Protein homeostasis in the endoplasmic reticulum (ER) has recently emerged as a therapeutic target for cancer treatment. Disruption of ER homeostasis results in ER stress, which is a major cause of cell death for cells exposed to the proteasome inhibitor Bortezomib, an anti-cancer drug approved for treatment of multiple myeloma and Mantle cell lymphoma. We recently reported that the ERAD inhibitor Eeyarestatin I (EerI) also disturbs ER homeostasis and has anti-cancer activities resembling that of Bortezomib.
The ERAD inhibitor Eeyarestatin I is a bifunctional compound with a membrane-binding domain and a p97/VCP inhibitory group.
Cell line
View SamplesThe ubiquitin-proteasome system (UPS) has recently emerged as a major target for drug development in cancer therapy. The proteasome inhibitor bortezomib has clinical activity in multiple myeloma and mantle cell lymphoma. Here we report that Eeyarestatin I (EerI), a chemical inhibitor that blocks ER-associated protein degradation (ERAD), has anti-tumor and biologic activities similar to bortezomib, and can synergize with bortezomib. Like bortezomib, EerI-induced cytotoxicity requires the upregulation of the BH3 only pro-apoptotic protein NOXA. We further demonstrate that both EerI and bortezomib activate NOXA via an unanticipated mechanism that requires cooperation between two processes: First, these agents elicit an integrated stress response program at the ER to activate the CREB/ATF transcription factors ATF3 and ATF4. We show that ATF3 and ATF4 form a complex capable of binding to the NOXA promoter, which is required for NOXA activation. Second, EerI and bortezomib also block ubiquitination of histone H2A to relieve its inhibition on NOXA transcription. Our results identify a class of anti-cancer agents that integrate ER stress response with an epigenetic mechanism to induce cell death.
ERAD inhibitors integrate ER stress with an epigenetic mechanism to activate BH3-only protein NOXA in cancer cells.
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View SamplesWe provide direct in vivo evidence for activation of the BCR and canonical NF-KB pathways in MCL that, in the absence of activating mutations, is dependent on the lymph node microenvironment.
Pathogenic role of B-cell receptor signaling and canonical NF-κB activation in mantle cell lymphoma.
Specimen part
View SamplesWe provide direct in vivo evidence for activation of the BCR and canonical NF-KB pathways in MCL that, in the absence of activating mutations, is dependent on the lymph node microenvironment. This finding provides a mechanistic explanation for the surprising efficacy of ibrutinib for the treatment of this type of lymphoma. Mutations in components of the BCR and NF-KB pathways are associated with cell-autonomous signaling and resistance to ibrutinib. Overall design: Lymph node biopsies and peripheral blood samples were obtained from patients with previously untreated MCL.
Pathogenic role of B-cell receptor signaling and canonical NF-κB activation in mantle cell lymphoma.
No sample metadata fields
View SamplesBortezomib-induced resistant MCL cell lines (HBL2 BR and JEKO BR) were generated by continuous cultured of corresponding parental cell lines (HBL2 PT and JEKO PT) with increasing bortezomib concentrations
Bortezomib resistance in mantle cell lymphoma is associated with plasmacytic differentiation.
Specimen part, Cell line
View SamplesMantle Cell Lymphoma (MCL) is a mostly incurable malignancy arising from nave B cells (NBC) in the mantle zone of lymph node follicles. We analyzed genome-wide methylation in MCL patients using the HELP (Hpa II tiny fragment Enrichment by Ligation mediated PCR) assay and found significant aberrancy in promoter methylation patterns as compared to normal NBCs. Using biological and stringent statistical criteria, we further identified four hypermethylated genes CDKN2B, MLF-1, PCDH8, HOXD8 and four hypomethylated genes CD37, HDAC1, NOTCH1 and CDK5 where aberrant methylation was associated with inverse changes in mRNA levels. MassArray Epityper analysis confirmed the presence of differential methylation at the promoter region of these genes. Immunohistochemical analysis of an independent cohort of 14 MCL patient samples, confirmed CD37 surface expression in 93% of patients, validating its selection as a target for MCL therapy. Treatment of MCL cell lines with a novel small modular immunopharmaceutical(CD37-SMIP) resulted in significant loss of viability in cell lines with intense surface CD37 expression. Treatment of MCL cell lines with the DNA methyltransferase inhibitor decitabine resulted in reversal of aberrant hypermethylation and synergized with the HDAC inhibitor SAHA in induction of the four hypermethylated genes CDKN2B, MLF-1, PCDH8 and HOXD8. The combination of Decitabine and SAHA also resulted in potent and synergistic anti-MCL cytotoxicity as compared to either drug alone. In conclusion, our analysis shows prominent and aberrant methylation of the MCL genome and identifies novel differentially methylated and expressed genes in MCL cell lines and patient samples. Furthermore, our data suggest that differentially methylated genes can be targeted for therapeutic benefit in MCL.
Genomewide DNA methylation analysis reveals novel targets for drug development in mantle cell lymphoma.
Disease, Cell line
View SamplesThe Early Growth Response (Egr) family of transcription factors consists of 4 members (Egr1-4) that are expressed in a wide variety of cell types. A large body of evidence point to a role for Egr transcription factors in growth, survival, and differentiation. A major unanswered question is whether Egr transcription factors serve similar functions in diverse cell types by activating a common set of target genes. Signal transduction cascades in neurons and lymphocytes show striking parallels. Activation of either cell type activates the Ras-MAPK pathway and, in parallel, leads to increases in intracellular calcium stimulating the calcineurin-NFAT pathway. In both cell types, the strength of the activation signal affects the cellular outcomes and very strong stimuli lead to cell death. Notably both these pathways converge on the induction of Egr genes. We believe that downstream targets of Egr transcription factors in lymphocytes may also be activated by Egr factors in activated neurons. There is precedence for common target gene activation in these two cell types: apoptosis in both activated T cells and methamphetamine stimulated neurons occurs via FasL induction by NFAT transcription factors. We propose to use developing T lymphocytes (thymocytes) as a model system for discovery of Egr-dependent target genes for several reasons. First, we have observed a prominent survival defect in thymocytes from mice deficient in both Egr1 and Egr3 (1/3 DKO) and a partial differention block in the immature double negative (DN) stage. In addition, thymocytes are an easily manipulatable cell type, and the DN subpopulation affected in 1/3 DKO mice can be isolated to very high purity. We anticipate that 1/3 DKO thymocytes will provide an excellent experimental system that will provide insight into Egr-dependent transcription in neuronal development, activation, and death.
Redundant role for early growth response transcriptional regulators in thymocyte differentiation and survival.
No sample metadata fields
View SamplesTo elucidate effects of tumor host interactions in vivo in CLL, purified tumor cells were obtained concurrently from blood, bone marrow and/or lymph node and analyzed by gene expression profiling.
The lymph node microenvironment promotes B-cell receptor signaling, NF-kappaB activation, and tumor proliferation in chronic lymphocytic leukemia.
Specimen part, Subject
View SamplesGene expression analysis of different B-cell chronic lymphoproliferative disorders
Improved classification of leukemic B-cell lymphoproliferative disorders using a transcriptional and genetic classifier.
Specimen part
View SamplesIn most embryos, the mid-blastula transition is a complex process featuring maternal RNA degradation, cell cycle pause, zygotic transcriptional activation and morphological changes. The nucleocytoplasmic (N/C) ratio has been proposed to control the multiple events at MBT. To understand the global transcriptional response to the changes of the N/C ratio, we profiled wild type and haploid embryos using cDNA microarrays at three developmental stages.
Coupling of zygotic transcription to mitotic control at the Drosophila mid-blastula transition.
No sample metadata fields
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