bluuebunny/crossref_metadata_2025_split huggingface dataset:
Activation of mTOR Signaling Pathway Contributes to Tumoral Cell Survival in ALK-Positive Anaplastic Large Cell Lymphoma.
Authors: Vega Francisco , Medeiros L. Jeffrey , Atwell Coralyn , Cho Jeong Hee , Tian Ling , Claret Francois-Xavier , Rassidakis George Z. 
Published: April 2020

Abstract
Anaplastic lymphoma kinase (ALK)-positive anaplastic large cell lymphoma (ALCL) frequently carries the t(2;5)(p23;q35) resulting in aberrant expression of nucleophosmin (NPM)-ALK. Previously, NPM-ALK has been shown to activate phosphatidylinositol 3-kinase (PI3K) and its downstream effector, the serine/threonine kinase AKT. Recently, we have shown that mTOR signaling proteins are activated in ALK-positive ALCL tumors and that mTOR activation depends, at least in part, on activation of AKT (Lab Invest2005; 85: 255A). In this study, we investigate the biological effects of inhibition of mTOR on two ALK-positive ALCL cell lines, Karpas 299 and SU-DHL1. For this purpose, we used rapamycin to inhibit mTOR-raptor complex and mTOR-specific small interfering RNA (siRNA) to silence the endogenous mtor gene. Treatment with rapamycin, resulted in a marked concentration-dependent decrease of phosphorylated (p)-mTOR, and its downstream targets, p-p70S6K, p-S6K, p-4E-BP1 and total eIF4E. Similarly, silencing the expression of mtor resulted in a decrease in the activation/phosphorylation level of these proteins as well as in the level of p-AKT. Both treatments induced apoptosis and cell cycle arrest in both ALK-positive ALCL cell lines as demonstrated by trypan blue exclusion, annexin V staining, BrdU incorporation, and cell cycle studies. There was a concentration-dependent decrease in the anti-apoptotic proteins BCL-2, BCL-XL, MCL-1 and c-FLIP (L and S) with increasing concentrations of rapamycin or after mTOR siRNA treatment. The cyclin dependent kinase inhibitors p21waf1 and p27kip1 and underphosphorylated (Un-p)-RB protein were upregulated, after treatment with rapamycin or after mTOR siRNA treatment. In conclusion, we provide evidence that inhibition of mTOR induces cell cycle arrest and apoptosis in ALK-positive ALCL cells. The decrease of p-AKT by silencing mtor suggests that mTOR is necessary to activate AKT in ALK-positive ALCL, and thus, mTOR can function as a feedback signal activity of its own pathway.
Initial Safety and Efficacy Results of a Second-Generation Humanized Anti-CD20 Antibody, IMMU-106 (hA20), in Non-Hodgkin’s Lymphoma.
Authors: Morschhauser Franck , Leonard John P. , Coiffier Bertrand , Petillon Marie-Odile , Coleman Morton , Bahkti Amina , Sapra Puja , Teoh Nick , Wegener William A. , Horak Ivan D. , Goldenberg David M. 
Published: April 2020

Abstract
Background. Infusion reactions, prolonged infusion times and immunogenicity of the chimeric anti-CD20 antibody, rituximab, may in part be related to its murine component. The humanized anti-CD20 antibody, IMMU-106 (hA20), may offer potential advantages because only the CDRs are of murine origin and the remaining &gt;90% human framework regions are identical to humanized anti-CD22 IgG1 antibody epratuzumab, whose safety and short infusion times have been reported.
Methods. An open-label, multicenter, phase I/II, dose escalation study conducted in patients with recurrent B cell lymphoma to establish the safety, tolerance, pharmacokinetics, and immunogenicity of hA20 administered once weekly for 4 doses.
Results. Twenty patients (11 M/9 F, 40–81 y.o) with grade 1–2 follicular (n=16) or other CD20+ B-cell lymphomas (mantle cell, small lymphocytic, marginal zone x 2) were enrolled in the dose escalation portion of this study, receiving 120 mg/m2 (n=7), 200 mg/m2 (n=6), 375 mg/m2 (n=4) or 750 mg/m2 (n=3) weekly x 4. These patients had previously received 1-7 prior therapies (median, 2.5), including treatments with one (n=12) or 2–4 (n=6) rituximab-containing regimens (without progression within 6 months). Five patients (25%) had grade 1–2 infusion reactions predominantly with first hA20 infusion. Median infusion times for 375 mg/m2 of hA20 were 3.3 hours for first infusion, 2.0 hours for subsequent infusions, and were generally shorter at lower doses. Standard laboratory values obtained at each infusion were generally observed to be within normal limits, and human anti-human antibody (HAHA) serum evaluations are negative to date. Peripheral blood B-cell depletion occurred after first infusion and persisted for samples obtained up to 12 weeks following fourth infusion with analysis ongoing. Pharmacokinetic results after first and fourth infusions demonstrate a mean antibody serum half-life of 5.3 ± 5.3 and 12.0 ± 8.7 days, respectively. To date, of 15 pts with at least one post-treatment assessments now completed, there are at least 8 objective responses (53%) by Cheson criteria, including 6 patients (40%) with complete responses [CR, CRu] at a median follow-up of 12 weeks. Complete responses have been observed at all dose levels, including 3/7 patients receiving 120 mg/m2/wk.
Conclusion. This study demonstrates the safety, tolerability, and preliminary efficacy of this humanized anti-CD20 antibody administered weekly for 4 doses, mostly to patients with follicular lymphomas who relapsed after rituximab-containing regimens. The demonstration of CRs, tolerability, and relatively short infusion times is encouraging. This study is continuing and expanding to assess the durability of responses and the optimal dose for subsequent studies.
Long-Term Follow-Up of Patients Treated in a Phase 2 Trial with MyVax® Personalized Immunotherapy (Recombinant Id-KLH with GM-CSF) after Chemotherapy as Initial Treatment for Follicular Non-Hodgkin’s Lymphoma (NHL).
Authors: Timmerman John M. , Vose Julie , Levy Ronald , Mayo Martha , Denney Dan 
Published: April 2020

Abstract
Background: The tumor-specific variable regions of the clonal immunoglobulin (idiotype or Id) expressed by malignant B cell NHL can be used as a target for active immunotherapy. MyVax® Personalized Immunotherapy is a patient-specific, recombinant Id protein conjugated to Keyhole Limpet Hemocyanin (Id-KLH) and administered with Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF). Several Phase 2 clinical trials have been conducted to determine the immunogenicity of MyVax® Personalized Immunotherapy. Patients and
Methods: The patients all had previously untreated follicular lymphoma and achieved at least a partial response to either CVP chemotherapy (16 patients) or CVP + CHOP chemotherapy (5 patients) to be eligible to receive 5 series of immunizations with MyVax® Personalized Immunotherapy. Each immunization series consisted of MyVax® Personalized Immunotherapy administered SQ on Day 1 and GM-CSF alone on Days 2–4. The immunizations were administered over 24 weeks. The first 4 immunization series were administered every 4 weeks. The 5th immunization series was administered 12 weeks after the 4th immunization.
Results: There were a total of 21 evaluable patients in the study. Both cellular and humoral immune anti-idiotype responses (IRs) were elicited using this treatment schedule. Thirteen of the 21 patients (62%) mounted an anti-idiotype immune response. Ten of the 21 patients mounted a humoral anti-idiotype response while 7 of 16 patients evaluated mounted a cellular anti-idiotype response. Immunizations with MyVax® Personalized Immunotherapy appear to be safe and well tolerated. Adverse events reported in this trial were mostly mild to moderate and transient in nature. Follicular Lymphoma International Prognostic Index (FLIPI) scores for these patients indicate that most of the patients were in the intermediate or high-risk categories. The median follow-up is over 5.5 years in this trial. The median time to disease progression was 37.7 months measured from the end of chemotherapy. Ten of the 21 patients in this trial remain progression free between 47 months and 71 months post chemotherapy as of their last follow-up. Four of the patients that remain in remission are in the high risk category by FLIPI score.
Conclusions and Discussion: These results suggest that patients with a poorer prognosis according to their FLIPI score can achieve significant remissions following treatment with MyVax® Personalized Immunotherapy. MyVax® Personalized Immunotherapy is currently in a late-stage Phase 3 trial.
Atiprimod Blocks STAT3 and STAT5 Phosphorylation, Inhibits Proliferation, and Induces Apoptosis in Acute Myeloid Leukemia (AML) but Not Normal Cells.
Authors: Faderl Stefan , Ferrajoli Alessandra , Harris David , Van Quin , Kantarjian Hagop M. , Estrov Zeev 
Published: April 2020

Abstract
Cytokines and growth factors stimulate AML cell proliferation by activating various signaling pathways and high levels of cytokines have been associated with poor prognosis. Blocking signal transduction of cytokine-stimulated pathways may therefore inhibit AML growth and proliferation. Atiprimod is a cationic amphiphilic azaspirane. Although their mechanisms of action are not completely understood, azaspiranes were demonstrated among others to downregulate various cytokine receptors such as for interleukin (IL)-1, IL-2, IL-6, interferon-γ, and tumor necrosis factor-α. Owing to this spectrum of activities, we hypothesized that atiprimod inhibits activation of intracellular signaling pathways in AML cells resulting in apoptosis and growth inhibition. We first studied the antiproliferative effect of atiprimod on 5 AML cell lines (K562, HL-60, KG-1, OCIM2, OCI/AML3) using the MTT assay. Cells were incubated for 72 hours without and with increasing concentrations of atiprimod (1, 2, 3, and 4 μM), then harvested and their metabolic activity and viability determined as optical density measurements. To corroborate the results, we also studied the effect of atiprimod on OCIM2 cells using a clonogenic cell line assay. Next we determined expression of Stat3 and Stat5, as well as Phospho-stat3 and phospho-stat5 in the K562 cells by Western Immunoblotting where cells were incubated in the absence and presence of increasing atiprimod concentrations (0.5, 1, 2, 3, 4 μM). We further evaluated induction of apoptosis of OCIM2 and K562 cells following incubation with atiprimod at 1 and 4 μM using the annexin V-FITC assay and finally analyzed caspase 3 and PARP cleavage in K562 cells at atiprimod concentrations of 0.5, 1, 2, 3, and 4 μM using Western Immunoblotting. To demonstrate the effect of atiprimod on marrow cells from AML patients and healthy volunteers we incubated marrow cells with atprimod at increasing concentrations and used the blast colony assay to measure inhibition of proliferation. Our results demonstrate that: 1) atiprimod inhibits proliferation of AML cell lines and AML blast proliferation from patient samples, but not significantly normal hematopoietic progenitors from samples of healthy controls; 2) atiprimod inhibits phosphorylation of Stat 3 and 5; and 3) atiprimod induces apoptosis in OCIM2 and K562 cells by cleavage of caspase 3 and PARP. In summary, our data suggest that atiprimod inhibits phopshorylation of Stat 3 and 5, induces caspase-dependent apoptosis, and blocks AML cell proliferation. Further evaluation of atiprimod in clinical trials of AML and MDS should be considered.
RNA Silencing of Aurora Kinase Genes Sensitizes Human Leukemia Cells to the Ara-C-Induced Cell Death Via Caspase-Independent Pathway.
Authors: Min Yoo-Hong , Lee Jin Koo , Eom Ju In , Park In Hae , Park Sun Young , Kim Yuri , Kim Jin Seok , Cheong June-Won 
Published: April 2020

Abstract
Aurora kinases play critical roles in chromosome segregation and cell division. Furthermore, Aurora A and B kinases are both frequently amplified and overexpressed in a various kinds of human cancers including leukemia disorders. To address its possibility as a therapeutic target for leukemia, we employed the RNA interference technique to knockdown Aurora kinase gene expression and analyzed its effect on the cell cycle distribution and the chemotherapy-induced cell death in leukemia cells. The expression of Aurora kinase A (AURKA) and Aurora kinase B (AURKB) was observed in all the leukemia cell lines evaluated and 15 out of 18 cultured leukemic cell specimens obtained from untreated patients with acute myeloid leukemia (AML). An arrest in the G(2)/M phase 24 h after specific knockdown of AURKA was shown in U937 leukemia cells. Following the silencing of AURKA, we observed a striking increase in the proportion of cells in the S phase, tetraploid state, and showing multi-nucleated morphologic changes. Cell death was observed in 17.0 ± 0.9% and 20.1 ± 2.5% of U937 cells after AURKA and AURKB silencing, respectively. The proportion of cells in the subG(0)/G(1) phase was 23% and 11% with AURKA and AURKB silencing, respectively. Although the disruption of mitochondrial membrane potential was observed after AURKA or AURKB silencing in U937 cells, the cleavage of caspase-3, -8, -9, and PARP was not observed in the apoptotic cells. Pretreatment of U937 cells with the caspase-3 inhibitor, DEVD-CHO, did not abrogate the AURKA or AURKB silencing-induced cell death. The U937 leukemia cells are resistant to Ara-C-induced cell death. However, we observed a striking synergistic enhancement of the cytotoxicity of Ara-C (10 μM), an important antimetabolic chemotherapeutic agent used for acute leukemia, by the RNA interference-mediated knockdown of AURKA and AURKB through a caspase-independent manner in U937 cells. Collectively, we demonstrate that the specific inhibition of either AURKA or AURKB can potentially regulate the cell cycle distribution of leukemia cells and induce synergistic interaction with Ara-C for inducing the cell death through the mechanism of mitotic catastrophe. These results indicate that Aurora kinase inhibition provides a novel approach for the treatment of human acute leukemia.
An Acidic Peptide Inhibits the Interleukin-6-Induced Activities of the Src Family Kinases Hck, Lyn and Fyn in Myeloma Cells.
Authors: Hausherr Amparo , Tavares Rosario , Hallek Michael , Krause Guenter F. 
Published: April 2020

Abstract
Background: Src Family Kinases (SFKs) play pivotal roles in normal B-cell development and in B-cell neoplasias. Our aim is to elucidate the roles of SFKs in signaling cascades resulting in cell proliferation or anti-apoptosis in multiple myeloma (MM). The pleiotropic cytokine interleukin-6 (IL6) is one of the major growth factors for MM cells. We have previously shown that IL6 induces the activation of the SFKs Hck, Lyn and Fyn and that Hck is associated with the IL6R beta chain (gp130) via an acid domain (AD) in gp130.
Aim: We observed that an 18mer peptide (18AD), which is derived from the AD, inhibited the IL-6-dependent growth of myeloma cells. In order to develop a lead structure for small molecule inhibitors we wish to elucidate the cellular and molecular effects of peptide 18AD.
Results: On the cellular level, 50–100μM of a membrane-permeable myristoylated peptide 18AD inhibited factor-dependent proliferation in 7TD-1 (mouse) and INA-6 (human) cells by ~75%. Taking the percentage of annexinV-stained cells after IL6-withdrawal as the reference value for the level of maximal apoptosis, treatment of 7TD1 and INA-6 cells with peptide 18AD resulted in 100 and 60 % of the respective percentages of apoptotic cells. A control peptide (18sc) with an identical amino acid composition but an arbitrarily scrambled sequence had no effect on proliferation and apoptosis. Similar effects of peptides 18AD and 18sc were observed in Baf-EH cells, which overexpress a chimeric erythropoietin receptor-gp130 and human Hck and grew in an erythropoietin dependent manner. Peptide 18AD had no significant growth inhibiting effects on BaF-HE cells cultured in the presence of IL3 or on factor-independent OKT1 hybridoma cells. In 7TD1 cells the expression of a kinase-inactive Hck mutant lead to a reduced proliferative response to IL6. On the molecular level, immunoprecipitation experiments in 7TD1 cells showed that peptide 18AD decreased the complex formation between Hck and gp130 in a concentration dependent way. Immunocomplex kinase assays in INA-6 cells showed that the IL6 induced activation of Hck, Lyn and Fyn was blocked by peptide 18AD, but not by peptide 18sc.
Conclusion: We characterized peptide 18AD, which inhibits the association of Hck and gp130 as well as IL6-induced SFK activity. Thus, the observed anti-proliferative and pro-apoptotic effects of peptide 18AD may be due to inhibition of SFK-mediated pathways.
Histone Deacetylase Inhibitors LBH589 and LAQ824 Deplete Ezh2 and Associated Polycomb Repressive Complex 2/3 Proteins Resulting in Downregulation of HOXA9 and MEIS1 Expression in Human Acute Leukemia Cells.
Authors: Fiskus Warren , Pranpat Michael , Bali Purva , Kumaraswamy Sandhya , Boyapalle Sandhya , Rocha Kathy , Balasis Maria , Atadja Peter , Bhalla Kapil 
Published: April 2020

Abstract
Human enhancer of Zeste homolog (Ezh2) protein belongs to Polycomb Repressive Complex (PRC) 2, which also includes Eed and Suz12. Ezh2 has been shown to promote cellular transformation, and increased Ezh2 expression has been strongly correlated with the invasiveness of prostate and breast cancers. The enzymatically-active Ezh2-containing, PRC2 complex possesses histone methyl transferase (HMTase) activity mediated by the SET domain of Ezh2, which is involved in the methylation of histone (H) 3, lysine (K)-27 and −9. Through this, the PRC2 complex regulates the expression of homeobox domain containing HOX family of transcription factors including HOXA9 and MEIS1, which have been shown to be involved in human leukemogenesis. Co-expression of HOXA9 and MEIS1 is common in acute myeloid leukemia and collaborates in the leukemogenesis. In the present studies, we determined the effect of hydroxamate histone deacetylase inhibitors LBH589 and LAQ824 on Ezh2 and PRC2 complex proteins and their activity in the cultured (K562, LAMA-84, U937 and HL-60) and primary human AML cells. Exposure to 10 to 100 nM of LBH589 or LAQ824 for 24 hours, in a dose dependent manner depleted the protein levels of Ezh2, as well as reduced Suz12 and Eed levels in the cultured and primary leukemia cells. This was associated with decreased levels of the tri- and dimethylated K27 and increased acetylation of K27, both on H3. Correspondingly, these H3 modifications were associated with a significant decline in the levels of HOXA9 and MEIS1. As has been previously reported, treatment with LBH589 and LAQ824 induced p21, as well as caused cell cycle growth arrest in the G1 phase and apoptosis of the cultured and primary AML cells. We next determined whether knockdown of Ezh2 by siRNA to Ezh2 also induces growth inhibitory and cytotoxic effects against the leukemia cells. In the cultured and primary acute leukemia cells, knockdown of Ezh2 expression (by ~80%) by Ezh2 siRNA, but not by the control siRNA, was associated with depletion of Suz12 levels and increased H3K27 acetylation. This was associated with increase in the % of cells in the G1 phase of the cell cycle and significant inhibition of their clonogenic survival in colony growth assays. Co-treatment with LBH589 and siRNA to Ezh2 caused further decline in the Ezh2 levels and increased loss of clonogenic survival of the leukemia cells. These findings suggest that down modulation of Ezh2 and PRC2 complex and its HMTase activity may inhibit clonogenic survival of human acute myeloid leukemia cells. Additionally, combined effect of the knockdown of Ezh2 and its activity along with treatment with LBH589 or LAQ824 may have an improved anti-leukemia efficacy, especially against human AML where HOXA9 and MEIS1 genes are deregulated.
Proteasome Inhibition Sensitizes Leukemic Cells to Anthracyclin-Induced Apoptosis by Increasing the Expression of Bim and Bax Pro-Apoptotic Proteins.
Authors: Pigneux Arnaud , Mahon François X. , Moreau-Gaudry François , Néré Marie L. , Lacombe Francis , Reiffers Josy , Praloran Vincent , Belloc Francis 
Published: April 2020

Abstract
NF-k B is constitutively activated in the majority of acute myelogenous leukemia (AML) specimens. Anthracyclines used in AML treatment can activate NF-k B and inhibit apoptosis through synthesis of IAPs upregulation. Because proteasome activity is necessary for NF-k B activation and p53 degradation, inhibitors of the proteasome have been proposed as pro-apoptotic agents to sensitize leukemic blast cells to anthracycline chemotherapy. Apoptosis was quantified in THP-1 cells, incubated with increasing concentrations of (IDA) alone or in association with a low concentration (0.25 μM) of MG132 as a proteasome inhibitor. A low apoptotic rate was found with either MG132 or IDA alone with a range of 5 to 20 ng/ml. The combination of both drugs induced a percentage of apoptotic cells which was significantly higher than the addition of the effects of both drugs separately (p&lt;0.01). A low concentration of IDA (5ng/ml) induced, in the presence of MG132 as much apoptosis as 20 ng/ml of IDA alone. Above 40 ng/ml of IDA, the sensitizing effect of MG132 was no more significant. This shows that proteasome inhibition lowers the threshold of sensititvity of THP-1 cells to IDA-induced apoptosis. Such a sensitization was not found in a MG132-resistant THP-1 derived cell line. This difference was not related to the uptake of the drug since no difference in IDA incorporation by THP-1 cells was found in the presence or the absence of MG132. Western blot analysis of I-k B phosphorylation and degradation failed to show any difference between MG132 and control-treated cells. Conversely increased expression of Bax and Bim pro-apoptotic proteins was evidenced. The increase in Bim precedes the induction of apoptosis and participates in Idarubicin-induced apoptosis. Bortezomib gave the same results for apoptosis induction and synergistic effect with IDA, increased expression of Bax and Bim pro-apoptotic proteins was also evidenced. MG132 also potentiated IDA-induced apoptosis in primary blast cells from 22 AML patients while no effect of MG132 was found on the IDA-induced apoptosis normal lymphocytes, PHA-stimulated lymphocytes, normal cord blood CD34+ cells and bone marrow normal myeloid cells. These data confirm that proteasome inhibition induces a specific sensitization of leukemic cells to IDA and suggest that an increase in the pro-apoptotic potential (Bim, Bax) are involved in the process.