Project description:Tropolones are small organic compounds with metal-directing moieties. Functionally, tropolones inhibit the proliferation of cancer cell lines, possibly through the inhibition of metalloenzymes such as select histone deacetylases (HDACS). Pan-HDAC inhibitors are therapeutically beneficial in the treatment of multiple myeloma albeit with significant side-effects likely owning to their lack of specificity. It was therefore hypothesized that tropolones might have anti-myeloma activities. To this end, a series of novel a-substituted tropolones were evaluated for cytotoxic effects in multiple myeloma cells. While all tested tropolones showed some level of toxicity, MO-OH-Nap had consistently low EC50 values between 1-11 mM in all three cell lines tested and was used for subsequent experiments. MO-OH-Nap was found to induce apoptosis in a concentration-dependent manner. Time course experiments demonstrated that MO-OH-Nap promotes caspase cleavage in a time-frame that was distinct from the pan-HDAC inhibitor SAHA. Furthermore, MO-OH-Nap- and SAHA-treated cells possess unique gene expression patterns, suggesting they promote apoptosis via different mechanisms. In particular, MO-OH-Nap increases the expression of markers associated with endoplasmic reticulum stress and the unfolded protein response. Synergistic cytotoxic effects were observed when cells were treated with the combination of MO-OH-Nap and the proteasome inhibitor bortezomib. However, treatment with MO-OH-Nap did not abrogate the bortezomib-induced increase in aggresomes, consistent with an HDAC6-independent mechanism for the observed synergy. Collectively, these finding support further investigation into the usefulness of a-substituted tropolones as anti-myeloma agents.
Project description:Gene expression (GE) profiling of multiple myeloma (MM) cells is a promising means of identifying high-risk MM patients. The analyses depend on plasma cell purification by CD138+ cell separation. Considering the sensitivity of gene transcription, we wanted to test if cell separation distorts true in vivo GE patterns. We performed a controlled study of running 4 human myeloma cell lines (HMCLs: U266, INA-6, RPMI 8226, and NCI H929) through a CD138+ separation procedure identical to the handling of clinical samples. We then compared the resulting effects on gene expression. Using U266 as a screening model, we performed global GE analysis using the Affymetrix Human Gene 1.0 ST array. Sample cells showed significant changes (adj. p<0,05) in 670 genes compared to the non-separated controls. We searched for upregulated genes of myeloma and/or cancer relevance and chose (in decending fold change order) FOS, DUSP1, MIRN21, NFKBIA, and ATF4 for PCR validation. Note: Only U266 cells were used for microarray analysis. The other cell lines were used later to validate the array results.
Project description:To identify epigenetically silenced genes in multiple myeloma (MM) cell lines and to determine the effects of 5-aza-2-deoxycytidine and trichostatin A on gene expression. We treated 3 multiple myeloma cell lines (MM1, NCI-H929, U266) with 5-aza-2-deoxycytidine and/or trichostatin A.
Project description:We used microarrays to examine changes in gene expression in multiple myeloma cell lines following treatment with arsenic trioxide and darinaparsin Experiment Overall Design: Four multiple myeloma cell lines (U266, MM.1s, KMS11, 8226/S) were treated with either arsenic trioxide (ATO) for 6, 24, or 48 hours or darinaparsin (DAR) for 6 or 24 hours; RNA was extracted from treated and control cells for microarray analysis
Project description:In multiple myeloma (MM), abnormal plasma cells interact with bone marrow (BM) stromal cells and vascular cells among others. A part of the BM milieu is considered highly hypoxic, and myeloma cells in situ may be influenced by circumstances other than normoxia in vitro. Hence, we attempted to confirm the role of hypoxic MM-derived exosomes in the BM milieu. We established a novel hypoxia-resistant cell line, U266HR, derived from U266 cells cultured for >4 months under hypoxia (1% O2), as a model of MM cells localizing in an extensively hypoxic milieu. We used U266 cells and U266HR cells, as donor cells, and HUVECs as recipient cells. Exosomes derived from U266 cells (normoxia or hypoxia) and exosomes derived from U266HR cells (hypoxia-resistant sub-line) were used for validation of angiogeneic activity, such as tube formation assay. Exosomes derived from the U266HR cells significantly increased tube formation of HUVECs than those from U266 cells. To identify intercellular and exosomal miRNAs specifically expressed in hypoxia-resistant cells, we assess the expression profiles of intercellular and extracellular miRNAs in U266 cells and U266HR cells using Taqman MicroRNA Array v2.0 (Applied Biosystems, Bedford, MA).
Project description:Bortezomib therapy has been proven successful for the treatment of relapsed and/or refractory multiple myeloma (MM). However, both intrinsic and acquired resistance has already been observed. In this study, we explored the relationship between CD9 expression and bortezomib sensitivity in MM Both intrinsic and acquired resistance has already been observed. In this study, we explored the relationship between CD9 expression and bortezomib sensitivity in MM. We found that down-regulation of CD9 by methylation decreased bortezomib sensitivity in multiple myeloma. A six chip study using total RNA recovered from three separate wild-type cultures of U266 cells and three separate cultures of U266 with CD9 overexpression. Each chip measures the expression level of 45,033 genes from Homo sapiens with fourteen 60-mer probe pairs (PM/MM) per gene, with three-fold technical redundancy.
Project description:Here we report the use of high-throughput sequencing technologies (RNA-seq, ATAC-seq, ChIP-seq) to identify the molecular programme of the transcirption factor c-MAF (MAF) in parental (MM1.S, JJN3, H929), MAF-depleted (MM1S, JJN3) and MAF-overexpressing (MM1S, U266) multiple myeloma (MM) cells . We performed chromatin immunoprecipitation followed by sequencing (ChIP-seq) against MAF in naive MM cells , and against MAF, H3K27ac and H3K4me1 in MAF-overexpressing cells. Assay for Transposase-Accessible Chromatin with high-throughput sequencing (ATAC-seq) was performed on MAF-overexpressing U266 myeloma cells. In addition, we identifed the transcriptome of MAF-depleted myeloma cells 3 days after lentiviral transduction with MAF-targeting shRNA and scbl control. Our integrated -omics approach provides a comprehensive characterization of the role and function of MAF in myeloma cells and provides novel insights towards the discovery and design of molecular targets for precision therapy against MAF-overexpressing MM.
Project description:Genome-wide analysis of gene expression in response to bortezomib treatment (33 nM) in cell lines before and after selection for resistance. Multiple myeloma (MM) is a hematologic malignancy characterized by the proliferation of neoplastic plasma cells in the bone marrow. While the first-to-market proteasome inhibitor bortezomib/VELCADE has been successfully used to treat myeloma patients, drug resistance remains an emerging problem. In this part of the study, we identify signatures of bortezomib sensitivity by gene expression profiling (GEP) using The human myeloma cell lines MM1.S and U266 (obtained from ATCC). Finally, these data reveal complex heterogeneity within MM and suggest resistance to one drug class reprograms resistant clones to make them more sensitive to a distinct class of drugs. This study represents an important next step in translating pharmacogenomic profiling and may be useful for understanding personalized pharmacotherapy of MM patients. Transcript profiling timecourses after treatment with Bortezomib treatment (33nm) in two myeloma cell lines.
Project description:Here we report the use of high-throughput sequencing technologies (RNA-seq, ChIP-seq) to identify the molecular programme of PBX1 and FOXM1 in multiple myeloma cells (MM1S, U266 cell lines). We performed Chromatin Immunoprecipitation followed by sequencing (ChIP-seq) against PBX1 in MM1S and U266 cells (n=2). In addition, we identifed the transcriptome of PBX1-depleted and FOXM1-depleted myeloma cells 3 days after transduction with shRNA-expressing lentiviral vectors. Molecular characterization revealed PBX1 as a novel epigenetic regulator of myeloma cell survival and proliferation. PBX1 directly and unilaterally controls the FOXM1 transcriptional programme and, together,they regulate the high-risk transcriptional signature of chr1q-amplified cells. Pharmacological inhibition of the unified PBX1-FOXM1 axis with thiostrepton showed selectivity against chr1q-amplified MM. Altogether, these data reveal PBX1-FOXM1 axis as a novel therapeutic avenue against chr1q-amplified MM.
Project description:Purpose: We examined how transcriptional state changes relate to clonal selection as BRAF inhibitor resistance develops in BRAF-mutated myeloma. Methods: To this end we generated three single-cell clones from U266, a BRAFK601N -mutated myeloma cell line and DP6- a BRAFV600E myeloma cell line. All three U266 and DP6 clones were subjected to long-term dabrafenib treatment at their established IC50 doses (U266: 10uM, DP6 1nM). Bulk RNA-seq was performed before treatment, day 7, day 14, day 42 and at time of resistance. Results: Transcriptional adaptation after seven days was homogeneous for all clones, but was different across both cell lines. Oxidative phosphorylation (OxPhos) emerged as the most consistently enriched signaling pathway in persistent cells from both cell lines as compared to baseline. Conclusions: BRAF inhibition in BRAF-mutated myeloma cells leads to transcriptional reprogramming with induction of OxPhos-related genes within a brief period of time.