Validation of the Function of 14-3-3 ζ in Multiple Myeloma (MM)

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 1369-1369
Author(s):  
Yanyan Gu ◽  
Jonathan L. Kaufman ◽  
Lawrence H. Boise ◽  
Sagar Lonial
Keyword(s):  
Cell Cycle ◽  
Multiple Myeloma ◽  
Signaling Pathways ◽  
Cell Lines ◽  
Research Funding ◽  
Drug Sensitivity ◽  
Stable Cell Lines ◽  
Induced Apoptosis ◽  
The Impact

Abstract Abstract 1369 The 14-3-3 protein family includes seven members, β, γ, ε, η, σ, τ and ζ. With over 200 binding partners, 14-3-3 proteins act as integrators of diverse cell signaling pathways and participate in metabolism, cell cycle regulation, survival and apoptosis. 14-3-3ζ has been implicated in many cancers such as hepatocellular carcinoma, gastric cancer, breast cancer, lung carcinoma and lymphoma. However, the role of 14-3-3ζ in MM has not been extensively explored. Preliminary data from an affymatrix GEP profile of normal plasma cells (NPC), MGUS, Smoldering myeloma (SM) or multiple myeloma (MM) demonstrates statistically increased expression of 14-3-3 ζ in the transition between MGUS and SM. Among patients with newly diagnosed symptomatic MM, 14-3-3 ζ expression appears to be higher in the higher risk genetic subsets. These data suggest 14-3-3ζ plays a prominent role in the biology of MM especially among high risk myeloma patients. In order to identify the impact of 14-3-3 ζ signaling on MM proliferation and survival, we developed 14-3-3ζ silenced and over expressing stable cell lines to interrogate the biological role of 14-3-3ζ in MM. Using a library of human MM cell lines, we found that 14-3-3ζ is universally expressed in all MM cell lines examined. Knockdown of 14-3-3ζ significantly inhibits cell growth and proliferation in LP1 and U266 cells, which is partly related to G1 cell cycle arrest. Relevant signaling proteins such as Mcl-1, Bcl2, phospho-Akt and CDK6 decrease after silencing 14-3-3ζ. Furthermore, we performed gene expression profiling of LP1 scrambled and knockdown stable cell lines in order to identify key changes in gene regulation that may be mediated via 14-3-3ζ. The GEP data suggests that 14-3-3ζ is responsible for but not limited to several important signaling pathways, such as glycolysis/gluconeogenesis, p53 Signaling, NRF2-mediated oxidative stress response and death receptor signaling. In addition, we evaluated the effect of 14-3-3ζ expression on the drug sensitivity to commonly used chemotherapeutic compounds in MM treatment, such as bortezomib, etoposide, dexamethasone, melphalan, lenalidomide, doxorubicin and romidepsin. Knockdown 14-3-3ζ sensitizes cells to romidepsin- induced apoptosis, as demonstrated by Annexin V staining and western blot assay for caspase cleavage. However, bortezomib- induced apoptosis is significantly inhibited when 14-3-3ζ is silenced. Bortezomib (5nM)-induced apoptosis decreased from 37% in LP1 cells expressing shRNA with scrambled sequence to 14% in LP1 cells where 14-3-3 ζ is silenced. Moreover, 14-3-3ζ knockdown effectively inhibits bortezomib induced NOXA upregulation, suggesting a possible new molecular mechanism for the effects of 14-3-3ζ in bortezomib mediated apoptosis. Taken together, our work reveals the important biological function of 14-3-3ζ in MM growth, survival and proliferation; the data also provides valuable information for the development of new therapeutic strategies facilitating drug sensitivity and overcoming drug resistance. Disclosures: Kaufman: Millenium: Consultancy; Onyx Pharmaceuticals: Consultancy; Novartis: Consultancy; Keryx: Consultancy; Merck: Research Funding; Celgene: Research Funding. Lonial:Onyx: Consultancy; Bristol-Myers Squibb: Consultancy; Novartis: Consultancy; Celgene: Consultancy; Millennium Pharmaceuticals, Inc.: Consultancy; Merck: Consultancy.

Simultaneous Inhibition of cIAP1, cIAP2 and XIAP Is Required for Inducing Apoptosis in Multiple Myeloma Cells.

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 2943-2943
Author(s):  
Vijay G. Ramakrishnan ◽  
Teresa K. Kimlinger ◽  
Utkarsh Painuly ◽  
Jessica Haug ◽  
S. Vincent Rajkumar ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Signaling Pathways ◽  
Cell Line ◽  
Cell Lines ◽  
Research Funding ◽  
Sensitive Cell ◽  
Sensitive Cell Line ◽  
Nfkb Pathway ◽  
Stat Pathway

Abstract Abstract 2943 Background: Inhibitor of apoptosis (IAP) proteins represents a conserved group of proteins that are important regulators of cell survival and apoptosis. X-linked IAP (XIAP) is the best studied IAP that inhibits pro-apoptotic caspases 3, 7 and 9. Multiple myeloma (MM) cell lines express high levels of XIAP. The levels of XIAP are further increased when stimulated by cytokines IL6 and IGF-1, both secreted in copious amounts in myeloma microenvironment. The other two main IAP proteins, namely cIAP1 and cIAP2 are not direct inhibitors of caspases. Instead, they modulate the levels of various signaling pathways by ubiquitinating proteins within the pathways. The NFKB pathway could be activated or inhibited by cIAP1 and 2. In MM, deletions of cIAP1 and cIAP2 have been shown to activate non-canonical NFKB pathway, which indicates a possible tumor suppressor role of these proteins. We wanted to investigate the role of the three IAPs by using a small molecule inhibitor. Our studies clearly indicate the importance of inhibiting all the three IAPs for the induction of apoptosis in MM cells. Methods: LCL161 was synthesized by Novartis Inc. (Basel, Switzerland). Stock solutions were made in DMSO, and subsequently diluted in RPMI-1640 medium for use. MM cell lines were cultured in RPMI 1640 containing 10% fetal bovine serum (20% serum for primary patient cells) supplemented with L-Glutamine, penicillin, and streptomycin. Cytotoxicity was measured using the MTT viability assay and proliferation using thymidine uptake. Apoptosis was measured using flow cytometry with Annexin V-FITC and propidium iodide (PI) for cell lines and patient cells. Immunoblotting was done on cell extracts at various time points following incubation with the drug in order to study the cell signaling pathways. siRNA to cIAP2 was purchased from Invitrogen and was electroporated into MM1S cells. Results: We first examined baseline levels of cIAP1, cIAP2 and XIAP in several MM cell lines and a few patient cells. We observed that the IAPs were constitutively expressed in MM cells. We then wanted to examine the functional significance of these IAP proteins in MM cells. For this, we used an IAP inhibitor LCL161. We observed that LCL161 was able to induce cytotoxicity and inhibit proliferation of MM cells, albeit with differences observed between cell lines. We then examined the factors contributing to resistance in the less sensitive cell lines. For this we chose H929, a sensitive cell line and MM1S, a less sensitive cell line to LCL161. Upon treatment with LCL161, cIAP1 and XIAP were down regulated accompanied by increase in levels of activated caspases 9, 8 and 3 in both H929 and MM1S cells. Using LCL161 in combination with a caspase 9 or a caspase 8 or a pan caspase inhibitor showed clearly that the extrinsic pathway is more involved in the LCL161 induced cell death process. LCL161, however, was unable to inhibit cIAP2 in the less sensitive cell line MM1S whereas cIAP2 was not found to be expressed in H929 cells. It has been shown that cIAP1 is required for ubiquitination and degradation of cIAP2. Therefore, cIAP1 down regulation by LCL161 could actually be contributing to the lack of down regulation of cIAP2 and the observed resistance to LCL161. In order to test this, we used a siRNA to cIAP2 and transfected it into MM1S cells by electroporation. We observed that the siRNA reduced cIAP2 levels and in combination with LCL161 led to marked increase in cells undergoing apoptosis. We also examined signaling pathways after treatment with LCL161 and observed upregulation of both canonical and non-canonical NFKB pathways and Jak/Stat pathway in MM1S cells and not in H929 cells. Combining LCL161 with a Jak2 specific inhibitor SD-1029 synergized in inducing cell death in MM1S and other cell lines less sensitive to LCL161. We are currently testing this combination in MM patient cells. Conclusion: These studies demonstrate the importance of inhibiting cIAP1, cIAP2 and XIAP together in MM cells. Furthermore, by this study we were able to identify resistance mechanisms that are upregulated due to inhibiting the IAP proteins and the importance of using agents that inhibit the IAPs along with inhibitors of these pathways in inducing apoptosis in MM cells. The findings from these studies form the basis of evaluation of IAP inhibitors in combination with a Jak/Stat pathway inhibitor in patients with MM. Disclosures: Kumar: Celgene: Consultancy, Research Funding; Merck: Consultancy, Honoraria; Millennium Pharmaceuticals, Inc.: Research Funding; Novartis: Research Funding; Genzyme: Research Funding; Cephalon: Research Funding.

VEGF Upregulates Mcl-1 Expression and Protects Multiple Myeloma Cells Against Starvation Induced-Apoptosis.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 631-631
Author(s):  
Steven Le Gouill ◽  
Klaus Podar ◽  
Martine Amiot ◽  
Teru Hideshima ◽  
Dharminder Chauhan ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Cell Proliferation ◽  
Cell Lines ◽  
Cell Cycle Progression ◽  
Myeloid Cell ◽  
Fibroblast Cell ◽  
Transfected Cells ◽  
Murine Embryonic Fibroblast ◽  
Induced Apoptosis

Abstract Vascular endothelial growth factor (VEGF) induces proliferation of MM cells and induces interleukin-6 (IL-6) secretion in a paracrine loop involving MM cells and bone marrow stromal cells. In turn, IL-6 triggers multiple myeloma (MM) cell proliferation and also protects against apoptosis by upregulating Myeloid-cell-leukemia 1 (Mcl-1), a critical survival protein in MM cells. The goal of our study was to investigate the role of Mcl-1 in VEGF induced-proliferation and protection against apoptosis. Using two murine embryonic fibroblast cell lines as a model (a Mcl-1 deleted cell line and its wild type: Mcl-1Δ/null and Mcl-1wt/wt MEFs, respectively), we here demonstrate that deletion of Mcl-1 reduces fetal bovine serum (FBS), VEGF, and IL-6 induced-proliferation. In addition, we demonstrate that the percentage of cells in S phase is lower in Mcl-1Δ/null compared to Mcl-1wt/wt MEFs (21% (+/−1) versus 30% (+/− 3), respectively). Taken together, these results demonstrate that Mcl-1 is required to mediate VEGF, Il-6 and FBS-induced-proliferation and cell cycle progression. To highlight the key anti-apoptotic role of Mcl-1 in MM cells, humans MM1s cells were transfected with Mcl-1 siRNA. Specific inhibition of Mcl-1 was associated with decreased proliferation (42% and 61% decreases at 24 and 48 h, respectively) and induction of apoptosis (subG1 peak: 22% and 41% in Mcl-1 siRNA transfected cells versus 15% and 15 % in non-transfected cells at 24 and 48 h, respectively), confirming that Mcl-1 is critical for both proliferation and protection against apoptosis in MM cells. In 3 human MM cell lines (MM1s, U266 and MM1R) and MM patient cells we next showed that Mcl-1 protein expression, but not other bcl-2 family members, is upregulated by VEGF in a time and dose manner; and conversely that the pan-VEGF inhibitor GW654652, blocks VEGF induced-upregulation of Mcl-1. Furthermore using flow cytometry with a double staining (CD38-FITC and Apo 2.7-PE), we demonstrate that VEGF protects MM patient cells from FBS-starvation-induced-apoptosis: the percentage of apoptotic MM patient cells (CD38++ and Apo 2.7+) in non starved medium (RPMI 1640 supplemented with 10% FBS) was 15% versus 93% in starved medium (RPMI 1640 supplemented with FBS 2%), and 48% in starved medium supplemented with 25ng/ml VEGF. In conclusion, our study demonstrates that VEGF protects MM cells against apoptosis, and that VEGF-induced MM cell proliferation and survival is mediated via Mcl-1. these studies provide the preclinical framework for novel therapeutics targeting both Mcl-1 and/or VEGF to improve patient outcome in MM.

Microrna Expression Profile Identifies Distinct Clinically Relevant Sub-Groups in Multiple Myeloma: Novel Prognostic Markers and Potential Targets for Therapy

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 96-96 ◽  
Author(s):  
Sophia Adamia ◽  
Herve AvetLoiseau ◽  
Samirkumar B Amin ◽  
Yu-Tzu Tai ◽  
Steven P. Treon ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Cell Differentiation ◽  
Clinical Outcome ◽  
Signaling Pathways ◽  
Cell Lines ◽  
Plasma Cells ◽  
Normal Plasma ◽  
Group A ◽  
Group B

Abstract MicroRNA, an abundant class of small endogenous RNAs, regulate target genes through inducing translational inhibition and cleavage of targeted transcripts. To date, microRNAs have been implicated in normal biological processes, including development, cell differentiation, apoptosis and proliferation as well as in malignant transformation. However, their role in multiple myeloma (MM) remains unknown. Here we investigated role of microRNAs in myelomagenesis, and their influence on prognosis and clinical outcome. We evaluated profiles of 384 microRNAs in bone marrow derived CD138+ plasma cells (PC) from 79 uniformly treated MM patients, 11 MM cell lines and 9 healthy donors using qRT-PCR based microRNA array. The relative expression was calculated using comparative Ct method, and data was normalized using endogenous controls and analyzed using SDS, RQ manager, R and dChip softwares. MicroRNA expression profiles detected in MM patients were correlated with clinical outcome measures. We observed significant modulate expression of 61 microRNAs in myeloma cells compared to normal plasma cells. When more stringent criteria were used, we identified 24 differentially expressed microRNAs in patient samples. Further, unsupervised hierarchical clustering of filtered microRNAs, based on their DCt values, identified two major groups within the MM population (groups A and group B). Samples of Group A clusters with MM cell lines, indicating more proliferative nature of MM patient cells. Within B group, a second degree node group B2, clusters with normal plasma cells indicating more indolent course, while patients in an additional node B1 represented an assorted pattern. The unsupervised clustering of all MM samples showed consistent changes in miR-30b, -30c, -30d, -142-5p, -24, -191, -181d, -374, -146b, -140, -145, -125a, -151, -223, -155, let7b, indicative of a role of these microRNA in myelomagenesis; while supervised analysis of samples within groups A and B identified modulated expression of different sets of miRNAs. In group A miR-585 and let-7f were upregulated 8–12 fold, while miRs -125a, -126, -155, -223, -146a, -374 -19a, -20a, -26a, -30a -5p, -30b, and -30d were significantly downregulated; in group B, all differentially expressed microRNAs were downregulated (p<0.001) compared to normal plasma cells. These modulated miRNAs target critical signaling pathways including apoptosis, hematopoietic cell differentiation and proliferation, survival and angiogenesis by upregulating function of HOX9, c-myc, VCAM-1, Bcl-2, E2F1, SHP1, SHP2, VEGF, and DUSp6 molecules. We further analyzed the effect of microRNA on clinical outcome. We have observed significantly superior event free and overall survival of patients in group B2 compared to patients in group A (2 yr estimated EFS 79% versus 54% respectively; p=0.05; and 2 yr estimated OS 94% versus 70% respectively; p =0.017). Taken together this data identifies critical microRNAs as modulators of gene expression and signaling pathways and provides potential novel microRNA and gene targets in MM to both understand biological behavior and for therapeutic application.

CYC065, a Potent Derivative of Seliciclib Is Active In Multiple Myeloma In Preclinical Studies

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 2999-2999 ◽  
Author(s):  
Samantha Pozzi ◽  
Diana Cirstea ◽  
Loredana Santo ◽  
Doris M Nabikejje ◽  
Kishan Patel ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Multiple Myeloma ◽  
Cell Line ◽  
Board Of Directors ◽  
Cell Lines ◽  
Preliminary Data ◽  
Research Funding ◽  
Preclinical Studies ◽  
Dependent Manner ◽  
Advisory Committees

Abstract Abstract 2999 Multiple myeloma (MM) is a treatable but incurable hematological malignancy and novel targeted therapies are under investigation. MM is characterized by dysregulation of the cell cycle, consequent to the overexpression of cyclins and their related kinases, the cyclins dependent kinases (CDK), a group of Ser/Thr proteine kinases. CDKs represent a promising therapeutic target, and inhibitors have been developed for anticancer treatment. We have previously studied seliciclib in the context of MM. CYC065, a second generation CDK inhibitor is the more potent derivative of seliciclib. It is mainly active on CDK 2, 5 and 9, involved in progression of the cell cycle and protein transcription. It has already shown promising results in preclinical studies in breast cancer and acute leukemia. We tested CYC065 in in vitro experiments in MM. Our preliminary data in 7 MM cell lines showed cytotoxicity of CYC065, both in MM cell lines sensitive as well as resistant to conventional chemotherapy, with an IC50 ranging between 0.06 and 2μ M, at 24 and 48h. Tritiated thymidine uptake assay confirmed the antiproliferative effects of CYC065 in MM, and its ability to overcome the growth advantage conferred by co-culture with bone marrow stromal cells derived from MM patients, and cytokines like interleukin 6 (10ng/ml) and insulin like growth factor-1 (50ng/ml). The anti-proliferative effect was evident both at 24 and 48h, starting at concentrations as low as 0.015μ M. The AnnexinV/PI assay in the MM1.s cell line confirmed CYC065's ability to induce apoptosis in a time dependent manner starting at 9 hours of treatment, at a concentration of 0.125 μ M, inducing 82% of apoptosis after 48h of exposure. Cell cycle analysis in the same MM1.s cell line showed an increase of subG1 phase, starting at 9 hours of treatment, at 0.125 μ M of CYC065. Preliminary results of western blot analysis confirmed the apoptotic effect of CYC065 in the MM1s cell line, highlighted by the cleavage of caspase 3, 8, 9 and PARP. The compound was tested in primary CD138+ cells isolated from three refractory MM patients, confirming its efficacy at 0.125 μ M, both at 24 and 48h. Comparative analysis in PBMCs from normal donors, for the evaluation of the drug toxicity is ongoing and will be presented. In conclusion our preliminary data confirm the efficacy of CYC065 in MM cell lines and primary MM cells, at nanomolar concentrations. Ongoing mechanistic and in vivo studies will delineate its role in the now increasing spectrum of CDK inhibitors in MM and better define its potential for clinical development in MM. Disclosures: Green: Cyclacel: Employment. Anderson:Millennium Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Scadden:Fate Therapeutics: Consultancy, Equity Ownership, Patents & Royalties. Raje:Celgene: Membership on an entity's Board of Directors or advisory committees; Astra Zeneca: Research Funding; Acetylon: Research Funding.

Pralatrexate Has Potent Activity Against Multiple Myeloma In Vitro and In Vivo, and Activity Correlates with Tumor RFC-1 and DHFR Expression

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 1831-1831 ◽  
Author(s):  
Michael Mangone ◽  
Luigi Scotto ◽  
Enrica Marchi ◽  
Owen A. O'Connor ◽  
Hearn J. Cho
Keyword(s):  
Multiple Myeloma ◽  
Cell Lines ◽  
Research Funding ◽  
Folate Metabolism ◽  
Nog Mice ◽  
Induced Apoptosis ◽  
Dose Dependent ◽  
Functional Biomarkers

Abstract Abstract 1831 Multiple myeloma (MM) is the second most common hematologic malignancy. Although there are effective new agents that can induce remission, relapse is inevitable and the disease is currently incurable. Progress in the treatment of this disease demands development of novel therapeutics and identification of functional biomarkers that may be used to distinguish tumors that are susceptible to specific targeted agents, creating a “personalized” therapeutic strategy for individual patients. We investigated these principles with anti-folates, which are not commonly used in MM but have demonstrated activity in this disease. Pralatrexate (PDX, 10-propargyl 10-deazaaminopterin) is a folate analogue that was rationally designed to have high affinity for Reduced Folate Carrier (RFC)-1, an oncofetal protein expressed in many cancers that actively transports folates into cells. PDX induced dose-dependent apoptotic cell death in a subset of human myeloma cell lines (HMCL) and CD138+ MM cells isolated from a clinical specimen. In sensitive cell lines, PDX exhibited 10-fold greater potency compared to the structurally related drug methotrexate (MTX). PDX induced dose-dependent, intrinsic apoptosis in sensitive HMCLs, characterized by cleavage of caspase-3 and -9 and accompanied by the loss of full-length Mcl-1, a Bcl-2 family protein that plays a critical role in drug-induced apoptosis in MM. Furthermore, the activity of PDX is not abrogated by the presence of exogenous interleukin-6 or by co-culture with HS-5 bone marrow stromal cells, both of which exert powerful survival effects on MM cells and can antagonize apoptosis in response to some cytotoxic chemotherapy drugs. Sensitivity to PDX-induced apoptosis correlated with higher relative levels of RFC-1 mRNA in sensitive compared to resistant HMCL. Resistant HMCL also exhibited a dose-dependent up-regulation of dihydrofolate reductase (DHFR) protein, a primary molecular target for anti-folates, in response to PDX exposure, whereas sensitive HMCL did not. These changes in functional folate metabolism biomarkers, high baseline RFC-1 expression and upregulation of DHFR in response to PDX, appeared to be mutually exclusive to sensitive or resistant HMCL, respectively. Importantly, PDX was also effective against sensitive HMCL in vivo in a novel mouse xenograft model. NOD/Shi-scid/IL-2Rγnull (NOG) mice were inoculated with MM.1s HMCL stably transduced to express both GFP and luciferase (GFP-luc). GFP-luc MM.1s cells engrafted into the long bones, pelvis, and vertebral column of NOG mice within 4–7 days after injection of cells, as assessed by in vivo bioluminescent imaging. Treatment with PDX resulted in a significant reduction in tumor burden after two doses. These results demonstrate that PDX has potent anti-myeloma activity in vitro and in vivo, and that RFC-1 expression and DHFR upregulation are robust functional biomarkers that may identify patients who are likely to benefit from PDX therapy. These data support further exploration of PDX therapy in clinical trials for MM and investigation of folate metabolism biomarkers as indices for treatment with this class of drugs. Improved anti-folates such as PDX are a promising class of agents that may be a valuable addition to the arsenal against MM. Disclosures: O'Connor: Celgene: Consultancy, Research Funding; Merck: Research Funding; Novartis: Research Funding; Spectrum: Research Funding.

Bcl-2 Antagonism Potentiates MEK1/2/Chk1 Inhibitor Lethality in Multiple Myeloma Cells Overexpressing Bcl-2 through a Stat3-Dependent Mechanism

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 4763-4763
Author(s):  
Xin-Yan Pei ◽  
Michael W Sanderson ◽  
Leena E Youssefian ◽  
Jessica Felthousen ◽  
Lora B Kramer ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Signaling Pathways ◽  
Cell Lines ◽  
Stromal Cells ◽  
Conflicts Of Interest ◽  
Down Regulation ◽  
Bh3 Mimetics ◽  
Survival Factor ◽  
Survival Signaling ◽  
Induced Apoptosis

Abstract Introduction: Multiple myeloma (MM) is characterized by deregulation of members of the Bcl-2 family of apoptotic regulatory proteins. This has led to the development of BH3-mimetics such as ABT-737 which inhibits Bcl-2/xL but not Mcl-1. Previously, we reported that simultaneous inhibition of Chk1 and MEK1/2 dramatically induced apoptosis in cultured and primary MM cells, including cells resistant to conventional agents, while sparing their normal counterparts (Pei et al., Blood 2007, 2011). Recently, we reported that this strategy circumvented MM cell resistance conferred by overexpression of Mcl-1, an important survival factor in this disease (Pei et al., PLoS One 2014). However, Bcl-2 overexpression confers significant resistance to the Chk1/MEK1/2 inhibition strategy. This raised the possibility that BH3-mimetics targeting Bcl-2 might circumvent this resistance mechanism. The purpose of the present studies was to determine whether BH3-mimetics could overcome such resistance while preserving anti-myeloma selectivity. An additional goal was to employ a new mathematical model to characterize interactions combining three novel agents that coordinately inhibit multiple survival signaling pathways. Methods: Various parental and Bcl-2 or Bcl-xL-over-expressing MM cell lines, as well as primary CD138+ MM cells were employed. ABT-737, the MEK1/2 inhibitor PD184352 (PD), and the Chk1/Wee1 inhibitor (Chk1i) were obtained from Abbott, Millipore and Calbiochem, respectively. Cells were exposed to agents alone or in various combinations for 4 -72 h, after which effects on apoptosis and signaling pathways were determined. Results: Co-administration of ABT-737 potentiated PD/Chk1i-mediated lethality in multiple parental MM cell lines, in association with Mcl-1 down-regulation, Bim up-regulation, and increased DNA damage (ΥH2A.X). Consistent with earlier findings, ectopic expression of Bcl-2 or Bcl-xL protected MM cells from the PD/Chk1i regimen. However, co-administration of ABT-737 significantly restored sensitivity towards PD/Chk1i lethality. Mathematical modeling indicated 3-agent synergistic interactions, particularly in Bcl-2 overexpressing cells. PD/Chk1i exposure inhibited phosphorylation (T705 and S727) of Stat3, another important survival factor for MM cells, while cells expressing constitutively active Stat3 (CA-STAT3) exhibited resistance to this regimen. However, the latter event was reversed by co-exposure to ABT-737. Moreover, combining ABT-737 with PD/Chk1i resulted in release of Bim from anti-apoptotic proteins including Bcl-2, Bcl-xL, and Mcl-1, accompanied by Bak and Bax conformational change (activation). Knock-down of Bim by shRNA significantly protected cells from apoptosis induced by the 3-agent combination, indicating a functional role for Bim in anti-MM activity of this regimen. Furthermore, similar interactions, together with down-regulation of pStat3, were also observed in bortezomib-resistant MM cells, as well as in patient-derived CD138+ MM cells. In contrast, the regimen was minimally toxic to normal cord blood CD34+ cells or CD138- bone marrow cells. Finally, co-culture of parental or bortezomib-resistant MM cells with HS-5 stromal cells induced up-regulation of pStat3, while treatment with ABT-737 in combination with PD/Chk1i prevented Stat3 activation and robustly induced apoptosis despite the presence of stromal cells. Conclusion: ABT-737 co-administration synergistically potentiates the lethality of the PD/Chk1i regimen in MM cells, including bortezomib-resistant and primary MM cells, but not in normal hematopoietic progenitors. It also overcomes PD/Chk1i resistance conferred by overexpression of Bcl-2 or Bcl-xL, as well as by microenvironmental factors. Mechanisms responsible for these interactions are likely to be multi-factorial, including inactivation of Stat3, up-regulation of Bim, release of Bim from Bcl-2, Bcl-xL, and Mcl-1, and activation of Bak and Bax. Collectively, these findings demonstrate that combining BH3-mimetics with Chk1/MEK1/2 inhibition circumvents multiple forms of drug resistance in MM cells while exhibiting minimal toxicit toward normal hematopoietic cells. They also argue that a strategy targeting three coordinate survival signaling pathways may be highly effective in killing MM cells, particularly those resistant to current anti-MM therapies. Disclosures No relevant conflicts of interest to declare.

scholarly journals Silica Nanoparticles Sensitize Human Multiple Myeloma Cells to Snake (Walterinnesia aegyptia) Venom-Induced Apoptosis and Growth Arrest

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Douaa Sayed ◽  
Mohamed K. Al-Sadoon ◽  
Gamal Badr
Keyword(s):  
Cell Cycle ◽  
Multiple Myeloma ◽  
Silica Nanoparticles ◽  
Biological Effects ◽  
Growth Arrest ◽  
Hematopoietic Stem ◽  
Human Multiple Myeloma ◽  
Induced Apoptosis ◽  
The Impact ◽  
Effective Treatments

Background. Multiple myeloma (MM), an almost incurable disease, is the second most common blood cancer. Initial chemotherapeutic treatment could be successful; however, resistance development urges the use of higher toxic doses accompanied by hematopoietic stem cell transplantation. The establishment of more effective treatments that can overcome or circumvent chemoresistance has become a priority. We recently demonstrated that venom extracted fromWalterinnesia aegyptia(WEV) either alone or in combination with silica nanoparticles (WEV+NPs) mediated the growth arrest and apoptosis of prostate cancer cells. In the present study, we evaluated the impact of WEV alone and WEV+NP on proliferation and apoptosis of MM cells.Methods. The impacts of WEV alone and WEV+NP were monitored in MM cells from 70 diagnosed patients. The influences of WEV and WEV+NP were assessed with flow cytometry analysis.Results. WEV alone and WEV+NP decreased the viability of MM cells. Using a CFSE proliferation assay, we found that WEV+NP strongly inhibited MM cell proliferation. Furthermore, analysis of the cell cycle using the propidium iodide (PI) staining method indicated that WEV+NP strongly altered the cell cycle of MM cells and enhanced the induction of apoptosis.Conclusions. Our data reveal the biological effects of WEV and WEV+NP on MM cells that enable these compounds to function as effective treatments for MM.

scholarly journals Revealing Transcriptome Deregulation upon Genomic Complexity in Multiple Myeloma

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 3-4
Author(s):  
Matteo Claudio Da Via' ◽  
Bachisio Ziccheddu ◽  
Matteo Dugo ◽  
Marta Lionetti ◽  
Katia Todoerti ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Cell Lines ◽  
In Silico ◽  
Copy Number ◽  
Drug Sensitivity ◽  
Genetic Alterations ◽  
Prognostic Impact ◽  
Immunoglobulin Gene ◽  
Driver Genes ◽  
The Impact

Introduction Multiple Myeloma (MM) is characterized by hyperdiploidy (HD) or immunoglobulin gene (IgH) rearrangements as initiating events. Clonal heterogeneity is a hallmark of its biology as highlighted by Next Generation Sequencing. In this context, data on the impact of peculiar mutations, copy number aberrations (CNAs), and chromosomal rearrangements (CRs) at the transcriptomic level are still scanty. In this study, we aimed to dissect the transcriptional deregulation promoted by the most recurrent genomic drivers. Based on this geno-trascriptomic link, we also aimed to identify biomarkers that could suggest personalized treatments. Methods We analyzed 517 newly diagnosed patients from the IA12 release of the CoMMpass study, focusing on mutations in MM driver genes, structural variants, copy number segments and raw transcript counts. RNAseq data was processed with the VOOM/LIMMA pipeline. To perform an in-silico drug sensitivity screen, we anchored cell lines to patients samples using the Celligner algorithm and interrogated the DepMap dataset. Results We first analyzed the global impact of genetic aberrations on the transcriptome. Chr(1q)amp/gain, followed by IgH translocations and HD showed the highest number of deregulated transcripts. Individual mutations had much less impact, with the exception of NRAS and chr(13q) genes (DIS3, TGDS, RB1). Next, we investigated differential influence between hotspots (HS) vs nonHS mutations within driver genes. KRAS and NRAS, showed little changes between nonHS and wild type (WT), as the transcriptome was mostly impacted by HS mutations. IRF4 K123 showed a specific transcriptional profile, while nonHS mutations still carried functional relevance although on different genes. For BRAF, the kinase dead D594 mutation surprisingly impacted the most in comparison to V600 and WT cases. Next, we explored the effect of bi-allelic genetic events with known prognostic impact. TP53 double-hits were associated with an upregulation of PHF19, a MM poor prognostic marker, and downregulation of SLAMF7, a new immunotherapy target. CYLD and TRAF3 double-hits correlated with NF-κB pathway activation, and the former showed a significant BCL2 upregulation. Bi-allelic events on chr13 exhibited gene-specific consequences: DIS3 inactivation deregulated mostly lncRNAs, while TGDS impacted on genes involved in cell-cycle regulation. Regarding chromosomal gains, only chr(1q)amp (&gt; 3 copies) showed a gene dosage effect with upregulation of the potential therapeutic targets MCL1 and SLAMF7. Given that the BCL2 axis was perturbated by several genetic alterations, we systematically compared the expression levels of BCL2, NOXA, MCL1 and BCL2L1 in CYLD inactivated, t(11;14) and chr(1q)amp patients. BCL2 levels were higher in the CYLD group, which parallels with the overexpression of the anti-apoptotic gene BCL2L1. NOXA, which promotes MCL1 degradation, was significantly upregulated in t(11;14). Chr(1q)amp patients showed a concomitant MCL1 overexpression and NOXA downregulation. To correlate these results to drug sensitivity, we performed an in-silico screen. We first selected MM and lymphoma cell lines from the DepMap dataset based on a gene expression profile that was most similar to the MM samples, then analyzed candidate drugs. The SKMM2 MM cell line, harboring t(11;14), del(CYLD) e NOXAamp was highly sensitive to Venetoclax. The same was true for the lymphoma ones RI1 and OCI-LY3, both harboring NOXAamp, but negative for t(11;14). On the contrary, the U266 and MOLP8 both with t(11;14) carrying a MCL1amp due to a chr(1q)amp were fully resistant. Of note, these latter resulted sensitive to the pan-BCL2 axis inhibitor Sabutoclax. Conclusions Our study suggests a link between the genomic architecture and transcriptome in MM, where CNAs and CRs had a stronger impact on expression than gene mutations. However, given that not all mutations are identical, HS ones need further testing as they may represent a future treatment target. Moreover, the mutational status is crucial since, while mono-allelic events are often of little transcriptional value, compound heterozygosity carries a huge influence on transcriptomic which provides biological basis for the observed prognostic impact of "double-hit" MM. Finally, we suggest that a comprehensive profiling of the BCL2 pathway may identify biomarkers of sensitivity to BCL2 inhibitors in addition to the t(11;14). Disclosures D'Agostino: GSK: Membership on an entity's Board of Directors or advisory committees. Corradini:Celgene: Consultancy, Honoraria, Other: Travel and accommodations paid by for; Sanofi: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Gilead: Consultancy, Honoraria, Other: Travel and accommodations paid by for; Incyte: Consultancy; Daiichi Sankyo: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Other; BMS: Other; F. Hoffman-La Roche Ltd: Consultancy, Honoraria; Amgen: Consultancy, Honoraria, Other: Travel and accommodations paid by for; Novartis: Consultancy, Honoraria, Other: Travel and accommodations paid by for; Servier: Consultancy, Honoraria; Kite: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria, Other: Travel and accommodations paid by for; KiowaKirin: Consultancy, Honoraria. Bolli:Celgene: Honoraria; Janssen: Honoraria.

scholarly journals DNA Methyltransferase Inhibitors Increase Expression of CD38 and Enhance Daratumumab Efficacy in Multiple Myeloma

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 5618-5618 ◽  
Author(s):  
Priya Choudhry ◽  
Margarette C. Mariano ◽  
Arun P Wiita
Keyword(s):  
Multiple Myeloma ◽  
Flow Cytometry ◽  
Cell Lines ◽  
Research Funding ◽  
Plasma Cells ◽  
Cpg Island ◽  
Ex Vivo ◽  
Single Agent ◽  
Cd38 Expression

Abstract Introduction: The anti-CD38 monoclonal antibody Daratumumab is highly effective against multiple myeloma, is well tolerated, and has high single agent activity as well as combination effects with lenalidomide-dexamethasone as well as bortezomib-dexamethasone. Patient response to daratumumab monotherapy is highly correlated with pretreatment levels of CD38 expression on MM plasma cells (Nijhof et al, Leukemia (2015) 29:2039) and CD38 loss is correlated with daratumumab resistance (Nijhof et al, Blood (2016) 128:959). As a result, there is significant interest in elucidating the regulation and role of CD38 in MM. Recently, All Trans Retinoic Acid (ATRA), a known small molecule inducer of CD38 in myeloid cells, as well as the FDA-approved histone deacetylase inhibitor panobinostat, were both demonstrated to induce CD38 in MM plasma cells leading to increased lysis by daratumumab. Examining ENCODE data, we found the presence of a CpG island at the first exon of CD38. We hypothesized that removing methylation sites from this CpG island may de-repress CD38 transcription and lead to increased CD38 protein at the cell surface in MM plasma cells. Therefore, here we studied the role of DNA methyl-transferase inhibitors (DNMTis), currently FDA-approved for treatment of myelodysplastic syndrome, as agents to potentiate daratumumab therapy. Methods: We treated MM cell lines (RPMI-8226, MM.1S, XG-1, KMS12-PE) with two different DNMTis, 5-Azacytidine and decitabine, and assessed CD38 cell surface expression by flow cytometry. Similarly, we treated MM patient bone marrow aspirates ex vivo and assessed induction of CD38 expression in the CD138 positive population by flow cytometry. We analyzed CD38 mRNA levels and total CD38 protein levels by qRT-PCR and western blotting respectively. ATRA was used as a positive control in all experiments. We further tested the functional effect of DNMTi treatment on MM cell lines using an Antibody Dependent Cell Cytotoxicity (ADCC) assay. Briefly, live treated cells were incubated overnight with daratumumab and NK92-CD16 transgenic cells at and E:T ratio of 20:1, and lysis was measured using CytoTox-Glo (Promega). Results: Flow analysis revealed that DNMTi treatment induces a 1.2-2 fold increase in CD38 surface protein expression in a dose-dependent manner across MM cell lines. DNMTi treatment consistently yielded similar or higher increases in CD38 expression than that seen in ATRA- or panobinostat-treated cells. Despite significantly lower single-agent cytotoxicity, we found that decitabine led to similar surface CD38 induction as 5-Azacytidine. By RT-qPCR, 5-Azacytidine increased CD38 mRNA expression ~3 fold versus DMSO control, compared to ~2 fold mRNA increase with ATRA. In functional ADCC assays, DNMTi treatment also led to greater lysis than ATRA. Furthermore, the combination of both DNMTi and ATRA was additive, leading to the greatest lysis by NK cells. In contrast, in ex vivo-treated patient samples, ATRA induced greater CD38 expression than 5-Azacytidine on malignant plasma cells. However, this result is expected since MM plasma cells from patients typically do not proliferate in standard ex vivo culture, and active DNA replication is a requirement for successful DNMT inhibition based on known mechanism of action. In patients, however, we anticipate that continual plasma cell proliferation will lead to effective increases in CD38 after DNMTi treatment, as found in MM cell lines here. Summary and Conclusions: Our results here demonstrate that CD38 expression in MM cells is regulated by DNA methylation and targeting DNMTs with small molecule inhibitors leads to increased vulnerability to Daratumumab treatment. We propose that combination treatment with DNMTi and Daratumumab can lead to higher efficacy of daratumumab in daratumumab-naïve MM, as well as reversal of daratumumab-resistance. These combinations should be tested in clinical trials. Disclosures Wiita: Sutro Biopharma: Research Funding; TeneoBio: Research Funding.

scholarly journals Tris DBA Palladium Overcomes Hypoxia Mediated Drug Resistance in Multiple Myeloma

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 2978-2978
Author(s):  
Pilar De La Puente ◽  
Barbara Muz ◽  
Feda Azab ◽  
Micah John Luderer ◽  
Jack L. Arbiser ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Multiple Myeloma ◽  
Flow Cytometry ◽  
Cell Proliferation ◽  
Drug Resistance ◽  
Cell Lines ◽  
Research Funding ◽  
Caspase 3 ◽  
Cellular Processes ◽  
Hypoxic Conditions

Abstract Introduction: Despite recent progress in novel and targeted therapies, multiple myeloma (MM) remains a therapeutically challenging incurable disease. The regulation of important cellular processes and its link to cancer presented Src as an attractive target for MM. Src is a non-receptor protein tyrosine kinase which regulates multiple fundamental cellular processes including cell growth, migration, survival and differentiation. Activated Src in cancer lead to studies with Src as a target for anti-cancer drugs, and numerous Src inhibitors have become available to test the importance of Src in tumor initiation and progression. In MM, it has been described that in cell lines and MM patient-derived tumors, c-Src is constitutively activated, which plays an important role in drug resistance mechanisms. Tris dibenzylideneacetone dipalladium (Tris DBA), a small-molecule palladium complex, was shown to reduce Src/NMT-1 complex in melanoma cells, as well as inhibit downstream signaling including mitogen-activated protein kinase (MAPK kinase) and phosphoinositol-3-kinase (PI3K). We suggest a novel strategy to improve the treatment of MM and overcome the drug resistance for the current therapeutic agents by specific inhibition of Src in MM cells by an organopalladium compound, Tris DBA. Methods: Tris DBA was prepared by Dr. Arbiser. MM cell lines (MM.1S, MM.1R, H929, RPMI-8826, and OPM2) and PBMCs were cultured with Tris DBA (0-10 µM) for 24h. MM cells were analyzed for cell proliferation by MTT assay; cell cycle by DNA staining with PI and analyzed by flow cytometry; apoptosis was analyzed by Annexin V/PI staining and analyzed by flow cytometry; and cell signaling associated with proliferation, cell cycle, and apoptosis was analyzed by western blotting. In addition, cell proliferation assay of Tris DBA with or without combination of proteasome inhibitors (PIs) bortezomib or carfilzomib for 24h was analyzed on the proliferation of MM cells in normoxic or hypoxic conditions. Moreover, we tested the effect of combination treatment on cell cycle and apoptosis signaling under normoxic conditions. We then evaluated the effect of Tris DBA on HIF1α expression, migration and drug resistance under normoxic or hypoxic conditions. Results: The Src inhibitor Tris DBA reduced the proliferation of MM cell lines with an IC50 of about 1.5 - 3 µM after 24h treatment as a single agent, while none of the normal PBMC controls showed effect on their proliferation in the same dose range. These results were consistent with the decreased expression of proliferation signaling proteins from MAPK pathways (pERK), as well as PI3K (pS6R). Src inhibition led to the induction of a sub-G1 peak, which indicated accumulating apoptotic cells shown by DNA staining with PI. Apoptosis was then analyzed by Annexin/PI and confirmed by cleavage of caspase-3 and PARP. We found that Tris DBA synergized with bortezomib and carfilzomib by inhibiting proliferation of MM cells and reducing cell cycle protein signaling more than either of the drugs alone. Moreover, the Tris DBA/Bortezomib or Tris DBA/Carfilzomib combination therapies significantly increased apoptosis by caspase-3 cleavage more than treatment with either proteasome inhibitor individually. Tris DBA inhibited HIF1α expression in both normoxic and hypoxic conditions. HIF1α is an important target for hypoxia-driven drug resistance. Our studies confirmed hypoxia promoted faster chemotaxis of MM cells towards the chemo-attractants found in stromal cell conditioned media, and that Tris DBA treatment could overcome this hypoxia-induced effect. In addition, the development of hypoxia-induced drug resistance to individual bortezomib or carfilzomib treatment was overcome with combination treatment of Tris DBA under hypoxic conditions. Conclusions: Tris DBA reduces proliferation and induces G1 arrest and apoptosis in MM cells. Tris DBA synergized with PIs reducing proliferation and cell cycle signaling, as well as increasing apoptosis more than each drug alone. Tris DBA overcame hypoxia-induced effects such as enhanced chemotaxis or drug resistance to PIs by inhibition of HIF1α expression. Moreover, we found that Tris DBA is an effective anti-myeloma agent alone or in combination with other targeted drugs and that it reverses hypoxia-induced drug resistance in myeloma. These results suggest the use of Tris DBA as a new therapeutic agent in relapsed refractory myeloma. Disclosures Arbiser: ABBY Therapeutics: Other: Jack L Arbiser is listed as inventor on a US Patent for imipramine blue. He is cofounder of ABBY Therapeutics, which has licensed imipramine blue from Emory University.. Azab:Verastem: Research Funding; Targeted Therapeutics LLC: Other: Founder and owner ; Selexys: Research Funding; Karyopharm: Research Funding; Cell Works: Research Funding.

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