| 1. |
- Kis, Loránd Levente
(författare)
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The role of the microenvironment on the regulation of Epstein-Barr virus latent gene expression
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Epstein-Barr virus (EBV) is a human-specific gamma-herpes virus of the Lymphocryptovirus genus that has succeeded to colonize more than 90% of the adult population. EBV s coevolution with humans has established a largely harmless co-existence that depends on the variability of viral gene expression and on the immunological host response. Though infection with EBV is generally harmless, the virus is associated with multiple human tumors, such as Burkitt lymphoma, classical Hodgkin lymphoma, nasopharyngeal carcinoma, post-transplant lymphoproliferative disorders, and AIDS lymphomas. The role of EBV in the malignant transformation is still enigmatic even after more than 40 years of research on this virus. EBV readily infects B-lymphocytes in vitro. After infection the virus establishes a latent infection and expresses 9 viral proteins. The concerted effect of these EBV proteins will be the activation and proliferation of the infected B cells. This viral gene expression pattern was named type III latency. As the EBV-infected B cells with type III latency are highly immunogenic they are readily detected and killed by the specific cytotoxic T cells. In contrast to the EBV-infected normal B cells, the majority of the EBV-carrying tumors do not express all the nine proteins; rather they express only EBNA-1 or EBNA-1 together with the latent membrane proteins (LMP-1 and LMP-2). The factors that determine what viral genes EBV will express in the different normal and malignant cells are only partially known. Motivated by the lack of in vitro models in which to study the interaction of EBV with the malignant Hodgkin/Reed-Sternberg (HRS) cells, we infected with EBV one of the Hodgkin lymphoma-derived cell lines and studied the viral gene expression in this EBV-converted subline. In this system we identified two cytokines, IL-4 and IL-13, that could modulate the viral gene expression (specifically, induce the expression of LMP-1) and with their help we could for the first time reconstitute in vitro the EBV gene expression seen in the classical Hodgkin lymphomas in vivo. We have also studied the molecular mechanisms that are responsible for the induction of LMP-1 by IL-4 and IL-13. Through these studies we identified STAT6 as an important inducer of LMP-1 expression. As STAT6 is constitutively activated in the majority of Hodgkin lymphomas, our results not only provides an explanation how LMP-1 is expressed in the EBV-carrying HRS cells, but might also have future therapeutic implications. Further work identified two additional cytokines, IL-10 and IL-21, which could induce the expression of LMP-1 in EBV-positive B cell and NK cell lymphoma-derived cell lines. The effect of IL-21 was pleiotropic: it could induce LMP-1 in cells that did not express it, and it induced the plasma cell differentiation and down-regulation of expression of the EBV nuclear antigens (EBNA-1 to -6) in type III lymphoblastoid and Burkitt lymphoma cell lines. Furthermore, when isolated human CD4+ T cells were co-cultured with different EBVcarrying lymphoma cell lines, we found that upon activation they were capable of inducing the expression of LMP-1, just as the recombinant cytokines did. Altogether our results provide evidence for an important role for the cytokines secreted by CD4+ T or other inflammatory cells in the modulation of EBV latent gene expression.
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| 2. |
- Kis, Loránd L., et al.
(författare)
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The STAT6 signaling pathway activated by the cytokines IL-4 and IL-13 induces expression of the Epstein-Barr virus-encoded protein LMP-1 in absence of EBNA-2 : implications for the type II EBV latent gene expression in Hodgkin lymphoma
- 2011
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Ingår i: Blood. - : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 117:1, s. 165-174
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Tidskriftsartikel (refereegranskat)abstract
- In line with the B-lymphotropic nature of EBV, the virus is present in several types of B cell lymphomas. EBV expresses a different set of latent genes in the associated tumors, such as EBNA-1 and LMPs (type II latency) in the classical Hodgkin lymphomas (cHL). We have previously reported that exposure of the in vitro EBV-converted, HL-derived cell line KMH2-EBV to CD40-ligand and IL-4 induced the expression of LMP-1. Here we show that exposure to IL-4 or IL-13 alone induced LMP-1 in the absence of EBNA-2. The induction of LMP-1 by IL-4 and IL-13 was mediated by the signal transducer STAT6 and a newly defined high-affinity STAT6-binding site in the LMP-1 promoter. IL-4 induced LMP-1 also in Burkitt lymphoma-derived lines and in tonsillar B cells infected with the EBNA-2-deficient EBV strain P3HR-1. Furthermore, co-culture of EBV-carrying BL cells with activated CD4(+) T cells resulted in the induction of LMP-1 in the absence of EBNA-2. As the Hodgkin/Reed-Sternberg are known to secrete IL-13, to have constitutively activated STAT6, and to be closely surrounded by CD4+ T cells, these mechanisms may be involved in the expression of LMP-1 in the EBV-positive cHLs.
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| 3. |
- Montero, Angeles M., et al.
(författare)
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Clinicopathological significance of the expression of PD-L1 in Non-Small Cell Lung Cancer
- 2021
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Ingår i: Annals of Diagnostic Pathology. - : Elsevier BV. - 1092-9134 .- 1532-8198. ; 51, s. 151701-
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: PD1/PD-L1 pathway targeting therapies are nowadays an established treatment option for patients with NSCLC. We assessed whether PD-L1 expression in NSCLC tumor cells was associated with specific clinical features or overall survival using four different clones. Methods and results: A retrospective study included formalin-fixed paraffin embedded (FFPE) surgical tumors from 482 patients. PD-L1 status was assessed with immunohistochemistry in tumor cells on tissue microarrays using clones 28-8, 22C3, SP263 and SP142. Associations with OS were assessed by Kaplan-Meier and multivariate Cox's regression analysis. Patients' median age: 68 years (39–86); histology: adenocarcinoma (AdCa) 61%, squamous-cell carcinoma (SqCC) 33%, and large cell carcinoma (LCC) 6%; p-stage: IA (46%), IB (30%), IIA (10%), IIB (11,4%), IIIA (1,2%), IIIB – IV (0,4%). PD-L1 positivity (≥1%) in NSCLC for clones 28-8, 22C3, SP263, SP142 was 41.5%, 34.2%, 42.7%, 10.4%, respectively (Pearson Chi-square p < 0.0001). PD-L1 expression was correlated with histology, tumor size and grading. Statistically significant association between PD-L1 expression and OS in NSCLC and Non-AdCa was observed with clone SP142 (log-rank p = 0.045 and p = 0.05, respectively). Statistically significant association between PD-L1 expression and OS in LCC was observed with clones 22C3 (log-rank p = 0.009) and SP263 (log-rank p = 0.050). Conclusions: Overexpression of the PD-L1 clone SP142 was associated with poor overall survival in NSCLC and Non-AdCa. Clones 22C3 and SP263 were associated with poor prognosis in LCC. PD-L1 status might serve as a prognostic marker in NSCLC.
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| 4. |
- Nagy, Noémi, et al.
(författare)
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The proapoptotic function of SAP provides a clue to the clinical picture of X-linked lymphoproliferative disease
- 2009
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 106:29, s. 11966-11971
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Tidskriftsartikel (refereegranskat)abstract
- Deletion or mutation of the SAP gene is associated with the X-linked lymphoproliferative disease (XLP) that is characterized by extreme sensitivity to Epstein-Barr virus (EBV). Primary infection of the affected individuals leads to serious, sometimes fatal infectious mononucleosis (IM) and proneness to lymphoma. Our present results revealed a proapoptotic function of SAP by which it contributes to the maintenance of T-cell homeostasis and to the elimination of potentially dangerous DNA-damaged cells. Therefore, the loss of this function could be responsible for the uncontrolled T-cell proliferation in fatal IM and for the generation of lymphomas. We show now the role of SAP in apoptosis in T and B lymphocyte-derived lines. Among the clones of T-ALL line, the ones with higher SAP levels succumbed more promptly to activation induced cell death (AICD). Importantly, introduction of SAP expression into lymphoblastoid cell lines (LCL) established from XLP patients led to elevated apoptotic response to DNA damage. Similar results were obtained in the osteosarcoma line, Saos-2. We have shown that the anti-apoptotic protein VCP (valosin-containing protein) binds to SAP, suggesting that it could be instrumental in the enhanced apoptotic response modulated by SAP.
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| 5. |
- Rantalainen, Mattias, et al.
(författare)
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Sequencing-based breast cancer diagnostics as an alternative to routine biomarkers
- 2016
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Ingår i: Scientific Reports. - Stockholm : Karolinska Institutet, Dept of Medical Epidemiology and Biostatistics. - 2045-2322.
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Tidskriftsartikel (refereegranskat)abstract
- Sequencing-based breast cancer diagnostics have the potential to replace routine biomarkers and provide molecular characterization that enable personalized precision medicine. Here we investigate the concordance between sequencing-based and routine diagnostic biomarkers and to what extent tumor sequencing contributes clinically actionable information. We applied DNA- and RNA-sequencing to characterize tumors from 307 breast cancer patients with replication in up to 739 patients. We developed models to predict status of routine biomarkers (ER, HER2,Ki-67, histological grade) from sequencing data. Non-routine biomarkers, including mutations in BRCA1, BRCA2 and ERBB2(HER2), and additional clinically actionable somatic alterations were also investigated. Concordance with routine diagnostic biomarkers was high for ER status (AUC = 0.95;AUC(replication) = 0.97) and HER2 status (AUC = 0.97;AUC(replication) = 0.92). The transcriptomic grade model enabled classification of histological grade 1 and histological grade 3 tumors with high accuracy (AUC = 0.98;AUC(replication) = 0.94). Clinically actionable mutations in BRCA1, BRCA2 and ERBB2(HER2) were detected in 5.5% of patients, while 53% had genomic alterations matching ongoing or concluded breast cancer studies. Sequencing-based molecular profiling can be applied as an alternative to histopathology to determine ER and HER2 status, in addition to providing improved tumor grading and clinically actionable mutations and molecular subtypes. Our results suggest that sequencing-based breast cancer diagnostics in a near future can replace routine biomarkers
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| 6. |
- Salmon, Daniel, et al.
(författare)
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Type I interferons directly down-regulate BCL-6 in primary and transformed germinal center B cells : Differential regulation in B cell lines derived from endemic or sporadic Burkitt's lymphoma
- 2012
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Ingår i: Cytokine. - : Elsevier BV. - 1043-4666 .- 1096-0023. ; 57:3, s. 360-371
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Tidskriftsartikel (refereegranskat)abstract
- Type I interferons (IFN) exert multiple effects on both the innate and adaptive immune system in addition to their antiviral and antiproliferative activities. Little is known, however about the direct effects of type IFNs on germinal center (GC) B cells, the central components of adaptive B cell responses. We used Burkitt's lymphoma (BL) lines, as a model system of normal human GC B cells, to examine the effect of type I IFNs on the expression of BCL-6, the major regulator of the GC reaction. We show that type I IFNs, but not IFN gamma, IL-2 and TNF alpha rapidly down-regulate BCL-6 protein and mRNA expression, in cell lines derived from endemic, but not from sporadic BL. IFN alpha-induced down-regulation is specific for BCL-6, independent of Epstein-Barr virus and is not accompanied by IRF-4 up-regulation. IFN alpha-induced BCL-6 mRNA down-regulation does not require de novo protein synthesis and is specifically inhibited by piceatannol. The proteasome inhibitor mG132 non-specifically prevents, while inhibitors of alternate type I IFN signaling pathways do not inhibit IFNa-induced BCL-6 protein downregulation. We validate our results with showing that IFN alpha rapidly down-regulates BCL-6 mRNA in purified mouse normal GC B cells. Our results identify type I IFNs as the first group of cytokines that can down-regulate BCL-6 expression directly in GC B cells.
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| 7. |
- Tanaka, Nobuyuki, et al.
(författare)
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Whole-tissue biopsy phenotyping of three-dimensional tumours reveals patterns of cancer heterogeneity
- 2017
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Ingår i: Nature Biomedical Engineering. - : Nature Publishing Group. - 2157-846X. ; 1:10, s. 796-806
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Tidskriftsartikel (refereegranskat)abstract
- Intratumoral heterogeneity is a critical factor when diagnosing and treating patients with cancer. Marked differences in the genetic and epigenetic backgrounds of cancer cells have been revealed by advances in genome sequencing, yet little is known about the phenotypic landscape and the spatial distribution of intratumoral heterogeneity within solid tumours. Here, we show that three-dimensional light-sheet microscopy of cleared solid tumours can identify unique patterns of phenotypic heterogeneity, in the epithelial-to-mesenchymal transition and in angiogenesis, at single-cell resolution in whole formalin-fixed paraffin-embedded (FFPE) biopsy samples. We also show that cleared FFPE samples can be re-embedded in paraffin after examination for future use, and that our tumour-phenotyping pipeline can determine tumour stage and stratify patient prognosis from clinical samples with higher accuracy than current diagnostic methods, thus facilitating the design of more efficient cancer therapies.
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