-
BioMed Research International 2019B-cell lymphoma 2 (Bcl-2) is a regulator protein involved in apoptosis. In the past few decades, this protein has been demonstrated to have high efficacy in cancer... (Review)
Review
B-cell lymphoma 2 (Bcl-2) is a regulator protein involved in apoptosis. In the past few decades, this protein has been demonstrated to have high efficacy in cancer therapy, and several approaches targeting Bcl-2 have been tested clinically (e.g., oblimersen, ABT-737, ABT-263, obatoclax mesylate, and AT-101). This review reports potential Bcl-2 inhibitors according to current information on their underlying mechanism and the results of clinical trials. In addition, the function and mechanisms of other potentially valuable Bcl-2 inhibitors that did not show efficacy in clinical studies are also discussed. This summary of the development of Bcl-2 inhibitors provides worthwhile viewpoints on the use of biomedical approaches in future cancer therapy.
Topics: Aniline Compounds; Antineoplastic Agents; Apoptosis; Biphenyl Compounds; Cell Line, Tumor; Gossypol; Humans; Lymphoma, B-Cell; Nitrophenols; Piperazines; Proto-Oncogene Proteins c-bcl-2; Sulfonamides; Thionucleotides
PubMed: 31662966
DOI: 10.1155/2019/1212369 -
The Journal of Biological Chemistry Oct 2012Influenza A viruses (IAVs) infect humans and cause significant morbidity and mortality. Different treatment options have been developed; however, these were insufficient...
Influenza A viruses (IAVs) infect humans and cause significant morbidity and mortality. Different treatment options have been developed; however, these were insufficient during recent IAV outbreaks. Here, we conducted a targeted chemical screen in human nonmalignant cells to validate known and search for novel host-directed antivirals. The screen validated saliphenylhalamide (SaliPhe) and identified two novel anti-IAV agents, obatoclax and gemcitabine. Further experiments demonstrated that Mcl-1 (target of obatoclax) provides a novel host target for IAV treatment. Moreover, we showed that obatoclax and SaliPhe inhibited IAV uptake and gemcitabine suppressed viral RNA transcription and replication. These compounds possess broad spectrum antiviral activity, although their antiviral efficacies were virus-, cell type-, and species-specific. Altogether, our results suggest that phase II obatoclax, investigational SaliPhe, and FDA/EMEA-approved gemcitabine represent potent antiviral agents.
Topics: Amides; Animals; Antiviral Agents; Chlorocebus aethiops; Deoxycytidine; Dogs; Humans; Indoles; Influenza A Virus, H3N2 Subtype; Influenza, Human; Myeloid Cell Leukemia Sequence 1 Protein; Proto-Oncogene Proteins c-bcl-2; Pyrroles; RNA, Viral; Salicylates; Vero Cells; Virus Replication; Gemcitabine
PubMed: 22910914
DOI: 10.1074/jbc.M112.392142 -
PloS One 2014Despite the fact that new treatment regimes have improved overall survival of patients challenged by colorectal cancer (CRC), prognosis in the metastatic situation is...
Despite the fact that new treatment regimes have improved overall survival of patients challenged by colorectal cancer (CRC), prognosis in the metastatic situation is still restricted. The Bcl-2 family of proteins has been identified as promising anti cancer drug target. Even though small molecules targeting Bcl-2 proteins are in clinical trials, little is known regarding their effects on CRC. The aim of this study was to preclinically investigate the value of ABT-737 and Obatoclax as anticancer drugs for CRC treatment. The effects of the BH3-mimetics ABT-737 and Obatoclax on CRC cells were assessed using viability and apoptosis assays. Wound healing migration and boyden chamber invasion assays were applied. 3-dimensional cell cultures were used for long term assessment of invasion and proliferation. Clinically relevant concentrations of pan-Bcl-2 inhibitor Obatoclax did not induce cell death. In contrast, the BH3-mimetic ABT-737 induced apoptosis in a dose dependent manner. Obatoclax caused a cell line specific slowdown of CRC cell growth. Furthermore, Obatoclax, but not ABT-737, recovered E-Cadherin expression and led to impaired migration and invasion of CRC cells. The proliferative capacity and invasiveness of CRC cells was strikingly inhibited by low dose Obatoclax in long term 3-dimensional cell cultures. Obatoclax, but not ABT-737, caused a G1-phase arrest accompanied by a downregulation of Cyclin D1 and upregulation of p27 and p21. Overexpression of Mcl-1, Bcl-xL or Bcl-2 reversed the inhibitory effect of Obatoclax on migration but failed to restore the proliferative capacity of Obatoclax-treated CRC cells. The data presented indicate broad and multifaceted antitumor effects of the pan-Bcl-2 inhibitor Obatoclax on CRC cells. In contrast to ABT-737, Obatoclax inhibited migration, invasion and proliferation in sublethal doses. In summary, this study recommends pan-Bcl-2 inhibition as a promising approach for clinical trials in CRC.
Topics: Antineoplastic Agents; Apoptosis; Biphenyl Compounds; Cadherins; Cell Cycle; Cell Line, Tumor; Cell Movement; Cell Proliferation; Colorectal Neoplasms; Cyclin D1; Cyclin-Dependent Kinase Inhibitor p21; Cyclin-Dependent Kinase Inhibitor p27; G1 Phase Cell Cycle Checkpoints; Gene Expression; Humans; Indoles; Nitrophenols; Piperazines; Proto-Oncogene Proteins c-bcl-2; Pyrroles; Sulfonamides
PubMed: 25192188
DOI: 10.1371/journal.pone.0106571 -
Molecular Pharmacology Dec 2012Previous studies showed that lapatinib and obatoclax interact in a greater-than-additive fashion to cause cell death and do so through a toxic form of autophagy. The...
Previous studies showed that lapatinib and obatoclax interact in a greater-than-additive fashion to cause cell death and do so through a toxic form of autophagy. The present studies sought to extend our analyses. Lapatinib and obatoclax killed multiple tumor cell types, and cells lacking phosphatase and tensin homolog (PTEN) function were relatively resistant to drug combination lethality; expression of PTEN in PTEN-null breast cancer cells restored drug sensitivity. Coadministration of lapatinib with obatoclax elicited autophagic cell death that was attributable to the actions of mitochondrial reactive oxygen species. Wild-type cells but not mitochondria-deficient rho-zero cells were radiosensitized by lapatinib and obatoclax treatment. Activation of p38 mitogen-activated protein kinase (MAPK) and c-Jun NH(2)-terminal kinase 1/2 (JNK1/2) by the drug combination was enhanced by radiation, and signaling by p38 MAPK and JNK1/2 promoted cell killing. In immunohistochemical analyses, the autophagosome protein p62 was determined to be associated with protein kinase-like endoplasmic reticulum kinase (PERK) and inositol-requiring enzyme 1, as well as with binding immunoglobulin protein/78-kDa glucose-regulated protein, in drug combination-treated cells. Knockdown of PERK suppressed drug-induced autophagy and protected tumor cells from the drug combination. Knockdown of PERK suppressed the reduction in Mcl-1 expression after drug combination exposure, and overexpression of Mcl-1 protected cells. Our data indicate that mitochondrial function plays an essential role in cell killing by lapatinib and obatoclax, as well as radiosensitization by this drug combination.
Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Autophagy; Breast Neoplasms; Cell Line, Tumor; Endoplasmic Reticulum Stress; Female; HSP70 Heat-Shock Proteins; Humans; Indoles; Lapatinib; Membrane Proteins; Mice; Mice, Nude; Mitochondria; Mitogen-Activated Protein Kinase 8; Mitogen-Activated Protein Kinase 9; Pyrroles; Quinazolines; Reactive Oxygen Species; eIF-2 Kinase; p38 Mitogen-Activated Protein Kinases
PubMed: 22989520
DOI: 10.1124/mol.112.081539 -
Viruses Oct 2019Viruses are the major causes of acute and chronic infectious diseases in the world. According to the World Health Organization, there is an urgent need for better...
Viruses are the major causes of acute and chronic infectious diseases in the world. According to the World Health Organization, there is an urgent need for better control of viral diseases. Repurposing existing antiviral agents from one viral disease to another could play a pivotal role in this process. Here, we identified novel activities of obatoclax and emetine against herpes simplex virus type 2 (HSV-2), echovirus 1 (EV1), human metapneumovirus (HMPV) and Rift Valley fever virus (RVFV) in cell cultures. Moreover, we demonstrated novel activities of emetine against influenza A virus (FLUAV), niclosamide against HSV-2, brequinar against human immunodeficiency virus 1 (HIV-1), and homoharringtonine against EV1. Our findings may expand the spectrum of indications of these safe-in-man agents and reinforce the arsenal of available antiviral therapeutics pending the results of further in vitro and in vivo tests.
Topics: Animals; Antiviral Agents; Biphenyl Compounds; Cell Culture Techniques; Chlorocebus aethiops; Dogs; Emetine; Enterovirus B, Human; HIV-1; Herpesvirus 2, Human; Homoharringtonine; Humans; Indoles; Madin Darby Canine Kidney Cells; Niclosamide; Pyrroles; Vero Cells; Virus Diseases; Viruses
PubMed: 31635418
DOI: 10.3390/v11100964 -
Cell Death & Disease Dec 2010Direct pharmacological targeting of the anti-apoptotic B-cell lymphoma-2 (BCL-2) family is an attractive therapeutic strategy for treating cancer. Obatoclax is a...
Direct pharmacological targeting of the anti-apoptotic B-cell lymphoma-2 (BCL-2) family is an attractive therapeutic strategy for treating cancer. Obatoclax is a pan-BCL-2 family inhibitor currently in clinical development. Here we show that, although obatoclax can induce mitochondrial apoptosis dependent on BCL-2 associated x protein/BCL-2 antagonist killer (BAX/BAK) consistent with its on-target pharmacodynamics, simultaneous silencing of both BAX and BAK did not abolish acute toxicity or loss of clonogenicity. This is despite complete inhibition of apoptosis. Obatoclax dramatically reduced viability without inducing loss of plasma membrane integrity. This was associated with rapid processing of light chain-3 (LC3) and reduction of S6 kinase phosphorylation, consistent with autophagy. Dramatic ultrastructural vacuolation, not typical of autophagy, was also induced. Silencing of beclin-1 failed to prevent LC3 processing, whereas knockout of autophagy-related (Atg)7 abolished LC3 processing but failed to prevent obatoclax-induced loss of clonogenicity or ultrastructural changes. siRNA silencing of Atg7 in BAX/BAK knockout mouse embryonic fibroblasts did not prevent obatoclax-induced loss of viability. Cells selected for obatoclax resistance evaded apoptosis independent of changes in BCL-2 family expression and displayed reduced LC3 processing. In summary, obatoclax exhibits BAX- and BAK-dependent and -independent mechanisms of toxicity and activation of autophagy. Mechanisms other than autophagy and apoptosis are blocked in obatoclax resistant cells and contribute significantly to obatoclax's anticancer efficacy.
Topics: Animals; Apoptosis; Apoptosis Regulatory Proteins; Autophagy; Autophagy-Related Protein 7; Beclin-1; Cell Line, Tumor; Cell Membrane; Drug Resistance, Neoplasm; Humans; Indoles; Membrane Proteins; Mice; Myeloid Cell Leukemia Sequence 1 Protein; Proto-Oncogene Proteins c-bcl-2; Pyrroles; Ubiquitin-Activating Enzymes; bcl-2 Homologous Antagonist-Killer Protein; bcl-2-Associated X Protein
PubMed: 21368880
DOI: 10.1038/cddis.2010.86 -
Cell Death & Disease Apr 2022Atypical teratoid/rhabdoid tumors (AT/RT) are the most common malignant brain tumors of infancy and have a dismal 4-year event-free survival (EFS) of 37%. We have...
Atypical teratoid/rhabdoid tumors (AT/RT) are the most common malignant brain tumors of infancy and have a dismal 4-year event-free survival (EFS) of 37%. We have previously shown that mTOR activation contributes to AT/RT's aggressive growth and poor survival. Targeting the mTOR pathway with the dual mTORC1/2 inhibitor TAK-228 slows tumor growth and extends survival in mice bearing orthotopic xenografts. However, responses are primarily cytostatic with limited durability. The aim of this study is to understand the impact of mTOR inhibitors on AT/RT signaling pathways and design a rational combination therapy to drive a more durable response to this promising therapy. We performed RNASeq, gene expression studies, and protein analyses to identify pathways disrupted by TAK-228. We find that TAK-228 decreases the expression of the transcription factor NRF2 and compromises AT/RT cellular defenses against oxidative stress and apoptosis. The BH3 mimetic, Obatoclax, is a potent inducer of oxidative stress and apoptosis in AT/RT. These complementary mechanisms of action drive extensive synergies between TAK-228 and Obatoclax slowing AT/RT cell growth and inducing apoptosis and cell death. Combination therapy activates the integrative stress response as determined by increased expression of phosphorylated EIF2α, ATF4, and CHOP, and disrupts the protective NOXA.MCL-1.BIM axis, forcing stressed cells to undergo apoptosis. Combination therapy is well tolerated in mice bearing orthotopic xenografts of AT/RT, slows tumor growth, and extends median overall survival. This novel combination therapy could be added to standard upfront therapies or used as a salvage therapy for relapsed disease to improve outcomes in AT/RT.
Topics: Animals; Humans; Indoles; Mechanistic Target of Rapamycin Complex 1; Mice; Pyrroles; Rhabdoid Tumor; TOR Serine-Threonine Kinases
PubMed: 35484114
DOI: 10.1038/s41419-022-04868-9 -
Oncotarget Mar 2016Obatoclax, a pan-inhibitor of anti-apoptotic Bcl-2 proteins, exhibits cytotoxic effect on cancer cells through both apoptosis-dependent and -independent pathways. Here...
Obatoclax, a pan-inhibitor of anti-apoptotic Bcl-2 proteins, exhibits cytotoxic effect on cancer cells through both apoptosis-dependent and -independent pathways. Here we show that obatoclax caused cytotoxicity in both cisplatin-sensitive and -resistant esophageal cancer cells. Although obatoclax showed differential apoptogenic effects in these cells, it consistently blocked autophagic flux, which was evidenced by concomitant accumulation of LC3-II and p62. Obatoclax was trapped in lysosomes and induced lysosome clustering. Obatoclax also substantially reduced the expression of lysosomal cathepsins B, D and L. Moreover, cathepsin knockdown was sufficient to induce cytotoxicity, connecting lysosomal function to cell viability. Consistent with the known function of autophagy, obatoclax caused the accumulation of polyubiquitinated proteins and showed synergy with proteasome inhibition. Taken together, our studies unveiled impaired lysosomal function as a novel mechanism whereby obatoclax mediates its cytotoxic effect in esophageal cancer cells.
Topics: Antineoplastic Agents; Apoptosis; Apoptosis Regulatory Proteins; Autophagy; Cathepsin B; Cell Proliferation; Cisplatin; Drug Resistance, Neoplasm; Enzyme Inhibitors; Esophageal Neoplasms; Humans; Indoles; Lysosomes; Pyrroles; Tumor Cells, Cultured
PubMed: 26910910
DOI: 10.18632/oncotarget.7492 -
Viruses Sep 2020Zika virus (ZIKV) was identified in 1947 in the Zika forest of Uganda and it has emerged recently as a global health threat, with recurring outbreaks and its...
Zika virus (ZIKV) was identified in 1947 in the Zika forest of Uganda and it has emerged recently as a global health threat, with recurring outbreaks and its associations with congenital microcephaly through maternal fetal transmission and Guillain-Barré syndrome. Currently, there are no United States (US) Food and Drug Administration (FDA)-approved vaccines or antivirals to treat ZIKV infections, which underscores an urgent medical need for the development of disease intervention strategies to treat ZIKV infection and associated disease. Drug repurposing offers various advantages over developing an entirely new drug by significantly reducing the timeline and resources required to advance a candidate antiviral into the clinic. Screening the ReFRAME library, we identified ten compounds with antiviral activity against the prototypic mammarenavirus lymphocytic choriomeningitis virus (LCMV). Moreover, we showed the ability of these ten compounds to inhibit influenza A and B virus infections, supporting their broad-spectrum antiviral activity. In this study, we further evaluated the broad-spectrum antiviral activity of the ten identified compounds by testing their activity against ZIKV. Among the ten compounds, Azaribine (SI-MTT = 146.29), AVN-944 (SI-MTT = 278.16), and Brequinar (SI-MTT = 157.42) showed potent anti-ZIKV activity in post-treatment therapeutic conditions. We also observed potent anti-ZIKV activity for Mycophenolate mofetil (SI-MTT = 20.51), Mycophenolic acid (SI-MTT = 36.33), and AVN-944 (SI-MTT = 24.51) in pre-treatment prophylactic conditions and potent co-treatment inhibitory activity for Obatoclax (SI-MTT = 60.58), Azaribine (SI-MTT = 91.51), and Mycophenolate mofetil (SI-MTT = 73.26) in co-treatment conditions. Importantly, the inhibitory effect of these compounds was strain independent, as they similarly inhibited ZIKV strains from both African and Asian/American lineages. Our results support the broad-spectrum antiviral activity of these ten compounds and suggest their use for the development of antiviral treatment options of ZIKV infection.
Topics: A549 Cells; Animals; Antiviral Agents; Apoptosis; Azauridine; Biphenyl Compounds; Carbamates; Cell Survival; Chlorocebus aethiops; Drug Repositioning; Guillain-Barre Syndrome; Humans; Microcephaly; Phenylurea Compounds; Uganda; Vero Cells; Virus Replication; Zika Virus; Zika Virus Infection
PubMed: 32961956
DOI: 10.3390/v12091041 -
Advances in Medicine 2014Due to their central role in the regulation of apoptosis, the antiapoptotic BCL2-proteins are highly promising targets for the development of novel anticancer... (Review)
Review
Due to their central role in the regulation of apoptosis, the antiapoptotic BCL2-proteins are highly promising targets for the development of novel anticancer treatments. To this end, several strategies have been developed to inhibit BCL2, BCL-XL, BCL-w, and MCL1. While early clinical trials in haematological malignancies demonstrated exciting single-agent activity of BCL2-inhibitors, the response in solid tumours was limited, indicating that, in solid tumours, different strategies have to be developed in order to successfully treat patients with BCL2-inhibitors. In this review, the function of the different antiapoptotic BCL2-proteins and their role in solid tumours will be discussed. In addition, a comprehensive analysis of current small molecules targeting these antiapoptotic BCL2-proteins (e.g., ABT-737, ABT-263, ABT-199, TW-37, sabutoclax, obatoclax, and MIM1) will be provided including a discussion of the results of any clinical trials. This analysis will summarise the potential of BCL2-inhibitors for the treatment of solid tumours and will unravel novel approaches to utilise these inhibitors in clinical applications.
PubMed: 26556430
DOI: 10.1155/2014/943648