Comprehensive Analysis of Homeobox Gene Expression in Hodgkin Lymphoma Cell Lines Reveals Similarities to Prostate Carcinoma.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 966-966
Author(s):  
Stefan Nagel ◽  
Christof Burek ◽  
Hilmar Quentmeier ◽  
Corinna Meyer ◽  
Andreas Rosenwald ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Cycle ◽  
B Cell ◽  
Hodgkin Lymphoma ◽  
Cell Lines ◽  
Prostate Carcinoma ◽  
Homeobox Genes ◽  
Homeobox Gene ◽  
Cell Cycle Regulators ◽  
Rt Pcr

Abstract Homeobox genes code for transcription factors with essential regulatory impact on cellular processes during embryogenesis and in the adult. Increasingly, members of the circa 200 gene strong family are emerging as major oncogenic players, prompting our investigation into possible homeobox gene dysregulation in Hodgkin lymphoma (HL) in which no recurrent oncogene involvement has been known. Accordingly, we screened 6 well characterized HL cell lines (HDLM-2, KM-H2, L-1236, L-428, L-540, SUP-HD1) and 3 non-Hodgkin lymphoma (NHL) cell lines (RC-K8, RI-1, SC-1) for homeobox gene expression using Affymetrix U133-2.0 whole-genome oligonucleotide microarrays. Of 15 candidate genes thus shown to reveal HL-specific expression patterns, 5 homeobox genes were shortlisted as potentially key dysregulatory targets in HL after additional RT-PCR expression analysis relative to controls. While 3/5 homeobox genes were upregulated in HL (HOXB9, HOXC8, HLXB9), 2/5 were downregulated (BOB1, PAX5). Furthermore, cloning and sequencing RT-PCR products obtained with degenerate primers recognizing conserved homeobox motifs confirmed the predominant expression of HOXB9 in HL cells. However, fluorescence in situ hybridization (FISH) analysis of the HOXB locus (at 17q21) revealed no cytogenetic aberrations, indicating that its activation is conducted non-chromosomally in HL cells. Surprisingly, known target genes of HOXB9 and HOXC8 remained unperturbed, implying novel downstream effector pathways in HL cells. Antisense oligos directed against HOXB9 and forced expression experiments using cloned full length HOXB9 cDNA indicated its involvement in both proliferation and apoptosis. Cell cycle regulators BTG1, BTG2 and GEMININ have been described to interact with HOXB9 and may represent potential targets deserving investigation. We recently showed that HLXB9 promotes IL6 expression in HL cells in response to a constitutively active PI3K signalling pathway therein (Nagel et al., Leukemia19, 841–6, 2005). Our most recent data indicate that HLXB9 is also expressed in various NHL cell lines including anaplastic, diffuse and mediastinal large cell as well as follicular B-cell lymphomas while expression is notably absent from Burkitt, mantle cell and natural killer T-cell lymphomas reflecting their pathologic classification. Intriguingly, our data highlight unexpected similarities between HL and prostate cancer cells which together uniquely overexpress HOXB9, HOXC8 and HLXB9 (or its close homolog GBX2). Additional genes expressed in prostate carcinoma (HOXB13, PRAC1, PRAC2) were detected in two HL cell lines (KM-H2 and L-428) suggesting further parallels may be revealed. Detection of downregulated B-cell differentiation factors BOB1 and PAX5 in our panel of HL cell lines validated this approach. Both factors were previously implicated in oncogenesis of HL lacking IGH rearrangements and other key B-cell characteristics. In summary, we identified a unique homeobox gene expression pattern involving HOXB9, HOXB13, HOXC8 and HLXB9 in HL cell lines resembling that of prostate carcinoma cells. Overexpressed HOXB9 contributes to proliferation and protects against apoptosis in HL cells potentially via interacting with cell cycle regulators BTG1/2 and/or GEMININ.

Repression of Mir-106b Family Members Does Not Alter Cell Cycle Progression in Hodgkin Lymphoma

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 4722-4722
Author(s):  
Johan H Gibcus ◽  
Lu Ping Tan ◽  
Rikst Nynke Schakel ◽  
Geert Harms ◽  
Peter Moeller ◽  
...  
Keyword(s):  
Cell Cycle ◽  
B Cell ◽  
Cell Cycle Arrest ◽  
Hodgkin Lymphoma ◽  
Cell Lines ◽  
Target Genes ◽  
Family Members ◽  
Luciferase Reporter ◽  
P21 Protein ◽  
Cycle Arrest

Abstract MicroRNAs (miRNAs) are 19–25 nucleotide long RNA molecules derived from precursor genes that inhibit the expression of target genes by binding to their 3′ UTR region. Expression of miRNAs is often tissue specific and miRNA profiling has shown specific miRNA expression patterns in both B-cell development and lymphomagenesis. Hodgkin lymphoma is derived from pre-apoptotic germinal center B-cells, although a general loss of B cell phenotype is noted. Using quantitative RT-PCR and miRNA microarray, we determined the miRNA profile of HL and compared this with the profile of a panel of B-cell non-Hodgkin lymphomas (NHL). The two methods showed a very good correlation for the expression levels of the individual miRNAs. Using a large panel of cell lines, we confirmed differential expression between HL and other B-cell lymphoma derived cell lines for 27 miRNAs. The HL specific miRNAs included miR-155, miR-21 and miR-106b seed family members miR-17-5p, miR-20a, miR-93, miR-106a and miR- 106b. Next, we performed target gene validation of predicted target genes for miR-17-5p, which is highly expressed in HL. Using luciferase reporter assays with stabilized anti-sense miR17-5p oligonucleotides, we showed that GPR137B, RAB12 and RBJ are likely miR-17-5p target genes in two different HL cell lines. Previous publications indicated that miR-106b seed family members negatively regulate the cyclin-dependent kinase inhibitor 1A (p21/CIP1) resulting in cell cycle arrest at G1. Consistent with these findings, we show that the miR-106b family members are highly expressed in L428, whereas p21 is not. However, inhibition of the miR-106b seed family members in L428 does not result in elevated p21 protein expression. Furthermore, there is no cell cycle arrest, growth reduction or increase in cell death and apoptosis after inhibition of the miR-106b seed family members. Thus, we conclude that blocking of the miR-106b seed family members does not necessarily lead to indiction of p21 protein. This suggests an additional regulatory layer of p21 expression in L428 cells.

Contribution of Deregulated miRNAs to the Phenotypic Characteristic of Hodgkin Lymphoma.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 265-265
Author(s):  
Lu Ping Tan ◽  
Bart-Jan Kroesen ◽  
Enrico Tiacci ◽  
Gerben Duns ◽  
Erwin Seinen ◽  
...  
Keyword(s):  
Cell Cycle ◽  
B Cells ◽  
B Cell ◽  
Hodgkin Lymphoma ◽  
Cell Lines ◽  
Mirna Expression ◽  
Conflicts Of Interest ◽  
System Development ◽  
Cell Phenotype ◽  
Immune System Development

Abstract Abstract 265 In Hodgkin Lymphoma (HL), the Hodgkin Reed-Sternberg (HRS) cells are a minority of large mono- or multi-nucleated B cells characterized by a loss of B cell phenotype, constitutive NF-kB activation, a disturbed cell cycle and anti-apoptotic features. In this study we investigated the role of deregulated miRNA expression in the pathogenesis of HL. MiRNA in situ hybridization (ISH) in HL tissue was performed to determine expression of miRNAs previously reported to be highly abundant in HL cell lines, in HRS cells. Next we identified the miRNA-targetome of two HL cell lines by immunoprecipitation of RISC in untransfected and transfected cell lines. miRNA ISH confirmed expression of miR-17-5p, miR-24, miR-106a, miR-146a, miR-150, miR-155, miR-181b and miR-210 in HRS cells. Ago2-immunoprecipitation followed by microarray analysis of the co-immunoprecipitated mRNA revealed that the miRNA-targetome of HL comprises of about 2,500 genes. Inhibition of the anti-miR-17 seed family revealed that about 500 of these genes are regulated by miRNAs of the miR-17 seed family. Gene ontology (GO) analysis for the total miRNA-targetome of HL showed a significant enrichment of genes involved in the regulation of cell cycle, apoptosis, immune system development and NF-kB cascade. The miRNA-targetome of HL contained several genes known to be mutated in HRS cells, including A20, FAS, NFKB1A, NFKB1E, PERP and SOCS1. Also, using previously reported gene expression data, we defined a set of genes downregulated in HL cell lines (L428 and L1236) compared to germinal center B cells (GCB) and compared them to the miRNA-targetome of the same cell lines. This resulted in the identification of 149 genes in L428 and 183 genes in L1236 that were subjected to miRNA mediated repression. Unexpectedly, only a few of all the reported inactivated genes in HRS cells that might contribute to loss of B cell phenotype (MYBL1 and CXCR4) were found to be regulated by miRNAs in HL. In conclusion, we confirmed the expression of miRNAs in the HRS cells of HL tissue and identified miRNA repressed genes in HL. Our data indicated that aberrant miRNA expression contributes to the deregulation of apoptosis, cell cycle, and NF-kB pathways but not loss of B cell phenotype in HL. Disclosures: No relevant conflicts of interest to declare.

New Pathogenetic Insights Into Classical Hodgkin Lymphoma Revealed by Gene Expression Profiling of Microdissected Hodgkin/Reed-Sternberg Cells.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 266-266 ◽  
Author(s):  
Enrico Tiacci ◽  
Verena Brune ◽  
Susan Eckerle ◽  
Wolfram Klapper ◽  
Ines Pfeil ◽  
...  
Keyword(s):  
Gene Expression ◽  
B Cells ◽  
B Cell ◽  
Gene Expression Profiling ◽  
Hodgkin Lymphoma ◽  
Cell Lines ◽  
Expression Profiling ◽  
Expression Profiles ◽  
B Cell Lymphoma ◽  
Cell Phenotype

Abstract Abstract 266 Background. Previous gene expression profiling studies on cHL have been performed on whole tissue sections (mainly reflecting the prominent reactive background in which the few HRS cells are embedded), or on cHL cell lines. However, cultured HRS cells do not likely reflect primary HRS cells in all aspects, being derived from end-stage patients and from sites (e.g. pleural effusions or bone marrow) which are not typically involved by cHL and where HRS cells lost their dependence on the inflammatory microenvironment of the lymph node. Methods. ∼1000–2000 neoplastic cells were laser-microdissected from hematoxylin/eosin-stained frozen sections of lymph nodes taken at disease onset from patients with cHL (n=16) or with various B-cell lymphomas (n=35), including primary mediastinal B-cell lymphoma (PMBL) and nodular lymphocyte-predominant Hodgkin lymphoma (nLPHL). After two rounds of in vitro linear amplification, mRNA was hybridized to Affymetrix HG-U133 Plus 2.0 chips. Expression profiles were likewise generated from sorted cHL cell lines and several normal mature B-cell populations. Results. Primary and cultured HRS cells, although sharing hallmark cHL signatures such as high NF-kB transcriptional activity and lost B-cell identity, showed considerable transcriptional divergence in chemokine/chemokine receptor activity, extracellular matrix remodeling and cell adhesion (all enriched in primary HRS cells), as well as in proliferation (enriched in cultured HRS cells). Unsupervised and supervised analyses indicated that microdissected HRS cells of cHL represent a transcriptionally unique lymphoma entity, overall closer to nLPHL than to PMBL but with differential behavior of the cHL histological subtypes, being HRS cells of the lymphocyte-rich and mixed-cellularity subtypes close to nLPHL cells while HRS cells of NS and LD exhibited greater similarity to PMBL cells. HRS cells downregulated a large number of genes involved in cell cycle checkpoints and in the maintenance of genomic integrity and chromosomal stability, while upregulating gene and gene signatures involved in various oncogenic signaling pathways and in cell phenotype reprogramming. Comparisons with normal B cells highlighted the lack of consistent transcriptional similarity of HRS cells to bulk germinal center (GC) B cells or plasma cells and, interestingly, a more pronounced resemblance to CD30+ GC B cells and CD30+ extrafollicular B cells, two previously uncharacterized subsets that are transcriptionally distinct from the other mature B-cell types. Conclusions. Gene expression profiling of primary HRS cells provided several new insights into the biology and pathogenesis of cHL, its relatedness to other lymphomas and normal B cells, and its enigmatic phenotype. Disclosures: No relevant conflicts of interest to declare.

The Brd-Inhibitor OTX015 Is Active in Pre-Clinical Models of Mature B-Cell Lymphoid Tumors

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 1657-1657 ◽  
Author(s):  
Paola Bonetti ◽  
Michela Boi ◽  
Maurilio Ponzoni ◽  
Maria Grazia Tibiletti ◽  
Anastasios Stahis ◽  
...  
Keyword(s):  
Cell Cycle ◽  
B Cell ◽  
Cell Lines ◽  
Proliferative Activity ◽  
Research Funding ◽  
Cell Lymphoma ◽  
Rt Pcr ◽  
Down Regulation ◽  
Myc Gene ◽  
Dose Dependent

Abstract Abstract 1657 Background: Bromodomain-containing proteins play an important role in gene expression regulation, via chromatin structure remodelling. Antitumor activity has been reported in acute and chronic hematological malignancies using inhibitors of BRD2/3/4, members of the Bromodomain and Extraterminal (BET) family. Here, we report anti-proliferative activity of OTX015, a novel selective orally bioavailable BRD2/3/4 inhibitor, in a large panel of cell lines derived from mature B-cell lymphoid tumors. Material and Methods: Established human cell lines derived from 13 diffuse large B-cell lymphoma (DLBCL), 4 mantle cell lymphoma (MCL), three splenic marginal zone lymphoma (SMZL) and from three multiple myeloma (MM) were treated with increasing doses of OTX015 (OncoEthix SA) and MTT assays were performed after 72 hours exposure. For cell cycle analysis, cells were treated and stained with Click-iT Edu Flow Cytometry Assay Kits (Invitrogen) and 7-AAD and analyzed for DNA content using a FACScan flow cytometer. Results were analyzed with FlowJo 7.6.3 software. RNA extracted using the Qiagen RNAEasy kit and reverse-transcribed using the Superscript First-Strand Synthesis System for RT-PCR kit according to the manufacturer's instructions. RT-PCR was performed using Fast SYBR Green Master Mix on a StepOnePlus Real-Time PCR System. For senescence detection, cells were stained using a b-Galactosidase Staining Kit (Calbiochem). Results: OTX015 demonstrated anti-proliferative activity in DLBCL cell lines (median IC50 0.192μM; range 0.069–12.68μM). Similar results were obtained on SMZL (median IC50 0.165μM, range 0.105–0.24μM), and on MM cell lines (median IC50 0.449μM; range 0.06–0.7μM). Conversely, MCL cell lines appeared less sensitive to OTX015 (median IC50 2.01μM; range 1.22- >15μM). Among DLBCL cell lines, there was no significant difference based upon the cell of origin of the cell lines. OTX105 caused a cell cycle arrest in G1 in a dose-dependent manner in 5/5 DLBCL and 3/3 MM cell lines, without an increase in cell death. An increase in the percentage of senescent cells after treatment with the BRD-inhibitor was observed in 1/1 sensitive DLBCL cell line. In order to understand the mechanism of action of OTX015, we assessed MYC mRNA levels before and after 24h treatment with increasing doses. We observed a dose-dependent suppression of MYC mRNA by OTX015 in 4/5 DLBCL and in 2/2 MM cell lines. In DLBCL, down-regulation of MYC mRNA was observed within 1h after treatment with OTX015, suggesting a direct effect of the compound on the MYC gene. To determine whether the suppression of MYC gene by OTX015 was reversible, DLBCL cell lines were treated for 2h with OTX015 and then the inhibitor was removed from the media. MYC mRNA suppression appeared reversible, as shown in DLBCL cell lines, which, after 2h exposure to OTX015, showed a time-dependent restoration of MYC mRNA expression to untreated levels after 2–3h. In one of the most sensitive DLBCL cell lines no MYC mRNA down-regulation was observed after treatment, suggesting that alternative pathways can be affected by BRD-inhibition. Conclusion: OTX015 is a new potent BRD-inhibitor with evident anti-proliferative activity in several cell lines representative of mature B-cell tumors. An apparently reversible down-regulation of MYC mRNA was commonly observed, appearing as a possible mechanism of action of the compound. The compound appears worth of further investigation as a new promising therapeutic agent in mature B-cell origin malignancies. A phase I trial is scheduled to start in 2012. Disclosures: Bonetti: OncoEthix SA: Research Funding. Inghirami:OncoEthix SA: Research Funding. Noel:OncoEthix SA: Membership on an entity's Board of Directors or advisory committees. Bertoni:OncoEthix SA: Research Funding.

scholarly journals Genomic and Expression Profiling of Hairy Cell Leukemia Revealed Multiple Mechanisms of NFkB Activation

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 3526-3526 ◽  
Author(s):  
Stefan Nagel ◽  
Stefan Ehrentraut ◽  
Corinna Meyer ◽  
Maren Kaufmann ◽  
Hans G Drexler ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Cycle ◽  
B Cell ◽  
Cell Lines ◽  
Expression Profiling ◽  
Braf V600e ◽  
Hairy Cell ◽  
Cell Leukemia ◽  
Braf Mutations ◽  
Nfkb Pathway

Abstract Hairy cell leukemia (HCL) is a rare chronic B-cell lymphoproliferative disorder where the malignant B-cells manifest a “hairy” appearance under the microscope. Recent studies have identified BRAF V600E mutations in most HCL patients, highlighting this abnormality as a molecular hallmark for this disease. However, mutated BRAF occurs widely – already described in several solid tumors, including melanoma, thyroid and colorectal carcinomas, indicating that BRAF V600E is not pathognomonic in HCL. Cell lines originating from HCL patients lack BRAF mutations but retain the typical piliferous morphology and the appropriate HCL immunophenotype (CD19, CD11c, CD103, CD25, CD123), thus constituting tools for identifying alternative mechanisms of leukemogenesis in this disease entity. Genomic aberrations in hematopoietic tumors recurrently target loci bearing genes involved in malignant transformation. These genes may include both candidate biomarkers and potential therapeutic targets. To identify such genes in HCL we here combined genomic profiling and gene expression quantification of a well characterized HCL cell line containing several chromosomal aberrations. The expression levels of genomically targeted genes were compared to HCL control cell lines, identifying 91 deregulated genes. Gene set enrichment analysis of which indicated apoptosis, cell cycle regulation and DNA damage response (DDR) as altered processes in HCL. Accordingly, REL (NFkB and apoptosis), CDK6 and BRAF (cell cycle), ATM and CUTL1 (DDR) comprised prominent target genes overexpressed in this cell line. The same genes were found to be conspicuously expressed in HCL patient samples in silico (Fernandez et al., 2010; Gene Expression Omnibus GSE16455), supporting their clinical significance. Treatments of HCL cell lines for particular siRNA-mediated gene knockdowns and with selective pharmacological inhibitors helped to reveal a regulatory network highlighting NFkB at a central position. Consistently, focused analysis of expression profiling data of several cell lines supported elevated NFkB-pathway activity in HCL and ABC-DLBCL when compared to GC-DLBCL. In conclusion, we identified deregulated genes and multiple mechanisms which contribute to aberrantly activated NFkB-pathway in HCL. Therefore, NFkB may represent a B-cell specific hallmark of HCL and a promising novel therapeutic target most notably in patients lacking BRAF mutations in this entity. Disclosures No relevant conflicts of interest to declare.

Bifunctional siRNA Design Targeting Non-Hodgkin’s Lymphoma.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 2357-2357
Author(s):  
Britta Höhn ◽  
Harris S. Soifer ◽  
Stephen J. Forman ◽  
John J. Rossi
Keyword(s):  
Gene Expression ◽  
Transcription Factors ◽  
B Cell ◽  
Cell Lines ◽  
B Cell Lymphoma ◽  
Lymphoma Cell ◽  
Interferon Response ◽  
Rt Pcr ◽  
Sirna Duplex ◽  
Hodgkin's Lymphomas

Abstract Non-Hodgkin’s lymphomas comprise a group of heterogeneous lymphoid malignancies that represent the fifth most common form of cancer in the United States. A hallmark of many types of B-cell lymphomas is the constitutive expression of oncogenes such as the transcription factors Bcl-6, STAT3 and c-Myc and the anti-apoptotic protein Bcl-2. Over expression of these genes causes uncontrolled proliferation and survival of malignant cells, making knockdown of these genes by RNA interference (RNAi) a rational strategy for therapeutic intervention. RNAi is a conserved endogenous mechanism in which small interfering RNAs (siRNAs) suppress target-specific gene expression by promoting mRNA degradation. We have designed potent Dicer-substrate siRNAs using different computer algorithms to predict accessible target sites in the mRNAs of B-cell lymphoma oncogene targets. The Dicer-substrate 27mers are designed asymmetrically, so that Dicer processing yields a predicted 21mer siRNA duplex for entry into RNA induced silencing complex (RISC). Dicer-substrate siRNAs show improved efficacy at lower concentrations compared with conventional 21mer siRNAs, suggesting the reduction of potential off-target effects. In addition, we have designed bifunctional siRNA duplexes that contain two fully target-complimentary antisense strands against two different target mRNAs, but that are only partially complementary to each other. In vitro cleavage assays indicate that our bifunctional siRNAs have sufficient complementarity to form stable duplexes and can be processed into smaller molecules by recombinant Dicer. When delivered to the Burkitt’s lymphoma cell line Raji by electroporation, the most effective siRNAs reduced target mRNA levels by ∼80% as determined by quantitative RT-PCR and immunoblot analysis. Silencing of transcription factors affected the expression of downstream target genes, indicating a relevant effect on growth on survival of lymphoma cells through oncogene down regulation by RNAi. One concern with RNAi-mediated therapy is the possible recognition of siRNA duplex by cell’s own response to double-stranded RNA (dsRNA) that could trigger an unwanted interferon response. To determine whether our Dicer-substrate siRNAs cause an interferon response, we monitored induction of the cellular dsRNA pathway by measuring gene expression of p56, OAS1 and interferon by quantitative RT-PCR after transfection of siRNAs in different cell lines. None of the analyzed siRNAs show a significant increase in the expression of interferon pathway related genes indicating that our selected siRNAs are powerful silencers of gene expression without inducing an interferon response. In future studies, these new identified siRNAs will be incorporated in nanoparticles or attached to antibodies / aptamers for cell-specific delivery to lymphoma cell lines to evaluate their potential alone or in combination with chemotherapeutic drugs in therapy for lymphoma.

Prima-1Met Combined with Bortezomib Has Synergistic Anti-Myeloma Activity By Modulation of Apoptosis and Cell Cycle Regulating Genes

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 4213-4213
Author(s):  
Priya Khoral ◽  
Robert J Guo ◽  
Jahangir Abdi ◽  
Hong Chang
Keyword(s):  
Gene Expression ◽  
Cell Cycle ◽  
Western Blot ◽  
Real Time ◽  
Cell Lines ◽  
Blot Analysis ◽  
Drug Combination ◽  
Western Blot Analysis ◽  
Rt Pcr ◽  
Novel Therapeutic

Abstract INTRODUCTION Multiple Myeloma (MM) is a plasma-cell malignancy characterized by dismal prognosis and a high level of relapse, thus novel therapeutic approaches are needed. PRIMA-1Met is a novel small molecule showing anti-tumour activity and currently in clinical phase I-II trials. We recently demonstrated that PRIMA-1Met has potent anti-MM activity in vitro and in vivo. Bortezomib (BTZ) is a proteasome inhibitor that has been successfully used for treating some cases of relapsed MM. The aim of the current study is to determine whether PRIMA-1Met could be used in combination with BTZ to enhance the cytotoxic effects in myeloma cells. METHODS Using three different MM cell lines (LP1, U266 and 8226), we established dose response curves for both PRIMA-1Met and BTZ, and tested drug cytotoxicity using MTT assays. We then tested drug cytotoxicity of a range of concentrations of the drugs in combination. The Chou Talay method was used to determine whether or not the drug combinations were synergistic. A gene expression array was used to investigate the mechanism of the drug combination's effects. Total RNA was isolated from MM cell pellets, then synthesized cDNAs were applied to real time RT-PCR gene expression arrays containing 84 genes of interest. The genes selected were involved in apoptotic as well as cell growth and proliferation pathways. After normalization to 4 different housekeeping genes, fold changes in gene expression were analyzed in both drug treated and control samples using the 2-ΔΔCt algorithm. Western blot analysis was used to further investigate proteins of interest. RESULTS Cell viability of 8226, LP1 and U266 cells treated with individual concentrations of PRIMA-1Met (10uM) and BTZ (10nM) was on average 65%, 45% and 72.5%, respectively. However, combination of above doses reduced viability to 20% in 8226 and LP1, and to 40% in U266. The Chou Talay method identified this drug combination as synergistic in 2 out of the three tested cell lines, with Combination Index (CI) values of 0.72 in 8226 and 0.582 in U266. The gene expression analysis in real time RT-PCR indicated that the drug combination resulted in downregulation of genes involved in cell cycle and proliferation (CCND1, CDK4, CDK6, CDK2, IGFIR), genes from the Bcl-2 family of apoptosis regulation (Bcl-2, Bcl-XL, Mcl-1), as well as MDM2 from the p53 signalling pathway, and MYC, which is involved in both apoptosis and cell cycle progression. Western blot analysis revealed up-regulation of cleaved caspase-3 and -9, implying involvement of the intrinsic apoptotic pathway in the drug combination's activity. CONCLUSION Our results reveal that PRIMA-1Met synergistically enhances the anti-MM effect of BTZ, leading to a significantly higher level of MM cell death. Real time RT-PCR gene array analysis offers some insight into the mechanism of this combination's effect, implicating apoptotic, cell cycle and growth regulating genes. Our study provides framework for further evaluation of this drug combination as a novel therapeutic strategy in MM. Disclosures No relevant conflicts of interest to declare.

KLF4 is a tumor suppressor in B-cell non-Hodgkin lymphoma and in classic Hodgkin lymphoma

Blood ◽  
2010 ◽  
Vol 116 (9) ◽  
pp. 1469-1478 ◽  
Author(s):  
Hanfeng Guan ◽  
Linka Xie ◽  
Frank Leithäuser ◽  
Lucia Flossbach ◽  
Peter Möller ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Tumor Suppressor ◽  
B Cell ◽  
Hodgkin Lymphoma ◽  
Cell Lines ◽  
Burkitt Lymphoma ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
Lymphoma Cell ◽  
Classic Hodgkin Lymphoma

The transcription factor KLF4 may act both as an oncogene and a tumor suppressor in a tissue-depending manner. In T- and pre-B-cell lymphoma, KLF4 was found to act as tumor suppressor. We found the KLF4 promoter methylated in B-cell lymphoma cell lines and in primary cases of B-cell lymphomas, namely, follicular lymphoma, diffuse large B-cell lymphoma, Burkitt lymphoma, and in classic Hodgkin lymphoma (cHL) cases. Promoter hypermethylation was associated with silencing of KLF4 expression. Conditional overexpression of KLF4 in Burkitt lymphoma cell lines moderately retarded proliferation, via cell-cycle arrest in G0/G1. In the cHL cell lines, KLF4 induced massive cell death that could partially be inhibited with Z-VAD.fmk. A quantitative reverse-transcribed polymerase chain reaction array revealed KLF4 target genes, including the proapoptotic gene BAK1. Using an shRNA-mediated knock-down approach, we found that BAK1 is largely responsible for KLF4-induced apoptosis. In addition, we found that KLF4 negatively regulates CXCL10, CD86, and MSC/ABF-1 genes. These genes are specifically up-regulated in HRS cells of cHL and known to be involved in establishing the cHL phenotype. We conclude that epigenetic silencing of KLF4 in B-cell lymphomas and particularly in cHL may favor lymphoma survival by loosening cell-cycle control and protecting from apoptosis.

Loss of the B-lineage–specific gene expression program in Hodgkin and Reed-Sternberg cells of Hodgkin lymphoma

Blood ◽  
2003 ◽  
Vol 101 (4) ◽  
pp. 1505-1512 ◽  
Author(s):  
Ines Schwering ◽  
Andreas Bräuninger ◽  
Ulf Klein ◽  
Berit Jungnickel ◽  
Marianne Tinguely ◽  
...  
Keyword(s):  
Gene Expression ◽  
B Cells ◽  
B Cell ◽  
Hodgkin Lymphoma ◽  
Cell Lines ◽  
Expression Profiles ◽  
Specific Gene ◽  
Mrna Levels ◽  
Study Gene Expression ◽  
B Lineage

Hodgkin and Reed-Sternberg (HRS) cells represent the malignant cells in classical Hodgkin lymphoma (HL). Because their immunophenotype cannot be attributed to any normal cell of the hematopoietic lineage, the origin of HRS cells has been controversially discussed, but molecular studies established their derivation from germinal center B cells. In this study, gene expression profiles generated by serial analysis of gene expression (SAGE) and DNA chip microarrays from HL cell lines were compared with those of normal B-cell subsets, focusing here on the expression of B-lineage markers. This analysis revealed decreased mRNA levels for nearly all established B-lineage–specific genes. For 9 of these genes, lack of protein expression was histochemically confirmed. Down-regulation of genes affected multiple components of signaling pathways active in B cells, including B-cell receptor (BCR) signaling. Because several genes down-regulated in HRS cells are positively regulated by the transcriptional activator Pax-5, which is expressed in most HRS cells, we studied HL cell lines for mutations in the Pax-5gene. However, no mutations were found. We propose that the lost B-lineage identity in HRS cells may explain their survival without BCR expression and reflect a fundamental defect in maintaining the B-cell differentiation state in HRS cells, which is likely caused by a novel, yet unknown, pathogenic mechanism.

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