Diffuse large B-cell lymphoma (DLBCL) represents a heterogeneous diagnostic category with distinct molecular subtypes that can be defined by gene expression profiling. However, even within these defined subtypes, heterogeneity prevails. To further elucidate the pathogenesis of these entities, we determined the expression of the tumor suppressor phosphatase and tensin homolog (PTEN) in 248 primary DLBCL patient samples. These analyses revealed that loss of PTEN was detectable in 55% of germinal center B-cell-like (GCB) DLBCLs, whereas this abnormality was found in only 14% of non-GCB DLBCL patient samples. In GCB DLBCL, the PTEN status was inversely correlated with activation of the oncogenic PI3K/ protein kinase B (AKT) pathway in both DLBCL cell lines and primary patient samples. Re-expression of PTEN induced cytotoxicity in PTEN-deficient GCB DLBCL cell line models by inhibiting PI3K/AKT signaling, indicating an addiction to this pathway in this subset of GCB DLBCLs. PI3K/AKT inhibition induced down-regulation of the transcription factor MYC. Re-expression of MYC rescued GCB DLBCL cells from PTEN-induced toxicity, identifying a regulatory mechanism of MYC expression in DLBCL. Finally, pharmacologic PI3K inhibition resulted in toxicity selectively in PTEN-deficient GCB DLBCL lines. Collectively, our results indicate that PTEN loss defines a PI3K/ AKT-dependent GCB DLBCL subtype that is addicted to PI3K and MYC signaling and suggest that pharmacologic inhibition of PI3K might represent a promising therapeutic approach in these lymphomas.
PTEN loss defines a PI3K/AKT pathway-dependent germinal center subtype of diffuse large B-cell lymphoma.
Sex, Disease, Cell line, Treatment
View SamplesThis SuperSeries is composed of the SubSeries listed below.
IκB-ζ controls the constitutive NF-κB target gene network and survival of ABC DLBCL.
Cell line, Treatment
View SamplesConstitutive activation of the nuclear factor-kappa B (NF-kB) pathway is a hallmark of the activated B-cell-like (ABC) subtype of diffuse large B-cell lymphoma (DLBCL). Recurrent mutations of NF-kB regulators that cause constitutive activity of this oncogenic pathway have been identified. However, it remains unclear how specific target genes are regulated. We identified the IkB-like protein NFKBIZ that binds NF-kB subunits and enhances transactivation of some NF-kB target genes while repressing others, to be upregulated in ACB compared to GCB DLBCL primary patient samples (p=5.1 x 10^-37). Knockdown of NFKBIZ by RNA interference was toxic to ABC but not GCB DLBCL cell lines. Gene expression profiling following NFKBIZ knockdown significantly downregulated a large number of NF-kB target genes, suggesting a central role in regulating NF-kB signaling. To further investigate the molecular mechanisms of how NFKBIZ mediates NF-kB signaling in ABC DLBCL, we performed immunoprecipitations and detected an interaction of NFKBIZ with both p50 and p52 NF-kB subunits, indicating that both the canonical and non-canonical NF-kB pathways are regulated by NFKBIZ. Collectively, our data imply that NFKBIZ is required for NF-kB signaling in ABC DLBCL and thus might represent a promising molecular target for future therapies.
IκB-ζ controls the constitutive NF-κB target gene network and survival of ABC DLBCL.
Cell line
View SamplesConstitutive activation of the nuclear factor-kappa B (NF-kB) pathway is a hallmark of the activated B-cell-like (ABC) subtype of diffuse large B-cell lymphoma (DLBCL). Recurrent mutations of NF-kB regulators that cause constitutive activity of this oncogenic pathway have been identified. However, it remains unclear how specific target genes are regulated. We identified the IkB-like protein NFKBIZ that binds NF-kB subunits and enhances transactivation of some NF-kB target genes while repressing others, to be upregulated in ACB compared to GCB DLBCL primary patient samples (p=5.1 x 10^-37). Knockdown of NFKBIZ by RNA interference was toxic to ABC but not GCB DLBCL cell lines. Gene expression profiling following NFKBIZ knockdown significantly downregulated a large number of NF-kB target genes, suggesting a central role in regulating NF-kB signaling. To further investigate the molecular mechanisms of how NFKBIZ mediates NF-kB signaling in ABC DLBCL, we performed immunoprecipitations and detected an interaction of NFKBIZ with both p50 and p52 NF-kB subunits, indicating that both the canonical and non-canonical NF-kB pathways are regulated by NFKBIZ. Collectively, our data imply that NFKBIZ is required for NF-kB signaling in ABC DLBCL and thus might represent a promising molecular target for future therapies.
IκB-ζ controls the constitutive NF-κB target gene network and survival of ABC DLBCL.
Cell line, Treatment
View SamplesThree ALCL cell lines DEL, FEPD and K299 were induced with an IRF4-specific shRNA for up to 96 hours.
Essential role of IRF4 and MYC signaling for survival of anaplastic large cell lymphoma.
Cell line
View SamplesMantle cell lymphoma (MCL) is a mature B-cell lymphoma characterized by poor clinical outcome. Recent studies revealed the importance of BCR signaling in maintaining MCL survival. However, it remains unclear which role MALT1, an essential component of the CARD11-BCL10-MALT1 (CBM) complex that transfers BCR signaling to the NF-kB pathway, plays in the biology of MCL. Here we show that a subset of MCLs is addicted to MALT1, as its inhibition by either RNA or pharmacologic interference induced cytotoxicity both in vitro and in vivo. Gene expression profiling following MALT1 inhibition demonstrated that MALT1 controls a MYC-driven gene expression network predominantly through increased MYC protein stability. Thus our analyses identify a previously unappreciated regulatory mechanism of MYC expression. Investigating primary mouse splenocytes, we could demonstrate that MALT1 induced MYC regulation is not restricted to MCL, but represents a common mechanism of MYC regulation. MYC itself is pivotal for MCL survival as its downregulation and pharmacologic inhibition induced cytotoxicity in all MCL models. Collectively, these results provide a strong mechanistic rationale to investigate the therapeutic efficacy in targeting the MALT1-MYC axis in MCL patients.
B-cell receptor-driven MALT1 activity regulates MYC signaling in mantle cell lymphoma.
Specimen part, Cell line
View SamplesExposure to ultraviolet (UV) irradiation is the major cause of nonmelanoma skin cancer, the most common form of cancer in the United States. UV irradiation has a variety of effects on the skin associated with carcinogenesis, including DNA damage and effects on signal transduction. The alterations in signaling caused by UV regulate inflammation, cell proliferation, and apoptosis. UV also activates the orphan receptor tyrosine kinase and proto-oncogene Erbb2 (HER2/neu). In this study, we demonstrate that the UV-induced activation of Erbb2 regulates the response of the skin to UV. Inhibition or knockdown of Erbb2 before UV irradiation suppressed cell proliferation, cell survival, and inflammation after UV. In addition, Erbb2 was necessary for the UV-induced expression of numerous proinflammatory genes that are regulated by the transcription factors nuclear factor-kappaB and Comp1, including interleukin-1beta, prostaglandin-endoperoxidase synthase 2 (Cyclooxygenase-2), and multiple chemokines. These results reveal the influence of Erbb2 on the UV response and suggest a role for Erbb2 in UV-induced pathologies such as skin cancer.
Erbb2 regulates inflammation and proliferation in the skin after ultraviolet irradiation.
No sample metadata fields
View SamplesHuman subjects were randomized for treatment with a GnRH-analogue, Goserelin, which suppresses endogenous testosterone or placebo for 12 weeks. Strength training was performed during the last 8 weeks. The suppression of testosterone resulted in an attenuation of the normal muscle adaptation to strength training (increased muscle mass and strength). To identify molecular signals involved in the response to testosterone levels, biopsies were obtained 4 hours after the last training session and gene expression compared with Affymetrix 3' microarrays. This timepoint should capture goserelin effect on both constitutive expression, training induced changes as well as acute exercise induced (4 hours) differences in mRNA levels.
The activity of satellite cells and myonuclei following 8 weeks of strength training in young men with suppressed testosterone levels.
Sex, Age, Specimen part, Treatment
View SamplesWe applied RNA sequencing (RNA-seq) to map the global changes in gene expression of interscapular brown adipose tissue (iBAT) of mice subjected to acute cold exposure for 3 days. Here we find extensive changes in the iBAT transcriptome in response to cold with a prominent induction of genes associated to lipid-related metabolic processes. Overall design: RNA-seq of poly-A enriched RNA isolated from brown adipose tissue of 5 mice housed at room temperature (22°C) and 5 mice exposed to cold (4°C) for 3 days.
RNA-Seq and Mass-Spectrometry-Based Lipidomics Reveal Extensive Changes of Glycerolipid Pathways in Brown Adipose Tissue in Response to Cold.
No sample metadata fields
View SamplesDespite over 3,000 articles published on dystrophin in the last 15 years, the reasons underlying the progression of the human disease, differential muscle involvement, and disparate phenotypes in different species are not understood. The present experiment employed a screen of 12,488 mRNAs in 16-wk-old mouse mdx muscle at a time when the skeletal muscle is avoiding severe dystrophic pathophysiology, despite the absence of a functional dystrophin protein. A number of transcripts whose levels differed between the mdx and human Duchenne muscular dystrophy were noted. A fourfold decrease in myostatin mRNA in the mdx muscle was noted. Differential upregulation of actin-related protein 2/3 (subunit 4), beta-thymosin, calponin, mast cell chymase, and guanidinoacetate methyltransferase mRNA in the more benign mdx was also observed. Transcripts for oxidative and glycolytic enzymes in mdx muscle were not downregulated. These discrepancies could provide candidates for salvage pathways that maintain skeletal muscle integrity in the absence of a functional dystrophin protein in mdx skeletal muscle.
Regenerated mdx mouse skeletal muscle shows differential mRNA expression.
No sample metadata fields
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