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Coutinho LL, Femino EL, Gonzalez AL, Moffat RL, Heinz WF, Cheng RYS, Lockett SJ, Rangel MC, Ridnour LA, Wink DA. NOS2 and COX-2 Co-Expression Promotes Cancer Progression: A Potential Target for Developing Agents to Prevent or Treat Highly Aggressive Breast Cancer. Int J Mol Sci 2024; 25:6103. [PMID: 38892290 PMCID: PMC11173351 DOI: 10.3390/ijms25116103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 05/24/2024] [Accepted: 05/29/2024] [Indexed: 06/21/2024] Open
Abstract
Nitric oxide (NO) and reactive nitrogen species (RNS) exert profound biological impacts dictated by their chemistry. Understanding their spatial distribution is essential for deciphering their roles in diverse biological processes. This review establishes a framework for the chemical biology of NO and RNS, exploring their dynamic reactions within the context of cancer. Concentration-dependent signaling reveals distinctive processes in cancer, with three levels of NO influencing oncogenic properties. In this context, NO plays a crucial role in cancer cell proliferation, metastasis, chemotherapy resistance, and immune suppression. Increased NOS2 expression correlates with poor survival across different tumors, including breast cancer. Additionally, NOS2 can crosstalk with the proinflammatory enzyme cyclooxygenase-2 (COX-2) to promote cancer progression. NOS2 and COX-2 co-expression establishes a positive feed-forward loop, driving immunosuppression and metastasis in estrogen receptor-negative (ER-) breast cancer. Spatial evaluation of NOS2 and COX-2 reveals orthogonal expression, suggesting the unique roles of these niches in the tumor microenvironment (TME). NOS2 and COX2 niche formation requires IFN-γ and cytokine-releasing cells. These niches contribute to poor clinical outcomes, emphasizing their role in cancer progression. Strategies to target these markers include direct inhibition, involving pan-inhibitors and selective inhibitors, as well as indirect approaches targeting their induction or downstream effectors. Compounds from cruciferous vegetables are potential candidates for NOS2 and COX-2 inhibition offering therapeutic applications. Thus, understanding the chemical biology of NO and RNS, their spatial distribution, and their implications in cancer progression provides valuable insights for developing targeted therapies and preventive strategies.
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Affiliation(s)
- Leandro L. Coutinho
- Cancer Innovation Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA; (L.L.C.); (E.L.F.); (A.L.G.); (R.Y.S.C.)
- Center for Translational Research in Oncology, ICESP/HC, Faculdade de Medicina da Universidade de São Paulo and Comprehensive Center for Precision Oncology, Universidade de São Paulo, São Paulo 01246-000, SP, Brazil;
| | - Elise L. Femino
- Cancer Innovation Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA; (L.L.C.); (E.L.F.); (A.L.G.); (R.Y.S.C.)
| | - Ana L. Gonzalez
- Cancer Innovation Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA; (L.L.C.); (E.L.F.); (A.L.G.); (R.Y.S.C.)
| | - Rebecca L. Moffat
- Optical Microscopy and Analysis Laboratory, Office of Science and Technology Resources, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA;
| | - William F. Heinz
- Optical Microscopy and Analysis Laboratory, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA; (W.F.H.); (S.J.L.)
| | - Robert Y. S. Cheng
- Cancer Innovation Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA; (L.L.C.); (E.L.F.); (A.L.G.); (R.Y.S.C.)
| | - Stephen J. Lockett
- Optical Microscopy and Analysis Laboratory, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA; (W.F.H.); (S.J.L.)
| | - M. Cristina Rangel
- Center for Translational Research in Oncology, ICESP/HC, Faculdade de Medicina da Universidade de São Paulo and Comprehensive Center for Precision Oncology, Universidade de São Paulo, São Paulo 01246-000, SP, Brazil;
| | - Lisa A. Ridnour
- Cancer Innovation Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA; (L.L.C.); (E.L.F.); (A.L.G.); (R.Y.S.C.)
| | - David A. Wink
- Cancer Innovation Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA; (L.L.C.); (E.L.F.); (A.L.G.); (R.Y.S.C.)
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Hou G, Hu W, Sang Y, Gan X, Xu H, Hu Q, Cao X. Corynoxine triggers cell death via activating PP2A and regulating AKT-mTOR/GSK3β axes in NSCLC. Biochem Pharmacol 2024; 222:116110. [PMID: 38460908 DOI: 10.1016/j.bcp.2024.116110] [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: 12/17/2023] [Revised: 02/16/2024] [Accepted: 03/05/2024] [Indexed: 03/11/2024]
Abstract
This study investigates the anticancer activity and pharmacological mechanisms of Corynoxine (Cory) in non-small cell lung cancer (NSCLC). Cory, a natural product derived from the Chinese herbal medicine Uncaria rhynchophylla, demonstrates promising pharmacological activity. Cell proliferation and viability were evaluated via MTT and colony formation assays. Flow cytometry was employed to analyze cell apoptosis, cycle distribution, and mitochondrial membrane potential. Autophagy was detected using fluorescence microscopy and electron microscopy. Western blotting, protein overexpression, gene knockdown, co-immunoprecipitation, and bioinformatics characterized Cory's impact on signaling pathways. The research indicates that Cory inhibits the proliferation of NSCLC cells in vivo and in vitro. Cory enhances PP2A activity, inhibits the AKT/mTOR signaling pathway triggering autophagy, while suppressing the AKT/GSK3β signaling pathway to induce cellular apoptosis in NSCLC. Notably, the activation of PP2A plays a crucial role in Cory's antitumor effects by inhibiting AKT. In vivo experiments validated Cory's efficacy in NSCLC treatment. These findings highlight the promising role of Cory as a lead compound for drug development in NSCLC therapy, providing a viable option for addressing this challenging disease.
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Affiliation(s)
- Guoqing Hou
- School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei, China; School of Medicine, Taizhou University, Taizhou 318000, Zhejiang, China
| | - Weihua Hu
- Department of Orthopedics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei, China
| | - Yazhou Sang
- School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei, China
| | - Xiaocai Gan
- School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei, China
| | - Hui Xu
- School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei, China
| | - Qiongying Hu
- School of Medicine, Taizhou University, Taizhou 318000, Zhejiang, China.
| | - Xuan Cao
- School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei, China; School of Medicine, Taizhou University, Taizhou 318000, Zhejiang, China.
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Relationship Between the MicroRNAs and PI3K/AKT/mTOR Axis: Focus on Non-Small Cell Lung Cancer. Pathol Res Pract 2022; 239:154093. [DOI: 10.1016/j.prp.2022.154093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 08/19/2022] [Accepted: 08/23/2022] [Indexed: 11/21/2022]
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Wang L, Bharti, Kumar R, Pavlov PF, Winblad B. Small molecule therapeutics for tauopathy in Alzheimer's disease: Walking on the path of most resistance. Eur J Med Chem 2020; 209:112915. [PMID: 33139110 DOI: 10.1016/j.ejmech.2020.112915] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Revised: 10/02/2020] [Accepted: 10/05/2020] [Indexed: 12/19/2022]
Abstract
Alzheimer's disease (AD) is the most common form of dementia characterized by presence of extracellular amyloid plaques and intracellular neurofibrillary tangles composed of tau protein. Currently there are close to 50 million people living with dementia and this figure is expected to increase to 75 million by 2030 putting a huge burden on the economy due to the health care cost. Considering the effects on quality of life of patients and the increasing burden on the economy, there is an enormous need of new disease modifying therapies to tackle this disease. The current therapies are dominated by only symptomatic treatments including cholinesterase inhibitors and N-methyl-D-aspartate receptor blockers but no disease modifying treatments exist so far. After several failed attempts to develop drugs against amyloidopathy, tau targeting approaches have been in the main focus of drug development against AD. After an overview of the tauopathy in AD, this review summarizes recent findings on the development of small molecules as therapeutics targeting tau modification, aggregation, and degradation, and tau-oriented multi-target directed ligands. Overall, this work aims to provide a comprehensive and critical overview of small molecules which are being explored as a lead candidate for discovering drugs against tauopathy in AD.
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Affiliation(s)
- Lisha Wang
- Dept. of Neuroscience Care and Society, Div. of Neurogeriatrics, Karolinska Institutet, 17164, Solna, Sweden
| | - Bharti
- Department of Pharmaceutical Engineering & Technology, Indian Institute of Technology (BHU), Varanasi, 221005, India
| | - Rajnish Kumar
- Dept. of Neuroscience Care and Society, Div. of Neurogeriatrics, Karolinska Institutet, 17164, Solna, Sweden; Department of Pharmaceutical Engineering & Technology, Indian Institute of Technology (BHU), Varanasi, 221005, India
| | - Pavel F Pavlov
- Dept. of Neuroscience Care and Society, Div. of Neurogeriatrics, Karolinska Institutet, 17164, Solna, Sweden; Memory Clinic, Theme Aging, Karolinska University Hospital, 14186, Huddinge, Sweden
| | - Bengt Winblad
- Dept. of Neuroscience Care and Society, Div. of Neurogeriatrics, Karolinska Institutet, 17164, Solna, Sweden; Memory Clinic, Theme Aging, Karolinska University Hospital, 14186, Huddinge, Sweden.
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Hu ZG, Dong ZQ, Dong FF, Zhu Y, Chen P, Lu C, Pan MH. Identification of a PP2A gene in Bombyx mori with antiviral function against B. mori nucleopolyhedrovirus. INSECT SCIENCE 2020; 27:687-696. [PMID: 31070299 DOI: 10.1111/1744-7917.12678] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 04/11/2019] [Accepted: 04/28/2019] [Indexed: 06/09/2023]
Abstract
Ser/Thr protein phosphatase 2A (PP2A) is one of the type 2 protein phosphatases, which is required for many intracellular physiological processes and pathogen infection. However, the function of PP2A is unclear in silkworm, Bombyx mori. Here, we cloned and identified BmPP2A, a PP2A gene from B. mori, which has two HEAT domains and a high similarity to PP2A from other organisms. Our results showed that BmPP2A is localized in the cytoplasm and highly expressed in silkworm epidermis and midgut, and that Bombyx mori nucleopolyhedrovirus (BmNPV) infection induces down-regulation of BmPP2A expression. Furthermore, up-regulation of BmPP2A via overexpression significantly inhibited BmNPV multiplication. In contrast, down-regulation of BmPP2A via RNA interference and okadaic acid (a PP2A inhibitor) treatment allowed robust BmNPV replication. This is the first report of PP2A having an antiviral effect in silkworm and provides insights into the function of BmPP2A, a potential anti-BmNPV mechanism, and a possible target for the breeding of silkworm-resistant strains.
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Affiliation(s)
- Zhi-Gang Hu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Zhan-Qi Dong
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Fei-Fan Dong
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Yan Zhu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Peng Chen
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Cheng Lu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
- Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture, Southwest University, Chongqing, China
| | - Min-Hui Pan
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
- Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture, Southwest University, Chongqing, China
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6
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Wei H, Zhang HL, Xie JZ, Meng DL, Wang XC, Ke D, Zeng J, Liu R. Protein Phosphatase 2A as a Drug Target in the Treatment of Cancer and Alzheimer's Disease. Curr Med Sci 2020; 40:1-8. [PMID: 32166659 DOI: 10.1007/s11596-020-2140-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 12/10/2019] [Indexed: 01/22/2023]
Abstract
Protein phosphatase 2A (PP2A) is a major serine/threonine phosphatase which participates in the regulation of multiple cellular processes. As a confirmed tumor suppressor, PP2A activity is downregulated in tumors and its re-activation can induce apoptosis of cancer cells. In the brains of Alzheimer's disease (AD) patients, decreased PP2A activity also plays a key role in promoting tau hyperphosphorylation and Aβ generation. In this review, we discussed compounds aiming at modulating PP2A activity in the treatment of cancer or AD. The upstream factors that inactivate PP2A in diseases have not been fully elucidated and further studies are needed. It will help for the refinement and development of novel and clinically tractable PP2A-targeted compounds or therapies for the treatment of tumor and AD.
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Affiliation(s)
- Hui Wei
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Hui-Liang Zhang
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Jia-Zhao Xie
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Dong-Li Meng
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Xiao-Chuan Wang
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Dan Ke
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
| | - Ji Zeng
- Department of Clinic Laboratory, Wuhan Fourth Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
| | - Rong Liu
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
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Skullcapflavone I suppresses proliferation of human lung cancer cells via down-regulating microRNA-21. Exp Mol Pathol 2019; 110:104285. [DOI: 10.1016/j.yexmp.2019.104285] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 07/01/2019] [Accepted: 07/10/2019] [Indexed: 11/19/2022]
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8
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Elgenaidi IS, Spiers JP. Regulation of the phosphoprotein phosphatase 2A system and its modulation during oxidative stress: A potential therapeutic target? Pharmacol Ther 2019; 198:68-89. [PMID: 30797822 DOI: 10.1016/j.pharmthera.2019.02.011] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 02/15/2019] [Indexed: 02/06/2023]
Abstract
Phosphoprotein phosphatases are of growing interest in the pathophysiology of many diseases and are often the neglected partner of protein kinases. One family member, PP2A, accounts for dephosphorylation of ~55-70% of all serine/threonine phosphosites. Interestingly, dysregulation of kinase signalling is a hallmark of many diseases in which an increase in oxidative stress is also noted. With this in mind, we assess the evidence to support oxidative stress-mediated regulation of the PP2A system In this article, we first present an overview of the PP2A system before providing an analysis of the regulation of PP2A by endogenous inhibitors, post translational modification, and miRNA. Next, a detailed critique of data implicating reactive oxygen species, ischaemia, ischaemia-reperfusion, and hypoxia in regulating the PP2A holoenzyme and associated regulators is presented. Finally, the pharmacological targeting of PP2A, its endogenous inhibitors, and enzymes responsible for its post-translational modification are covered. There is extensive evidence that oxidative stress modulates multiple components of the PP2A system, however, most of the data pertains to the catalytic subunit of PP2A. Irrespective of the underlying aetiology, free radical-mediated attenuation of PP2A activity is an emerging theme. However, in many instances, a dichotomy exists, which requires clarification and mechanistic insight. Nevertheless, this raises the possibility that pharmacological activation of PP2A, either through small molecule activators of PP2A or CIP2A/SET antagonists may be beneficial in modulating the cellular response to oxidative stress. A better understanding of which, will have wide ranging implications for cancer, heart disease and inflammatory conditions.
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Affiliation(s)
- I S Elgenaidi
- Department of Pharmacology and Therapeutics, Trinity College Dublin, Ireland
| | - J P Spiers
- Department of Pharmacology and Therapeutics, Trinity College Dublin, Ireland.
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9
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Nahari E, Razi M. Silymarin amplifies apoptosis in ectopic endometrial tissue in rats with endometriosis; implication on growth factor GDNF, ERK1/2 and Bcl-6b expression. Acta Histochem 2018; 120:757-767. [PMID: 30195499 DOI: 10.1016/j.acthis.2018.08.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 07/29/2018] [Accepted: 08/16/2018] [Indexed: 12/25/2022]
Abstract
The present prospective study was done to evaluate the effect of silymarin (SMN) on endometriotic-like legions establishment and growth in experimentally-induced endometriosis. For this purpose, the experimental endometriosis was induced in 12 rats and then the animals subdivided into endometriosis-sole and SMN (50 mg kg-1, orally)+endometriosis groups. Following 28 days, the legions establishment, size, Glial cell line-derived neurotrophic factor (GDNF), gfrα1, B Cell Lymphoma 6 (Bcl-6b), Bcl-2, extracellular regulator kinase (ERK1/2) expression ratios, angiogenesis, the apoptosis and fibrosis indices were investigated. The SMN significantly (P < 0.05) decreased the enometriotic-like legions establishment and size, decreased mRNA levels of GDNF, gfrα1, Bcl-6b and Bcl-2 and remarkably diminished GDNF, gfrα1, Bcl-6b and Bcl-2-positive cells distribution/mm2 of tissue versus endometriosis-sole group. The SMN + endometriosis group exhibited a significant (P < 0.05) enhancement in ERK1/2 expression and represented diminished vascularized area and increased apoptosis and fibrosis indices, as well. In conclusion, the SMN by down-regulating GDNF and its receptor gfrα1 expression inhibits GDNF-gfrα1 complex generation and consequently suppresses Bcl-6b expression. Moreover, the SMN by enhancing the ERK1/2 expression and by suppressing the Bcl-2 expression promotes the apoptosis pathway. Finally, the SMN by down-regulating the angiogenesis ratio accelerates apoptosis and consequently induces severe fibrosis in endometriotic-like legions.
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Affiliation(s)
- Elaheh Nahari
- Department of Biology, Tabriz Branch, Islamic Azad University, Tabriz, Iran
| | - Mazdak Razi
- Department of Basic Sciences, Faculty of Veterinary Medicine, P.O. BOC: 1177, Urmia University, Urmia, Iran.
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Dithiolethiones: a privileged pharmacophore for anticancer therapy and chemoprevention. Future Med Chem 2018; 10:1241-1260. [DOI: 10.4155/fmc-2017-0281] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Dithiolethiones are five-membered sulfur-containing cyclic scaffolds that exhibit antioxidative, anti-inflammatory, antithrombic and chemotherapeutic activities. Dithiolethiones display the chemopreventive and cytoprotective effects by activating the antioxidant response element and mounting the transcription of cytoprotective phase II enzymatic machinery. In addition, several classes of dithiolethiones efficiently modulate the activities of proteins that play crucial roles in normal and cancer cells, including glutathione S-transferase, cyclooxygenases and master regulator NF-κB. The present paper summarizes synthetic aspects, pharmacological potentials and biological attributes of dithiolethiones and its derivatives. Additionally, this review concludes with a discussion on how the current state-of-the-art technologies may help in defining a structure–activity relationship of dithiolethiones, thereby facilitating the design and synthesis of potent drug candidates.
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Gabriele E, Brambilla D, Ricci C, Regazzoni L, Taguchi K, Ferri N, Asai A, Sparatore A. New sulfurated derivatives of cinnamic acids and rosmaricine as inhibitors of STAT3 and NF-κB transcription factors. J Enzyme Inhib Med Chem 2017; 32:1012-1028. [PMID: 28738705 PMCID: PMC6009881 DOI: 10.1080/14756366.2017.1350658] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 06/30/2017] [Accepted: 06/30/2017] [Indexed: 12/30/2022] Open
Abstract
A set of new sulfurated drug hybrids, mainly derived from caffeic and ferulic acids and rosmaricine, has been synthesized and their ability to inhibit both STAT3 and NF-κB transcription factors have been evaluated. Results showed that most of the new hybrid compounds were able to strongly and selectively bind to STAT3, whereas the parent drugs were devoid of this ability at the tested concentrations. Some of them were also able to inhibit the NF-κB transcriptional activity in HCT-116 cell line and inhibited HCT-116 cell proliferation in vitro with IC50 in micromolar range, thus suggesting a potential anticancer activity. Taken together, our study described the identification of new derivatives with dual STAT3/NF-κB inhibitory activity, which may represent hit compounds for developing multi-target anticancer agents.
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Affiliation(s)
- Elena Gabriele
- Department of Pharmaceutical Sciences, Università degli Studi di Milano, Milano, Italy
| | - Dario Brambilla
- Department of Pharmaceutical Sciences, Università degli Studi di Milano, Milano, Italy
| | - Chiara Ricci
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, Milano, Italy
| | - Luca Regazzoni
- Department of Pharmaceutical Sciences, Università degli Studi di Milano, Milano, Italy
| | - Kyoko Taguchi
- Center for Drug Discovery, Graduate School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
| | - Nicola Ferri
- Department of Pharmaceutical and Pharmacological Sciences, Università degli Studi di Padova, Largo Egidio Meneghetti, Padova, Italy
| | - Akira Asai
- Center for Drug Discovery, Graduate School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
| | - Anna Sparatore
- Department of Pharmaceutical Sciences, Università degli Studi di Milano, Milano, Italy
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Ishii Y, Kuroda K, Matsushita K, Yokoo Y, Takasu S, Kijima A, Nohmi T, Ogawa K, Umemura T. Phosphorylation of protein phosphatase 2A facilitated an early stage of chemical carcinogenesis. Toxicol Appl Pharmacol 2017; 336:75-83. [PMID: 29054680 DOI: 10.1016/j.taap.2017.10.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 10/06/2017] [Accepted: 10/14/2017] [Indexed: 01/14/2023]
Abstract
Protein phosphatase 2A (PP2A) is a serine-threonine phosphatase that regulates cell signaling pathways. Its inactivation is correlated with tumor malignancy, possibly due to the effects on cell differentiation and malignant cell transformation. Therefore, it has been noted that PP2A could be a promising target for cancer therapy. In our previous study of the hepatocarcinogen estragole (ES), cell proliferation may be required to convert ES-specific DNA adducts to mutations. To explore the trigger for cell proliferation, gpt delta rats were administered ES by gavage at doses of 3, 30 and 300mg/kg/day for 4weeks. ES-induced cell proliferation and gene mutations were observed at only the high dose whereas ES-specific DNA adducts were detected in a dose-dependent manner. Western blot analyses revealed activation of the Akt and ERK pathways without activation of upstream regulators, such as c-Raf, PKC and, PI3K. Phosphorylation of the PP2A C subunit at Tyr307 was found along with phosphorylation of Src. The overall data might imply that PP2A inactivation is responsible for cell cycle progression through activation of the Akt and ERK pathways at high doses of ES. Based on γ-H2AX immunohistochemistry and Western blot analysis for Rad51 protein, the resultant mutation spectra showed large deletion mutations that might result from double strand breaks of DNA. Thus, it is likely that inactivation of PP2A resulted in acceleration and exacerbation of gene mutations. We conclude that PP2A might contribute to an early stage of chemical carcinogenesis, suggesting that PP2A could be a molecular target of primary cancer prevention.
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Affiliation(s)
- Yuji Ishii
- Division of Pathology, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan
| | - Ken Kuroda
- Division of Pathology, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan
| | - Kohei Matsushita
- Division of Pathology, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan
| | - Yuh Yokoo
- Division of Pathology, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan
| | - Shinji Takasu
- Division of Pathology, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan
| | - Aki Kijima
- Division of Pathology, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan
| | - Takehiko Nohmi
- Division of Genetics and Mutagenesis, National Institute of Health Science, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan
| | - Kumiko Ogawa
- Division of Pathology, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan
| | - Takashi Umemura
- Division of Pathology, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan; Faculty of Animal Science Technology, Yamazaki Gakuen University, 4-7-2 Minami-osawa, Hachioji, Tokyo 192-0364, Japan.
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EGFR-independent Elk1/CIP2A signalling mediates apoptotic effect of an erlotinib derivative TD52 in triple-negative breast cancer cells. Eur J Cancer 2017; 72:112-123. [DOI: 10.1016/j.ejca.2016.11.012] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2016] [Revised: 10/27/2016] [Accepted: 11/15/2016] [Indexed: 12/23/2022]
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14
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Liu CY, Hu MH, Hsu CJ, Huang CT, Wang DS, Tsai WC, Chen YT, Lee CH, Chu PY, Hsu CC, Chen MH, Shiau CW, Tseng LM, Chen KF. Lapatinib inhibits CIP2A/PP2A/p-Akt signaling and induces apoptosis in triple negative breast cancer cells. Oncotarget 2016; 7:9135-49. [PMID: 26824320 PMCID: PMC4891031 DOI: 10.18632/oncotarget.7035] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 01/19/2016] [Indexed: 12/14/2022] Open
Abstract
We tested the efficacy of lapatinib, a dual tyrosine kinase inhibitor which interrupts the HER2 and epidermal growth factor receptor (EGFR) pathways, in a panel of triple-negative breast cancer (TNBC) cells, and examined the drug mechanism. Lapatinib showed an anti-proliferative effect in HCC 1937, MDA-MB-468, and MDA-MB-231 cell lines. Lapatinib induced significant apoptosis and inhibited CIP2A and p-Akt in a dose and time-dependent manner in the three TNBC cell lines. Overexpression of CIP2A reduced lapatinib-induced apoptosis in MDA-MB-468 cells. In addition, lapatinib increased PP2A activity (in relation to CIP2A inhibition). Moreover, lapatinib-induced apoptosis and p-Akt downregulation was attenuated by PP2A antagonist okadaic acid. Furthermore, lapatinib indirectly decreased CIP2A transcription by disturbing the binding of Elk1 to the CIP2A promoter. Importantly, lapatinib showed anti-tumor activity in mice bearing MDA-MB-468 xenograft tumors, and suppressed CIP2A as well as p-Akt in these xenografted tumors. In summary, inhibition of CIP2A determines the effects of lapatinib-induced apoptosis in TNBC cells. In addition to being a dual tyrosine kinase inhibitor of HER2 and EGFR, lapatinib also inhibits CIP2A/PP2A/p-Akt signaling in TNBC cells.
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Affiliation(s)
- Chun-Yu Liu
- Division of Medical Oncology, Department of Oncology, Taipei Veterans General Hospital, Taipei, Taiwan.,School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Ming-Hung Hu
- Division of Hematology and Oncology, Department of Medicine, Cardinal Tien Hospital, New Taipei City, Taiwan.,School of Medicine, Fu Jen Catholic University, New Taipei City, Taiwan
| | - Chia-Jung Hsu
- Division of Medical Oncology, Department of Oncology, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Chun-Teng Huang
- School of Medicine, National Yang-Ming University, Taipei, Taiwan.,Division of Hematology & Oncology, Department of Medicine, Yang-Ming Branch of Taipei City Hospital, Taipei, Taiwan
| | - Duen-Shian Wang
- Division of Medical Oncology, Department of Oncology, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Wen-Chun Tsai
- Division of Medical Oncology, Department of Oncology, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Yi-Ting Chen
- Division of Medical Oncology, Department of Oncology, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Chia-Han Lee
- Division of Medical Oncology, Department of Oncology, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Pei-Yi Chu
- Department of Pathology, Show Chwan Memorial Hospital, Changhua City, Taiwan
| | - Chia-Chi Hsu
- Institute of Pharmacology, National Yang-Ming University, Taipei, Taiwan
| | - Ming-Huang Chen
- Division of Medical Oncology, Department of Oncology, Taipei Veterans General Hospital, Taipei, Taiwan.,School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Chung-Wai Shiau
- Institute of Biopharmaceutical Sciences, National Yang-Ming University, Taipei, Taiwan
| | - Ling-Ming Tseng
- School of Medicine, National Yang-Ming University, Taipei, Taiwan.,Department of Surgery, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Kuen-Feng Chen
- Department of Medical Research, National Taiwan University Hospital, Taipei, Taiwan.,National Taiwan University College of Medicine, Taipei, Taiwan
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15
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Grech G, Baldacchino S, Saliba C, Grixti MP, Gauci R, Petroni V, Fenech AG, Scerri C. Deregulation of the protein phosphatase 2A, PP2A in cancer: complexity and therapeutic options. Tumour Biol 2016; 37:11691-11700. [PMID: 27444275 DOI: 10.1007/s13277-016-5145-4] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 07/11/2016] [Indexed: 01/26/2023] Open
Abstract
The complexity of the phosphatase, PP2A, is being unravelled and current research is increasingly providing information on the association of deregulated PP2A function with cancer initiation and progression. It has been reported that decreased activity of PP2A is a recurrent observation in many types of cancer, including colorectal and breast cancer (Baldacchino et al. EPMA J. 5:3, 2014; Cristobal et al. Mol Cancer Ther. 13:938-947, 2014). Since deregulation of PP2A and its regulatory subunits is a common event in cancer, PP2A is a potential target for therapy (Baldacchino et al. EPMA J. 5:3, 2014). In this review, the structural components of the PP2A complex are described, giving an in depth overview of the diversity of regulatory subunits. Regulation of the active PP2A trimeric complex, through phosphorylation and methylation, can be targeted using known compounds, to reactivate the complex. The endogenous inhibitors of the PP2A complex are highly deregulated in cancer, representing cases that are eligible to PP2A-activating drugs. Pharmacological opportunities to target low PP2A activity are available and preclinical data support the efficacy of these drugs, but clinical trials are lacking. We highlight the importance of PP2A deregulation in cancer and the current trends in targeting the phosphatase.
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Affiliation(s)
- Godfrey Grech
- Department of Pathology, Faculty of Medicine & Surgery, Medical School, University of Malta, Msida, MSD2090, Malta.
| | - Shawn Baldacchino
- Department of Pathology, Faculty of Medicine & Surgery, Medical School, University of Malta, Msida, MSD2090, Malta
| | - Christian Saliba
- Centre for Molecular Medicine and Biobanking, University of Malta, Msida, Malta
| | - Maria Pia Grixti
- Department of Pathology, Faculty of Medicine & Surgery, Medical School, University of Malta, Msida, MSD2090, Malta
| | - Robert Gauci
- Department of Pathology, Faculty of Medicine & Surgery, Medical School, University of Malta, Msida, MSD2090, Malta
| | - Vanessa Petroni
- Department of Anatomy, Faculty of Medicine & Surgery, University of Malta, Msida, Malta
| | - Anthony G Fenech
- Department of Clinical Pharmacology & Therapeutics, Faculty of Medicine & Surgery, University of Malta, Msida, Malta
| | - Christian Scerri
- Department of Physiology and Biochemistry, Faculty of Medicine & Surgery, University of Malta, Msida, Malta.,Molecular Genetics Clinic, Mater Dei Hospital, Msida, Malta
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16
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Zeng LP, Hu ZM, Li K, Xia K. miR-222 attenuates cisplatin-induced cell death by targeting the PPP2R2A/Akt/mTOR Axis in bladder cancer cells. J Cell Mol Med 2016; 20:559-67. [PMID: 26800397 PMCID: PMC4759461 DOI: 10.1111/jcmm.12760] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 11/13/2015] [Indexed: 12/15/2022] Open
Abstract
Increased miR-222 levels are associated with a poor prognosis in patients with bladder cancer. However, the role of miR-222 remains unclear. In the present study, we found that miR-222 enhanced the proliferation of both the T24 and the 5637 bladder cancer cell lines. Overexpression of miR-222 attenuated cisplatin-induced cell death in bladder cancer cells. miR-222 activated the Akt/mTOR pathway and inhibited cisplatin-induced autophagy in bladder cancer cells by directly targeting protein phosphatase 2A subunit B (PPP2R2A). Blocking the activation of Akt with LY294002 or mTOR with rapamycin significantly prevented miR-222-induced proliferation and restored the sensitivity of bladder cancer cells to cisplatin. These findings demonstrate that miR-222 modulates the PPP2R2A/Akt/mTOR axis and thus plays a critical role in regulating proliferation and chemotherapeutic drug resistance. Therefore, miR-222 may be a novel therapeutic target for bladder cancer.
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Affiliation(s)
- Li-Ping Zeng
- The State Key Laboratory of Medical Genetics, Central South University, Changsha, Hunan, China
| | - Zheng-Mao Hu
- The State Key Laboratory of Medical Genetics, Central South University, Changsha, Hunan, China
| | - Kai Li
- The Clinical Laboratory of No.261 Hospital of the People's Liberation Army, Beijing, China
| | - Kun Xia
- The State Key Laboratory of Medical Genetics, Central South University, Changsha, Hunan, China
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Chen Y, Wang S, Fu X, Zhou W, Hong W, Zou D, Li X, Liu J, Ran P, Li B. tert-Butylhydroquinone mobilizes intracellular-bound zinc to stabilize Nrf2 through inhibiting phosphatase activity. Am J Physiol Cell Physiol 2015; 309:C148-58. [DOI: 10.1152/ajpcell.00031.2015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 05/05/2015] [Indexed: 01/06/2023]
Abstract
The nuclear factor erythroid 2-related factor 2 (Nrf2) is required to combat increases in oxidative stress. The chemical compound tert-butylhydroquinone (tBHQ) can downregulate Kelch-like ECH-associated protein 1 (Keap1), a repressor of Nrf2, thus maintaining the stability of Nrf2. tBHQ can also increase intracellular “free” zinc in human bronchial epithelial (16HBE) cells. We aim to investigate whether the intracellular free zinc change plays a role in Nrf2 activation. tBHQ exposure dose-dependently increases intracellular free zinc concentrations within 30 min in 16HBE cells by mobilizing intracellular zinc pools. Active Nrf2 and the antioxidant enzyme heme oxygenase-1 (HO-1) increase at 3 h after tBHQ treatment. Chelating intracellular free zinc with tetrakis-(2-pyridylmethyl)ethylenediamine (TPEN) during tBHQ exposure partially abrogates the tBHQ-induced activation of Nrf2 and HO-1 expression, while Keap1 is further decreased. These results indicate that tBHQ-induced stability of Nrf2 is associated with the intracellular free zinc level. Because the activated Nrf2 is phosphorylated, the serine/threonine protein phosphatase activity, which is known to be inhibited by zinc, is assayed. The results showed that tBHQ treatment can suppress cellular protein phosphatase-2A (PP2A) and protein phosphatase-2C (PP2C) activity, which can be abrogated by adding TPEN. This finding is verified in a cell-free protein extract experiment by supplying zinc or by chelating zinc with TPEN. These results provide a novel mechanistic insight into Nrf2 activation in antioxidant enzyme induction involving zinc signaling. The increase of intracellular free zinc may be one mechanism for Nrf2 activation. The inhibition of PP2A and PP2C activity may be involved in Nrf2 phosphorylation modulation.
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Affiliation(s)
- Yunfang Chen
- Experiment Medical Research Center, Guangzhou Medical University, Guangzhou, China
| | - Sheng Wang
- National key Laboratory of Respiratory Diseases, Guangzhou Medical University, Guangzhou, China
| | - Xin Fu
- Experiment Medical Research Center, Guangzhou Medical University, Guangzhou, China
| | - Wenqu Zhou
- Experiment Medical Research Center, Guangzhou Medical University, Guangzhou, China
| | - Wei Hong
- Experiment Medical Research Center, Guangzhou Medical University, Guangzhou, China
| | - Dongting Zou
- Experiment Medical Research Center, Guangzhou Medical University, Guangzhou, China
| | - Xichong Li
- Experiment Medical Research Center, Guangzhou Medical University, Guangzhou, China
| | - Jinbao Liu
- Department of Pathophysiology, Guangzhou Medical University, Guangzhou, China; and
| | - Pixin Ran
- National key Laboratory of Respiratory Diseases, Guangzhou Medical University, Guangzhou, China
| | - Bing Li
- Experiment Medical Research Center, Guangzhou Medical University, Guangzhou, China
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18
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Kim EJ, Kim HJ, Park MK, Kang GJ, Byun HJ, Lee H, Lee CH. Cardamonin Suppresses TGF-β1-Induced Epithelial Mesenchymal Transition via Restoring Protein Phosphatase 2A Expression. Biomol Ther (Seoul) 2015; 23:141-8. [PMID: 25767682 PMCID: PMC4354315 DOI: 10.4062/biomolther.2014.117] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Revised: 12/12/2014] [Accepted: 12/16/2014] [Indexed: 12/20/2022] Open
Abstract
Epithelial mesenchymal transition (EMT) is the first step in metastasis and implicated in the phenotype of cancer stem cells. Therefore, understanding and controlling EMT, are essential to the prevention and cure of metastasis. In the present study, we examined, by Western blot, reverse transcription polymerase chain reaction (RT-PCR), and confocal microscopy, the effects of cardamonin (CDN) on transforming growth factor-β1 (TGF-β1)-induced EMT of A549 lung adenocarcinoma cell lines. TGF-β1 induced expression of N-cadherin and decreased expression of E-cadherin. CDN suppressed N-cadherin expression and restored E-cadherin expression. Further, TGF-β1 induced migration and invasion of A549 cancer cells, which was suppressed by CDN. TGF-β1 induced c-Jun N-terminal kinase (JNK) activation during EMT, but CDN blocked it. Protein serine/threonine phosphatase 2A (PP2A) expression in A549 cancer cells was reduced by TGF-β1 but CDN restored it. The overall data suggested that CDN suppresses TGF-β1-induced EMT via PP2A restoration, making it a potential new drug candidate that controls metastasis.
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Affiliation(s)
- Eun Ji Kim
- BK21PLUS R-FIND Team, College of Pharmacy, Dongguk University, Seoul 100-715, Republic of Korea
| | - Hyun Ji Kim
- BK21PLUS R-FIND Team, College of Pharmacy, Dongguk University, Seoul 100-715, Republic of Korea
| | - Mi Kyung Park
- BK21PLUS R-FIND Team, College of Pharmacy, Dongguk University, Seoul 100-715, Republic of Korea
| | - Gyeung Jin Kang
- BK21PLUS R-FIND Team, College of Pharmacy, Dongguk University, Seoul 100-715, Republic of Korea
| | - Hyun Jung Byun
- BK21PLUS R-FIND Team, College of Pharmacy, Dongguk University, Seoul 100-715, Republic of Korea
| | - Ho Lee
- National Cancer Center, Goyang 410-769, Republic of Korea
| | - Chang Hoon Lee
- BK21PLUS R-FIND Team, College of Pharmacy, Dongguk University, Seoul 100-715, Republic of Korea
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19
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Abstract
Pharmacological concentrations of H2S donors inhibit some T cell functions by inhibiting mitochondrial function, but evidence is also emerging that H2S at physiological concentrations produced via chemical sources and endogenously is a positive physiological mediator of T cell function. Expression of the H2S biosynthetic enzymes cystathionine γ-lyase (CSE) and cystathionine β-synthase (CBS) is induced in response to T cell receptor signaling. Inhibiting the induction of these enzymes limits T cell activation and proliferation, which can be overcome by exposure to exogenous H2S at submicromolar concentrations. Exogenous H2S at physiological concentrations increases the ability of T cells to form an immunological synapse by altering cytoskeletal actin dynamics and increasing the reorientation of the microtubule-organizing center. Downstream, H2S enhances T cell receptor-dependent induction of CD69, CD25, and Interleukin-2 (IL-2) gene expression. The T cell stimulatory activity of H2S is enhanced under hypoxic conditions that limit its oxidative metabolism by mitochondrial and nonenzymatic processes. Studies of the receptor CD47 have revealed the first endogenous inhibitory signaling pathway that regulates H2S signaling in T cells. Binding of the secreted protein thrombospondin-1 to CD47 elicits signals that block the stimulatory activity of exogenous H2S on T cell activation and limit the induction of CSE and CBS gene expression. CD47 signaling thereby inhibits T cell receptor-mediated T cell activation.
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20
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The single N-glycan deletion mutant of soluble ErbB3 protein attenuates heregulin β1-induced tumor progression by blocking of the HIF-1 and Nrf2 pathway. Biochem Biophys Res Commun 2014; 454:364-8. [DOI: 10.1016/j.bbrc.2014.10.086] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 10/18/2014] [Indexed: 11/18/2022]
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21
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Tamoxifen induces apoptosis through cancerous inhibitor of protein phosphatase 2A-dependent phospho-Akt inactivation in estrogen receptor-negative human breast cancer cells. Breast Cancer Res 2014; 16:431. [PMID: 25228280 PMCID: PMC4303112 DOI: 10.1186/s13058-014-0431-9] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Accepted: 08/21/2014] [Indexed: 11/11/2022] Open
Abstract
Introduction Tamoxifen, a selective estrogen receptor (ER) modulator, may affect cancer cell survival through mechanisms other than ER antagonism. In the present study, we tested the efficacy of tamoxifen in a panel of ER-negative breast cancer cell lines and examined the drug mechanism. Methods In total, five ER-negative breast cancer cell lines (HCC-1937, MDA-MB-231, MDA-MB-468, MDA-MB-453 and SK-BR-3) were used for in vitro studies. Cellular apoptosis was examined by flow cytometry and Western blot analysis. Signal transduction pathways in cells were assessed by Western blot analysis. The in vivo efficacy of tamoxifen was tested in xenograft nude mice. Results Tamoxifen induced significant apoptosis in MDA-MB-231, MDA-MB-468, MDA-MB-453 and SK-BR-3 cells, but not in HCC-1937 cells. Tamoxifen-induced apoptosis was associated with inhibition of cancerous inhibitor of protein phosphatase 2A (CIP2A) and phospho-Akt (p-Akt) in a dose-dependent manner. Ectopic expression of either CIP2A or Akt protected MDA-MB-231 cells from tamoxifen-induced apoptosis. In addition, tamoxifen increased protein phosphatase 2A (PP2A) activity, and tamoxifen-induced apoptosis was attenuated by the PP2A antagonist okadaic acid in the sensitive cell lines, but not in resistant HCC-1937 cells. Moreover, silencing CIP2A by small interfering RNA sensitized HCC-1937 cells to tamoxifen-induced apoptosis. Furthermore, tamoxifen regulated CIP2A protein expression by downregulating CIP2A mRNA. Importantly, tamoxifen inhibited the in vivo growth of MDA-MB-468 xenograft tumors in association with CIP2A downregulation, whereas tamoxifen had no significant effect on CIP2A expression and anti-tumor growth in HCC-1937 tumors. Conclusions Inhibition of CIP2A determines the effects of tamoxifen-induced apoptosis in ER-negative breast cancer cells. Our data suggest a novel “off-target“ mechanism of tamoxifen and suggest that CIP2A/PP2A/p-Akt signaling may be a feasible anti-cancer pathway. Electronic supplementary material The online version of this article (doi:10.1186/s13058-014-0431-9) contains supplementary material, which is available to authorized users.
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22
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Yuan Y, Du W, Wang Y, Xu C, Wang J, Zhang Y, Wang H, Ju J, Zhao L, Wang Z, Lu Y, Cai B, Pan Z. Suppression of AKT expression by miR-153 produced anti-tumor activity in lung cancer. Int J Cancer 2014; 136:1333-40. [PMID: 25066607 DOI: 10.1002/ijc.29103] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2013] [Accepted: 07/22/2014] [Indexed: 12/21/2022]
Abstract
Lung cancer is one of the leading causes of cancer death worldwide. microRNAs have been shown to be a novel class of regulators in lung cancer. Here, we explored the role of miR-153 in the pathogenesis of lung cancer and its therapeutic potential. miR-153 was significantly decreased in lung cancer tissues than the adjacent tissues. The protein and mRNA levels of protein kinase B (AKT), which were shown to promote tumor growth, were both increased in lung cancer tissues than adjacent tissues. Overexpression of miR-153 significantly inhibited AKT protein expression, which were abrogated by co-transfection of AMO-153, the specific inhibitor of miR-153. Luciferase assay showed that transfection of miR-153 markedly suppressed the fluorescent intensity of chimeric vectors carrying the 3'UTR of AKT1, while produced no effect on the mutant construct, indicating that AKT is regulated by miR-153. Overexpression of miR-153 significantly inhibited the proliferation and migration, and promoted apoptosis of cultured lung cancer cells in vitro, and suppressed the growth of xenograft tumors in vivo. Interestingly, lung cancer cells with lower endogenous miR-153 expression are more sensitive to ectopic overexpressed miR-153. The IC50 of miR-153 on lung cancer cells is positive correlated with the endogenous miR-153 level, while negative correlated with AKT level. Knockdown of AKT expression suppressed lung cancer cell proliferation. In summary, miR-153 exerted anti-tumor activity in lung cancer by targeting on AKT. The sensitivity of lung cancer cells to miR-153 is determined by its endogenous miR-153 level.
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Affiliation(s)
- Ye Yuan
- Department of Pharmacology, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education; State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Harbin Medical University, Harbin, Heilongjiang, People's Republic of China
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Liu H, Liu YZ, Zhang F, Wang HS, Zhang G, Zhou BH, Zuo YL, Cai SH, Bu XZ, Du J. Identification of potential pathways involved in the induction of cell cycle arrest and apoptosis by a new 4-arylidene curcumin analogue T63 in lung cancer cells: a comparative proteomic analysis. MOLECULAR BIOSYSTEMS 2014; 10:1320-31. [DOI: 10.1039/c3mb70553f] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Abstract
PP2A is a family of mammalian serine/threonine phosphatases that is involved in the control of many cellular functions including protein synthesis, cellular signaling, cell cycle determination, apoptosis, metabolism, and stress responses through the negative regulation of signaling pathways initiated by protein kinases. Rapid progress is being made in the understanding of PP2A complex and its functions. Emerging studies have correlated changes in PP2A with human diseases, especially cancer. PP2A is comprised of 3 subunits: a catalytic subunit, a scaffolding subunit, and a regulatory subunit. The alternations of the subunits have been shown to be in association with many human malignancies. Therapeutic agents targeting PP2A inhibitors or activating PP2A directly have shed light on the therapy of cancers. This review focuses on PP2A structure, cancer-associated mutations, and the targeting of PP2A-related molecules to restore or reactivate PP2A in anticancer therapy, especially in digestive system cancer therapy.
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25
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Arrouss I, Nemati F, Roncal F, Wislez M, Dorgham K, Vallerand D, Rabbe N, Karboul N, Carlotti F, Bravo J, Mazier D, Decaudin D, Rebollo A. Specific targeting of caspase-9/PP2A interaction as potential new anti-cancer therapy. PLoS One 2013; 8:e60816. [PMID: 23637769 PMCID: PMC3634037 DOI: 10.1371/journal.pone.0060816] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 03/03/2013] [Indexed: 01/02/2023] Open
Abstract
PURPOSE PP2A is a serine/threonine phosphatase critical to physiological processes, including apoptosis. Cell penetrating peptides are molecules that can translocate into cells without causing membrane damage. Our goal was to develop cell-penetrating fusion peptides specifically designed to disrupt the caspase-9/PP2A interaction and evaluate their therapeutic potential in vitro and in vivo. EXPERIMENTAL DESIGN We generated a peptide containing a penetrating sequence associated to the interaction motif between human caspase-9 and PP2A (DPT-C9h), in order to target their association. Using tumour cell lines, primary human cells and primary human breast cancer (BC) xenografts, we investigated the capacity of DPT-C9h to provoke apoptosis in vitro and inhibition of tumour growth (TGI) in vivo. DPT-C9h was intraperitoneally administered at doses from 1 to 25 mg/kg/day for 5 weeks. Relative Tumour Volume (RTV) was calculated. RESULTS We demonstrated that DPT-C9h specifically target caspase-9/PP2A interaction in vitro and in vivo and induced caspase-9-dependent apoptosis in cancer cell lines. DPT-C9h also induced significant TGI in BC xenografts models. The mouse-specific peptide DPT-C9 also induced TGI in lung (K-Ras model) and breast cancer (PyMT) models. DPT-C9h has a specific effect on transformed B cells isolated from chronic lymphocytic leukemia patients without any effect on primary healthy cells. Finally, neither toxicity nor immunogenic responses were observed. CONCLUSION Using the cell-penetrating peptides blocking caspase-9/PP2A interactions, we have demonstrated that DPT-C9h had a strong therapeutic effect in vitro and in vivo in mouse models of tumour progression.
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Affiliation(s)
- Issam Arrouss
- Inserm UMRS 945, Hôpital Pitié Salpêtrière, Université Pierre et Marie Curie, Paris, France
| | - Fariba Nemati
- Laboratory of Preclinical Investigation, Translational Research Department, Institut Curie, Paris, France
| | - Fernando Roncal
- Centro Nacional de Biotecnologia, Campus de Cantoblanco, Universidad Autónoma de Madrid, Madrid, Spain
| | - Marie Wislez
- URF Pierre et Marie Curie, Hôpital Tenon, Paris, France
| | - Karim Dorgham
- Inserm UMRS 945, Hôpital Pitié Salpêtrière, Université Pierre et Marie Curie, Paris, France
| | - David Vallerand
- Laboratory of Preclinical Investigation, Translational Research Department, Institut Curie, Paris, France
| | | | - Narjesse Karboul
- Laboratory of Preclinical Investigation, Translational Research Department, Institut Curie, Paris, France
| | - Françoise Carlotti
- Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, The Netherlands
| | - Jeronimo Bravo
- Instituto de Biomedicina de Valencia, Consejo Superior de Investigaciones Cientificas, Valencia, Spain
| | - Dominique Mazier
- Inserm UMRS 945, Hôpital Pitié Salpêtrière, Université Pierre et Marie Curie, Paris, France
| | - Didier Decaudin
- Laboratory of Preclinical Investigation, Translational Research Department, Institut Curie, Paris, France
- Department of Medical Oncology, Institut Curie, Paris, France
| | - Angelita Rebollo
- Inserm UMRS 945, Hôpital Pitié Salpêtrière, Université Pierre et Marie Curie, Paris, France
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26
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Abstract
Protein phosphatases of the type 2A family (PP2A) represent a major fraction of cellular Ser/Thr phosphatase activity in any given human tissue. In this review, we describe how the holoenzymic nature of PP2A and the existence of several distinct PP2A composing subunits allow for the generation of multiple structurally and functionally different PP2A complexes, explaining why PP2A is involved in the regulation of so many diverse cell biological and physiological processes. Moreover, in human disease, most notably in several cancers and Alzheimer's Disease, PP2A expression and/or activity have been found significantly decreased, underscoring its important functions as a major tumor suppressor and tau phosphatase. Hence, several recent preclinical studies have demonstrated that pharmacological restoration of PP2A activity, as well as pharmacological PP2A inhibition, under certain conditions, may be of significant future therapeutic value.
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27
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Sen S, Kawahara B, Chaudhuri G. Maintenance of higher H₂O₂ levels, and its mechanism of action to induce growth in breast cancer cells: important roles of bioactive catalase and PP2A. Free Radic Biol Med 2012; 53:1541-51. [PMID: 22749807 DOI: 10.1016/j.freeradbiomed.2012.06.030] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Revised: 06/19/2012] [Accepted: 06/20/2012] [Indexed: 01/01/2023]
Abstract
We assessed the catalase bioactivity and hydrogen peroxide (H₂O₂) production rate in human breast cancer (HBC) cell lines and compared these with normal human breast epithelial (HBE) cells. We observed that the bioactivity of catalase was decreased in HBC cells when compared with HBE cells. This was also accompanied by an increase in H₂O₂ steady-state levels in HBC cells. Silencing the catalase gene led to a further increase in the steady-state level of H₂O₂ which was also accompanied by an increase in growth rate of HBC cells. Catalase activity was up regulated on treatment with superoxide (O₂⁻) scavengers such as pegylated SOD (PEG-SOD, indicating inhibition of catalase by the increased O₂⁻ produced by HBC cells. Transfection of either catalase or glutathione peroxidase to HBC cells decreased intracellular H₂O₂ levels and led to apoptosis of these cells. The H₂O₂ produced by HBC cells inhibited PP2A activity accompanied by increased phosphorylation of Akt and ERK1/2. The importance of catalase bioactivity in breast cancer was further confirmed as its bioactivity was also decreased in human breast cancer tissues when compared to normal breast tissues. We conclude that inhibition of catalase bioactivity by O₂⁻ leads to an increase in steady-state levels of H₂O₂ in HBC cells, which in turn inhibits PP2A activity, leading to phosphorylation of ERK 1/2 and Akt and resulting in HBC cell proliferation.
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Affiliation(s)
- Suvajit Sen
- Department of Obstetrics and Gynecology, David Geffen School of Medicine at University of California at Los Angeles, Los Angeles, CA 90095-6928, USA.
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Ridnour LA, Barasch KM, Windhausen AN, Dorsey TH, Lizardo MM, Yfantis HG, Lee DH, Switzer CH, Cheng RYS, Heinecke JL, Brueggemann E, Hines HB, Khanna C, Glynn SA, Ambs S, Wink DA. Nitric oxide synthase and breast cancer: role of TIMP-1 in NO-mediated Akt activation. PLoS One 2012; 7:e44081. [PMID: 22957045 PMCID: PMC3434220 DOI: 10.1371/journal.pone.0044081] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Accepted: 07/31/2012] [Indexed: 01/14/2023] Open
Abstract
Prediction of therapeutic response and cancer patient survival can be improved by the identification of molecular markers including tumor Akt status. A direct correlation between NOS2 expression and elevated Akt phosphorylation status has been observed in breast tumors. Tissue inhibitor matrix metalloproteinase-1 (TIMP-1) has been proposed to exert oncogenic properties through CD63 cell surface receptor pathway initiation of pro-survival PI3k/Akt signaling. We employed immunohistochemistry to examine the influence of TIMP-1 on the functional relationship between NOS2 and phosphorylated Akt in breast tumors and found that NOS2-associated Akt phosphorylation was significantly increased in tumors expressing high TIMP-1, indicating that TIMP-1 may further enhance NO-induced Akt pathway activation. Moreover, TIMP-1 silencing by antisense technology blocked NO-induced PI3k/Akt/BAD phosphorylation in cultured MDA-MB-231 human breast cancer cells. TIMP-1 protein nitration and TIMP-1/CD63 co-immunoprecipitation was observed at NO concentrations that induced PI3k/Akt/BAD pro-survival signaling. In the survival analysis, elevated tumor TIMP-1 predicted poor patient survival. This association appears to be mainly restricted to tumors with high NOS2 protein. In contrast, TIMP-1 did not predict poor survival in patient tumors with low NOS2 expression. In summary, our findings suggest that tumors with high TIMP-1 and NOS2 behave more aggressively by mechanisms that favor Akt pathway activation.
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Affiliation(s)
- Lisa A. Ridnour
- Radiation Biology Branch, National Cancer Institute, Bethesda, Maryland, United States of America
- * E-mail: (LAR); (DAW)
| | - Kimberly M. Barasch
- Radiation Biology Branch, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Alisha N. Windhausen
- Radiation Biology Branch, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Tiffany H. Dorsey
- Laboratory of Human Carcinogenesis, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Michael M. Lizardo
- Tumor and Metastasis Biology Section, Pediatric Oncology Branch, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Harris G. Yfantis
- Pathology and Laboratory Medicine, Baltimore Veterans Affairs Medical Center, Baltimore, Maryland, United States of America
| | - Dong H. Lee
- Pathology and Laboratory Medicine, Baltimore Veterans Affairs Medical Center, Baltimore, Maryland, United States of America
| | - Christopher H. Switzer
- Radiation Biology Branch, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Robert Y. S. Cheng
- Radiation Biology Branch, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Julie L. Heinecke
- Radiation Biology Branch, National Cancer Institute, Bethesda, Maryland, United States of America
| | | | - Harry B. Hines
- USAMRIID, Fort Detrick, Maryland, United States of America
| | - Chand Khanna
- Tumor and Metastasis Biology Section, Pediatric Oncology Branch, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Sharon A. Glynn
- Radiation Biology Branch, National Cancer Institute, Bethesda, Maryland, United States of America
- Laboratory of Human Carcinogenesis, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Stefan Ambs
- Laboratory of Human Carcinogenesis, National Cancer Institute, Bethesda, Maryland, United States of America
| | - David A. Wink
- Radiation Biology Branch, National Cancer Institute, Bethesda, Maryland, United States of America
- * E-mail: (LAR); (DAW)
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29
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Switzer CH, Cheng RYS, Ridnour LA, Murray MC, Tazzari V, Sparatore A, Del Soldato P, Hines HB, Glynn SA, Ambs S, Wink DA. Dithiolethiones inhibit NF-κB activity via covalent modification in human estrogen receptor-negative breast cancer. Cancer Res 2012; 72:2394-404. [PMID: 22436383 DOI: 10.1158/0008-5472.can-11-3115] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The NF-κB transcription factor family influences breast cancer outcomes by regulating genes involved in tumor progression, angiogenesis, and metastasis. Dithiolethiones, a class of naturally occurring compounds with cancer chemoprevention effects that have become clinically available, have been found to inhibit NF-κB activity. However, the mechanism of this inhibition has not been identified, and the influence of dithiolethines on NF-κB pathway in breast cancer cells has not been examined. Here, we investigated the chemical and biochemical effects of dithiolethione on NF-κB and downstream effector molecules in estrogen receptor-negative breast cancer cells and murine tumor xenografts. The dithiolethiones ACS-1 and ACS-2 inhibited NF-κB transcriptional activity. Interestingly, this inhibition was not due to H(2)S release or protein phosphatase 2A activation, which are key properties of dithiolethiones, but occurred via a covalent reaction with the NF-κB p50 and p65 subunits to inhibit DNA binding. Dithiolethione-mediated inhibition of NF-κB-regulated genes resulted in the inhibition of interleukin (IL)-6, IL-8, urokinase-type plasminogen activator, and VEGF production. ACS-1 also inhibited matrix metalloproteinase-9 activity, cellular migration, and invasion, and ACS-2 reduced tumor burden and resulted in increased tumor host interactions. Together, our findings suggest that dithiolethiones show potential clinical use for estrogen negative breast cancer as a chemotherapeutic or adjuvant therapy.
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Switzer CH, Glynn SA, Ridnour LA, Cheng RYS, Vitek MP, Ambs S, Wink DA. Nitric oxide and protein phosphatase 2A provide novel therapeutic opportunities in ER-negative breast cancer. Trends Pharmacol Sci 2011; 32:644-51. [PMID: 21893353 PMCID: PMC3380363 DOI: 10.1016/j.tips.2011.07.001] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2011] [Revised: 06/24/2011] [Accepted: 07/06/2011] [Indexed: 12/16/2022]
Abstract
Basal-like breast cancer is an aggressive disease with limited therapeutic options because these tumors frequently express the 'triple-negative' phenotype. We have recently reported that inducible nitric oxide synthase (NOS2) is a strong predictor of survival in patients with estrogen receptor negative [ER(-)] breast cancer, and that NOS2 expression is correlated with a basal-like phenotype. Recent reports also describe the pro-tumor effects of NO in breast and many other types of cancer. NO promotes cancer progression by activating several oncogenic signaling pathways such as extracellular signal-regulated kinases (ERK)-1/2, phosphoinositide 3-kinases (PI3K)/Akt, and c-Myc. Protein phosphatase 2A (PP2A) is a tumor suppressor that negatively regulates the same cancer-related signaling pathways that are activated by NO. PP2A activity is suppressed in tumor cells, but potential pharmacological agents have recently been described to increase PP2A activity in ER(-) breast cancer cells. We examine here the various functions of NO and PP2A in breast cancer and propose a novel mechanism by which activation of PP2A antagonizes NO signaling that promotes ER(-) breast cancer.
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Affiliation(s)
- Christopher H Switzer
- Radiation Biology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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31
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Kim W, Youn H, Seong KM, Yang HJ, Yun YJ, Kwon T, Kim YH, Lee JY, Jin YW, Youn B. PIM1-activated PRAS40 regulates radioresistance in non-small cell lung cancer cells through interplay with FOXO3a, 14-3-3 and protein phosphatases. Radiat Res 2011; 176:539-52. [PMID: 21910584 DOI: 10.1667/rr2609.1] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Resistance of cancer cells to ionizing radiation plays an important role in the clinical setting of lung cancer treatment. To date, however, the exact molecular mechanism of radiosensitivity has not been well explained. In this study, we compared radioresistance in two types of non-small cell lung cancer (NSCLC) cells, NCI-H460 and A549, and investigated the signaling pathways that confer radioresistance. In radioresistant cells, exposure to radiation led to overexpression of PIM1 and reduction of protein phosphatases (PP2A and PP5), which induced translocation of PIM1 into the nucleus. Increased nuclear PIM1 phosphorylated PRAS40. Consequently, pPRAS40 made a trimeric complex with 14-3-3 and AKT-activated pFOXO3a, which then moved rapidly to the cytoplasm. Cytoplasmic retention of FOXO3a was associated with downregulation of proapoptotic genes and possibly radioresistance. On the other hand, no suppressive effect of radiation on protein phosphatases was detected and, concomitantly, protein phosphatases downregulated PIM1 in radiosensitive cells. In this setting, PIM1-activated pPRAS40, AKT-activated pFOXO3a, and their complex formation with 14-3-3 could be key regulators of the radiation-induced radioresistance in NSCLC cells.
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Affiliation(s)
- Wanyeon Kim
- College of Natural Sciences, Department of Biological Sciences, Pusan National University, Busan, South Korea
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32
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Qi Z, Yang W, Liu Y, Cui T, Gao H, Duan C, Lu L, Zhao C, Zhao H, Yang H. Loss of PINK1 function decreases PP2A activity and promotes autophagy in dopaminergic cells and a murine model. Neurochem Int 2011; 59:572-81. [PMID: 21672589 DOI: 10.1016/j.neuint.2011.03.023] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2010] [Revised: 03/15/2011] [Accepted: 03/26/2011] [Indexed: 10/18/2022]
Abstract
Parkinson's disease (PD) is the most common neurodegenerative movement disorder. Mutations in PTEN-induced kinase 1 (PINK1) are a frequent cause of recessive PD. Autophagy, a pathway for clearance of protein aggregates or impaired organelles, is a newly identified mechanism for PD development. However, it is still unclear what molecules regulate autophagy in PINK1-silenced cells. Here we report that autophagosome formation is promoted in the early phase in response to PINK1 gene silencing by lentivirus transfer vectors expressed in mouse striatum. Reduced PP2A activity and increased phosphorylation of PP2A at Y307 (inactive form of PP2A) were observed in PINK1-knockdown dopaminergic cells and striatum tissues. Treatment with C2-ceramide (an agonist of PP2A) reduced autophagy levels in PINK1-silenced MN9D cells, which suggests that PP2A plays an important role in the PINK1-knockdown-induced autophagic pathway. Furthermore, phosphorylation of Bcl-2 at S87 increased in PINK1-silenced cells and was negatively regulated by additional treatment with C2-ceramide, which indicates that Bcl-2 may be downstream of PP2A inactivation in response to PINK1 dysfunction. Immunoprecipitation also revealed dissociation of the Bcl-2/Beclin1 complex in PINK1-silenced cells, which was reversed by additional treatment with C2-ceramide, and correlated with changes in level of autophagy and S87 phosphorylation of Bcl-2. Finally, Western blots for cleaved caspase-9 and flow cytometry results for active caspase-3 revealed that PP2A inactivation is involved in the protective effect of autophagy on PINK1-silenced cells. Our findings show that downregulation of PP2A activity in PINK1-silenced cells promotes the protective effect of autophagy through phosphorylation of Bcl-2 at S87 and blockage of the caspase pathway. These results may have implications for identifying the mechanism of PD.
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Affiliation(s)
- Zhifeng Qi
- Beijing Institute for Neuroscience, Capital Medical University, Beijing Center of Neural Regeneration and Repair, Key Laboratory for Neurodegenerative Disease of the Ministry of Education, Beijing 100069, China
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33
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Voronkov M, Braithwaite SP, Stock JB. Phosphoprotein phosphatase 2A: a novel druggable target for Alzheimer's disease. Future Med Chem 2011; 3:821-33. [PMID: 21644827 PMCID: PMC3292348 DOI: 10.4155/fmc.11.47] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Tau hyperphosphorylation is thought to play an important role in the etiology of Alzheimer's disease by facilitating the formation of neurofibrillary tangles. Reducing phosphorylation through kinase inhibition has therefore emerged as a target for drug development, but despite considerable efforts to develop therapeutic kinase inhibitors, success has been limited. An alternative approach is to develop pharmaceuticals to enhance the activity of the principal phospho-tau phosphatase, phosphoprotein phosphatase 2A (PP2A). In this article we review evidence that this mechanism is pharmacologically achievable and has promise for delivering the next generation of Alzheimer's disease therapeutics. A number of different chemotypes have been reported to lead to enhanced PP2A activity through a range of proposed mechanisms. Some of these compounds appear to act directly as allosteric activators of PP2A, while others act indirectly by inhibiting the binding of PP2A inhibitors or by altering post-translational modifications that act in turn to regulate PP2A activity towards phospho-tau. These results indicate that PP2A may provide a useful target that can be safely, selectively and effectively modulated through pharmaceutical intervention to treat Alzheimer's disease.
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Affiliation(s)
| | | | - Jeffry B Stock
- Signum Biosciences, Monmouth Junction, NJ 08852, USA
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
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Switzer CH, Cheng RYS, Vitek TM, Christensen DJ, Wink DA, Vitek MP. Targeting SET/I(2)PP2A oncoprotein functions as a multi-pathway strategy for cancer therapy. Oncogene 2011; 30:2504-13. [PMID: 21297667 PMCID: PMC3107340 DOI: 10.1038/onc.2010.622] [Citation(s) in RCA: 138] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The SET oncoprotein participates in cancer progression by affecting multiple cellular processes, inhibiting the tumor suppressor protein phosphatase 2A (PP2A), and inhibiting the metastasis suppressor nm23-H1. On the basis of these multiple activities, we hypothesized that targeted inhibition of SET would have multiple discrete and measurable effects on cancer cells. Here, the effects of inhibiting SET oncoprotein function on intracellular signaling and proliferation of human cancer cell lines was investigated. We observed the effects of COG112, a novel SET interacting peptide, on PP2A activity, Akt signaling, nm23-H1 activity and cellular migration/invasion in human U87 glioblastoma and MDA-MB-231 breast adenocarcinoma cancer cell lines. We found that COG112 interacted with SET protein and inhibited the association between SET and PP2A catalytic subunit (PP2A-c) and nm23-H1. The interaction between COG112 and SET caused PP2A phosphatase and nm23-H1 exonuclease activities to increase. COG112-mediated increases in PP2A activity resulted in the inhibition of Akt signaling and cellular proliferation. Additionally, COG112 inhibited SET association with Ras-related C(3) botulinum toxin substrate 1 (Rac1), leading to decreased cellular migration and invasion. COG112 treatment releases the SET-mediated inhibition of the tumor suppressor PP2A, as well as the metastasis suppressor nm23-H1. These results establish SET as a novel molecular target and that the inhibition of SET may have beneficial effects in cancer chemotherapy.
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Affiliation(s)
- C H Switzer
- Radiation Biology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
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35
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Hamano R, Miyata H, Yamasaki M, Kurokawa Y, Hara J, Moon JH, Nakajima K, Takiguchi S, Fujiwara Y, Mori M, Doki Y. Overexpression of miR-200c induces chemoresistance in esophageal cancers mediated through activation of the Akt signaling pathway. Clin Cancer Res 2011; 17:3029-38. [PMID: 21248297 DOI: 10.1158/1078-0432.ccr-10-2532] [Citation(s) in RCA: 197] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
PURPOSE To determine the relationship between resistance to chemotherapy and microRNA (miRNA) expression in esophageal cancer, we focused on miRNAs known to be associated with maintenance of stem cell function. EXPERIMENTAL DESIGN Using 98 formalin-fixed, paraffin-embedded samples obtained from patients with esophageal cancer who had received preoperative chemotherapy followed by surgery, we measured expression levels of several miRNAs that are considered to be involved in the regulation of stem cell function (e.g., let-7a, let-7g, miR-21, miR-134, miR-145, miR-155, miR-200c, miR-203, and miR-296) by real-time reverse transcriptase PCR. Then, we examined the relationship between miRNA expression and prognosis or response to chemotherapy. To investigate the mechanism of miRNA-induced chemoresistance, in vitro assays were carried out using esophageal cancer cells. RESULTS Analyses of the 9 miRNAs expression showed that overexpression of miR-200c (P = 0.037), underexpression of miR-145 (P = 0.023), and overexpression of miR-21 (P = 0.048) correlated significantly with shortened overall duration of survival. In particular, miR-200c expression correlated significantly with response to chemotherapy (P = 0.009 for clinical response; P = 0.007 for pathologic response). In vitro assay showed significantly increased miR-200c expression in cisplatin-resistant cells compared with their parent cells (∼1.7-fold). In anti-miR-200c-transfected cells, chemosensitivity to cisplatin and apoptosis after exposure to cisplatin was found to increase as compared with the negative control. Western blotting showed that knockdown of miR-200c expression was associated with increased expression of PPP2R1B, a subunit of protein phosphatase 2A, which resulted in reduced expression of phospho-Akt. CONCLUSIONS Results of this study emphasized the involvement of miR-200c in resistance to chemotherapy among esophageal cancers and that this effect was mediated through the Akt pathway.
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Affiliation(s)
- Rie Hamano
- Department of Gastroenterological Surgery, Osaka University Graduate School of Medicine, Osaka, Japan
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