MLN2238, a Novel and Potent Proteasome Inhibitor, Induces Caspase-Dependent Cell Death, Cell-Cycle Arrest, and Potentiates the Anti-Tumor Activity of Chemotherapy Agents In Rituximab-Chemotherapy Sensitive or Resistant B-Cell Lymphoma Cell Lines

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 3939-3939
Author(s):  
Juan Gu ◽  
Patil Ritesh ◽  
Cory Mavis ◽  
George Deeb ◽  
John Gibbs ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Death ◽  
B Cell ◽  
Cell Lines ◽  
Proteasome Inhibitor ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
Lymphoma Cells ◽  
Anti Tumor Activity

Abstract Abstract 3939 The use of proteasome inhibitors such as bortezomib (BTZ) has generated much excitement as a potential therapeutic approach capable of effectively treating resistant/refractory lymphoid neoplasm. Clinical outcomes in multiple myeloma and relapsed mantle cell lymphoma demonstrate that these novel agents can overcome resistance demonstrated by a lack of antitumor activity to traditional salvage chemotherapeutic agents. Our group of investigators have demonstrated that proteasome inhibition using BTZ can increase pro-apoptotic Bcl-2 family member expression and restore chemotherapy sensitivity in rituximab-chemotherapy resistant cell lines (RRCL). To further develop therapeutic strategies targeting the proteasome system, we studied the anti-tumor activity and mechanisms-of-action of MLN2238, a novel irreversible proteasome inhibitor, in pre-clinical lymphoma models. Experiments were conducted in rituximab-chemotherapy sensitive cell lines (RSCL), RRCL, and in tumor cells derived from patients with de novo or relapsed/refractory B-cell lymphoma. Cells were exposed in vitro and/or ex vivo to escalating doses of MLN2238 or BTZ (0.1-10nM) +/− caspase inhibitors (zVAD-fmk or Q-VD-OPh) for 24, 48 and 72h. Differences in mitochondrial potential and cell proliferation were determined by alamar blue reduction using a kinetic assay; changes in ATP content (apoptosis) were determined using the Cell Titer Glow assay. Effects on cell cycle were analyzed by the FASCan DNA method. In addition, lymphoma cells were exposed to MLN2238 or BTZ +/− doxorubicin, gemcitabine or paclitaxel and cell viability was evaluated as described above. In vitro, MLN2238 exhibited more potent concentration- and time-dependent cytotoxicity and inhibition of cell proliferation in RSCL, RRCL, as well as primary lymphoma cells than BTZ. In vitro exposure of RSCL and RRCL to MLN2238 potentiated the cytotoxic effects of gemcitabine, doxorubicin, and paclitaxel and overcame the acquired resistance to chemotherapy drugs in RRCL in a dose-dependent manner. Co-incubation of RSCL with bortezomib, or MLN2232 and either pan-caspase inhibitor led to a significant decrease in BTZ- or MLN2232-induced cell death. In contrast, neither zVAD-fmk nor Q-VD-OPh was capable of blocking BTZ- or MLN2232-induced cell death of RRCL. Our data suggest that BTZ and MLN2238 are also capable of inducing caspase-independent cell death in RRCL. To this regard, we found differences that RRCL are more likely to be in S phase in resting conditions when compared to RSCL. In vitro exposure of RRCL cells to MLN2232 (and to a much lesser degree BTZ) reduced RRCL S-phase and induced arrest at G2/M phase. Collectively, these data suggest that MLN2238 is a potent proteasome inhibitor active in rituximab-chemotherapy sensitive or resistant cell models and potentiates the anti-tumor activity of chemotherapy agents. MLN2232 appears to posses several mechanisms-of-action (induction of apoptosis and/or cell cycle arrest) and has the potential of becoming a novel and potent target-specific therapeutic agent in the future treatment of therapy-resistant B-cell lymphoma. (Research, in part, supported by a NIH grant R01 CA136907-01A1 awarded to Roswell Park Cancer Institute). Disclosures: No relevant conflicts of interest to declare.

Panobinostat, a Novel Histone Deacetylase (HiDAC) Inhibitor Enhances the Anti-Tumor Activity of Bortezomib (BTZ) In Rituximab-Chemotherapy Sensitive and Resistant Lymphoma Cell Lines

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 3936-3936 ◽  
Author(s):  
Francisco J. Hernandez-Ilizaliturri ◽  
Cory Mavis ◽  
Ilir Maraj ◽  
Mohammad Muhsin Chisti ◽  
John Gibbs ◽  
...  
Keyword(s):  
Western Blot ◽  
B Cell ◽  
Cell Lines ◽  
Proteasome Inhibitor ◽  
Cell Lymphoma ◽  
Single Agent ◽  
B Cell Lymphoma ◽  
Lymphoma Cells ◽  
Anti Tumor Activity

Abstract Abstract 3936 Deacetylases (DACs) are enzymes that remove the acetyl groups from target proteins [histones (class I) and non-histone proteins (class II)], leading to regulation of gene transcription and other cellular processes. Panobinostat (LBH589) is a novel and potent DAC class I and II inhibitor undergoing pre-clinical and clinical testing. In order to better characterize the role of DAC inhibitors in the treatment of refractory/resistant B-cell lymphoma., We studied the anti-tumor activity of panobinostat as a single agent or in combination with the proteasome inhibitor (BTZ) against a panel of rituximab-[chemotherapy]-sensitive cell lines (RSCL), rituximab-[chemotherapy]-resistant cell lines (RRCL), and primary lymphoma cells isolated from patients with treatment-naïve or refractory/relapsed B-cell lymphoma. In addition, we characterized the mechanisms responsible for panobinostat anti-tumor activity. Non-Hodgkin lymphoma (NHL) cell lines were exposed to escalating doses of panobinostat (0.5-5nM) +/− BTZ (1-5nM). Changes in mitochondrial potential and ATP synthesis were determined by alamar blue reduction and cell titer glo luminescent assays, respectively. Subsequently, protein lysates were isolated from panobinostat +/− BTZ exposed cells and changes in members of Bcl-2 family proteins were evaluated by Western blot. Finally, to characterize panobinostat's mechanisms-of-action, lymphoma cells were exposed to panobinostat with or without pan-caspase (Q-VD-OPh, 5mM) or autophagy (3-methyladenine [3MA] 5mM) inhibitors and changes in cell viability were detected as above. Optimal experimental conditions were confirmed by Western blot. Panobinostat exhibited dose-dependent activity as a single agent against RSCL, RRCL and patient-derived primary tumor cells (N=25). In addition, synergistic activity was observed by combining panobinostat with BTZ in vitro. The pharmacological interactions between panobinostat and proteasome inhibitor could be explained in part by the effects each agent has on the expression levels of Bcl-2 family members. In vitro exposure of lymphoma cells to panobinostat resulted in Bcl-XL down-regulation, whereas BTZ exposure causes up-regulation of Bak and Noxa and downregulation of Mcl-1 and Bcl-XL. Caspase inhibition diminished panobinostat anti-tumor activity in RSCL but not in RRCL. On the other hand, exposure of RRCL to 3MA, significantly inhibited the anti-tumor activity of panobinostat in RRCL. Together this data suggest that, panobinostat has a dual mechanism-of-action and can induce cell death by caspase-dependent and -independent pathways. Our data suggests that panobinostat as a single agent is active against rituximab-chemotherapy sensitive and resistant lymphoma cells and potentiates the anti-tumor activity of a proteasome inhibitor (BTZ). A better understanding in the molecular events (caspase-dependent and -independent) triggered by panobinostat in combination with proteasome inhibition is important in order to develop optimal combination strategies using these exciting agents in future clinical trials. (Research, in part, supported by a NIH grant R01 CA136907-01A1 awarded to Roswell Park Cancer Institute) Disclosures: No relevant conflicts of interest to declare.

Carfilzomib (CFZ): A Novel Proteasome Inhibitor That Induces Cell Cycle Arrest and Cell Death In Rituximab-Chemotherapy Resistant Lymphoma and Potentiates the Anti-Tumor Activity of Chemotherapeutic Agents

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 4908-4908
Author(s):  
Juan Gu ◽  
Francisco J. Hernandez-Ilizaliturri ◽  
Gregory P. Kaufman ◽  
Cory Mavis ◽  
Myron S. Czuczman
Keyword(s):  
Cell Cycle ◽  
B Cell ◽  
Cell Cycle Arrest ◽  
Cell Lines ◽  
Proteasome Inhibitor ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
Parp Cleavage ◽  
Cycle Arrest ◽  
Anti Tumor Activity

Abstract Abstract 4908 Rituximab-chemotherapy relapsed/refractory B-cell lymphomas represent an emerging clinical challenge that underlies the need to develop alternative therapeutic strategies. Targeting the ubiquitin-proteasome system using bortezomib (BTZ) has resulted in significant anti-tumor activity and potentiates the effects of chemotherapy/biologic agents in multiple myeloma, and to a lesser degree, B-cell lymphoma. CFZ is as a novel proteasome inhibitor which is selective and structurally distinct from BTZ. In an attempt to characterize the biological activity of CFZ, we evaluated its anti-tumor activity in several lymphoma pre-clinical models. Rituximab-chemotherapy sensitive cell lines (RSCL), rituximab-chemotherapy resistant cell lines (RRCL), as well as primary tumor cells derived from patients with de novo or relapsed/refractory B-cell lymphoma, were exposed to escalating doses of CFZ or BTZ (1-7.5nM) alone or in combination with doxorubicin, paclitaxel, or gemcitabine for 24, 48 and 72hours. Cell viability was determined by cell titer glow luminescent assay and cell cycle was analyzed by FASCan DNA methodology. Patient-derived lymphoma cells were isolated from fresh biopsy tissue via negative selection using magnetic beads. Western blots were performed using cell lysates from CFZ, BTZ or control-treated cells to detect PARP-cleavage and/or changes in Bcl-2 family members. CFZ was more active than BTZ and exhibited dose-dependent and time-dependent cytotoxicity against RSCL, RRCL, and primary tumor cells. We found a 10-fold concentration difference between CFZ and BTZ activity. In vitro exposure of RRCL or RSCL to CFZ resulted in G2/M phase cell cycle arrest. In addition, CFZ exposure resulted in the up-regulation of Bak and Noxa levels and subsequent PARP cleavage in RRCL. Finally, CFZ demonstrated the ability to overcome resistance to chemotherapy in RRCL and potentiated the anti-tumor activity of paclitaxel and gemcitabine in B-cell lymphoma cell lines. In summary, our data strongly suggest that CFZ is a novel and potent proteasome inhibitor which is able to: overcome resistance to some conventional chemotherapeutic agents, upregulate proapoptotic proteins to enhance cell death, and induce G2/M cell cycle arrest in lymphoma cells. Our preclinical data supports future clinical evaluation of CFZ in patients with refractory B-cell lymphoma. (Supported by USPHS grant R01 CA136907-01A1 from the National Cancer Institute). Disclosures: No relevant conflicts of interest to declare.

Entinostat, a Novel Histone Deacetylase (HiDAC) Inhibitor Enhances the Anti-Tumor Activity of Bortezomib (BTZ) in Rituximab-Chemotherapy Sensitive and Resistant Lymphoma Cell Lines,

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3734-3734
Author(s):  
Cory Mavis ◽  
Sarah Frys ◽  
Juan Gu ◽  
John Gibbs ◽  
Myron S. Czuczman ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Lines ◽  
Research Funding ◽  
Cell Lymphoma ◽  
Single Agent ◽  
B Cell Lymphoma ◽  
Lymphoma Cells ◽  
In Vitro Exposure ◽  
Anti Tumor Activity

Abstract Abstract 3734 Deacetylases (DACs) are enzymes that remove the acetyl groups from target proteins [histones (class I) and non-histone proteins (class II)], leading to regulation of gene transcription and other cellular processes. Entinostat (MS-275) is a novel and potent DAC class I inhibitor undergoing pre-clinical and clinical testing. In order to better characterize the role of DAC inhibitors in the treatment of refractory/resistant (r/r) B-cell lymphoma, we studied the anti-tumor activity of entinostat as a single agent or in combination with the proteasome inhibitor bortezomib (BTZ) against a panel of rituximab-[chemotherapy]-sensitive cell lines (RSCL), rituximab-[chemotherapy]-resistant cell lines (RRCL), and primary lymphoma cells isolated from patients with treatment-naïve or r/r B-cell lymphoma. In addition, we characterized the mechanisms responsible for entinostat's anti-tumor activity. Non-Hodgkin lymphoma (NHL) cell lines were exposed to escalating doses of entinostat (0.1 to 20uM) +/− BTZ (1–10nM). Changes in mitochondrial potential and ATP synthesis were determined by alamar blue reduction and cell titer glo luminescent assays, respectively. Changes in cell cycle were determined by flow cytometric analysis. Subsequently, protein lysates were isolated from entinostat +/− BTZ exposed cells and changes in members of Bcl-2 and cell cycle family proteins were evaluated by Western blotting. Finally, to characterize entinostat's mechanisms-of-action, lymphoma cells were exposed to entinostat with or without pan-caspase (Q-VD-OPh, 5mM) and changes in cell viability were detected. Entinostat exhibited dose-dependent activity as a single agent against RSCL, RRCL and patient-derived primary tumor cells (N=32). In addition, in vitro exposure of lymphoma cells to entinostat resulted in an increase in G1 and a decrease in S phase. Moreover synergistic activity was observed by combining entinostat with BTZ in vitro. The pharmacological interactions between entinostat and proteasome inhibitor could be explained in part by each agent's effects on the expression levels of cell cycle proteins. In vitro exposure of lymphoma cells to entinostat resulted in p21 upregulation and p53 down-regulation, whereas BTZ exposure lead to up-regulation of Bak and Noxa and downregulation of Mcl-1 and Bcl-XL. Caspase inhibition diminished entinostat anti-tumor activity in RSCL but not in RRCL. Together this data suggests that entinostat has a dual mechanism-of-action and can induce cell death by caspase-dependent and independent pathways. Our data suggests that entinostat as a single agent is active against rituximab-chemotherapy sensitive and resistant lymphoma cells and potentiates the anti-tumor activity of BTZ. A better understanding in the molecular events (caspase-dependent and -independent) triggered by entinostat in combination with proteasome inhibition is important in order to develop optimal combination strategies using these novel agents in future clinical trials. Disclosures: Czuczman: Millennium: Honoraria, Research Funding. Hernandez-Ilizaliturri:Genmab: Research Funding; Amgen: Research Funding; Celgene: Consultancy.

The Novel Proteasome Inhibitor Carfilzomib (CFZ) Potentiates the Anti-Tumor Activity of Chemotherapeutic Agents in Rituximab-Chemotherapy Resistant Lymphoma Through Inducing G2/M Cell Cycle Arrest and Cell Death

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 4970-4970
Author(s):  
Juan Gu ◽  
Natalie M Czuczman ◽  
Gregory P. Kaufman ◽  
Cory Mavis ◽  
Francisco J. Hernandez-Ilizaliturri ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Death ◽  
B Cell ◽  
Tumor Cells ◽  
Primary Tumor ◽  
Proteasome Inhibitor ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
M Cell ◽  
Anti Tumor Activity

Abstract Abstract 4970 The concept of proteasome inhibition (PI) is an attractive therapeutic approach for resistant/refractory lymphoma. While bortezomib has modest activity against certain types of lymphomas, a significant number of patients develop resistance or experience dose-limiting toxicity. Carfilzomib (CFZ), a novel second-generation irreversible proteasome inhibitor, has demonstrated significant and well-tolerated anti-tumor activity in relapsed/refractory (r/r) myeloma patients. Here we evaluated CFZ's mechanism(s)-of-action and anti-tumor activity in several lymphoma pre-clinical models. Rituximab-chemotherapy sensitive cell lines (RSCL), rituximab-chemotherapy resistant cell lines (RRCL), as well as primary tumor cells (n=25) were exposed in vitro and/or ex vivo to escalating doses of CFZ or BTZ (0.1-10nM) +/− caspase inhibitors (zVAD-fmk or Q-VD-OPh) for 24, 48 and 72hrs. Changes in ATP content (apoptosis) were determined using the Cell Titer Glow assay and in cell cycle were analyzed by FACScan DNA methodology. Patient-derived lymphoma cells were isolated from fresh biopsy tissue via negative selection using magnetic beads. Western blots were performed using cell lysates from control versus treated (i.e. CFZ or BTZ) cells to detect PARP-cleavage and changes in Bcl-2 family members or cell cycle regulators. CFZ was found to be 10 times more potent than BTZ and exhibited dose- and time- dependent cytotoxicity against RSCL, RRCL, and primary tumor cells. CFZ has potent anti-tumor activity in tumor cells derived from patients with follicular lymphoma (FL), diffuse large B-cell lymphoma (DLBCL), Hodgkin lymphoma (HL) and other histologies. CFZ exposure induced apoptosis by up-regulation of Bak, Mcl-1 levels and subsequent PARP cleavage in RSCL and (to a lesser degree) RRCL. Co-incubation of RSCL with either BTZ or CFZ and pan-caspase inhibitor led to a significant decrease in BTZ- or CFZ-induced cell death. In contrast, zVAD-fmk and Q-VD-OPh were associated with only partial blocking of BTZ- or CFZ-induced cell death of RRCL. In addition, In vitro exposure of RRCL cells to CFZ (and to a much lesser degree BTZ) reduced RRCL S-phase and induced arrest at G2/M phase. CFZ stabilized G2/M cell cycle regulators cdc2 and cyclinB only in RRCL. Finally, CFZ demonstrated the ability to overcome resistance to chemotherapy in RRCL and potentiated the anti-tumor activity of paclitaxel and vincristine in B-cell lymphoma cell lines and in primary tumor samples. In summary, our data strongly suggest that CFZ is a novel and potent proteasome inhibitor which is has the potential to: overcome resistance to some conventional chemotherapeutic agents, upregulate proapoptotic proteins to enhance cell death, and induce G2/M cell cycle arrest in lymphoma cells. Our preclinical data supports future clinical evaluation of CFZ in patients with refractory B-cell lymphoma. Research, supported in part as a subproject of NIH grant R01 CA136907-01A1 awarded to Roswell Park Cancer Institute. Disclosures: Hernandez-Ilizaliturri: Genmab: Research Funding; Amgen: Research Funding; Celgene: Consultancy. Czuczman:onyx: Consultancy, Honoraria.

Evaluation of the Anti-Tumor Activity of MLN4924, A Novel NEDD8 Activating Enzyme Inhibitor, in Pre-Clinical Models of Rituximab Chemotherapy-Sensitive or -Resistant B-Cell Lymphoma.

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 2761-2761
Author(s):  
Natalie M Czuczman ◽  
Matthew J. Barth ◽  
Richa Dwar ◽  
Cory Mavis ◽  
Pavel Klener ◽  
...  
Keyword(s):  
Cell Cycle ◽  
B Cell ◽  
Cell Lines ◽  
Cell Lymphoma ◽  
Single Agent ◽  
B Cell Lymphoma ◽  
Lymphoma Cells ◽  
Clinical Models ◽  
Chemotherapy Agents ◽  
Anti Tumor Activity

Abstract Abstract 2761 Clinical outcome of patients with relapsed/refractory diffuse large B-cell lymphoma (DLBCL) and mantle cell lymphoma (MCL) remains poor with currently available therapies. Recently, the ubiquitin-proteasome system (UPS) appears to play an important role in the development of resistance in MCL and some subtypes of DLBCL. Targeting UPS represents a rational approach in an attempt to eradicate drug-resistant lymphoma clones. MLN4924 is a novel, potent and selective inhibitor of the NEDD8-activating enzyme (NAE) that is necessary for the modification of cullin-RING ubiquitin ligases. We evaluated the anti-tumor activity of MLN4924 against a panel of rituximab-sensitive (RSCL) or rituximab/chemotherapy–resistant (RCRCL) DLBCL and Burkitt lymphoma cell lines, cytarabine-sensitive or -resistant (AraCR) MCL cell lines, and primary tumor cells freshly isolated from lymphoma patients (n=13). Lymphoma cells were exposed to escalating doses of MLN4924 alone or in combination with selected chemotherapy agents for up to 72 hrs. Changes in the cell viability or ATP content were determined by alamar Blue reduction or CellTiterGlo assays, respectively. Induction of apoptosis and changes in the levels of NFkB and UPS regulatory proteins were analyzed by Western blotting. Cell cycle alterations were determined by propidium iodide staining and NFkB activity was quantified by flow cytometry using the Imagestream technology. MLN4924 demonstrated time- and dose-dependent anti-lymphoma activity in all cell lines tested. The IC50 in RSCLs were Raji=400nM, RL=1uM and U2932=>3uM. All RCRCLs were less responsive to MLN4924 as a single agent with IC50 concentrations 4–10× those of their respective sensitive parental cell lines. The MCL cell lines Mino, MinoAraCR, Z-138, HBL-2 and HBL-2AraCR were most sensitive to MLN4924 anti-tumor effects (IC50=250nM) with no significant difference between cytarabine-sensitive and -resistant cell lines; while the MCL cell lines Rec-1, Rec-1AraCR, Jeko-1 and Jeko-1AraCR were less sensitive (IC50=500–1000nM). A variable degree of anti-tumor activity was also observed in primary lymphoma cells. In addition to single-agent activity, MLN4924 plus selected anti-lymphoma chemotherapy agents (bortezomib, bendamustine and cytarabine) demonstrated synergy in cytarabine-sensitive and (to a lesser degree) cytarabine-resistant MCL cell lines. Combinations with additional chemotherapeutic agents (doxorubicin and vincristine) resulted in additive effects. Exposure of MCL cells to MLN4924 resulted in G1 cell cycle arrest. In vitro exposure of the more sensitive MCL cell lines Mino and MinoAraCR to MLN4924 resulted in an increase in p-IkBα and down-regulation of both total and nuclear NFkB. The less sensitive cell lines Rec-1 and Rec-1AraCR demonstrated little to no change in NFkB activation following exposure to MLN4924. Additional studies are ongoing to further define the molecular mechanisms of the anti-tumor activity observed following NAE inhibition by MLN4924 in these pre-clinical models and to further evaluate the activity of MLN4924 in in vivo SCID mouse models of B-cell lymphoma. Our data suggests that MLN4924, a novel NAE inhibitor, is active against B-cell lymphomas, particularly MCL, and is a promising agent warranting further investigation in relapsed/refractory aggressive B-cell lymphomas. Disclosures: No relevant conflicts of interest to declare.

The Green Tea Extract Epigallocatechin Induces In Vitro Cell Death in Primary Human Lymphoma Cells through an ROS Dependent Mechanism.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 234-234 ◽  
Author(s):  
Tait D. Shanafelt ◽  
Yean K. Lee ◽  
Susan M. Geyer ◽  
Deanna Grote ◽  
Mary Stenson ◽  
...  
Keyword(s):  
Cell Death ◽  
B Cell ◽  
Cell Lines ◽  
Green Tea ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
Lymphoma Cell ◽  
Primary Lymphoma ◽  
Lymphoma Cells

Abstract BACKGROUND: We have demonstrated the green tea extract epigallocatechin-3-gallate (EGCG) has anticancer activity in primary CLL B-cells (Lee, Blood 2004). After dissemination of our in vitro findings by the lay press, many patients with CLL and other low grade non-Hodgkin lymphomas (NHL) began using over the counter green tea extracts as an alternative treatment strategy. We recently reported a case series of 3 patients with CLL and 1 patient with follicular lymphoma who appeared to derive objective clinical benefit from such treatment (Shanafelt, Leukemia Research 2006). Based on these findings EGCG has entered clinical testing for treatment of CLL at Mayo Clinic. Here we explore the in vitro antitumor activity of EGCG against other types of non-Hodgkin lymphoma. METHODS: Five established human B-cell lymphoma cell lines (HT, DOHH2, KARPAS, Ramos, RL) and primary lymphoma cells from 7 patients with various B-cell NHL sub-types [DLBC, FL, SMZ (2), MCL, SLL(2)] were used to evaluate the in vitro sensitivity of human lymphoma cells to EGCG. Freshly isolated primary lymphoma cells harvested in suspension from lymph nodes/spleen were obtained from patients with NHL who provided written informed consent. All patients were untreated at the time of biopsy. Lymphoma cell lines and primary lymphoma cells (n=7) were cultured with increasing doses of purified EGCG (3.12–50 ug/ml) for 24–72 hrs. Viability was assessed by using annexin/PI staining by FACS analysis. RESULTS: EGCG-induced dose dependent cell death in both established human B-cell lymphoma cell lines (average LD50 at 24 hrs between 25–50 ug/mL) and primary NHL cells (average LD50 at 24 hrs between 25–50ug/mL). In contrast, EGCG had minimal effect on purified normal B-cells (n=3) at the highest doses tested (50 ug/mL). By immunoblotting, EGCG-induced death in primary cells and cell lines was associated with PARP cleavage, suggesting the agent induced apoptotic cell death. Despite this finding, EGCG had no effect on levels of MCL-1, XIAP, or Bcl-1 by either immunoblot or FACS analysis. Based on reports that EGCG induces cell death in some cancer cell types through generation of oxidative stress (Furukawa, 2003; Nakazato, 2005), we explored this mechanism in lymphoma cells. To determine whether reactive oxygen species (ROS) generation was necessary for EGCG-induced cell death, lymphoma cell lines were cultured with or without catalase (which catalyzes the conversion of hydrogen peroxide to water and oxygen) for 30 min prior to subsequent 24 hr EGCG exposure (50 and 100 mg/ml). Pre-treatment with catalase (100 U) provided dramatic protection against cell death in both primary NHL cells and NHL cell lines suggesting that EGCG-induced cell death in lymphoma cells is dependent on ROS generation (Fig. 1 shows an example for a patient with mantle cell lymphoma and a patient with splenic marginal zone lymphoma). CONCLUSION: EGCG has in vitro anti-tumor activity against a variety of B-cell NHLs. Given its known favorable toxicity profile in vivo, EGCG is an attractive agent for clinical testing in patients with indolent NHL who otherwise are currently being managed with observation. Figure Figure

Z-Guggulsterone Downregulates Survivin and Induces Cell Death in Large B Cell Lymphoma Cells In Vitro.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 4752-4752
Author(s):  
Maria K. Angelopoulou ◽  
Konstantinos Lilakos ◽  
Vassilios Salpeas ◽  
Sotirios Sachanas ◽  
Penelope Korkolopoulou ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Cell Death ◽  
Cell Viability ◽  
B Cell ◽  
Cell Lines ◽  
Cell Lymphoma ◽  
Survivin Expression ◽  
B Cell Lymphoma ◽  
Lymphoma Cells

Abstract Introduction: Survivin is a member of the Inhibitor of Apoptosis Proteins and has recently gained attention as a possible therapeutic target in malignancies, due to its dual role both as an antiapoptotic protein and as a cell cycle regulator. It is overexpressed in malignant cells and confers resistance to chemotherapy and other stimuli triggering apoptosis. Z-Guggulsterone (Z-GGS) is a plant sterol, which has been used in inflammatory conditions and has been recognized as a potent NF-kB suppressor. Since Survivin, as well as other antiapoptotic proteins, are under NFkB regulation, we studied the effect of Z-GGS on two B-cell lymphoma cell lines. Methods: DB and HT cell lines were treated with increasing concentrations (10μM, 20μM and 30μM) of Z-GGS, for 24, 48 and 72 hours. Survivin expression was tested with Flow Cytometry and Survivin transcripts were measured with quantitative real time PCR using the Universal Probe Library hydrolysis probes and expressed as Survivin/abl ratio. Cell viability was assessed with the MTT assay. Results: Both cell lines were positive for Survivin at baseline by flow cytometry (66% of total cells for DB and 95% for HT). Treatment of DB cells with 10, 20 and 30μM Z-GGS resulted in a 44%, 49% and 68% reduction of Survivin expression at 24 hours, respectively, whereas the effect on HT was less prominent with a 10% reduction at 24 hours with 30μM Z-GGS. Survivin transcripts decreased as well, with the maximum effect observed at 72 hours with 30μM Z-GGS for both cell lines: Survivin/abl was 0.009 for untreated cells vs 0.0008 with 30μM Z-GGS for DB cells and 0.0135 vs 0.0005 for HT cells. Linearity was observed for increasing concentrations of Z-GGS at 72 hours. Cell viability was practically unaffected at any time point with 10 and 20μM Z-GGS for both cell lines, whereas 30 μM Z-GGS resulted in a 63% and 78% cell death at 48 and 72 hours respectively for DB cells and 67% and 83% for HT cells. Conclusions: The steroid Z-GGS downregulates Survivin expression in B-lymphoma cells in vitro and induces cell death at 30μM concentration. Further experiments will clarify its possible role in the treatment of B-cell malignancies.

Apoptotic and Non-Apoptotic Cellular Pathways Executed by Bortezomib (BTZ) in Rituximab-Resistant Lymphomas

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 4967-4967
Author(s):  
Juan Gu ◽  
Francisco J. Hernandez-Ilizaliturri ◽  
Cory Mavis ◽  
Natalie M Czuczman ◽  
Karen E Thudium ◽  
...  
Keyword(s):  
Cell Cycle ◽  
B Cell ◽  
Tumor Cells ◽  
Research Funding ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
Mitotic Catastrophe ◽  
M Cell ◽  
Lymphoma Cells

Abstract Abstract 4967 Rituximab-chemotherapy relapsed/refractory (r/r) B-cell lymphomas represent an emerging clinical challenge that underlies the need to develop alternative therapeutic strategies. A better understanding of the mechanism(s)-of-action of BTZ and other proteasome inhibitors (PI) is likely to aid in the identification of biomarkers that can be used to determine clinical responsiveness and/or help in the rational development of novel PI-based therapeutic combinations (e.g. incorporating biologics, small molecules and/or chemotherapy) in r/r B-cell lymphoma. Previously we demonstrated that rituximab resistance was associated with increased proteasome activity leading to a de-regulation in the apoptotic threshold of lymphoma cells to multiple chemotherapy agents. Pharmacological and genetic (e.g. siRNA silencing of BAK/BAX) inhibition of apoptosis partially affected BTZ activity in rituximab-resistant (RSCL) but not in rituximab-sensitive cell lines (RSCL) suggesting the existence of alternative pathways of cell death associated with PI exposure. To this end we evaluated the contribution of cellular senescence, cell cycle inhibition, or mitotic catastrophe to the anti-tumor activity of BTZ as a single agent or in combination with chemotherapeutic agents in RSCL, RRCL and in primary tumor cells. Lymphoma cells were exposed to BTZ (10-25nM) for 24–48 hrs. Cell senescence was determined by SA-β-gal staining using a senescence assay kit and inverted phase-contrast microscopy was performed. Changes in cell cycle were analyzed by the FACScan DNA method and changes in cell cycle regulatory proteins (i.e. cdc2, cyclinA/B, p21, CDK2/4/6) were analyzed by Western blotting. Mitotic index was determined by Wright-Giemsa stain and positive cells were counted under a Nikon microscope. Mitotic catastrophe was determined by confocal microscopy by staining with α-tubulin antibody. Finally, changes in ATP content was determined by the Cell Titer Glo assay. Baseline differences were observed between RSCL and RRCL in terms of cell morphology, proliferation rate and senescence. RRCL (Raji2R and Raji4RH) were considerably larger in size, had a slower proliferation rate and an exhibited a 3-fold increase the number of cells in senescence than RSCL. In vitro exposure of RSCL and RRCL to BTZ attenuated the number of cells in senescence by 50–75%. Cell cycle analysis demonstrated that RRCL had more cells in S phase when compared to RSCL. In vitro exposure to BTZ-induced G2/M arrest in RRCL, but not in RSCL. Overexpression of G2/M cell cycle regulatory proteins cyclin B and cdc2 were observed in RRCL and in tumor cells isolated from r/r B-cell lymphoma patients. Mitotic catastrophe with multi-nucleated cells were only detected in RRCLs exposed to BTZ. In vitro and ex vivo exposure of RSCL and RRCL to BTZ potentiated the cytotoxic effects of paclitaxel and overcame the acquired resistance to chemotherapy drugs in RRCL and primary tumor cells isolated from r/r lymphoma patients in a dose-dependent manner. Our results suggested that BTZ activates several death pathways in B-cell lymphoma pre-clinical models. In addition to apoptosis, BTZ is capable in triggering mitotic catastrophe in rituximab-chemotherapy lymphoma cells with decreased levels of pro-apoptotic proteins. Moreover, sensitization of RRCL to drug therapy involves interplay between cellular senescence attenuation, G2/M cell cycle regulation, and mitotic catastrophe. Hence, proteasome inhibition may provide a novel therapeutic approach for treating apoptosis-resistant B-cell lymphoma. Research, supported in part as a subproject of NIH grant R01 CA136907-01A1 awarded to Roswell Park Cancer Institute. Disclosures: Hernandez-Ilizaliturri: Genmab: Research Funding; Amgen: Research Funding; Celgene: Consultancy. Czuczman:Millennium: Honoraria, Research Funding.

JQ1, a Potent c-MYC Inhibitor Overcomes Rituximab-Chemotherapy Resistance in Lymphoma Pre-Clinical Models

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 2761-2761
Author(s):  
Juan J Gu ◽  
Qunling Zhang ◽  
Cory Mavis ◽  
Myron S. Czuczman ◽  
Francisco J. Hernandez-Ilizaliturri
Keyword(s):  
Cell Cycle ◽  
Cell Death ◽  
B Cell ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
Advisory Board ◽  
Synergistic Activity ◽  
Targeted Agents ◽  
Chemotherapy Agents

Abstract Background: The poor clinical outcomes of patients with aggressive B-cell lymphoma in the post-rituximab era, stress the need to identify and/or optimize novel targeted agents. Several retrospective and prospective clinical studies had demonstrated that C-myc expression correlates with a poor clinical outcome in patients with newly diagnosed or relapsed/refractory diffuse large B-cell lymphoma (DLBCL). To this end, we evaluated the therapeutic effects of targeting C-myc using JQ1, a novel bromodomain inhibitor in rituximab-sensitive or -resistant models. Methods: A panel of rituximab-sensitive (RSCL) or rituximab-resistant (RSCL) cell lines was exposed to JQ1 (0-100 µM) for 24-72 hrs. Changes in cell viability and cell cycle distribution were evaluated using the Presto Blue assay and flow cytometry respectively. IC50 values were calculated using the GraphPad Prism6 software. Subsequently lymphoma cells were exposed to JQ1 or vehicle and various chemotherapy agents such as doxorubicin (0.5, 1, 2µM), dexamethasone (1µM), Ibrutinib (1µM), bortezomib (10-20nM) or carfilzomib (10nM) for 48 hours. Coefficient of synergy was calculated using the CalcuSyn software. Results: In vitro exposure of RRCL and to a lesser degree RSCL to JQ1 resulted in a dose- and time-dependent cell death. Strong synergistic activity was observed when JQ1 was combined with doxorubicin, dexamethasone bortezomib or carfilzomib in vitro. Cell cycle analysis demonstrated that in vitro of RSCL or RRCL to JQ1 resulted in G1 cell cycle arrest. Conclusions: In summary, our data suggests that targeting C-myc expression using JQ1 results in anti-tumor activity against RSCL and RRCL. In addition, JQ1 exhibited synergistic activity when combined with chemotherapy agents (doxorubicin or dexamethasone) or targeted agents (bortezomib or carfilzomib). On going studies are aimed to study the mechanisms by which c-myc inhibition results in cell death in RSCL and RRCL. JQ1 is a distinct targeted agent undergoing clinical evaluation in patients with relapsed/refractory lymphomas. Molecular studies dissecting the cellular pathways affected by JQ1 are important in order to further advance the clinical development of c-myc inhibitors in lymphoid malignancies. (Research, in part, supported by a NIH grant R01 CA136907-01A1 awarded to Roswell Park Cancer Institute and The Eugene and Connie Corasanti Lymphoma Research Fund) Disclosures Czuczman: Boehringer-Ingelheim: Other: Advisory Board; Immunogen: Other: Advisory board; MorphoSys: Consultancy; Celgene: Employment.

Obatoclax and Bortezomib Therapy Results in Disruption of the p53-Mediated Apoptosis/Autophagy Pathway and Is Associated with Potent Synergistic Anti-Tumor Activity against Rituximab-Chemotherapy-Sensitive and -Resistant B-Cell Lymphoma.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 288-288 ◽  
Author(s):  
Francisco Hernandez-Ilizaliturri ◽  
Ping-Chiao Tsio ◽  
Ryan Campagna ◽  
Cory Marvis ◽  
Wasif Riaz ◽  
...  
Keyword(s):  
Cell Death ◽  
B Cell ◽  
Tumor Cells ◽  
Primary Tumor ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
Synergistic Activity ◽  
Knock Down ◽  
Anti Tumor Activity

Abstract Abstract 288 Interaction between the members of the BH3 domain family of proteins plays an important role in the development, progression, and prognosis of various subtypes of B-cell lymphoma. Therapies that selectively induce a pro-apoptotic environment are an attractive strategy to overcome chemotherapy-resistance in B-cell lymphoma. The proteasome is an important regulator of various members of Bcl-2 family proteins. We previously demonstrated that obatoclax, a novel BH3 mimetic, was able to enhance the anti-tumor activity of rituximab and chemotherapy agents and induced both apoptosis and autophagy in B-cell lymphoma. In an attempt to increase the therapeutic options for B-cell lymphoma patients we studied the biological effects of obatoclax in combination with bortezomib in a panel of rituximab-[chemotherapy]-sensitive (RSCL) and rituximab-[chemotherapy]-resistant cell lines (RRCL), as well as primary tumor cells isolated from 45 NHL patient biopsy samples with various subtypes of B-cell lymphoma: (ie including, DLBCL, follicular lymphoma (FL), marginal zone lymphoma (MZL), mantle cell lymphoma (MCL), and Hodgkin lymphoma (HL)]. Patient-derived primary tumor cells were isolated from fresh biopsies by negative selection using magnetic beads. Transient knock-down of p53 and Noxa were performed to determine the role of p53 in the anti-tumor activity of bortezomib or obatoclax, respectively. NHL cells were exposed in vitro to escalating doses of obataclox (0, 2, 5, 10 and 20mM) and/or bortezomib (0, 2, 10 and 20nM) for 24 and 48 hrs. Cell death was determined by the cell glow luminescent assay and DNA synthesis was evaluated by standard [3H]-Thymidine incorporation assays at 24 and 48 hrs. Changes in mitochondrial potential and cell proliferation were determined by alamar blue reduction using a kinetic assay measuring activity at 4 hr intervals for 24 and 48 hrs. In vitro exposure of RRCL, RSCL, and primary tumor cells to the combination of obatoclax plus bortezomib demonstrated significant synergistic activity compared to controls. Patients with DLBCL (n=15) and FL (N=12) demonstrated significant sensitivity to this combination. Of note, activity was observed in patients with either de novo or relapsed/refractory germinal B-cell (GBC) or activated B-cell (ABC) DLBCL (as characterized by the Han's criteria). Additionally, cell death induced by obatoclax or bortezomib could be inhibited by transient knock-down of p53 or Noxa, respectively. In summary, deregulation of apoptosis by BH3 inhibition with obatoclax and bortezomib results in cell death and antiproliferation not only in RSCL and RRCL, but also in primary tumor cells derived from “treatment-naïve or refractory” DLBCL and FL patients. Data strongly suggests that both p53 and Noxa have pivotal roles in response to obatoclax and bortezomib. The combination of obatoclax plus bortezomib has the potential of becoming a novel and potent therapeutic strategy in the treatment of B-cell lymphoma in the future. Research, in part, supported as part of a subproject on NIH PO1 grant CA103985-1 awarded to the Garden State Cancer Center, Belleville, NJ and NHI R-01 grant R01 CA136907-01A1 awarded to Roswell Park Cancer Institute Disclosures: No relevant conflicts of interest to declare.

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