Vitamin K2 Modulates Differentiation and Apoptosis of Both Myeloid and Erythroid Lineages

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 3993-3993 ◽  
Author(s):  
Eriko Sada ◽  
Yasunobu Abe ◽  
Rie Ohba ◽  
Yoshimichi Tachikawa ◽  
Eriko Nagasawa ◽  
...  
Keyword(s):  
Cell Lines ◽  
Peripheral Blood ◽  
Conflicts Of Interest ◽  
Annexin V ◽  
Apoptotic Cells ◽  
Dependent Manner ◽  
Hematopoietic Progenitors ◽  
Erythroid Progenitors ◽  
Apoptotic Effect ◽  
Myeloid Progenitors

Abstract Abstract 3993 Myelodysplastic syndrome (MDS) is a stem cell disorder characterized by ineffective hematopoiesis eventually leading to maturation arrest and leukemic transformation. It is well-known that VK2 induces differentiation and apoptosis in acute myeloid leukemia (AML) cell lines such as HL-60 and U937. Based on the studies of AML cell lines, several clinical trials of VK2 therapy for MDS patients have been conducted, and they showed improvement of cytopenia and reductions in blastic cells. Interestingly, hematological improvement was also observed in MDS patients with low percentage of blasts, and a differentiation/apoptosis-inducing effect on blasts alone could not explain this fact. Thus, the effects of VK2 on primary hematopoietic progenitors were examined from the perspective of differentiation and apoptosis. Mobilized CD34-positive cells from peripheral blood were used for the examination of myeloid lineage cells, and were cultured in IMDM containing 20% FCS, 20 ng/mL rhSCF, 20 ng/mL rhIL-3, with or without VK2. VK2 induced significant increase of CD11b-positive cells on day 4 (35.8% ± 12.3% with 10 μM VK2 vs. 10.7% ± 1.9% without VK2, P=0.0034) and day 6 (42.7% ± 6.3% with 10 μM VK2 vs. 24.1% ± 8.6% without VK2, P=0.0235). CD14-positive cells also increased significantly on day 4 (8.0% ± 0.3% with 10 μM VK2 vs. 4.1% ± 1.5% without VK2, P=0.008). Furthermore, after treatment with VK2, mRNA expression levels of both C/EBPα and PU.1 were elevated in a dose-dependent manner, and a significant increase was shown at 10 μM of VK2 on day 6. These results indicate that VK2 promotes the differentiation of myeloid progenitors through the upregulation of transcriptional factors C/EBPα and PU.1. The effect of VK2 on the apoptosis of myeloid progenitors was also examined. VK2 increased the number of apoptotic cells determined by Annexin V assay transiently on day 4 (58.9% ± 6.3% with 10 μM VK2 vs. 36.1% ± 2.8% without VK2, P<0.0001), but no significant increase was found on day 6. Next, human erythroid colony forming cells (ECFCs) purified from peripheral blood were used for the examination of erythroid lineage cells. ECFCs were cultured in IMDM containing 15% FCS, 15% human AB serum, 2 U/ml rhEPO, 20 ng/mL rhSCF, 10 ng/mL rhIL-3 (depleted on day 3), with or without VK2 (added on day 3). In ECFCs, VK2 did not affect the expressions of transferrin receptor (TfR) and glycophorin A (GPA) or the expression level of β-globin mRNA. However, the expression of GATA-1 mRNA increased significantly on day 7 with 10 μM of VK2. VK2 seems to have the potential to promote the differentiation of ECFCs through the upregulation of transcriptional factor GATA-1, although this differentiating effect on ECFCs was much smaller than that on myeloid progenitors. Furthermore, VK2 exhibited an anti-apoptotic effect on day 7 ECFCs under erythropoietin (EPO) -depletion. The percentage of apoptotic cells after 24 hours of EPO-depletion, which was determined by Annexin V-positivity, was significantly reduced with VK2 at low concentrations (0.5-2 μM) (76.9% ± 4.7% with 1 μM VK2 vs. 88.3% ± 1.7% without VK2, P=0.0019). VK2 lost its anti-apoptotic effect at concentrations greater than 5 μM. This anti-apoptotic effect was not shown in erythroleukemic cell line AS-E2. Finally, the expression of steroid and xenobiotic receptor (SXR), which was recently identified as a receptor of VK2, on primary hematopoietic cells was examined. SXR was expressed on myeloid progenitors, but not on erythroid progenitors. SXR agonist rifampicin also upregulated the expressions of CD11b and CD14 on myeloid progenitors. The differentiation-promoting effect of VK2 on myeloid progenitors seems to be mediated partly through SXR signaling. These results indicate that the effect of VK2 varies by cell type. The major effect on myeloid progenitors was promoting differentiation, whereas its anti-apoptotic effect seemed to be dominant in erythroid progenitors. Although the detailed mechanism of VK2's effect on differentiation or apoptosis of hematopoietic progenitors remains unknown, the effect of VK2 therapy in MDS patients could be partly explained by these mechanisms. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Coagulation Factor XII Plays an Important Role in Procoagulant Activity of Apoptotic Cells

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 2457-2457
Author(s):  
Aizhen Yang ◽  
Yi Wu
Keyword(s):  
Knockout Mice ◽  
Conflicts Of Interest ◽  
Coagulation Factor ◽  
Annexin V ◽  
Procoagulant Activity ◽  
Contact System ◽  
Coagulation System ◽  
Factor Xii ◽  
Apoptotic Cells ◽  
Dependent Manner

Abstract Apoptosis can be induced in a variety of pathological disorders, including inflammation, autoimmune diseases, and chemotherapy. When cells undergo apoptosis, they express phosphatidylserine (PS) on cell membrane surface and thus become procoagulant. Although it has been known that the procoagulant activity of apoptotic cells are tightly associated with thrombotic disorders, such as atherothrombosis and Trousseau syndrome, the mechanisms by which apoptotic cells activate the coagulation system and enhance blood clotting are largely unknown. In this study we investigated which coagulation factor(s) is involved in this process. Using western blotting and chromogenic substrate assay, we found that incubation with apoptotic cells induced by Dexamethasone (DXMS), but not with viable cells, resulted in rapid cleavage and activation of FXII. Moreover, apoptotic cells-mediated FXII activation was significantly increased in the presence of prekallikrein (PK) and high molecular weight kininogen (HK), other two components of plasma contact system. However, incubation of apoptotic cells did not cause dramatic changes of other coagulation factors, suggesting a selective association of FXII activation with apoptotic cells. Activation of FXII by apoptotic cells was markedly inhibited by a specific anti-kallikrein antibody, indicating the activation of the contact system by apoprotic cells. Flow cytometric measurement showed that FXII bound to apoptotic cells in a concentration-dependent manner, which was inhibited by annexin V and PS liposome. A surface plasmon resonance assay showed a direct binding of FXII to PS (KD=3.9E-9 M). When challenged by apoptotic cells, clotting time of plasma from FXII-knockout mice was significantly prolonged, which was reversed by replenishment with human FXII. Moreover, an inhibitory anti-FXII antibody completely prevented apoptotic cells-induced intrinsic tenase complex formation. Consistently, apoptotic cells significantly increased thrombin production in normal plasma, which were attenuated by PS blocker annexin V, an inhibitory anti-FXII antibody, and the deficiency of FXII, respectively. Addition of human FXII to XII-deficient plasma recovered thrombin generation. As evaluated by ELISA, the levels of thrombin-antithrombin complex in circulation were significantly increased when apoptotic cells were intravenously injected into wild-type mice, but not in FXII-knockout mice. In conclusion, FXII plays an important role in apoptotic cells-mediated procoagulant activity. Disclosures No relevant conflicts of interest to declare.

WP1066: A Novel PI-3K Inhibitor with Antileukemic Activity in Philadelphia Chromosome-Positive ALL.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 850-850
Author(s):  
Alessandra Ferrajoli ◽  
Stefan Faderl ◽  
Tony Wang ◽  
Waldemar Priebe ◽  
Hagop Kantarjian ◽  
...  
Keyword(s):  
Cell Lines ◽  
Tyrosine Kinases ◽  
Philadelphia Chromosome ◽  
Annexin V ◽  
Adenosine Diphosphate ◽  
Time Dependent ◽  
Apoptotic Cells ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Dose Dependent

Abstract Prognosis for patients with Philadelphia chromosome (Ph) positive ALL remains dismal. Ph+ ALL is characterized by the activation of several tyrosine kinases that provide the neoplastic clone with its proliferative capacity and survival advantage. We found that WP1066, a novel derivative of the tyrphostin AG490, inhibits the JAK-STAT pathway and cytokine-dependent and independent signaling pathways. Therefore, we sought to investigate the activity of WP1066 in Ph+ ALL. To do this, we first studied the effect of WP1066 on the Ph+ ALL cell lines Z-119 and Z-181 (Estrov Z et al. J. Cell Physiol.166(3):18, 1996). Using the MTT assay we found that WP1066 inhibited the growth of both Z-119 and Z-181 cells in a concentration-dependent manner with only 8% and 4% of the cells surviving at a concentration of 4 mM, respectively. Similarly, the clonogenic growth of both Z-119 and Z-181 cells was effectively inhibited by WP1066 with more than 90% reduction in colony numbers at concentration of 4 mM. Using Western Immunoblott analysis of cell lysates, we found that 4 mM of WP1066 induced caspase-3 cleavage in a time- and dose-dependent manner in both Z-119 and Z-181 cells. In addition, WP-1066 downregulated uncleaved poly (adenosine diphosphate-ribose) polymerase (PARP) and upregulated cleaved PARP protein levels in a time-dependent manner after 2 hours of exposure to 4 mM. We further evaluated induction of apoptosis using the annexin V-FITC assay and showed a dose dependent increase of the fraction of apoptotic cells in both Z-119 and Z-181 cells. After 24 hour of exposure to 4 mM of WP1066 the fraction of apoptotic cells increased by 23% and 43%, respectively. To elucidate the mechanisms by which WP1066 induces growth inhibition and apoptosis in Ph+ ALL cells, we investigated the effect of this agent on the phosphatidylinositol 3-kinase (PI-3K) pathway because the PI-3K pathway is constitutively activated in Ph+ leukemias. We found that WP1066 inhibited the phosphorylation of AKT in a time-dependent fashion in both cell lines and that this inhibitory effect lasted for 24 hours. In conclusion, our data suggest that exposure to WP1066 induces caspase-dependent apoptosis, is associated with PI3-K inhibition and reduces the growth of the Ph+ cell lines Z-119 and Z-181. The activity of WP1066 in Ph+ ALL should be further studied.

scholarly journals The pro-apoptotic effect of a Terpene-rich Annona cherimola leaf extract on leukemic cell lines

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Carl Ammoury ◽  
Maria Younes ◽  
Marianne El Khoury ◽  
Mohammad H. Hodroj ◽  
Tony Haykal ◽  
...  
Keyword(s):  
Cell Death ◽  
Cell Lines ◽  
Leaf Extract ◽  
Annexin V ◽  
Parp Cleavage ◽  
Dependent Manner ◽  
Western Blots ◽  
Annona Cherimola ◽  
Apoptotic Effect ◽  
Ethanolic Leaf Extract

Abstract Background The edible fruit Annona cherimola has previously shown many nutritional and medicinal properties. The current study evaluates the anti-cancer and anti-proliferative properties of Annona cherimola ethanolic leaf extract (AELE) on Acute Myeloid Leukemia (AML) cell lines cultured in vitro (Monomac-1 and KG-1). Methods The anti-proliferative effect of A. cherimola ethanolic leaf extract was evaluated via cell viability assay. Its pro-apoptotic effect was assessed through Cell Death ELISA and dual Annexin V/PI staining. To further investigate the molecular mechanism by which the extract promoted apoptosis and inhibited the proliferation of the AML cells used, apoptotic protein expression was determined through western blots. Extract composition was elucidated by Gas Chromatography-Mass Spectrometry (GC-MS). Results Our results showed that the treatment with A. cherimola ethanolic leaf extract exhibited an inhibitory effect on the proliferation of both cancer cell lines used in a dose- and time-dependent manner, with no toxic effects on normal mononuclear cells (MNCs) isolated from human bone marrow. This effect was mediated by DNA fragmentation and apoptosis, as revealed by Cell Death ELISA and dual Annexin V/PI staining. Western blot analysis revealed a Bax/Bcl2 dependent mechanism of apoptosis, as well as PARP cleavage, confirming the apoptotic results observed previously. These effects may be attributed to the presence of terpenes which constitute a large component of the leafy extract, as revealed via GC-MS. Conclusion All the data presented in our study show that the terpene-rich A. cherimola ethanolic leaf extract exhibits an anti-proliferative and pro-apoptotic effect on the AML cell lines used.

scholarly journals Anticancer effects of mifepristone on human uveal melanoma cells

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.

scholarly journals Dynamics of GATA transcription factor expression during erythroid differentiation

Blood ◽  
1993 ◽  
Vol 82 (4) ◽  
pp. 1071-1079 ◽  
Author(s):  
M Leonard ◽  
M Brice ◽  
JD Engel ◽  
T Papayannopoulou
Keyword(s):  
Transcription Factor ◽  
Cell Lines ◽  
Peripheral Blood ◽  
Erythroid Differentiation ◽  
Regulatory Control ◽  
Leukemic Cells ◽  
Erythroid Cells ◽  
Gata Factor ◽  
Erythroid Progenitors ◽  
Factor Expression

Abstract Although the formation of terminally differentiated erythroid cells has been shown to require the presence of a functional GATA-1 gene in vivo, the role of this transcription factor and other members of the GATA family at earlier stages of erythroid differentiation is unclear. In this report, the expression of GATA-1, GATA-2, and GATA-3 has been examined in enriched peripheral blood progenitors before and after culture in a well-characterized liquid culture system. In addition primary leukemic cells as well as several erythroleukemic and nonerythroid cell lines were analyzed for GATA factor expression. The results show that the profile of GATA factor expression in erythroid cells is distinct from that of myeloid or lymphoid lineages. Erythroleukemic cell lines express little or no GATA-3, but high levels of GATA-1 and GATA-2. When they are induced to display the terminal erythroid phenotype, little change in the level of GATA-1 is detected but a significant decline in the levels of GATA-2 is observed commensurate with the degree of maturation achieved by the cells. Enrichment of erythroid progenitors from peripheral blood leads to selection of cells that express both GATA-1 and GATA-2. As the enriched populations are cultured in suspension in the presence of multiple cytokines, the levels of both GATA-1 and GATA-2 initially increase. However, in cultures containing only erythropoietin, which show exclusive erythroid differentiation, the levels of GATA-1 continue to increase, whereas GATA-2 expression declines as erythroid maturation progresses. In contrast, cultures lacking Epo (ie, with interleukin-3 and kit ligand) display limited progression towards both the myeloid and erythroid pathways, and high levels of expression of both GATA-1 and GATA-2 are maintained. Despite the initial upregulation of GATA-1 expression in the latter cultures, terminal erythroid differentiation does not occur in the absence of erythropoietin. These results indicate that GATA-1 upregulation is associated with both the initiation and the maintenance of the erythroid program, but that these two processes appear to be under separate regulatory control. Thus, the dynamic changes in the levels of different GATA factors that occur during primary erythroid differentiation suggest that the levels of these factors may influence the progression to specific hematopoietic pathways.

scholarly journals Dihydrochalcone Derivative Induces Breast Cancer Cell Apoptosis via Intrinsic, Extrinsic, and ER Stress Pathways but Abolishes EGFR/MAPK Pathway

2019 ◽  
Vol 2019 ◽  
pp. 1-18 ◽  
Author(s):  
Wasitta Rachakhom ◽  
Patompong Khaw-on ◽  
Wilart Pompimon ◽  
Ratana Banjerdpongchai
Keyword(s):  
Breast Cancer ◽  
Er Stress ◽  
Cell Lines ◽  
Cell Apoptosis ◽  
Mapk Pathway ◽  
Annexin V ◽  
Mapk Signaling ◽  
Dependent Manner ◽  
Induced Apoptosis ◽  
Mcf 7

Dihydrochalcone derivatives are active compounds that have been purified from the Thai medicinal plant Cyathostemma argenteum. The objectives of this study were to investigate the effects of two dihydrochalcone derivatives on human breast cancer MDA-MB-231 and MCF-7 cell proliferation and to study the relevant mechanisms involved. The two dihydrochalcone derivatives are 4′,6′-dihydroxy-2′,4-dimethoxy-5′-(2″-hydroxybenzyl)dihydrochalcone (compound 1) and calomelanone (2′,6′-dihydroxy-4,4′-dimethoxydihydrochalcone, compound 2), both of which induced cytotoxicity toward both cell lines in a dose-dependent manner by using MTT assay. Treatment with both derivatives induced apoptosis as determined by annexin V-FITC/propidium iodide employing flow cytometry. The reduction of mitochondrial transmembrane potential (staining with 3,3′-dihexyloxacarbocyanine iodide, DiOC6, employing a flow cytometer) was established in the compound 1-treated cells. Compound 1 induced caspase-3, caspase-8, and caspase-9 activities in both cell lines, as has been determined by specific colorimetric substrates and a spectrophotometric microplate reader which indicated the involvement of both the extrinsic and intrinsic pathways. Calcium ion levels in mitochondrial and cytosolic compartments increased in compound 1-treated cells as detected by Rhod-2AM and Fluo-3AM intensity, respectively, indicating the involvement of the endoplasmic reticulum (ER) stress pathway. Compound 1 induced cell cycle arrest via enhanced atm and atr expressions and by upregulating proapoptotic proteins, namely, Bim, Bad, and tBid. Moreover, compound 1 significantly inhibited the EGFR/MAPK signaling pathway. In conclusion, compound 1 induced MDA-MB-231 and MCF-7 cell apoptosis via intrinsic, extrinsic, and ER stress pathways, whereas it ameliorated the EGFR/MAPK pathway in the MCF-7 cell line. Consequently, it is believed that compound 1 could be effectively developed for cancer treatments.

scholarly journals Anticancer Potential of Fruit Extracts from Vatica diospyroides Symington Type SS and Their Effect on Program Cell Death of Cervical Cancer Cell Lines

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Atchara Chothiphirat ◽  
Kesara Nittayaboon ◽  
Kanyanatt Kanokwiroon ◽  
Theera Srisawat ◽  
Raphatphorn Navakanitworakul
Keyword(s):  
Cervical Cancer ◽  
Cancer Cells ◽  
Cell Lines ◽  
Morphological Changes ◽  
Annexin V ◽  
Siha Cell ◽  
Caspase 8 ◽  
Dependent Manner ◽  
Cervical Cancer Cells ◽  
Dose Dependent

Vatica diospyroides Symington is locally known as Chan-Ka-Pho in Thailand. Ancient people have used it as therapeutic plant for cardiac and blood tonic cure. The purpose of this study was to investigate the potential cytotoxicity and selectivity of the extracts from V. diospyroides type SS fruit on cervical cancer HeLa and SiHa cell lines and to examine its underlying mechanism of action. MTT assay revealed that the extracts showed inhibition of cell survival in a dose-dependent manner and exhibited highly cytotoxic activity against both HeLa and SiHa cells with IC50 value less than 20 μg/mL along with less toxicity against L929 cells. Acetone cotyledon extract (ACE) showed the best selectivity index value of 4.47 (HeLa) and 3.51 (SiHa). Distinctive morphological changes were observed in ACE-treated cervical cancer cells contributing to apoptosis action. Flow cytometry analysis with Annexin V-FITC and PI staining precisely indicated that ACE induced apoptosis in HeLa and SiHa cell lines in a dose-dependent manner. Treatment of ACE with half IC50 caused DNA fragmentation and also activated increasing of bax and cleaved caspase-8 protein in HeLa cells after 48 h exposure. The results suggest that ACE has potent and selective cytotoxic effect against cervical cancer cells and the potential to induce bax and caspase-8-dependent apoptosis. Hence, the ACE could be further exploited as a potential lead in cancer treatment.

Endothelial Cell-Derived Microparticles in the Pathogenesis of Chemotherapy-Associated Hypercoagulability.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1457-1457
Author(s):  
Daniel Lechner ◽  
Marietta Kollars ◽  
Sabine Eichinger ◽  
Paul Alexander Kyrle ◽  
Ansgar Weltermann
Keyword(s):  
Thrombin Generation ◽  
Culture Media ◽  
Annexin V ◽  
Membrane Vesicles ◽  
Procoagulant Activity ◽  
Dependent Manner ◽  
Thrombin Generation Assay ◽  
Apoptotic Effect ◽  
Mitochondrial Dehydrogenase Activity

Abstract Background: Cisplatin-based chemotherapy is a risk factor of venous thromboembolism in cancer patients. The underlying pathogenesis remains unclear. We hypothesized an apoptotic effect of cisplatin on endothelial cells (EC) inducing a release of small membrane vesicles, so-called microparticles (MP) which are known to cause hemostasis activation. Objectives: To quantify the release of MP from EC following administration of cisplatin and to investigate MP-associated procoagulant mechanisms. Methods: Two EC lines (HUVEC, HMVEC-L) were exposed to cisplatin (1, 2.5, 5, 10, and 20 μM) for up to 120 h. Cell viability was assessed by quantification of mitochondrial dehydrogenase activity, counts and procoagulant activity of MP were measured by flow cytometry and a thrombin generation assay, respectively. Tissue factor (TF) antigen levels were determined by ELISA. Results: EC viability decreased in a dose- and time-dependent manner and was accompanied by an increasing release of MP into culture media (maximum: HUVEC + 544%; HMVEC-L + 1738%). In parallel, procoagulant activity of media increased by up to 150% (HUVEC) and 493% (HMVEC-L), respectively. The procoagulant activity was almost abolished by annexin V but was not suppressed by a monoclonal TF-antibody. TF antigen levels on MP were persistently low even at high cisplatin concentrations. Conclusion: At pharmacologically relevant concentrations, cisplatin induced a marked release of procoagulant MP from EC. Negatively charged phospholipids but not TF on MP were decisive for total thrombin generation. Further studies are warranted to investigate the cisplatin-induced release of EC-derived MP in vivo.

Targeting xIAP Is More Important Than Bcl-Xl in Lymphomas with Constitutive Activation of NF-kB.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 2390-2390
Author(s):  
Yanjuan He ◽  
Joan Cain ◽  
Lee Ratner ◽  
Leon Bernal-Mizrachi
Keyword(s):  
Cell Lines ◽  
Annexin V ◽  
Fold Increase ◽  
Daudi Cell ◽  
Xiap Expression ◽  
Apoptotic Effect ◽  
Effective Doses ◽  
Induction Of Apoptosis ◽  
Apoptotic Pathways

Abstract Pathways resulting in resistance to apoptosis are essential to the process of lymphomagenesis. One such pathway, the nuclear factor-kB (NFkB), has been shown to be a key element in coordinating the anti-apoptotic effect of these malignancies. However the mechanisms used by which NFkB prevents apoptosis are not well understood. It has been suggested that NFkB inhibits activation of the intrinsic, extrinsic and common apoptotic pathways. Previous work in our lab using two different virally mediated lymphoma models (Tax/HTLV1 and LMP1/EBV driven tumors) has identified two candidates that could explain these results: X chromosome-linked inhibitor of apoptosis (xIAP) and BCL-xL. Although the current literature extensively demonstrates the role of BCL-xL in lymphomas, little is known about the importance of xIAP in these malignancies. To answer this question we tested the apoptotic effect of etoposide or tumor necrosis factor (TNF) after knocking down bcl-xL and xIAP expression in our lymphoma models (SC and Daudi cell lines) using a lentivirus expressing siRNAs. After 24 hours of treatment with etoposide and TNF, we measured apoptosis by flow cytometry using double staining with Annexin V-Alexa Fluorescense and propidium iodide. Interestingly, xIAP siRNA-expressing cell lines demonstrated 2–4 fold increase in the induction of apoptosis after treatment with etoposide as compared to a nearly 2 fold increase in those expressing Bcl-xL siRNA (see Table below). No synergism was seen after treatment with TNF. Based on this finding, we then tested a novel small molecule, homolog smac, (SHC, kindly provided by Dr. PG Harren) to determine the possible therapeutic effect of xIAP inhibitors. After titration, the two most effective doses were selected (25 μM and 50 μM) to treat Daudi cell lines for 24hrs, with either etoposide or TNF. At doses of 25 μM , we observed a 2 fold increase in the induction of apoptosis produced by etoposide compared to that seen in control (DMSO + etoposide) or SHC alone and no synergism with TNF confirming the siRNA data. More importantly, at doses of 50 μM, SHC alone demonstrated activity with a 5 fold increase in apoptosis and a nearly 10 fold increase as compared to control (DMSO) when etoposide was added. Overall, we have demonstrated that xIAP and bcl-xL are important in mediating NFkB-resistance to apoptosis. However, our findings suggested that xIAP is a more potent anti-apoptotic signal and opens the door for further drug development aimed at testing xIAP-inhibitors in lymphomas. Induction of Apoptosis in xIAP or Bcl-xL siRNA expressing cell lines siRNA/Compound Etoposide TNF Untreated xIAP 43.1 ± 17.6 17.04 ± 1.4 14.3 ± 2 SC Bcl-xL 18.39± 3.7 9.4 ± 0.22 12.5 ± 2.7 Luc/DMSO 14.9 ± 1.8 14.4 ± 5.6 14.03 ± 1.25 xIAP 9.2 ± 3.2 4.7 ± 0.48 4.6 ± 0.44 Bcl-xL 8.9 ± 0.5 5.3 ± 1.7 4.16 ± 0.4 Daudi Luc/DMSO 5.49 ± 1.71 4.28 ± 0.5 6.2 ± 0.9 SHC 25 μM 20.07 ± 4.8 12.8 ± 3.9 12.1 ± 3.2 SHC 50 μM 47.7 ± 14.55 38.3 ± 0.99 32.7 ± 8.99

Fenretinide (4HPR) Inhibits Growth of Myeloma Cells in Their Microenvironment and Is a Potent Inhibitor of Angiogenesis and Osteoclastogenesis.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 3480-3480
Author(s):  
Xin Li ◽  
Wen Ling ◽  
Rinku Saha ◽  
Paul Perkins ◽  
Angela Pennisi ◽  
...  
Keyword(s):  
Tumor Cell ◽  
Cell Lines ◽  
Mtt Assay ◽  
Cell Apoptosis ◽  
Mononuclear Cells ◽  
Annexin V ◽  
Dependent Manner ◽  
Angiogenic Potential ◽  
Inhibition Of Angiogenesis ◽  
Induced Apoptosis

Abstract Fenretinide (4HPR) is a relatively safe neoclassical retinoid analog that inhibits growth of various tumors through increased intracellular ceramide and ROS, induction of tumor cell apoptosis and inhibition of angiogenesis. 4HPR has been successfully tested as a chemopreventive and chemotherapeutic agent in clinical trials on various malignancies. In contrast to retinoic acid, 4HPR induces cell apoptosis rather than differentiation and shows synergistic responses with chemotherapeutic drugs in different tumor cell types. The biological effect and therapeutic value in multiple myeloma (MM) has not been investigated. The aim of this study was to investigate the anti-MM effect and mechanism of action of 4HPR using 3 stroma-dependent and 2 stroma-independent MM cell lines established in our laboratory, CD138-selected primary MM cells and co-culture systems of these cells with human osteoclasts and mesenchymal stem cells (MSCs) as previously described (Yaccoby et al., Cancer Res 2004). MM cell apoptosis detected by annexin V flow cytometry and TUNNEL, tumor growth by MTT assay, changes in caspase 3, 8 and 9 activity using Western blotting and ROS production by 2′,7′-dichlorodihydrofluorescein diacetate (H2DCFDA) dye assay. 4HPR inhibits growth of all tested MM cells in a dose- and time-dependent manner. The IC50 after 48 hrs in serum-containing media was 10 μM using MTT assay. 4HPR (3 μM) increased percent of apoptotic MM cells by 2.5±0.4 folds (p<0.01). Co-culture of these cell lines with osteoclasts only partially protected MM cells from the proapoptotic effect of this drug. Furthermore, 4HPR also induced apoptosis of primary CD138-selected MM cells co-cultured with osteoclasts or MSCs, and inhibited growth of bortezomib-resistant MM cell lines. In contrast, 4HPR had only minimal cytotoxic effect on blood mononuclear cells and MSCs. The proapoptotic effect of 4HPR involved increased level of ROS by 2.55±0.67 folds in MM cells (p<0.01). We also detected reduced levels of procaspase and increased cleaved caspase 8, 9 and 3 within 24 hrs of incubation with this drug. Sphingosine-1 phosphate (S1P) partially protected MM cells from 4HPR-induced apoptosis suggesting that, as reported for other tumors, anti-MM mechanism of this drug involved increased intracellular ceramide. 4HPR significantly inhibited tube formation by HUVEC in a matrigel assay (p<0.0001), confirming its anti-angiogenic potential. This drug also effectively prevented formation of multinucleated osteoclasts in culture of human osteoclast precursors with RANKL and M-CSF (p<0.0001). Furthermore, mature osteoclasts viability as assessed by MTT assays was reduced following incubation with 3 μM 4HPR (p<0.0001). We conclude that 4HPR is a potent anti-MM agent, affecting growth of MM cells in their microenvironment directly through induction of apoptosis in mechanisms involving ROS, caspase and possibly ceramide, and indirectly through inhibition of angiogenesis and osteoclastogenesis. Our data also suggests that S1P, which is highly produced by activated platelets, is an important survival factor for MM cells. Study is underway to test anti-MM efficacy of 4HPR in the SCID-hu model for primary myeloma.

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