A Small-Molecule Suppressant of Survivin YM155 Induces Cell Death Via Proteasomal Degradation of c-Myc in Multiple Myeloma Cells

Abstract [Background] Survivin is a member of the inhibitor of apoptosis protein (IAP) family with its dual roles in mitosis and apoptosis, and emerges as an attractive target for cancer therapy. YM155, a novel molecular targeted agent, suppresses survivin, which is overexpressed in many tumor types. However, the effect of this agent on multiple myeloma (MM) cells remains unclear. [Materials & Methods] Five human MM cell lines, RPMI8226, U266, KMS20, KMS28PE, and KMS34 were used in this study. Cell proliferation and cell death were evaluated by MTT assay and by flow cytometric analysis with annexin V/PI staining. Gene and protein expressions were analyzed with quantitative PCR (qPCR) and immunoblot, respectively. For proteasome inhibitory assay, cells were treated with YM155 and/or proteasome inhibitor MG132 for 6 hours. [Results] YM155 inhibited cell proliferation of these cells in a dose- and time-dependent manner. Annexin V assay showed that YM155 induced apoptosis in these cells. To better understand these effects of YM155 on MM cells, we evaluated the intracellular signaling and apoptosis-associated protein status. Immunoblot analyses showed that YM155 reduced not only survivin but also Mcl-1 and XIAP expressions. We also observed the activation of caspase-3 and PARP in YM155-treated cells, indicating that YM155 induces caspase-dependent apoptosis. In contrast, YM155 did not affect phosphorylation status of Erk1/2 and STAT3. Interestingly, YM155 suppressed c-Myc and IRF4 protein expressions, both of which are recognized as an important transcription factor in the pathogenesis of MM. In addition, qPCR assay showed that YM155 treatment did not reduce c-Myc mRNA level. On the other hand, proteasome inhibitor prevented the suppression of c-Myc expression by YM155 treatment, indicating a proteasomal degradation of c-Myc by YM155. [Conclusion] YM155 suppresses cell proliferation and survival in MM cells in part via not only inhibiting anti-apoptotic proteins such as survivin, Mcl-1 and XIAP but also suppressing c-Myc oncoprotein expression. Further study is needed to clarify the molecular mechanism of c-Myc degradation induced by YM155. Our results may provide a new concept in c-Myc-targeting therapy for MM because c-Myc oncoprotein have been considered undruggable. Disclosures Ishida: Bristol-Myers Squibb: Honoraria.

Download Full-text

Apo2L/TRAIL and Bcl-2–related proteins regulate type I interferon–induced apoptosis in multiple myeloma

Blood ◽

10.1182/blood.v98.7.2183 ◽

2001 ◽

Vol 98 (7) ◽

pp. 2183-2192 ◽

Cited By ~ 138

Author(s):

Quan Chen ◽

Bendi Gong ◽

Ashraf S. Mahmoud-Ahmed ◽

Aimin Zhou ◽

Eric D. Hsi ◽

...

Keyword(s):

Multiple Myeloma ◽

Cell Death ◽

Cytochrome C ◽

Plasma Cells ◽

Annexin V ◽

Dominant Negative ◽

Type I ◽

Dependent Manner ◽

Cytochrome C Release ◽

Apoptotic Pathway

It has been reported that interferons (IFNs) may have antitumor activity in multiple myeloma (MM). The mechanism for their effect on MM, however, remains elusive. This study shows that IFN-α and -β, but not -γ, induce apoptosis characterized by Annexin V positivity, nuclear fragmentation and condensation, and loss of clonogenicity in 3 MM cell lines (U266, RPMI-8266, and NCI-H929), and in plasma cells from 10 patients with MM. Apo2 ligand (Apo2L, also TRAIL) induction was one of the earliest events following IFN administration in U266 cells. Treatment of these cells with TRAIL, but not with Fas agonistic antibodies, induces apoptosis. Cell death induced by IFNs and Apo2L in U266 cells was partially blocked by a dominant-negative Apo2L receptor, DR5, demonstrating the functional significance of Apo2L induction. This study shows that IFNs activate caspases and the mitochondrial-dependent apoptotic pathway, possibly mediated by Apo2L production. Thus, IFN-α and -β induce cytochrome c release from mitochondria starting at 12 hours, with an amplified release seen at 48 hours. Moreover, Bid cleavage precedes the initial cytochrome c release, whereas the late, amplified cytochrome c release coincides with changes in levels of Bcl-2, Bcl-XL, and reduction of mitochondrial membrane potential. These results link the Apo2L induction and modulation of Bcl-2 family proteins to mitochondrial dysfunction. Furthermore, IFNs and Apo2L induce cell death of CD38+/CD45−/dimplasma cells, without significant effect on nonplasma blood cells, in a caspase and Bcl-2 cleavage-dependent manner. These results warrant further clinical studies with IFNs and Apo2L in MM.

Download Full-text

Daratumumab Directly Induces Human Multiple Myeloma Cell Death and Acts Synergistically with Conventional and Novel Anti-Myeloma Drugs

Blood ◽

10.1182/blood.v116.21.3013.3013 ◽

2010 ◽

Vol 116 (21) ◽

pp. 3013-3013

Author(s):

Sun-Young Kong ◽

Xian-Feng Li ◽

Sabikun Nahar ◽

Weihua Song ◽

Michel de Weers ◽

...

Keyword(s):

Multiple Myeloma ◽

Cell Death ◽

Cell Viability ◽

Caspase 3 ◽

Annexin V ◽

Dependent Manner ◽

Cell Viability Assay ◽

Viability Assay ◽

Synergistic Cytotoxicity ◽

Dose Dependent

Abstract Abstract 3013 Daratumumab is a novel fully human therapeutic CD38-specific monoclonal antibody (mAb) that is currently in phase I/II safety and dose finding clinical studies in MM. We recently demonstrated that daratumumab induces antibody dependent cytotoxicity (ADCC) and complement dependent cytotoxicity (CDC) against multiple myeloma (MM) cells (ASH Abstract #608, 2009). Significantly, daratumumab induces ADCC-mediated autologous lysis against MM patient cells. In addition, when cross-linked, daratumumab directly induces Ramos lymphoma cell death. We here studied whether daratumumab directly kills MM cells and whether daratumumab could be combined with other anti-MM drugs to further enhance its direct cytotoxicity. Direct daratumumab-induced MM cell death was determined using CellTiter-Glo luminescent cell viability assay and Annexin V/PI flow cytometry analysis, with or without goat anti-human IgG crosslinking. Following 48h incubation, daratumumab (0.1-10 μg/ml), when cross-linked, directly induced cytoxicity against dexamethasone (dex)-sensitive MM1S and dex-resistant MM1R cells, as evidenced by decreased cell viability in a dose-dependent manner. Importantly, cross-linked daratumumab increased caspase 3/7 activities in a dose-dependent fashion, as assessed by the Caspase-Glo® 3/7 luminescence assay. Furthermore, daratumumab upregulated Annexin V+ and Annexin V+/PI+ cells in freshly isolated CD138+ MM patient cells, from 7.7% to 20.6% and 10.9% to 15.4 %. Therefore, cross-linked daratumumab can directly trigger apoptosis of patient myeloma cells. Cell viability assay was further performed on MM1S cells when daratumumab (0.1, 1, 10 μg/ml) was combined with dex (0.5 and 1 μM) or bortezomib (2.5, 5, and 10 nM). Following 48–72h incubation with daratumumab, both dex and bortezomib synergistically inhibited MM cell viability, as determined by combination index (CI) < 0.5 at given combined concentrations of these drugs. Enhanced caspase 3/7 activation was also seen when daratumumab was combined with dex. To evaluate combination cytotoxicity induced by lenalidomide with daratumumab, peripheral blood mononuclear effector cells (PBMCs) from normal donors (n=2) were pretreated with lenalidomide (2 μM) for 3 days followed by daratumumab-mediated ADCC assays against MM1S cells. Using calcein-AM release measurements, lenalidomide-pretreated PBMCs further augmented daratumumab-induced MM1S cell lysis, whereas daratumumab-pretreated PBMCs did not alter ADCC. Taken together, our studies show that daratumumab directly induces MM cell death via activation of caspase 3/7 and daratumumab induced synergistic cytotoxicity with dex or bortezomib. Moreover, lenalidomide augments daratumumab-induced ADCC against MM cells. These results further support combination clinical trials of conventional and novel anti-MM drugs with daratumumab in MM. Disclosures: Weers: Genmab: Employment. Parren:Genmab: Employment. Richardson:Keryx Biopharmaceuticals: Honoraria. Munshi:Millennium Pharmaceuticals: Honoraria, Speakers Bureau. Anderson:Millennium Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau.

Download Full-text

YM155, a Survivin Suppressant, Induces Cell Death Via Suppression Of c-Myc Expression In Multiple Myeloma Cells

Blood ◽

10.1182/blood.v122.21.1667.1667 ◽

2013 ◽

Vol 122 (21) ◽

pp. 1667-1667

Author(s):

Shigeki Ito ◽

Maki Asahi ◽

Ryousei Sasaki ◽

Tatsuo Oyake ◽

Hideto Tamura ◽

...

Keyword(s):

Multiple Myeloma ◽

Cell Lines ◽

Intracellular Signaling ◽

Conflicts Of Interest ◽

Mrna Level ◽

Inhibitor Of Apoptosis ◽

Dependent Manner ◽

Myeloma Cells ◽

Inhibitor Of Apoptosis Protein ◽

Apoptosis Protein

Abstract Survivin is a member of the inhibitor of apoptosis protein (IAP) family with its dual roles in mitosis and apoptosis, and emerges as an attractive target for cancer therapy. Recent reports have demonstrated that survivin overexpression is associated with drug resistance and poor outcome in hematological malignancy including multiple myeloma (MM). YM155, a novel molecular targeted agent, suppresses survivin through the inhibition of transcription. However, the effect of this agent on MM cells has not been elucidated. In this study, we investigated the effect of YM155 on proliferation and survival of five human MM cell lines. YM155 inhibited the proliferation of these cells in a dose- and time-dependent manner (IC50 = 10 nM in 3 and 100 nM in 2 cell lines, respectively). Annexin V assay showed that YM155 induced apoptosis in these cells. To better understand these effects of YM155 on MM cells, we evaluated the intracellular signaling and apoptosis-associated protein status. Immunoblot analyses showed that YM155 reduced not only survivin but also myeloid cell leukemia sequence 1 (Mcl-1) and X-linked inhibitor of apoptosis protein (XIAP) expression. We also observed the activation of caspase-3 and poly(ADP-ribose) polymerase in YM155-treated cells, indicating that YM155 induces caspase-dependent apoptosis. YM155 did not affect phosphorylation status of Erk1/2 and STAT3. Interestingly, we found that YM155 suppressed c-Myc and interferon regulatory factor 4 (IRF4) expression, both of which are recognized as an important oncogene in the pathogenesis of MM. In addition, c-Myc and IRF4 protein levels were reduced at 6 and 12 hours after treatment with YM155, respectively. As IRF4 and c-Myc form a positive feedback loop in myeloma cells, this observation indicates that c-Myc inhibition by YM155 treatment might lead to subsequent inhibition of IRF4 expression, and thus raises the possibility of YM155 target for c-Myc rather than IRF4. We next examined the mechanism of downregulation of c-Myc in RPMI8226 cells. Real-time quantitative RT-PCR assay showed that YM155 treatment reduced c-Myc mRNA level. On the other hand, proteasome inhibitor did not prevent the suppression of c-Myc expression by YM155 treatment. These Results suggest that YM155 transcriptionally at least in part represses c-Myc in RPMI8226 cells. In conclusion, YM155 suppresses cell proliferation and survival in MM cells in part via not only inhibiting anti-apoptotic proteins such as survivin, Mcl-1 and XIAP but also repressing c-Myc oncogene. Further study is needed to clarify the molecular mechanism of downregulation of c-Myc induced by YM155. Our Results may provide a platform for clinical trials of YM155 in MM. Disclosures: No relevant conflicts of interest to declare.

Download Full-text

Poly-L-arginine: Enhancing Cytotoxicity and Cellular Uptake of Doxorubicin and Necrotic Cell Death

Anti-Cancer Agents in Medicinal Chemistry ◽

10.2174/1871520618666180412114750 ◽

2019 ◽

Vol 18 (10) ◽

pp. 1448-1456 ◽

Cited By ~ 3

Author(s):

Bahareh Movafegh ◽

Razieh Jalal ◽

Zobeideh Mohammadi ◽

Seyyede A. Aldaghi

Keyword(s):

Cell Death ◽

Cellular Uptake ◽

Combined Treatment ◽

Annexin V ◽

Cell Penetrating Peptides ◽

Short Exposure ◽

Dependent Manner ◽

Du145 Cells ◽

Induced Apoptosis ◽

Resistance To Doxorubicin

Objective: Cell resistance to doxorubicin and its toxicity to healthy tissue reduce its efficiency. The use of cell-penetrating peptides as drug delivery system along with doxorubicin is a strategy to reduce its side effects. In this study, the influence of poly-L-arginine on doxorubicin cytotoxicity, its cellular uptake and doxorubicin-induced apoptosis on human prostate cancer DU145 cells are assessed. Methods: The cytotoxicity of doxorubicin and poly-L-arginine, alone and in combination, in DU145 cells was evaluated at different exposure times using MTT assay. The influence of poly-L-arginine on doxorubicin delivery into cells was evaluated by fluorescence microscopy and ultraviolet spectroscopy. DAPI and ethidium bromide- acridine orange stainings, flow cytometry using annexin V/propidium iodide, western blot analysis with anti-p21 antibody and caspase-3 activity were used to examine the influence of poly-L-arginine on doxorubicininduced cell death. Results: Poly-L-arginine had no cytotoxicity at low concentrations and short exposure times. Poly-L-arginine increased the cytotoxic effect of doxorubicin in DU145 cells in a time-dependent manner. But no significant reduction was found in HFF cell viability. Poly-L-arginine seems to facilitate doxorubicin uptake and increase its intracellular concentration. 24h combined treatment of cells with doxorubicin (0.5 µM) and poly-L-arginine (1 µg ml-1) caused a small increase in doxorubicin-induced apoptosis and significantly elevated necrosis in DU145 cells as compared to each agent alone. Conclusion: Our results indicate that poly-L-arginine at lowest and highest concentrations act as proliferationinducing and antiproliferative agents, respectively. Between these concentrations, poly-L-arginine increases the cellular uptake of doxorubicin and its cytotoxicity through induction of necrosis.

Download Full-text

Anti-tumor activity of a novel proteasome inhibitor D395 against multiple myeloma and its lower cardiotoxicity compared with carfilzomib

Cell Death and Disease ◽

10.1038/s41419-021-03701-z ◽

2021 ◽

Vol 12 (5) ◽

Author(s):

Xuxing Shen ◽

Chao Wu ◽

Meng Lei ◽

Qing Yan ◽

Haoyang Zhang ◽

...

Keyword(s):

Multiple Myeloma ◽

Proteasome Inhibitor ◽

Osteoclast Differentiation ◽

Dependent Manner ◽

Serum Enzyme ◽

Herg Channels ◽

Anti Tumor Activity ◽

Dose Dependent

AbstractCarfilzomib, a second-generation proteasome inhibitor, has significantly improved the survival rate of multiple myeloma (MM) patients, but its clinical application is still restricted by drug resistance and cardiotoxicity. Here, we identified a novel proteasome inhibitor, D395, and assessed its efficacy in treating MM as well as its cardiotoxicity at the preclinical level. The activities of purified and intracellular proteasomes were measured to determine the effect of D395 on the proteasome. CCK-8 and flow cytometry experiments were designed to evaluate the effects of D395 on cell growth and apoptosis. The effects of D395 and carfilzomib on serum enzyme activity, echocardiography features, cardiomyocyte morphology, and hERG channels were also compared. In our study, D395 was highly cytotoxic to MM cell lines and primary MM cells but not normal cells, and it was well tolerated in vivo. Similar to carfilzomib, D395 inhibited osteoclast differentiation in a dose-dependent manner. In particular, D395 exhibited lower cardiotoxicity than carfilzomib in all experiments. In conclusion, D395 is a novel irreversible proteasome inhibitor that has remarkable anti-MM activity and mild cardiotoxicity in vitro and in vivo.

Download Full-text

The Olive Leaves Extract Has Anti-Tumor Effects against Neuroblastoma through Inhibition of Cell Proliferation and Induction of Apoptosis

Nutrients ◽

10.3390/nu13072178 ◽

2021 ◽

Vol 13 (7) ◽

pp. 2178

Author(s):

Fabio Morandi ◽

Veronica Bensa ◽

Enzo Calarco ◽

Fabio Pastorino ◽

Patrizia Perri ◽

...

Keyword(s):

Cell Cycle ◽

Cell Proliferation ◽

Cell Viability ◽

Cell Cycle Progression ◽

Treatment Strategies ◽

Annexin V ◽

Dependent Manner ◽

Induction Of Apoptosis ◽

Dose Dependent

Neuroblastoma (NB) is the most common extra-cranial solid tumor of pediatric age. The prognosis for high-risk NB patients remains poor, and new treatment strategies are desirable. The olive leaf extract (OLE) is constituted by phenolic compounds, whose health beneficial effects were reported. Here, the anti-tumor effects of OLE were investigated in vitro on a panel of NB cell lines in terms of (i) reduction of cell viability; (ii) inhibition of cell proliferation through cell cycle arrest; (iii) induction of apoptosis; and (iv) inhibition of cell migration. Furthermore, cytotoxicity experiments, by combining OLE with the chemotherapeutic topotecan, were also performed. OLE reduced the cell viability of NB cells in a time- and dose-dependent manner in 2D and 3D models. NB cells exposed to OLE underwent inhibition of cell proliferation, which was characterized by an arrest of the cell cycle progression in G0/G1 phase and by the accumulation of cells in the sub-G0 phase, which is peculiar of apoptotic death. This was confirmed by a dose-dependent increase of Annexin V+ cells (peculiar of apoptosis) and upregulation of caspases 3 and 7 protein levels. Moreover, OLE inhibited the migration of NB cells. Finally, the anti-tumor efficacy of the chemotherapeutic topotecan, in terms of cell viability reduction, was greatly enhanced by its combination with OLE. In conclusion, OLE has anti-tumor activity against NB by inhibiting cell proliferation and migration and by inducing apoptosis.

Download Full-text

Anticancer effects of mifepristone on human uveal melanoma cells

Cancer Cell International ◽

10.1186/s12935-021-02306-y ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Prisca Bustamante Alvarez ◽

Alexander Laskaris ◽

Alicia A. Goyeneche ◽

Yunxi Chen ◽

Carlos M. Telleria ◽

...

Keyword(s):

Cell Death ◽

Cell Growth ◽

Progesterone Receptor ◽

Dna Fragmentation ◽

Cell Lines ◽

Caspase 3 ◽

Annexin V ◽

Dependent Manner ◽

Concentration Dependent Manner ◽

Free Dna

Abstract Background Uveal melanoma (UM), the most prevalent intraocular tumor in adults, is a highly metastatic and drug resistant lesion. Recent studies have demonstrated cytotoxic and anti-metastatic effects of the antiprogestin and antiglucocorticoid mifepristone (MF) in vitro and in clinical trials involving meningioma, colon, breast, and ovarian cancers. Drug repurposing is a cost-effective approach to bring approved drugs with good safety profiles to the clinic. This current study assessed the cytotoxic effects of MF in human UM cell lines of different genetic backgrounds. Methods The effects of incremental concentrations of MF (0, 5, 10, 20, or 40 μM) on a panel of human UM primary (MEL270, 92.1, MP41, and MP46) and metastatic (OMM2.5) cells were evaluated. Cells were incubated with MF for up to 72 h before subsequent assays were conducted. Cellular functionality and viability were assessed by Cell Counting Kit-8, trypan blue exclusion assay, and quantitative label-free IncuCyte live-cell analysis. Cell death was analyzed by binding of Annexin V-FITC and/or PI, caspase-3/7 activity, and DNA fragmentation. Additionally, the release of cell-free DNA was assessed by droplet digital PCR, while the expression of progesterone and glucocorticoid receptors was determined by quantitative real-time reverse transcriptase PCR. Results MF treatment reduced cellular proliferation and viability of all UM cell lines studied in a concentration-dependent manner. A reduction in cell growth was observed at lower concentrations of MF, with evidence of cell death at higher concentrations. A significant increase in Annexin V-FITC and PI double positive cells, caspase-3/7 activity, DNA fragmentation, and cell-free DNA release suggests potent cytotoxicity of MF. None of the tested human UM cells expressed the classical progesterone receptor in the absence or presence of MF treatment, suggesting a mechanism independent of the modulation of the cognate nuclear progesterone receptor. In turn, all cells expressed non-classical progesterone receptors and the glucocorticoid receptor. Conclusion This study demonstrates that MF impedes the proliferation of UM cells in a concentration-dependent manner. We report that MF treatment at lower concentrations results in cell growth arrest, while increasing the concentration leads to lethality. MF, which has a good safety profile, could be a reliable adjuvant of a repurposing therapy against UM.

Download Full-text

Activated CD4+CD25+ T cells selectively kill B lymphocytes

Blood ◽

10.1182/blood-2005-11-4502 ◽

2006 ◽

Vol 107 (10) ◽

pp. 3925-3932 ◽

Cited By ~ 305

Author(s):

Dong-Mei Zhao ◽

Angela M. Thornton ◽

Richard J. DiPaolo ◽

Ethan M. Shevach

Keyword(s):

Cell Proliferation ◽

T Cells ◽

Cell Death ◽

B Cells ◽

B Cell ◽

T Cell Activation ◽

Fas Ligand ◽

Cell Function ◽

Cell Contact ◽

Dependent Manner

The suppressive capacity of naturally occurring mouse CD4+CD25+ T cells on T-cell activation has been well documented. The present study is focused on the interaction of CD4+CD25+ T cells and B cells. By coculturing preactivated CD4+CD25+ T cells with B cells in the presence of polyclonal B-cell activators, we found that B-cell proliferation was significantly suppressed. The suppression of B-cell proliferation was due to increased cell death caused by the CD4+CD25+ T cells in a cell-contact–dependent manner. The induction of B-cell death is not mediated by Fas–Fas ligand pathway, but surprisingly, depends on the up-regulation of perforin and granzymes in the CD4+CD25+ T cells. Furthermore, activated CD4+CD25+ T cells preferentially killed antigen-presenting but not bystander B cells. Our results demonstrate that CD4+CD25+ T cells can act directly on B cells and suggest that the prevention of autoimmunity by CD4+CD25+ T cells can be explained, at least in part, by the direct regulation of B-cell function.

Download Full-text

Rosiglitazone Inhibits Adrenocortical Cancer Cell Proliferation by Interfering with the IGF-IR Intracellular Signaling

PPAR Research ◽

10.1155/2008/904041 ◽

2008 ◽

Vol 2008 ◽

pp. 1-11 ◽

Cited By ~ 24

Author(s):

Giulia Cantini ◽

Adriana Lombardi ◽

Elisabetta Piscitelli ◽

Giada Poli ◽

Elisabetta Ceni ◽

...

Keyword(s):

Cell Proliferation ◽

Signaling Pathways ◽

Intracellular Signaling ◽

Phosphatidyl Inositol ◽

Inhibitory Effect ◽

Peroxisome Proliferator ◽

Dependent Manner ◽

Adrenocortical Cancer ◽

Peroxisome Proliferator Activated Receptor ◽

Igf I

Rosiglitazone (RGZ), a thiazolidinedione ligand of the peroxisome proliferator-activated receptor (PPAR)-γ, has been recently described as possessing antitumoral properties. We investigated RGZ effect on cell proliferation in two cell line models (SW13 and H295R) of human adrenocortical carcinoma (ACC) and its interaction with the signaling pathways of the activated IGF-I receptor (IGF-IR). We demonstrate a high expression of IGF-IR in the two cell lines and in ACC. Cell proliferation is stimulated by IGF-I in a dose- and time-dependent manner and is inhibited by RGZ. The analysis of the main intracellular signaling pathways downstream of the activated IGF-IR, phosphatidyl inositol 3-kinase (PI3K)-Akt, and extracellular signal-regulated kinase (ERK1/2) cascades reveals that RGZ rapidly interferes with the Akt and ERK1/2 phosphorylation/activation which mediates IGF-I stimulated proliferation. In conclusion, our results suggest that RGZ exerts an inhibitory effect on human ACC cell proliferation by interfering with the PI3K/Akt and ERK1/2 signaling pathways downstream of the activated IGF-IR.

Download Full-text

Endothelial Cells Induce Multiple Myeloma Cell Proliferation Protect Against Conventional and Novel Therapies.

Blood ◽

10.1182/blood.v104.11.2354.2354 ◽

2004 ◽

Vol 104 (11) ◽

pp. 2354-2354

Author(s):

Shaji Kumar ◽

Noopur Raje ◽

Teru Hideshima ◽

Klaus Podar ◽

Kenji Ishitsuka ◽

...

Keyword(s):

Multiple Myeloma ◽

Cell Proliferation ◽

Endothelial Cells ◽

Tumor Cell ◽

Blood Vessels ◽

Intracellular Signaling ◽

De Novo ◽

Cell Contact ◽

Protective Effects ◽

Tumor Cell Proliferation

Abstract Angiogenesis or formation of new blood vessels from existing blood vessels, in contrast to vasculogenesis or de novo formation of new vessels, plays an important role in the progression and spread of most cancers. Multiple myeloma (MM) is characterized by increased microvessel density (MVD), a quantitative estimate of angiogenesis, which correlates with stage of disease. MVD increases with progression from MGUS to smoldering MM to newly diagnosed MM and relapsed MM. It is a powerful prognostic factor, predicting for overall survival. To further elucidate the biological basis for the prognostic value of increased angiogenesis in MM, we studied the interactions of MM cells with endothelial cells using HUVECS as a model system. Co-culture of MM cells (MM1.S, OPM2, U266) with HUVECS induced tumor cell proliferation. Enhanced tumor cell proliferation correlated with the number of HUVECs and was greater than that triggered by co-culture with patient bone marrow stromal cells. When HUVECs were fixed prior to co-culture there was a significant decrease in the tumor cell proliferation. Addition of HUVEC conditioned media to the MM cell lines also induced proliferation. Importantly, HUVECS protected against anti-MM agents including conventional agents (Dexamethasone, Doxorubicin, Melphalan) and novel drugs (Revlimid™). The protective effect afforded by co-culture was lost on HUVEC fixation. Intracellular signaling events following MM cell-endothelial cell contact were studied to understand the mechanisms of the proliferative and protective effects. Western blotting demonstrated activation of the JAK/STAT, PI3K/Akt and the MAPK pathways, mediating proliferation and survival. Ongoing studies focused on understanding cytokine as well as adhesion-mediated interactions between the endothelial cells and the MM cells will identify targets for new therapeutic approaches in MM.

Download Full-text