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Lin X, Dong L, Miao Q, Huang Z, Wang F. Cycloheptylprodigiosin from marine bacterium Spartinivicinus ruber MCCC 1K03745 T induces a novel form of cell death characterized by Golgi disruption and enhanced secretion of cathepsin D in non-small cell lung cancer cell lines. Eur J Pharmacol 2024; 974:176608. [PMID: 38663542 DOI: 10.1016/j.ejphar.2024.176608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 04/15/2024] [Accepted: 04/22/2024] [Indexed: 05/03/2024]
Abstract
Prodiginines have been studied extensively for their anticancer activity, however, the majority of the research has focused on prodigiosin. In this study, cycloheptylprodigiosin (S-1) is extracted from marine bacterium Spartinivicinus ruber MCCC 1K03745T, and its anticancer property was investigated. It exhibits remarkable cytotoxicity against a panel of human lung cancer cell lines, with the IC50 values ranging from 84.89 nM to 661.2 nM. After 6 h of treatment, S-1 gradually accumulates on mitochondria and lysosomes. While lower doses of S-1 induce cell cycle arrest, treatment with higher doses results in cell death in apoptotic independent manner in both NCI-H1299 and NCI-H460 cell lines. Interestingly, treatment with S-1 leads to the accumulation of LC3B-II via pathways that vary among different cell lines. In addition to its role as an autophagy inhibitor, S-1 also promotes autophagy initiation as demonstrated by the increment of EGFP fragment in the EGFP-LC3 degradation assay, however, inhibition of autophagy does not rescue cells from death induced by S-1. Mechanistically, S-1 impairs autophagic flux through disrupting acidic lysosomal pH and blocking the maturation of cathepsin D. Moreover, treatment with S-1 enhanced secretion of both pro- and mature forms of cathepsin D, coincident with disintegration of trans-Golgi network. Interestingly, S-1 does not induce ferroptosis, pyroptosis or necroptosis in NCI-H1299 cells. However, treatment of NCI-H460 cells with S-1 induces methuosis, which can be suppressed by Rac1 inhibitor EHT 1864. Our data demonstrate that S-1 is an effective anticancer agent with potential therapeutic application.
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Affiliation(s)
- Xiaosi Lin
- Fujian Province Key Laboratory for the Development of Bioactive Material from Marine Algae, Quanzhou Normal University, Quanzhou, 362000, China; College of Oceanology and Food Science, Quanzhou Normal University, Quanzhou, 362000, China.
| | - Le Dong
- Fujian Province Key Laboratory for the Development of Bioactive Material from Marine Algae, Quanzhou Normal University, Quanzhou, 362000, China; College of Oceanology and Food Science, Quanzhou Normal University, Quanzhou, 362000, China
| | - Qing Miao
- College of Oceanology and Food Science, Quanzhou Normal University, Quanzhou, 362000, China
| | - Zhaobin Huang
- Fujian Province Key Laboratory for the Development of Bioactive Material from Marine Algae, Quanzhou Normal University, Quanzhou, 362000, China; College of Oceanology and Food Science, Quanzhou Normal University, Quanzhou, 362000, China
| | - Fang Wang
- Fujian Province Key Laboratory for the Development of Bioactive Material from Marine Algae, Quanzhou Normal University, Quanzhou, 362000, China; College of Oceanology and Food Science, Quanzhou Normal University, Quanzhou, 362000, China
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2
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Wu Q, Sharma D. Autophagy and Breast Cancer: Connected in Growth, Progression, and Therapy. Cells 2023; 12:cells12081156. [PMID: 37190065 DOI: 10.3390/cells12081156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 03/29/2023] [Accepted: 04/05/2023] [Indexed: 05/17/2023] Open
Abstract
Despite an increase in the incidence of breast cancer worldwide, overall prognosis has been consistently improving owing to the development of multiple targeted therapies and novel combination regimens including endocrine therapies, aromatase inhibitors, Her2-targeted therapies, and cdk4/6 inhibitors. Immunotherapy is also being actively examined for some breast cancer subtypes. This overall positive outlook is marred by the development of resistance or reduced efficacy of the drug combinations, but the underlying mechanisms are somewhat unclear. It is interesting to note that cancer cells quickly adapt and evade most therapies by activating autophagy, a catabolic process designed to recycle damaged cellular components and provide energy. In this review, we discuss the role of autophagy and autophagy-associated proteins in breast cancer growth, drug sensitivity, tumor dormancy, stemness, and recurrence. We further explore how autophagy intersects and reduces the efficacy of endocrine therapies, targeted therapies, radiotherapy, chemotherapies as well as immunotherapy via modulating various intermediate proteins, miRs, and lncRNAs. Lastly, the potential application of autophagy inhibitors and bioactive molecules to improve the anticancer effects of drugs by circumventing the cytoprotective autophagy is discussed.
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Affiliation(s)
- Qitong Wu
- Department of Oncology, Johns Hopkins University School of Medicine and the Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, MD 21287-0013, USA
| | - Dipali Sharma
- Department of Oncology, Johns Hopkins University School of Medicine and the Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, MD 21287-0013, USA
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3
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Li Y, Zhu Y, Han J, Fang J, Xiu Z, Li S, Li W, Yang X, Jin N, Sun L, Li X, Li Y. Ad-Apoptin-hTERTp-E1a Regulates Autophagy Through the AMPK-mTOR-eIF4F Signaling Axis to Reduce Drug Resistance of MCF-7/ADR Cells. Front Mol Biosci 2021; 8:763500. [PMID: 34869595 PMCID: PMC8640141 DOI: 10.3389/fmolb.2021.763500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 11/03/2021] [Indexed: 11/13/2022] Open
Abstract
Ad-VT (Ad-Apoptin-hTERTp-E1a) is a type of oncolytic adenovirus with dual specific tumor cell death ability. It can effectively induce cell death of breast cancer cells and has better effect when used in combination with chemotherapy drugs. However, it has not been reported whether Ad-VT reduces the resistance of breast cancer cells to chemotherapy drugs. The purpose of this study is to investigate the effect of Ad-VT on drug resistance of Adriamycin-resistant breast cancer cells. For this, the effects of different doses of Ad-VT on the resistance of breast cancer cells to Adriamycin were analyzed using qualitative and quantitative experiments in vitro and in vivo. The Ad-VT can reduce the resistance of MCF-7/ADR to adriamycin, which is caused by the reduction of MRP1 protein level in MCF-7/ADR cells after treatment with Ad-VT, and MRP1 can be interfered with by autophagy inhibitors. Subsequently, the upstream signal of autophagy was analyzed and it was found that Ad-VT reduced the resistance of cells to doxorubicin by reducing the level of mTOR, and then the analysis of the upstream and downstream proteins of mTOR found that Ad-VT increased the sensitivity of MCF-7/ADR cells to adriamycin by activating AMPK-mTOR-eIF4F signaling axis. Ad-VT can not only significantly induce cell death in MCF-7/ADR cells, but also improved their sensitivity to Adriamycin. Therefore, the combination of Ad-VT and chemotherapy drugs may become a new strategy for the treatment of breast cancer in overcoming Adriamycin resistance.
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Affiliation(s)
- Yaru Li
- Academician Workstation of Jilin Province, Changchun University of Chinese Medicine, Changchun, China.,Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, China.,Medical College, Yanbian University, Yanji, China
| | - Yilong Zhu
- Academician Workstation of Jilin Province, Changchun University of Chinese Medicine, Changchun, China
| | - Jicheng Han
- Academician Workstation of Jilin Province, Changchun University of Chinese Medicine, Changchun, China
| | - Jinbo Fang
- Academician Workstation of Jilin Province, Changchun University of Chinese Medicine, Changchun, China
| | - Zhiru Xiu
- Academician Workstation of Jilin Province, Changchun University of Chinese Medicine, Changchun, China
| | - Shanzhi Li
- Academician Workstation of Jilin Province, Changchun University of Chinese Medicine, Changchun, China
| | - Wenjie Li
- Institute of Virology, Wenzhou University, Wenzhou, China
| | - Xia Yang
- Academician Workstation of Jilin Province, Changchun University of Chinese Medicine, Changchun, China.,Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, China.,Medical College, Yanbian University, Yanji, China
| | - Ningyi Jin
- Academician Workstation of Jilin Province, Changchun University of Chinese Medicine, Changchun, China.,Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
| | - Lili Sun
- Medical College, Yanbian University, Yanji, China.,Department of Head and Neck Surgery, Tumor Hospital of Jilin Province, Changchun, China
| | - Xiao Li
- Academician Workstation of Jilin Province, Changchun University of Chinese Medicine, Changchun, China.,Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
| | - Yiquan Li
- Academician Workstation of Jilin Province, Changchun University of Chinese Medicine, Changchun, China.,Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, China.,Medical College, Yanbian University, Yanji, China
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4
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Wen N, Lv Q, Du ZG. MicroRNAs involved in drug resistance of breast cancer by regulating autophagy. J Zhejiang Univ Sci B 2021; 21:690-702. [PMID: 32893526 DOI: 10.1631/jzus.b2000076] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Autophagy is a conserved catabolic process characterized by degradation and recycling of cytosolic components or organelles through a lysosome-dependent pathway. It has a complex and close relationship to drug resistance in breast cancer. MicroRNAs (miRNAs) are small noncoding molecules that can influence numerous cellular processes including autophagy, through the posttranscriptional regulation of gene expression. Autophagy is regulated by many proteins and pathways, some of which in turn have been found to be regulated by miRNAs. These miRNAs may affect the drug resistance of breast cancer. Drug resistance is the main cause of distant recurrence, metastasis and death in breast cancer patients. In this review, we summarize the causative relationship between autophagy and drug resistance of breast cancer. The roles of autophagy-related proteins and pathways and their associated miRNAs in drug resistance of breast cancer are also discussed.
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Affiliation(s)
- Nan Wen
- Department of Breast Surgery, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Qing Lv
- Department of Breast Surgery, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Zheng-Gui Du
- Department of Breast Surgery, West China Hospital, Sichuan University, Chengdu 610041, China
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5
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Nagy MI, Darwish KM, Kishk SM, Tantawy MA, Nasr AM, Qushawy M, Swidan SA, Mostafa SM, Salama I. Design, Synthesis, Anticancer Activity, and Solid Lipid Nanoparticle Formulation of Indole- and Benzimidazole-Based Compounds as Pro-Apoptotic Agents Targeting Bcl-2 Protein. Pharmaceuticals (Basel) 2021; 14:ph14020113. [PMID: 33535550 PMCID: PMC7912796 DOI: 10.3390/ph14020113] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2020] [Revised: 01/20/2021] [Accepted: 01/26/2021] [Indexed: 02/01/2023] Open
Abstract
Cancer is a multifactorial disease necessitating identification of novel targets for its treatment. Inhibition of Bcl-2 for triggered pro-apoptotic signaling is considered a promising strategy for cancer treatment. Within the current work, we aimed to design and synthesize a new series of benzimidazole- and indole-based derivatives as inhibitors of Bcl-2 protein. The market pan-Bcl-2 inhibitor, obatoclax, was the lead framework compound for adopted structural modifications. The obatoclax’s pyrrolylmethine linker was replaced with straight alkylamine or carboxyhydrazine methylene linkers providing the new compounds. This strategy permitted improved structural flexibility of synthesized compounds adopting favored maneuvers for better fitting at the Bcl-2 major hydrophobic pocket. Anti-cancer activity of the synthesized compounds was further investigated through MTT-cytotoxic assay, cell cycle analysis, RT-PCR, ELISA and DNA fragmentation. Cytotoxic results showed compounds 8a, 8b and 8c with promising cytotoxicity against MDA-MB-231/breast cancer cells (IC50 = 12.69 ± 0.84 to 12.83 ± 3.50 µM), while 8a and 8c depicted noticeable activities against A549/lung adenocarcinoma cells (IC50 = 23.05 ± 1.45 and 11.63 ± 2.57 µM, respectively). The signaling Bcl-2 inhibition pathway was confirmed by molecular docking where significant docking energies and interactions with key Bcl-2 pocket residues were depicted. Moreover, the top active compound, 8b, showed significant upregulated expression levels of pro-apoptotic/anti-apoptotic of genes; Bax, Bcl-2, caspase-3, -8, and -9 through RT-PCR assay. Improving the compound’s pharmaceutical profile was undertaken by introducing 8b within drug-solid/lipid nanoparticle formulation prepared by hot melting homogenization technique and evaluated for encapsulation efficiency, particle size, and zeta potential. Significant improvement was seen at the compound’s cytotoxic activity. In conclusion, 8b is introduced as a promising anti-cancer lead candidate that worth future fine-tuned lead optimization and development studies while exploring its potentiality through in-vivo preclinical investigation.
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Affiliation(s)
- Manar I. Nagy
- Department of Medicinal Chemistry, Faculty of Pharmacy, Suez Canal University, Ismailia 41522, Egypt; (M.I.N.); (K.M.D.); (S.M.K.); (S.M.M.)
| | - Khaled M. Darwish
- Department of Medicinal Chemistry, Faculty of Pharmacy, Suez Canal University, Ismailia 41522, Egypt; (M.I.N.); (K.M.D.); (S.M.K.); (S.M.M.)
| | - Safaa M. Kishk
- Department of Medicinal Chemistry, Faculty of Pharmacy, Suez Canal University, Ismailia 41522, Egypt; (M.I.N.); (K.M.D.); (S.M.K.); (S.M.M.)
| | - Mohamed A. Tantawy
- National Research Center, Hormones Department, Medical Research Division, Dokki, Giza 12622, Egypt;
| | - Ali M. Nasr
- Department of Pharmaceutics, Faculty of Pharmacy, Port Said University, Port Said 42526, Egypt;
- Department of Pharmaceutics, Faculty of Pharmacy, Sinai University, Alarish, North Sinai 45511, Egypt;
| | - Mona Qushawy
- Department of Pharmaceutics, Faculty of Pharmacy, Sinai University, Alarish, North Sinai 45511, Egypt;
- Department of Pharmaceutics, Faculty of Pharmacy, University of Tabuk, Tabuk 71491, Saudi Arabia
| | - Shady A. Swidan
- Department of Pharmaceutics, Faculty of Pharmacy, The British University in Egypt, El-Sherouk City, Cairo 11837, Egypt;
- The Center for Drug Research and Development (CDRD), Faculty of Pharmacy, The British University in Egypt, El-Sherouk City, Cairo 11837, Egypt
| | - Samia M. Mostafa
- Department of Medicinal Chemistry, Faculty of Pharmacy, Suez Canal University, Ismailia 41522, Egypt; (M.I.N.); (K.M.D.); (S.M.K.); (S.M.M.)
| | - Ismail Salama
- Department of Medicinal Chemistry, Faculty of Pharmacy, Suez Canal University, Ismailia 41522, Egypt; (M.I.N.); (K.M.D.); (S.M.K.); (S.M.M.)
- Correspondence: ; Tel.: +20-102-225-7643
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6
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Obatoclax, a Pan-BCL-2 Inhibitor, Downregulates Survivin to Induce Apoptosis in Human Colorectal Carcinoma Cells Via Suppressing WNT/β-catenin Signaling. Int J Mol Sci 2020; 21:ijms21051773. [PMID: 32150830 PMCID: PMC7084590 DOI: 10.3390/ijms21051773] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 02/27/2020] [Accepted: 03/03/2020] [Indexed: 12/15/2022] Open
Abstract
Colorectal cancer (CRC) is a highly prevailing cancer and the fourth leading cause of cancer mortality worldwide. Aberrant expression of antiapoptotic BCL-2 family proteins is closely linked to neoplastic progression and chemoresistance. Obatoclax is a clinically developed drug, which binds antiapoptotic BCL-2, BCL-xL, and MCL-1 for inhibition to elicit apoptosis. Survivin is an antiapoptotic protein, whose upregulation correlates with pathogenesis, therapeutic resistance, and poor prognosis in CRC. Herein, we provide the first evidence delineating the functional linkage between Obatoclax and survivin in the context of human CRC cells. In detail, Obatoclax was found to markedly downregulate survivin. This downregulation was mainly achieved via transcriptional repression, as Obatoclax lowered the levels of both survivin mRNA and promoter activity, while blocking proteasomal degradation failed to prevent survivin from downregulation by Obatoclax. Notably, ectopic survivin expression curtailed Obatoclax-induced apoptosis and cytotoxicity, confirming an essential role of survivin downregulation in Obatoclax-elicited anti-CRC effect. Moreover, Obatoclax was found to repress hyperactive WNT/β-catenin signaling activity commonly present in human CRC cells, and, markedly, ectopic expression of dominant-active β-catenin mutant rescued the levels of survivin along with elevated cell viability. We further revealed that, depending on the cell context, Obatoclax suppresses WNT/β-catenin signaling in HCT 116 cells likely via inducing β-catenin destabilization, or by downregulating LEF1 in DLD-1 cells. Collectively, we for the first time define survivin downregulation as a novel, pro-apoptotic mechanism of Obatoclax as a consequence of Obatocalx acting as an antagonist to WNT/β-catenin signaling.
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7
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Cournoyer S, Addioui A, Belounis A, Beaunoyer M, Nyalendo C, Le Gall R, Teira P, Haddad E, Vassal G, Sartelet H. GX15-070 (Obatoclax), a Bcl-2 family proteins inhibitor engenders apoptosis and pro-survival autophagy and increases Chemosensitivity in neuroblastoma. BMC Cancer 2019; 19:1018. [PMID: 31664947 PMCID: PMC6819521 DOI: 10.1186/s12885-019-6195-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 09/24/2019] [Indexed: 12/19/2022] Open
Abstract
Background Neuroblastoma (NB) is a frequent pediatric tumor associated with poor prognosis. The disregulation of Bcl-2, an anti-apoptotic protein, is crucial for the tumoral development and chemoresistance. Autophagy is also implicated in tumor cell survival and chemoresistance. The aim of our study was to demonstrate therapeutic efficiency of GX 15–070, a pan-Bcl-2 family inhibitor, used alone and in combination with conventional drugs or with hydroxychloroquine (HCQ), an autophagy inhibitor. Methods Five neuroblastoma cell lines were tested for the cytotoxic activity of GX 15–070 alone or in combination with cisplatin, doxorubicin, HCQ or Z-VAD-FMK a broad-spectrum caspase inhibitor. Apoptosis and autophagy levels were studied by western-blot and FACS. Orthotopic injections were performed on NOD/LtSz-scid/IL-2Rgamma null mice that were treated with either GX 15–070 alone or in combination with HCQ. Results Synergistic cytotoxicity was observed for the drug combination in all of the 5 neuroblastoma cell lines tested, including MYCN amplified lines and in cancer stem cells. GX 15–070 significantly increased apoptosis and autophagy in neuroblastoma cells as evidenced by increased levels of the autophagy marker, LC3-II. Inhibition of autophagy by HCQ, further increased the cytotoxicity of this combinatorial treatment, suggesting that autophagy induced by these agent plays a cytoprotective role. In vivo, GX 15–070 combined with HCQ significantly decreased the growth of the tumor and the number of distant metastases. Conclusions Based on the synergistic effect of HCQ and GX 15–070 observed in this study, the combination of these two drugs may be utilized as a new therapeutic approach for neuroblastoma.
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Affiliation(s)
- Sonia Cournoyer
- Research Center, Sainte Justine University Hospital Center, Montreal, QC, Canada
| | - Anissa Addioui
- Research Center, Sainte Justine University Hospital Center, Montreal, QC, Canada.,Department of Pathology and Cellular Biology, Université de Montréal, Montreal, QC, Canada
| | - Assila Belounis
- Research Center, Sainte Justine University Hospital Center, Montreal, QC, Canada.,Department of Pathology and Cellular Biology, Université de Montréal, Montreal, QC, Canada
| | - Mona Beaunoyer
- Research Center, Sainte Justine University Hospital Center, Montreal, QC, Canada.,Department of Pediatric Surgery, Sainte-Justine University Hospital Center, Montreal, QC, Canada
| | - Carine Nyalendo
- Research Center, Sainte Justine University Hospital Center, Montreal, QC, Canada
| | - Roxane Le Gall
- Research Center, Sainte Justine University Hospital Center, Montreal, QC, Canada
| | - Pierre Teira
- Research Center, Sainte Justine University Hospital Center, Montreal, QC, Canada.,Department of Pediatric Hemato-Oncology, Sainte-Justine University Hospital Center, Montreal, QC, Canada
| | - Elie Haddad
- Research Center, Sainte Justine University Hospital Center, Montreal, QC, Canada
| | - Gilles Vassal
- Department of Pediatric Oncology, Institut Gustave Roussy, Villejuif, France
| | - Hervé Sartelet
- Research Center, Sainte Justine University Hospital Center, Montreal, QC, Canada. .,Department of Pathology and Cellular Biology, Université de Montréal, Montreal, QC, Canada. .,Département d'anatomie et cytologie pathologiques, Institut de Biologie et Pathologie, CHU A Michallon, 38043, Grenoble cedex 09, France.
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8
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Sengupta S, Sevigny CM, Bhattacharya P, Jordan VC, Clarke R. Estrogen-Induced Apoptosis in Breast Cancers Is Phenocopied by Blocking Dephosphorylation of Eukaryotic Initiation Factor 2 Alpha (eIF2α) Protein. Mol Cancer Res 2019; 17:918-928. [DOI: 10.1158/1541-7786.mcr-18-0481] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 11/15/2018] [Accepted: 01/10/2019] [Indexed: 11/16/2022]
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9
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Obatoclax impairs lysosomal function to block autophagy in cisplatin-sensitive and -resistant esophageal cancer cells. Oncotarget 2018; 7:14693-707. [PMID: 26910910 PMCID: PMC4924745 DOI: 10.18632/oncotarget.7492] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2015] [Accepted: 12/29/2015] [Indexed: 12/13/2022] Open
Abstract
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.
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10
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Abstract
The efficient production, folding, and secretion of proteins is critical for cancer cell survival. However, cancer cells thrive under stress conditions that damage proteins, so many cancer cells overexpress molecular chaperones that facilitate protein folding and target misfolded proteins for degradation via the ubiquitin-proteasome or autophagy pathway. Stress response pathway induction is also important for cancer cell survival. Indeed, validated targets for anti-cancer treatments include molecular chaperones, components of the unfolded protein response, the ubiquitin-proteasome system, and autophagy. We will focus on links between breast cancer and these processes, as well as the development of drug resistance, relapse, and treatment.
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Affiliation(s)
| | - Jeffrey L Brodsky
- Department of Biological Sciences, University of Pittsburgh, A320 Langley Hall, 4249 Fifth Ave, Pittsburgh, PA, 15260, USA.
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11
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Xie Q, Xu Y, Gao W, Zhang Y, Su J, Liu Y, Guo Y, Dou M, Hu K, Sun L. TAT‑fused IP3R‑derived peptide enhances cisplatin sensitivity of ovarian cancer cells by increasing ER Ca2+ release. Int J Mol Med 2017; 41:809-817. [PMID: 29207009 PMCID: PMC5752180 DOI: 10.3892/ijmm.2017.3260] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 10/25/2017] [Indexed: 01/04/2023] Open
Abstract
Ovarian cancer is the most common gynecological malignancy. At present, cisplatin is used to treat ovarian cancer; however, the development of cisplatin resistance during therapy is a common obstacle to achieving favorable outcomes. Recently, the B‑cell lymphoma 2 (Bcl‑2) BH4 domain has been reported to mediate the prosurvival activity of Bcl‑2 in cancer; however, the involvement of the BH4 domain of Bcl‑2 in the cisplatin resistance of ovarian carcinoma cells is not entirely clear. In this study, we observed the cytoplasmic and mitochondrial levels of Ca2+ by confocal laser microscopy. We also detected cell apoptosis using western blot analysis and flow cytometry. The present study demonstrated that TAT‑fused inositol 1,4,5‑trisphosphate receptor‑derived peptide (TAT‑IDPS), which targets the BH4 domain of Bcl‑2, increased cisplatin‑induced Ca2+ flux from the endoplasmic reticulum (ER) into the cytosol and mitochondria. In addition, TAT‑IDPS increased cisplatin‑induced expression of mitochondrial apoptosis‑associated proteins and ER stress‑associated proteins. These results indicated that TAT‑IDPS may enhance the cytotoxicity of cisplatin toward ovarian carcinoma cells by increasing ER Ca2+ release.
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Affiliation(s)
- Qi Xie
- Department of Pathophysiology, Basic College of Medicine, Jilin University, Changchun, Jilin 130021, P.R. China
| | - Ye Xu
- Department of Histology and Embryology, Basic College of Medicine, Jilin Medical University, Jilin, Jilin 132013, P.R. China
| | - Weinan Gao
- Department of Clinical Medicine, College of Clinical Medicine, Jilin University, Changchun, Jilin 130021, P.R. China
| | - Yong Zhang
- Department of Pathophysiology, Basic College of Medicine, Jilin University, Changchun, Jilin 130021, P.R. China
| | - Jing Su
- Department of Pathophysiology, Basic College of Medicine, Jilin University, Changchun, Jilin 130021, P.R. China
| | - Yanan Liu
- Department of Pathophysiology, Basic College of Medicine, Jilin University, Changchun, Jilin 130021, P.R. China
| | - Yuting Guo
- Department of Histology and Embryology, Basic College of Medicine, Jilin Medical University, Jilin, Jilin 132013, P.R. China
| | - Minghan Dou
- Department of Histology and Embryology, Basic College of Medicine, Jilin Medical University, Jilin, Jilin 132013, P.R. China
| | - Kebang Hu
- Department of Urology, First Hospital of Jilin University, Changchun, Jilin 130031, P.R. China
| | - Liankun Sun
- Department of Pathophysiology, Basic College of Medicine, Jilin University, Changchun, Jilin 130021, P.R. China
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12
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Soltanian-Zadeh S, Kikkeri K, Shajahan-Haq AN, Strobl J, Clarke R, Agah M. Breast cancer cell obatoclax response characterization using passivated-electrode insulator-based dielectrophoresis. Electrophoresis 2017; 38:1988-1995. [PMID: 28608427 PMCID: PMC5976885 DOI: 10.1002/elps.201600447] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Revised: 04/07/2017] [Accepted: 06/07/2017] [Indexed: 12/13/2022]
Abstract
Inherent electrical properties of cells can be beneficial to characterize different cell lines and their response to experimental drugs. This paper presents a novel method to characterize the response of breast cancer cells to drug stimuli through use of off-chip passivated-electrode insulator-based dielectrophoresis (OπDEP) and the application of AC electric fields. This work is the first to demonstrate the ability of OπDEP to differentiate between two closely related breast cancer cell lines, LCC1 and LCC9 while assessing their drug sensitivity to an experimental anti-cancer agent, Obatoclax. Although both cell lines are derivatives of estrogen-responsive MCF-7 breast cancer cells, growth of LCC1 is estrogen independent and anti-estrogen responsive, while LCC9 is both estrogen-independent and anti-estrogen resistant. Under the same operating conditions, LCC1 and LCC9 had different DEP profiles. LCC1 cells had a trapping onset (crossover) frequency of 700 kHz and trapping efficiencies between 30-40%, while LCC9 cells had a lower crossover frequency (100 kHz) and showed higher trapping efficiencies of 40-60%. When exposed to the Obatoclax, both cell lines exhibited dose-dependent shifts in DEP crossover frequency and trapping efficiency. Here, DEP results supplemented with cell morphology and proliferation assays help us to understand the response of these breast cancer cells to Obatoclax.
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Affiliation(s)
- Sepeedah Soltanian-Zadeh
- VT MEMS Lab, The Bradley Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - Kruthika Kikkeri
- VT MEMS Lab, The Bradley Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | | | - Jeannine Strobl
- VT MEMS Lab, The Bradley Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - Robert Clarke
- Lombardi Cancer Center, Georgetown University Medical Center, Washington, DC, USA
| | - Masoud Agah
- VT MEMS Lab, The Bradley Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
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13
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Abstract
Mitochondria play a key role in ATP generation, redox homeostasis and regulation of apoptosis. Due to the essential role of mitochondria in metabolism and cell survival, targeting mitochondria in cancer cells is considered as an attractive therapeutic strategy. However, metabolic flexibility in cancer cells may enable the upregulation of compensatory pathways, such as glycolysis to support cancer cell survival when mitochondrial metabolism is inhibited. Thus, compounds capable of both targeting mitochondria and inhibiting glycolysis may be particularly useful to overcome such drug-resistant mechanism. This review provides an update on recent development in the field of targeting mitochondria and novel compounds that impact mitochondria, glycolysis or both. Key challenges in this research area and potential solutions are also discussed.
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14
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Shajahan-Haq AN, Boca SM, Jin L, Bhuvaneshwar K, Gusev Y, Cheema AK, Demas DD, Raghavan KS, Michalek R, Madhavan S, Clarke R. EGR1 regulates cellular metabolism and survival in endocrine resistant breast cancer. Oncotarget 2017; 8:96865-96884. [PMID: 29228577 PMCID: PMC5722529 DOI: 10.18632/oncotarget.18292] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 05/17/2017] [Indexed: 12/12/2022] Open
Abstract
About 70% of all breast cancers are estrogen receptor alpha positive (ER+; ESR1). Many are treated with antiestrogens. Unfortunately, de novo and acquired resistance to antiestrogens is common but the underlying mechanisms remain unclear. Since growth of cancer cells is dependent on adequate energy and metabolites, the metabolomic profile of endocrine resistant breast cancers likely contains features that are deterministic of cell fate. Thus, we integrated data from metabolomic and transcriptomic analyses of ER+ MCF7-derived breast cancer cells that are antiestrogen sensitive (LCC1) or resistant (LCC9) that resulted in a gene-metabolite network associated with EGR1 (early growth response 1). In human ER+ breast tumors treated with endocrine therapy, higher EGR1 expression was associated with a more favorable prognosis. Mechanistic studies showed that knockdown of EGR1 inhibited cell growth in both cells and EGR1 overexpression did not affect antiestrogen sensitivity. Comparing metabolite profiles in LCC9 cells following perturbation of EGR1 showed interruption of lipid metabolism. Tolfenamic acid, an anti-inflammatory drug, decreased EGR1 protein levels and synergized with antiestrogens in inhibiting cell proliferation in LCC9 cells. Collectively, these findings indicate that EGR1 is an important regulator of breast cancer cell metabolism and is a promising target to prevent or reverse endocrine resistance.
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Affiliation(s)
- Ayesha N Shajahan-Haq
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC, USA
| | - Simina M Boca
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC, USA.,Innovation Center for Biomedical Informatics (ICBI), Georgetown University Medical Center, Washington, DC, USA.,Department of Biostatistics, Bioinformatics and Biomathematics, Georgetown University, Washington, DC, USA
| | - Lu Jin
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC, USA
| | - Krithika Bhuvaneshwar
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC, USA.,Innovation Center for Biomedical Informatics (ICBI), Georgetown University Medical Center, Washington, DC, USA
| | - Yuriy Gusev
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC, USA.,Innovation Center for Biomedical Informatics (ICBI), Georgetown University Medical Center, Washington, DC, USA
| | - Amrita K Cheema
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC, USA
| | - Diane D Demas
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC, USA
| | - Kristopher S Raghavan
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC, USA
| | | | - Subha Madhavan
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC, USA.,Innovation Center for Biomedical Informatics (ICBI), Georgetown University Medical Center, Washington, DC, USA
| | - Robert Clarke
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC, USA
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15
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Opydo-Chanek M, Gonzalo O, Marzo I. Multifaceted anticancer activity of BH3 mimetics: Current evidence and future prospects. Biochem Pharmacol 2017; 136:12-23. [PMID: 28288819 DOI: 10.1016/j.bcp.2017.03.006] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Accepted: 03/06/2017] [Indexed: 12/19/2022]
Abstract
BH3 mimetics are a novel class of anticancer agents designed to specifically target pro-survival proteins of the Bcl-2 family. Like endogenous BH3-only proteins, BH3 mimetics competitively bind to surface hydrophobic grooves of pro-survival Bcl-2 family members, counteracting their protective effects and thus facilitating apoptosis in cancer cells. Among the small-molecule BH3 mimetics identified, ABT-737 and its analogs, obatoclax as well as gossypol derivatives are the best characterized. The anticancer potential of these compounds applied as a single agent or in combination with chemotherapeutic drugs is currently being evaluated in preclinical studies and in clinical trials. In spite of promising results, the actual mechanisms of their anticancer action remain to be identified. Findings from preclinical studies point to additional activities of BH3 mimetics in cancer cells that are not connected with apoptosis induction. These off-target effects involve induction of autophagy and necrotic cell death as well as modulation of the cell cycle and multiple cell signaling pathways. For the optimization and clinical implementation of BH3 mimetics, a detailed understanding of their role as inhibitors of the pro-survival Bcl-2 proteins, but also of their possible additional effects is required. This review summarizes the most representative BH3 mimetic compounds with emphasis on their off-target effects. Based on the present knowledge on the multifaceted effects of BH3 mimetics on cancer cells, the commentary outlines the potential pitfalls and highlights the considerable promise for cancer treatment with BH3 mimetics.
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Affiliation(s)
- Małgorzata Opydo-Chanek
- Department of Experimental Hematology, Institute of Zoology, Jagiellonian University in Kraków, Poland.
| | - Oscar Gonzalo
- Department of Biochemistry, Molecular and Cell Biology, IIS, University of Zaragoza, Spain
| | - Isabel Marzo
- Department of Biochemistry, Molecular and Cell Biology, IIS, University of Zaragoza, Spain
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16
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Obatoclax, a Pan-BCL-2 Inhibitor, Targets Cyclin D1 for Degradation to Induce Antiproliferation in Human Colorectal Carcinoma Cells. Int J Mol Sci 2016; 18:ijms18010044. [PMID: 28035994 PMCID: PMC5297679 DOI: 10.3390/ijms18010044] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 12/19/2016] [Accepted: 12/21/2016] [Indexed: 12/20/2022] Open
Abstract
Colorectal cancer is the third most common cancer worldwide. Aberrant overexpression of antiapoptotic BCL-2 (B-cell lymphoma 2) family proteins is closely linked to tumorigenesis and poor prognosis in colorectal cancer. Obatoclax is an inhibitor targeting all antiapoptotic BCL-2 proteins. A previous study has described the antiproliferative action of obatoclax in one human colorectal cancer cell line without elucidating the underlying mechanisms. We herein reported that, in a panel of human colorectal cancer cell lines, obatoclax inhibits cell proliferation, suppresses clonogenicity, and induces G1-phase cell cycle arrest, along with cyclin D1 downregulation. Notably, ectopic cyclin D1 overexpression abrogated clonogenicity suppression but also G1-phase arrest elicited by obatoclax. Mechanistically, pre-treatment with the proteasome inhibitor MG-132 restored cyclin D1 levels in all obatoclax-treated cell lines. Cycloheximide chase analyses further revealed an evident reduction in the half-life of cyclin D1 protein by obatoclax, confirming that obatoclax downregulates cyclin D1 through induction of cyclin D1 proteasomal degradation. Lastly, threonine 286 phosphorylation of cyclin D1, which is essential for initiating cyclin D1 proteasomal degradation, was induced by obatoclax in one cell line but not others. Collectively, we reveal a novel anticancer mechanism of obatoclax by validating that obatoclax targets cyclin D1 for proteasomal degradation to downregulate cyclin D1 for inducing antiproliferation.
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17
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Radhi S. Molecular Changes During Breast Cancer and Mechanisms of Endocrine Therapy Resistance. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2016; 144:539-562. [PMID: 27865467 DOI: 10.1016/bs.pmbts.2016.09.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Estrogen receptors (ERs) are expressed in 75% of breast cancers. ERs and their estrogen ligands play a key role in the development and progression of breast cancer. ERs have a genomic activity involving direct modulation of expression of genes vital to cell growth and survival by their classic nuclear receptors. The nongenomic activity is mediated by membrane receptor tyrosine kinases that activate signaling pathways resulting in activation of ER pathway modulators. Endocrine therapies inhibit the growth promoting activity of estrogen. ERs-positive breast cancers can exhibit de novo or acquired endocrine resistance. The mechanisms of endocrine therapy resistance are complex include deregulation of ER pathway, growth factor receptor signaling, cell cycle machinery, and tumor microenvironment. In this chapter, we will review the literature on the biology of ERs, the postulated mechanisms of endocrine therapy resistance, and their clinical implications.
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Affiliation(s)
- S Radhi
- Texas Tech University Health Science Center, Lubbock, TX, United States.
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18
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Li X, Su J, Xia M, Li H, Xu Y, Ma C, Ma L, Kang J, Yu H, Zhang Z, Sun L. Caspase-mediated cleavage of Beclin1 inhibits autophagy and promotes apoptosis induced by S1 in human ovarian cancer SKOV3 cells. Apoptosis 2016; 21:225-38. [PMID: 26573276 DOI: 10.1007/s10495-015-1197-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
S1, a novel BH3 mimetic, can induce apoptosis dependent on Bax/Bak through inhibition of Bcl-2 in various tumors. S1 also induces autophagy through interrupting the interaction of Bcl-2 and Beclin1. Our results showed that S1 induces apoptosis in human ovarian cancer SKOV3 cells in a time- and dose-dependent manner. Autophagy precedes apoptosis, in SKOV3 cells treated with S1 (6 μmol/L), autophagy reached the maximum peak at 12 h after treatment and decreased to 24 h. In SKOV3 cells treated with different concentrations of S1 for 24 h, the highest level of autophagy was observed with 5 μmol/L and decreased to 10 μmol/L. Autophagy inhibitors 3-MA and CQ enhanced apoptosis induced by S1 in SKOV3 cells. However, overactivation of caspases in apoptosis induced by S1 may inhibit the autophagy-inducing function of Beclin1. Because the pan-caspase inhibitor Z-VAD recovered the autophagy-inducing function of Beclin1 through reduction of activated caspase-mediated cleavage of Beclin1. Furthermore, the Beclin1 cleavage products could further increase apoptosis induced by S1 in SKOV3 cells. This indicates that apoptosis induced by high doses and long exposure of S1 causes the overactivation of caspases and subsequent cleavage of Beclin1, and inhibits the protection of autophagy. Moreover, the cleaved product of Beclin1 further promotes apoptosis induced by S1 in SKOV3 cells. Our results suggest this may be a molecular mechanism for enhancing the sensitivity of cancer cells to apoptosis induced by small molecular compound targeting Bcl-2.
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Affiliation(s)
- Xiaoning Li
- Department of Pathophysiology, Basic Medical College, Jilin University, Changchun, 130021, China
| | - Jing Su
- Department of Pathophysiology, Basic Medical College, Jilin University, Changchun, 130021, China
| | - Meihui Xia
- Department of Obstetrics and Gynecology, Jilin University First Hospital, Changchun, 130021, China
| | - Hongyan Li
- Department of Pathophysiology, Basic Medical College, Jilin University, Changchun, 130021, China
| | - Ye Xu
- Medical Research Laboratory, Jilin Medical College, Jilin, 132013, China
| | - Chunhui Ma
- Department of Pathophysiology, Basic Medical College, Jilin University, Changchun, 130021, China
| | - Liwei Ma
- Department of Pathophysiology, Basic Medical College, Jilin University, Changchun, 130021, China
| | - Jingsong Kang
- Department of Pathophysiology, Basic Medical College, Jilin University, Changchun, 130021, China
| | - Huimei Yu
- Department of Pathogenic Microorganisms, Basic Medical College, Jilin University, Changchun, 130021, China
| | - Zhichao Zhang
- State Key Laboratory of Fine Chemicals, School of Chemistry, Dalian University of Technology, Dalian, 116012, Liaoning, China
| | - Liankun Sun
- Department of Pathophysiology, Basic Medical College, Jilin University, Changchun, 130021, China.
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19
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The p53 tumor suppressor protein protects against chemotherapeutic stress and apoptosis in human medulloblastoma cells. Aging (Albany NY) 2016; 7:854-68. [PMID: 26540407 PMCID: PMC4637210 DOI: 10.18632/aging.100831] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Medulloblastoma (MB), a primitive neuroectodermal tumor, is the most common malignant childhood brain tumor and remains incurable in about a third of patients. Currently, survivors carry a significant burden of late treatment effects. The p53 tumor suppressor protein plays a crucial role in influencing cell survival in response to cellular stress and while the p53 pathway is considered a key determinant of anti-tumor responses in many tumors, its role in cell survival in MB is much less well defined. Herein, we report that the experimental drug VMY-1-103 acts through induction of a partial DNA damage-like response as well induction of non-survival autophagy. Surprisingly, the genetic or chemical silencing of p53 significantly enhanced the cytotoxic effects of both VMY and the DNA damaging drug, doxorubicin. The inhibition of p53 in the presence of VMY revealed increased late stage apoptosis, increased DNA fragmentation and increased expression of genes involved in apoptosis, including CAPN12 and TRPM8, p63, p73, BIK, EndoG, CIDEB, P27Kip1 and P21cip1. These data provide the groundwork for additional studies on VMY as a therapeutic drug and support further investigations into the intriguing possibility that targeting p53 function may be an effective means of enhancing clinical outcomes in MB.
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20
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Champa D, Orlacchio A, Patel B, Ranieri M, Shemetov AA, Verkhusha VV, Cuervo AM, Di Cristofano A. Obatoclax kills anaplastic thyroid cancer cells by inducing lysosome neutralization and necrosis. Oncotarget 2016; 7:34453-71. [PMID: 27144341 PMCID: PMC5085168 DOI: 10.18632/oncotarget.9121] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 04/16/2016] [Indexed: 12/03/2022] Open
Abstract
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.
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Affiliation(s)
- Devora Champa
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Arturo Orlacchio
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Bindi Patel
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Michela Ranieri
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Anton A Shemetov
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Vladislav V Verkhusha
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Ana Maria Cuervo
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Antonio Di Cristofano
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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The BH3 Mimetic Obatoclax Accumulates in Lysosomes and Causes Their Alkalinization. PLoS One 2016; 11:e0150696. [PMID: 26950068 PMCID: PMC4780728 DOI: 10.1371/journal.pone.0150696] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2015] [Accepted: 02/17/2016] [Indexed: 11/25/2022] Open
Abstract
Obatoclax belongs to a class of compounds known as BH3 mimetics which function as antagonists of Bcl-2 family apoptosis regulators. It has undergone extensive preclinical and clinical evaluation as a cancer therapeutic. Despite this, it is clear that obatoclax has additional pharmacological effects that contribute to its cytotoxic activity. It has been claimed that obatoclax, either alone or in combination with other molecularly targeted therapeutics, induces an autophagic form of cell death. In addition, obatoclax has been shown to inhibit lysosomal function, but the mechanism of this has not been elucidated. We have evaluated the mechanism of action of obatoclax in eight ovarian cancer cell lines. Consistent with its function as a BH3 mimetic, obatoclax induced apoptosis in three cell lines. However, in the remaining cell lines another form of cell death was evident because caspase activation and PARP cleavage were not observed. Obatoclax also failed to show synergy with carboplatin and paclitaxel, chemotherapeutic agents which we have previously shown to be synergistic with authentic Bcl-2 family antagonists. Obatoclax induced a profound accumulation of LC-3 but knockdown of Atg-5 or beclin had only minor effects on the activity of obatoclax in cell growth assays suggesting that the inhibition of lysosomal function rather than stimulation of autophagy may play a more prominent role in these cells. To evaluate how obatoclax inhibits lysosomal function, confocal microscopy studies were conducted which demonstrated that obatoclax, which contains two basic pyrrole groups, accumulates in lysosomes. Studies using pH sensitive dyes demonstrated that obatoclax induced lysosomal alkalinization. Furthermore, obatoclax was synergistic in cell growth/survival assays with bafilomycin and chloroquine, two other drugs which cause lysosomal alkalinization. These studies explain, for the first time, how obatoclax inhibits lysosomal function and suggest that lysosomal alkalinization contributes to the cytotoxic activity of obatoclax.
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22
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Clarke R, Tyson JJ, Dixon JM. Endocrine resistance in breast cancer--An overview and update. Mol Cell Endocrinol 2015; 418 Pt 3:220-34. [PMID: 26455641 PMCID: PMC4684757 DOI: 10.1016/j.mce.2015.09.035] [Citation(s) in RCA: 238] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Revised: 09/29/2015] [Accepted: 09/29/2015] [Indexed: 02/07/2023]
Abstract
Tumors that express detectable levels of the product of the ESR1 gene (estrogen receptor-α; ERα) represent the single largest molecular subtype of breast cancer. More women eventually die from ERα+ breast cancer than from either HER2+ disease (almost half of which also express ERα) and/or from triple negative breast cancer (ERα-negative, progesterone receptor-negative, and HER2-negative). Antiestrogens and aromatase inhibitors are largely indistinguishable from each other in their abilities to improve overall survival and almost 50% of ERα+ breast cancers will eventually fail one or more of these endocrine interventions. The precise reasons why these therapies fail in ERα+ breast cancer remain largely unknown. Pharmacogenetic explanations for Tamoxifen resistance are controversial. The role of ERα mutations in endocrine resistance remains unclear. Targeting the growth factors and oncogenes most strongly correlated with endocrine resistance has proven mostly disappointing in their abilities to improve overall survival substantially, particularly in the metastatic setting. Nonetheless, there are new concepts in endocrine resistance that integrate molecular signaling, cellular metabolism, and stress responses including endoplasmic reticulum stress and the unfolded protein response (UPR) that provide novel insights and suggest innovative therapeutic targets. Encouraging evidence that drug combinations with CDK4/CDK6 inhibitors can extend recurrence free survival may yet translate to improvements in overall survival. Whether the improvements seen with immunotherapy in other cancers can be achieved in breast cancer remains to be determined, particularly for ERα+ breast cancers. This review explores the basic mechanisms of resistance to endocrine therapies, concluding with some new insights from systems biology approaches further implicating autophagy and the UPR in detail, and a brief discussion of exciting new avenues and future prospects.
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Affiliation(s)
- Robert Clarke
- Department of Oncology, Georgetown University Medical Center, Washington DC 20057, USA.
| | - John J Tyson
- Department of Biological Sciences, Virginia Polytechnic and State University, Blacksburg, VA 24061, USA
| | - J Michael Dixon
- Edinburgh Breast Unit, Western General Hospital, Edinburgh, UK
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23
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Yu F, Chen Z, Wang B, Jin Z, Hou Y, Ma S, Liu X. The role of lysosome in cell death regulation. Tumour Biol 2015; 37:1427-36. [DOI: 10.1007/s13277-015-4516-6] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 11/25/2015] [Indexed: 02/01/2023] Open
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24
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Koehler BC, Jassowicz A, Scherr AL, Lorenz S, Radhakrishnan P, Kautz N, Elssner C, Weiss J, Jaeger D, Schneider M, Schulze-Bergkamen H. Pan-Bcl-2 inhibitor Obatoclax is a potent late stage autophagy inhibitor in colorectal cancer cells independent of canonical autophagy signaling. BMC Cancer 2015; 15:919. [PMID: 26585594 PMCID: PMC4653869 DOI: 10.1186/s12885-015-1929-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Accepted: 11/12/2015] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Colorectal cancer is the third most common malignancy in humans and novel therapeutic approaches are urgently needed. Autophagy is an evolutionarily highly conserved cellular process by which cells collect unnecessary organelles or misfolded proteins and subsequently degrade them in vesicular structures in order to refuel cells with energy. Dysregulation of the complex autophagy signaling network has been shown to contribute to the onset and progression of cancer in various models. The Bcl-2 family of proteins comprises central regulators of apoptosis signaling and has been linked to processes involved in autophagy. The antiapoptotic members of the Bcl-2 family of proteins have been identified as promising anticancer drug targets and small molecules inhibiting those proteins are in clinical trials. METHODS Flow cytometry and colorimetric assays were used to assess cell growth and cell death. Long term 3D cell culture was used to assess autophagy in a tissue mimicking environment in vitro. RNA interference was applied to modulate autophagy signaling. Immunoblotting and q-RT PCR were used to investigate autophagy signaling. Immunohistochemistry and fluorescence microscopy were used to detect autophagosome formation and autophagy flux. RESULTS This study demonstrates that autophagy inhibition by obatoclax induces cell death in colorectal cancer (CRC) cells in an autophagy prone environment. Here, we demonstrate that pan-Bcl-2 inhibition by obatoclax causes a striking, late stage inhibition of autophagy in CRC cells. In contrast, ABT-737, a Mcl-1 sparing Bcl-2 inhibitor, failed to interfere with autophagy signaling. Accumulation of p62 as well as Light Chain 3 (LC3) was observed in cells treated with obatoclax. Autophagy inhibition caused by obatoclax is further augmented in stressful conditions such as starvation. Furthermore, our data demonstrate that inhibition of autophagy caused by obatoclax is independent of the essential pro-autophagy proteins Beclin-1, Atg7 and Atg12. CONCLUSIONS The objective of this study was to dissect the contribution of Bcl-2 proteins to autophagy in CRC cells and to explore the potential of Bcl-2 inhibitors for autophagy modulation. Collectively, our data argue for a Beclin-1 independent autophagy inhibition by obatoclax. Based on this study, we recommend the concept of autophagy inhibition as therapeutic strategy for CRC.
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Affiliation(s)
- Bruno Christian Koehler
- National Center for Tumor Diseases, Department of Medical Oncology, Internal Medicine VI, Heidelberg University Hospital, Heidelberg, Germany.
| | - Adam Jassowicz
- National Center for Tumor Diseases, Department of Medical Oncology, Internal Medicine VI, Heidelberg University Hospital, Heidelberg, Germany.
| | - Anna-Lena Scherr
- National Center for Tumor Diseases, Department of Medical Oncology, Internal Medicine VI, Heidelberg University Hospital, Heidelberg, Germany.
| | - Stephan Lorenz
- National Center for Tumor Diseases, Department of Medical Oncology, Internal Medicine VI, Heidelberg University Hospital, Heidelberg, Germany.
| | - Praveen Radhakrishnan
- Department of General, Visceral and Transplantation Surgery, University of Heidelberg, Im Neuenheimer Feld 110, 69120, Heidelberg, Germany.
| | - Nicole Kautz
- National Center for Tumor Diseases, Department of Medical Oncology, Internal Medicine VI, Heidelberg University Hospital, Heidelberg, Germany.
| | - Christin Elssner
- National Center for Tumor Diseases, Department of Medical Oncology, Internal Medicine VI, Heidelberg University Hospital, Heidelberg, Germany.
| | - Johanna Weiss
- Department of Clinical Pharmacology and Pharmacoepidemiology, University Hospital Heidelberg, University of Heidelberg, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany.
| | - Dirk Jaeger
- National Center for Tumor Diseases, Department of Medical Oncology, Internal Medicine VI, Heidelberg University Hospital, Heidelberg, Germany.
| | - Martin Schneider
- Department of General, Visceral and Transplantation Surgery, University of Heidelberg, Im Neuenheimer Feld 110, 69120, Heidelberg, Germany.
| | - Henning Schulze-Bergkamen
- National Center for Tumor Diseases, Department of Medical Oncology, Internal Medicine VI, Heidelberg University Hospital, Heidelberg, Germany. .,Department of Internal Medicine II, Marien-Hospital, Wesel, Germany.
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25
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Cook KL, Wärri A, Soto-Pantoja DR, Clarke PA, Cruz MI, Zwart A, Clarke R. Hydroxychloroquine inhibits autophagy to potentiate antiestrogen responsiveness in ER+ breast cancer. Clin Cancer Res 2015; 20:3222-32. [PMID: 24928945 DOI: 10.1158/1078-0432.ccr-13-3227] [Citation(s) in RCA: 156] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Estrogen receptor-α (ERα)-targeted therapies including tamoxifen (TAM) or Faslodex (ICI) are used to treat ER(+) breast cancers. Up to 50% of tumors will acquire resistance to these interventions. Autophagy has been implicated as a major driver of antiestrogen resistance. We have explored the ability of hydroxychloroquine (HCQ), which inhibits autophagy, to affect antiestrogen responsiveness. EXPERIMENTAL DESIGN TAM-resistant MCF7-RR and ICI-resistant/TAM cross-resistant LCC9 ER(+) breast cancer cells were injected into mammary fat pads of female athymic mice and treated with TAM and/or ICI in combination with oral low-dose HCQ. RESULTS We show that HCQ can increase antiestrogen responsiveness in MCF7-RR and LCC9 cells and tumors, likely through the inhibition of autophagy. However, the combination of ICI+HCQ was less effective than HCQ alone in vivo, unlike the TAM+HCQ combination. Antiestrogen treatment stimulated angiogenesis in tumors but did not prevent HCQ effectiveness. The lower efficacy of ICI+HCQ was associated with ICI effects on cell-mediated immunity within the tumor microenvironment. The mouse chemokine KC (CXCL1) and IFNγ were differentially regulated by both TAM and ICI treatments, suggesting a possible effect on macrophage development/activity. Consistent with these observations, TAM+HCQ treatment increased tumor CD68(+) cells infiltration, whereas ICI and ICI+HCQ reduced peripheral tumor macrophage content. Moreover, macrophage elimination of breast cancer target cells in vitro was reduced following exposure to ICI. CONCLUSION HCQ restores antiestrogen sensitivity to resistant tumors. Moreover, the beneficial combination of TAM+HCQ suggests a positive outcome for ongoing neoadjuvant clinical trials using this combination for the treatment of ER(+) ductal carcinoma in situ lesions.
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Affiliation(s)
- Katherine L Cook
- Authors' Affiliations: Department of Oncology and Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, D.C.; and Department of Pathology, National Cancer Institute, NIH, Bethesda, Maryland
| | - Anni Wärri
- Authors' Affiliations: Department of Oncology and Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, D.C.; and Department of Pathology, National Cancer Institute, NIH, Bethesda, Maryland
| | - David R Soto-Pantoja
- Authors' Affiliations: Department of Oncology and Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, D.C.; and Department of Pathology, National Cancer Institute, NIH, Bethesda, Maryland
| | - Pamela Ag Clarke
- Authors' Affiliations: Department of Oncology and Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, D.C.; and Department of Pathology, National Cancer Institute, NIH, Bethesda, Maryland
| | - M Idalia Cruz
- Authors' Affiliations: Department of Oncology and Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, D.C.; and Department of Pathology, National Cancer Institute, NIH, Bethesda, Maryland
| | - Alan Zwart
- Authors' Affiliations: Department of Oncology and Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, D.C.; and Department of Pathology, National Cancer Institute, NIH, Bethesda, Maryland
| | - Robert Clarke
- Authors' Affiliations: Department of Oncology and Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, D.C.; and Department of Pathology, National Cancer Institute, NIH, Bethesda, Maryland
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Zhong D, Gu C, Shi L, Xun T, Li X, Liu S, Yu L. Obatoclax induces G1/G0-phase arrest via p38/p21(waf1/Cip1) signaling pathway in human esophageal cancer cells. J Cell Biochem 2015; 115:1624-35. [PMID: 24788582 DOI: 10.1002/jcb.24829] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 04/29/2014] [Indexed: 12/15/2022]
Abstract
Pan-Bcl-2 family inhibitor obatoclax has been demonstrated to be effective against various cancers, of which the mechanism of action is not fully understood. In this study, we demonstrate that obatoclax suppressed esophageal cancer cell viability with concomitant G1/G0-phase cell cycle arrest. At the tested concentrations (1/2 IC50 and IC50), obatoclax neither induced PARP cleavage nor increased the Annexin V-positive population, suggesting G1/G0-phase arrest rather than apoptosis accounts for most of the reduction of cell viability produced by obatoclax. Double knockdown of Bak and Bax by small interference RNA failed to block obatoclax-induced G1/G0-phase arrest, implying its role in cell cycle progression is Bak/Bax-independent. The cell cycle arresting effect of obatoclax was associated with up-regulation of p21(waf1/Cip1). Knockdown of p21(waf1/Cip1) significantly attenuated obatoclax-induced G1/G0-phase arrest. Although obatoclax stimulated phosphorylation of Erk, p38, and JNK, pharmacological inhibition of p38 but not Erk or JNK blocked obatoclax-induced G1/G0-phase arrest. Moreover, knockdown of p38 abolished the cell cycle arresting effect of obatoclax. In consistent with this finding, inhibition of p38 blocked obatoclax-induced p21(waf1/Cip1) expression while inhibition of Erk or JNK failed to exert similar effect. To conclude, these findings suggest that obatoclax induced cell cycle arrest via p38/p21(waf1/Cip1) signaling pathway. This study may shed a new light on the anti-cancer activity of obatoclax in relation to cell cycle arrest.
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Affiliation(s)
- Desheng Zhong
- School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, China
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Broecker-Preuss M, Viehof J, Jastrow H, Becher-Boveleth N, Fuhrer D, Mann K. Cell death induction by the BH3 mimetic GX15-070 in thyroid carcinoma cells. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2015. [PMID: 26198850 PMCID: PMC4510903 DOI: 10.1186/s13046-015-0186-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Background The evasion of cell death is one of the hallmarks of cancer, contributing to both tumor progression and resistance to therapy. Dedifferentiated and anaplastic thyroid carcinomas that do not take up radioiodine are resistant to conventional anticancer treatments and patients with these tumors are difficult to treat. BH3 mimetics are a new class of drugs that target anti-apoptotic proteins of the BCL-2 family and promote cell death. The purpose of this study was to analyze the molecular effects of the BH3 mimetic GX15-070 on thyroid carcinoma cell lines and to characterize cell death induced by GX15-070. Methods A total of 17 cell lines derived from follicular, papillary, and anaplastic thyroid carcinomas were treated with GX15-070. Cell viability was measured with MTT assay while cell cycle phase distribution and subG1 peaks were determined after propidium iodide staining. We assessed cell death via the caspase 3/7 activity, caspase cleavage products, lactate dehydrogenase (LDH) liberation assays, and a LC3 analysis by western blot. Ultrastructural changes were analysed by electron microscopy of GX15-070-treated cells. Results After GX15-070 treatment, the number of viable cells was decreased in all cell lines examined, with IC50 values ranging from 48nM to 3.25 μM. We observed biochemical markers of autophagic cell death and necrosis like LC3 conversion and LDH release after the GX15-070 treatment. Electron microscopy revealed several common characteristic ultrastructural changes like swelling of mitochondria, dilatation of rough endoplasmic reticulum, membrane blebbing and formation of vacuoles. GX15-070 treatment induced DNA fragmentation detected by subG1-peak induction and an arrest in G1 phase of the cell cycle. Caspase activation after GX15-070 incubation was detected but had no effect on viability of cells. Conclusions With these experiments we demonstrated the efficacy of the BH3 mimetic drug GX15-070 acting against dedifferentiated thyroid carcinoma cells of various histological origins by the induction of cell death. GX15-070-treated cells underwent non-classical cell death with signs of apoptosis, autophagy and necrosis in parallel. GX15-07 and related compounds thus may be a new therapeutic option for dedifferentiated thyroid carcinoma of various histological subtypes.
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Affiliation(s)
- Martina Broecker-Preuss
- Department of Endocrinology and Metabolism, and Division of Laboratory Research, University Hospital Essen, Hufelandstrasse 55, Essen, Germany. .,Present address: Department of Clinical Chemistry, University Hospital Essen, Hufelandstrasse 55, 45122, Essen, Germany.
| | - Jan Viehof
- Department of Endocrinology and Metabolism, and Division of Laboratory Research, University Hospital Essen, Hufelandstrasse 55, Essen, Germany. .,Present address: Ruhrlandklinik, University Hospital Essen, Tüschener Weg 40, 45239, Essen, Germany.
| | - Holger Jastrow
- Institute of Anatomy, University Hospital Essen, Hufelandstrasse 55, Essen, Germany.
| | - Nina Becher-Boveleth
- Department of Endocrinology and Metabolism, and Division of Laboratory Research, University Hospital Essen, Hufelandstrasse 55, Essen, Germany. .,Present address: Clinic of Nuclear Medicine, University Hospital Essen, Hufelandstr. 55, 45122, Essen, Germany.
| | - Dagmar Fuhrer
- Department of Endocrinology and Metabolism, and Division of Laboratory Research, University Hospital Essen, Hufelandstrasse 55, Essen, Germany.
| | - Klaus Mann
- Department of Endocrinology and Metabolism, and Division of Laboratory Research, University Hospital Essen, Hufelandstrasse 55, Essen, Germany. .,Present address: Center of Endocrinology Alter Hof München, Dienerstr. 12, 80331, Munich, Germany.
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Abstract
Oestrogen receptor-positive (ER(+)) breast cancer is a major cause of cancer death in women. Although aromatase inhibitors suppress the function of ER and reduce the risk of recurrence, therapeutic resistance is common and essentially inevitable in advanced disease. This Review considers both genomic and cell biological explanations as to why ER(+) breast cancer cells persist, progress and cause an incurable, lethal, systemic disease. The design and outcomes of clinical trials are considered with the perspective that resistance mechanisms are heterogeneous, and therefore biomarker and somatic mutation-based stratification and eligibility will be essential for improvements in patient outcomes.
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Affiliation(s)
- Cynthia X Ma
- Division of Oncology, Department of Medicine, Siteman Cancer Center, Washington University School of Medicine, 660 South Euclid Avenue, St Louis, Missouri 63110, USA
| | - Tomás Reinert
- Department of Medical Oncology, Instituto Nacional de Câncer (INCA), Praça da Cruz Vermelha, 23, 20230-130, Rio de Janeiro, Brazil
| | - Izabela Chmielewska
- Department of Pneumonology, Oncology and Allergology, Medical University of Lublin, Jaczewskiego 8 St., 20-954, Lublin, Poland
| | - Matthew J Ellis
- Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston 77030, Texas, USA
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Schwartz-Roberts JL, Cook KL, Chen C, Shajahan-Haq AN, Axelrod M, Wärri A, Riggins RB, Jin L, Haddad BR, Kallakury BV, Baumann WT, Clarke R. Interferon regulatory factor-1 signaling regulates the switch between autophagy and apoptosis to determine breast cancer cell fate. Cancer Res 2015; 75:1046-55. [PMID: 25576084 PMCID: PMC4359953 DOI: 10.1158/0008-5472.can-14-1851] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Interferon regulatory factor-1 (IRF1) is a tumor suppressor that regulates cell fate in several cell types. Here, we report an inverse correlation in expression of nuclear IRF1 and the autophagy regulator ATG7 in human breast cancer cells that directly affects their cell fate. In mice harboring mutant Atg7, nuclear IRF1 was increased in mammary tumors, spleen, and kidney. Mechanistic investigations identified ATG7 and the cell death modulator beclin-1 (BECN1) as negative regulators of IRF1. Silencing ATG7 or BECN1 caused estrogen receptor-α to exit the nucleus at the time when IRF1 nuclear localization occurred. Conversely, silencing IRF1 promoted autophagy by increasing BECN1 and blunting IGF1 receptor and mTOR survival signaling. Loss of IRF1 promoted resistance to antiestrogens, whereas combined silencing of ATG7 and IRF1 restored sensitivity to these agents. Using a mathematical model to prompt signaling hypotheses, we developed evidence that ATG7 silencing could resensitize IRF1-attenuated cells to apoptosis through mechanisms that involve other estrogen-regulated genes. Overall, our work shows how inhibiting the autophagy proteins ATG7 and BECN1 can regulate IRF1-dependent and -independent signaling pathways in ways that engender a new therapeutic strategy to attack breast cancer.
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Affiliation(s)
- Jessica L Schwartz-Roberts
- Department of Physiology and Biophysics, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC. Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC
| | - Katherine L Cook
- Department of Physiology and Biophysics, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC. Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC
| | - Chun Chen
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia. Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
| | - Ayesha N Shajahan-Haq
- Department of Physiology and Biophysics, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC. Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC
| | - Margaret Axelrod
- Department of Physiology and Biophysics, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC. Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC
| | - Anni Wärri
- Department of Physiology and Biophysics, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC. Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC
| | - Rebecca B Riggins
- Department of Physiology and Biophysics, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC. Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC
| | - Lu Jin
- Department of Physiology and Biophysics, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC. Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC
| | - Bassem R Haddad
- Department of Physiology and Biophysics, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC. Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC
| | - Bhaskar V Kallakury
- Department of Pathology, Georgetown University Medical Center, Washington, DC
| | - William T Baumann
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia. Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
| | - Robert Clarke
- Department of Physiology and Biophysics, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC. Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC.
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Xie T, Li SJ, Guo MR, Wu Y, Wang HY, Zhang K, Zhang X, Ouyang L, Liu J. Untangling knots between autophagic targets and candidate drugs, in cancer therapy. Cell Prolif 2015; 48:119-39. [PMID: 25650136 DOI: 10.1111/cpr.12167] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Accepted: 10/05/2014] [Indexed: 02/05/2023] Open
Abstract
Autophagy is an evolutionarily conserved lysosomal mechanism implicated in a wide variety of pathological processes, such as cancer. Autophagy can be regulated by a limited number of autophagy-related genes (Atgs) such as oncogenic Bcl-2/Bcl-XL , mTORC1, Akt and PI3KCI, and tumour suppressive proteins PI3KCIII, Beclin-1, Bif-1, p53, DAPKs, PTEN and UVRAG, which play their crucial roles in regulating autophagy-related cancer. As autophagy has a dual role in cancer cells, with tumour-promoting and tumour-suppressing properties, it has become an attractive target for a series of emerging small molecule drugs. In this review, we reveal new discoveries of related small molecules or chemical compounds that can regulate autophagic pathways and lead to pro-death or pro-survival autophagy, in different types of cancer. We discuss the knots between autophagic targets and candidate drugs, in the hope of shedding new light on exploiting new anti-tumour small molecule drugs for future cancer therapy.
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Affiliation(s)
- Tao Xie
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041, China
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31
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Cell death by autophagy: emerging molecular mechanisms and implications for cancer therapy. Oncogene 2015; 34:5105-13. [PMID: 25619832 DOI: 10.1038/onc.2014.458] [Citation(s) in RCA: 246] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Revised: 12/11/2014] [Accepted: 12/12/2014] [Indexed: 12/16/2022]
Abstract
Autophagy is a tightly-regulated catabolic process of cellular self-digestion by which cellular components are targeted to lysosomes for their degradation. Key functions of autophagy are to provide energy and metabolic precursors under conditions of starvation and to alleviate stress by removal of damaged proteins and organelles, which are deleterious for cell survival. Therefore, autophagy appears to serve as a pro-survival stress response in most settings. However, the role of autophagy in modulating cell death is highly dependent on the cellular context and its extent. There is an increasing evidence for cell death by autophagy, in particular in developmental cell death in lower organisms and in autophagic cancer cell death induced by novel cancer drugs. The death-promoting and -executing mechanisms involved in the different paradigms of autophagic cell death (ACD) are very diverse and complex, but a draft scenario of the key molecular targets involved in ACD is beginning to emerge. This review provides an up-to-date and comprehensive report on the molecular mechanisms of drug-induced autophagy-dependent cell death and highlights recent key findings in this exciting field of research.
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32
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Su JC, Chang JH, Huang JW, Chen PPY, Chen KF, Tseng PH, Shiau CW. Copper-obatoclax derivative complexes mediate DNA cleavage and exhibit anti-cancer effects in hepatocellular carcinoma. Chem Biol Interact 2015; 228:108-13. [PMID: 25598309 DOI: 10.1016/j.cbi.2014.12.026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Revised: 12/01/2014] [Accepted: 12/18/2014] [Indexed: 11/19/2022]
Abstract
Obatoclax is an indole-pyrrole compound that induces cancer cell apoptosis through targeting the anti-apoptotic Bcl-2 protein family. Previously, we developed a series of obatoclax derivatives and studied their STAT3 inhibition-dependent activity against cancer cell lines. The obatoclax analog, prodigiosin, has been reported to mediate DNA cleavage in cancer cells by coordinating with copper complexes. To gain an understanding of copper-obatoclax complex activity, we applied obatoclax derivatives to examine their copper-mediated nuclease activity as a means to establish a basis for structure activity relationship. Replacement of the indole ring of obatoclax with furanyl, thiophenyl or Boc-indolyl rings reduced the DNA cleavage ability. The same effect was achieved through the replacement of the obatoclax pyrrolyl ring with thiazolidinedione and thioacetal. Among the compounds tested, we demonstrated that the complex of obatoclax or compound 7 with copper exhibited potent DNA strand scission which correlated with HCC cell growth inhibition.
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Affiliation(s)
- Jung-Chen Su
- Institute of Biopharmaceutical Sciences, National Yang-Ming University, Taipei, Taiwan
| | - Jung-Hua Chang
- Institute of Biopharmaceutical Sciences, National Yang-Ming University, Taipei, Taiwan
| | - Jui-Wen Huang
- Cell Engineering Lab, Biomedical Technology and Device Research Labs, I Industrial Technology Research Institute, Hsinchu, Taiwan
| | - Peter P-Y Chen
- Department of Chemistry, National Chung Hsing University, Taichung, Taiwan
| | - Kuen-Feng Chen
- Department of Medical Research, National Taiwan University Hospital, Taipei, Taiwan; National Center of Excellence for Clinical Trial and Research, National Taiwan University Hospital, Taipei, Taiwan
| | - Ping-Hui Tseng
- Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei, Taiwan.
| | - Chung-Wai Shiau
- Institute of Biopharmaceutical Sciences, National Yang-Ming University, Taipei, Taiwan.
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Cook KL, Soto-Pantoja DR, Jin L, Abu-Asab M, Clarke R. When is a vesicle not just a vesicle: mitochondrial spheroids and mitochondrial autophagosomes. Cell Biosci 2014; 4:66. [PMID: 25699171 PMCID: PMC4332965 DOI: 10.1186/2045-3701-4-66] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Accepted: 10/21/2014] [Indexed: 02/05/2023] Open
Affiliation(s)
- Katherine L Cook
- Department of Oncology and Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC 20057 USA
| | - David R Soto-Pantoja
- Laboratory of Pathology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892 USA
| | - Lu Jin
- Department of Oncology and Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC 20057 USA
| | - Mones Abu-Asab
- National Eye Institute, National Institutes of Health, Bethesda, MD 20892 USA
| | - Robert Clarke
- Department of Oncology and Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC 20057 USA
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Shajahan-Haq AN, Cook KL, Schwartz-Roberts JL, Eltayeb AE, Demas DM, Warri AM, Facey COB, Hilakivi-Clarke LA, Clarke R. MYC regulates the unfolded protein response and glucose and glutamine uptake in endocrine resistant breast cancer. Mol Cancer 2014; 13:239. [PMID: 25339305 PMCID: PMC4216870 DOI: 10.1186/1476-4598-13-239] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Accepted: 10/10/2014] [Indexed: 02/06/2023] Open
Abstract
Background About 70% of all breast cancers are estrogen receptor alpha positive (ER+) and are treated with antiestrogens. However, 50% of ER + tumors develop resistance to these drugs (endocrine resistance). In endocrine resistant cells, an adaptive pathway called the unfolded protein response (UPR) is elevated that allows cells to tolerate stress more efficiently than in sensitive cells. While the precise mechanism remains unclear, the UPR can trigger both pro-survival and pro-death outcomes that depend on the nature and magnitude of the stress. In this study, we identified MYC, an oncoprotein that is upregulated in endocrine resistant breast cancer, as a regulator of the UPR in glucose-deprived conditions. Methods ER+ human breast cancer cell lines (LCC1, LCC1, LY2 and LCC9) and rat mammary tumors were used to confirm upregulation of MYC in endocrine resistance. To evaluate functional relevance of proteins, siRNA-mediated inhibition or small molecule inhibitors were used. Cell density/number was evaluated with crystal violet assay; cell cycle and apoptosis were measured by flow cytometry. Relative quantification of glutamine metabolites were determined by mass spectrometry. Signaling molecules of the UPR, apoptosis or autophagy pathways were investigated by western blotting. Results Increased MYC function in resistant cells correlated with increased dependency on glutamine and glucose for survival. Inhibition of MYC reduced cell growth and uptake of both glucose and glutamine in resistant cells. Interestingly, in glucose-deprived conditions, glutamine induced apoptosis and necrosis, arrested autophagy, and triggered the unfolded protein response (UPR) though GRP78-IRE1α with two possible outcomes: (i) inhibition of cell growth by JNK activation in most cells and, (ii) promotion of cell growth by spliced XBP1 in the minority of cells. These disparate effects are regulated, at different signaling junctions, by MYC more robustly in resistant cells. Conclusions Endocrine resistant cells overexpress MYC and are better adapted to withstand periods of glucose deprivation and can use glutamine in the short term to maintain adequate metabolism to support cell survival. Our findings reveal a unique role for MYC in regulating cell fate through the UPR, and suggest that targeting glutamine metabolism may be a novel strategy in endocrine resistant breast cancer.
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Affiliation(s)
- Ayesha N Shajahan-Haq
- Lombardi Comprehensive Cancer Center and Department of Oncology, Georgetown University School of Medicine, 3970 Reservoir Road NW, Washington, DC 20057, USA.
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Ringer L, Sirajuddin P, Tricoli L, Waye S, Choudhry MU, Parasido E, Sivakumar A, Heckler M, Naeem A, Abdelgawad I, Liu X, Feldman AS, Lee RJ, Wu CL, Yenugonda V, Kallakury B, Dritschilo A, Lynch J, Schlegel R, Rodriguez O, Pestell RG, Avantaggiati ML, Albanese C. The induction of the p53 tumor suppressor protein bridges the apoptotic and autophagic signaling pathways to regulate cell death in prostate cancer cells. Oncotarget 2014; 5:10678-91. [PMID: 25296977 PMCID: PMC4279402 DOI: 10.18632/oncotarget.2528] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 09/25/2014] [Indexed: 12/26/2022] Open
Abstract
The p53 tumor suppressor protein plays a crucial role in influencing cell fate decisions in response to cellular stress. As p53 elicits cell cycle arrest, senescence or apoptosis, the integrity of the p53 pathway is considered a key determinant of anti-tumor responses. p53 can also promote autophagy, however the role of p53-dependent autophagy in chemosensitivity is poorly understood. VMY-1-103 (VMY), a dansylated analog of purvalanol B, displays rapid and potent anti-tumor activities, however the pathways by which VMY works are not fully defined. Using established prostate cancer cell lines and novel conditionally reprogrammed cells (CRCs) derived from prostate cancer patients; we have defined the mechanisms of VMY-induced prostate cancer cell death. Herein, we show that the cytotoxic effects of VMY required a p53-dependent induction of autophagy, and that inhibition of autophagy abrogated VMY-induced cell death. Cancer cell lines harboring p53 missense mutations evaded VMY toxicity and treatment with a small molecule compound that restores p53 activity re-established VMY-induced cell death. The elucidation of the molecular mechanisms governing VMY-dependent cell death in cell lines, and importantly in CRCs, provides the rationale for clinical studies of VMY, alone or in combination with p53 reactivating compounds, in human prostate cancer.
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Affiliation(s)
- Lymor Ringer
- 1 Department of Oncology and Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC, USA
| | - Paul Sirajuddin
- 1 Department of Oncology and Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC, USA
| | - Lucas Tricoli
- 1 Department of Oncology and Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC, USA
| | - Sarah Waye
- 1 Department of Oncology and Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC, USA
| | - Muhammad Umer Choudhry
- 1 Department of Oncology and Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC, USA
| | - Erika Parasido
- 1 Department of Oncology and Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC, USA
| | - Angiela Sivakumar
- 1 Department of Oncology and Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC, USA
| | - Mary Heckler
- 1 Department of Oncology and Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC, USA
| | - Aisha Naeem
- 1 Department of Oncology and Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC, USA
| | - Iman Abdelgawad
- 1 Department of Oncology and Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC, USA,6 National Cancer Institute of Egypt, Cairo, Egypt
| | - Xuefeng Liu
- 2 Department of Pathology, Georgetown University Medical Center, Washington, DC, USA
| | | | | | - Chin-Lee Wu
- 3 Massachusetts General Hospital, Boston, USA
| | - Venkata Yenugonda
- 1 Department of Oncology and Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC, USA
| | - Bhaskar Kallakury
- 2 Department of Pathology, Georgetown University Medical Center, Washington, DC, USA
| | | | - John Lynch
- 4 Georgetown University Hospital, Washington, DC, USA
| | - Richard Schlegel
- 1 Department of Oncology and Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC, USA,2 Department of Pathology, Georgetown University Medical Center, Washington, DC, USA
| | - Olga Rodriguez
- 1 Department of Oncology and Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC, USA
| | - Richard G. Pestell
- 5 Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA
| | - Maria Laura Avantaggiati
- 1 Department of Oncology and Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC, USA
| | - Chris Albanese
- 1 Department of Oncology and Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC, USA,2 Department of Pathology, Georgetown University Medical Center, Washington, DC, USA
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Targeting SQSTM1/p62 induces cargo loading failure and converts autophagy to apoptosis via NBK/Bik. Mol Cell Biol 2014; 34:3435-49. [PMID: 25002530 DOI: 10.1128/mcb.01383-13] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
In selective autophagy, the adaptor protein SQSTM1/p62 plays a critical role in recognizing/loading cargo (e.g., malfolded proteins) into autophagosomes for lysosomal degradation. Here we report that whereas SQSTM1/p62 levels fluctuated in a time-dependent manner during autophagy, inhibition or knockdown of Cdk9/cyclin T1 transcriptionally downregulated SQSTM1/p62 but did not affect autophagic flux. These interventions, or short hairpin RNA (shRNA) directly targeting SQSTM1/p62, resulted in cargo loading failure and inefficient autophagy, phenomena recently described for Huntington's disease neurons. These events led to the accumulation of the BH3-only protein NBK/Bik on endoplasmic reticulum (ER) membranes, most likely by blocking loading and autophagic degradation of NBK/Bik, culminating in apoptosis. Whereas NBK/Bik upregulation was further enhanced by disruption of distal autophagic events (e.g., autophagosome maturation) by chloroquine (CQ) or Lamp2 shRNA, it was substantially diminished by inhibition of autophagy initiation (e.g., genetically by shRNA targeting Ulk1, beclin-1, or Atg5 or pharmacologically by 3-methyladenine [3-MA] or spautin-1), arguing that NBK/Bik accumulation stems from inefficient autophagy. Finally, NBK/Bik knockdown markedly attenuated apoptosis in vitro and in vivo. Together, these findings identify novel cross talk between autophagy and apoptosis, wherein targeting SQSTM1/p62 converts cytoprotective autophagy to an inefficient form due to cargo loading failure, leading to NBK/Bik accumulation, which triggers apoptosis.
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Wroblewski D, Jiang CC, Croft A, Farrelly ML, Zhang XD, Hersey P. OBATOCLAX and ABT-737 induce ER stress responses in human melanoma cells that limit induction of apoptosis. PLoS One 2013; 8:e84073. [PMID: 24367627 PMCID: PMC3868604 DOI: 10.1371/journal.pone.0084073] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Accepted: 11/12/2013] [Indexed: 02/07/2023] Open
Abstract
Anti-apoptotic Bcl-2 family proteins, in particular, Mcl-1, are known to play a critical role in resistance of human melanoma cells to induction of apoptosis by endoplasmic reticulum stress and other agents. The present study examined whether the BH3 mimetics, Obatoclax and ABT-737, which inhibit multiple anti-apoptotic Bcl-2 family proteins, would overcome resistance to apoptosis. We report that both agents induced a strong unfolded protein response (UPR) and that RNAi knockdown of UPR signalling proteins ATF6, IRE1α and XBP-1 inhibited Mcl-1 upregulation and increased sensitivity to the agents. These results demonstrate that inhibition of anti-apoptotic Bcl-2 proteins by Obatoclax and ABT-737 appears to elicit a protective feedback response in melanoma cells, by upregulation of Mcl-1 via induction of the UPR. We also report that Obatoclax, but not ABT-737, strongly induces autophagy, which appears to play a role in determining melanoma sensitivity to the agents.
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Affiliation(s)
- David Wroblewski
- School of Medicine and Public Health, University of Newcastle, New South Wales, Australia
| | - Chen Chen Jiang
- School of Medicine and Public Health, University of Newcastle, New South Wales, Australia
| | - Amanda Croft
- School of Medicine and Public Health, University of Newcastle, New South Wales, Australia
| | - Margaret L. Farrelly
- School of Medicine and Public Health, University of Newcastle, New South Wales, Australia
| | - Xu Dong Zhang
- School of Medicine and Public Health, University of Newcastle, New South Wales, Australia
| | - Peter Hersey
- Kolling Institute, Royal North Shore Hospital, University of Sydney, New South Wales, Australia
- * E-mail:
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Yu L, Liu S. Autophagy contributes to modulating the cytotoxicities of Bcl-2 homology domain-3 mimetics. Semin Cancer Biol 2013; 23:553-60. [PMID: 24012660 DOI: 10.1016/j.semcancer.2013.08.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Accepted: 08/27/2013] [Indexed: 01/08/2023]
Abstract
The dysregulation of apoptosis is a key step in developing cancers, and mediates resistance to cancer therapy. Commitment to apoptosis is caused by permeabilization of the outer mitochondrial membrane, a process regulated by the interactions between different proteins of Bcl-2 family. Furthermore, Bcl-2 family proteins also bind to the endoplasmic reticulum, where they modulate autophagy, another important pathway regulating cell survival and death. Dysregulation of Bcl-2 family has been demonstrated in a wide spectrum of human cancers, including gastrointestinal cancers. Therefore, targeting the Bcl-2 family of proteins represents a promising therapeutic approach for these malignancies. Recent advances have yielded small molecules that have close structural or functional similarity to BH3-only proteins and are therefore named BH3 mimetics. Of these BH3 mimetics, obatoclax, (-)-gossypol, and ABT-263 are currently in clinical trials for multiple cancers. Growing evidence indicates that these BH3 mimetics not only induce apoptosis, but also regulate autophagy which may serve as a pro-survival or pro-death mechanism to counteract or mediate the cytotoxicity of BH3 mimetics. This review discusses the role of autophagy in cell-fate decision upon BH3 mimetics treatment. Further exploration of our understanding of the association between autophagy and cellular outcomes in response to BH3 mimetics treatment will likely offer improved therapies for patients with cancer.
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Affiliation(s)
- Le Yu
- School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, China.
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Lipton P. Lysosomal membrane permeabilization as a key player in brain ischemic cell death: a "lysosomocentric" hypothesis for ischemic brain damage. Transl Stroke Res 2013; 4:672-84. [PMID: 24323421 DOI: 10.1007/s12975-013-0301-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Revised: 10/21/2013] [Accepted: 10/23/2013] [Indexed: 12/13/2022]
Abstract
This is a speculative review of the role of the lysosome in ischemic cell death in the mammalian brain. In particular, it focuses on the role of the permeabilization of the lysosomal membrane to proteins (LMP) as a major mechanism of cell death in mild, but lethal, ischemic insults. The first section of the review outlines the evidence that this is the case, using the relatively few extant studies of mammalian brain. In the second section of the review, the mechanism by which an ischemic insult might lead to LMP is discussed. A metabolic sequence including NMDA receptor activation, activation of phospholipase A2 and production of free radicals, and also the activation of calpain are shown to be critical. The remainder of the section speculates on the actual agent(s) which may be causing the lysosomal membrane change, based on extensive literature references. There is currently no knowledge of the actual mechanism. The third section considers potential targets of the released lysosomal proteases and other proteins that might mediate the lethal effects of LMP, focusing largely on the mitochondria as the target. Again, this is speculative as the targets are not known. Finally, the fourth section addresses the level of importance that LMP has in the process of ischemic cell death and concludes that it may well play the major role during mild but lethal ischemic insults. This novel, so-called "lysosomocentric," hypothesis is briefly critiqued. The therapeutic potential of this conclusion is then discussed.
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Affiliation(s)
- Peter Lipton
- Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, WI, 53706, USA,
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Lorin S, Hamaï A, Mehrpour M, Codogno P. Autophagy regulation and its role in cancer. Semin Cancer Biol 2013; 23:361-79. [DOI: 10.1016/j.semcancer.2013.06.007] [Citation(s) in RCA: 184] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Revised: 06/12/2013] [Accepted: 06/18/2013] [Indexed: 12/11/2022]
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