scholarly journals Effects of Proteasome Inhibition in the Anti-Tumor Activity of Venetoclax in Mantle Cell Lymphoma Pre-Clinical Models

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 2942-2942
Author(s):  
Shalin K. Kothari ◽  
Cory Mavis ◽  
Juan Gu ◽  
Francisco J. Hernandez-Ilizaliturri

Abstract Background: At the molecular level, mantle cell lymphoma (MCL) is characterized by the deregulation of Bcl-2 family members (Mcl-1, BIM) and cell cycle (cyclin D1) regulatory proteins. Perhaps related to this, the clinical outcome of MCL continues to be poor specially for those patients with disease progression after high dose chemotherapy and autologous stem cell rescue and/or BTK inhibitors, stressing the need to develop novel therapeutic strategies or optimize current available options. Venetoclax (V), a highly selective Bcl-2 inhibitor, has shown modest activity against relapsed/refractory MCL. Over-expression of Mcl-1 has been postulated to be a mechanism of resistance to V limiting its anti-tumor activity in subtypes of lymphoma including MCL. The lethality by proteasome inhibitors (PIs) has been associated with changes in the Bcl-2 family members (Bax, Noxa, Mcl-1 and Bcl-XL) in lymphoma pre-clinical models, making them ideal agents to combine with V. To this end, we studied the anti-tumor activity of combining PIs with V in MCL pre-clinical models. Materials and Methods: A panel cytarabine sensitive (Rec-1, Jeko, Granta, HBL-2, Z-138 and Mino) and resistant (araC) cell lines (Jeko araC, HBL-2 araC, and Mino araC) were exposed to V, Bortezomib (BTZ), carfilzomib (CFZ), or ixazomib (IXZ) for 24, 48 and 72 hours. Cell viability was calculated measuring the ATP content. IC50 drug concentrations were calculated for each agent. Subsequently, MCL cell lines were exposed to escalating doses of V (0.001uM-5uM) and CFZ (1.5625nM-50nM), BTZ (3.125nM-100nM) or IXZ (3.125nM-100nM). In addition, primary tumor cells isolated from B-cell lymphoma patients (N=21) including MCL patients were exposed to V +/- BTZ or CFZ for 48 hrs. Cell viability was determined by Cell Titerglo. Coefficient of synergy were calculated using CalcuSyn software program. Induction of apoptosis was detected by Annexin V/Propidium iodine staining and PARP cleavage. Changes in Bcl-2 and cell cycle regulatory proteins were evaluated by Western blotting in HBL-2 cells. For in vivo experiments, 6-8 weeks old severe combined immunodeficiency (SCID) mice were inoculated with 10x106 HBL-2 cells via tail vein injection (IV). Subsequently, SCID mice were treated with V (100mg/kg/dose via gastric lavage on days 3-7, 10-14 and 17-21) or IXZ (6mg/kg/dose IV days 3, 6, 10, 13, 17 and 20) or combination of both agents. A group of untreated animals was used as a control. Differences in survival were evaluated between treatment groups. Results: In vitro exposure of MCL cell lines to either V, BTZ, CFZ, and IXZ induced cell death in a dose- and time-dependent manner. Significant synergistic activity was observed by combining both V with CFZ or IXZ at known sub-therapeutic and therapeutic doses of individual agents measured by ATP content and apoptosis potential. Anti-tumor activity was observed in cytarabine sensitive and resistant cell lines. Similar findings were observed in primary tumor cells isolated from B-cell lymphoma patients. In vitro exposure of MCL cell lines with the lowest IC50 (HBL-2) to V and PIs (BTZ, CFZ, or IXZ) resulted in the upregulation of Noxa, BIM, Mcl-1 cleavage form (pro-apoptotic) and downregulation of Bcl-XL leading to PARP cleavage and apoptosis. In vivo treatment of MCL bearing SCID mice with V resulted in significant anti-tumor activity when compared to single agent IXZ treated or control animals. Of interest, MCL bearing SCID animals treated with V and IXZ exhibited a better disease control and the survival was longer than SCID animals treated with V or IXZ single agent (P<0.05). Conclusion: Our data suggests that V exhibits strong synergistic activity with PIs, especially with CFZ (in vitro) or IXZ (in vitro and in vivo). Together, our data supports the evaluation of V in combination with readily available novel PIs (IXZ or CFZ) in relapsed/refractory MCL. (Supported by LRF grant 555463, an NIH grant R01 CA136907-01A1 and a grant from The Roswell Park Cancer Institute Alliance Foundation) Disclosures No relevant conflicts of interest to declare.

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 2605-2605
Author(s):  
Carmelo Carlo-Stella ◽  
Cristiana Lavazza ◽  
Arianna Giacomini ◽  
Loredana Cleris ◽  
Daniela Sia ◽  
...  

Abstract Introduction: The multikinase inhibitor Sorafenib (Nexavar, Bayer) exerts a remarkable activity against a variety of nonhematological tumors by blocking tumor cell proliferation and angiogenesis through the inhibition of the RAF/MEK/ERK pathway, as well as the receptor tyrosine kinases vascular endothelial growth factor receptors (VEGFRs), platelet-derived growth factor receptor (PDGFR), c-KIT, Flt3, and RET. Several lines of evidence suggest that sorafenib might have a relevant clinical impact in the therapy of malignant lymphomas by overcoming the cytoprotective effects of ERK, Mcl-1, and Bcl-XL. However, preclinical data establishing a rationale for the clinical use of sorafenib in lymphomas are still lacking. The present studies aimed to investigate the activity and the mechanism(s) of action of sorafenib in human lymphomas. Methods: The effects of sorafenib were evaluated in vitro using a panel of six human cell lines of different phenotypes, including JVM-2 (B-Chronic Lymphocytic Leukemia), Granta-519 (Mantle Cell Lymphoma), DOHH2 (Follicular Lymphoma), SU-DHL-4V (Diffuse Large B-Cell Lymphoma), HD-MY-Z (Hodgkin Lymphoma), and KMS-11 (Multiple Myeloma) cell lines. Additionally, the antitumor efficacy and mechanism of action of sorafenib were investigated in vivo by means of five lymphoma xenograft models in nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice. Results: In vitro, the response of cell lines to sorafenib (1–10 μM for 24–48 hours) was evaluated by detecting apoptotic cell death with the annexin-V/propidium iodide double staining assay, and viable cell countings with the Trypan blue dye exclusion test. All 6 cell lines responded to sorafenib with values of 50% inhibitory concentrations ranging from 1 to 7.5 μM. In contrast, normal CD34+ cells remain insensitive to the drug up to 15 μM. Despite significant rates of sorafenib-induced apoptosis were seen in all cell lines, activation of caspase-3 analyzed by fluorescent-activated cell sorter was only detected in DOHH-2 and JVM-2 cell lines. The phosphorylation status of mitogen-activated protein kinase (MAPK) was investigated using the human phospho-MAPK Array kit (R&D systems), analyzed with the open source imaging software ImageJ (http://rsb.info.nih.gov/ij/), and then validated by Western blotting. Sorafenib induced a significant reduction of pAkt1, pAkt2, and pAkt3 in SU-DHL-4V, Granta-519, and JVM-2 cell lines, whereas p38 phosphorylation levels were significantly reduced in all but one cell line (KMS-11). Reduced levels of pMEK, pERK1 and pERK2 were detected in SU-DHL-4V, KMS-11, Granta-519, and HD-MY-Z cell lines. Down-regulation of MCL-1 was seen in HD-MY-Z, JVM-2, and DOHH-2 cell lines. In vivo, the activity of sorafenib was evaluated in NOD/SCID mice bearing subcutaneous tumor nodules. Animals with tumors averaging from 140 to 160 mg were randomly grouped to receive sorafenib (90 mg/kg body weight, IP, once daily for 15 days) or control vehicle. Sorafenib significantly (P ≤0.001) reduced the growth of subcutaneous HD-MY-Z, KMS-11, Granta-519, SU-DHL-4V, and JVM-2 nodules, with values of tumor growth inhibition of 70%, 52%, 40%, 37%, and 24%, respectively. In control mice, TUNEL staining of tumor sections showed large areas of viable cells without significant necrosis, whereas a 2- to 5-fold increase of necrotic areas was detected in sorafenib-treated mice bearing the different lymphoma xenografts. Analysis of tumor vasculature by means of in vivo biotinylation of endothelial cells with sulfo-NHS-LC-biotin showed a 30% to 60% reduction of vessel density in sorafenib-treated mice bearing the different lymphoma xenografts. Conclusions: Sorafenib efficiently targets a variety of human lymphomas representative of different phenotypes by inhibiting tumor angiogenesis and directly affecting tumor cell survival. Our preclinical data establish a rationale for exploring the clinical activity of sorafenib in human lymphomas.


Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 5379-5379
Author(s):  
Sumera Khan ◽  
Kyle Runckel ◽  
Cory Mavis ◽  
Matthew J. Barth ◽  
Francisco J. Hernandez-Ilizaliturri

Abstract Background: The addition of Rituximab to front-line therapy has improved clinical outcomes in diffuse large B-cell lymphoma (DLBCL), but it has also altered the biology of relapsed/refractory disease. To better understand the mechanisms responsible for Rituximab associated chemotherapy cross-resistance our group developed and characterized several Rituximab resistance cell lines (RRCL). We previously demonstrated using SiRNA interference, that X-linked inhibitor of apoptosis (XIAP) is critical for chemotherapy sensitivity and survival in RRCL. MX69, a dual inhibitor of Mdm2 and XIAP that indirectly downregulates XIAP, is undergoing pre-clinical testing. MX69 affects XIAP levels by its effects on the ubiquitination and degradation of endogenous MDM-2, resulting in decrease XIAP translation and activation of caspase 3, 7 and 9 as well as PARP cleavage leading to apoptosis of cancer cells. In our current work, we pharmacologically inhibited XIAP in lymphoma pre-clinical models using MX69. Materials and Methods: A panel of Burkitt's Lymphoma (BL, including RRCL), germinal center B-cell (GCB)-DLBCL (including RRCL), activated B-cell (ABC)-DLBCL, Mantle cell Lymphoma (MCL) and Pre-B cell Leukemia cell lines were exposed to MX69 as a single agent (0-80uM) over 24, 48, 72 hrs and IC50 concentrations were calculated for each cell line. Changes in Mdm2, p53, XIAP and PARP expressions were determined following MX69 exposure (at IC50 doses) for 24 hrs. Induction of apoptosis was evaluated by Annexin V/propidium iodine staining. Subsequently, cell lines were exposed to MX69 (0-80 uM), in combination with Doxorubicin (0-1uM), Cytarabine(0-50uM), Vincristine (0-10nM), Etoposide(0-50uM), Carboplatin (0-20uM), Ixazomib (0-1.5uM), Ibrutinib (0-20uM) and Venetoclax (0-10uM) for 48 hours. Cell viability was determined by Cell Titerglo. Coefficient of synergy was calculated using CalcuSyn. Results: In vitro, MX69 single agent exposure induced cell death in a dose and time-dependent manner in all cell lines tested. Western blotting studies confirmed downregulation of Mdm2, XIAP and changes in P53 and PARP, following in vitro exposure to MX69. Induction of apoptosis was observed by flow cytometry in all cell lines tested. The combination of MX69 with Doxorubicin, Cytarabine, Vincristine, Ixazomib, Carboplatin, Etoposide, Ibrutinib, and Venetoclax resulted in significant synergistic activity. The strongest CI of synergy was observed when cell lines were exposed to MX69 and Venetoclax, Ixazomib, Etoposide or Ibrutinib. Conclusion: Our data suggests that in vitro exposure of a wide variety of B-cell lymphoma cell lines (including BL, DLBCL, MCL or RRCL) to MX69 resulted in anti-tumor activity. Perhaps related to its anti-tumor effects, MX69 inhibited XIAP levels. These findings are similar to prior SiRNA XIAP knockdown experiments. Strong synergistic activity was observed when XIAP was combined with various chemotherapy agents and small molecules inhibitors (such as Venetoclax, ixazomib or ibrutinib). Ex vivo experiments using primary tumor cells isolated from lymphoma patients and lymphoma mouse models are been planned. Targeting Mdm2 and XIAP can be an attractive therapeutic strategy in patients with Rituximab-sensitive or -resistant B-cell lymphoma. Disclosures No relevant conflicts of interest to declare.


Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 2757-2757 ◽  
Author(s):  
Matthew J. Barth ◽  
Gopichand Pendurti ◽  
Ping-Chiao Tsai ◽  
Cory Mavis ◽  
Pavel Klener ◽  
...  

Abstract Abstract 2757 MCL is typically characterized by an aggressive clinical course and inevitable development of refractory disease despite early intervention that often includes: immunotherapy (e.g., rituximab), multi-agent induction chemotherapy and consolidation with high dose chemotherapy and autologous stem cell transplant in first remission. Residual disease at the time of stem cell collection is an important cause for treatment failure. There is a need to evaluate more potent anti-CD20 mAbs capable to kill lymphoma cells with low CD20 surface levels. In Burkitt's lymphoma (BL) and diffuse large B-cell lymphoma (DLBCL) pre-clinical models we previously demonstrated that OFA was more potent than rituximab (RIT) in vitro and in vivo. In order to characterize the activity of OFA against MCL, we evaluated the activity of OFA against cytarabine (Ara-C)-sensitive (eg. Mino, Jeko-1, Rec-1, HBL-2, Granta and Z-138); –resistant MCL cell lines (eg. MinoAraCR, Jeko-1AraCR, Rec-1AraCR, HBL-2AraCR and GrantaAraCR); and primary tumor cells derived from MCL patients (n=2). Antibody-dependent cellular cytotoxicity (ADCC) and complement dependent cytotoxicity (CDC) were measured by standard 51Cr release assays in MCL exposed to OFA, RIT or isotype control. OFA vs. RIT direct anti-proliferative effects were measured in by alamar blue reduction assay. Apoptosis following in vitro exposure to OFA or RIT was detected by caspase 3/PARP cleavage. Patient tumor cells were isolated from biopsy specimens by negative selection using magnetic beads and incubated with OFA or RIT +/− human serum as a complement source. Cell viability was determined at 48 hours by CellTiterGlo assay. Surface CD20 and the complement inhibitory proteins (CIPs) (CD55 and CD59) density in MCL cell lines was determined by flow cytometry (Image stream) and compared to BL or DLBCL cell lines. For in vivo experiments 6–8 week-old SID mice were inoculated subcutaneously with 5×106 matrigel suspended Z-138 cells. Upon tumor engraftment, mice were assigned to RIT (10mg/kg), OFA (10mg/kg) or control groups. Tumor growth curves were calculated for each group. Mice were sacrificed if tumor size reached >2cm in any dimension. After 6 months, survival was analyzed by Kaplan-Meier analysis and compared by log-rank test. OFA induced significantly higher levels of CDC associated cell lysis compared to RIT in almost all MCL cell lines tested (10/11) (Mino: 53.2% vs 0.2%; MinoAraCR: 72.6% vs. 0.6%; Jeko-1: 33.4% vs. 9.8%; Jeko-1AraCR: 38.3% vs. 2.8%; REC-1: 17% vs 3%; Rec-1AraCR: 7.8% vs. 0.2%; HBL-2: 27.1% vs. 19.2%; HBL-2AraCR: 86.6% vs. 72.2%; GrantaAraCR: 17% vs 0.9%; Z-138: 56.4% vs. 0.65%; all p-values <0.05). No differences in RIT or OFA mediated ADCC or direct signaling was observed. As previously noted in BL and DLBCL models, OFA was capable of inducing a higher degree of CMC even at low CD20 levels in contrast to RIT. In vivo, OFA slowed tumor growth, and prolonged survival in Z-138 bearing SCID mice compared to RIT (median survival for RIT was 127 days vs. not reached for OFA treated animals; p<0.05). Our data suggest that, OFA is more potent than RIT against Ara-C-sensitive and –resistant MCL cells in vitro, delays tumor growth and prolongs survival compared to RIT in an in vivo MCL SCID mouse model, and retains CDC activity despite low CD20 and high CIP surface expression levels. OFA appears to be a promising mAb targeting CD20 in MCL and is undergoing clinical testing in the front-line setting (NCT01527149). Disclosures: Czuczman: Genmab: Unrestricted Research Grant Other.


Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 3941-3941
Author(s):  
David M Goldenberg ◽  
Serengulam Govindan ◽  
Tom M Cardillo ◽  
Robert M Sharkey

Abstract Abstract 3941 Background: Monoclonal antibody (MAb) therapy has had a significant impact on the management of B-cell malignancies, but is most often used in combination with chemotherapy. We developed an ADC that combines SN-38, the active component of irinotecan, a topoisomerase I inhibitor, with the internalizing, humanized, anti-CD22 IgG, epratuzumab, and determined its activity alone and in combination with an anti-CD20 antibody therapy (veltuzumab). Methods: Epratuzumab was conjugated with SN-38 (E-SN-38) at a mole ratio of ∼6:1. The conjugate is designed specifically to be released slowly in the presence of serum (50% released over ∼1.5 days), allowing liberation of the drug when internalized, but also being released locally after being bound to the tumor. In vitro and in vivo studies were performed to assess the activity of the conjugate against several subcutaneously- or intravenously-inoculated B-cell lymphoma cell lines. In vivo studies also examined combination therapy using E-SN-38 and the veltuzumab (V). Results: In vitro studies in 4 B-cell lymphoma cells lines (Daudi, Raji, Ramos, WSU-FSCCL) and 4 acute lymphoblastic lymphoma cell lines (697, REH, MN-60, and RS4;11) expressing varying amounts of CD22 showed an IC50 for E-SN-38 in the nanomolar range, confirming potent activity. Nude mice bearing SC Ramos human lymphoma had significant selective anti-tumor activity compared to a control, non-targeting, IgG-SN-38 conjugate, at a dosing regimen of 75 to 250 μg of the conjugates given twice-weekly for 4 weeks. Significant anti-tumor activity was also found in several other cell lines. When combined with veltuzumab, significant improvement in therapeutic activity was observed. For example, median survival in a WSU-FSCCL human follicular B-cell lymphoma IV model with treatment initiated 5 days after implantation was 42 d (0/10 surviving at 160 d) and 91 d (2/10 surviving) for untreated and veltuzumab-treated animals, respectively; 63d (0/10 surviving after 160 d) and >160 d (with 6/10 surviving) for E-SN-38 and E-SN-38 + V, respectively; and 63 d (0/10) and 91 d (2/10) for non-targeting IgG-SN-38 conjugate alone and combined with V). The E-SN-38 conjugate combined with V was significantly better than all treatment or control groups (P ≤ 0.05). Conclusion: E-SN-38 ADC is a potent therapeutic, even at non-toxic dose levels, and shows significantly enhanced efficacy when combined with anti-CD20 immunotherapy, representing an important new ADC treatment regimen. Disclosures: Goldenberg: Immunomedics, Inc.: Membership on an entity's Board of Directors or advisory committees, Patents & Royalties. Govindan:Immunomedics, Inc.: Employment. Cardillo:Immunomedics, Inc.: Employment.


Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 1473-1473 ◽  
Author(s):  
Francisco J. Hernandez-Ilizaliturri ◽  
Suresh Devineni ◽  
Sarika Arora ◽  
Joy Knight ◽  
Myron S. Czuczman

Abstract CMC-544 is an IgG4 CD22-humanized targeted immunoconjugate of calicheamicin. Upon CD22 biding, CMC-544 internalizes inducing cell apoptosis in vitro/in vivo against NHL with minimal modulation of the immune system. In addition to direct cell-death, rituximab, anti-CD20 monoclonal antibody (mAb), can induce complement-dependent cytotoxicity (CDC) and antibody dependent cellular cytotoxicity (ADCC). Combination of mAbs directed against unique tumor-associated targets can potentially enhance anti-tumor activity. Objectives: To study the effects of targeting CD20 and CD22 using rituximab in combination with CMC-544. Material and Methods: For in vitro studies, a panel of NHL cell lines [Raji, SUDHL-4, SU-DHL-10, Ramos, and two rituximab resistant cell lines (RRCL), [2R and 4RH] were exposed to CMC-544 (0.4pg/ml to 0.4μg/ml) +/− Rituximab (10μg/ml) or appropriate controls for 24 or 48 hrs. DNA synthesis was quantified by [H3]Thymidine incorporation and apoptosis was detected by multiparameter flow cytometric analysis and Poly(ADP-ribose) polymerase (PARP) cleavage. For ADCC/CMC studies, 51Cr-labeled NHL cells were exposed to CMC-544 (0.4μg/ml) prior to treatment with rituximab (10mg/ml) and peripheral blood mononuclear cells (Effector: Target ratio 40:1) or human serum, respectively. 51Cr-release was measured and the percentage of lysis was calculated. Statistical analysis of results was performed using the Chi-square test. For in vivo studies, 6–8-week old SCID mice were inoculated via tail vein injection (iv) with Raji cells (1 × 106 on day 0). Animals were assigned to receive 8 doses of either saline, CMC-544 (40μg/kg/dose), rituximab (10mg/kg/dose iv), or rituximab alternating with CMC-544. Antibodies were administered iv every other day starting on day +5. Survival analysis was performed by Kaplan-Meier curves and p values calculated using log rank test. Results: Exposure of various NHL cells to CMC-544 resulted in a dose-dependent significant decrease in cell proliferation and apoptosis. Rituximab-associated CMC or ADCC was not further enhanced by CMC-544 in vitro. In vivo studies demonstrated that the mean survival for animals treated with CMC-544 increased when compared to control mice [64 days (95% C.I. 48–80; 22 days (95% C.I. 21–23), respectively, P=0.001]. To a lesser degree rituximab monotherapy resulted in significant anti-tumor effects and the median survival reached 44 days (95% C.I. 31–56). Notably, animals treated with rituximab in combination with CMC-544 had the longest median survival (not reached at +90 days, log rank P=0.007). Conclusions: Our data suggest targeting CD20 and CD22 by rituximab and CMC-544 resulted in a longer survival in lymphoma-bearing SCID mice. Clinical trials with this combination will be needed to confirm these results for the treatment of lymphoma patients


2019 ◽  
Vol 116 (34) ◽  
pp. 16981-16986 ◽  
Author(s):  
Claudio Scuoppo ◽  
Jiguang Wang ◽  
Mirjana Persaud ◽  
Sandeep K. Mittan ◽  
Katia Basso ◽  
...  

To repurpose compounds for diffuse large B cell lymphoma (DLBCL), we screened a library of drugs and other targeted compounds approved by the US Food and Drug Administration on 9 cell lines and validated the results on a panel of 32 genetically characterized DLBCL cell lines. Dasatinib, a multikinase inhibitor, was effective against 50% of DLBCL cell lines, as well as against in vivo xenografts. Dasatinib was more broadly active than the Bruton kinase inhibitor ibrutinib and overcame ibrutinib resistance. Tumors exhibiting dasatinib resistance were commonly characterized by activation of the PI3K pathway and loss of PTEN expression as a specific biomarker. PI3K suppression by mTORC2 inhibition synergized with dasatinib and abolished resistance in vitro and in vivo. These results provide a proof of concept for the repurposing approach in DLBCL, and point to dasatinib as an attractive strategy for further clinical development in lymphomas.


2003 ◽  
Vol 77 (3) ◽  
pp. 2134-2146 ◽  
Author(s):  
Vicky M.-H. Sung ◽  
Shigetaka Shimodaira ◽  
Alison L. Doughty ◽  
Gaston R. Picchio ◽  
Huong Can ◽  
...  

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.


Author(s):  
Eugenio Gaudio ◽  
Chiara Tarantelli ◽  
Emanuele Zucca ◽  
Davide Rossi ◽  
Anastasios Stathis ◽  
...  

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 616-616 ◽  
Author(s):  
Deepa B. Shankar ◽  
Jenny C. Chang ◽  
Bertrand Parcells ◽  
Salemiz Sandoval ◽  
Junling Li ◽  
...  

Abstract Children with acute myeloid leukemia (AML) have less than 60% overall survival despite aggressive chemotherapy and bone marrow transplantation. Only one third of the adult patients diagnosed with AML will be cured. AML blast cells from up to 30% of patients express a constitutively active receptor tyrosine kinase, FLT3-ITD, which contains an internal tandem duplication in the juxtamembrane domain. Patients with FLT3-ITD have a worse prognosis. ABT-869 is a novel multi-targeted small molecule inhibitor of receptor tyrosine kinases and is a potent inhibitor of FLT3, c-Kit, and all members of the VEGF and PDGF receptor families. To determine the effects of ABT-896 on AML cells, we treated AML cell lines, primary cells, and tumors in xenograft models with varying concentrations of the drug. In vitro viability assays showed that ABT-869 inhibited the growth of two different cell lines, MV-4-11 (human AML cell line that expresses FLT3-ITD) and BAF3-ITD (murine B-cell line stably transfected with the FLT3-ITD) at an IC50 of 10nM. ABT-869 was also effective against another mutation of FLT3, D835V, but at higher concentrations (IC50 of 100nM). Phosphorylation of FLT3 and activation of downstream signaling molecules, STAT5 and ERK, were inhibited by ABT-869 in a concentration-dependent manner. Cells were also stained with Annexin V-FITC and Propidium Iodide, and analyzed using FACS. ABT-869 induced apoptosis, caspase-3 activation, and PARP cleavage after 48 hours. To examine the in vitro effects of ABT-869 on normal hematopoietic progenitor cells, we performed methylcellulose-based colony assays with human bone marrow. No significant difference was observed in the number and type of colonies formed using BM cells treated with ABT-869 or control, up to a concentration of 1 micromolar. These results suggest that ABT-869 is not toxic to normal bone marrow progenitor cells at concentrations that are effective against AML cells. To examine the effects of ABT-869 in vivo, we treated SCID mice injected with MV-4-11, Baf3-ITD, Baf3-D835V, or Baf3-WT cells, with oral preparations of ABT-869. Complete regression of MV-4-11 tumors was observed in mice treated with ABT-869 at 20 and 40 mg/kg/day. No adverse effects were detected in the peripheral blood counts, bone marrow, spleen or liver. Histology of the tumors from the control-treated group showed a high degree of proliferation by Ki-67 staining, increased mitotic figures, and a well-defined tumor mass. In contrast, the tumors from mice treated with ABT-869 showed a number of apoptotic bodies by TUNEL staining and the presence of reactive, inflammatory cells. Interestingly, we also observed that mice that received ABT-869 the day after injection of AML cells remained tumor-free for over 2 months in contrast to the mice receiving the vehicle alone. Inhibition of FLT3 phosphorylation was demonstrated in the tumors from mice treated with ABT-869. We are evaluating the activity of ABT-869 treatment of SCID mice injected with Baf3-ITD, Baf3-D835V, or Baf3-WT cells. NOD-SCID mouse models are currently being used to analyze the effects of ABT-869 on primary AML cells in vivo. Our preclinical studies demonstrate that ABT-869 is effective and nontoxic, and provide rationale for the treatment and prevention of relapse in AML patients.


Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 1718-1718 ◽  
Author(s):  
Toshihiko Ishii ◽  
Asher Alban Chanan-Khan ◽  
Jazur Jafferjee ◽  
Noreen Ersing ◽  
Takeshi Takahashi ◽  
...  

Abstract BIW-8962 is a humanized anti-ganglioside GM2 (GM2) monoclonal antibody, produced by Poteligent technology to enhance ADCC activity. GM2 is expressed on many cancer cells including multiple myeloma (MM), small cell lung cancer and glioma cells. In this study, we evaluated the anti-myeloma activity of BIW-8962 in preclinical myeloma models both in vitro and in vivo. Expression of GM2 was analyzed in 15 human MM cell lines by FCM. Eleven out of 15 MM cell lines had positive surface expression of GM2. GM2 as a potential target was then verified in primary MM samples obtained from patients. Eleven out of 15 samples were positive for GM2. We then used two GM2 positive MM cell lines (U266B1 and KMS-11) and evaluated ADCC and CDC activity of BIW-8962 in vitro. BIW-8962 exhibited a potent ADCC and less potent CDC activity. In vivo anti-tumor activity of BIW-8962 was then examined using the standard subcutaneous xenograft model; KMS-11 was inoculated in the flank of SCID mice. BIW-8962 (intravenously administered biweekly for 3 weeks) exhibited a potent anti-tumor activity from as low a dose level as 0.1 mg/kg. Furthermore, in a more clinically relevant model, in which OPM-2/GFP (GM2 positive MM cell line) cells were intravenously inoculated into SCID mice with preferentially tumor growth within the bone marrow microenvironment, BIW-8962 (intravenously administered biweekly for 4 weeks, 10 mg/kg) suppressed OPM-2/GFP cell growth and serum M protein elevation, demonstrating in vivo anti-myeloma effect of BIW-8962. Our preclinical investigations rationalize clinical evaluation of BIW-8962 in patients with MM. Currently BIW-8962 is being investigated in a Phase 1 study in patients with multiple myeloma.


Sign in / Sign up

Export Citation Format

Share Document