scholarly journals Dissecting the Mechanisms of Activity of SLAMF7 and the Targeting Antibody Elotuzumab in Multiple Myeloma

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 3431-3431 ◽  
Author(s):  
Siobhan Glavey ◽  
Michaela Reagan ◽  
Salomon Manier ◽  
Michele Moschetta ◽  
Yawara Kawano ◽  
...  
Keyword(s):  
Research Funding ◽  
Xenograft Model ◽  
Myeloma Cell ◽  
Tumor Burden ◽  
Advisory Board ◽  
Xenograft Models ◽  
Human Igg1

Abstract Background Signaling lymphocytic activation molecule family 7 (SLAMF7) is a cell surface receptor which is expressed at high levels in multiple myeloma (MM) cells and serves as a therapeutic target in this disease. Elotuzumab, a humanized monoclonal antibody targeting SLAMF7, has shown promising activity, particularly in combination with lenalidomide, in MM patients in the clinical trial setting. While the primary mechanism of action of elotuzumab in pre-clinical in vitro studies has been shown to be antibody-dependent cellular cytotoxicity (ADCC) mediated via NK-cell CD16, other possible mechanisms of activity of elotuzumab in MM are not well defined. Specifically, the downstream signaling effects of SLAMF7 have not been delineated in myeloma cells. We set out to examine the effect of stable SLAMF7 knockdown (KD) on MM tumor development in vivo and evaluated the ability of elotuzumab to exert an anti-myeloma effect within the bone marrow niche in MM mouse models. Methods: In-vitro: KD of SLAMF7 was performed in myeloma cell line MM1s using lentiviral shRNAs targeting different regions in the SLAMF7 mRNA. Specific SLAMF7 knockdown was confirmed by reduced SLAMF7 mRNA and protein expression in comparison to cells receiving scrambled control shRNA lentivirus. Survival of SLAMF7 KD cells in comparison to scrambled control cells was assessed by MTT assay. The effect of elotuzumab treatment on the survival of MM1s cells was also assessed. In vivo: Tumor Xenograft models SLAMF7 KD; MM1S-GFP-Luc+ cells (5X106) were injected intravenously (IV) into SCID-Bg mice (n=7/group) and animals underwent bioluminescent imaging (BLI) weekly following injection. Xenograft models elotuzumab; Forty eight hours after IV injection of MM1S-GFP-Luc+ cells (5X106) elotuzumab or human IgG control antibody (both 10mg/kg) was administered via intraperitoneal (IP) injection twice weekly and mice (n=7/group) were followed for tumor burden and survival outcomes. A follow up study was performed (n=5/group) using a modified form of elotuzumab (IgG1.1mAb 10mg/kg IP) harboring mutations in the IgG1 CH2 domain which decreases ADCC via decreased Fc-γ receptor binding allowing evaluation of the CD16 mediated effect in this model. Results SLAMF7 KD resulted in a significant reduction in the survival of MM1s cells at 24 hours as assessed by MTT assay (P = 0.001). No significant reduction in survival was noted for the MM1s myeloma cell line following elotuzumab treatment at 24 hours in the absence of effector cells. Interestingly, knockdown of SLAMF7 resulted in a reduction in tumor burden in the SCID-Bg xenograft model as assessed by weekly BLI signal (P = 0.005 at week 6) with a consequent increase in survival for mice receiving SLAMF7 KD cells. (average 49 vs. 110 days Log Rank P<0.0001). Treatment of mice that had been administered MM1s cells and subsequently treated with elotuzumab resulted in a significant reduction in tumor burden (P = 0.001 at 5 weeks) and prolonged survival (Log Rank P = 0.0001) compared to human IgG1 control antibody treated mice (n=7/group). A follow up 3 arm study comparing IgG1.1f mAb to elotuzumab or human IgG1 control antibody (n=5/group) demonstrated no significant difference in tumor burden between the group receiving IgG1.1 mAb (no CD16 binding) and human IgG1 control antibody (P =0.8 at week 3). The difference in tumor burden between IgG1.1 mAb and elotuzumab was significant (P = 0.019 at 3 weeks) indicating that the effect on tumor burden seen in these mice was indeed CD16 dependent. Conclusions Knockdown of SLAMF7 in MM cells results in reduced tumor burden and survival in xenograft mice, indicating that SLAMF7 potentially plays a role in tumor biology in this disease. In addition elotuzumab treatment reduces tumor burden in a xenograft model of MM with defective NK cells in a CD16 dependent manner indicating that additional mechanisms beyond ADCC may be important in mediating the anti-myeloma effect of elotuzumab. Disclosures Glavey: BMS: Consultancy, Research Funding. Robbins:Bristol-Myers Squibb: Employment; Bristol-Myers Squibb: Equity Ownership. Ghobrial:Onyx: Advisory board Other; BMS: Advisory board, Advisory board Other, Research Funding; Noxxon: Research Funding; Sanofi: Research Funding.

MLN9708 Elicits Pharmacodynamic Response in the Bone Marrow Compartment and Has Strong Antitumor Activity in a Preclinical Intraosseous Model of Plasma Cell Malignancy.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 1834-1834 ◽  
Author(s):  
Edmund Lee ◽  
Bret Bannerman ◽  
Michael Fitzgerald ◽  
Jennifer Terkelsen ◽  
Daniel Bradley ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Antitumor Activity ◽  
Plasma Cell ◽  
Research Funding ◽  
Ex Vivo ◽  
Xenograft Model ◽  
Tumor Burden ◽  
Human Multiple Myeloma ◽  
Cell Malignancy

Abstract Abstract 1834 Poster Board I-860 Introduction The clinical success of VELCADE® (bortezomib) for Injection has validated the proteasome as a therapeutic target for the treatment of human cancer. The novel proteasome inhibitor MLN9708 is a potent, reversible, and specific inhibitor of the b5 site of the 20S proteasome identified in preclinical studies. MLN9708 is currently in human clinical development for both hematological and non-hematological malignancies. Here we describe the pharmacodynamic (PD) response of MLN9708 in the murine bone marrow compartment and its strong antitumor activity in an intraosseous xenograft model of plasma cell malignancy. Materials MLN9708 immediately hydrolyzes to MLN2238, the biologically active form, upon exposure to aqueous solutions or plasma. MLN2238 was used for all preclinical studies described below. Methods It has been previously shown that double transgenic iMycCa/Bcl-XL mice develop de novo plasma cell malignancies (J. Clin. Invest. 113:1763-1773, 2004) in which neoplastic plasma cell development is driven by the targeted expression of the transgene Myc (c-myc; myelocytomatosis oncogene) and Bcl-x (Bcl2l1; encodes the oncoprotein Bcl-XL). DP54 is a plasma cell tumor cell line derived from the bone marrow of a syngeneic mouse previously inoculated with an iMycCa/Bcl-XL tumor (Cancer Res. 67:4069-4078, 2007). In vitro, DP54 cells express both the Myc and Bcl-XL transgenes, various plasma cell and B-cell markers including CD38, CD138 and B220, and has gene expression profile very similar to human multiple myeloma. To establish a preclinical intraosseous model of plasma cell malignancy for efficacy studies, freshly dissociated DP54-Luc cells (constitutively expressing firefly luciferase under a mouse Ig-k promoter) were aseptically injected into the bone marrow space of the upper shaft of the right tibia of NOD-SCID mice. Once tumor growth has been established, mice were randomized into treatment groups and then treated intravenously (IV) with vehicle, bortezomib (at 0.8 mg/kg twice weekly [BIW]) or MLN2238 (at 11 mg/kg BIW) for 3 consecutive weeks. Tumor burden was measured by bioluminescent imaging. Results MLN2238 strongly inhibited proteasome activity in the blood and bone marrow compartments of mice (maximum b5 inhibition of 84% and 83%, respectively). In vivo, when DP54 cells were aseptically injected into the bone marrow space of the mouse tibia, signs of bone erosion in the tibia, femur and cranial sagittal sultures (as determined by ex-vivo mCT imaging) were observed which resembled osteolytic lesions frequently seen in human multiple myeloma. Dissemination of DP54-Luc cells after intratibia inoculations were detected by in vivo bioluminescent and confirmed by ex vivo imaging where luminescent tumor nodules were detected in the spleen, kidneys, intestine, lymph nodes and bones including right tibia, spine and cranium. To assess the antitumor activity of MLN2238 in the bone marrow compartment, an efficacy study was performed using the DP54-Luc intraosseous xenograft model of plasma cell malignancy. Tumor burden (bioluminescence), osteolytic lesions (mCT) and overall survival after treatment with bortezomib and MLN2238 will be presented. Conclusion The novel proteasome inhibitor MLN9708 demonstrates strong activity in the bone marrow compartment in vivo. MLN9708 is currently in human clinical development for both hematological and solid tumor indications. Disclosures Lee: Milllennium: Employment, Equity Ownership. Bannerman:Milllennium: Employment. Terkelsen:Milllennium: Employment. Bradley:Milllennium: Employment, Equity Ownership, Research Funding. Li:Milllennium: Employment. Li:Milllennium: Employment. Janz:Milllennium: Research Funding. Van Ness:Milllennium: Research Funding. Manfredi:Milllennium: Employment. Kupperman:Milllennium: Employment.

Silencing The Sialyltransferase Gene ST3GAL6 Inhibits Adhesion and Migration Of Myeloma Cells In Vitro and Reduces The Homing and Proliferation Of Tumor Cells In Vivo

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 275-275
Author(s):  
Siobhan Glavey ◽  
Salomon Manier ◽  
Antonio Sacco ◽  
Michaela R Reagan ◽  
Yuji Mishima ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Cell Lines ◽  
Research Funding ◽  
Advisory Board ◽  
Myeloma Cells ◽  
Sialyl Lewis ◽  
And Migration ◽  
Rpmi 8226

Abstract Background Glycosylation is a stepwise procedure of covalent attachment of oligosaccharide chains to proteins or lipids, and alterations in this process, especially increased sialylation, have been associated with malignant transformation and metastasis. The adhesion and trafficking of multiple myeloma (MM) cells is strongly influenced by glycosylation and multiple myeloma cells express a variety of adhesion molecules, including selectin ligands and integrins, which are typically dependent on glycosylation for their function. We have previously reported that the sialyltransferase ST3GAL6 is up-regulated in plasma cells from MM patients and that increased expression is associated with inferior overall survival (OS) in MM gene expression profiling (GEP) datasets. The functional significance of increased sialylation of MM cells has not previously been reported. Methods MM cell lines MM1s and RPMI-8226 were confirmed to have high expression levels of ST3GAL6 at the gene and protein level compared to healthy controls. Knockdown of ST3GAL6 was confirmed in MM cell lines RPMI-8226 and MM1s using lentiviral shRNAs targeting different regions in the ST3GAL6 mRNA. Specific ST3GAL6 knockdown was confirmed by reduced ST3GAL6 mRNA and protein expression in comparison to a scrambled control. In a calcein-AM fluorescence based adhesion assay we next evaluated the effects of ST3GAL6 knockdown on MM-cell adhesion to bone marrow stromal cells (BMSC’s) and fibronectin coated plates. Migration to 30nM SDF1-α was assessed using transwell plates comparing ST3GAL6 knockdown cells to scrambled controls. The commercially available sialyltransferase inhibitor 3Fax-Neu5Ac was used to pre-treat MM cells in vitro prior to assessment of apoptosis by flow cytometry. shST3GAL6 MM1s cells positive for green fluorescent protein and luciferin (GFP-Luc+) were injected into tail veins of SCID-Bg mice (5x106 cells, n=5/group) and mice were followed weekly using bioluminescent imaging (BLI) for tumor development. Bone marrow homing of tumor cells was assessed using in vivoconfocal imaging of the skull vasculature (n=3/group). Results Knockdown of ST3GAL6 in MM cell lines resulted in a 50% reduction in cell surface staining with the monoclonal antibody HECA-452. This indicated reduced expression of cutaneous lymphocyte associated antigen (CLA), a carbohydrate domain shared by sialyl Lewis X (sLex) and sialyl Lewis a (sLea) antigens, confirming suppression of ST3GAL6 activity. There was a significant reduction in the ability of knockdown cells to adhere to BMSC’s and fibronectin in-vitro compared to scrambled controls (P=0.016, 0.032 respectively). Migration ability of these cells in response to SDF1-α was also reduced (P=0.01). In vivo in a xenograft SCID-Bg mouse model shST3GAL6 cells demonstrated a reduced tumor burden as assessed by weekly BLI (P=0.017 at week 4). A consolidated map of the skull bone marrow niche in mice injected with shST3GAL6 MM1s GFP-Luc+ cells revealed a reduced homing ability of these cells in comparison to mice injected with scrambled control cells. Treatment of the MM cell lines MM1s and RPMI-8226 with a sialyltransferase inhibitor 3Fax-Neu5Ac resulted in almost complete elimination of cell surface sLex and/or sLea expression as determined by HECA-452 staining. Following pre-treatment with 3Fax-Neu5Ac, MM1S cells grown in co-culture with BMSC’s cells showed increased sensitivity to Bortezomib compared to cells treated with bortezomib alone. Conclusions shRNA knockdown of ST3GAL6 in MM cells significantly inhibits adhesion and migration in vitro with reduced homing and proliferation potential in vivo. In conjunction with the results of enzymatic inhibition this indicates that sialylation may play an important role in the malignant behavior of MM cells. Studies are ongoing to address the potential role of altered glycosylation in MM. Disclosures: Ghobrial: Onyx: Advisoryboard Other; BMS: Advisory board, Advisory board Other, Research Funding; Noxxon: Research Funding; Sanofi: Research Funding.

Constitutive and Immunoproteasome Inhibitors Increase IκB and Decrease NF-κB Expression In Dendritic Cell

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 3493-3493
Author(s):  
Ahmad-Samer Samer Al-Homsi ◽  
Zhongbin Lai ◽  
Tara Sabrina Roy ◽  
Niholas Kouttab
Keyword(s):  
Multiple Myeloma ◽  
T Cell ◽  
Cell Lines ◽  
Mechanism Of Action ◽  
Peripheral Blood ◽  
Research Funding ◽  
Myeloma Cell ◽  
Multiple Myeloma Cell

Abstract Introduction Constitutive and immunoproteasome inhibitors (C&IPI) were thought to suppress nuclear factor-κB (NF-κB) pathway by preventing IκB degradation, which prevents NF-κB translocation into the nucleus. This mechanism of action has since been questioned by a number of studies. First, bortezomib promoted constitutive NF-κB activity in endothelial cell carcinoma. Second, NF-κB constitutive activity was resistant to bortezomib in multiple myeloma cell lines. Third, bortezomib increased IκB mRNA but post-transcriptionally downregulated IκB in normal cells and in multiple myeloma cell lines resulting in induced canonical NF-κB activation. Lastly, bortezomib increased nuclear levels of IκB as opposed to lowering cytoplasmic levels in cutaneous T cell lymphoma cell line suggesting that nuclear translocation of IκB was possibly responsible for NF-κB inhibition. The inhibitory activity of C&IPI on dendritic cells (DC) is of interest in the prevention of graft versus host disease (GvHD). It has been shown that different C&IPI impede DC maturation and T cell priming both in vitro and in vivo. Herein we sought to understand the mechanism of action of proteasome and immunoproteasome inhibitors on DC and to test their effect on IκB and NF-IκB expression. Materials and Methods We first performed RT PCR on lysates of DC obtained from the peripheral blood of 7 patients who received post-transplant cyclophosphamide and bortezomib as prevention of GvHD on a phase I clinical trial. Patients received allogeneic transplantation from matched-related or unrelated donors. Patients received no other immunosuppressive therapy except for rabbit anti-thymocyte globulin for those receiving graft from unrelated donor. Steroids were not allowed on the study. Samples were obtained on days +1, +4, and +7. The results were analyzed in comparison to samples obtained on day 0 before stem cell infusion. We then performed the same experiment on lysates of DC obtained from the peripheral blood of healthy volunteer donors. DC were untreated or incubated with bortezomib (10 nM for 4 h), carfilzomib (30 nM for 1 h), oprozomib (100 nM and 300 nM for 4 h), ONX 0914 (200 nM for 1 h), PR-825 (125 nM for 1 h), or PR-924 (1000 nM for 1 h). The drug concentration and duration of exposure were chosen based on the IC50 on proteasome activity and to reproduce in vivo conditions. We also performed IκB western blot on DC isolated from peripheral blood of healthy volunteers, untreated or incubated with bortezomib (10 nM for 4 h) or oprozomib (300 nM for 4 h). Each experiment was performed at least in triplicate. Results We found that the combination of cyclophosphamide and bortezomib significantly and progressively increased IκB mRNA while decreasing NF-κB mRNA in DC studied ex vivo. We also found that all studied C&IPI increased IκB mRNA to a variable degree while only oprozomib (300 nM) decreased NF-κB mRNA in DC in vitro. Finally, both bortezomib and oprozomib increased IκB protein level in DC in vitro (figure). Conclusion Our data suggest that C&IPI increase IκB expression in DC. As opposed to the previously reported data in other cell types, the effect is not associated with post-transcriptional downregulation. Cyclophosphamide and bortezomib also decrease NF-κB expression in DC in vivo while only oprozomib had the same effect in vitro. The effect of C&IPI on IκB and NF-κB expression may represent a new mechanism of action and suggests their effect may be cell-type dependent. Disclosures: Al-Homsi: Millennium Pharmaceuticals: Research Funding. Off Label Use: The use of cyclophosphamide and bortezomib for GvHD prevention. Lai:Millennium Pharmaceuticals: Research Funding.

siRNA for the Ig Light Chain Constant Region Reduces Light Chain Production and Secretion By Human Plasma Cells and in a Murine Xenograft Model

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 5722-5722
Author(s):  
Xun Ma ◽  
Ping Zhou ◽  
Monika Pilichowska ◽  
Chakra P Chaulagain ◽  
Sandy Wong ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Human Plasma ◽  
Cell Lines ◽  
Light Chain ◽  
Plasma Cells ◽  
Xenograft Model ◽  
Myeloma Cell ◽  
Constant Region

Abstract Background Ig light chain (LC) diseases such as AL amyloidosis and monoclonal light-chain deposition disease are caused by pathologic free LC. Treatment is aimed at eliminating LC production but success is limited. RNA interference (RNAi) can stop LC production but the diversity of LC variable region sequences poses a challenge that targeting consensus sequences in the constant region (CR) of LC mRNA may overcome (Blood 2014;123:3440). We have developed siRNA pools designed to target the κ or λ LC CR mRNA in human plasma cells and impair LC production and secretion, and have shown that the pool targeting the λ LC CR can do so, and can also trigger a terminal unfolded protein response in clones producing intact Ig due to intracellular accumulation of unpaired heavy chains (ibid). Here we report the results of continued in vitro and in vivo testing of these pools in patient specimens and in a murine xenograft model. Methods Pools of siRNA for the κ or λ LC CR (si[IGLCκCR], si[IGLCλCR]) were custom produced with a non-target control (si[-]). They were introduced in vitro into human plasma cells by an optimized streptolysin O-based method (SLO) and in a NOD.SCID xenograft flank plasmacytoma model by in vivo electroporation as per Gene Therapy 2011;18:1150. In vitro we evaluated LC gene expression, production and secretion at 24 hours in human myeloma cell lines and CD138-selected specimens from patients with plasma cell neoplasms, using real-time PCR (qPCR) for LC mRNA, flow cytometry for intracellular LC mean fluorescence intensity (MFI) and ELISA (Bethyl Laboratories) for LC secretion in 24-hour suspension cultures (106 cells/ml). In vivo we inoculated each of the flanks of NOD.SCID mice with 107 human myeloma cells (ALMC-1 or ALMC-2). When plasmacytomas were 0.5cm3 we injected si[IGLCλCR] or si[-] one time to each flank plasmacytoma respectively, allowing each mouse to serve as its own control. Two days later, the mice were sacrificed and the plasmacytomas excised for qPCR for λ LC mRNA and serum was obtained to measure human λ LC levels by ELISA. Results We have previously described results with siRNA targeting the λ LC CR in human cell lines that make λ LC (ALMC-1, ALMC-2, EJM, OPM2, MM.1S, and MM.1R) and in 16 AL λ patient specimens. We demonstrated significant decreases in LC mRNA, intracellular LC MFI, and λ LC secretion by cell lines (Blood 2014;123:3220); moreover, transcriptional profiling indicated minimal off-target effects (ibid; Supplement). We now report that in vitro secretion of λ LC by CD138-selected plasma cells from AL patients (n=3, newly diagnosed λ) treated with si[IGLCλCR] was reduced by 65% from a mean of 3.1 to 1.0µg/ml and that the residual λ LC mRNA was 49% of control. Similarly we treated κ LC secreting human myeloma cell lines with si[IGLCκCR] and si[-] (IM9, H929, JJN-3, and ARH77). By qPCR the residual κ LC mRNA was 13%, by flow cytometry the MFI was reduced by a median of 67.3% (22.5-90.8), and by ELISA mean κ LC secretion was reduced from 3.7 to 0.8µg/ml (P = 0.055, paired t test). We treated CD138-selected κ patient samples (AL 3, LCDD 1, MM 6) in the same way. By qPCR the residual κ LC mRNA was 57% control, by flow cytometry the MFI was reduced by a median of 37.5% (14-69.8), and by ELISA secretion was reduced from 9.4 to 6.5µg/ml (P = 0.02, paired t test). In the murine dual-flank xenograft model employing λ secreting cells, by qPCR there was a reduction in λ LC mRNA with si[IGLCλCR] treatment in 13 of 16 mice (ALMC-1 11/114, ALMC-2 2/2). In these 14, the median λ LC expression was 66% of control (range, 17-97). In 6/13 the average reduction in λ LC expression was 59%. Of note, measurable levels of human λ LC were found in the blood of all mice at sacrifice. Conclusion With one pool of siRNA targeting the constant region of the κ or λ LC we can significantly reduce production and secretion of LC by clonal human plasma cells, including patient cells, and also reduce the expression of LC in xenograft plasmacytomas in vivo. Two methods of siRNA delivery have been employed in this work thus far, SLO and in vivo electroporation, neither of which require endosomal escape. The specificity of the siRNA pools for plasma cell LC genes and the possible receptivity of plasma cells to RNAi are important positive aspects of this work. Further pre-clinical development of Ig LC CR RNAi employing lipid-based nanoparticle platforms is warranted in order to optimize cell-specific delivery, delivery efficiency and siRNA targeting. Disclosures No relevant conflicts of interest to declare.

Ascorbic Acid Overcomes Drug Resistance in Myeloma and Significantly Increases the Anti-Myeloma Effects of both Arsenic Trioxide and Melphalan in Vitro and in Vivo.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2470-2470 ◽  
Author(s):  
Richard A. Campbell ◽  
Haiming Chen ◽  
Daocheng Zhu ◽  
Janice C. Santos ◽  
Benjamin Bonavida ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Arsenic Trioxide ◽  
Cell Lines ◽  
Synergistic Effects ◽  
Myeloma Cell ◽  
Tumor Burden ◽  
Early Results ◽  
Mtt Assays

Abstract Glutathione levels have previously been shown to be associated with the development of resistance to a variety of anti-myeloma therapies. Ascorbic acid (AA) depletes intracellular glutathione levels which, in turn, should increase the sensitivity of tumor cells to anti-myeloma agents such as arsenic trioxide (ATO) and melphalan. To determine the synergistic effects of combining AA, with ATO and/or melphalan, we evaluated the effects of these combinations with MTT assays on myeloma cell lines in vitro and using our severe combined immunodeficient (SCID)-hu murine myeloma models. We determined the synergistic effects of combining AA with ATO and/or melphalan on the myeloma cell lines RPMI8226, 8226/dox, U266, and U266/dox in vitro. MTT assays demonstrated marked synergistic anti-proliferative effects of AA at 10 mM when added to these cell lines in the presence of ATO concentrations ranging from 5x10−5 M – 5x10−9 M, and melphalan concentrations ranging from 3x10−5 M – 3x10−9 M. In order to provide further evidence for the clinical relevance of these synergistic effects of AA, we investigated the potential of AA to increase the efficacy of current anti-myeloma therapies in our SCID-hu murine model of human myeloma LAGλ–1 (Yang H et al. Blood 2002). Each SCID mouse was implanted with a 0.5 cm3 LAGλ–1 tumor fragment into the left hind limb muscle. Twenty-eight days following implantation, mice then received treatment intraperitoneally (IP) with either AA (300 mg/kg) daily x5/week, ATO (1.25 mg/kg) daily x5/week, or melphalan (3.0 mg/kg) x1/week, or the combination of these agents. AA, ATO, and melphalan alone have no anti-myeloma effects at these doses, whereas AA+melphalan results in significantly decreased tumor burden and paraprotein levels. The most profound anti-myeloma effects were observed in animals treated with all three drugs together. These data show not only the additional synergistic anti-myeloma effects of AA on both ATO and melphalan in vitro but for the first time suggest that these effects are also present in vivo. This provides the rationale for combining AA with these agents in myeloma patients with resistant disease. In support of this, early results of clinical trials using the combination of AA, ATO and low doses of oral melphalan are promising.

Chimeric Antigen Receptor Modified T Cells Directed Against CD19 (CTL019 cells) Have Long-Term Persistence and Induce Durable Responses In Relapsed, Refractory CLL

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 4162-4162 ◽  
Author(s):  
David L. Porter ◽  
Michael Kalos ◽  
Noelle V. Frey ◽  
Stephan A. Grupp ◽  
Alison W. Loren ◽  
...  
Keyword(s):  
Gene Therapy ◽  
T Cells ◽  
Research Funding ◽  
P53 Mutation ◽  
Advisory Board ◽  
Scientific Advisory ◽  
Cell And Gene Therapy ◽  
Signaling Domains

Abstract Background Chimeric antigen receptors (CARs) combine the antigen recognition domain of an antibody with intracellular signaling domains into a single chimeric protein. CD19 is an ideal target for CARs since expression is restricted to normal and malignant B cells. Inclusion of the CD137 (4-1BB) signaling domain results in potent antitumor activity and in-vivo persistence of anti-CD19 CAR-modified T cells in mice. Lentiviral transduction into T cells facilitates strong surface expression of the CAR. We reported anti-tumor activity of CAR-modified autologous T cells targeted to CD19 (CTL019 cells) in 3 patients (pts) with CLL with relatively short follow up (Porter, et al NEJM 2011; Kalos et al Sci Trans Med 2011). We now report on outcomes and longer follow up from our pilot study treating 14 pts with relapsed, refractory CLL. Methods Autologous T cells collected by leukapheresis were transduced with a lentivirus encoding anti-CD19 scFv linked to 4-1BB and CD3-ζ signaling domains. Gene-modified T cells were expanded and activated ex-vivo by exposure to anti-CD3/CD28 beads. Pts had to have relapsed or persistent disease after at least 2 previous treatments (1 prior therapy for patients with p53 mutation) and progressed at least within 2 years of their last therapy. All pts received lymphodepleting chemotherapy ending 3-5 days before T cell infusion. The target dose of cells was 5 x 109 mononuclear cells with an expected transfection efficiency of 10-40% (total CTL019 dose 5x108 – 2 x 109 total cells). Cell infusions were planned over 3 days (10% on day 1, 30% of day 2, and 60% on day 3) but were held for fevers or other toxicity. Results 14 patients were treated on this pilot study including 12 men and 2 women with a median age of 67 (51-78). Pts had received a median of 4 prior therapies (1-10) and 6 pts had a mutation of p53. All pts had active disease at the time of CTL019 cell infusion. Lymphodepleting chemotherapy was Fludarabine/cyclophosphamide (3), pentostatin/cyclophosphamide (5), or bendamustine (6). A median of 7.5 x 108 total cells (range 1.7-50), corresponding to 1.4 x 108(range 0.14-5.9) genetically modified cells were infused over day 0, 1 and 2. There were no infusional toxicities >grade 2 though 6 pts developed fevers within 24 hrs of infusion #1 (3) or #2 (3) and did not receive additional CTL019 cells. Median follow-up as of July 15, 2013 was 9.4 mo (4-35) for all pts and 16 mo (5-35) for the 8 responding pts. 3 patients (21%) achieved a CR (follow-up 11, 34, and 35 mo), 5 (36%) achieved a PR (med follow up 11 mo, range 5-27 mo) and 6 (43%) had no response, for an overall major response rate of 57%. 2 of 5 pts with a PR progressed 4 mo after infusion with CD19+ CLL, and no patient with a CR has relapsed. Comparing responders to non-responders, there has been no association between response and patient age (66 vs 67 yrs), number of prior therapies (median 4 each), cell dose (7.5 vs 11.5 x 108MNC), or p53 mutation (3/8 vs 3/6, p>0.9), implying that within the dose ranges studied, there is no obvious dose:response relationship. All responding pts developed a delayed cytokine release syndrome (CRS), concurrent with peak T cell expansion, and was manifested by fever, and variable degrees of nausea, anorexia, myalgias, and transient hypotension and hypoxia. Detailed cytokine analysis showed marked increases from baseline values of IL6, IFN-γ, and IL2R, while no significant elevation in systemic levels of TNFα or IL2 were observed. The CRS required intervention in 5 patients. Treatment was initiated for hemodynamic or respiratory instability and was rapidly reversed in all cases with corticosteroids in 1 pt and the IL6-receptor antagonist tocilizumab (4 pts); 3 of these 4 pts also received 1 or 2 doses of corticosteroids. Persistence of CTL019 cells has been detected by flow cytometry in all 6 pts with ongoing responses 5-35 months after infusion, and all patients have sustained B cell aplasia without any unusual infectious complications. Conclusions CTL019 cells are autologous T cells genetically engineered to express an anti-CD19 scFv coupled to 4-1BB/CD3-ζ signaling domains. These cells can undergo robust in-vivo expansion and can persist for at least 3 yrs. CTL019 therapy is associated with a significant CRS that responds rapidly to anti-cytokine treatment. CTL019 cells can induce potent and sustained responses (8/14) for patients with advanced, relapsed and refractory CLL regardless of p53 mutation status. Disclosures: Porter: Novartis: Patents & Royalties, Research Funding; Genentech: Spouse employment, Spouse employment Other. Off Label Use: CTL019 cells to treat CLL. Kalos:Adaptive biotechnologies: Member scientific advisory board , Member scientific advisory board Other; Novartis corporation: CART19 technology, CART19 technology Patents & Royalties. Grupp:Novatis: Research Funding. Lledo:Novartis: Research Funding. Chew:Novartis: Patents & Royalties. Zheng:Novartis: Patents & Royalties. Levine:Novartis: cell and gene therapy IP, cell and gene therapy IP Patents & Royalties. June:Novartis: Patents & Royalties, Research Funding.

Effects of Oprozomib in Combination with Pomalidomide and/or Dexamethasone on Human Multiple Myeloma Tumors Growing in SCID Mice

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 5349-5349 ◽  
Author(s):  
Eric Sanchez ◽  
Mingjie Li ◽  
Abigail Gillespie ◽  
Puja Mehta ◽  
Suzie Vardanyan ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Tumor Size ◽  
Research Funding ◽  
Single Agent ◽  
Xenograft Model ◽  
Tumor Burden ◽  
Scid Mice ◽  
Human Multiple Myeloma ◽  
Minimal Reduction

Abstract Introduction: Oprozomib (OPZ) is an irreversible, orally administered proteasome inhibitor (PI).It decreases tumor burden and prevents tumor-related bone loss in preclinical multiple myeloma (MM) studies. In recently published clinical trials, the combination of the PI carfilzomib with the immunomodulatory agent (IMiD) lenalidomide and dexamethasone (Dex) has shown high response rates with durable responses for previously treated and untreated MM patients. Carfilzomib with the IMiD pomalidomide (Pom) and Dex for the treatment of RRMM patients shows promising results (Shah et al, 2013). We evaluated OPZ in combination with Pom and Dex using two of our human MM xenograft models in severe combined immunodeficient (SCID) mice. Methods: Each SCID mouse (n=10/group) was surgically implanted with a 20 - 40 mm3 MM tumor piece into the hind limb. Seven days post-implantation mice were randomized into treatment groups based on human immunoglobulin (Ig) G levels. OPZ stock solution (4 mg/ml) was diluted to 40 mg/kg using 1% carboxymethylcellulose (CMC) and administered twice weekly on two consecutive days via oral gavage.Dex stock solution (10 mg/ml) was diluted to 1 mg/kg using NaCl and administered daily via intraperitoneal injection.Pom stock solution (1 mg/ml) was diluted to 10 mg/kg using 1% CMC and administered daily via oral gavage. Tumor size was measured using calipers and IgG levels by ELISA. Results: Using our human MM model LAGk-1A, treatment with single agent OPZ or Pom produced a minimal reduction in tumor volume when compared with vehicle-treated mice, whereas Dex alone or OPZ + Pom produced more anti-MM effects, and no differences were observed between these two groups. Mice treated with OPZ + Dex or Pom + Dex also showed greater anti-MM activity than OPZ + Pom or Dex alone but the differences were not significant. All three agents together resulted in much smaller tumors when compared to OPZ + Pom on days 35, 42, 49 and 56 (P = 0.0006, P = 0.0001, P = 0.0002 and P < 0.0001, respectively). The same triplicate resulted in a smaller tumors when compared to OPZ + Dex on days 35, 42, 49, 56, and 63 (P = 0.0112, P = 0.0030, P = 0.0060, P = 0.0035 and P = 0.0021, respectively). Although Pom + Dex had some anti-MM effects when compared to the three single agents and one of the doublets (OPZ + Pom), mice receiving the triplicate demonstrated markedly smaller tumors when compared with Pom + Dex on days 35, 42, 49, 56, 63, 70, and 77 (P = 0.0250, P = 0.0018, P < 0.0001, P = 0.0014, P = 0.0018, P = 0.0017 and P = 0.0014, respectively). Mice receiving Pom + Dex had to be euthanized on day 77, whereas mice receiving all three drugs had very small tumors at study termination. We obtained similar results in a second MM xenograft model that produces IgG (LAGλ-1). Although day 21 post-tumor implantation mice receiving Pom alone had lower IgG levels compared with vehicle-treated mice (P = 0.0053), mice receiving OPZ + Pom had smaller tumors when compared to Pom alone (P = 0.0387), OPZ alone (P = 0.0004), or vehicle-treated mice (P = 0.0001). Although mice receiving Pom alone had a reduction in tumor size when compared with vehicle-treated mice (P = 0.0021), mice receiving OPZ + Pom had smaller tumors when compared with Pom alone (P = 0.0081), OPZ alone (P = 0.0007), or vehicle-treated mice (P < 0.0001). Mice receiving the triplicate showed smaller tumors on day 28 compared with mice treated with either the doublets of Pom + Dex (P = 0.0120) or OPZ + Pom (P = 0.0043). Conclusions: These in vivo human MM xenograft studies show that the combination of OPZ + Pom + Dex shows greater anti-MM activity than doublets (Pom + Dex, OPZ + Dex or OPZ + Pom) or single agents, and provides further support for this three drug combination to treat MM. Disclosures Tang: Onyx: Research Funding. [email protected]:Onyx: Consultancy, Honoraria, Research Funding, Speakers Bureau.

IL1RAP Antibodies Block IL1-Induced Expansion of Primitive CML Cells and Display Therapeutic Effects in Xenograft Models

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 1118-1118
Author(s):  
Helena Ågerstam ◽  
Nils Hansen ◽  
Sofia Von Palffy ◽  
Carl Sandén ◽  
Kristian Reckzeh ◽  
...  
Keyword(s):  
Stem Cells ◽  
Research Funding ◽  
Effector Cell ◽  
Leukemic Cells ◽  
Nsg Mice ◽  
Xenograft Models ◽  
Equity Ownership ◽  
In Vivo Effects

Abstract Chronic myeloid leukemia (CML) is currently treated with tyrosine kinase inhibitors (TKIs) but these do not effectively eliminate the CML stem cells. As a consequence, CML stem cells persist and cause relapse in most patients upon drug discontinuation. Furthermore, no effective therapy exists for the advanced stages of the disease. Thus, there is still a need for novel treatment strategies in CML. We have previously shown that Interleukin 1 receptor accessory protein (IL1RAP), a co-receptor of IL1R1, is highly expressed on primitive CML cells and that a polyclonal IL1RAP antibody can direct natural killer (NK) cells to specifically target and destroy CD34+CD38- CML cells in an in vitro-based antibody dependent cell-mediated cytotoxicity (ADCC) assay (Järås et al, PNAS, 2010). The aim of the present study was to investigate the consequences of IL1RAP expression on primitive CML cells and the in vivo therapeutic efficacy of monoclonal IL1RAP antibodies against CML cells. Primary chronic phase (CP) CD34+ CML cells were cultured in medium supplemented with cytokines known to signal through receptor complexes involving IL1RAP. The addition of IL1 to the cultures resulted in a marked cellular expansion specifically for the primitive CD34+CD38- CML cells. Moreover, the CD34+CD38- cells showed phosphorylation of the downstream mediator of IL1-signaling NFKB. RNA-sequencing confirmed the activation of NFKB and of genes involved in cell cycling, indicating that IL1 stimulation of CD34+CD38- CML cells induced proliferation. Upon addition of an IL1RAP antibody capable of blocking IL1-signaling to the suspension cultures, the IL1-induced expansion and NFKB phosphorylation of CD34+CD38- CML cells was suppressed. Interestingly, both the IL1RAP expression and the response to IL1 as measured by NFKB phosphorylation was retained during TKI treatment of the cells. To assess the in vivo effects of IL1RAP antibodies in CML models, we first engrafted NOD/SCID mice with BCR/ABL1 expressing BV173 cells and treated the mice with the monoclonal IL1RAP antibody mAb81.2. Mice receiving treatment with mAb81.2 displayed a prolonged survival compared to controls, accompanied by reduced levels of leukemic cells in the BM. In vitro studies showed that mAb81.2 lacked a direct effect on cellular expansion or apoptosis. Instead, the IL1RAP antibody could direct NK cells to elicit killing of the leukemic cells, thereby suggesting effector cell mediated mechanisms to be an important in vivo mode-of-action. To validate the in vivo effects on primary CML cells, we next engrafted CP or blast phase (BP) CML cells into immunodeficient mice. Following engraftment of CP CD34+ CML cells into NSG mice and subsequent treatment with mAb81.2, a reduction of human myeloid cells was observed, suggesting that the treatment targeted the leukemic graft. Importantly, mAb81.2 treatment also reduced the levels of candidate CD34+CD38-IL1RAP+ CML stem cells. Finally, BP CML cells were engrafted into NOD/SCID mice that have a more intact effector cell function compared to NSG mice. Following treatment with mAb81.2 a significant reduction of leukemic cells in the BM as well as in the periphery was observed compared to control mice. Importantly, secondary transplantations revealed a therapeutic effect also on the BP CML stem cells. In vitro ADCC assays confirmed that CML BP cells, including a sample with the highly TKI-resistant T315I mutation, could be targeted and killed using mAb81.2. We conclude that IL1RAP antibodies can suppress IL1-induced expansion of primitive CML cells and that in vivo administration of IL1RAP antibodies in CML xenograft models has anti-leukemic effects that extend to the CML stem cells. These results show that an antibody-based therapy against IL1RAP can be used to efficiently target CML stem cells. Disclosures Richter: BMS: Honoraria, Research Funding; Pfizer: Honoraria, Research Funding; Ariad: Honoraria, Research Funding; Novartis: Honoraria, Research Funding. Järås:Cantargia AB: Equity Ownership. Fioretos:Cantargia AB: Equity Ownership.

scholarly journals ATR addiction in multiple myeloma: synthetic lethal approaches exploiting established therapies

Haematologica ◽  
2019 ◽  
Vol 105 (10) ◽  
pp. 2440-2447 ◽  
Author(s):  
Oronza A. Botrugno ◽  
Silvia Bianchessi ◽  
Desirée Zambroni ◽  
Michela Frenquelli ◽  
Daniela Belloni ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Cell Proliferation ◽  
Synthetic Lethality ◽  
Ex Vivo ◽  
Myeloma Cell ◽  
Tumor Burden ◽  
In Vivo Models ◽  
Cancer Multiple

Therapeutic strategies designed to tinker with cancer cell DNA damage response have led to the widespread use of PARP inhibitors for BRCA1/2-mutated cancers. In the haematological cancer multiple myeloma, we sought to identify analogous synthetic lethality mechanisms that could be leveraged upon established cancer treatments. The combination of ATR inhibition using the compound VX-970 with a drug eliciting interstrand cross-links, melphalan, was tested in in vitro, ex vivo, and most notably in vivo models. Cell proliferation, induction of apoptosis, tumor growth and animal survival were assessed. The combination of ATM inhibition with a drug triggering double strand breaks, doxorucibin, was also probed. We found that ATR inhibition is strongly synergistic with melphalan, even in resistant cells. The combination was dramatically effective in targeting myeloma primary patient cells and cell lines reducing cell proliferation and inducing apoptosis. The combination therapy significantly reduced tumor burden and prolonged survival in animal models. Conversely, ATM inhibition only marginally impacted on myeloma cell survival, even in combination with doxorucibin at high doses. These results indicate that myeloma cells extensively rely on ATR, but not on ATM, for DNA repair. Our findings posit that adding an ATR inhibitor such as VX-970 to established therapeutic regimens may provide a remarkably broad benefit to myeloma patients.

The antihelmintic flubendazole inhibits microtubule function through a mechanism distinct from Vinca alkaloids and displays preclinical activity in leukemia and myeloma

Blood ◽  
2010 ◽  
Vol 115 (23) ◽  
pp. 4824-4833 ◽  
Author(s):  
Paul A. Spagnuolo ◽  
Jiayi Hu ◽  
Rose Hurren ◽  
Xiaoming Wang ◽  
Marcela Gronda ◽  
...  
Keyword(s):  
Tumor Growth ◽  
Xenograft Model ◽  
Toxicity Testing ◽  
Myeloma Cell ◽  
Microtubule Inhibitor ◽  
P Glycoprotein ◽  
A Site ◽  
Microtubule Function

Abstract On-patent and off-patent drugs with previously unrecognized anticancer activity could be rapidly repurposed for this new indication given their prior toxicity testing. To identify such compounds, we conducted chemical screens and identified the antihelmintic flubendazole. Flubendazole induced cell death in leukemia and myeloma cell lines and primary patient samples at nanomolar concentrations. Moreover, it delayed tumor growth in leukemia and myeloma xenografts without evidence of toxicity. Mechanistically, flubendazole inhibited tubulin polymerization by binding tubulin at a site distinct from vinblastine. In addition, cells resistant to vinblastine because of overexpression of P-glycoprotein remained fully sensitive to flubendazole, indicating that flubendazole can overcome some forms of vinblastine resistance. Given the different mechanisms of action, we evaluated the combination of flubendazole and vinblastine in vitro and in vivo. Flubendazole synergized with vinblastine to reduce the viability of OCI-AML2 cells. In addition, combinations of flubendazole with vinblastine or vincristine in a leukemia xenograft model delayed tumor growth more than either drug alone. Therefore, flubendazole is a novel microtubule inhibitor that displays preclinical activity in leukemia and myeloma.

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