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Antiviral Research Feb 2016Influenza A viruses (IAVs) impact the public health and global economy by causing yearly epidemics and occasional pandemics. Several anti-IAV drugs are available and...
Influenza A viruses (IAVs) impact the public health and global economy by causing yearly epidemics and occasional pandemics. Several anti-IAV drugs are available and many are in development. However, the question remains which of these antiviral agents may allow activation of immune responses and protect patients against co- and re-infections. To answer to this question, we analysed immuno-modulating properties of the antivirals saliphenylhalamide (SaliPhe), SNS-032, obatoclax, and gemcitabine, and found that only gemcitabine did not impair immune responses in infected cells. It also allowed activation of innate immune responses in lipopolysaccharide (LPS)- and interferon alpha (IFNα)-stimulated macrophages. Moreover, immuno-mediators produced by gemcitabine-treated IAV-infected macrophages were able to prime immune responses in non-infected cells. Thus, we identified an antiviral agent which might be beneficial for treatment of patients with severe viral infections.
Topics: Amides; Antineoplastic Agents; Antiviral Agents; Cells, Cultured; Coinfection; Cytokines; Deoxycytidine; Humans; Immunity, Innate; Immunologic Factors; Indoles; Influenza A virus; Influenza, Human; Interferon-alpha; Lipopolysaccharides; Macrophages; Oxazoles; Phosphoproteins; Pyrroles; RNA, Viral; Salicylates; Thiazoles; Virus Replication; Gemcitabine
PubMed: 26738783
DOI: 10.1016/j.antiviral.2015.12.011 -
International Journal of Molecular... Mar 2019Several studies by our group and others have determined that expression levels of Bcl-2 and/or Bcl-xL, pro-survival molecules which are associated with chemoresistance,...
Obatoclax, a BH3 Mimetic, Enhances Cisplatin-Induced Apoptosis and Decreases the Clonogenicity of Muscle Invasive Bladder Cancer Cells via Mechanisms That Involve the Inhibition of Pro-Survival Molecules as Well as Cell Cycle Regulators.
Several studies by our group and others have determined that expression levels of Bcl-2 and/or Bcl-xL, pro-survival molecules which are associated with chemoresistance, are elevated in patients with muscle invasive bladder cancer (MI-BC). The goal of this study was to determine whether combining Obatoclax, a BH3 mimetic which inhibits pro-survival Bcl-2 family members, can improve responses to cisplatin chemotherapy, the standard of care treatment for MI-BC. Three MI-BC cell lines (T24, TCCSuP, 5637) were treated with Obatoclax alone or in combination with cisplatin and/or pre-miR-34a, a molecule which we have previously shown to inhibit MI-BC cell proliferation via decreasing Cdk6 expression. Proliferation, clonogenic, and apoptosis assays confirmed that Obatoclax can decrease cell proliferation and promote apoptosis in a dose-dependent manner. Combination treatment experiments identified Obatoclax + cisplatin as the most effective treatment. Immunoprecipitation and Western analyses indicate that, in addition to being able to inhibit Bcl-2 and Bcl-xL, Obatoclax can also decrease cyclin D1 and Cdk4/6 expression levels. This has not previously been reported. The combined data demonstrate that Obatoclax can inhibit cell proliferation, promote apoptosis, and significantly enhance the effectiveness of cisplatin in MI-BC cells via mechanisms that likely involve the inhibition of both pro-survival molecules and cell cycle regulators.
Topics: Cell Line, Tumor; Cell Proliferation; Cell Survival; Cisplatin; Cyclin D1; Cyclin-Dependent Kinase 4; Cyclin-Dependent Kinase 6; Dose-Response Relationship, Drug; Drug Synergism; Gene Expression Regulation, Neoplastic; Humans; Indoles; Neoplasm Invasiveness; Proto-Oncogene Proteins c-bcl-2; Pyrroles; Urinary Bladder; Urinary Bladder Neoplasms; bcl-X Protein
PubMed: 30875757
DOI: 10.3390/ijms20061285 -
Cancer Research Mar 2010Apoptosis induction by BH3 mimetics is a therapeutic strategy for human cancer. These mimetics exert single-agent activity in cells "primed" for cell death. Primed cells...
Apoptosis induction by BH3 mimetics is a therapeutic strategy for human cancer. These mimetics exert single-agent activity in cells "primed" for cell death. Primed cells are dependent upon antiapoptotic Bcl-2 proteins for survival and are characterized by the ability of the BH3 mimetic to induce cytochrome c release from their isolated mitochondria. Our aim was to examine the single-agent activity of obatoclax, a BH3 mimetic in cholangiocarcinoma cell lines. In clonogenic assays, inhibition of colony formation was observed by obatoclax treatment. Despite single-agent activity by obatoclax, the mitochondria from these cells did not release cytochrome c after incubation with this BH3 mimetic. However, immunofluorescence and cell fractionation studies identified Bax activation and translocation to mitochondria after treatment with obatoclax. shRNA targeted knockdown of Bax doubled the IC50 for obatoclax but did not abrogate its cytotoxicity, whereas knockdown of Bak did not alter the IC50. In a cell-free system, obatoclax induced an activating conformational change of Bax, which was attenuated by a site-directed mutagenesis of a previously identified protein activation site. Finally, the drug also elicited a significant in vivo response in a rodent model of this disease. In conclusion, single-agent obatoclax treatment results in Bax activation, which contributes, in part, to cell death in cholangiocarcinoma cells. These data indicate that BH3 mimetics may also function as direct activators of Bax and induce cytotoxicity in cells not otherwise primed for cell death.
Topics: Animals; Apoptosis; Cell Line, Tumor; Cholangiocarcinoma; Humans; Indoles; Male; Mitochondria; Pyrroles; Rats; Rats, Inbred F344; bcl-2-Associated X Protein
PubMed: 20160031
DOI: 10.1158/0008-5472.CAN-09-3535 -
Leukemia & Lymphoma 2015Obatoclax is a small molecule mimetic of the BH3 domain of BCL-2 family proteins. This phase 1 study combining obatoclax with FR was undertaken in chronic lymphocytic... (Clinical Trial)
Clinical Trial
Obatoclax is a small molecule mimetic of the BH3 domain of BCL-2 family proteins. This phase 1 study combining obatoclax with FR was undertaken in chronic lymphocytic leukemia (CLL) patients relapsed after at least one prior therapy. Obatoclax was given as a 3-h infusion on days 1 and 3 and escalated through three dose levels, with standard dose FR days 1-5. Thirteen patients were enrolled, with a median of two prior therapies. One dose-limiting toxicity (DLT) of a 2-week treatment delay for persistent grade 2-3 neutropenia was observed at the highest obatoclax dose (20 mg/m2), but no maximum tolerated dose (MTD) was reached. The overall response rate (ORR) was 85%, with 15% complete responses (CRs) by NCI-96 criteria and 54% by IWCLL 2008 criteria. Median time to progression was 20 months. It is concluded that obatoclax can be safely administered to relapsed CLL patients in combination with FR and shows promising clinical activity.
Topics: Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Biomarkers; Chromosome Aberrations; Combined Modality Therapy; Disease Progression; Female; Humans; Indoles; Leukemia, Lymphocytic, Chronic, B-Cell; Male; Middle Aged; Mutation; Neoplasm Staging; Pyrroles; Recurrence; Retreatment; Rituximab; Treatment Outcome; Vidarabine
PubMed: 25971907
DOI: 10.3109/10428194.2015.1048441 -
Blood Apr 2013Survival in infants younger than 1 year who have acute lymphoblastic leukemia (ALL) is inferior whether MLL is rearranged (R) or germline (G). MLL translocations confer...
Survival in infants younger than 1 year who have acute lymphoblastic leukemia (ALL) is inferior whether MLL is rearranged (R) or germline (G). MLL translocations confer chemotherapy resistance, and infants experience excess complications. We characterized in vitro sensitivity to the pan-antiapoptotic BCL-2 family inhibitor obatoclax mesylate in diagnostic leukemia cells from 54 infants with ALL/bilineal acute leukemia because of the role of prosurvival BCL-2 proteins in resistance, their imbalanced expression in infant ALL, and evidence of obatoclax activity with a favorable toxicity profile in early adult leukemia trials. Overall, half maximal effective concentrations (EC50s) were lower than 176 nM (the maximal plasma concentration [Cmax] with recommended adult dose) in 76% of samples, whether in MLL-AF4, MLL-ENL, or other MLL-R or MLL-G subsets, and regardless of patients' poor prognostic features. However, MLL status and partner genes correlated with EC50. Combined approaches including flow cytometry, Western blot, obatoclax treatment with death pathway inhibition, microarray analyses, and/or electron microscopy indicated a unique killing mechanism involving apoptosis, necroptosis, and autophagy in MLL-AF4 ALL cell lines and primary MLL-R and MLL-G infant ALL cells. This in vitro obatoclax activity and its multiple killing mechanisms across molecular cytogenetic subsets provide a rationale to incorporate a similarly acting compound into combination strategies to combat infant ALL.
Topics: Antineoplastic Agents; Apoptosis; Autophagy; Cell Line, Tumor; Drug Resistance, Neoplasm; Gene Expression Regulation, Leukemic; Histone-Lysine N-Methyltransferase; Humans; Indoles; Infant; Infant, Newborn; Myeloid-Lymphoid Leukemia Protein; Necrosis; Oncogene Proteins, Fusion; Precursor Cell Lymphoblastic Leukemia-Lymphoma; Proto-Oncogene Proteins c-bcl-2; Pyrroles
PubMed: 23393050
DOI: 10.1182/blood-2012-04-425033 -
Acta Pharmacologica Sinica Aug 2021Proteasome inhibitors, bortezomib (BTZ), and carfilzomib (CFZ) are approved drugs for hematological malignancies, but lack anticancer activities against most solid...
Proteasome inhibitors, bortezomib (BTZ), and carfilzomib (CFZ) are approved drugs for hematological malignancies, but lack anticancer activities against most solid tumors. Small cell lung cancer (SCLC) is a very aggressive neuroendocrine carcinoma of the lungs demanding effective therapy. In this study we investigated whether BTZ or CFZ combined with obatoclax (OBX), an antagonist for MCL-1 and a pan-BCL family inhibitor, could cause synergistic growth inhibition of SCLC cells. We showed that combined application of BTZ or CFZ with OBX caused synergistic growth inhibition of human SCLC cell lines (H82, H526, DMS79, H196, H1963, and H69) than single agent alone. Both BTZ-OBX and CFZ-OBX combinations displayed marked synergism on inducing apoptosis (~50% increase vs BTZ or CFZ alone). A comprehensive proteomics analysis revealed that BTZ preferentially induced the expression of MCL-1, an antiapoptotic protein, in SCLC cells. Thus, proteasome inhibitor-OBX combinations could specifically induce massive growth inhibition and apoptosis in SCLC cells. Subsequent proteome-wide profiling analysis of activated transcription factors suggested that BTZ- or CFZ-induced MCL-1 upregulation was transcriptionally driven by FOXM1. In nude mice bearing in SCLC H82 xenografts, both BTZ-OBX, and CFZ-OBX combinations exhibited remarkable antitumor activities against SCLC tumors evidenced by significant reduction of tumor size and the proliferation marker Ki-67 signals in tumor tissues as compared with single agent alone. Thus, proteasome inhibitor-OBX combinations are worth immediate assessments for SCLC in clinical settings.
Topics: Animals; Antineoplastic Agents; Apoptosis; Bortezomib; Cell Line, Tumor; Drug Synergism; Forkhead Box Protein M1; HEK293 Cells; Humans; Indoles; Lung Neoplasms; Mice, Nude; Myeloid Cell Leukemia Sequence 1 Protein; Oligopeptides; Proteasome Inhibitors; Pyrroles; Small Cell Lung Carcinoma; Up-Regulation; Xenograft Model Antitumor Assays; Mice
PubMed: 33139838
DOI: 10.1038/s41401-020-00544-w -
Blood Jun 2012Interactions between the multikinase inhibitor sorafenib and the BH3-mimetic obatoclax (GX15-070) were examined in human acute myeloid leukemia (AML) cells. Treatment...
Interactions between the multikinase inhibitor sorafenib and the BH3-mimetic obatoclax (GX15-070) were examined in human acute myeloid leukemia (AML) cells. Treatment with sorafenib/obatoclax induced pronounced apoptosis in and reduced the clonogenic growth of multiple AML lines and primary AML cells but not normal CD34(+) cells. Sorafenib triggered rapid and pronounced Mcl-1 down-regulation accompanied by enhanced binding of Bim to Bcl-2 and Bcl-xL, effects that were abolished by obatoclax coadministration. Notably, shRNA knockdown of Bim, Bak, or Bax, but not Noxa, significantly attenuated obatoclax/sorafenib lethality, whereas ectopic expression of Mcl-1 exerted a protective effect. Furthermore, exposure of leukemia cells to sorafenib and obatoclax markedly induced autophagy, reflected by rapid and pronounced LC3 processing and LC3-green fluorescent protein (GFP) punctate formation. Multiple autophagy inhibitors or VPS34 knockdown, significantly potentiated sorafenib/obatoclax lethality, indicating a cytoprotective role for autophagy in this setting. Finally, studies in a xenograft mouse model revealed that combined sorafenib/obatoclax treatment markedly reduced tumor growth and significantly prolonged survival in association with Mcl-1 down-regulation and apoptosis induction, whereas agents administered individually had only modest effects. These findings suggest that combining sorafenib with agents that inhibit Mcl-1 and Bcl-2/Bcl-xL such as obatoclax may represent a novel and potentially effective strategy in AML.
Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Apoptosis Regulatory Proteins; Bcl-2-Like Protein 11; Benzenesulfonates; Cells, Cultured; Drug Synergism; Female; HL-60 Cells; Humans; Indoles; Leukemia, Myeloid; Membrane Proteins; Mice; Mice, Nude; Niacinamide; Phenylurea Compounds; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-bcl-2; Pyridines; Pyrroles; Sorafenib; U937 Cells; Up-Regulation; Xenograft Model Antitumor Assays
PubMed: 22446485
DOI: 10.1182/blood-2011-09-378141 -
Molecular Cancer Therapeutics May 2012Interactions between the irreversible proteasome inhibitor carfilzomib and the pan-BH3 mimetic obatoclax were examined in germinal center (GC)- and activated...
Interactions between the irreversible proteasome inhibitor carfilzomib and the pan-BH3 mimetic obatoclax were examined in germinal center (GC)- and activated B-cell-diffuse large B-cell lymphoma (ABC-DLBCL) cells. Cotreatment with minimally toxic concentrations of carfilzomib (i.e., 2-6 nmol/L) and subtoxic concentrations of obatoclax (0.05-2.0 μmol/L) synergistically increased apoptosis in multiple DLBCL cell lines and increased lethality toward primary human DLBCL but not normal CD34(+) cells. Synergistic interactions were associated with sharp increases in caspase-3 activation, PARP cleavage, p-JNK induction, upregulation of Noxa, and AKT dephosphorylation. Combined treatment also diminished carfilzomib-mediated Mcl-1 upregulation whereas immunoprecipitation analysis revealed reduced associations between Bak and Mcl-1/Bcl-xL and Bim and Mcl-1. The carfilzomib/obatoclax regimen triggered translocation, conformational change, and dimerization of Bax and activation of Bak. Genetic interruption of c-jun-NH(2)-kinase (JNK) and Noxa by short hairpin RNA knockdown, ectopic Mcl-1 expression, or enforced activation of AKT significantly attenuated carfilzomib/obatoclax-mediated apoptosis. Notably, coadministration of carfilzomib/obatoclax sharply increased apoptosis in multiple bortezomib-resistant DLBCL models. Finally, in vivo administration of carfilzomib and obatoclax to mice inoculated with SUDHL4 cells substantially suppressed tumor growth, activated JNK, inactivated AKT, and increased survival compared with the effects of single-agent treatment. Together, these findings argue that a strategy combining carfilzomib and obatoclax warrants attention in DLBCL.
Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Apoptosis Regulatory Proteins; Bcl-2-Like Protein 11; Cell Line, Tumor; Drug Synergism; Germinal Center; Histones; Humans; Indoles; Lymphoma, Large B-Cell, Diffuse; MAP Kinase Kinase 4; Membrane Proteins; Mice; Mice, Nude; Myeloid Cell Leukemia Sequence 1 Protein; Oligopeptides; Proteasome Endopeptidase Complex; Proteasome Inhibitors; Protein Binding; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-akt; Proto-Oncogene Proteins c-bcl-2; Pyrroles; Xenograft Model Antitumor Assays; bcl-2 Homologous Antagonist-Killer Protein; bcl-2-Associated X Protein
PubMed: 22411899
DOI: 10.1158/1535-7163.MCT-12-0021 -
Viruses Jun 2020As of June 2020, the number of people infected with severe acute respiratory coronavirus 2 (SARS-CoV-2) continues to skyrocket, with more than 6.7 million cases...
As of June 2020, the number of people infected with severe acute respiratory coronavirus 2 (SARS-CoV-2) continues to skyrocket, with more than 6.7 million cases worldwide. Both the World Health Organization (WHO) and United Nations (UN) has highlighted the need for better control of SARS-CoV-2 infections. However, developing novel virus-specific vaccines, monoclonal antibodies and antiviral drugs against SARS-CoV-2 can be time-consuming and costly. Convalescent sera and safe-in-man broad-spectrum antivirals (BSAAs) are readily available treatment options. Here, we developed a neutralization assay using SARS-CoV-2 strain and Vero-E6 cells. We identified the most potent sera from recovered patients for the treatment of SARS-CoV-2-infected patients. We also screened 136 safe-in-man broad-spectrum antivirals against the SARS-CoV-2 infection in Vero-E6 cells and identified nelfinavir, salinomycin, amodiaquine, obatoclax, emetine and homoharringtonine. We found that a combination of orally available virus-directed nelfinavir and host-directed amodiaquine exhibited the highest synergy. Finally, we developed a website to disseminate the knowledge on available and emerging treatments of COVID-19.
Topics: Amodiaquine; Animals; Antiviral Agents; Betacoronavirus; COVID-19; Caco-2 Cells; Cell Line, Tumor; Chlorocebus aethiops; Coronavirus Infections; Drug Therapy, Combination; Emetine; HEK293 Cells; HT29 Cells; Homoharringtonine; Humans; Immune Sera; Immunization, Passive; Indoles; Nelfinavir; Neutralization Tests; Pandemics; Pneumonia, Viral; Pyrans; Pyrroles; SARS-CoV-2; Vero Cells; COVID-19 Serotherapy
PubMed: 32545799
DOI: 10.3390/v12060642 -
Cancer Research May 2008In this study, we investigated the mechanism of apoptosis induction of obatoclax (GX15-070), a novel Bcl-2 homology domain-3 (BH3) mimetic, in acute myeloid leukemia...
In this study, we investigated the mechanism of apoptosis induction of obatoclax (GX15-070), a novel Bcl-2 homology domain-3 (BH3) mimetic, in acute myeloid leukemia (AML) cell lines and primary AML samples. Obatoclax inhibited cell growth of HL-60, U937, OCI-AML3, and KG-1 cell lines. Apoptosis induction contributed to the observed antiproliferative effects at concentrations of this agent that mirror its affinity for antiapoptotic Bcl-2 proteins. We show that obatoclax can promote the release of cytochrome c from isolated leukemia cell mitochondria and that apoptosis induced by this agent is preceded by the release of Bak from Mcl-1, liberation of Bim from both Bcl-2 and Mcl-1, and the formation of an active Bak/Bax complex. Notably, apoptosis was diminished, but not fully prevented, in the absence of Bak/Bax or Bim, suggesting that obatoclax has additional targets that contribute to its cytotoxicity. At growth inhibitory doses that did not induce apoptosis or decrease viability, obatoclax induced an S-G(2) cell-cycle block. Obatoclax induced apoptosis in AML CD34+ progenitor cells with an average IC(50) of 3.59 +/- 1.23 micromol/L although clonogenicity was inhibited at concentrations of 75 to 100 nmol/L. Obatoclax synergized with the novel BH3 mimetic ABT-737 to induce apoptosis in OCI-AML3 cells and synergistically induced apoptosis in combination with AraC in leukemic cell lines and in primary AML samples. In conclusion, we show that obatoclax potently induces apoptosis and decreases leukemia cell proliferation and may be used in a novel therapeutic strategy for AML alone and in combination with other targeted agents and chemotherapeutics.
Topics: Animals; Antineoplastic Agents; Apoptosis; AraC Transcription Factor; Biomimetics; Biphenyl Compounds; Cells, Cultured; Drug Synergism; HL-60 Cells; Humans; Indoles; Leukemia; Mice; Mice, Knockout; Myeloid Cell Leukemia Sequence 1 Protein; Neoplasm Proteins; Nitrophenols; Piperazines; Protein Structure, Tertiary; Proto-Oncogene Proteins c-bcl-2; Pyrroles; Sulfonamides; Tumor Stem Cell Assay; U937 Cells
PubMed: 18451169
DOI: 10.1158/0008-5472.CAN-07-1919