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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 -
Chemical Science Jul 2022Small molecules and antibodies are normally considered separately in drug discovery, except in the case of covalent conjugates. We unexpectedly discovered several small...
Small molecules and antibodies are normally considered separately in drug discovery, except in the case of covalent conjugates. We unexpectedly discovered several small molecules that could inhibit or enhance antibody-epitope interactions which opens new possibilities in drug discovery and therapeutic modulation of auto-antibodies. We first discovered a small molecule, CRANAD-17, that enhanced the binding of an antibody to amyloid beta (Aβ), one of the major hallmarks of Alzheimer's disease, by stable triplex formation. Next, we found several small molecules that altered antibody-epitope interactions of tau and PD-L1 proteins, demonstrating the generality of this phenomenon. We report a new screening technology for ligand discovery, screening platform based on epitope alteration for drug discovery (SPEED), which is label-free for both the antibody and small molecule. SPEED, applied to an Aβ antibody, led to the discovery of a small molecule, GNF5837, that inhibits Aβ aggregation and another, obatoclax, that binds Aβ plaques and can serve as a fluorescent reporter in brain slices of AD mice. We also found a small molecule that altered the binding between Aβ and auto-antibodies from AD patient serum. SPEED reveals the sensitivity of antibody-epitope interactions to perturbation by small molecules and will have multiple applications in biotechnology and drug discovery.
PubMed: 35919434
DOI: 10.1039/d2sc02819k -
Oncotarget Jun 2016Poorly differentiated and anaplastic thyroid carcinomas are very aggressive, almost invariably lethal neoplasms for which no effective treatment exists. These tumors are...
Poorly differentiated and anaplastic thyroid carcinomas are very aggressive, almost invariably lethal neoplasms for which no effective treatment exists. These tumors are intrinsically resistant to cell death, even when their driver oncogenic signaling pathways are inhibited.We have undertaken a detailed analysis, in mouse and human thyroid cancer cells, of the mechanism through which Obatoclax, a pan-inhibitor of the anti-apoptotic proteins of the BCL2 family, effectively reduces tumor growth in vitro and in vivo.We demonstrate that Obatoclax does not induce apoptosis, but rather necrosis of thyroid cancer cells, and that non-transformed thyroid cells are significantly less affected by this compound. Surprisingly, we show that Obatoclax rapidly localizes to the lysosomes and induces loss of acidification, block of lysosomal fusion with autophagic vacuoles, and subsequent lysosomal permeabilization. Notably, prior lysosome neutralization using different V-ATPase inhibitors partially protects cancer cells from the toxic effects of Obatoclax. Although inhibition of autophagy does not affect Obatoclax-induced cell death, selective down-regulation of ATG7, but not of ATG5, partially impairs Obatoclax effects, suggesting the existence of autophagy-independent functions for ATG7. Strikingly, Obatoclax killing activity depends only on its accumulation in the lysosomes, and not on its interaction with BCL2 family members.Finally, we show that also other lysosome-targeting compounds, Mefloquine and LLOMe, readily induce necrosis in thyroid cancer cells, and that Mefloquine significantly impairs tumor growth in vivo, highlighting a clear vulnerability of these aggressive, apoptosis-resistant tumors that can be therapeutically exploited.
Topics: Animals; Antineoplastic Agents; Apoptosis; Autophagy-Related Protein 5; Autophagy-Related Protein 7; Cell Proliferation; Enzyme Inhibitors; Humans; Indoles; Lysosomes; Mefloquine; Mice; Mice, Knockout; Necrosis; Proto-Oncogene Proteins c-bcl-2; Pyrroles; RNA Interference; RNA, Small Interfering; Spheroids, Cellular; Thyroid Carcinoma, Anaplastic; Thyroid Neoplasms; Tumor Cells, Cultured
PubMed: 27144341
DOI: 10.18632/oncotarget.9121 -
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 -
Antimicrobial Agents and Chemotherapy Mar 2017As new pathogenic viruses continue to emerge, it is paramount to have intervention strategies that target a common denominator in these pathogens. The fusion of viral...
As new pathogenic viruses continue to emerge, it is paramount to have intervention strategies that target a common denominator in these pathogens. The fusion of viral and cellular membranes during viral entry is one such process that is used by many pathogenic viruses, including chikungunya virus, West Nile virus, and influenza virus. Obatoclax, a small-molecule antagonist of the Bcl-2 family of proteins, was previously determined to have activity against influenza A virus and also Sindbis virus. Here, we report it to be active against alphaviruses, like chikungunya virus (50% effective concentration [EC] = 0.03 μM) and Semliki Forest virus (SFV; EC = 0.11 μM). Obatoclax inhibited viral entry processes in an SFV temperature-sensitive mutant entry assay. A neutral red retention assay revealed that obatoclax induces the rapid neutralization of the acidic environment of endolysosomal vesicles and thereby most likely inhibits viral fusion. Characterization of escape mutants revealed that the L369I mutation in the SFV E1 fusion protein was sufficient to confer partial resistance against obatoclax. Other inhibitors that target the Bcl-2 family of antiapoptotic proteins inhibited neither viral entry nor endolysosomal acidification, suggesting that the antiviral mechanism of obatoclax does not depend on its anticancer targets. Obatoclax inhibited the growth of flaviviruses, like Zika virus, West Nile virus, and yellow fever virus, which require low pH for fusion, but not that of pH-independent picornaviruses, like coxsackievirus A9, echovirus 6, and echovirus 7. In conclusion, obatoclax is a novel inhibitor of endosomal acidification that prevents viral fusion and that could be pursued as a potential broad-spectrum antiviral candidate.
Topics: Animals; Antiviral Agents; Cell Line; Cell Membrane; Chikungunya virus; Cricetinae; Drug Resistance, Viral; Endosomes; Epithelial Cells; Gene Expression; Hepatocytes; Humans; Hydrogen-Ion Concentration; Indoles; Lysosomes; Membrane Fusion; Membrane Glycoproteins; Mutation; Neutral Red; Proto-Oncogene Proteins c-bcl-2; Pyrroles; Semliki forest virus; Viral Envelope Proteins; Virus Internalization; Virus Replication; West Nile virus; Yellow fever virus; Zika Virus
PubMed: 27993855
DOI: 10.1128/AAC.02227-16 -
ChemMedChem Aug 2022Multidrug resistant (MDR) bacteria are an increasing public health problem. One promising alternative to the development of new antibiotics is the use of antibiotic...
Multidrug resistant (MDR) bacteria are an increasing public health problem. One promising alternative to the development of new antibiotics is the use of antibiotic adjuvants, which would allow the continued use of FDA-approved antibiotics that have been rendered ineffective due to resistance. Herein, we report a series of dipyrrins and pyrrole derivatives designed as analogues of prodigiosin and obatoclax, several of which potentiate the activity of colistin against Klebsiella pneumoniae, with lead compounds also potentiating colistin against Acinetobacter baumannii and Pseudomonas aeruginosa.
Topics: Acinetobacter baumannii; Adjuvants, Pharmaceutic; Anti-Bacterial Agents; Colistin; Drug Resistance, Multiple, Bacterial; Microbial Sensitivity Tests; Prodigiosin; Pseudomonas aeruginosa
PubMed: 35704751
DOI: 10.1002/cmdc.202200286 -
International Journal of Molecular... Sep 2017Autophagy is an essential catabolic program that forms part of the stress response and enables cells to break down their own intracellular components within lysosomes... (Review)
Review
Autophagy is an essential catabolic program that forms part of the stress response and enables cells to break down their own intracellular components within lysosomes for recycling. Accumulating evidence suggests that autophagy plays vital roles in determining pathological outcomes of immune responses and tumorigenesis. Autophagy regulates innate and adaptive immunity affecting the pathologies of infectious, inflammatory, and autoimmune diseases. In cancer, autophagy appears to play distinct roles depending on the context of the malignancy by either promoting or suppressing key determinants of cancer cell survival. This review covers recent developments in the understanding of autophagy and discusses potential therapeutic interventions that may alter the outcomes of certain diseases.
Topics: Adaptive Immunity; Animals; Autoimmune Diseases; Autophagy; Benzylisoquinolines; Cholecalciferol; Humans; Immune System Diseases; Immunity, Innate; Indoles; Infections; Isoquinolines; Lysosomes; Maprotiline; Metformin; Neoplasms; Phenols; Pyrroles; Resveratrol; Sirolimus; Spermidine; Stilbenes; Tetrahydroisoquinolines; Trehalose
PubMed: 28895911
DOI: 10.3390/ijms18091959 -
Translational Cancer Research Jan 2023Hepatocellular carcinoma (HCC) is a common malignancy. Ferroptosis and cuproptosis promote HCC spread and proliferation. While fewer studies have combined ferroptosis...
Ferroptosis and cuproptosis prognostic signature for prediction of prognosis, immunotherapy and drug sensitivity in hepatocellular carcinoma: development and validation based on TCGA and ICGC databases.
BACKGROUND
Hepatocellular carcinoma (HCC) is a common malignancy. Ferroptosis and cuproptosis promote HCC spread and proliferation. While fewer studies have combined ferroptosis and cuproptosis to construct prognostic signature of HCC. This work attempts to establish a novel scoring system for predicting HCC prognosis, immunotherapy, and medication sensitivity based on ferroptosis-related genes (FRGs) and cuproptosis-related genes (CRGs).
METHODS
FerrDb and previous literature were used to identify FRGs. CRGs came from original research. The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) databases included the HCC transcriptional profile and clinical information [survival time, survival status, age, gender, Tumor Node Metastasis (TNM) stage, etc.]. Correlation, Cox, and least absolute shrinkage and selection operator (LASSO) regression analyses were used to narrow down prognostic genes and develop an HCC risk model. Using "caret", R separated TCGA-HCC samples into a training risk set and an internal test risk set. As external validation, we used ICGC samples. We employed Kaplan-Meier analysis and receiver operating characteristic (ROC) curve to evaluate the model's clinical efficacy. CIBERSORT and TIMER measured immunocytic infiltration in high- and low-risk populations.
RESULTS
[hazard ratio (HR) =1.477, P<0.001], (HR =1.373, P=0.001), (HR =1.650, P=0.004), (HR =1.576, P=0.002), (HR =1.728, P=0.008), (HR =1.826, P=0.002), (HR =1.596, P=0.005), (HR =1.290, P=0.002), and (HR =1.306, P<0.001) were distinguished to build predictive model. In both the model cohort (P<0.001) and the validation cohort (P<0.05), low-risk patients had superior overall survival (OS). The areas under the curve (AUCs) of the ROC curves in the training cohort (1-, 3-, and 5-year AUCs: 0.751, 0.727, and 0.743), internal validation cohort (1-, 3-, and 5-year AUCs: 0.826, 0.624, and 0.589), and ICGC cohort (1-, 3-, and 5-year AUCs: 0.699, 0.702, and 0.568) were calculated. Infiltration of immune cells and immunological checkpoints were also connected with our signature. Treatments with BI.2536, Epothilone.B, Gemcitabine, Mitomycin.C, Obatoclax. Mesylate, and Sunitinib may profit high-risk patients.
CONCLUSIONS
We analyzed FRGs and CRGs profiles in HCC and established a unique risk model for treatment and prognosis. Our data highlight FRGs and CRGs in clinical practice and suggest ferroptosis and cuproptosis may be therapeutic targets for HCC patients. To validate the model's clinical efficacy, more HCC cases and prospective clinical assessments are needed.
PubMed: 36760376
DOI: 10.21037/tcr-22-2203 -
Biomedicine & Pharmacotherapy =... Sep 2020Lung cancer still remains a leading cause of cancer mortality in the world. Obatoclax mesylate (OM), a B cell chronic lymphocytic leukemia/lymphoma 2 (Bcl-2) family...
Lung cancer still remains a leading cause of cancer mortality in the world. Obatoclax mesylate (OM), a B cell chronic lymphocytic leukemia/lymphoma 2 (Bcl-2) family antagonist, is a potential antitumor drug. However, its poor aqueous solubility restricts its clinical application. Although these inherent defects, nanotechnology can be used to improve the solubility and tumor target of OM, promoting its antitumor efficiency. In the present study, the poly(lactic-coglycolic acid) (PLGA) was used and combined with red blood-cell membrane (RBCm) to explore if OM-loaded RBCm nanoparticles could improve the antitumor efficacy of OM for the treatment of lung cancer with relatively lower side effects compared with the free OM. The good physicochemical stability of the prepared RBCm-OM/PLGA nanoparticles was confirmed, and the optimal size of 153 nm was screened out, along with sustained drug release behavior. We found that RBCm-OM/PLGA nanoparticles effectively reduced the proliferation of lung cancer cells. Additionally, RBCm-OM/PLGA nanoparticles considerably induced apoptosis in lung cancer cells by reducing Bcl-2 expression levels, accompanied with the improved Cyto-c releases in cytoplasm and Caspase-3 activation. Mitochondrial membrane potential was also obviously impaired in lung cancer cells incubated with RBCm-OM/PLGA nanoparticles. Compared with free OM, RBCm-OM/PLGA nanoparticles could greatly prolong the drug circulation time in vivo and upgraded the drug concentration accumulated in tumor tissue. Furthermore, RBCm-OM/PLGA nanoparticles exerted stronger antitumor efficacy in vivo against lung cancer progression with superior safety. Therefore, RBCm-OM/PLGA nanoparticles provided new potential for lung cancer therapy with the improved safety and therapeutic effect.
Topics: A549 Cells; Animals; Antineoplastic Agents; Apoptosis; Biomimetics; Carcinoma, Non-Small-Cell Lung; Cell Proliferation; Delayed-Action Preparations; Drug Compounding; Drug Liberation; Drug Stability; Humans; Indoles; Lung Neoplasms; Male; Mice, Inbred C57BL; Nanoparticles; Polylactic Acid-Polyglycolic Acid Copolymer; Proto-Oncogene Proteins c-bcl-2; Pyrroles; Signal Transduction; Solubility; Xenograft Model Antitumor Assays
PubMed: 32563984
DOI: 10.1016/j.biopha.2020.110371 -
Oncotarget Sep 2017We have previously reported overexpression of antiapoptotic MCL-1 protein in human oral cancers and its association with therapy resistance and poor prognosis, implying...
We have previously reported overexpression of antiapoptotic MCL-1 protein in human oral cancers and its association with therapy resistance and poor prognosis, implying it to be a potential therapeutic target. Hence, we investigated the efficacy and mechanism of action of Obatoclax, a BH3 mimetic pan BCL-2 inhibitor in human oral cancer cell lines. All cell lines exhibited high sensitivity to Obatoclax with complete clonogenic inhibition at 200-400 nM concentration which correlated with their MCL-1 expression. Mechanistic insights revealed that Obatoclax induced a caspase-independent cell death primarily by induction of a defective autophagy. Suppression of autophagy by ATG5 downregulation significantly blocked Obatoclax-induced cell death. Further, Obatoclax induced interaction of p62 with key components of the necrosome RIP1K and RIP3K. Necrostatin-1 mediated inhibition of RIP1K significantly protected the cells from Obatoclax induced cell death. Moreover, Obatoclax caused extensive mitochondrial stress leading to their dysfunction. Interestingly, MCL-1 downregulation alone caused mitochondrial stress, highlighting its importance for mitochondrial homeostasis. We also demonstrated efficacy of Obatoclax against oral cancer xenografts and its synergism with ionizing radiation . Our studies thus suggest that Obatoclax induces autophagy-dependent necroptosis in oral cancer cells and holds a great promise in the improved management of oral cancer patients.
PubMed: 28947954
DOI: 10.18632/oncotarget.11085