research Center (DKFZ), Heidelberg, GermanyDKTK Brain Cancer Metabolism Group, German Cancer Research Center (DKFZ), Heidelberg, GermanyFaculty of Bioscience, Heidelberg University, Heidelberg, GermanyDivision of Rheumatology, Department of Medicine V, University Hospital of Heidelberg, Heidelberg, GermanyDepartment of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø, NorwayCentre for Organismal Studies (COS), University of Heidelberg, Heidelberg, GermanyDepartment of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø, NorwayDKTK Brain Cancer Metabolism Group, German Cancer Research Center (DKFZ), Heidelberg, GermanyNeurology Clinic and National Center for Tumor Diseases, University Hospital of Heidelberg, Heidelberg, GermanyAbnormal circulation in solid tumors results in hypoxia, which modulates both tumor intrinsic malignant properties as well as anti-tumor immune responses. Given the importance of hypoxia in glioblastoma (GBM) biology and particularly in shaping anti-tumor immunity, we analyzed which immunomodulatory genes are differentially regulated in response to hypoxia in GBM cells. Gene expression analyses identified the immunosuppressive enzyme tryptophan-2,3-dioxygenase (TDO2) as the second most downregulated gene in GBM cells cultured under hypoxic conditions. TDO2 catalyses the oxidation of tryptophan to N-formyl kynurenine, which is the first and rate-limiting step of Trp degradation along the kynurenine pathway (KP). In multiple GBM cell lines hypoxia reduced TDO2 expression both at mRNA and protein levels. The downregulation of TDO2 through hypoxia was reversible as re-oxygenation rescued TDO2 expression. Computational modeling of tryptophan metabolism predicted reduced flux through the KP and lower intracellular concentrations of kynurenine and its downstream metabolite 3-hydroxyanthranilic acid under hypoxia. Metabolic measurements confirmed the predicted changes, thus demonstrating the ability of the mathematical model to infer intracellular tryptophan metabolite concentrations. Moreover, we identified hypoxia inducible factor 1α (HIF1α) to regulate TDO2 expression under hypoxic conditions, as the HIF1α-stabilizing agents dimethyloxalylglycine (DMOG) and cobalt chloride reduced TDO2 expression. Knockdown of HIF1α restored the expression of TDO2 upon cobalt chloride treatment, confirming that HIF1α controls TDO2 expression. To investigate the immunoregulatory effects of this novel mechanism of TDO2 regulation, we co-cultured isolated T cells with TDO2-expressing GBM cells under normoxic and hypoxic conditions. Under normoxia TDO2-expressing GBM cells suppressed T cell proliferation, while hypoxia restored the proliferation of the T cells, likely due to the reduction in kynurenine levels produced by the GBM cells. Taken together, our data suggest that the regulation of TDO2 expression by HIF1α may be involved in modulating anti-tumor immunity in GBM.https://www.frontiersin.org/article/10.3389/fimmu.2019.02762/fullhypoxiaHIF1αtryptophanTDO2immunosuppression |
| spellingShingle | Soumya R. Mohapatra Ahmed Sadik Ahmed Sadik Lars-Oliver Tykocinski Jørn Dietze Gernot Poschet Ines Heiland Christiane A. Opitz Christiane A. Opitz Hypoxia Inducible Factor 1α Inhibits the Expression of Immunosuppressive Tryptophan-2,3-Dioxygenase in Glioblastoma Frontiers in Immunology hypoxia HIF1α tryptophan TDO2 immunosuppression |
| title | Hypoxia Inducible Factor 1α Inhibits the Expression of Immunosuppressive Tryptophan-2,3-Dioxygenase in Glioblastoma |
| title_full | Hypoxia Inducible Factor 1α Inhibits the Expression of Immunosuppressive Tryptophan-2,3-Dioxygenase in Glioblastoma |
| title_fullStr | Hypoxia Inducible Factor 1α Inhibits the Expression of Immunosuppressive Tryptophan-2,3-Dioxygenase in Glioblastoma |
| title_full_unstemmed | Hypoxia Inducible Factor 1α Inhibits the Expression of Immunosuppressive Tryptophan-2,3-Dioxygenase in Glioblastoma |
| title_short | Hypoxia Inducible Factor 1α Inhibits the Expression of Immunosuppressive Tryptophan-2,3-Dioxygenase in Glioblastoma |
| title_sort | hypoxia inducible factor 1α inhibits the expression of immunosuppressive tryptophan 2 3 dioxygenase in glioblastoma |
| topic | hypoxia HIF1α tryptophan TDO2 immunosuppression |
| url | https://www.frontiersin.org/article/10.3389/fimmu.2019.02762/full |
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