scholarly journals Herbal Extracts from Lycii Radicis Corex and Achyranthes japonica Prevent Multiple Myeloma

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 4918-4918
Author(s):  
Carol A. Morris ◽  
Syed Mehdi ◽  
Jenat Rahman ◽  
Pamela Rosales ◽  
Sun-Ok Lee ◽  
...  

Abstract Introduction Multiple Myeloma (MM) is a plasma cell malignancy that, despite advances in treatment, remains incurable. In over 90% of MM patients, aberrant bone remodeling occurs and results in osteolytic lesions. It severely reduces the patient's quality of life and increases mortality. Korean traditional medicine has a long-standing interest in healthy foods to enhance the immune system, energy-boost, and Yin-and-Yang balance. A healthy diet in Tradition medicine is based on accumulated observations from countless cases over multi-centuries. Traditional medicine has used herbal extracts (HE) from natural plants with fewer side effects and long-term treatment tolerance. In earlier studies, lycii radices cortex (LRC) and achyranthes japonica (AJ) containing herbal extracts (HE) have demonstrated the ability to enhance cell growth and mineralization of osteoblast cells while also inhibiting osteoclast differentiation. Furthermore, a sesquiterpene glucoside, (1'R,3'S,5'R,8'S,2 Z,4 E)-dihydrophaseic acid 3'-O-β-d-glucopyranoside (DPA3G) were isolated from the LRC ethanol extract and shown to be a bioactive compound for enhancement of cell growth and bone anabolic activity (Park et al). The current study investigated the effects of LRC+AJ containing HE on murine 5TGM1 MM-bearing mice. Methods We transplanted 1x10 6 cells of the enforced luciferase-expressing 5TGM1 (5TGM1-Luc) into 8~12-week-old Nod-Scid-IL2Rg null (NSG) mice via tail vein (representing an equal number of each sex). For LRC+AJ containing HE treatment, mice were divided into three groups; i) PBS group; ii) treatment group at 300 mg/kg, gavage, TIW started two weeks before MM transplant (TbT); and iii) treatment group at 300 mg/kg, gavage, TIW two weeks after MM transplant (TaT). We assessed tumor burden by weekly bioluminescence imaging (IVIS 200 Imager, Perkin Elmer). The spine was extracted from carcass and scanned at postmortem by Dual Energy X-ray Absorptiometry using PIXImus Densitometer (G.E. Lunar, Madison, USA) and micro-computed tomography (microCT; Scanco Medical AG, Switzerland). HE effects in cell growth were tested in the myeloma cells (5TGM1 and U266) and preosteoblast cells (MC3T3-E1). The cells were grown in various concentrations (8, 80, 800 ug/ml) of HE up to 96 hours. In addition, Chromatogram and Mass Spectrometry were conducted to identify the DPA3G. Results As shown in Figure 1A, this HE significantly increased the mouse survivals of both TbT and TaT groups with median survivals of undetermined and 52.5 days, respectively, while MM control had a median survival of 42 days. The Mantel-Cox test found that TbT and TaT mice were significantly different from the control group (P=0.0014 and 0.0182, respectively). Furthermore, DEXA scans at postmortem showed a significant increase in bone mineral density (BMD) and bone mineral content (BMC) in TbT and TaT groups than control MM mice. For a histomorphometry analysis, the spines were scanned by micro-CT and revealed that TbT and TaT groups had significantly increased bone volume over total volume (BV/TV) than control. To see if HE affects cell growth of myeloma cells and osteoblast cells, we further investigated the HE on preosteoblast cell line MC3T3-E1, mouse MM cell line 5TGM1-Luc, and human MM cell line U-266. Cells were treated with HE in various concentrations, and viability was assessed at 48 and 96 hours post-treatment. Remarkably, LRC+AJ containing HE increased MC3T3-E1 cell growth while it decreased 5TGM1 and U-266 cell viability. We identified the DAP3G and many other compounds in HE used in this study. Conclusions Our results demonstrated that LRC+AJ HE prevents MM and promotes bone formation in 5TGM1 engrafted NSG mice. We also found that LRC+AJ HE suppresses myeloma cell growth and enhances osteoblast cell survival. Although it is yet to be defined, a correlation of osteoblast activity and myeloma cell inhibition suggests a potential mechanism of the HE action to prevent MM progression. 1. Park E, Kim J, Yeo S, Lim E, Choi CW, Choi S, Li WY, Lee JW, Park JH, Huh D, Jeong SY. Anti-Osteoporotic Effects of Combined Extract of Lycii Radicis Cortexand Achyranthes japonica in Osteoblast and Osteoclast Cells and Ovariectomized Mice. Nutrients. 2019 Nov 9;11(11):2716. doi: 10.3390/nu11112716. PMID: 31717518; PMCID: PMC6893723.' Figure 1 Figure 1. Disclosures Huh: Dongwoodang Pharmacy Company: Current Employment. OffLabel Disclosure: Herbal Extracts from Lycii Radicis Corex and Achyranthes Japonica

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2346-2346
Author(s):  
Bonnie K. Arendt ◽  
Raphael Fonseca ◽  
Gregory Ahmann ◽  
Diane F. Jelinek

Abstract Multiple myeloma (MM) is a fatal disease characterized by the accumulation of malignant plasma cells in the bone marrow. Although progress has been made in better understanding growth control of this disease, effective treatment of MM patients with this disease is likely complicated by the extensive patient to patient variability that exists, as well variability within the tumor population itself. Thus, there is abundant evidence that intraclonal or intratumor heterogeneity exists in myeloma as revealed by morphologic and phenotypic heterogeneity in primary myeloma cells isolated from a single patient. We have had a long-standing interest in the growth regulation of myeloma cells and have hypothesized, along with other investigators, that there may only be a subset of myeloma cells that exhibits extensive proliferative potential. Understanding how cellular compartments within the malignant clone, as defined by identical immunoglobulin variable region sequence, may vary in growth regulation properties in isolation or in the company of less proliferative tumor cell subsets is key to understanding disease progression and how to better target the putative proliferative subset in myeloma. In this study, we have used a methylcellulose clonogenic assay to study intraclonal heterogeneity in a panel of human MM cell lines. Each of these cell lines, DP-6, KAS-6/1, KP-6, and, exhibit a variable response to IL-6 and IGF-I, and our goal was to evaluate growth responsiveness of individual subclones from each of these cell lines. Myeloma cell lines were plated at a concentration of 200-1000 cells in 1 ml Methocult H4533 in 35 mm gridded dishes with or without various cytokines. Following 3 weeks of culture, colonies were scored and those consisting of >40 cells were isolated, expanded, and studied further. Of interest, subclones isolated from each of the cell lines displayed significant differences in growth response to various cytokines in addition to specific morphologic and phenotypic differences. In this regard, results emerging from the DP-6 cell line were particularly intriguing. We have previously shown that the DP-6 cell line displays a proliferative response to both IL-6 and IGF-I and expresses autocrine IL-6 at a low level. Analysis of the growth properties of individual DP-6 clones revealed the existence of DP-6 cells (clone 1-15) that proliferate at a rapid rate in the apparent absence of exogenous growth factors. Whereas a neutralizing antibody to IL-6 did not inhibit cell growth, addition of a blocking antibody to the IGF-IR, (αIR3), completely blocked growth factor independent proliferation. Phenotypic analysis also displayed variation between the parental cell line and its subclone. For instance, the parental DP-6 cells largely expressed CD45 at a high level, whereas the clone 1-15 did not. Finally, we have also further characterized MM cell line subclones by gene profiling and FISH (fluorescence in situ hybridization) analysis to link specific phenotype and genotypes with patterns of cell growth. These results provide additional evidence that intratumor heterogeneity exists in myeloma. These studies further demonstrate how growth regulation may vary considerably among cellular subsets of the malignant population. Understanding what factors regulate the balance of specific myeloma cell subpopulations is key to an understanding of tumor progression. In summary, these studies provide a necessary foundation for future studies of the growth potential of subsets found in primary MGUS, SMM and MM patient samples.


Blood ◽  
2004 ◽  
Vol 103 (5) ◽  
pp. 1829-1837 ◽  
Author(s):  
Karène Mahtouk ◽  
Michel Jourdan ◽  
John De Vos ◽  
Catherine Hertogh ◽  
Geneviève Fiol ◽  
...  

Abstract We previously found that some myeloma cell lines express the heparin-binding epidermal growth factor–like growth factor (HB-EGF) gene. As the proteoglycan syndecan-1 is an HB-EGF coreceptor as well as a hallmark of plasma cell differentiation and a marker of myeloma cells, we studied the role of HB-EGF on myeloma cell growth. The HB-EGF gene was expressed by bone marrow mononuclear cells in 8 of 8 patients with myeloma, particularly by monocytes and stromal cells, but not by purified primary myeloma cells. Six of 9 myeloma cell lines and 9 of 9 purified primary myeloma cells expressed ErbB1 or ErbB4 genes coding for HB-EGF receptor. In the presence of a low interleukin-6 (IL-6) concentration, HB-EGF stimulated the proliferation of the 6 ErbB1+ or ErbB4+ cell lines, through the phosphatidylinositol 3-kinase/AKT (PI-3K/AKT) pathway. A pan-ErbB inhibitor blocked the myeloma cell growth factor activity and the signaling induced by HB-EGF. This inhibitor induced apoptosis of patients'myeloma cells cultured with their tumor environment. It also increased patients' myeloma cell apoptosis induced by an anti–IL-6 antibody or dexamethasone. The ErbB inhibitor had no effect on the interaction between multiple myeloma cells and stromal cells. It was not toxic for nonmyeloma cells present in patients' bone marrow cultures or for the growth of hematopoietic progenitors. Altogether, these data identify ErbB receptors as putative therapeutic targets in multiple myeloma.


Blood ◽  
1989 ◽  
Vol 74 (1) ◽  
pp. 11-13 ◽  
Author(s):  
XG Zhang ◽  
B Klein ◽  
R Bataille

Abstract It has recently been demonstrated that interleukin-6 (IL-6) is a potent myeloma-cell growth factor in the majority of patients with multiple myeloma (MM). Using an anti-bromodeoxyuridine monoclonal antibody (MoAb) to specifically count myeloma cells in the S-phase (ie, labeling index, LI), we demonstrate that the IL-6 responsiveness of myeloma cells in vitro is directly correlated with their LI in vivo. Myeloma cells from all 13 patients with high LIs in vivo (greater than or equal to 1%) responded in vitro to IL-6, the strongest response occurring in cells from five patients with plasma-cell leukemia. In contrast, the cells of only two of eight patients with low myeloma-cell LIs in vivo (less than 1%) responded to IL-6 in vitro. After seven days of culturing with 1,000 U/mL recombinant IL-6 (rIL-6), the median LI value in the first group of patients (in vivo LI greater than or equal to 1%) was 11%, ie 11 times higher (P less than .01) than the median LI value (1%) in the second group of patients (in vivo LI less than 1%). Thus, the in vitro IL-6 responsiveness of myeloma cells is directly related to their in vivo proliferative status, and hence to the severity of the disease.


Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 4868-4868
Author(s):  
Juan Li ◽  
Junhe Li ◽  
Shaokai Luo ◽  
Yin Zhao

Abstract Objective To study the different expression of death receptors and decoy receptors on mononuclear cells from patients with multiple myeloma and myeloma cell line KM3 and compare the different expression of TRAIL receptors after chemotherapy or exposure to doxorubicin, to explore the mechanisms by which TRAIL selectively kills tumor cells. Methods Semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) and flow cytometry was used to investigate the expression of four receptors on mononuclear cells in 23 multiple myeloma patients and myeloma cell line KM3 and 15 controls, we furthermore compared the changes of expression mode after chemotherapy and incubation of KM3 cell with sub-clinical concentration of Doxorubicin. Results There finds only DR4 and DR5 on KM3 cell line without the expression of DcR1 and DcR2. Expression of DR4 and DR5 on mononuclear cells of MM patients is higher than that of controls (P<0.05), but DcR1 and DcR2 expression was lower than that of controls (P<0.05), after chemotherapy and exposure to Doxorubicin, the expression of DR5 on MM cells was up-regulated (P<0.05) Conclusions The expression of four receptors on myeloma cells and normal controls was significantly different, which might account for the selective killing effect of TRAIL on MM cells. DR5 was up-regulated on KM3 when incubating with Doxorubicin and after chemotherapy which suggests chemotherapy agents might enhance the apopotosis of MM cells through up-regulating of DR5 receptor.


Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 3444-3444
Author(s):  
Magne Rekvig ◽  
Anne-Tove Brenne ◽  
Torstein Baade Ro ◽  
Anders Waage ◽  
Magne Borset ◽  
...  

Abstract Multiple myeloma has two distinct features: Expansion of malignant plasma cells within the bone marrow accompanied by skeletal destruction. Bone morphogenetic proteins (BMPs) have been shown to induce apoptosis and inhibit growth in myeloma cells. BMPs are members of the TGF-β superfamily of proteins capable of inducing bone formation, and regulate proliferation, differentiation and apoptosis. We have investigated myeloma cell apoptosis and proliferation with BMP-4 and −6 in concert with the myeloma cell growth factors interleukin (IL)-2, IL-6, IL-10, IL-15, IL-21, tumor necrosis factor (TNF)-α and insulin-like growth factor (IGF)-1. Eight samples of highly purified myeloma cells from patients and a human myeloma cell line, IH-1 (Brenne AT et al. Blood. 2002 May 15;99(10):3756–62.), were used in this study. Cytokine concentrations used in the referred experiments were for BMP-4 20ng/ml, BMP-6 250ng/ml, IL-15 20ng/ml and IL-6 0,1ng/ml, respectively. Growth inhibition was measured in a proliferation assay by methyl-[3H]-thymidine incorporation and apoptosis by annexin V- FITC-binding/PI-uptake on flow cytometry. IL-15 antagonized growth inhibition (Figure A) and prevented apoptosis induced by BMP-4 (Figure B) and BMP-6 in the myeloma cell line IH-1. IL-15 also antagonized the growth inhibition induced by BMP-4 and/or BMP-6 in three out of eight patient samples. Neither IL-6, nor any of the other investigated cytokines were able to rescue the myeloma cells from growth inhibition and apoptosis induced by BMP-4 and -6. Among the investigated cytokines, we found that IL-15 has a unique capability to antagonize BMP- induced apoptosis and growth inhibition in myeloma cells. We examined cleavage of the proapoptotic protein caspase-3 and found that BMP-4 activated caspase-3 in the IH-1 cell line. This activation of caspase-3 was blocked by IL-15 but not by IL-6. We have demonstrated a possible mechanism for myeloma cells to escape apoptosis and growth-inhibition within the bone marrow. Intramedullar levels of IL-15 and BMPs may play a role in the pathogenesis of multiple myeloma. Figure A. Proliferation in response to BMP-4 stimulus Figure A. Proliferation in response to BMP-4 stimulus Figure B. Apoptosis in response to BMP-4 stimulus Figure B. Apoptosis in response to BMP-4 stimulus


Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 3417-3417
Author(s):  
Yutaka Okuno ◽  
Hiro Tatetsu ◽  
Shikiko Ueno ◽  
Hiroyuki Hata ◽  
Yasuhiro Yamada ◽  
...  

Abstract It has been reported that disruption of transcription factors critical for hematopoiesis, such as C/EBPa and AML1, is involved in leukemogenesis. PU.1 is a transcription factor important for both myeloid and lymphoid development. We reported that mice in which the levels of PU.1 were 20% of that of wild-type developed acute myeloid leukemia, T cell lymphoma, and a CLL-like disease. These findings strongly suggest that PU.1 has tumor suppressive activity in multiple hematopoietic lineages. Last year, we reported that PU.1 is downregulated in a majority of multiple myeloma cell lines and and freshly isolated CD138 positive myeloma cells from certain number of myeloma patients, and that tet-off inducible exogenous expression of PU.1 in PU.1 negative myeloma cell lines induced cell growth arrest and apoptosis. Based on their PU.1 expression levels, we divided the myeloma patients into two groups, namely PU.1 high and PU.1 low-to-negative, (cutoff index of 25th percentile of the PU.1 expression level distribution among all patients). The PU.1 low-to-negative patients had a significantly poorer prognosis than the PU.1 high patients. To elucidate the mechanisms of downregulation of PU.1, we performed sequence and epigenetic analysis of the promoter region and the -17 kb upstream region that is conserved among mammalians and important for proper expression of PU.1. There are no mutations in these regions of all five myeloma cell lines. In contrast, the -17 kb upstream region was highly methylated in 3 of 4 PU.1 negative myeloma cell lines, while the promoter region was also methylated to various levels in all five myeloma cell lines including one PU.1 positive cell line. These data suggested that the downregulation of PU.1 in myeloma cell lines might be dependent on the methylation of both regulatory regions of PU.1 gene, especially the -17 kb upstream region. We also evaluated the mechanisms of cell growth arrest and apoptosis of myeloma cell lines induced by PU.1. Among apoptosis-related genes, we identified that TRAIL was upregulated after PU.1 induction. To evaluate the effect of upregulation of TRAIL, we stably introduced siRNA for TRAIL into myeloma cell lines expressing PU.1, and we found that apoptosis of these cells was partially suppressed by siRNA for TRAIL, suggesting that apoptosis of myeloma cells induced by PU.1 might be at least partially due to TRAIL upregulation. We are currently performing DNA microarray analysis to compare the expression levels of genes between before and after PU.1 induction, in order to further elucidate the mechanisms of cell growth arrest and apoptosis.


Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 4481-4481 ◽  
Author(s):  
Estefania Garcia-Guerrero ◽  
Tea Gogishvili ◽  
Sophia Danhof ◽  
Martin Schreder ◽  
Celine Pallaud ◽  
...  

Abstract Background: Immunotherapy with monoclonal antibodies (mAbs) has recently entered the clinical arena in multiple myeloma, including Daratumumab that targets CD38 on malignant plasma cells. The efficacy of mAbs depends on antigen density and expression of accessory ligands on target cells to initiate cell- and complement-dependent effector mechanisms. Here, we investigate the use of the histone deacetylase inhibitor (HDACi) Panobinostat to modulate target antigen expression and ligand profile on myeloma in favor of potent mAb-mediated recognition and destruction. We show that Panobinostat augments CD38 expression specifically on myeloma cells and demonstrate powerful synergy with anti-CD38 mAb Daratumumab in pre-clinical models. Methods: The myeloma cell line MM1.S and primary myeloma cells were treated with titrated doses of Panobinostat (0, 10, 25 nM) and expression of CD38 and a panel of additional target molecules including B-cell maturation antigen (BCMA) and SLAMF7, as well as accessory ligands analyzed by flow cytometry at 24, 48 and 72 hours. Antibody-dependent cellular cytotoxicity (ADCC) against Panobinostat treated and untreated myeloma cells was analyzed at 4 and 20 hours after addition of PBMC at an effector to target ratio of 25:1 in the presence of Daratumumab (1, 10, 50 ug/mL) or an isotype control antibody. Results: We first treated the myeloma cell line MM1.S with Panobinostat and analyzed its direct cytotoxic anti-myeloma effect. Consistent with previous work, the percentage of live MM1.S myeloma cells had decreased to 85% and 50% after 48 hours of exposure to 10 and 25 nM respectively. We analyzed expression of CD38 on residual live, i.e. 7-AAD negative MM1.S cells by flow cytometry and observed a 1.5 (10 nM) and 2-fold (25 nM) increase of CD38 expression by mean fluorescence intensity (MFI) compared to baseline levels and untreated control cells. The increase in CD38 expression was already detectable after 24 hours and plateaued between 48 and 72 hours. We confirmed our observation in primary myeloma cells from multiple donors (n=4) and detected an even stronger increase to 2 (10 nM) and 4-fold (25 nM) higher CD38 expression compared to untreated cells at 48 hours. Interestingly, expression of BCMA and SLAMF7 was not increased after Panobinostat treatment at all tested concentrations and time points in both MM1.S and primary myeloma. We confirmed that Panobinostat-induced upregulation of CD38 specifically occurred in myeloma, and neither observed this phenomenon in a panel of leukemia and lymphoma cell lines including Raji (Burkitt) and JeKo-1 (mantle cell), nor on resting/activated primary CD8+ and CD4+ T cells that we isolated from peripheral blood of several donors (n=3). Next, we were interested in determining whether the increase in CD38 expression enabled superior anti-myeloma activity of the anti-CD38 mAb Daratumumab. Panobinostat pre-treatment was done for 48 hours at 10 nM as this is a clinically achievable serum level with currently approved regimens. Indeed, significantly higher ADCC was mediated by Daratumumab at all tested concentrations (1, 10 and 50 ug/mL) against MM1.S that we had exposed to Panobinostat. At 4 hours, ADCC was 45% and 25% in Panobinostat-treated and untreated MM1.S respectively, and at 20 hours, near-complete, >90% ADCC of Panobinostat-pre-treated MM1.S had occurred, whereas only 65% of MM1.S were eliminated by Daratumumab without Panobinostat pre-treatment. These data were confirmed in multiple experiments with MM1.S and PBMC from different donors, and with primary myeloma cells. Experiments to evaluate synergy of Panobinostat and Daratumumab therapy in a xenograft model (NSG/MM1.S) are ongoing. Conclusions: Our data demonstrate that the HDACi Panobinostat induces upregulation of CD38 on myeloma and a subsequent dramatic increase of Daratumumab-mediated ADCC in pre-clinical models. These data suggest that Panobinostat could be used synergistically with Daratumumab in a clinical setting to increase response rates and extend duration of responses to Daratumumab. Panobinostat has a known ability to modulate the transcriptional profile of myeloma cells and our data demonstrate for the first time that this ability can be utilized to augment the therapeutic index of antibody-based immunotherapy in multiple myeloma. Disclosures Pallaud: Novartis: Employment. Lehmann:Novartis: Employment. Hudecek:Novartis: Research Funding.


2017 ◽  
Vol 35 (15_suppl) ◽  
pp. 8039-8039 ◽  
Author(s):  
Konstantinos Lontos ◽  
Juraj Adamik ◽  
Peng Zhang ◽  
Quanhong Sun ◽  
David Roodman ◽  
...  

8039 Background: Myeloma bone disease is characterized by osteoclast activation and long-term osteoblast suppression. We investigated if Semaphorin 4D (Sema4D; CD100) plays a role in these processes. Sema4D has been shown to be a potent osteoblast inhibitor (Negishi-Koga T et al, Nat Med. 2011). A study recently identified that the breast cancer cell line MDA-MB-231 utilizes Sema4D to create osteolysis (Yang Y et al, PLOS One 2016). There have been previous data that Sema4D is increased in the serum of myeloma patients (Terpos et al, Blood 2012) and that co-culturing myeloma cell lines with osteocytes increases the expression of Sema4D mRNA in both (Suvannasankha et al, Blood 2016). We sought to investigate if myeloma cells are using Sema4D to suppress bone formation and if they affect the levels of Sema4D produced by osteoclasts. Methods: We used lentivirus carrying shRNA for Sema4D or control (Scr) to knock down the level of the protein in the 5TGM1 murine myeloma cell line. Knockdown was verified by qPCR and Western Blot. We subsequently co-cultured the 5TGM1 cells with the MC3T3-subclone M4 (MC4) murine stromal cell line for 2 days, removed the myeloma cells and then differentiated the MC4 cells using ascorbic acid and β-glycerolphosphate. At day 5, we analyzed the cells for Runx2 (a critical gene for the differentiation of stromal cells into osteoblasts) expression utilizing qPCR. Also, we performed qPCR in primary osteoclast (OCL) mouse cells differentiating into OCL with RANKL with or without pre-treatment with myeloma-conditioned media for 3 days before the addition of RANKL. Results: When 5TGM1-Scr were co-cultured with MC4 cells the expression of Runx2 on day 5 was decreased (p=0.02). Strikingly, the 5TGM1-shSema4D cells when co-cultured with MC4s did not have the same effect and allowed the upregulation of Runx2 expression on day 5 (p=0.01). Myeloma-conditioned media increased Sema4D expression by OCL throughout the 5 days of differentiation 2 to 3-fold (p=0.01 for day 5). Conclusions: The myeloma cells seem to be utilizing Sema4D both directly and indirectly to inhibit bone formation. Targeted therapy against Sema4D may improve outcomes and fracture-free survival for multiple myeloma patients.


2013 ◽  
Vol 31 (15_suppl) ◽  
pp. e19534-e19534
Author(s):  
Yubin Kang ◽  
Jagadish Kummetha Venketa

e19534 Background: Multiple myeloma (MM) is the second most common hematological malignancy in the United States and accounts for ~10,600 deaths annually. MM remains an incurable disease and almost all patients will eventually relapse and become refractory to currently available therapeutic agents. There is an unmet need for better understanding the disease’s molecular pathways and for identifying novel therapeutic targets. Sphingolipid metabolism is being increasingly recognized as a key pathway in tumor cell proliferation and in tumor sensitivity to anticancer drugs. We hypothesize that altered sphingolipid metabolism plays an important role in the pathogenesis of MM, thus providing a novel target in the treatment of MM. Methods: We first assayed sphingolipid metabolism including sphingolipid metabolites and sphingolipid metabolizing genes in myeloma cell lines, in freshly isolated human primary CD138+myeloma cells, and in publically available dataset. We then tested the efficacy of the selective SK2 inhibitor (ABC294640) and the SK2 shRNA in killing myeloma cells in vitro. Results: 1) Compared to immortalized B cells, the levels of pro-apoptotic ceramides were decreased whereas the proliferative sphingosine 1-phosphate (S1P) was increased in myeloma cell lines. 2) The expression of several key sphingolipid-metabolizing genes including sphingosine kinase (SK) 1 and 2 was altered in freshly isolated human primary bone marrow myeloma cells and in publically available microarray dataset. 3) The selective SK2 inhibitor (ABC294640) induces apoptotic cell death and inhibits myeloma cell growth with an IC50of ~20 μM in 9 myeloma cell lines. 4) Interestingly, OPM-1 myeloma cell line was extremely sensitive to ABC294640 with an IC50of <5 µM whereas U266 myeloma cell line was resistant to ABC294640. SK2 shRNA induced apoptotic cell death in OPM-1, but not in U266 cells. We are currently investigating the molecular mechanisms underlying the resistance of U266 myeloma cells to ABC294640. Conclusions: Our data demonstrated that sphingolipid metabolism provides an attractive target in the treatment of refractory/relapased multiple myeloma.


Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 4916-4916
Author(s):  
Serhan Alkan ◽  
Jan Duus ◽  
Ismail H. Bahar ◽  
Keith F. Izban ◽  
Hytham Al-Masri ◽  
...  

Abstract Heat Shock Protein 90 (HSP90) is required for structural folding and maintenance of conformational integrity of various proteins, including several associated with cellular signaling. Recent studies utilizing 17-allylamino-17-demethoxygeldanamycin (17-AAG), an inhibitor of HSP90, demonstrated antitumor effect in solid tumors. In order to test whether HSP90 could be targeted in multiple myeloma (MM) patients, we first investigated expression of HSP90 by immunofluorescence and flow cytometric analysis in a myeloma cell line (U266) and primary myeloma cells. Following demonstration of HSP90 expression in myeloma cells, archival samples of 32 MM patients were analyzed by immunoperoxidase staining. Myeloma cells in all patients showed strong cytoplasmic expression of HSP90 in all samples and 55 % also demonstrated concurrent nuclear immunopositivity. Treatment of U266 and primary MM cells with 17AAG resulted in significantly increased apoptosis compared to untreated control cells. Analysis of anti-apoptotic BCL2 family proteins in MM cells incubated with 17-AAG revealed down-regulation of BCL-2, BCL-XL and MCL-1. Furthermore, while low concentration of bortezomib had no cell death, combination of 17AAG and bortezomib treatment revealed a synergistic apoptotic effect on the U266 cell line. These data suggest that targeted inhibition of HSP90 may prove to be a valid and innovative strategy for the development of future therapeutic options for MM patients.


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