Cytotoxic effect in vivo and in vitro of CHS 828 on human myeloma cell lines

Abstract As with other B-cell malignancies, chromosomal translocations to the immunoglobulin heavy-chain (IgH) locus on chromosome 14q32 are believed to be a hallmark of multiple myeloma (MM), occurring in approximately 50% of patients. Identification of these chromosomal translocations has resulted in the discovery of powerful prognostic tools and novel molecular targets that promise to revolutionize the treatment of this malignancy. Five recurrent translocation partners have been defined, resulting in the dysregulation of the genes encoding cyclin D1 and D3, c-maf, mafB and Fibroblast Growth Factor Receptor 3 (FGFR3) together with MMSET. Genetic analysis of 14q32 translocations in MM has identified distinct groups of patients with separate clinical outcomes supporting a biological correlation of these genes in MM. In particular, the t(4;14) translocation portends a particularly bad prognosis. The association of FGFR3 expression with t(4;14) myeloma and the demonstration of the transforming potential of this receptor tyrosine kinase (RTK), make this a particularly attractive target for drug development for this poor prognosis group. We report here the development of a novel and highly specific anti-FGFR3 neutralizing antibody (PRO-001) isolated from a phage display human combinatorial antibody library. PRO-001 binds with high affinity (Kd=1.3 nM) to FGFR3 in in vitro binding assays and blocks ligand-dependent and independent FGFR3 phosphorylation and signal transduction in cell-based assays. Furthermore, PRO-001 potently inhibits FGFR3-dependent solid tumor growth in mouse xenograft models. We found that PRO-001 bound to, and competed with FGF binding to the surface of FGFR3 on human myeloma cell lines. PRO-001 inhibited FGF-induced phosphorylation of wild-type FGFR3 and downstream ERK phosphorylation in stable B9 cell transfectants (B9-WT) and FGFR3 expressing human myeloma cell lines. The antibody inhibited FGF-mediated growth of B9-WT with an IC50 of 3 μg/ml as determined by MTT proliferation assay. Growth of these cells could be rescued by IL-6 demonstrating selectivity of PRO-001 for FGFR3. PRO-001 inhibited the viability of the FGFR3 expressing, human myeloma cell line, UTMC2. Inhibition of viability was still observed when cells were co-cultured with stroma or in the presence of IL-6, a potent growth factor for MM cells. Several myeloma cell lines lacking FGFR3, showed minimal growth inhibition demonstrating selectivity and lack of non-specific toxic at effective dose concentrations. Finally, PRO-001 bound to FGFR3 on the cell surface, inhibited ERK phosphorylation, and induced cytotoxic responses in primary MM samples derived from t(4;14) positive patients. A xenograft mouse model has been established and studies assessing in vivo activity of PRO-001 are planned and will be reported. Taken together, the data demonstrate that PRO-001 is a specific and potent inhibitor of FGFR3 and that it deserves further study for targeted therapy in MM.

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Retinoic acid modulates the in vivo and in vitro growth of IL-6 autocrine human myeloma cell lines via induction of apoptosis

Clinical & Experimental Immunology ◽

10.1046/j.1365-2249.1996.d01-637.x ◽

1996 ◽

Vol 104 (1) ◽

pp. 167-172 ◽

Cited By ~ 26

Author(s):

Y. LEVY ◽

S. LABAUME ◽

M. COLOMBEL ◽

J. C. BROUET

Keyword(s):

Retinoic Acid ◽

Cell Lines ◽

Myeloma Cell ◽

In Vitro Growth ◽

Induction Of Apoptosis ◽

Human Myeloma Cell

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

Blood ◽

10.1182/blood.v122.21.3493.3493 ◽

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.

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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 ◽

10.1182/blood.v124.21.5722.5722 ◽

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.

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Effect of the green tea polyphenol epigallocatechin gallate (EGCG) on growth and IL-6 signalling pathways in malignant plasma cells

Journal of Clinical Oncology ◽

10.1200/jco.2007.25.18_suppl.8114 ◽

2007 ◽

Vol 25 (18_suppl) ◽

pp. 8114-8114

Author(s):

R. Burger ◽

H. Czekalla ◽

K. Richter ◽

T. Ahrens ◽

A. Guenther ◽

...

Keyword(s):

Cell Lines ◽

Green Tea ◽

Epigallocatechin Gallate ◽

Myeloma Cell ◽

Signalling Pathways ◽

Dependent Manner ◽

Green Tea Polyphenol ◽

Dose Dependent ◽

Human Myeloma Cell

8114 Background: Epigallocatechin gallate (EGCG) is the predominant polyphenolic constituent of green tea leaves that possesses antitumor, antiinflammatory, and antioxidant activity. EGCG exerts its effects through potentially multiple mechanisms including inhibition of growth factor receptor signalling. The compound is currently under investigation in a phase I/II clinical trial for treatment of patients with early stage chronic lymphocytic leukemia at Mayo Clinic. The goal of our study was to examine the in vitro effects of EGCG in multiple myeloma (MM). Methods: A panel of human myeloma cell lines (n=6) including the IL-6 dependent INA-6 cell line was used to evaluate the sensitivity to EGCG. Cells were cultured for three days in the absence or presence of EGCG at concentrations between 6.25 μM and 100 μM. Cell viability was determined in a colorimetric tetrazolium (MTS) based assay and by trypanblue exclusion. For signalling experiments, INA-6 cells were IL-6 and serum starved and then treated with EGCG for two hours before IL-6 was added. Whole cell lysates were prepared and subjected to SDS-PAGE and Western blot analysis. Results: EGCG inhibited the in vitro growth of human myeloma cell lines by inducing cell death in a time and dose-dependent manner. IC50 concentrations were between 12,5 μM and 50 μM. IL-6 mediated growth of INA-6 cells was inhibited at similar doses. The addition of excess amounts of IL-6 could not protect from EGCG induced cytotoxicity. Pretreatment of INA-6 cells with EGCG resulted in a dose-dependent inhibition of IL-6 induced STAT3 tyrosine phosphorylation. In these cells, stimulation with IL-6 leads to upregulation of Mcl-1 expression. In contrast, phosphorylation of p44/p42 MAPK, which is constitutively activated in INA-6 cells, was not affected. Conclusion: EGCG has growth inhibitory activity on myeloma cells. Specific inhibition of signalling pathways that regulate expression of anti-apoptotic proteins could be one mechanism how EGCG exerts its activity. Our work provides the rationale for further studies to evaluate the effect of EGCG not only in B-CLL, but also in plasma cell tumors. No significant financial relationships to disclose.

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Effect of a novel agent, SL-401, targeting interleukin-3 (IL-3)-receptor on plasmacytoid dendritic cell (pDC)-induced myeloma cell growth and drug resistance.

Journal of Clinical Oncology ◽

10.1200/jco.2013.31.15_suppl.8582 ◽

2013 ◽

Vol 31 (15_suppl) ◽

pp. 8582-8582

Author(s):

Dharminder Chauhan ◽

Arghya Ray ◽

Christopher Brooks ◽

Eric K. Rowinsky ◽

Kenneth Carl Anderson

Keyword(s):

Drug Resistance ◽

Cell Growth ◽

Cell Lines ◽

Plasmacytoid Dendritic Cell ◽

Myeloma Cell ◽

Healthy Donors ◽

Signaling Axis ◽

Novel Therapeutic Strategies

8582 Background: Multiple myeloma (MM) remains incurable despite novel therapies, highlighting the need for further identification of factors mediating disease progression and drug resistance. The bone marrow (BM) microenvironment confers growth, survival, and drug resistance in MM cells. Our recent study utilized in vitro and in vivo MM xenograft models to show that plasmacytoid dendritic cells (pDCs) were significantly increased in MM BM and promote MM growth (Chauhan et al., Cancer Cell 2009, 16:309). Importantly, we found increased IL-3 levels upon pDC-MM interaction, which in turn, trigger MM cell growth and pDCs survival. IL-3R is highly expressed on pDCs. We utilized SL-401, a novel biologic conjugate that targets IL-3R, to examine whether abrogation of IL-3–IL-3R signaling axis affects pDC-MM interaction and its tumor promoting sequelae. Methods: MM cell lines, patient MM cells, and pDCs from healthy donors or MM patients were utilized to study the anti-MM activity of SL-401. MM cells and pDCs were cultured alone or together in the presence or absence of SL-401, followed by analysis of cell growth or viability. Results: SL-401 significantly decreased the viability of pDCs at low concentrations (IC50: 0.83 ng/ml; P < 0.005, n = 3). SL-401 also decreased the viability of MM cells at clinically achievable doses. Co-culture of pDCs with MM cells induced growth of MM cell lines; and importantly, low doses (0.8 ng/ml) of SL-401 blocked MM cell growth-promoting activity of pDCs. MM patient-derived pDCs induced growth of MM cell lines and primary MM cells as well; conversely, SL-401 inhibited pDC-triggered MM cell growth (P < 0.005, n= 5). Tumor cells from 3 of the 5 patients were from patients whose disease was progressing while on bortezomib, dexamethasone, and lenalidomide therapies. In agreement with these results, SL-401 blocked pDC-induced growth of dexamethasone-resistant MM cell lines. Conclusions: Our study therefore provides the basis for directly targeting pDCs or blocking the pDC-MM interaction, as well as targeting MM, in novel therapeutic strategies with SL-401 to enhance MM cytotoxicity, overcome drug-resistance, and improve patient outcome.

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Expression and in Vitro Binding of Protease Activated Receptor1 (PAR1) with Novel Anti-PAR1 Molecules: Data on Fresh Myeloma Marrow Plasma Cells and Human Myeloma Cell Lines

Blood ◽

10.1182/blood.v126.23.4440.4440 ◽

2015 ◽

Vol 126 (23) ◽

pp. 4440-4440

Author(s):

Meral Beksac ◽

Pinar Ataca ◽

Berna Atesagaoglu ◽

Klara Dalva ◽

Andry Nur Hidayat ◽

...

Keyword(s):

Board Of Directors ◽

Cell Lines ◽

Research Funding ◽

Plasma Cells ◽

Myeloma Cell ◽

Lower Percentage ◽

Advisory Committees ◽

In Silico Docking ◽

Human Myeloma Cell

Abstract Introduction and Aim: Myeloma plasma cells are dependent on stromal support which is mediated through cell adhesion. Heparanase activity has been shown to be associated with aggressive behavior or Bortezomib resistance and can lead to increased levels of proteases as well as shedding of heparan sulfate proteoglycan syndecan-1(CD138) from myeloma cells. We have recently published in vivo anti-myeloma effects of low molecular weight heparin (Beksac et al Acta Haematol 2015). Protease activated Receptor (PAR1) is a thrombin receptor. PAR1 gene and antigen expression on myeloma patient samples and cell lines (HMCL) has been recently reported by University of Arkansas (UAMS) group (Tian et al ASH 2011). They were able to find HMCLs H929, U266, JJN3 to express PAR1. Also expression was found to be highest among patients with 5q amplification where the PAR1 gene is located. Patients and Methods: We analyzed PAR1 expression (WEDE15 PE, Beckman Coulter) by flow cytometry, on CD38+CD138+/-CD27+/- cells obtained from fresh patient bone marrow samples obtained either at diagnosis (n: 84)(NDMM) or relapse (n: 54)(RRMM) and were compared with marrow samples taken from patients without MM (n: 43). Our group in Ankara University had previously synthesized and published novel benzamide and phenyl acetamide derivatives. We performed an in silico docking analysis on these molecules, and eleven (TD10,TD12,TD12A,TD12B,TD13,TD14,TD14B,XT2,XT2B,XT5,XT11) were found to bind to PAR1. These molecules were screened using 72 hour MTT assay on primary and refractory cell lines (U266BR ,U266, JJN3BR, JJN3, H929R, OPM2, OPM2R, KMS28PE). Results: PAR1 expression was highest on platelets followed by myeloma plasma cells (0-81.9%) and did not correlate with ISS. PAR1 expression (Threshold: >2.5 % or >5%) could be detected in NDMM (35 % or 14%) and RRMM (31% or 19%) of patients (Table1). PAR1+CD38+138+ cells were more frequent among patients with lower percentage of plasma cells in RRMM group (2,98 ± 4,5 vs 1,93 ± 3,96, P=0.028) but not NDMM. PAR1 was similarly highly expressed on HCML. Two of the novel PAR1 binding molecules (XT5 and XT2B) were found to have the lowest IC50. The IC50 were similar for all HMCLs, primary and refractory, with XT5. With XT2B the IC50 was less (U266) or higher (JJN3) or similar (OPM2) for refractory compared to the primary HMCL. PAR1 expression and anti-myeloma IC50 values of cell lines are summarized in Table 2. Conclusion: PAR1 expression is detectable at very low or very high percentages on CD138+plasma cells. Expression is higher on cells with CD27 expression (patient samples) or lacking CD27 (HMCL). Inverse correlation between PAR1 expression and plasma cell percentage among myeloma patients is detected among RRMM but not on NDMM samples. This finding may point to expression of PAR1 on quiescent plasma progenitors as suggested by Tian et al previously. The intensity or frequency of PAR1 expression on HMCL did not influence the anti-myeloma effects of these novel molecules. PAR1 binding molecules, in particular XT5, are promising as they are effective even on Bortezomib refractory HCML. However their mechanism of action and the role of PAR1 require further investigations. This study has been supported by a research grant from Turkish Academy of Sciences. Table 1. Frequency of PAR1 expression (> 2.5 %) on total plasma cells (CD38+138+) and on quiescent plasma cells (CD38+138+27+) Control (n=43) NDMM (n=84) RRMM (n=54) P CD38+138+ (%) 0,56± 0,66 4,48 ± 7,67 5,44 ± 12,13 0,007 PAR1+ among CD38+138 (%) 6,18 ± 13,14 4,14 ± 11,00 3,42 ± 8,81 0,394 PAR1+ among CD38+138+27+(%) 5,44 ± 12,13 3,42 ± 8,81 3,58 ± 8,57 0,207 Table 1. Comparison of Flow Cytometric PAR1 expression and IC50 (in uM after 72 hours)of the two novel molecules on three Human Myeloma Cell Lines. H929 RPMI8221 U266 IC50 XT2B 33.9 >100 34.3 IC50 XT5 8.12 5.45 9.77 CD38+138+ (total%) 85 % 75 % 80 % PAR1% and (MFI) within CD38+138+ 83 %(13,6) 90 % (2,1) 85 % (2,1) Disclosures Beksac: Celgene: Consultancy, Speakers Bureau; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen-Cilag: Consultancy, Speakers Bureau; Bristol-Myers Squibb: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Off Label Use: Elotuzumab is an investigational agent being studied for the treatment of multiple myeloma.. Usmani:Millennium: Honoraria, Speakers Bureau; Sanofi: Honoraria, Research Funding; Onyx: Honoraria, Research Funding, Speakers Bureau; Celgene: Honoraria, Speakers Bureau; Array BioPharma: Honoraria, Research Funding; Pharmacyclics: Research Funding; Janssen Oncology: Honoraria, Research Funding. Tian:University of Arkansas for Medical Sciecnes: Employment.

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Cytotoxic effect of Montivipera bornmuelleri’s venom on cancer cell lines: in vitro and in vivo studies

PeerJ ◽

10.7717/peerj.9909 ◽

2020 ◽

Vol 8 ◽

pp. e9909

Author(s):

Carol Haddoub ◽

Mohamad Rima ◽

Sandrine Heurtebise ◽

Myriam Lawand ◽

Dania Jundi ◽

...

Keyword(s):

Tumor Growth ◽

Cell Lines ◽

Cytotoxic Effect ◽

In Vivo Studies ◽

Dependent Manner ◽

In Vivo Testing ◽

Murine Fibrosarcoma ◽

Dose Dependent

Background Montivipera bornmuelleri’s venom has shown immunomodulation of cytokines release in mice and selective cytotoxicity on cancer cells in a dose-dependent manner, highlighting an anticancer potential. Here, we extend these findings by elucidating the sensitivity of murine B16 skin melanoma and 3-MCA-induced murine fibrosarcoma cell lines to M. bornmuelleri’s venom and its effect on tumor growth in vivo. Methods The toxicity of the venom on B16 and MCA cells was assessed using flow cytometry and xCELLigence assays. For in vivo testing, tumor growth was followed in mice after intratumoral venom injection. Results The venom toxicity showed a dose-dependent cell death on both B16 and MCA cells. Interestingly, overexpression of ovalbumin increased the sensitivity of the cells to the venom. However, the venom was not able to eradicate induced-tumor growth when injected at 100 µg/kg. Our study demonstrates a cytotoxic effect of M. bornmuelleri’s venom in vitro which, however, does not translate to an anticancer action in vivo.

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Mcl-1 Is Overexpressed in Multiple Myeloma and Correlates with Disease Severity.

Blood ◽

10.1182/blood.v104.11.1419.1419 ◽

2004 ◽

Vol 104 (11) ◽

pp. 1419-1419

Author(s):

Soraya Wuilleme-Toumi ◽

Nelly Robillard ◽

Patricia Gomez-Bougie ◽

Philippe Moreau ◽

Steven Le Gouill ◽

...

Keyword(s):

Multiple Myeloma ◽

Bone Marrow ◽

Disease Severity ◽

Cell Lines ◽

Plasma Cells ◽

Myeloma Cell ◽

Lymphocytic Leukemia ◽

Myeloma Cells

Abstract Multiple Myeloma (MM) is a fatal malignancy of B-cell origin characterized by the accumulation of plasma cells within the bone marrow. The expression of the pro-survival members of the Bcl-2 family has been shown to be a key process in the survival of myeloma cells. More particularly, Mcl-1 expression turned out to be critical for their survival. Indeed, knockdown of Mcl-1 by antisenses induces apoptosis in myeloma cells. Finally, Mcl-1 was found to be the only anti-apoptotic Bcl-2 family member which level of expression was modified by cytokine treatment of myeloma cells. For these reasons, we have evaluated the expression of Mcl-1 in vivo in normal, reactive and malignant plasma cells (PC) i.e., myeloma cells from 55 patients with MM and 20 human myeloma cell lines using flow cytometry. We show that Mcl-1 is overexpressed in MM in comparison with normal bone marrow PC. Forty-seven percent of patients with MM at diagnosis (p=.017) and 80% at relapse (p=.014 for comparison with diagnosis) overexpress Mcl-1. Of note, only myeloma cell lines but not reactive plasmocytoses have abnormal Mcl-1 expression, although both plasmocyte expansion entities share similar high proliferation rates (>20%). Of interest, Bcl-2 as opposed to Mcl-1, does not discriminate malignant from normal PC. This shows that the overexpression of Mcl-1 is clearly related to malignancy rather than to proliferation. It will be important to know whether the overexpression of Mcl-1 is related to an abnormal response to cytokines like Interleukin-6 or to mutations of the promoter of the Mcl-1 gene as already described in B chronic lymphocytic leukemia. Finally, level of Mcl-1 expression is related to disease severity, the highest values being correlated with the shortest event-free survival (p=.01). In conclusion, Mcl-1 which has been shown to be essential for the survival of human myeloma cells in vitro is overexpressed in vivo in MM and correlates with disease severity. Mcl-1 represents a major therapeutical target in MM.

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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 ◽

10.1182/blood.v104.11.2470.2470 ◽

2004 ◽

Vol 104 (11) ◽

pp. 2470-2470 ◽

Cited By ~ 1

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.

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