Leflunomide Inhibits Proliferation of Neoplastic B-Cell Lines and Induces Apoptosis in Primary CLL Cells.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2497-2497
Author(s):  
Andrew P. Mone ◽  
John C. Byrd
Keyword(s):  
B Cell ◽  
Cell Line ◽  
Cell Lines ◽  
Untreated Control ◽  
Cytotoxic Effect ◽  
De Novo ◽  
Antiproliferative Effect ◽  
Pyrimidine Synthesis ◽  
De Novo Pyrimidine Synthesis

Abstract Leflunomide is a commercially available immunosuppressive agent approved for the treatment of rheumatoid arthritis. The compound is administered orally and is rapidly converted to the active compound A77 1726. The half-life of A77 1726 is long, with values reported as 10–15 days. Steady state plasma concentrations, in the treatment of rheumatoid arthritis, approach 250 μM. The proposed mechanism of A77 1726 is a reduction in lymphocyte proliferation due to inhibition of de novo pyrimidine synthesis and inhibition of tyrosine kinases. Given the need for chemotherapeutics with activity against neoplastic B-cell diseases that possess favorable pharmacokinetic and side effect profiles, we examined the in vitro antiproliferative effect of A77 1726 upon neoplastic B-cell lines, and its in vitro cytotoxic effect upon primary CLL cells. Raji, Ramos, 697, WaC3CD5 and Daudi B-cell lines were treated with A77 1726 (0, 1, 10, 50, 100, 200 and 300 μM) for 24, 48 and 96 hrs in RPMI media supplemented with 10% fetal bovine serum. The antiproliferative effect of was determined using the MTT assay. A77 1726 IC50 values for each cell line are: Raji (36 μM), Ramos (18 μM), 697 (29 μM), WaC3CD5 (83 μM) and Daudi (13 μM). Cell cycle analysis of Raji cells using propidium iodide (PI) staining with FACS analysis, showed a reduction of the fraction of cells in G2 from 19 % to 4.9 % with A77 1726 (200 μM) treatment. A77 1726 binds to albumin, diminishing its effective concentration. Human albumin (3 gm/dl) reduced the effectiveness of A77 1726 (200 μM) upon both Raji and WaC3CD5 cell lines. In the presence of albumin, the number of viable Raji cells increased from 32% to 74%, and for WaC3CD5 cells the value increased from 19% to 78%, as compared to the untreated control cells. Both cell lines multiplied slower in the presence of human albumin, thus the observed antiproliferative effect of A77 1726 was proportionally reduced. A77 1726 reduces de novo pyrimidine synthesis by inhibiting the enzyme dihydroorotate dehydrogenase. The reduction in de novo pyrimidine synthesis can be surmounted by the exogenous addition of uridine to the culture media. The Raji and WaC3CD5 cell lines were incubated with A77 1726 with and without uridine to determine the role of pyrimidine synthesis in A77 1726′s antiproliferative effect upon the cell lines. For the Raji cell line, addition of 50 μM uridine to A77 1726 (200 μM) treated cells increased the number of viable cells from 22% to 62% of the untreated control. For the WaC3CD5 cell line, the addition of uridine did not decrease the antiproliferative effect of A77 1726. These data agree with prior studies that indicated an antiproliferative effect of A77 1726 beyond its inhibition of de novo pyrimidine synthesis. CLL cells do not reproduce in vitro; however, we hypothesized that the pyrimidine-independent effect of A77 1726 may be cytotoxic to CLL cells in vitro. Five negatively selected primary CLL samples were treated with A77 1726 (0, 50, 100, 200 and 300 μM) for 120 hrs and cell viability was determined with the MTT assay. Significant (greater than 40 % of control value) cytotoxicity occurred with 200 μM A77 1726 in 3 of 5 samples. Treatment with 300 μM A77 1726 led to significant killing in all the samples; the mean viability, as compared to untreated control, was 36% (SD 21, N=5). Addition of uridine did not reverse the observed cytotoxic effect of A77 1726 upon CLL cells. Annexin V-FITC/PI staining with FACS analysis confirmed the cytotoxic effect of A77 1726 on CLL cells. Further study of leflunomide in animal models of neoplastic B-cell disorders is warranted.

scholarly journals Synergistic Effect of DHODH Inhibitor PTC299 with DNA Demethylating Agent Decitabine in Myelodysplastic Syndromes

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 5407-5407
Author(s):  
Kensuke Kayamori ◽  
Cheng Zhong ◽  
Daisuke Shinoda ◽  
Shuhei Koide ◽  
Motohiko Oshima ◽  
...  
Keyword(s):  
Synergistic Effect ◽  
Cell Lines ◽  
De Novo ◽  
Enrichment Analysis ◽  
S Phase ◽  
Rna Seq ◽  
Expression Levels ◽  
Pyrimidine Synthesis ◽  
De Novo Pyrimidine Synthesis

Background:Myelodysplastic Syndrome (MDS) is a clonal bone marrow disorder characterized by ineffective and clonal hematopoiesis accompanied by morphological dysplasia and variable cytopenia. There are few treatment options for MDS, and allogenic hematopoietic stem cell transplantation is the only curative option. Dihydroorotate dehydrogenase (DHODH) catalyzes a rate-limiting step in de novo pyrimidine synthesis, the conversion of DHO to orotate. DHODH inhibition has been described recently as a new approach for treating acute myeloid leukemia (AML) by inducing differentiation of diverse AML subclasses. PTC299 represents a novel potent DHODH inhibitor and recently clinical development of PTC299 as a potential treatment option for acute leukemia was initiated. Here, we explored the efficacy of DHODH inhibitor PTC299 for MDS. Methods:Anti-MDS efficacy of PTC299 was studied using human MDS cell lines and primary MDS cells in vitro. PTC299 was synthesized at PTC Therapeutics Inc. Mechanistic studies were conducted via flow cytometric analysis and RNA-sequencing (RNA-seq). Gene expression levels were analyzed by quantitative PCR (qPCR). Results:PTC299 inhibited proliferation of AML cell lines and induced their differentiation. As previously reported in other DHODH inhibitors, upregulation of CD11b was observed after PTC299 treatment in both HL-60 and THP-1 cells. In addition, PTC299 inhibited the proliferation of MDS cell lines, MDSL and SKM-1 cells, with EC50s of 12.6 nM in MDSL cells and 19.7 nM in SKM-1 cells. The inhibitory effect was reversed by the exogenous addition of 100 µM uridine, which bypasses the requirement for de novo pyrimidine synthesis by feeding into the salvage pathway, thereby negating the need for DHODH. Because the basal expression levels of CD11b are high in MDS cells, we examined the expression levels of CD38. Both cell lines showed dose-dependent upregulation of CD38 after PTC299 treatment. To investigate the possible synergism between PTC299 and decitabine, we treated MDSL and SKM-1 cells with increasing concentrations of PTC299 and decitabine as single agents or in combination. After 3 days of culture, cells were analyzed by MTS assays. PTC299 and decitabine exerted a enhanced cytotoxic effect on MDSL and SKM-1 cells. Similar results were obtained with primary MDS samples. In Annexin/PI assays, the percentage of apoptotic cells was increased by combination of PTC299 with decitabine in both cell lines. Mechanistically, treatment with PTC299 induced an intra-S-phase arrestfollowed by entry intoapoptotic cell death. It has also been reported that the expression of p53 is increased in response to the intra-S-phase arrest. To understand the genome-wide effects and target genes of PTC299 and the combination with decitabine, we performed RNA-seq of MDSL and SKM-1 cells treated with PTC299, decitabine, or the combination of both agents versus DMSO-treated cells. Gene set enrichment analysis (GSEA) using our RNA-seq data confirmed that MYC target gene sets were negatively enriched in both PTC299-, decitabine- and combination- treated cells. KEGG pathway enrichment analysis revealed activation of genes associated with apoptosis in both cell lines. To better elucidate a synergistic effect of PTC299 and decitabine, we performed qPCR of CDKN1A, which is a major target of p53 activity. The mRNA expression levels of CDKN1A were upregulated after treatment with PTC299, which was further enhanced by the combination with decitabine. Conclusions:Our result indicate that the DHODH inhibitor PTC299 suppresses the growth of MDS cells in vitro and acts in at least an additive and possibly synergistic manner with decitabine in this process. This combination therapy could be a new therapeutic option for the treatment of MDS. Disclosures Lennox: PTC Therapeutics: Employment. Weetall:PTC Therapeutics: Employment. Sheedy:PTC Therapeutics: Employment.

scholarly journals A Novel Approach for Treatment of T-Cell Malignancies: Targeting T-Cell Receptor Vβ Families

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 28-29
Author(s):  
Jie Wang ◽  
Katarzyna Urbanska ◽  
Prannda Sharma ◽  
Mathilde Poussin ◽  
Reza Nejati ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
Cell Line ◽  
Cell Lines ◽  
Cell Receptor ◽  
Brentuximab Vedotin ◽  
T Cell Lymphomas ◽  
T Cell Malignancies

Background: Peripheral T-cell lymphomas (PTCL) encompass a highly heterogeneous group of T-cell malignancies and are generally associated with a poor prognosis. Combination chemotherapy results in consistently poorer outcomes for T-cell lymphomas compared with B-cell lymphomas.1 There is an urgent clinical need to develop novel approaches to treatment of PTCL. While CD19- and CD20-directed immunotherapies have been successful in the treatment of B-cell malignancies, T-cell malignancies lack suitable immunotherapeutic targets. Brentuximab Vedotin, a CD30 antibody-drug conjugate, is not applicable to PTCL subtypes which do not express CD30.2 Broadly targeting pan-T cell markers is predicted to result in extensive T-cell depletion and clinically significant immune deficiency; therefore, a more tumor-specific antigen that primarily targets the malignant T-cell clone is needed. We reasoned that since malignant T cells are clonal and express the same T-cell receptor (TCR) in a given patient, and since the TCR β chain in human α/β TCRs can be grouped into 24 functional Vβ families targetable by monoclonal antibodies, immunotherapeutic targeting of TCR Vβ families would be an attractive strategy for the treatment of T-cell malignancies. Methods: We developed a flexible approach for targeting TCR Vβ families by engineering T cells to express a CD64 chimeric immune receptor (CD64-CIR), comprising a CD3ζ T cell signaling endodomain, CD28 costimulatory domain, and the high-affinity Fc gamma receptor I, CD64. T cells expressing CD64-CIR are predicted to be directed to tumor cells by Vβ-specific monoclonal antibodies that target tumor cell TCR, leading to T cell activation and induction of tumor cell death by T cell-mediated cytotoxicity. Results: This concept was first evaluated in vitro using cell lines. SupT1 T-cell lymphoblasts, which do not express a native functioning TCR, were stably transduced to express a Vβ12+ MART-1 specific TCR, resulting in a Vβ12 TCR expressing target T cell line.3 Vβ family specific cytolysis was confirmed by chromium release assays using co-culture of CD64 CIR transduced T cells with the engineered SupT1-Vβ12 cell line in the presence of Vβ12 monoclonal antibody. Percent specific lysis was calculated as (experimental - spontaneous lysis / maximal - spontaneous lysis) x 100. Controls using no antibody, Vβ8 antibody, and untransduced T cells did not show significant cytolysis (figure A). Next, the Jurkat T cell leukemic cell line, which expresses a native Vβ8 TCR, was used as targets in co-culture. Again, Vβ family target specific cytolysis was achieved in the presence of CD64 CIR T cells and Vβ8, but not Vβ12 control antibody. Having demonstrated Vβ family specific cytolysis in vitro using target T cell lines, we next evaluated TCR Vβ family targeting in vivo. Immunodeficient mice were injected with SupT1-Vβ12 or Jurkat T cells with the appropriate targeting Vβ antibody, and either CD64 CIR T cells or control untransduced T cells. The cell lines were transfected with firefly luciferase and tumor growth was measured by bioluminescence. The CD64 CIR T cells, but not untransduced T cells, in conjunction with the appropriate Vβ antibody, successfully controlled tumor growth (figure B). Our results provide proof-of-concept that TCR Vβ family specific T cell-mediated cytolysis is feasible, and informs the development of novel immunotherapies that target TCR Vβ families in T-cell malignancies. Unlike approaches that target pan-T cell antigens, this approach is not expected to cause substantial immune deficiency and could lead to a significant advance in the treatment of T-cell malignancies including PTCL. References 1. Coiffier B, Brousse N, Peuchmaur M, et al. Peripheral T-cell lymphomas have a worse prognosis than B-cell lymphomas: a prospective study of 361 immunophenotyped patients treated with the LNH-84 regimen. The GELA (Groupe d'Etude des Lymphomes Agressives). Ann Oncol Off J Eur Soc Med Oncol. 1990;1(1):45-50. 2. Horwitz SM, Advani RH, Bartlett NL, et al. Objective responses in relapsed T-cell lymphomas with single agent brentuximab vedotin. Blood. 2014;123(20):3095-3100. 3. Hughes MS, Yu YYL, Dudley ME, et al. Transfer of a TCR Gene Derived from a Patient with a Marked Antitumor Response Conveys Highly Active T-Cell Effector Functions. Hum Gene Ther. 2005;16(4):457-472. Figure Disclosures Schuster: Novartis, Genentech, Inc./ F. Hoffmann-La Roche: Research Funding; AlloGene, AstraZeneca, BeiGene, Genentech, Inc./ F. Hoffmann-La Roche, Juno/Celgene, Loxo Oncology, Nordic Nanovector, Novartis, Tessa Therapeutics: Consultancy, Honoraria.

scholarly journals In vitro cytotoxic study for partially purified resveratrol extracted from grape skin fruit Vitis vinifera

2009 ◽  
Vol 3 (2) ◽  
pp. 40-47
Author(s):  
Zainab Y. Mohammed ◽  
Essam F. Al-Jumaily ◽  
Nahi Y. Yaseen
Keyword(s):  
Cell Line ◽  
Cell Lines ◽  
Cytotoxic Effect ◽  
Inhibitory Effect ◽  
Mammary Adenocarcinoma ◽  
Dependent Manner ◽  
Grape Skin ◽  
Grape Fruit ◽  
Glass Column

The partial purified resveratrol was obtained from the skin of black grape fruit cultivated in Iraq using 80% ethanolic solution, then an acid hydrolysis with 10% HCl solution for (10–30) min at 60Cº was carried out. The aglycone moiety was taken with an organic solvent (chloroform), then using an open glass column packed with silica gelG 60 as a stationary phase and a mobile phase of; benzene: methanol: actic acid (20:4:1). The study utilized an in vitro evaluation for the cytotoxic effect of the partially purified resveratrol on some cell lines including, the murine mammary adenocarcinoma (Ahmed –Mohammed –Nahi–2003 -AMN -3) cell line; the human laryngeal carcinoma (Hep -2) cell line and the Rat Embryo Fibroblast (REF) cell line at different concentrations and different exposure time of treatment. The partial purified resveratrol extract concentrations ranging (7.8–4000) µg/ml in a two fold serial dilutions were used to treat the three types of cell lines for 48 and 72 hours intervals. AMN-3 cell lines showed highest sensitivity toward the cytotoxic effect of the paritial purified resveratrol than other cell lines after 48 hours in a dose dependent manner. While Hep-2 cell line showed novel behavior, the lowest concentration of cell treatment gave the most significant (P< 0.01) inhibitory effect. Only the highest concentration gave significant inhibitory effect (P< 0.01) with the transformed Ref cell line.

scholarly journals Establishment of B-Cell Lymphoma Cell Lines Persistently Infected with Hepatitis C Virus In Vivo and In Vitro: the Apoptotic Effects of Virus Infection

2003 ◽  
Vol 77 (3) ◽  
pp. 2134-2146 ◽  
Author(s):  
Vicky M.-H. Sung ◽  
Shigetaka Shimodaira ◽  
Alison L. Doughty ◽  
Gaston R. Picchio ◽  
Huong Can ◽  
...  
Keyword(s):  
Hepatitis C ◽  
B Cell ◽  
Cell Line ◽  
Cell Lines ◽  
Culture System ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
Hcv Rna

ABSTRACT Hepatitis C virus (HCV) is a major cause of chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. Studies of HCV replication and pathogenesis have so far been hampered by the lack of an efficient tissue culture system for propagating HCV in vitro. Although HCV is primarily a hepatotropic virus, an increasing body of evidence suggests that HCV also replicates in extrahepatic tissues in natural infection. In this study, we established a B-cell line (SB) from an HCV-infected non-Hodgkin's B-cell lymphoma. HCV RNA and proteins were detectable by RNase protection assay and immunoblotting. The cell line continuously produces infectious HCV virions in culture. The virus particles produced from the culture had a buoyant density of 1.13 to 1.15 g/ml in sucrose and could infect primary human hepatocytes, peripheral blood mononuclear cells (PBMCs), and an established B-cell line (Raji cells) in vitro. The virus from SB cells belongs to genotype 2b. Single-stranded conformational polymorphism and sequence analysis of the viral RNA quasispecies indicated that the virus present in SB cells most likely originated from the patient's spleen and had an HCV RNA quasispecies pattern distinct from that in the serum. The virus production from the infected primary hepatocytes showed cyclic variations. In addition, we have succeeded in establishing several Epstein-Barr virus-immortalized B-cell lines from PBMCs of HCV-positive patients. Two of these cell lines are positive for HCV RNA as detected by reverse transcriptase PCR and for the nonstructural protein NS3 by immunofluorescence staining. These observations unequivocally establish that HCV infects B cells in vivo and in vitro. HCV-infected cell lines show significantly enhanced apoptosis. These B-cell lines provide a reproducible cell culture system for studying the complete replication cycle and biology of HCV infections.

scholarly journals Gene involved in the 3q27 translocation associated with B-cell lymphoma, BCL5, encodes a Kruppel-like zinc-finger protein

Blood ◽  
1994 ◽  
Vol 83 (1) ◽  
pp. 26-32 ◽  
Author(s):  
T Miki ◽  
N Kawamata ◽  
S Hirosawa ◽  
N Aoki
Keyword(s):  
B Cell ◽  
Cell Line ◽  
Cell Lines ◽  
Zinc Finger ◽  
Zinc Finger Protein ◽  
Cdna Probe ◽  
B Cell Lymphoma ◽  
Nucleotide Sequencing ◽  
Sequencing Analysis

Abstract Chromosomal translocations involving band 3q27 are the recently described nonrandom cytogenetic abnormalities in B-cell malignancies. We have previously cloned the breakpoint region of 3q27, designated as the BCL5 locus, from the B-cell line carrying the t(3;22). The cDNA for the BCL5 gene was cloned from the human liver cDNA library. The nucleotide sequencing analysis showed that the BCL5 gene encodes a potential transcription factor containing six repeats of the Cys2-His2 zinc-finger motif resembling the Drosophila segmentation gene Kruppel. The calculated molecular weight was 78.8 kD, which was supported by an in vitro transcription and translation experiment. A part of the sequence was essentially identical to that of a genomic fragment, ZNF51, previously reported to be located at 3qter. The translocation occurred in the 5′ region of the BCL5 gene, and the protein-coding exons were fused to the Ig-lambda gene in a head-to-head configuration in the cell line carrying t(3;22). The BCL5 cDNA probe detected a major transcript of 3.8 kb in Burkitt's lymphoma cell lines and an aberrant transcript in the t(3;22) cell line, whereas no transcript was detected in myeloid, monocytoid, erythroid, T-lymphoid, and Epstein-Barr virus- immortalized B-lymphoblastoid cell lines.

scholarly journals Biochemical identification of a neutral sphingomyelinase 1 (NSM1)-like enzyme as the major NSM activity in the DT40 B-cell line: absence of a role in the apoptotic response to endoplasmic reticulum stress

2002 ◽  
Vol 365 (1) ◽  
pp. 69-77 ◽  
Author(s):  
Amanda C. FENSOME ◽  
Michelle JOSEPHS ◽  
Matilda KATAN ◽  
Fernando RODRIGUES-LIMA
Keyword(s):  
Endoplasmic Reticulum ◽  
Er Stress ◽  
B Cell ◽  
Cell Line ◽  
Redox Regulation ◽  
De Novo ◽  
Neutral Sphingomyelinase ◽  
Complete Purification ◽  
Dt40 Cells

DT40 cells have approx. 10-fold higher Mg2+-dependent neutral sphingomyelinase (NSM) activity in comparison with other B-cell lines and contain very low acidic sphingomyelinase activity. Purification of this activity from DT40 cell membranes suggested the presence of one major NSM isoform. Although complete purification of this isoform could not be achieved, partially purified fractions were examined further with regard to the known characteristics of previously partially purified NSMs and the two cloned enzymes exhibiting in vitro NSM activity (NSM1 and NSM2). For a direct comparative study, highly purified brain preparations, purified NSM1 protein and Bacillus cereus enzyme were used. Analysis of the enzymic properties of the partially purified DT40 NSM, such as cation dependence, substrate specificity, redox regulation and stimulation by phosphatidylserine, together with the localization of this enzyme to the endoplasmic reticulum (ER), suggested that this NSM from DT40 cells corresponds to NSM1. Further studies aimed to correlate presence of the high levels of this NSM1-like activity in DT40 cells with the ability of these cells to accumulate ceramide and undergo apoptosis. When DT40 cells were stimulated to apoptose by a variety of agents, including the ER stress, an increase in endogenous ceramide levels was observed. However, these responses were not enhanced compared with another B-cell line (Nalm-6), characterized by low sphingomyelinase activity. In addition, DT40 cells were not more susceptible to ceramide accumulation and apoptosis when exposed to the ER stress compared with other apoptotic agents. Inhibition of de novo synthesis of ceramide partially inhibited its accumulation, indicating that the ceramide production in DT40 cells could be complex and, under some conditions, could involve both sphingomyelin hydrolysis and ceramide synthesis.

The Suppressor of Cytokine Signaling-3 Gene Is Overexpressed in Human De Novo Follicular Lymphomas and Promotes IL-3-Independent Proliferation of the BaF3 Pro-B Cell Line.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 1107-1107
Author(s):  
Jacqueline C. Barrientos ◽  
Sofya Rodov ◽  
Arthur W. Zieske ◽  
K. Gary J. Vanasse
Keyword(s):  
Cell Proliferation ◽  
B Cells ◽  
B Cell ◽  
Cell Line ◽  
Cell Lines ◽  
De Novo ◽  
Myeloid Cells ◽  
Negative Regulator ◽  
Cytokine Signaling ◽  
Socs3 Protein

Abstract The recent generation of mice lacking functional SOCS3 in hepatocytes, macrophages, and neutrophils reveals SOCS3 to be an essential regulator of IL-6 signaling via mediation of gp130-related cellular complexes, as well as a negative regulator of G-CSF signaling in myeloid cells. Although SOCS3 would appear to be a critical physiologic regulator of inflammatory responses, its possible role in hematologic malignancies and the underlying mechanisms which regulate its expression in B cells remain to be clearly defined. We previously showed that CD19+ B cells isolated from Eμ-Bcl-2 transgenic mice express high levels of SOCS3 in addition to overexpression of Bcl-2. Moreover, hematopoietic cell lines transduced to stably overexpress Bcl-2 exhibited marked induction of SOCS3 compared to controls, suggesting Bcl-2-associated pathways may play a role in the induction of SOCS3. In the current study, we describe SOCS3 overexpression limited to neoplastic follicular lymphoma (FL) cells in Bcl-2-associated human de novo FL and show that overexpression of SOCS3 is capable of stimulating cytokine-independent cellular proliferation of the BaF3 pro-B cell line. We measured SOCS3 protein levels by immunohistochemistry in paraffin-embedded biopsies from twelve patients diagnosed with de novo, untreated histologic grade I or II FL which harbored t(14;18) and Bcl-2 overexpression. In 9/12 de novo FL cases examined, immunostaining with two distinct antibodies to SOCS3 revealed marked overexpression of SOCS3 protein that, within the follicular center cell region, was limited to neoplastic FL cells and co-localized with Bcl-2 primarily in the nucleus of positive cells. In contrast, SOCS3 protein was not detected by immunostaining in germinal center follicular B cells from benign hyperplastic tonsil tissue. To further evaluate the role of SOCS3 in B cell biology, the IL-3-dependent BaF3 pro-B cell line was stably transduced with either a retroviral expression construct containing a 675bp human SOCS3 cDNA (BaF3SOCS3) or with vector only control (BaF3Δ). Whereas no SOCS3 protein was detected in control cells, high level expression of SOCS3 in transduced BaF3SOCS3 cells was confirmed by Western analysis using SOCS3 anti-sera. Furthermore, Bcl-2 protein was not detected in either BaF3SOCS3 or control cell lines. 2 x 105 BaF3SOCS3, BaF3Δ, and non-transduced BaF3 cell lines were initially grown in the presence 10% fetal bovine serum (FBS) and 5% WEHI 3B cell-conditioned medium as a source of IL-3. IL-3 was then removed by washing with DMEM/10% FBS. Cell viability was then measured by recording absorbance at 490nm using incorporation of the MTS tetrazolium compound. Interestingly, BaF3SOCS3 cells overexpressing SOCS3 did not undergo apoptosis but were able to proliferate in the absence of IL-3, with percent viable cells approaching 400% at &gt; 96 hours, which represented the final time-point measured. In contrast, BaF3Δ and non-transduced BaF3 cells underwent apoptotic cell death between 8 and 36 hours in response to IL-3 withdrawal. Thus, SOCS3 overexpression confers IL-3-independent cell proliferation to the BaF3 cell line. These data indicate that unlike its negative regulatory effect on G-CSF signaling in myeloid cells, overexpression of SOCS3 in B cells may promote B cell proliferation rather than growth suppression and may play an important role in the pathogenesis of de novo FL in humans.

scholarly journals Function and Evolution of Plasmid-Borne Genes for Pyrimidine Biosynthesis in Borrelia spp

2006 ◽  
Vol 188 (3) ◽  
pp. 909-918 ◽  
Author(s):  
Jianmin Zhong ◽  
Stephane Skouloubris ◽  
Qiyuan Dai ◽  
Hannu Myllykallio ◽  
Alan G. Barbour
Keyword(s):  
Thymidylate Synthase ◽  
De Novo ◽  
Linear Plasmid ◽  
Borrelia Hermsii ◽  
Borrelia Garinii ◽  
E Coli ◽  
Pyrimidine Synthesis ◽  
De Novo Pyrimidine Synthesis

ABSTRACT The thyX gene for thymidylate synthase of the Lyme borreliosis (LB) agent Borrelia burgdorferi is located in a 54-kb linear plasmid. In the present study, we identified an orthologous thymidylate synthase gene in the relapsing fever (RF) agent Borrelia hermsii, located it in a 180-kb linear plasmid, and demonstrated its expression. The functions of the B. hermsii and B. burgdorferi thyX gene products were evaluated both in vivo, by complementation of a thymidylate synthase-deficient Escherichia coli mutant, and in vitro, by testing their activities after purification. The B. hermsii thyX gene complemented the thyA mutation in E. coli, and purified B. hermsii ThyX protein catalyzed the conversion of dTMP from dUMP. In contrast, the B. burgdorferi ThyX protein had only weakly detectable activity in vitro, and the B. burgdorferi thyX gene did not provide complementation in vivo. The lack of activity of B. burgdorferi's ThyX protein was associated with the substitution of a cysteine for a highly conserved arginine at position 91. The B. hermsii thyX locus was further distinguished by the downstream presence in the plasmid of orthologues of nrdI, nrdE, and nrdF, which encode the subunits of ribonucleoside diphosphate reductase and which are not present in the LB agents B. burgdorferi and Borrelia garinii. Phylogenetic analysis suggested that the nrdIEF cluster of B. hermsii was acquired by horizontal gene transfer. These findings indicate that Borrelia spp. causing RF have a greater capability for de novo pyrimidine synthesis than those causing LB, thus providing a basis for some of the biological differences between the two groups of pathogens.

scholarly journals Targeted Inhibition of PI3K α/δ Is Synergistic with BCL-2 Blockade in Genetically Defined Subtypes of DLBCL

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 39-39
Author(s):  
Kamil Bojarczuk ◽  
Kirsty Wienand ◽  
Jeremy A. Ryan ◽  
Linfeng Chen ◽  
Mariana Villalobos-Ortiz ◽  
...  
Keyword(s):  
Tumor Growth ◽  
B Cell ◽  
Cell Line ◽  
Cell Lines ◽  
Research Funding ◽  
Single Agent ◽  
Research Report ◽  
Genetic Bases

Abstract Diffuse large B-cell lymphoma (DLBCL) is a genetically heterogeneous disease that is transcriptionally classified into germinal center B-cell (GCB) and activated B-cell (ABC) subtypes. A subset of both GCB- and ABC-DLBCLs are dependent on B-cell receptor (BCR) signaling. Previously, we defined distinct BCR/PI3K-mediated survival pathways and subtype-specific apoptotic mechanisms in BCR-dependent DLBCLs (Cancer Cell 2013 23:826). In BCR-dependent DLBCLs with low baseline NF-κB activity (GCB tumors), targeted inhibition or genetic depletion of BCR/PI3K pathway components induced expression of the pro-apoptotic HRK protein. In BCR-dependent DLBCLs with high NF-κB activity (ABC tumors), BCR/PI3K inhibition decreased expression of the anti-apoptotic NF-κB target gene, BFL1. Our recent analyses revealed genetic bases for perturbed BCR/PI3K signaling and defined poor prognosis DLBCL subsets with discrete BCR/PI3K/TLR pathway alterations (Nat Med 2018 24:679). Cluster 3 DLBCLs (largely GCB tumors) exhibited frequent PTEN deletions/mutations and GNA13 mutations. Cluster 5 DLBCLs (largely ABC tumors) had frequent MYD88L265P and CD79B mutations that often occurred together. These DLBCL subtypes also had different genetic mechanisms for deregulated BCL2 expression - BCL2 translocations in Cluster 3 and focal (18q21.33) or arm level (18q) BCL2 copy number gains in Cluster 5. These observations prompted us to explore the activity of PI3K inhibitors and BCL2 blockade in genetically defined DLBCLs. We utilized a panel of 10 well characterized DLBCL cell line models, a subset of which exhibited hallmark genetic features of Cluster 3 and Cluster 5. We first evaluated the cytotoxic activity of isoform-specific, dual PI3Kα/δ and pan-PI3K inhibitors. In in vitro assays, the PI3Kα/δ inhibitor, copanlisib, exhibited the highest cytotoxicity in all BCR-dependent DLBCLs. We next assessed the transcriptional abundance of BCL2 family genes in the DLBCLs following copanlisib treatment. In BCR-dependent GCB-DLBCLs, there was highly significant induction of the pro-apoptotic HRK. In BCR-dependent ABC-DLBCLs, we observed significant down-regulation of the anti-apoptotic BFL1 protein and another NF-κB target gene, BCLxL (the anti-apoptotic partner of HRK). We then used BH3 profiling, to identify dependencies on certain BCL2 family members and to correlate these data with sensitivity to copanlisib. BCLxL dependency significantly correlated with sensitivity to copanlisib. Importantly, the BCLxL dependency was highest in DLBCL cell lines that exhibited either transcriptional up-regulation of HRK or down-regulation of BCLxL following copanlisib treatment. In all our DLBCL cell lines, PI3Kα/δ inhibition did not alter BCL2 expression. Given the genetic bases for BCL-2 deregulation in a subset of these DLBCLs, we next assessed the activity of the single-agent BCL2 inhibitor, venetoclax, in in vitro cytotoxicity assays. A subset of DLBCL cell lines was partially or completely resistant to venetoclax despite having genetic alterations of BCL2. We postulated that BCR-dependent DLBCLs with structural alterations of BCL2 might exhibit increased sensitivity to combined inhibition of PI3Kα/δ and BCL2 and assessed the cytotoxic activity of copanlisib (0-250 nM) and venetoclax (0-250 nM) in the DLBCL cell line panel. The copanlisib/venetoclax combination was highly synergistic (Chou-Talalay CI<1) in BCR-dependent DLBCL cell lines with genetic bases of BCL2 deregulation. We next assessed copanlisib and venetoclax activity in an in vivo xenograft model using a DLBCL cell line with PTENdel and BCL2 translocation (LY1). In this model, single-agent copanlisib did not delay tumor growth or improve survival. Single-agent venetoclax delayed tumor growth and improved median survival (27 vs 51 days, p<0.0001). Most notably, we found that the combination of copanlisib and venetoclax delayed tumor growth significantly longer than single-agent venetoclax (p<0.0001). Additionally, the combined therapy significantly increased survival in comparison with venetoclax alone (median survival 51 days vs not reached, p<0.0013). Taken together, these results provide in vitro and in vivo pre-clinical evidence for the rational combination of PI3Kα/δ and BCL2 blockade and set the stage for clinical evaluation of copanlisib/venetoclax therapy in patients with genetically defined relapsed/refractory DLBCL. Disclosures Letai: AbbVie: Consultancy, Other: Lab research report; Flash Therapeutics: Equity Ownership; Novartis: Consultancy, Other: Lab research report; Vivid Biosciences: Equity Ownership; AstraZeneca: Consultancy, Other: Lab research report. Shipp:AstraZeneca: Honoraria; Merck: Research Funding; Bristol-Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bayer: Research Funding.

scholarly journals The Cytotoxic Effect of Metformin on RD Cell Line.

2019 ◽  
pp. 85-94
Keyword(s):  
Breast Cancer ◽  
Cell Line ◽  
Cell Lines ◽  
Cytotoxic Effect ◽  
Energy Homeostasis ◽  
Adenosine Monophosphate ◽  
Antiproliferative Effect ◽  
Potentiation Effect ◽  
Diphenyl Tetrazolium Bromide ◽  
Apoptosis Regulation

Background: Cancer is a pathogenesis that happens when modification in collections of normally occurring cells inside the human body occurs leading to non-controlled growth causing a lump called the tumor; this applies to all types of cancers except leukemia (cancer of the blood). Doxorubicin (DOX) is one of the highly effective anti-neoplastic drugs of the anthracycline's family used to treat many pediatric and adult cancers, e.g. solid tumors, lymphomas, leukemia and breast cancer. Doxorubicin is known to produce severe cytotoxicity. Metformin (Met) is a biguanide used for type 2 diabetes mellitus. Metformin have cytoprotective effect in addition to reducing basal and postprandial levels of glucose by decreasing the production of ROS, maintaining energy homeostasis and apoptosis regulation by its activation of adenosine monophosphate-activated protein kinase (AMPK). Met has also the ability to increase apoptotic factors and suppression of proliferation thus MET consider as cytotoxic and anti-proliferative drug. Objectives: This study was designed to investigate the cytotoxic and antiproliferative effect of Met comparing to DOX as a control in RD cell, also combination of both. Materials and Methods: Cell lines that used (Epithelial cells as a normal cell line and RD cell line was taken from human breast cancer) cultured in suitable media potentiated with different concentrations of heat-inactivated human serum. MTT assay (3-(4,5-Dimethylthiazol-2-yl)2,5-diphenyl tetrazolium bromide) using for detection of cytotoxicity in Epithelial and RD cell lines for duration 72hrs. Results: The results showed that treatment with DOX, MET and combination DOX with MET there is significant (p≤ 0.5) cytotoxic, apoptotic and antiproliferative effect and there is potentiation effect between MET and DOX on tumor cells when treated by combination DOX with MET also Met showed a valuable cytotoxic effect through the detection of IC50. Conclusion: From the results, it can be concluded that Metformin have a good cytotoxic and antiproliferative effect on tumor cell lines.

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