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.
PAX5 overexpression is not enough to reestablish the mature B-cell phenotype in classical Hodgkin lymphoma.
Cell line, Treatment
View SamplesBone marrow mesenchymal stem cells (MSC) were adipogenically differentiated followed by dedifferentiation. We are interested to know the new fat markers, adipogenic signaling pathways and dedifferentiation signaling pathways.Furthermore we are also intrested to know that how differentiated cells convert into dedifferentiated progenitor cells. To address these questions, MSC were adipogenically differentiated, followed by dedifferentiation. Finally these dedifferentiated cells were used for adipogenesis, osteogenesis and chondrogenesis. Histology, FACS, qPCR and GeneChip analyses of undifferentiated, adipogenically differentiated and dedifferentiated cells were performed. Regarding the conversion of adipogenically differentiated cells into dedifferentiated cells, gene profiling and bioinformatics demonstrated that upregulation (DHCR24, G0S2, MAP2K6, SESN3) and downregulation (DST, KAT2, MLL5, RB1, SMAD3, ZAK) of distinct genes play a curcial role in cell cycle to drive the adipogenically differentiated cells towards an arrested state to narrow down the lineage potency. However, the upregulation (CCND1, CHEK, HGF, HMGA2, SMAD3) and downregulation (CCPG1, RASSF4, RGS2) of these cell cycle genes motivates dedifferentiation of adipogenically differentiated cells to reverse the arrested state. We also found new fat markers along with signaling pathways for adipogenically differentiated and dedifferentiated cells, and also observed the influencing role of proliferation associated genes in cell cycle arrest and progression.
Transdifferentiation of adipogenically differentiated cells into osteogenically or chondrogenically differentiated cells: phenotype switching via dedifferentiation.
Specimen part
View SamplesAutologous chondrocyte transplantation (ACT) is a routine technique to regenerate focal cartilage lesions. However, patients with osteoarthritis (OA) are lacking an appropriate long-lasting treatment alternative, partly since it is not known if chondrocytes from OA patients have the same chondrogenic differentiation potential as chondrocytes from donors not affected by OA. Articular chondrocytes from patients with OA undergoing total knee replacement (Mankin Score >3, Ahlbck Score >2) and from patients undergoing ACT, here referred to as normal donors (ND), were isolated applying protocols used for ACT. Their chondrogenic differentiation potential was evaluated both in high-density pellet and scaffold (Hyaff-11) cultures by histological proteoglycan assessment (Bern Score) and immunohistochemistry for collagen types I and II. Chondrocytes cultured in monolayer and scaffolds were subjected to gene expression profiling using genome-wide oligonucleotide microarrays. Expression data were verified by using quantitative RT-PCR. Chondrocytes from ND and OA donors demonstrated accumulation of comparable amounts of cartilage matrix components, including sulphated proteoglycans and collagen types I and II. The mRNA expression of cartilage markers (COL2A1, COMP, aggrecan, CRTL1, SOX9) and genes involved in matrix synthesis (biglycan, COL9A2, COL11A1, TIMP4, CILP2) was highly induced in 3D cultures of chondrocytes from both donor groups. Genes associated with hypertrophic or OA cartilage (COL10A1, RUNX2, periostin, ALP, PTHR1, MMP13, COL1A1, COL3A1) were not significantly regulated between the two groups of donors. The expression of 661 genes, including COMP, FN1, and SOX9, were differentially regulated between OA and ND chondrocytes cultured in monolayer. During scaffold culture, the differences diminished between the OA and ND chondrocytes, and only 184 genes were differentially regulated. Only few genes were differentially expressed between OA and ND chondrocytes in Hyaff-11 culture. The risk of differentiation into hypertrophic cartilage does not seem to be increased for OA chondrocytes. Our findings suggest that the chondrogenic capacity is not significantly affected by OA and OA chondrocytes fulfill the requirements for matrix-associated ACT.
Chondrogenic differentiation potential of osteoarthritic chondrocytes and their possible use in matrix-associated autologous chondrocyte transplantation.
Specimen part
View SamplesA characteristic feature of anaplastic large cell lymphoma (ALCL) is the significant reduction of the T-cell expression program despite its T-cell origin, a finding very similar to the loss of B-cell identity of classical Hodgkin lymphoma (cHL). Previously we demonstrated that epigenetic mechanisms are active in cHL to induce this peculiar phenotype. The results show that combined DNA demethylation and histone acetylation of T-cell lines induce an almost complete extinction of the T-cell phenotype, including the down-regulation of essential T-cell receptor signalling pathway genes such as CD3, LCK and ZAP70, as well as an up-regulation of ALCL-characteristic genes. In contrast, combined DNA demethylation and histone acetylation of ALCL cells is not able to reconstitute their T-cell phenotype. This clearly demonstrates that similar epigenetic mechanisms are active in ALCL and cHL which are responsible for the extinction of their cell type characteristic phenotype.
Histone acetylation and DNA demethylation of T cells result in an anaplastic large cell lymphoma-like phenotype.
Specimen part, Cell line, Treatment
View SamplesAlternative mRNA splicing represents an effective mechanism of regulating gene function and is a key element to increase the coding capacity of the human genome. Today, an increasing number of reports illustrates that aberrant splicing events are common and functionally important for cancer development. However, more comprehensive analyses are warranted to get novel insights into the biology underlying malignancies like e.g. acute myeloid leukemia (AML). Here, we performed a genome-wide screening of splicing events in AML using an exon microarray platform. We analyzed complex karyotype and core binding factor (CBF) AML cases (n=64) in order to evaluate the ability to detect alternative splicing events distinguishing distinct leukemia subgroups. Testing different commercial and open source software tools to compare the respective AML subgroups, we could identify a large number of potentially alternatively spliced transcripts with a certain overlap of the different approaches. Selected candidates were further investigated by PCR and sequence analysis: out of 24 candidate genes studied, we could confirm alternative splice forms in 8 genes of potential pathogenic relevance, such as PRMT1 regulating transcription through histone methylation and participating in DNA damage response, and PTPN6, which encodes for a negative regulator of cell cycle control and apoptosis. In summary, this first large Exon microarray based study demonstrates that transcriptome splicing analysis in AML is feasible but challenging, in particular with regard to the currently available software solutions. Nevertheless, our results show that alternatively spliced candidate genes can be detected, and we provide a guide how to approach such analyses.
A robust estimation of exon expression to identify alternative spliced genes applied to human tissues and cancer samples.
Specimen part, Disease, Disease stage
View SamplesThis SuperSeries is composed of the SubSeries listed below.
An immediate-late gene expression module decodes ERK signal duration.
Specimen part, Cell line
View SamplesPurpose: In childhood acute lymphoblastic leukemia (ALL), approximately 25% of patients suffer from relapse. In recurrent disease, despite intensified therapy, overall cure rates of 40% remain unsatisfactory and survival rates are particularly poor in certain subgroups. The probability of long-term survival after relapse is predicted from well-established prognostic factors, i. e. time and site of relapse, immunophenotype and minimal residual disease. However, the underlying biological determinants of these prognostic factors remain poorly understood.
No associated publication
Sex
View SamplesBackground Published multi-gene classifiers suggested outcome prediction for patients with stage UICC II colon cancer based on different gene expression signatures. However, there is currently no translation of these classifiers for application in routine diagnostic. Therefore, we aimed at validating own and published gene expression signatures employing methods which enable RNA and protein detection in routine diagnostic specimens. Results Immunohistochemistry was applied to 68 stage UICC II colon cancers to determine the protein expression of five selected previously published classifier genes (CDH17, LAT, CA2, EMR3, and TNFRSF11A). Correlation of protein expression data with clinical outcome within a 5-year post-surgery course failed to separate patients with a disease-free follow-up [Group DF] and relapse [Group R]). In addition, RNA from macrodissected tumor samples from 53 of these 68 patients was profiled on Affymetrix GeneChips (HG-U133 Plus 2.0). Prognostic signatures were generated by Nearest Shrunken Centroids with cross-validation. Although gene expression profiling allowed the identification of differentially expressed genes between the groups DF and R, a stable classification and prognosis signature was not discernable in our data. Furthermore, the application of previously published gene signatures consisting of 22 and 19 genes, respectively, to our gene expression data set using global tests and leave-one-out cross-validation was unable to predict clinical outcome (prediction rate 75.5% and 64.2%; n.s.). T-stage was the only independent prognostic factor for relapse in multivariate analysis with established clinical and pathological parameters including microsatellite status. Conclusions Our protein and gene expression analyses currently do not support application of molecular classifiers for prediction of clinical outcome in routine diagnostic as a basis for patient-orientated therapy in stage UICC II colon cancer. Further studies are needed to develop prognosis signatures applicable in patient care.
Molecular profiles and clinical outcome of stage UICC II colon cancer patients.
Sex
View SamplesWe integrate experimental data and mathematical modelling to unveil how ERK signal duration is relayed to mRNA dynamics.
An immediate-late gene expression module decodes ERK signal duration.
Cell line
View SamplesRheumatoid arthritis (RA) accompanies infiltration and activation of monocytes in inflamed joints. In this study we investigated dominant alterations of RA monocytes in bone marrow (BM), blood and inflamed joints.
No associated publication
Sex, Specimen part, Disease
View Samples