Targeting ß-Catenin Signaling in DLBCL with ICG-001 and PAM-1 Suppresses Cell Proliferation and Induces Apoptosis

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 5382-5382
Author(s):  
Angela A. Fachel ◽  
Ashlesha Shrikant Muley ◽  
Cem Meydan ◽  
Xabier Agirre ◽  
Leandro Cerchietti ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Cell Lines ◽  
Transcriptional Activity ◽  
Annexin V ◽  
Transcript Abundance ◽  
Current Treatment ◽  
Creb Binding Protein ◽  
Treatment Regimens ◽  
P21 Activated Kinase ◽  
Induced Apoptosis

Abstract Introduction: DLBCL is a fast-growing, aggressive form of NHL and ~30% of the patients are not cured with the current treatment regimens. Recently Wnt/ ß-catenin signaling has been identified as a new target pathway for lymphoma. To specifically target B-catenin we picked two drugs that act downstream of the Wnt/B-catenin pathway. ICG-001 inhibits TCF/β-catenin mediated transcription by competing specifically with β-catenin for CREB binding protein (CBP), but not for p300. PAM-1 is a p21-activated kinase 4 (PAK4) allosteric modulator acting as a nucleo-cytoplasmic shuttling protein. PAK4 interacts with and phosphorylates β-catenin on Ser675, promoting TCF/B-catenin transcriptional activity and stabilizing β-catenin through inhibition of its degradation. We conducted a pre-clinical study with ICG-001 and PAM-1 ß-catenin inhibitors on 16 ABC and GCB DLBCL cell lines and provided a molecular rationale for Wnt/ß-catenin directed therapy. Material & Methods: RNAseq data from DLBCL cell lines, patient and normal B-cell samples were used to profile transcript abundance of the Wnt pathway in DLBCL. Western blotting was used to measure ß-catenin expression in 16 ABC and GCB DLBCL cell lines. Pharmacological inhibition of ß-catenin-signaling was tested using ICG-001 and PAM-1 compounds. A metabolically active cellular assay (CellTiter Glo) and flow cytometry with annexin V staining were used to determine cell viability and apoptosis. To address the specificity of the drug response, DLBCL cells were transduced with a ß-catenin/TCF pathway reporter, knocked down for ß-catenin, and canonical Wnt target expression was assessed using quantitative real-time (qRT-PCR) and Western blot. Results: ß-catenin is expressed on all DLBCL cell lines at different levels that do not correlate with the ABC/GCB classification. The ß-catenin inhibitors ICG-001 and PAM-1 significantly reduced viability in all ABC and GCB DLBCL cell lines, regardless of DLBCL subtype. The EC50 after 48h of treatment ranged from 1.4 μM to 6.3 μM for ICG001 and from 80 nM to 870 nM for PAM-1. Both compounds suppressed cell proliferation, induced apoptosis, and reduced Wnt/ß-catenin transcriptional activity. Conclusions: Our data indicate that targeting ß-catenin pathway with ICG-001 and PAM-1 could be therapeutically beneficial to DLBCL patients. Disclosures Melnick: Janssen: Research Funding.

The Diterpenoid Lactone Andrographolide (ANDRO) Stimulates Autophagy and Induces Reactive Oxygen Species (ROS)-Dependent Apoptosis in Lymphoma Cell Lines

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 4991-4991
Author(s):  
Shuo Yang ◽  
Andrew M. Evens ◽  
Sheila Prachand ◽  
Leo I. Gordon
Keyword(s):  
Cell Proliferation ◽  
Cell Death ◽  
Cell Lines ◽  
Redox State ◽  
Annexin V ◽  
Lymphoma Cell ◽  
Time Dependent ◽  
Cellular Redox ◽  
Forkhead Transcription Factors ◽  
Induced Apoptosis

Abstract ANDRO is a diterpenoid lactone isolated from Andrographis paniculata (King of Bitters), an important herbal medicine used in China. It has been reported to have anti-inflammatory, anti-hypertensive, anti-viral and immunostimulant properties. It has also been shown to inhibit cancer cell proliferation and induce apoptosis in HL-60 (leukemia), PC-3 (prostatic adenocarcinoma), MDA-MB-231 (breast cancer), HepG2 (liver cancer), HeLa (cervical cancer) and HCT116 (colorectal cancer) cell lines. The diterpenoids have been found to generate ROS and may increase apoptosis by altering the cellular redox state. We hypothesized that ANDRO would lead to cell death in lymphoma cell lines and that the effect may be related to altered cellular redox state. We studied the Burkitt p53 mutated Ramos cell line, the mantle cell lymphoma line Granta and L428, a resistant EBV-negative Hodgkin lymphoma cell line. We found that after incubation with increasing concentrations of ANDRO, there was dose and time-dependent cell death as measured by MTT. The IC50 (concentration that achieved 50% cell proliferation inhibition) at 48h was 20μM for Ramos, 40μM for Granta, and 50μM for L428. ROS was measured by oxidation of 2’7’dichlorofluorescein diacetate (DCFDA) to dichlorofluorescein (DCF) and analyzed by fluorescence-activated cell sorting (FACS) following incubation at 1hour (h), 2h, 3h, 5h, 38h, and 48h with ANDRO (20–80μM). ANDRO increased ROS production in all lymphoma cell lines, which was abrogated by the antioxidant N-acetyl-L-cysteine (NAC). Maximum ROS generation with ANDRO was seen at 48h for Ramos (1.7 fold), 5h for Granta (1.6 fold), and 38h for L428 (2.4 fold). To determine the mechanism of cell death, we measured apoptosis by Annexin-V/propidium iodide (PI), and detected by flow cytometry (FACS). Cells were treated with ANDRO in the presence or absence of the reduced glutathione (GSH) depleting agent buthionine sulfoximine (BSO) (100μM) for 28h, 48h, and 72h. We found that the AC50 (concentration that achieved 50% apoptosis) was 40μM for Ramos at 72h, 40μM for Granta at 48h and >80μM for L428 at 48h, while in the presence of BSO it was <10μM for Ramos at 72h, between 30–40μM for Granta at 28h and between 30–40μM for L428 at 48h. Apoptosis was completely blocked, by NAC, both in the presence and absence of BSO. Further, ANDRO induced PARP cleavage and activation of caspases 3, 8, and 9 in Granta and Ramos. Next, we explored the relationship of ANDRO and Forkhead transcription factors. ANDRO caused dephosphorylation of FOXO3a or FOXO1, in a dose- and time-dependent manner, and this was reversible by NAC. Downstream proteins of FOXO3a, Bim, p27kip1 and the isoforms of the autophagy-related protein LC3B were upregulated, and this was reversed by NAC. The LC3B isoform-II, which is cleaved from LC3B-I, is a marker of autophagy activation. To determine the role of autophagy in cell death related to ANDRO, we inhibited autophagy with 3-methyladenine (1–2mM) and found significant enhancement of ANDRO-induced apoptosis in Granta and Ramos. Finally, ANDRO induced apoptosis (>60% Annexin-V+/PI+) in malignant B-cells from a patient with chronic lymphocytic leukemia/small lymphocytic lymphoma (trisomy 12, peripheral blood absolute lymphocyte count 95.2 K/uL, bulky adenopathy) very low concentrations (5μM at 18h) in vitro, which was also reversible with NAC. We conclude that ANDRO induces ROS-dependent apoptosis in lymphoma cell lines and in a primary tumor sample, which is enhanced by depletion of GSH and inhibited by the antioxidant NAC. These effects appear to proceed through caspase activation and inhibition of autophagy, and are in part dependent on signaling through forkhead transcription factors and altered cellular redox pathways. Further studies of diterpenoids as single agents or in combination with other anti-lymphoma agents are warranted.

scholarly journals Vulpinic Acid as a Natural Compound Inhibits the Proliferation of Metastatic Prostate Cancer Cell by Inducing Apoptosis

2021 ◽  
Author(s):  
Demet Cansaran Duman ◽  
Gamze Guney Eskiler ◽  
Betül Çolak ◽  
Elif Sozen Kucukkara
Keyword(s):  
Prostate Cancer ◽  
Metastatic Prostate Cancer ◽  
Molecular Mechanisms ◽  
Treatment Options ◽  
Annexin V ◽  
Current Treatment ◽  
Pcr Analysis ◽  
G1 Arrest ◽  
Advanced Analysis ◽  
Induced Apoptosis

Abstract Lichen secondary metabolites have drawn considerable attention in recent years due to limitations of current treatment options. Vulpinic acid (VA) obtained from Letharia vulpina lichen species exerts a remarkable cytotoxic effect on different cancer types. However, the therapeutic efficacy of VA in metastatic prostate cancer (mPC) cells has not been investigated. In the present study, we aimed to identify VA-mediated cytotoxicity in PC-3 mPC cells compared with control cells. After identification of the cytotoxic concentrations of VA, VA induced apoptosis was analyzed by Annexin V, cell cycle, acridine orange and propidium iodide staining and RT-PCR analysis. Our findings showed that VA significantly decreased the viability of PC-3 cells (p < 0.01) and caused a considerable early apoptotic effect through G0/G1 arrest, nuclear bleebing and the activation of particularly initiator caspases. Therefore, VA may be a potential treatment option for mPC patients. However, the underlying molecular mechanisms of VA-induced apoptosis with advanced analysis should be further performed.

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 Deguelin Induces Apoptosis by Targeting Both EGFR-Akt and IGF1R-Akt Pathways in Head and Neck Squamous Cell Cancer Cell Lines

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Yuh Baba ◽  
Masato Fujii ◽  
Toyonobu Maeda ◽  
Atsuko Suzuki ◽  
Satoshi Yuzawa ◽  
...  
Keyword(s):  
Growth Factor ◽  
Head And Neck ◽  
Cell Lines ◽  
Squamous Cell ◽  
Cell Cancer ◽  
Growth Factor Receptor ◽  
Annexin V ◽  
Akt Activation ◽  
Igf1r Signaling ◽  
Induced Apoptosis

Deguelin, a rotenoid compound from the African plantMundulea sericea(Leguminosae), has been shown to possess antitumor activities but the exact role for the growth factor receptor mediated signaling pathway in head and neck squamous cell carcinoma (HNSCC) is currently still unclear. In the present study, we investigated the effect of deguelin on epidermal growth factor receptor (EGFR) and insulin-like growth factor-1 receptor (IGF1R) pathways in HNSCC cell lines. Flowcytometric analysis revealed accumulation of annexin V positivity in deguelin-treated cells, showing that deguelin induced apoptosis. The deguelin-induced apoptosis was accompanied by the reduction of constitutive phosphorylated levels of IGF1R, Akt, and extracellular signal-regulated kinase1/2 (ERK1/2). LY294002-mediated inhibition of phosphatidylinositol-3 kinase, which is an upstream effector for Akt activation, increased cleavage of poly(ADP-ribosyl) polymerase (PARP) but ERK inhibition by U0126 did not. Deguelin inhibited both IGF-1- and EGF-induced Akt activation. These results showed that deguelin possessed antitumor effect by targeting Akt in dual axis such as EGFR and IGF1R signaling pathways and suggested that it provides an applicable therapeutic strategy for HNSCC patients.

VEGF Upregulates Mcl-1 Expression and Protects Multiple Myeloma Cells Against Starvation Induced-Apoptosis.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 631-631
Author(s):  
Steven Le Gouill ◽  
Klaus Podar ◽  
Martine Amiot ◽  
Teru Hideshima ◽  
Dharminder Chauhan ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Cell Proliferation ◽  
Cell Lines ◽  
Cell Cycle Progression ◽  
Myeloid Cell ◽  
Fibroblast Cell ◽  
Transfected Cells ◽  
Murine Embryonic Fibroblast ◽  
Induced Apoptosis

Abstract Vascular endothelial growth factor (VEGF) induces proliferation of MM cells and induces interleukin-6 (IL-6) secretion in a paracrine loop involving MM cells and bone marrow stromal cells. In turn, IL-6 triggers multiple myeloma (MM) cell proliferation and also protects against apoptosis by upregulating Myeloid-cell-leukemia 1 (Mcl-1), a critical survival protein in MM cells. The goal of our study was to investigate the role of Mcl-1 in VEGF induced-proliferation and protection against apoptosis. Using two murine embryonic fibroblast cell lines as a model (a Mcl-1 deleted cell line and its wild type: Mcl-1Δ/null and Mcl-1wt/wt MEFs, respectively), we here demonstrate that deletion of Mcl-1 reduces fetal bovine serum (FBS), VEGF, and IL-6 induced-proliferation. In addition, we demonstrate that the percentage of cells in S phase is lower in Mcl-1Δ/null compared to Mcl-1wt/wt MEFs (21% (+/−1) versus 30% (+/− 3), respectively). Taken together, these results demonstrate that Mcl-1 is required to mediate VEGF, Il-6 and FBS-induced-proliferation and cell cycle progression. To highlight the key anti-apoptotic role of Mcl-1 in MM cells, humans MM1s cells were transfected with Mcl-1 siRNA. Specific inhibition of Mcl-1 was associated with decreased proliferation (42% and 61% decreases at 24 and 48 h, respectively) and induction of apoptosis (subG1 peak: 22% and 41% in Mcl-1 siRNA transfected cells versus 15% and 15 % in non-transfected cells at 24 and 48 h, respectively), confirming that Mcl-1 is critical for both proliferation and protection against apoptosis in MM cells. In 3 human MM cell lines (MM1s, U266 and MM1R) and MM patient cells we next showed that Mcl-1 protein expression, but not other bcl-2 family members, is upregulated by VEGF in a time and dose manner; and conversely that the pan-VEGF inhibitor GW654652, blocks VEGF induced-upregulation of Mcl-1. Furthermore using flow cytometry with a double staining (CD38-FITC and Apo 2.7-PE), we demonstrate that VEGF protects MM patient cells from FBS-starvation-induced-apoptosis: the percentage of apoptotic MM patient cells (CD38++ and Apo 2.7+) in non starved medium (RPMI 1640 supplemented with 10% FBS) was 15% versus 93% in starved medium (RPMI 1640 supplemented with FBS 2%), and 48% in starved medium supplemented with 25ng/ml VEGF. In conclusion, our study demonstrates that VEGF protects MM cells against apoptosis, and that VEGF-induced MM cell proliferation and survival is mediated via Mcl-1. these studies provide the preclinical framework for novel therapeutics targeting both Mcl-1 and/or VEGF to improve patient outcome in MM.

Myc Targets Cks1 To Provoke Proliferation and Lymphomagenesis.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 2618-2618
Author(s):  
Ulrich Keller ◽  
Jennifer B. Old ◽  
Jonas Nilsson ◽  
Lisa Nilsson ◽  
Kirsteen Maclean ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
B Cells ◽  
Burkitt Lymphoma ◽  
Poor Prognosis ◽  
Transcriptional Activity ◽  
Kinase Inhibitor ◽  
Ex Vivo ◽  
Cyclin Dependent Kinase ◽  
Cyclin Dependent Kinase Inhibitor ◽  
Induced Apoptosis

Abstract Reduced levels of the cyclin dependent kinase inhibitor p27Kip1 connote poor prognosis in cancer. In human Burkitt lymphoma, and in pre-cancerous B cells and lymphomas arising in Eμ-Myc transgenic mice, p27Kip1 expression is markedly reduced. Furthermore, the Cks1 component of the SCFSkp2 complex that is necessary for p27Kip1 ubiquitylation and degradation, and to a lesser extent Skp2, are induced by Myc ex vivo and in Eμ-Myc B-cells and lymphomas, and up-regulation of CKS1 and SKP2 are hallmarks of Burkitt lymphoma. While loss of Skp2 has rather modest effects, the deletion of Cks1 in Eμ-Myc B-cells elevates p27Kip1 levels, reduces proliferation and delays lymphoma development. In contrast, Myc-induced apoptosis and transcriptional activity are not affected by Cks1 (or Skp2) loss. Therefore, Myc accelerates cell proliferation and promotes tumorigenesis through its ability to selectively induce Cks1.

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.

NPI-2358, a Novel Vascular Disrupting Agent Blocks Growth and Angiogenesis in Multiple Myeloma Cells.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 3842-3842
Author(s):  
Dharminder Chauhan ◽  
Ajita V. Singh ◽  
Madhavi Bandi ◽  
Noopur Raje ◽  
Robert L Schlossman ◽  
...  
Keyword(s):  
Cell Lines ◽  
Annexin V ◽  
Vascular Endothelial ◽  
Caspase 9 ◽  
Migration Assays ◽  
Induced Apoptosis ◽  
Rpmi 8226 ◽  
Anti Tumor Activity

Abstract Abstract 3842 Poster Board III-778 Background and Rationale Vascular disrupting agents (VDAs) act via selectively disrupting established tumor vasculature and have shown remarkable clinical success as anti-cancer therapies. NPI-2358 is a novel VDA with a distinct structure and mechanism of action from other available VDAs. NPI-2358 binds to the colchicine-binding site of beta-tubulin preventing polymerization and disrupting the cytoplasmic microtubule network, thereby causing loss of vascular endothelial cytoskeletal function, and inducing cytotoxicity in cancer cells. Here, we examined the anti-angiogenic and anti-tumor activity of NPI-2358 in multiple myeloma (MM) cells using both in vitro and in vivo model systems. Material and Methods We utilized MM.1S, MM.1R, RPMI-8226, U266, and INA-6 human MM cell lines, as well as purified tumor cells from MM patients relapsing after prior anti-MM therapies. Cell viability/apoptosis assays were performed using MTT, trypan blue exclusion, and Annexin V/PI staining. Angiogenesis was measured in vitro using Matrigel capillary-like tube structure formation assays: Since human vascular endothelial cells (HUVECs) plated onto Matrigel differentiate and form capillary-like tube structures similar to in vivo neovascularization, this assay measures anti-angiogenic effects of drugs/agents. Migration assays were performed using transwell insert assays. Immunoblot analysis was performed using antibodies to caspase-8, caspase-9, caspase-3, PARP, Bcl-2, Bax, pJNK and GAPDH. Statistical significance was determined using a Student t test. Results Treatment of MM.1S, RPMI-8226, MM.1R, INA-6, and KMS-12BM with NPI-2358 for 24h induces a dose-dependent significant (P < 0.005) decrease in viability of all cell lines (IC50 range: 5-8 nM; n=3). To determine whether NPI-2358-induced decrease in viability is due to apoptosis, MM cell lines were treated with NPI-2358 for 24h; harvested, and analyzed for apoptosis using Annexin V/PI staining. A significant increase in NPI-2358-induced apoptosis was observed in all MM cell lines (% Annexin V+/PI- apoptotic cells: MM.1S, 48 ± 2.3%; MM.1R, 46.6 ± 3.1%; RPMI-8226, 61.7 ± 4.5%; and INA-6, 59.9 ± 3.2%; P < 0.05; n=3). Importantly, NPI-2358 decreased viability of freshly isolated MM cells from patients (IC50 range: 3-7 nM; P < 0.005), without affecting the viability of normal peripheral blood mononuclear cells, suggesting specific anti-MM activity and a favorable therapeutic index for NPI-2358. Examination of in vitro angiogenesis using capillary-like tube structure formation assay showed that even low doses of NPI-2358 (7 nM treatment for 12h; IC50: 20 nM at 24h) significantly decreased tubule formation in HUVECs (70-80% decrease; P < 0.05). Transwell insert assays showed a marked reduction in serum-dependent migration of NPI-2358-treated MM cells (42 ± 2.1% inhibition in NPI-2358-treated vs. control; P < 0.05). NPI-2358 at the concentrations tested (5 nM for 12h) in the migration assays did not affect survival of MM cells (> 95% viable cells). A similar anti-migration activity of NPI-2358 was noted against HUVEC cells (48 ± 1.7% decrease in migration; P < 0.05). Mechanistic studies showed that NPI-2358-induced apoptosis was associated with activation of caspase-8, caspase-9, caspase-3 and PARP. Importantly, treatment of MM.1S cells with NPI-2358 (5 nM) triggered phosphorylation of c-Jun amino-terminal kinase (JNK), a classical stress response protein, without affecting Bcl-2 family members Bax and Bcl-2. Blockade of JNK using dominant negative strategy markedly abrogated NPI-2358-induced apoptosis. Conclusion Our preclinical data provide evidence for remarkable anti-angiogenic and anti-tumor activity of NPI-2358 against MM cells, without significant toxicity in normal cells. Ongoing studies are examining in vivo anti-MM activity of NPI-2358 in animal models. Importantly, a Phase-1 study of NPI-2358 as a single agent in patients with advanced malignancies (lung, prostrate and colon cancer) has already established a favorable pharmacokinetic, pharmacodynamic and safety profile; and, a Phase-2 study of the combination of NPI-2358 and docetaxel in non-small cell lung cancer showed encouraging safety, pharmacokinetic and activity data. These findings, coupled with our preclinical studies, provide the framework for the development of NPI-2358-based novel therapies to improve patient outcome in MM. Disclosures: Chauhan: Nereus Pharmaceuticals, Inc: Consultancy. Lloyd:Nereus Pharmaceuticals, In: Employment. Palladino:Nereus Pharmaceuticals, Inc: Employment. Anderson:Nereus Pharmaceuticals, Inc: Consultancy.

Combined Inhibition of Wee1 and Poly(ADP Ribose) Polymerase1/2 Synergistically Inhibits Acute Myeloid Leukemia Cells By Enhancing DNA Damage and the Induction of Apoptosis

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 3621-3621 ◽  
Author(s):  
Jonathan C Snedeker ◽  
Tamara M Burleson ◽  
Raoul Tibes ◽  
Christopher C. Porter
Keyword(s):  
Flow Cytometry ◽  
Cell Proliferation ◽  
Dna Damage ◽  
Cell Lines ◽  
Conflicts Of Interest ◽  
Combination Index ◽  
Annexin V ◽  
Concomitant Treatment ◽  
Western Blots

Abstract Introduction: Successful treatment of AML remains dependent upon cytotoxic chemotherapy. However, traditional regimens are not well tolerated by older patients who are at highest risk of disease, and salvage rates after relapse are low, necessitating novel therapeutic strategies. Our groups identified Wee1 as a potential therapeutic target in AML, particularly in the context of concomitant treatment with cytarabine (Tibes et al, Blood, 2012; Porter et al, Leukemia, 2012). Wee1 inhibits CDK1&2 via phosphorylation thereby stalling cell cycle progression. One consequence of Wee1 inhibition/CDK1 activation is impairment of DNA repair via homologous recombination (Krajewska et al, Oncogene, 2013). Cells in which HR is impaired are dependent upon Parp1/2 function, and HR deficient cells are particularly sensitive to Parp1/2 inhibition. Therefore, we hypothesized that combined Wee1 and Parp1/2 inhibition may result in greater inhibition of AML cell proliferation and survival than either alone. Methods: Human AML cell lines, MV4-11 and Molm-13, and a mouse AML that expresses MLL-ENL/FLT3-ITD were cultured with various concentrations of a Wee1 inhibitor (AZ1775) and a Parp1/2 inhibitor (olaparib) and counted 72 hours later by propidium iodide exclusion and flow cytometry. In some experiments, cells were split into fresh media to recover for 72 more hours. Combination Index (CI) values were calculated by the method of Chou and Talalay. Apoptosis was measured using Annexin V/7AAD and flow cytometry. Western blots were used to confirm inhibition of CDK1/2 phosphorylation and to measure DNA damage induction (gamma-H2AX). Results: Combined inhibition of Wee1 and Parp1/2 was synergistic, as measured by cell numbers at 72 hours, in all 3 cell lines tested, with combination index values ranging from 0.3 to 0.9. When cells were allowed to recover after treatment, those treated by single agents were able to continue proliferating. However, those treated with the combination did not recover as well or at all, indicating greatly impaired proliferative capacity. Combined inhibition of Wee1 and Parp1/2 also resulted in a significant increase in apoptosis greater than either drug alone. Western blots for gamma-H2AX confirmed that the combination of Wee1 and Parp1/2 resulted in more DNA damage than either drug alone. Discussion: Combined inhibition of Wee1 and Parp1/2 results in greater inhibition of AML cell proliferation, DNA damage and apoptosis than either drug alone. Future studies will include experiments with primary patient samples, as well as in vivo trials combining Wee1 inhibition with Parp1/2 inhibition. These preliminary studies raise the possibility of rational combinations of targeted agents for leukemia in those for whom conventional chemotherapeutics may not be well tolerated. Disclosures No relevant conflicts of interest to declare.

scholarly journals Voruciclib, an Oral, Selective CDK9 Inhibitor, Enhances Cell Death Induced By the Bcl-2 Selective Inhibitor Venetoclax in Acute Myeloid Leukemia

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 1361-1361 ◽  
Author(s):  
Daniel A Luedtke ◽  
Yongwei Su ◽  
Holly Edwards ◽  
Lisa Polin ◽  
Juiwanna Kushner ◽  
...  
Keyword(s):  
Cell Lines ◽  
Myeloid Leukemia ◽  
Caspase 3 ◽  
Combination Index ◽  
Survival Rates ◽  
Annexin V ◽  
Antileukemic Activity ◽  
Induction Of Apoptosis ◽  
Induced Apoptosis

Abstract Introduction: Patients with acute myeloid leukemia (AML) face overall 5-year survival rates of 65% and 27% for children and adults, respectively, leaving significant room for improvement. Relapse remains a major contributor to such low overall survival rates, and leukemic stem cells (LSCs) that survive treatment are believed to be responsible for AML relapse. The anti-apoptotic protein Bcl-2 is overexpressed in bulk AML cells and LSCs and is associated with poor clinical outcomes. Thus, Bcl-2 represents a promising therapeutic target for the treatment of AML. Venetoclax (ABT-199) is a selective Bcl-2 inhibitor that has shown great potential for treating a number of malignancies, including AML. Venetoclax inhibits Bcl-2, preventing it from sequestering pro-apoptotic Bcl-2 family protein Bim, leading to Bim activated Bax/Bak, resulting in apoptosis. However, Mcl-1 can also sequester Bim and prevent apoptosis. We previously showed that directly targeting Mcl-1 can enhance the antileukemic activity of venetoclax (Luedtke DA, et al. Signal Transduct Target Ther. Apr 2017). Alternatively, we proposed that indirect targeting of Mcl-1 may preserve or enhance the antileukemic activity of venetoclax, and prevent resistance resulting from Mcl-1. It has been reported that inhibition of CDK9 can downregulate cell survival genes regulated by superenhancers, including Mcl-1, MYC, and Cyclin D1. One CDK9 inhibitor in clinical development, flavopiridol (alvocidib), has progressed to phase II clinical trials in AML. However, off target effects and dose-limiting toxicities remain a concern. Voruciclib is an oral, selective CDK inhibitor differentiated by its potent inhibition of CDK9 as compared to other CDK inhibitors. This selectivity may potentially circumvent toxicities resulting from inhibition of non-CDK targets like MAK and ICK that are inhibited by flavopiridol. Voruciclib has been shown in vitro to promote apoptosis and decrease Mcl-1 expression levels in chronic lymphocytic leukemia (CLL) cells (Paiva C, et al. PLOS One. Nov 2015) and inhibit tumor growth in mouse xenograft models of diffuse large B-cell lymphoma (DLBCL) in combination with venetoclax (Dey J. et al Scientific Reports. Dec 2017). Based on these data, voruciclib may downregulate Mcl-1 in AML cells and therefore synergistically enhance the antileukemic activity of venetoclax. Methods/Results: Culturing AML cell lines (THP-1, U937, MOLM-13, MV4-11, and OCI-AML3) and primary patient samples with various concentrations of voruciclib resulted in a concentration-dependent increase in Annexin V+ cells (2 μM voruciclib induced 13.8-55.8% Annexin V+ cells) along with increased levels of cleaved caspase 3 and PARP, demonstrating that voruciclib induces apoptosis in AML cells. Next, we tested the combination of voruciclib and venetoclax in AML cell lines and primary AML patient samples at clinically achievable concentrations. Annexin V/PI staining, flow cytometry analysis, and combination index calculation (using CalcuSyn software) revealed synergistic induction of apoptosis by voruciclib and venetoclax combination (combination index values for MV4-11, U937, THP-1, and MOLM-13 cells were <0.73; treatment with 2 µM voruciclib and venetoclax for 24 h resulted in >80% apoptosis). Importantly, synergy was observed in both venetoclax sensitive and resistant cell lines. This was accompanied by increased cleavage of caspase 3 and PARP. Lentiviral shRNA knockdown of Bak and Bax partially rescued AML cells from voruciclib-induced apoptosis, showing that voruciclib induces apoptosis at least partially through the intrinsic apoptosis pathway. However, Bak and Bax knockdown had little to no effect on induction of apoptosis by the combination treatment, indicating that there might be other molecular mechanisms underlying the synergistic interaction between the two agents. Treatment with the pan-caspase inhibitor Z-VAD-FMK partially rescued cells from combination treatment induced-apoptosis. Discussion: Collectively, these results demonstrate that voruciclib and venetoclax synergistically induce apoptosis in AML cells in vitro and reverse venetoclax resistance. Further studies to determine the mechanism of action and in vivo efficacy of this promising combination in AML xenografts and PDX models are underway. Disclosures Ge: MEI Pharma: Research Funding.

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