Project description:The cellular microenvironment in classical Hodgkin lymphoma (cHL) is dominated by a mixed infiltrate of inflammatory cells with typically only about 1% Hodgkin and Reed/Sternberg (HRS) tumor cells. T cells are usually the largest population of cells in the cHL microenvironment, encompassing T helper (Th) cells, regulatory T (Treg) cells and cytotoxic T cells. Th and Treg cells presumably provide essential survival signals for HRS cells. Treg cells are also involved in rescuing HRS cells from anti-tumor immune responses. An understanding of the immune evasion strategies of HRS cells is not only highly relevant for a characterization of the pathophysiology of cHL, but also clinically, given the current treatment approaches targeting checkpoint inhibitors. Here, we characterized the cHL-specific CD4+ T cell infiltrate regarding its role in immune evasion. Global gene expression analysis of CD4+ Th and Treg cells isolated from cHL lymph nodes and reactive tonsils revealed that Treg cell signatures were enriched in CD4+ Th cells of cHL. Hence, HRS cells may induce a Treg differentiation in Th cells, which was supported by in vitro studies with Th cells and cHL cell lines. Furthermore, we found indication for immune-suppressive purinergic signaling and a role of the inhibitory receptor-ligand pairs BTLA-HVEM and CD200R-CD200 in promoting immune evasion. Taken together, this study reveals that the immune evasion strategies in cHL are even more complex and multifaceted than previously recognized.
Project description:Ophelia syndrome is characterized by the coincidence of severe neuropsychiatric symptoms, classical Hodgkin lymphoma, and the presence of antibodies to the metabotropic glutamate 5 receptor (mGluR5). Little is known about the pathogenetic link between these symptoms and the role anti-mGluR5-antibodies play. We investigated lymphoma tissue from patients with Ophelia syndrome and with isolated classical Hodgkin lymphoma by quantitative immunocytochemistry for mGluR5-expression. Further, we studied the L-1236, L-428, L-540, SUP-HD1, KM-H2, and HDLM-2 classical Hodgkin lymphoma cell lines by FACS and Western blot for mGluR5-expression, and by transcriptome analysis. mGluR5 surface expression differed significantly in terms of receptor density, distribution pattern, and percentage of positive cells. Highest levels were found in the L-1236 line. RNA-sequencing revealed more than 800 genes that were higher expressed in L-1236 in comparison to classical Hodgkin lymphoma-controls. High mGluR5-expression was associated with upregulation of PI3K/AKT and MAPK pathways and of downstream targets (e.g. EGR1) known to be involved in classical Hodgkin lymphoma progression. Finally, mGluR5 expression was increased in the classical Hodgkin lymphoma-tissue of our Ophelia syndrome patient in contrast to five classical Hodgkin lymphoma-patients without autoimmune encephalitis. Given the association of encephalitis and classical Hodgkin’s lymphoma in Ophelia syndrome, it is possible that mGluR5-expression on classical Hodgkin lymphoma cells not only drives tumor progression, but may also trigger anti-mGluR5 encephalitis already before classical Hodgkin lymphoma-manifestation.
Project description:Background Epigenetic changes are involved in the extinction of the B-cell gene expression program of classical Hodgkin lymphoma. However, little is known regarding epigenetic similarities between classical Hodgkin lymphoma and plasma cell myeloma cells, both of which share an extinction of the gene expression program of mature B-cells. Design and methods Global histone H3 acetylation patterns were determined in cell lines derived from classical Hodgkin lymphoma, plasma cell myeloma and B-cell lymphoma by chromatin immunoprecipitation and subsequent hybridization onto promoter tiling arrays. H3K27 trimethylation was analyzed by chromatin immunoprecipitation and real-time DNA-PCR for selected genes. Epigenetic modifications were compared to gene expression data. Results B-cell characteristic genes were hypoacetylated in classical Hodgkin lymphoma and plasma cell myeloma cell lines, as demonstrated by comparison of their histone H3 acetylation patterns to those of B-cell lines. However, the number of genes jointly hyperacetylated and expressed in classical Hodgkin lymphoma and plasma cell myeloma cell lines, such as IFR4/MUM1 and RYBP, is limited. Moreover, H3K27 trimethylation for selected B-cell characteristic genes revealed that this additional epigenetic silencing is much more prevalent in classical Hodgkin lymphoma as compared to plasma cell myeloma. Conclusion Our epigenetic data support the view that classical Hodgkin lymphoma is characterized by an abortive plasma cell differentiation with a down-regulation of B-cell characteristic genes but without activation of most plasma cell typical genes.
Project description:The pathogenesis of nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) and its relationship to other lymphomas are largely unknown. This is partly due to the technical challenge of analyzing its rare neoplastic L&H cells, which are dispersed in an abundant non-neoplastic cellular microenvironment. We performed a genome-wide expression study of microdissected lymphocytic and histiocytic (L&H) lymphoma cells in comparison to normal and other malignant B cells, which indicates a relationship of L&H cells to and/or origin from germinal center B cells at transition to memory B cells. L&H cells show a surprisingly high similarity to the tumor cells of T cell-rich B cell lymphoma and classical Hodgkin lymphoma, a partial loss of their B cell phenotype and deregulation of many apoptosis-regulators and putative oncogenes. Importantly, L&H cells are characterized by constitutive NF-κB activity and aberrant ERK signaling. Thus, these findings shed new light on the nature of L&H cells, revealed several novel pathogenetic mechanisms in NLPHL, and may help in differential diagnosis and lead to novel therapeutic strategies. Experiment Overall Design: Analysis of differential gene expression in primary human lymphoma cells of nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) in comparison with primary lymphoma cells of classical Hodgkin lymphoma cells and other B-non-Hodgkin lymphoma (B-NHL) samples and subsets of non-neoplastic B lymphocytes isolated from blood or tonsils. 67 gene expression profiles were analysed.
Project description:In lymphomas derived from mature B cells the expression of the transcription factor PAX5 is maintained whereas classical Hodgkin lymphoma displays significantly reduced PAX5 expression despite its derivation from mature B cells. To elucidate the functional role of PAX5 in classical Hodgkin lymphoma, we re-established the PAX5 expression in the Hodgkin cell line L428 with and without epigenetic modulation. To this end, we stably transfected the Hodgkin cell line L428 with an inducible PAX5 expression construct. Although the overexpressed PAX5 was transcriptionally active as demonstrated by synthetic reporter constructs, no induction of the B-cell phenotype was achieved. PAX5 chromatin immunoprecipitation with subsequent next generation sequencing in B-cell lines and the PAX5 overexpressing L428 cell line showed different binding patterns. Since epigenetic restrictions might affect PAX5 binding, combined DNA demethylation and histone acetylation was performed. However, no re-expression of B-cell genes was observed also under these conditions. Thus, PAX5 is not sufficient for the re-activation of the B-cell program in Hodgkin cells despite epigenetic opening of the chromatin. This clearly indicates that the repression of the B-cell identity of the Hodgkin cells is caused and secured by complex molecular mechanisms. Analysis of genome-wide PAX5 binding sites in B-cell lines (Raji, Namalwa) and the PAX5-producing Hodgkin cell line L428-PAX5 by ChIP-Seq
Project description:Background Epigenetic changes are involved in the extinction of the B-cell gene expression program of classical Hodgkin lymphoma. However, little is known regarding epigenetic similarities between classical Hodgkin lymphoma and plasma cell myeloma cells, both of which share an extinction of the gene expression program of mature B-cells. Design and methods Global histone H3 acetylation patterns were determined in cell lines derived from classical Hodgkin lymphoma, plasma cell myeloma and B-cell lymphoma by chromatin immunoprecipitation and subsequent hybridization onto promoter tiling arrays. H3K27 trimethylation was analyzed by chromatin immunoprecipitation and real-time DNA-PCR for selected genes. Epigenetic modifications were compared to gene expression data. Results B-cell characteristic genes were hypoacetylated in classical Hodgkin lymphoma and plasma cell myeloma cell lines, as demonstrated by comparison of their histone H3 acetylation patterns to those of B-cell lines. However, the number of genes jointly hyperacetylated and expressed in classical Hodgkin lymphoma and plasma cell myeloma cell lines, such as IFR4/MUM1 and RYBP, is limited. Moreover, H3K27 trimethylation for selected B-cell characteristic genes revealed that this additional epigenetic silencing is much more prevalent in classical Hodgkin lymphoma as compared to plasma cell myeloma. Conclusion Our epigenetic data support the view that classical Hodgkin lymphoma is characterized by an abortive plasma cell differentiation with a down-regulation of B-cell characteristic genes but without activation of most plasma cell typical genes. Gene expression analysis of Hodgkin lymphoma (cHL) and B-cell lines: Microarray data for three Hodgkin lymphoma cell lines (KM-H2, L1236, L428) and the B-cell line Namalwa that were published previously by our group (GEO accession GSE8388) were analyzed together with newly generated data for the B-cell lines SU-DHL4 and SU-DHL6. For all cell lines, RNA was isolated according to standard protocols (Qiagen, Hilden, Germany) and used for Affymetrix GeneChip hybridization (HG-U133A). Microarrays were normalized using RMA, and differential expression was calculated using moderated t-test. The gene expression profiles of the cell lines were generated in duplicates.
Project description:Background Epigenetic changes are involved in the extinction of the B-cell gene expression program of classical Hodgkin lymphoma. However, little is known regarding epigenetic similarities between classical Hodgkin lymphoma and plasma cell myeloma cells, both of which share an extinction of the gene expression program of mature B-cells. Design and methods Global histone H3 acetylation patterns were determined in cell lines derived from classical Hodgkin lymphoma, plasma cell myeloma and B-cell lymphoma by chromatin immunoprecipitation and subsequent hybridization onto promoter tiling arrays. H3K27 trimethylation was analyzed by chromatin immunoprecipitation and real-time DNA-PCR for selected genes. Epigenetic modifications were compared to gene expression data. Results B-cell characteristic genes were hypoacetylated in classical Hodgkin lymphoma and plasma cell myeloma cell lines, as demonstrated by comparison of their histone H3 acetylation patterns to those of B-cell lines. However, the number of genes jointly hyperacetylated and expressed in classical Hodgkin lymphoma and plasma cell myeloma cell lines, such as IFR4/MUM1 and RYBP, is limited. Moreover, H3K27 trimethylation for selected B-cell characteristic genes revealed that this additional epigenetic silencing is much more prevalent in classical Hodgkin lymphoma as compared to plasma cell myeloma. Conclusion Our epigenetic data support the view that classical Hodgkin lymphoma is characterized by an abortive plasma cell differentiation with a down-regulation of B-cell characteristic genes but without activation of most plasma cell typical genes.
Project description:Background Epigenetic changes are involved in the extinction of the B-cell gene expression program of classical Hodgkin lymphoma. However, little is known regarding epigenetic similarities between classical Hodgkin lymphoma and plasma cell myeloma cells, both of which share an extinction of the gene expression program of mature B-cells. Design and methods Global histone H3 acetylation patterns were determined in cell lines derived from classical Hodgkin lymphoma, plasma cell myeloma and B-cell lymphoma by chromatin immunoprecipitation and subsequent hybridization onto promoter tiling arrays. H3K27 trimethylation was analyzed by chromatin immunoprecipitation and real-time DNA-PCR for selected genes. Epigenetic modifications were compared to gene expression data. Results B-cell characteristic genes were hypoacetylated in classical Hodgkin lymphoma and plasma cell myeloma cell lines, as demonstrated by comparison of their histone H3 acetylation patterns to those of B-cell lines. However, the number of genes jointly hyperacetylated and expressed in classical Hodgkin lymphoma and plasma cell myeloma cell lines, such as IFR4/MUM1 and RYBP, is limited. Moreover, H3K27 trimethylation for selected B-cell characteristic genes revealed that this additional epigenetic silencing is much more prevalent in classical Hodgkin lymphoma as compared to plasma cell myeloma. Conclusion Our epigenetic data support the view that classical Hodgkin lymphoma is characterized by an abortive plasma cell differentiation with a down-regulation of B-cell characteristic genes but without activation of most plasma cell typical genes.
Project description:Background Epigenetic changes are involved in the extinction of the B-cell gene expression program of classical Hodgkin lymphoma. However, little is known regarding epigenetic similarities between classical Hodgkin lymphoma and plasma cell myeloma cells, both of which share an extinction of the gene expression program of mature B-cells. Design and methods Global histone H3 acetylation patterns were determined in cell lines derived from classical Hodgkin lymphoma, plasma cell myeloma and B-cell lymphoma by chromatin immunoprecipitation and subsequent hybridization onto promoter tiling arrays. H3K27 trimethylation was analyzed by chromatin immunoprecipitation and real-time DNA-PCR for selected genes. Epigenetic modifications were compared to gene expression data. Results B-cell characteristic genes were hypoacetylated in classical Hodgkin lymphoma and plasma cell myeloma cell lines, as demonstrated by comparison of their histone H3 acetylation patterns to those of B-cell lines. However, the number of genes jointly hyperacetylated and expressed in classical Hodgkin lymphoma and plasma cell myeloma cell lines, such as IFR4/MUM1 and RYBP, is limited. Moreover, H3K27 trimethylation for selected B-cell characteristic genes revealed that this additional epigenetic silencing is much more prevalent in classical Hodgkin lymphoma as compared to plasma cell myeloma. Conclusion Our epigenetic data support the view that classical Hodgkin lymphoma is characterized by an abortive plasma cell differentiation with a down-regulation of B-cell characteristic genes but without activation of most plasma cell typical genes.