Previous study demonstrated that HDAC3 has a critical role in MM proliferation; however, the underlying mechanism has not yet been elucidated. We identify that HDAC3 inhibition targets DNMT1 through dual regulations. We demonstrate that knockdown of DNMT1 leads to apoptosis and significant growth inhibition in myeloma cells. HDAC3 inhibition by gene silencing or HDAC3 selective inhibitor BG45 downregulates an oncoprotein c-Myc through its acetylation. c-Myc directly regulates DNMT1 expression at its enhancer region. Furthermore, HDAC3 directly regulates the stability of DNMT1 protein through its acetylation. Pharmaceutical inhibition of HDAC3 and DNMT1 synergistically induce MM growth inhibition in in vitro and in vivo settings.
HDAC3 regulates DNMT1 expression in multiple myeloma: therapeutic implications.
Cell line
View SamplesTargeting protein kinase C (PKC) isoforms by the small molecule inhibitor enzastaurin has shown promising pre-clinical activity in a wide range of tumor cells. In this study, we further delineated its mechanism of action in multiple myeloma (MM) cells and found a novel role of b-catenin in regulating growth and survival of tumor cells. Specifically, inhibition of PKC leads to rapid accumulation of b-catenin by preventing the phosphorylation required for its proteasomal degradation. Microarray analysis and siRNA-mediated gene silencing in MM cells revealed that accumulated b-catenin activates early ER stress signaling via eIF2a, CHOP and p21, leading to immediate growth inhibition. Furthermore, accumulated b-catenin contributes to enzastaurin-induced cell death. Both sequential knock-down of b-catenin, c-Jun, and p73, as well as overexpression of b-catenin or p73 confirmed that accumulated b-catenin triggers c-Jun-dependent induction of p73, thereby conferring MM cell apoptosis. In summary, our data reveal a novel role of b-catenin in ER stress-mediated growth inhibition, and a new pro-apoptotic mechanism triggered by b-catenin upon inhibition of PKC isoforms. Moreover, we identify p73 as a potential novel therapeutic target in MM. Based on these and previous data, enzastaurin is currently under clinical investigation in a variety of hematologic malignancies including MM.
Targeting PKC: a novel role for beta-catenin in ER stress and apoptotic signaling.
No sample metadata fields
View SamplesMM1.S cells stably transduced with control or b-catenin shRNA were established. Total RNA was isolated from 5x 10^6 cells of each in triplicate.
Aurora kinase A is a target of Wnt/beta-catenin involved in multiple myeloma disease progression.
Cell line
View SamplesWe used microarrays to detail the global programme of gene expression underlying CS1-regulated biological processes including increased cell adhesion and cell proliferation.
CS1 promotes multiple myeloma cell adhesion, clonogenic growth, and tumorigenicity via c-maf-mediated interactions with bone marrow stromal cells.
No sample metadata fields
View SamplesMelphalan-induced modulation of miR-221/222 levels in MM cells. Melphalan-resistant U266/LR7 cells showed the highest induction of miR-221/222 after drug exposure. To study the transcriptome perturbation induced in MM cells following the combination of miR-221/222 inhibitors plus melphalan we used the whole gene expression data
A 13 mer LNA-i-miR-221 Inhibitor Restores Drug Sensitivity in Melphalan-Refractory Multiple Myeloma Cells.
Cell line, Treatment
View SamplesMultiple Myeloma (MM) remains incurable despite novel therapies, suggesting the need for further identification of factors mediating tumorigenesis and drug resistance. We performed microarray analysis to identify the molecular mechanisms whereby pDCs confer growth and drug resistance in MM cells.
Functional interaction of plasmacytoid dendritic cells with multiple myeloma cells: a therapeutic target.
Cell line
View SamplesTo identify factors involved in glioma-initiating cells (GICs), we compared gene expressions between GIC-like cells and non-GICs.
Combination of a ptgs2 inhibitor and an epidermal growth factor receptor-signaling inhibitor prevents tumorigenesis of oligodendrocyte lineage-derived glioma-initiating cells.
Specimen part
View SamplesInducible co-stimulator (ICOS) interaction with its ligand (ICOSL) is involved in several T cell effector functions. While blockade of ICOS:ICOSL interaction in chronic graft versus host disease (GVHD) seems benefi cial, results for acute GVHD remain controversial. To further elucidate its role in acute GVHD, C57BL / 6 mice were lethally irradiated and reconstituted with allogeneic spleen cells in the absence or presence of ICOSL-blocking mAb. Mice reconstituted with allogeneic spleen cells experienced severe GVHD and died untreated within 6 9 days after transplantation. Mice treated with an anti-ICOSL mAb starting from day 3 after transplantation gained weight again and survived for at least additional 12 days, although the treatment was already stopped at day 11 after transplantation. In contrast, the anti-ICOSL treatment starting from day 0 did not prevent GVHD. The diff erence between therapeutic (day 3) and prophylactic (day 0) anti-ICOSL treatment was independent of CD25 + CD4 + regulatory T cells since their depletion did not abrogate the therapeutic eff ect of ICOSL blockade. Microarray analysis revealed IFN- and chemokine up-regulation in spleen cells of prophylactically treated mice, emphasizing kinetic dependence of acute GVHD modulation via blockade of ICOS:ICOSL interaction.
Only therapeutic ICOS:ICOSL blockade alleviates acute graft versus host disease.
Sex, Specimen part
View SamplesTo identify factors involved in glioma-initiating cells (GICs), we compared gene expression between GIC-like cells and non-GICs.
Sox11 prevents tumorigenesis of glioma-initiating cells by inducing neuronal differentiation.
Specimen part
View SamplesTo identify factors involved in tumorigenicity of glioma-initiating cells (GICs), we compared gene expression in GIC-like cells with and without sox11 expression.
Sox11 prevents tumorigenesis of glioma-initiating cells by inducing neuronal differentiation.
Specimen part, Cell line
View Samples