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Hoock JGF, Rossetti C, Bilgin M, Depta L, Enemark-Rasmussen K, Christianson JC, Laraia L. Identification of non-conventional small molecule degraders and stabilizers of squalene synthase. Chem Sci 2023; 14:12973-12983. [PMID: 38023519 PMCID: PMC10664564 DOI: 10.1039/d3sc04064j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 10/15/2023] [Indexed: 12/01/2023] Open
Abstract
Squalene synthase (SQS) is an essential enzyme in the mevalonate pathway, which controls cholesterol biosynthesis and homeostasis. Although catalytic inhibitors of SQS have been developed, none have been approved for therapeutic use so far. Herein we sought to develop SQS degraders using targeted protein degradation (TPD) to lower overall cellular cholesterol content. We found that KY02111, a small molecule ligand of SQS, selectively causes SQS to degrade in a proteasome-dependent manner. Unexpectedly, compounds based on the same scaffold linked to E3 ligase recruiting ligands led to SQS stabilization. Proteomic analysis found KY02111 to reduce only the levels of SQS, while lipidomic analysis determined that KY02111-induced degradation lowered cellular cholesteryl ester content. Stabilizers shielded SQS from its natural turnover without recruiting their matching E3 ligase or affecting enzymatic target activity. Our work shows that degradation of SQS is possible despite a challenging biological setting and provides the first chemical tools to degrade and stabilize SQS.
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Affiliation(s)
- Joseph G F Hoock
- Department of Chemistry, Technical University of Denmark Kemitorvet 207 Kongens Lyngby 2800 Denmark
| | - Cecilia Rossetti
- Department of Chemistry, Technical University of Denmark Kemitorvet 207 Kongens Lyngby 2800 Denmark
| | - Mesut Bilgin
- Lipidomics Core Facility, Danish Cancer Institute Strandboulevarden 49 Copenhagen 2100 Denmark
| | - Laura Depta
- Department of Chemistry, Technical University of Denmark Kemitorvet 207 Kongens Lyngby 2800 Denmark
| | - Kasper Enemark-Rasmussen
- Department of Chemistry, Technical University of Denmark Kemitorvet 207 Kongens Lyngby 2800 Denmark
| | - John C Christianson
- Nuffield Department of Rheumatology, Orthopaedics, and Musculoskeletal Sciences, Botnar Research Centre, University of Oxford Headington Oxford OX3 7LD UK
| | - Luca Laraia
- Department of Chemistry, Technical University of Denmark Kemitorvet 207 Kongens Lyngby 2800 Denmark
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2
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Chen YC, Chen CY, Chiang TW, Chan MH, Hsiao M, Ke HM, Tsai I, Chuang TJ. Detecting intragenic trans-splicing events from non-co-linearly spliced junctions by hybrid sequencing. Nucleic Acids Res 2023; 51:7777-7797. [PMID: 37497782 PMCID: PMC10450196 DOI: 10.1093/nar/gkad623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 07/14/2023] [Indexed: 07/28/2023] Open
Abstract
Trans-spliced RNAs (ts-RNAs) are a type of non-co-linear (NCL) transcripts that consist of exons in an order topologically inconsistent with the corresponding DNA template. Detecting ts-RNAs is often interfered by experimental artifacts, circular RNAs (circRNAs) and genetic rearrangements. Particularly, intragenic ts-RNAs, which are derived from separate precursor mRNA molecules of the same gene, are often mistaken for circRNAs through analyses of RNA-seq data. Here we developed a bioinformatics pipeline (NCLscan-hybrid), which integrated short and long RNA-seq reads to minimize false positives and proposed out-of-circle and rolling-circle long reads to distinguish between intragenic ts-RNAs and circRNAs. Combining NCLscan-hybrid screening and multiple experimental validation steps successfully confirmed that four NCL events, which were previously regarded as circRNAs in databases, originated from trans-splicing. CRISPR-based endogenous genome modification experiments further showed that flanking intronic complementary sequences can significantly contribute to ts-RNA formation, providing an efficient/specific method to deplete ts-RNAs. We also experimentally validated that one ts-RNA (ts-ARFGEF1) played an important role for p53-mediated apoptosis through affecting the PERK/eIF2a/ATF4/CHOP signaling pathway in breast cancer cells. This study thus described both bioinformatics procedures and experimental validation steps for rigorous characterization of ts-RNAs, expanding future studies for identification, biogenesis, and function of these important but understudied transcripts.
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Affiliation(s)
- Yu-Chen Chen
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
| | - Chia-Ying Chen
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
| | - Tai-Wei Chiang
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
| | - Ming-Hsien Chan
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
- Department of Biomedical Imaging and Radiological Sciences, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Michael Hsiao
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
| | - Huei-Mien Ke
- Biodiversity Research Center, Academia Sinica, Taipei, Taiwan
- Department of Microbiology, Soochow University, Taipei, Taiwan
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Bean ML, Alkohaif RA, Anbari A, Fedraw CP, Ghantasala V, Gojcaj F, Hanein P, Harris MR, Kim D, Proffett DLD, Husseini MH, James EA, O'Rourke BM, Sareini LH, Livezey MR. Computational approaches to identify a novel binding site of BHPI on estrogen receptor alpha. Steroids 2022; 186:109075. [PMID: 35792153 DOI: 10.1016/j.steroids.2022.109075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Revised: 06/15/2022] [Accepted: 06/29/2022] [Indexed: 11/26/2022]
Abstract
3,3-bis(4-hydroxyphenyl)-7-methyl-1,3,dihydro-2H-indol-2-one (BHPI) is a biomodulator of Estrogen Receptor alpha (ERα) that targets ERα positive cancer cells by activating the unfolded protein response (UPR). BHPI induces strong and sustained activation of this pathway, eventually resulting in necrotic cell death. While much is known about how BHPI triggers the UPR leading to necrotic cell death, it is not known how BHPI binds to its putative molecular target, ERα. In an effort to identify the binding site of BHPI on ERα, molecular docking studies in AutoDock Vina were utilized. Unexpectedly, BHPI was found to dock more frequently and with significantly better binding affinity to a newly described surface pocket on the ERα ligand-binding domain, compared to the ligand-binding pocket. This work uncovers a novel binding site for small molecules on ERα that is not targeted by classical ligands, such as estrogen and tamoxifen, and may allow for the design of additional anti-cancer drugs that work in distinct ways.
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Affiliation(s)
- Monica L Bean
- University of Detroit Mercy. 4001 W. McNichols Rd, Detroit, MI 48221, US; Meharry Medical College. 1005 Dr DB Todd Jr Blvd, Nashville, TN 37208, US
| | - Reham A Alkohaif
- University of Detroit Mercy. 4001 W. McNichols Rd, Detroit, MI 48221, US
| | - Ahed Anbari
- University of Detroit Mercy. 4001 W. McNichols Rd, Detroit, MI 48221, US
| | - Caela P Fedraw
- University of Detroit Mercy. 4001 W. McNichols Rd, Detroit, MI 48221, US
| | - Vishnu Ghantasala
- University of Detroit Mercy. 4001 W. McNichols Rd, Detroit, MI 48221, US
| | - Florina Gojcaj
- University of Detroit Mercy. 4001 W. McNichols Rd, Detroit, MI 48221, US
| | - Philopateer Hanein
- University of Detroit Mercy. 4001 W. McNichols Rd, Detroit, MI 48221, US
| | - Myles R Harris
- University of Detroit Mercy. 4001 W. McNichols Rd, Detroit, MI 48221, US
| | - Dennis Kim
- University of Detroit Mercy. 4001 W. McNichols Rd, Detroit, MI 48221, US
| | | | - Mahdi H Husseini
- University of Detroit Mercy. 4001 W. McNichols Rd, Detroit, MI 48221, US
| | - Elizabeth A James
- University of Detroit Mercy. 4001 W. McNichols Rd, Detroit, MI 48221, US; Xavier University of Louisiana. 1 Drexel Dr, New Orleans, LA 70125, US
| | - Brendan M O'Rourke
- University of Detroit Mercy. 4001 W. McNichols Rd, Detroit, MI 48221, US
| | - Laila H Sareini
- University of Detroit Mercy. 4001 W. McNichols Rd, Detroit, MI 48221, US
| | - Mara R Livezey
- University of Detroit Mercy. 4001 W. McNichols Rd, Detroit, MI 48221, US.
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Xu T, Jiang Y, Yuan S, Zhang L, Chen X, Zhao W, Cai L, Xiao B, Jia L. Andrographolide Inhibits ER-Positive Breast Cancer Growth and Enhances Fulvestrant Efficacy via ROS-FOXM1-ER-α Axis. Front Oncol 2022; 12:899402. [PMID: 35615146 PMCID: PMC9124841 DOI: 10.3389/fonc.2022.899402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 04/13/2022] [Indexed: 12/02/2022] Open
Abstract
Estrogen receptor (ER)-positive breast cancer is the main subtype of breast cancer (BRCA) with high incidence and mortality. Andrographolide (AD), a major active component derived from the traditional Chinese medicine Andrographis paniculate, has substantial anti-cancer effect in various tumors. However, the antitumor efficacy and the underlying molecular mechanisms of AD on ER-positive breast cancer are poorly understood. In the present study, we demonstrated that andrographolide (AD) significantly inhibited the growth of ER-positive breast cancer cells. Mechanistically, AD suppressed estrogen receptor 1 (ESR1, encodes ER-α) transcription to inhibit tumor growth. Further studies revealed that AD induced ROS production to down-regulate FOXM1-ER-α axis. Conversely, inhibiting ROS production with N-acetylcysteine (NAC) elevated AD-decreased ER-α expression, which could be alleviated by FOXM1 knockdown. In addition, AD in combination with fulvestrant (FUL) synergistically down-regulated ER-α expression to inhibit ER-positive breast cancer both in vitro and in vivo. These findings collectively indicate that AD suppresses ESR1 transcription through ROS-FOXM1 axis to inhibit ER-positive breast cancer growth and suggest that AD might be a potential therapeutic agent and fulvestrant sensitizer for ER-positive breast cancer treatment.
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Fan P, Jordan VC. Estrogen Receptor and the Unfolded Protein Response: Double-Edged Swords in Therapy for Estrogen Receptor-Positive Breast Cancer. Target Oncol 2022; 17:111-124. [PMID: 35290592 PMCID: PMC9007905 DOI: 10.1007/s11523-022-00870-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/23/2022] [Indexed: 01/07/2023]
Abstract
Estrogen receptor α (ERα) is a target for the treatment of ER-positive breast cancer patients. Paradoxically, it is also the initial site for estrogen (E2) to induce apoptosis in endocrine-resistant breast cancer. How ERα exhibits distinct functions, in different contexts, is the focus of numerous investigations. Compelling evidence demonstrated that unfolded protein response (UPR) is closely correlated with ER-positive breast cancer. Treatment with antiestrogens initially induces mild UPR through ERα with activation of three sensors of UPR-PRK-like endoplasmic reticulum kinase (PERK), inositol-requiring enzyme 1α (IRE1α), and activating transcription factor 6 (ATF6)-in the endoplasmic reticulum. Subsequently, these sensors interact with stress-associated transcription factors such as c-MYC, nuclear factor-κB (NF-κB), and hypoxia-inducible factor 1α (HIF1α), leading to acquired endocrine resistance. Paradoxically, E2 further activates sustained secondary UPR via ERα to induce apoptosis in endocrine-resistant breast cancer. Specifically, PERK plays a key role in inducing apoptosis, whereas IRE1α and ATF6 are involved in endoplasmic reticulum stress-associated degradation after E2 treatment. Furthermore, persistent activation of PERK deteriorates stress responses in mitochondria and triggers of NF-κB/tumor necrosis factor α (TNFα) axis, ultimately determining cell fate to apoptosis. The discovery of E2-induced apoptosis has clinical relevance for treatment of endocrine-resistant breast cancer. All of these findings demonstrate that ERα and associated UPR are double-edged swords in therapy for ER-positive breast cancer, depending on the duration and intensity of UPR stress. Herein, we address the mechanistic progress on how UPR leads to endocrine resistance and commits E2 to inducing apoptosis in endocrine-resistant breast cancer.
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Affiliation(s)
- Ping Fan
- Department of Breast Medical Oncology, Unit 1354, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd, Houston, Texas, TX 77030, USA
| | - V Craig Jordan
- Department of Breast Medical Oncology, Unit 1354, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd, Houston, Texas, TX 77030, USA.
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6
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Schwartz G, Shee K, Romo B, Marotti J, Kisselev A, Lewis L, Miller T. Phase Ib Study of the Oral Proteasome Inhibitor Ixazomib (MLN9708) and Fulvestrant in Advanced ER+ Breast Cancer Progressing on Fulvestrant. Oncologist 2021; 26:467-e924. [PMID: 33641211 PMCID: PMC8176977 DOI: 10.1002/onco.13733] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 02/10/2021] [Indexed: 12/28/2022] Open
Abstract
LESSONS LEARNED Fulvestrant is a selective estrogen receptor (ER)-downregulating antiestrogen that blocks ER transcriptional activity and is approved for ER-positive breast cancer. Fulvestrant also induces accumulation of insoluble ER and activates an unfolded protein response; proteasome inhibitors have been shown to enhance these effects in preclinical models. BACKGROUND Fulvestrant is a selective estrogen receptor (ER)-downregulating antiestrogen that blocks ER transcriptional activity and is approved for ER-positive (+) breast cancer. Fulvestrant also induces accumulation of insoluble ER and activates an unfolded protein response; proteasome inhibitors have been shown to enhance these effects in preclinical models. METHODS This is a single-center phase Ib study with a 3+3 design of fulvestrant and the proteasome inhibitor ixazomib (MLN9708) in patients with advanced ER+ breast cancer that was progressing on fulvestrant. A dose-escalation design allowed establishment of the ixazomib maximum tolerated dose (MTD). Secondary objectives included progression-free survival, pharmacokinetics, and tumor molecular analyses. RESULTS Among nine evaluable subjects, treatment was well-tolerated without dose-limiting toxicities The MTD of ixazomib was 4 mg in combination with fulvestrant. Plasma concentrations of the active form of ixazomib (MLN2238) in the 4-mg dose cohort had a median (range) maximal concentration (Cmax ) of 155 (122-171) ng/mL, time of maximal concentration (Tmax ) of 1 (1-1.5) hour, terminal elimination half-life of 66.6 (57.3-102.6) hour after initial dose, and area under the curve (AUC) of 5,025 (4,160-5,345) ng*h/mL. One partial response was observed, and median progression-free survival was 51 days (range, 47-137). CONCLUSION This drug combination has a favorable safety profile and antitumor activity in patients with fulvestrant-resistant advanced ER+ breast cancer that justifies future testing.
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Affiliation(s)
- Gary Schwartz
- Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire, USA
| | - Kevin Shee
- Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire, USA
| | - Bianca Romo
- Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire, USA
| | - Jonathan Marotti
- Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire, USA
| | | | - Lionel Lewis
- Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire, USA
| | - Todd Miller
- Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire, USA
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7
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Molehin D, Rasha F, Rahman RL, Pruitt K. Regulation of aromatase in cancer. Mol Cell Biochem 2021; 476:2449-2464. [PMID: 33599895 DOI: 10.1007/s11010-021-04099-0] [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] [Received: 09/25/2020] [Accepted: 02/04/2021] [Indexed: 12/21/2022]
Abstract
The regulation of aromatase, an enzyme involved in the biosynthesis of estrogen in normal and cancer cells, has been associated with growth factor signaling and immune response modulation. The tissue-specific regulatory roles of these factors are of particular importance as local aromatase expression is strongly linked to cancer development/progression and disease outcomes in patients. Therefore, aromatase has become a chemotherapeutic target and aromatase inhibitors (AIs) are used in the clinic for treating hormone-dependent cancers. Although AIs have shown promising results in the treatment of cancers, the emerging increase in AI-resistance necessitates the development of new and improved targeted therapies. This review discusses the role of tumor and stromal-derived growth factors and immune cell modulators in regulating aromatase. Current single-agent and combination therapies with or without AIs targeting growth factors and immune checkpoints are also discussed. This review highlights recent studies that show new connections between growth factors, mediators of immune response, and aromatase regulation.
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Affiliation(s)
- Deborah Molehin
- Department of Immunology & Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Fahmida Rasha
- Department of Immunology & Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | | | - Kevin Pruitt
- Department of Immunology & Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX, USA. .,Department of Immunology & Molecular Microbiology, Texas Tech University Health Sciences Center, 3601 4th Street, Lubbock, TX, 79430-6591, USA.
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Jeffreys SA, Powter B, Balakrishnar B, Mok K, Soon P, Franken A, Neubauer H, de Souza P, Becker TM. Endocrine Resistance in Breast Cancer: The Role of Estrogen Receptor Stability. Cells 2020; 9:cells9092077. [PMID: 32932819 PMCID: PMC7564140 DOI: 10.3390/cells9092077] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 09/06/2020] [Accepted: 09/08/2020] [Indexed: 12/13/2022] Open
Abstract
Therapy of hormone receptor positive breast cancer (BCa) generally targets estrogen receptor (ER) function and signaling by reducing estrogen production or by blocking its interaction with the ER. Despite good long-term responses, resistance to treatment remains a significant issue, with approximately 40% of BCa patients developing resistance to ET. Mutations in the gene encoding ERα, ESR1, have been identified in BCa patients and are implicated as drivers of resistance and disease recurrence. Understanding the molecular consequences of these mutations on ER protein levels and its activity, which is tightly regulated, is vital. ER activity is in part controlled via its short protein half-life and therefore changes to its stability, either through mutations or alterations in pathways involved in protein stability, may play a role in therapy resistance. Understanding these connections and how ESR1 alterations could affect protein stability may identify novel biomarkers of resistance. This review explores the current reported data regarding posttranslational modifications (PTMs) of the ER and the potential impact of known resistance associated ESR1 mutations on ER regulation by affecting these PTMs in the context of ET resistance.
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Affiliation(s)
- Sarah A. Jeffreys
- Centre for Circulating Tumour Cells Diagnostics & Research, Ingham Institute of Applied Medical Research, Liverpool NSW 2170, Australia; (B.P.); (P.S.); (A.F.); (P.d.S.); (T.M.B.)
- School of Medicine, Western Sydney University, Campbelltown NSW 2560, Australia
- Correspondence: ; Tel.: +61-2-873-89022
| | - Branka Powter
- Centre for Circulating Tumour Cells Diagnostics & Research, Ingham Institute of Applied Medical Research, Liverpool NSW 2170, Australia; (B.P.); (P.S.); (A.F.); (P.d.S.); (T.M.B.)
| | - Bavanthi Balakrishnar
- Department of Medical Oncology, Liverpool Hospital, Liverpool NSW 2170, Australia; (B.B.); (K.M.)
| | - Kelly Mok
- Department of Medical Oncology, Liverpool Hospital, Liverpool NSW 2170, Australia; (B.B.); (K.M.)
| | - Patsy Soon
- Centre for Circulating Tumour Cells Diagnostics & Research, Ingham Institute of Applied Medical Research, Liverpool NSW 2170, Australia; (B.P.); (P.S.); (A.F.); (P.d.S.); (T.M.B.)
- South Western Sydney Clinical School, University of New South Wales, Liverpool Hospital, Liverpool NSW 2170, Australia
- Department of Surgery, Bankstown Hospital, Bankstown NSW 2200, Australia
| | - André Franken
- Centre for Circulating Tumour Cells Diagnostics & Research, Ingham Institute of Applied Medical Research, Liverpool NSW 2170, Australia; (B.P.); (P.S.); (A.F.); (P.d.S.); (T.M.B.)
- Department of Obstetrics and Gynaecology, University Hospital and Medical Faculty of the Heinrich-Heine University Düsseldorf, 40225 Düsseldorf, Germany;
| | - Hans Neubauer
- Department of Obstetrics and Gynaecology, University Hospital and Medical Faculty of the Heinrich-Heine University Düsseldorf, 40225 Düsseldorf, Germany;
| | - Paul de Souza
- Centre for Circulating Tumour Cells Diagnostics & Research, Ingham Institute of Applied Medical Research, Liverpool NSW 2170, Australia; (B.P.); (P.S.); (A.F.); (P.d.S.); (T.M.B.)
- School of Medicine, Western Sydney University, Campbelltown NSW 2560, Australia
- Department of Medical Oncology, Liverpool Hospital, Liverpool NSW 2170, Australia; (B.B.); (K.M.)
- South Western Sydney Clinical School, University of New South Wales, Liverpool Hospital, Liverpool NSW 2170, Australia
- School of Medicine, University of Wollongong, Wollongong NSW 2522, Australia
| | - Therese M. Becker
- Centre for Circulating Tumour Cells Diagnostics & Research, Ingham Institute of Applied Medical Research, Liverpool NSW 2170, Australia; (B.P.); (P.S.); (A.F.); (P.d.S.); (T.M.B.)
- School of Medicine, Western Sydney University, Campbelltown NSW 2560, Australia
- South Western Sydney Clinical School, University of New South Wales, Liverpool Hospital, Liverpool NSW 2170, Australia
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9
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Direito I, Fardilha M, Helguero LA. Contribution of the unfolded protein response to breast and prostate tissue homeostasis and its significance to cancer endocrine response. Carcinogenesis 2019; 40:203-215. [PMID: 30596981 DOI: 10.1093/carcin/bgy182] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2018] [Revised: 12/05/2018] [Accepted: 12/14/2018] [Indexed: 12/25/2022] Open
Abstract
Resistant breast and prostate cancers remain a major clinical problem, new therapeutic approaches and better predictors of therapeutic response are clearly needed. Because of the involvement of the unfolded protein response (UPR) in cell proliferation and apoptosis evasion, an increasing number of publications support the hypothesis that impairments in this network trigger and/or exacerbate cancer. Moreover, UPR activation could contribute to the development of drug resistance phenotypes in both breast and prostate cancers. Therefore, targeting this pathway has recently emerged as a promising strategy in anticancer therapy. This review addresses the contribution of UPR to breast and prostate tissues homeostasis and its significance to cancer endocrine response with focus on the current progress on UPR research related to cancer biology, detection, prognosis and treatment.
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Affiliation(s)
| | - Margarida Fardilha
- Signal Transduction Laboratory, Department of Medical Sciences, Institute for Biomedicine (iBiMED), Universidade de Aveiro, Aveiro, Portugal
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10
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Liu Y, Wang X, Zhu T, Zhang N, Wang L, Huang T, Cao Y, Li W, Zhang J. Resistance to bortezomib in breast cancer cells that downregulate Bim through FOXA1 O‐GlcNAcylation. J Cell Physiol 2019; 234:17527-17537. [DOI: 10.1002/jcp.28376] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 01/16/2019] [Indexed: 12/29/2022]
Affiliation(s)
- Yubo Liu
- Department of Biochemistry, School of Life Science & Medicine, Dalian University of Technology Panjin China
| | - Xue Wang
- Department of Biochemistry, School of Life Science & Medicine, Dalian University of Technology Panjin China
| | - Tong Zhu
- Department of Biochemistry, School of Life Science & Medicine, Dalian University of Technology Panjin China
| | - Nana Zhang
- Department of Biochemistry, School of Life Science & Medicine, Dalian University of Technology Panjin China
| | - Lingyan Wang
- Department of Biochemistry, School of Life Science & Medicine, Dalian University of Technology Panjin China
| | - Tianmiao Huang
- Department of Biochemistry, School of Life Science & Medicine, Dalian University of Technology Panjin China
| | - Yu Cao
- Department of Biochemistry, School of Life Science & Medicine, Dalian University of Technology Panjin China
| | - Wenli Li
- Department of Biochemistry, School of Life Science & Medicine, Dalian University of Technology Panjin China
- Department of Biochemistry, School of Life Science & Biotechnology, Dalian University of Technology Dalian China
| | - Jianing Zhang
- Department of Biochemistry, School of Life Science & Medicine, Dalian University of Technology Panjin China
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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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12
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Thaler S, Schmidt M, Roβwag S, Thiede G, Schad A, Sleeman JP. Proteasome inhibitors prevent bi-directional HER2/estrogen-receptor cross-talk leading to cell death in endocrine and lapatinib-resistant HER2+/ER+ breast cancer cells. Oncotarget 2017; 8:72281-72301. [PMID: 29069787 PMCID: PMC5641130 DOI: 10.18632/oncotarget.20261] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 08/04/2017] [Indexed: 12/26/2022] Open
Abstract
Amplification and/or overexpression of the human epidermal growth factor 2 (HER2) oncogene occurs in about 13–15% of invasive breast cancer and triggers breast cancer cell proliferation, survival and metastatic progression. Around half of all breast cancers with HER2 overexpression co-express hormone receptors (HR) such as those for estrogen and progesterone. Aberrant signaling through HER2 and other members of the HER-family mediates endocrine-resistance in estrogen receptor alpha (ERα) positive breast cancer. On the other hand, ERα co-expression has been shown to attenuate the efficiency of anti-HER2 therapies. These findings indicate that HER2 and ERα synergize to escape from both anti-ERα and anti-HER2-targeted therapies. Rationally designed clinical trials that combine endocrine therapy with anti-HER2 agents to interfere with HER2/ERα cross-talk have been conducted. However, the outcome of these trials suggests that novel therapeutic approaches are needed to further improve inhibition of HER2 and other HER-family members in conjunction with a more efficient ERα blockade. Here, we demonstrate that carfilzomib and bortezomib stabilize the HER2-specific protein tyrosine phosphatase BDP1 leading to decreased HER2 autophosphorylation, reduced HER2 activity and subsequently attenuated activation of the PI3K/Akt-pathway, together with blockade of ERα expression. We further observed that proteasome inhibitors (PIs) reverse autophosphorylation and thereby inhibit the activity of constitutively active mutant HER2. We also demonstrate that PIs cause cell death in lapatinib and endocrine-resistant HER2+/ER+ breast cancer cells. These findings suggest that PIs might have the potential to improve the management of HER2+/ER+ breast cancer patients by efficiently disrupting the bi-directional HER2/ERα cross-talk.
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Affiliation(s)
- Sonja Thaler
- Centre for Biomedicine and Medical Technology Mannheim (CBTM), Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Marcus Schmidt
- Department of Obstetrics and Gynecology, University Medical Center, Johannes Gutenberg University, Mainz, Germany
| | - Sven Roβwag
- Centre for Biomedicine and Medical Technology Mannheim (CBTM), Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Gitta Thiede
- Centre for Biomedicine and Medical Technology Mannheim (CBTM), Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Arno Schad
- Institute of Pathology, University Medical Center, Johannes Gutenberg University, Mainz, Germany
| | - Jonathan P Sleeman
- Centre for Biomedicine and Medical Technology Mannheim (CBTM), Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany.,KIT Campus Nord, Institute for Toxicology and Genetics, Karlsruhe, Germany
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Adelson K, Ramaswamy B, Sparano JA, Christos PJ, Wright JJ, Raptis G, Han G, Villalona-Calero M, Ma CX, Hershman D, Baar J, Klein P, Cigler T, Budd GT, Novik Y, Tan AR, Tannenbaum S, Goel A, Levine E, Shapiro CL, Andreopoulou E, Naughton M, Kalinsky K, Waxman S, Germain D. Randomized phase II trial of fulvestrant alone or in combination with bortezomib in hormone receptor-positive metastatic breast cancer resistant to aromatase inhibitors: a New York Cancer Consortium trial. NPJ Breast Cancer 2016; 2:16037. [PMID: 28721390 PMCID: PMC5515340 DOI: 10.1038/npjbcancer.2016.37] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 09/09/2016] [Accepted: 10/18/2016] [Indexed: 11/09/2022] Open
Abstract
The proteasome inhibitor bortezomib enhances the effect of the selective estrogen receptor (ER) downregulator (SERD) fulvestrant by causing accumulation of cytoplasmic ER aggregates in preclinical models. The purpose of this trial was to determine whether bortezomib enhanced the effectiveness of fulvestrant. One hundred eighteen postmenopausal women with ER-positive metastatic breast cancer resistant to aromatase inhibitors (AIs) were randomized to fulvestrant alone (Arm A-500 mg intramuscular (i.m.) day -14, 1, 15 in cycle 1, and day 1 of additional cycles) or in combination with bortezomib (Arm B-1.6 mg/m2 intravenous (i.v.) on days 1, 8, 15 of each cycle). The study was powered to show an improvement in median progression-free survival (PFS) from 5.4 to 9.0 months and compare PFS rates at 6 and 12 months (α=0.10, β=0.10). Patients with progression on fulvestrant could cross over to the combination (arm C). Although there was no difference in median PFS (2.7 months in both arms), the hazard ratio for PFS in Arm B versus Arm A (referent) was 0.73 (95% confidence interval (CI)=0.49, 1.09, P=0.06, 1-sided log-rank test, significant at the prespecified 1-sided 0.10 α level). At 12 months, the PFS proportion in Arm A and Arm B was 13.6% and 28.1% (P=0.03, 1-sided χ2-test; 95% CI for difference (14.5%)=-0.06, 29.1%). Of 27 patients on arm A who crossed over to the combination (arm C), 5 (18%) were progression-free for at least 24 weeks. Bortezomib likely enhances the effectiveness of fulvestrant in AI-resistant, ER-positive metastatic breast cancer by reducing acquired resistance, supporting additional evaluation of proteasome inhibitors in combination with SERDs.
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Affiliation(s)
- Kerin Adelson
- Yale Cancer Center and Smilow Cancer Hospital, Yale University School of Medicine, New Haven, CT, USA
| | | | - Joseph A Sparano
- Department of Oncology, Montefiore Medical Center, Bronx, NY, USA
| | - Paul J Christos
- Department of Healthcare Policy & Research, Weill Cornell Medical Center, New York, NY, USA
| | - John J Wright
- Investigational Drug Branch, Cancer Therapy and Evaluation Program, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - George Raptis
- Department of Medicine, Northwell Health, Lake Success NY and Hofstra Northwell School of Medicine, Hempstead, NY, USA
| | - Gang Han
- Department of Epidemiology and Biostatistics, School of Public Health, Texas A&M University, College Station, TX, USA
| | | | - Cynthia X Ma
- Department of Internal Medicine, Washington University School of Medicine, St Louis, MO, USA
| | - Dawn Hershman
- Department of Medicine and Epidemiology New York Presbyterian-Columbia University Medical Center, New York, NY, NY, USA
| | - Joseph Baar
- Department of Medicine, Division of Hematology/Oncology, Seidman Cancer Center of the University Hospitals of the Cleveland Medical Center, Cleveland, OH, USA
| | - Paula Klein
- Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, Mount Sinai Health System, New York, NY, USA
| | - Tessa Cigler
- Division of Hematology and Oncology, Department of Medicine, Weill Cornell Medical Center, New York, NY, USA
| | - G Thomas Budd
- Department of Hematology and Medical Oncology, Cleveland Clinic Taussig Cancer Center, Cleveland, OH, USA
| | - Yelena Novik
- Perlmutter Cancer Center, NYU Langone Medical Center, New York University School of Medicine, New York, NY, USA
| | - Antoinette R Tan
- Department of Medical Oncology, Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, USA
| | - Susan Tannenbaum
- Department of Medicine, University of Connecticut Health Center, Farmington, CT, USA
| | - Anupama Goel
- Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, Mount Sinai Health System, New York, NY, USA
| | - Ellis Levine
- Roswell Park Cancer Institute, Jacobs School of Medicine and Biomedical Science, State University of New York at Buffalo, Buffalo, NY, USA
| | - Charles L Shapiro
- The Ohio State Comprehensive Cancer Center, Ohio State University, Columbus, OH, USA
| | | | - Michael Naughton
- Department of Internal Medicine, Washington University School of Medicine, St Louis, MO, USA
| | - Kevin Kalinsky
- Department of Medicine, Division of Hematology and Oncology, New York Presbyterian-Columbia University Medical Center, New York, NY, USA
| | - Sam Waxman
- Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, Mount Sinai Health System, New York, NY, USA
| | - Doris Germain
- Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, Mount Sinai Health System, New York, NY, USA
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14
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Shapiro DJ, Livezey M, Yu L, Zheng X, Andruska N. Anticipatory UPR Activation: A Protective Pathway and Target in Cancer. Trends Endocrinol Metab 2016; 27:731-741. [PMID: 27354311 PMCID: PMC5035594 DOI: 10.1016/j.tem.2016.06.002] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Revised: 06/02/2016] [Accepted: 06/06/2016] [Indexed: 01/18/2023]
Abstract
The endoplasmic reticulum (EnR) stress sensor, the unfolded protein response (UPR), plays a key role in regulating intracellular protein homeostasis. The extensively studied reactive mode of UPR activation is characterized by unfolded protein, or other EnR stress, triggering UPR activation. Here we focus on the emerging anticipatory mode of UPR activation in which mitogenic steroid and peptide hormones and other effectors preactivate the UPR and anticipate a future need for increased protein folding capacity. Mild UPR activation in breast cancer can be protective and contributes to antiestrogen resistance. Hyperactivation of the anticipatory UPR pathway in cancer cells with a small molecule converts it from cytoprotective to cytotoxic, highlighting its potential as a therapeutic target in estrogen receptor-positive breast cancer.
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Affiliation(s)
- David J Shapiro
- Department of Biochemistry, University of Illinois, Urbana, IL 61801, USA.
| | - Mara Livezey
- Department of Biochemistry, University of Illinois, Urbana, IL 61801, USA
| | - Liqun Yu
- Department of Biochemistry, University of Illinois, Urbana, IL 61801, USA
| | - Xiaobin Zheng
- Department of Biochemistry, University of Illinois, Urbana, IL 61801, USA
| | - Neal Andruska
- Department of Biochemistry, University of Illinois, Urbana, IL 61801, USA; College of Medicine, University of Illinois, Urbana, IL 61801, USA
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15
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Cook KL, Soto-Pantoja DR, Clarke PAG, Cruz MI, Zwart A, Wärri A, Hilakivi-Clarke L, Roberts DD, Clarke R. Endoplasmic Reticulum Stress Protein GRP78 Modulates Lipid Metabolism to Control Drug Sensitivity and Antitumor Immunity in Breast Cancer. Cancer Res 2016; 76:5657-5670. [PMID: 27698188 PMCID: PMC5117832 DOI: 10.1158/0008-5472.can-15-2616] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Accepted: 06/03/2016] [Indexed: 02/07/2023]
Abstract
The unfolded protein response is an endoplasmic reticulum stress pathway mediated by the protein chaperone glucose regulated-protein 78 (GRP78). Metabolic analysis of breast cancer cells shows that GRP78 silencing increases the intracellular concentrations of essential polyunsaturated fats, including linoleic acid. Accumulation of fatty acids is due to an inhibition of mitochondrial fatty acid transport, resulting in a reduction of fatty acid oxidation. These data suggest a novel role of GRP78-mediating cellular metabolism. We validated the effect of GRP78-regulated metabolite changes by treating tumor-bearing mice with tamoxifen and/or linoleic acid. Tumors treated with linoleic acid plus tamoxifen exhibited reduced tumor area and tumor weight. Inhibition of either GRP78 or linoleic acid treatment increased MCP-1 serum levels, decreased CD47 expression, and increased macrophage infiltration, suggesting a novel role for GRP78 in regulating innate immunity. GRP78 control of fatty acid oxidation may represent a new homeostatic function for GRP78. Cancer Res; 76(19); 5657-70. ©2016 AACR.
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Affiliation(s)
- Katherine L Cook
- Department of Surgery and Hypertension and Vascular Research Center, Wake Forest University School of Medicine, Winston-Salem, North Carolina. Department of Oncology and Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC.
| | - David R Soto-Pantoja
- Department of Surgery and Hypertension and Vascular Research Center, Wake Forest University School of Medicine, Winston-Salem, North Carolina
| | - Pamela A G Clarke
- Department of Oncology and Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC
| | - M Idalia Cruz
- Department of Oncology and Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC
| | - Alan Zwart
- Department of Oncology and Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC
| | - Anni Wärri
- Department of Oncology and Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC
| | - Leena Hilakivi-Clarke
- Department of Oncology and Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC
| | - David D Roberts
- Laboratory of Pathology, National Cancer Institute, NIH, Bethesda, Maryland
| | - Robert Clarke
- Department of Oncology and Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC
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16
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Kangaspeska S, Hultsch S, Jaiswal A, Edgren H, Mpindi JP, Eldfors S, Brück O, Aittokallio T, Kallioniemi O. Systematic drug screening reveals specific vulnerabilities and co-resistance patterns in endocrine-resistant breast cancer. BMC Cancer 2016; 16:378. [PMID: 27378269 PMCID: PMC4932681 DOI: 10.1186/s12885-016-2452-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Revised: 05/31/2016] [Accepted: 06/15/2016] [Indexed: 11/24/2022] Open
Abstract
Background The estrogen receptor (ER) inhibitor tamoxifen reduces breast cancer mortality by 31 % and has served as the standard treatment for ER-positive breast cancers for decades. However, 50 % of advanced ER-positive cancers display de novo resistance to tamoxifen, and acquired resistance evolves in 40 % of patients who initially respond. Mechanisms underlying resistance development remain poorly understood and new therapeutic opportunities are urgently needed. Here, we report the generation and characterization of seven tamoxifen-resistant breast cancer cell lines from four parental strains. Methods Using high throughput drug sensitivity and resistance testing (DSRT) with 279 approved and investigational oncology drugs, exome-sequencing and network analysis, we for the first time, systematically determine the drug response profiles specific to tamoxifen resistance. Results We discovered emerging vulnerabilities towards specific drugs, such as ERK1/2-, proteasome- and BCL-family inhibitors as the cells became tamoxifen-resistant. Co-resistance to other drugs such as the survivin inhibitor YM155 and the chemotherapeutic agent paclitaxel also occurred. Conclusion This study indicates that multiple molecular mechanisms dictate endocrine resistance, resulting in unexpected vulnerabilities to initially ineffective drugs, as well as in emerging co-resistances. Thus, combatting drug-resistant tumors will require patient-tailored strategies in order to identify new drug vulnerabilities, and to understand the associated co-resistance patterns. Electronic supplementary material The online version of this article (doi:10.1186/s12885-016-2452-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sara Kangaspeska
- Institute for Molecular Medicine Finland (FIMM), Biomedicum 2U, Tukholmankatu 8, 00290, Helsinki, Finland. .,Present address: Helsinki Innovation Services, Tukholmankatu 8 A, 00290, Helsinki, Finland.
| | - Susanne Hultsch
- Institute for Molecular Medicine Finland (FIMM), Biomedicum 2U, Tukholmankatu 8, 00290, Helsinki, Finland
| | - Alok Jaiswal
- Institute for Molecular Medicine Finland (FIMM), Biomedicum 2U, Tukholmankatu 8, 00290, Helsinki, Finland
| | - Henrik Edgren
- Institute for Molecular Medicine Finland (FIMM), Biomedicum 2U, Tukholmankatu 8, 00290, Helsinki, Finland.,Present address: MediSapiens Ltd, Erottajankatu 19B, 00130, Helsinki, Finland
| | - John-Patrick Mpindi
- Institute for Molecular Medicine Finland (FIMM), Biomedicum 2U, Tukholmankatu 8, 00290, Helsinki, Finland
| | - Samuli Eldfors
- Institute for Molecular Medicine Finland (FIMM), Biomedicum 2U, Tukholmankatu 8, 00290, Helsinki, Finland
| | - Oscar Brück
- Institute for Molecular Medicine Finland (FIMM), Biomedicum 2U, Tukholmankatu 8, 00290, Helsinki, Finland
| | - Tero Aittokallio
- Institute for Molecular Medicine Finland (FIMM), Biomedicum 2U, Tukholmankatu 8, 00290, Helsinki, Finland
| | - Olli Kallioniemi
- Institute for Molecular Medicine Finland (FIMM), Biomedicum 2U, Tukholmankatu 8, 00290, Helsinki, Finland.,Present address: Science for Life Laboratory, Department Oncology-Pathology, Karolinska Institutet, Tomtebodavägen 23, 171 65, Solna, Sweden
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17
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Vriend J, Reiter RJ. Breast cancer cells: Modulation by melatonin and the ubiquitin-proteasome system--a review. Mol Cell Endocrinol 2015; 417:1-9. [PMID: 26363225 DOI: 10.1016/j.mce.2015.09.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 09/01/2015] [Indexed: 02/07/2023]
Abstract
Melatonin inhibits human breast cancer cells stimulated with estrogen. This antiproliferative action depends on the presence of the estrogen receptor alpha (ERα) in the human MCF-7 cell line and is strictly dose-dependent. Since researchers concerned with melatonin and breast cancer have not considered the relevance of the ubiquitin-proteasome system to this research in this review we do so. The fact that the first breast cancer susceptibility gene to be identified, Brca1, functions as a ubiquitin ligase indicates that the ubiquitin-proteasome system has a role in regulating susceptibility to breast cancer. While mutations of this gene increase the incidence of breast cancer, the wild type gene suppresses estrogen-dependent transcriptional events relying on the estrogen receptor ERα. Three other ubiquitin ligases, SCF(Skp2), E6AP and APC, interact directly with ERα at the ERE and AP-1 promoters of ERα target genes. Melatonin, like proteasome inhibitors, decreases estrogen-induced gene transcription. Indeed, it has been reported that melatonin specifically inhibits estrogen-induced transcription mediated by ERα at the ERE and AP1 gene promoters. Herein, we present a model in which the inhibitory action of melatonin on MCF-7 cells is mediated, directly or indirectly, by the ubiquitin-proteasome system. In this model ERα, apoptotic proteins, and cell cycle proteins, all influenced by melatonin, are substrates of key ubiquitin ligases including SCF(Skp2), E6AP, and SCF(B-TrCP). Since dysfunction of the ubiquitin-proteasome system is a risk factor for breast cancer, this model provides a context in which to test the clinical potential, and limitations, of melatonin and proteasome inhibitors.
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Affiliation(s)
- Jerry Vriend
- Department of Human Anatomy and Cell Science, University of Manitoba, Winnipeg, MB, Canada.
| | - Russel J Reiter
- Department of Cellular and Structural Biology, UT Health Science Center San Antonio, TX, USA
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18
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Clarke R, Cook KL. Unfolding the Role of Stress Response Signaling in Endocrine Resistant Breast Cancers. Front Oncol 2015; 5:140. [PMID: 26157705 PMCID: PMC4475795 DOI: 10.3389/fonc.2015.00140] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2015] [Accepted: 06/03/2015] [Indexed: 11/24/2022] Open
Abstract
The unfolded protein response (UPR) is an ancient stress response that enables a cell to manage the energetic stress that accompanies protein folding. There has been a significant recent increase in our understanding of the UPR, how it integrates physiological processes within cells, and how this integration can affect cancer cells and cell fate decisions. Recent publications have highlighted the role of UPR signaling components on mediating various cell survival pathways, cellular metabolism and bioenergenics, and autophagy. We address the role of UPR on mediating endocrine therapy resistance and estrogen receptor-positive breast cancer cell survival.
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Affiliation(s)
- Robert Clarke
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center , Washington, DC , USA
| | - Katherine L Cook
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center , Washington, DC , USA
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19
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Cook KL, Schwartz-Roberts JL, Baumann WT, Clarke R. Linking autophagy with inflammation through IRF1 signaling in ER+ breast cancer. Mol Cell Oncol 2015; 3:e1023928. [PMID: 27308537 DOI: 10.1080/23723556.2015.1023928] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Revised: 02/21/2015] [Accepted: 02/23/2015] [Indexed: 10/23/2022]
Abstract
Resistance to antiestrogen therapy remains a critical determinant of mortality in patients affected by ER+ breast cancer. Our previous work identified autophagy and interferon regulatory factor 1 (IRF1) signaling as key regulators of this process. We have recently demonstrated a novel reciprocal interaction between IRF1 and ATG7, linking inflammation and autophagy.
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Affiliation(s)
- Katherine L Cook
- Department of Oncology and Lombardi Comprehensive Cancer Center; Georgetown University Medical Center, Washington, DC USA; Department of Surgery, Hypertension and Vascular Research Center, Wake Forest Comprehensive Cancer Center; Wake Forest University, Winston-Salem, NC USA
| | - Jessica L Schwartz-Roberts
- Department of Oncology and Lombardi Comprehensive Cancer Center; Georgetown University Medical Center , Washington, DC USA
| | - William T Baumann
- Bradley Department of Electrical and Computer Engineering Virginia Polytechnic Institute and State University , Blacksburg, VA USA
| | - Robert Clarke
- Department of Oncology and Lombardi Comprehensive Cancer Center; Georgetown University Medical Center , Washington, DC USA
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20
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Cook KL, Clarke R. Estrogen receptor-α signaling and localization regulates autophagy and unfolded protein response activation in ER+ breast cancer. ACTA ACUST UNITED AC 2014; 1. [PMID: 26005699 DOI: 10.14800/rci.316] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Antiestrogen therapy is commonly used to treat estrogen receptor (ER)+ breast cancers but acquired and de novo resistance limits their overall curative potential. An endoplasmic reticulum stress pathway, the unfolded protein response, and autophagy are both implicated in the development of antiestrogen therapy resistance in estrogen receptor-α (ER) positive breast cancer. Thus, we recently investigated how ERα can regulate autophagy and the unfolded protein response (Cook et al., FASEBJ, 2014). We showed that inhibiting ERα signaling stimulates autophagosome formation and flux. Moreover, we showed that ERα knockdown inhibited the unfolded protein response (UPR) signaling components. Here we support and extend this recent report showing additional data on ERα localization and provide a schematic of the overall signaling implicated by our results. Differential activation of UPR and autophagy highlight the pivotal role of ERα in regulating pro-survival signaling in breast cancer through UPR and autophagy. Furthermore, these data suggest new approaches to successful targeting ERα and preventing the regulation of key pro-survival signaling that confers resistance to endocrine therapies.
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Affiliation(s)
- Katherine L Cook
- Department of Oncology and Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC 20057, USA
| | - Robert Clarke
- Department of Oncology and Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC 20057, USA
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21
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Abstract
This review is intended to summarize the current knowledge from basic science and clinical medical literature cited within PubMed that pertain to gender-related factors and affect those individuals with hereditary ocular disorders. We consider gender-related biological factors that (a) affect disease onset and progression, (b) gender differences for major X-linked ocular disorders, (c) gender-specific conditions, (d) medications that may influence genetic eye disorders, and finally, (e) gender-related issues that influence the management and quality of life of these patients. Several studies have demonstrated the manner in which sex-related hormones in animal models are capable of influencing cell pathway and survival that are likely to affect hereditary eye disorders. There are very few clinical studies that provide compelling evidence for gender differences in human ocular conditions, other than for a number of X-linked disorders. Disease expression for X-linked disorders may be impacted by genetic mechanisms such as lyonization or uniparental disomy. Clinical evidence regarding the impact of gender-related medical conditions and therapies on eye conditions is extremely limited and primarily based on anecdotal evidence. Gender-specific factors may play a major role in the underlying biological pathways that influence the onset, rate of progression, and clinical findings associated with ocular genetic conditions. Clinicians need to be aware of the variable phenotypes observed in female carriers of X-linked disorders of gender specific issues, many of which are inadequately addressed in the current literature. Clinicians need to be sensitive to gender differences in social, cultural, and religious systems and they should also be aware of how their own gender biases may influence how they counsel patients. Finally, it is clear that the lack of effective clinical studies in this area creates an opportunity for future research that will have real benefits for these patients.
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22
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Cook KL, Clarke PAG, Parmar J, Hu R, Schwartz-Roberts JL, Abu-Asab M, Wärri A, Baumann WT, Clarke R. Knockdown of estrogen receptor-α induces autophagy and inhibits antiestrogen-mediated unfolded protein response activation, promoting ROS-induced breast cancer cell death. FASEB J 2014; 28:3891-905. [PMID: 24858277 DOI: 10.1096/fj.13-247353] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 05/12/2014] [Indexed: 01/08/2023]
Abstract
Approximately 70% of all newly diagnosed breast cancers express estrogen receptor (ER)-α. Although inhibiting ER action using targeted therapies such as fulvestrant (ICI) is often effective, later emergence of antiestrogen resistance limits clinical use. We used antiestrogen-sensitive and -resistant cells to determine the effect of antiestrogens/ERα on regulating autophagy and unfolded protein response (UPR) signaling. Knockdown of ERα significantly increased the sensitivity of LCC1 cells (sensitive) and also resensitized LCC9 cells (resistant) to antiestrogen drugs. Interestingly, ERα knockdown, but not ICI, reduced nuclear factor (erythroid-derived 2)-like (NRF)-2 (UPR-induced antioxidant protein) and increased cytosolic kelch-like ECH-associated protein (KEAP)-1 (NRF2 inhibitor), consistent with the observed increase in ROS production. Furthermore, autophagy induction by antiestrogens was prosurvival but did not prevent ERα knockdown-mediated death. We built a novel mathematical model to elucidate the interactions among UPR, autophagy, ER signaling, and ROS regulation of breast cancer cell survival. The experimentally validated mathematical model explains the counterintuitive result that knocking down the main target of ICI (ERα) increased the effectiveness of ICI. Specifically, the model indicated that ERα is no longer present in excess and that the effect on proliferation from further reductions in its level by ICI cannot be compensated for by increased autophagy. The stimulation of signaling that can confer resistance suggests that combining autophagy or UPR inhibitors with antiestrogens would reduce the development of resistance in some breast cancers.
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Affiliation(s)
- Katherine L Cook
- Department of Oncology and Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, District of Columbia, USA
| | - Pamela A G Clarke
- Department of Oncology and Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, District of Columbia, USA
| | | | - Rong Hu
- Department of Oncology and Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, District of Columbia, USA
| | - Jessica L Schwartz-Roberts
- Department of Oncology and Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, District of Columbia, USA
| | - Mones Abu-Asab
- Section of Immunopathology and Laboratory of Immunology, National Eye Institute, U.S. National Institutes of Health, Bethesda, Maryland, USA
| | - Anni Wärri
- Department of Oncology and Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, District of Columbia, USA
| | - William T Baumann
- Bradley Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA; and
| | - Robert Clarke
- Department of Oncology and Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, District of Columbia, USA;
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23
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Parmar JH, Cook KL, Shajahan-Haq AN, Clarke PAG, Tavassoly I, Clarke R, Tyson JJ, Baumann WT. Modelling the effect of GRP78 on anti-oestrogen sensitivity and resistance in breast cancer. Interface Focus 2014; 3:20130012. [PMID: 24511377 DOI: 10.1098/rsfs.2013.0012] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Understanding the origins of resistance to anti-oestrogen drugs is of critical importance to many breast cancer patients. Recent experiments show that knockdown of GRP78, a key gene in the unfolded protein response (UPR), can re-sensitize resistant cells to anti-oestrogens, and overexpression of GRP78 in sensitive cells can cause them to become resistant. These results appear to arise from the operation and interaction of three cellular systems: the UPR, autophagy and apoptosis. To determine whether our current mechanistic understanding of these systems is sufficient to explain the experimental results, we built a mathematical model of the three systems and their interactions. We show that the model is capable of reproducing previously published experimental results and some new data gathered specifically for this paper. The model provides us with a tool to better understand the interactions that bring about anti-oestrogen resistance and the effects of GRP78 on both sensitive and resistant breast cancer cells.
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Affiliation(s)
- Jignesh H Parmar
- Department of Biological Sciences , Virginia Polytechnic Institute and State University , Blacksburg, VA 24061 , USA
| | - Katherine L Cook
- Department of Oncology, Lombardi Comprehensive Cancer Center , Georgetown University Medical Center , Washington, DC 20057 , USA
| | - Ayesha N Shajahan-Haq
- Department of Oncology, Lombardi Comprehensive Cancer Center , Georgetown University Medical Center , Washington, DC 20057 , USA
| | - Pamela A G Clarke
- Department of Oncology, Lombardi Comprehensive Cancer Center , Georgetown University Medical Center , Washington, DC 20057 , USA
| | - Iman Tavassoly
- Department of Biological Sciences , Virginia Polytechnic Institute and State University , Blacksburg, VA 24061 , USA
| | - Robert Clarke
- Department of Oncology, Lombardi Comprehensive Cancer Center , Georgetown University Medical Center , Washington, DC 20057 , USA
| | - John J Tyson
- Department of Biological Sciences , Virginia Polytechnic Institute and State University , Blacksburg, VA 24061 , USA
| | - William T Baumann
- Bradley Department of Electrical and Computer Engineering , Virginia Polytechnic Institute and State University , Blacksburg, VA 24061 , USA
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24
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Dull AB, George AA, Goncharova EI, Evans JR, Wamiru A, Cartner LK, Hager GL, McMahon JB. Identification of compounds by high-content screening that induce cytoplasmic to nuclear localization of a fluorescent estrogen receptor α chimera and exhibit agonist or antagonist activity in vitro. ACTA ACUST UNITED AC 2013; 19:242-52. [PMID: 24051224 DOI: 10.1177/1087057113504136] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We have completed a robust high-content imaging screen for novel estrogen receptor α (ERα) agonists and antagonists by quantitation of cytoplasmic to nuclear translocation of an estrogen receptor chimera in 384-well plates. The screen was very robust, with Z' values >0.7 and coefficients of variation (CV) <5%. The screen utilized a stably transfected green fluorescent protein-tagged glucocorticoid/estrogen receptor (GFP-GRER) chimera, which consisted of the N-terminus of the glucocorticoid receptor fused to the human ERα ligand binding domain. The GFP-GRER exhibited cytoplasmic localization in the absence of ERα ligands and translocated to the nucleus in response to stimulation with ERα agonists and antagonists. The BD Pathway 435 imaging system was used for image acquisition, analysis of translocation dynamics, and cytotoxicity measurements. We screened 224,891 samples from our synthetic, pure natural product libraries, prefractionated natural product extracts library, and crude natural product extracts library, which produced a 0.003% hit rate. In addition to identifying several known ER ligands, five compounds were discovered that elicited significant activity in the screen. Transactivation potential studies demonstrated that two hit compounds behave as agonists, while three compounds elicited antagonist activity in MCF-7 cells.
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Affiliation(s)
- Angie B Dull
- 1SAIC-Frederick, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD, USA
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Zhang L, Cui J, Leonard M, Nephew K, Li Y, Zhang X. Silencing MED1 sensitizes breast cancer cells to pure anti-estrogen fulvestrant in vitro and in vivo. PLoS One 2013; 8:e70641. [PMID: 23936234 PMCID: PMC3728322 DOI: 10.1371/journal.pone.0070641] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Accepted: 06/19/2013] [Indexed: 12/21/2022] Open
Abstract
Pure anti-estrogen fulvestrant has been shown to be a promising ER antagonist for locally advanced and metastatic breast cancer. Unfortunately, a significant proportion of patients developed resistance to this type of endocrine therapy but the molecular mechanisms governing cellular responsiveness to this agent remain poorly understood. Here, we’ve reported that knockdown of estrogen receptor coactivator MED1 sensitized fulvestrant resistance breast cancer cells to fulvestrant treatment. We found that MED1 knockdown further promoted cell cycle arrest induced by fulvestrant. Using an orthotopic xenograft mouse model, we found that knockdown of MED1 significantly reduced tumor growth in mice. Importantly, knockdown of MED1 further potentiated tumor growth inhibition by fulvestrant. Mechanistic studies indicated that combination of fulvestrant treatment and MED1 knockdown is able to cooperatively inhibit the expression of ER target genes. Chromatin immunoprecipitation experiments further supported a role for MED1 in regulating the recruitment of RNA polymerase II and transcriptional corepressor HDAC1 on endogenous ER target gene promoter in the presence of fulvestrant. These results demonstrate a role for MED1 in mediating resistance to the pure anti-estrogen fulvestrant both in vitro and in vivo.
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Affiliation(s)
- Lijiang Zhang
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
- Institute of Biochemistry, College of Life Science, Zhejiang University, Hangzhou City, China
- Center of Safety Evaluation, Zhejiang Academy of Medical Sciences, Hangzhou City, China
| | - Jiajun Cui
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Marissa Leonard
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Kenneth Nephew
- Department of Medical Sciences, Indiana University School of Medicine, Bloomington, Indiana, United States of America
| | - Yongquan Li
- Institute of Biochemistry, College of Life Science, Zhejiang University, Hangzhou City, China
- * E-mail: (XZ); (YL)
| | - Xiaoting Zhang
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
- * E-mail: (XZ); (YL)
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Yeh WL, Shioda K, Coser KR, Rivizzigno D, McSweeney KR, Shioda T. Fulvestrant-induced cell death and proteasomal degradation of estrogen receptor α protein in MCF-7 cells require the CSK c-Src tyrosine kinase. PLoS One 2013; 8:e60889. [PMID: 23593342 PMCID: PMC3617152 DOI: 10.1371/journal.pone.0060889] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Accepted: 03/06/2013] [Indexed: 12/19/2022] Open
Abstract
Fulvestrant is a representative pure antiestrogen and a Selective Estrogen Receptor Down-regulator (SERD). In contrast to the Selective Estrogen Receptor Modulators (SERMs) such as 4-hydroxytamoxifen that bind to estrogen receptor α (ERα) as antagonists or partial agonists, fulvestrant causes proteasomal degradation of ERα protein, shutting down the estrogen signaling to induce proliferation arrest and apoptosis of estrogen-dependent breast cancer cells. We performed genome-wide RNAi knockdown screenings for protein kinases required for fulvestrant-induced apoptosis of the MCF-7 estrogen-dependent human breast caner cells and identified the c-Src tyrosine kinase (CSK), a negative regulator of the oncoprotein c-Src and related protein tyrosine kinases, as one of the necessary molecules. Whereas RNAi knockdown of CSK in MCF-7 cells by shRNA-expressing lentiviruses strongly suppressed fulvestrant-induced cell death, CSK knockdown did not affect cytocidal actions of 4-hydroxytamoxifen or paclitaxel, a chemotherapeutic agent. In the absence of CSK, fulvestrant-induced proteasomal degradation of ERα protein was suppressed in both MCF-7 and T47D estrogen-dependent breast cancer cells whereas the TP53-mutated T47D cells were resistant to the cytocidal action of fulvestrant in the presence or absence of CSK. MCF-7 cell sensitivities to fulvestrant-induced cell death or ERα protein degradation was not affected by small-molecular-weight inhibitors of the tyrosine kinase activity of c-Src, suggesting possible involvement of other signaling molecules in CSK-dependent MCF-7 cell death induced by fulvestrant. Our observations suggest the importance of CSK in the determination of cellular sensitivity to the cytocidal action of fulvestrant.
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Affiliation(s)
- Wei-Lan Yeh
- Center for Cancer Research, Massachusetts General Hospital Cancer Center and Harvard Medical School, Charlestown, Massachusetts, United States of America
| | - Keiko Shioda
- Center for Cancer Research, Massachusetts General Hospital Cancer Center and Harvard Medical School, Charlestown, Massachusetts, United States of America
| | - Kathryn R. Coser
- Center for Cancer Research, Massachusetts General Hospital Cancer Center and Harvard Medical School, Charlestown, Massachusetts, United States of America
| | - Danielle Rivizzigno
- Center for Cancer Research, Massachusetts General Hospital Cancer Center and Harvard Medical School, Charlestown, Massachusetts, United States of America
| | - Kristen R. McSweeney
- Center for Cancer Research, Massachusetts General Hospital Cancer Center and Harvard Medical School, Charlestown, Massachusetts, United States of America
| | - Toshi Shioda
- Center for Cancer Research, Massachusetts General Hospital Cancer Center and Harvard Medical School, Charlestown, Massachusetts, United States of America
- * E-mail:
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27
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Komatsu S, Miyazawa K, Moriya S, Takase A, Naito M, Inazu M, Kohno N, Itoh M, Tomoda A. Clarithromycin enhances bortezomib-induced cytotoxicity via endoplasmic reticulum stress-mediated CHOP (GADD153) induction and autophagy in breast cancer cells. Int J Oncol 2011; 40:1029-39. [PMID: 22200786 PMCID: PMC3584821 DOI: 10.3892/ijo.2011.1317] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2011] [Accepted: 11/28/2011] [Indexed: 12/29/2022] Open
Abstract
The specific 26S proteasome inhibitor, bortezomib (BZ) potently induces apoptosis as well as autophagy in metastatic breast cancer cell lines such as MDA-MB-231 and MDA-MB-468. The combined treatment of clarithromycin (CAM) and BZ significantly enhances cytotoxicity in these cell lines. Although treatment with up to 100 μg/ml CAM alone had little effect on cell growth inhibition, the accumulation of autophagosomes and p62 was observed after treatment with 25 μg/ml CAM. This result indicated that CAM blocked autophagy flux. However, the combined treatment of BZ and CAM resulted in more pronounced autophagy induction, as assessed by increased expression ratios of LC3B-II to LC3B-I and clearance of intracellular p62, than treatment with BZ alone. This combination further enhanced induction of the pro-apoptotic transcription factor CHOP (CADD153) and the chaperone protein GRP78. Knockdown of CHOP by siRNA attenuated the death-promoting effect of BZ in MDA-MB-231 cells. A wild-type murine embryonic fibroblast (MEF) cell line also exhibited enhanced BZ-induced cytotoxicity with the addition of CAM, whereas a Chop knockout MEF cell line completely abolished this enhancement and exhibited resistance to BZ treatment. These data suggest that endoplasmic reticulum (ER)-stress mediated CHOP induction is involved in pronounced cytotoxicity by combining these reagents. Simultaneously targeting two major intracellular protein degradation pathways such as the ubiquitin-proteasome system by BZ and the autophagy-lysosome pathway by CAM may improve the therapeutic outcome in breast cancer patients via ER-stress mediated apoptosis.
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Affiliation(s)
- Seiichiro Komatsu
- Department of Breast Oncology, Tokyo Medical University, Tokyo 160-8402, Japan
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28
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Prenzel T, Begus-Nahrmann Y, Kramer F, Hennion M, Hsu C, Gorsler T, Hintermair C, Eick D, Kremmer E, Simons M, Beissbarth T, Johnsen SA. Estrogen-dependent gene transcription in human breast cancer cells relies upon proteasome-dependent monoubiquitination of histone H2B. Cancer Res 2011; 71:5739-53. [PMID: 21862633 DOI: 10.1158/0008-5472.can-11-1896] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The estrogen receptor-α (ERα) determines the phenotype of breast cancers where it serves as a positive prognostic indicator. ERα is a well-established target for breast cancer therapy, but strategies to target its function remain of interest to address therapeutic resistance and further improve treatment. Recent findings indicate that proteasome inhibition can regulate estrogen-induced transcription, but how ERα function might be regulated was uncertain. In this study, we investigated the transcriptome-wide effects of the proteasome inhibitor bortezomib on estrogen-regulated transcription in MCF7 human breast cancer cells and showed that bortezomib caused a specific global decrease in estrogen-induced gene expression. This effect was specific because gene expression induced by the glucocorticoid receptor was unaffected by bortezomib. Surprisingly, we observed no changes in ERα recruitment or assembly of its transcriptional activation complex on ERα target genes. Instead, we found that proteasome inhibition caused a global decrease in histone H2B monoubiquitination (H2Bub1), leading to transcriptional elongation defects on estrogen target genes and to decreased chromatin dynamics overall. In confirming the functional significance of this link, we showed that RNA interference-mediated knockdown of the H2B ubiquitin ligase RNF40 decreased ERα-induced gene transcription. Surprisingly, RNF40 knockdown also supported estrogen-independent cell proliferation and activation of cell survival signaling pathways. Most importantly, we found that H2Bub1 levels decrease during tumor progression. H2Bub1 was abundant in normal mammary epithelium and benign breast tumors but absent in most malignant and metastatic breast cancers. Taken together, our findings show how ERα activity is blunted by bortezomib treatment as a result of reducing the downstream ubiquitin-dependent function of H2Bub1. In supporting a tumor suppressor role for H2Bub1 in breast cancer, our findings offer a rational basis to pursue H2Bub1-based therapies for future management of breast cancer.
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Affiliation(s)
- Tanja Prenzel
- Department of Molecular Oncology, Göttingen Center for Molecular Biosciences, Department of Medical Statistics, University Medical Center Göttingen, Germany
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Abstract
By eliciting distinct transcriptional responses, the oestrogen receptors (ERs) ERα and ERβ exert opposite effects on cellular processes that include proliferation, apoptosis and migration and that differentially influence the development and the progression of cancer. Perturbation of ER subtype-specific expression has been detected in various types of cancer, and the differences in the expression of ERs are correlated with the clinical outcome. The changes in the bioavailability of ERs in tumours, together with their specific biological functions, promote the selective restoration of their activity as one of the major therapeutic approaches for hormone-dependent cancers.
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Affiliation(s)
- Christoforos Thomas
- Center for Nuclear Receptors and Cell Signalling, Department of Biology and Biochemistry, University of Houston, Houston 77204, Texas, USA
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Liu J, Zhan YH, Liu YP, Qu XJ, Xu L, Zhang Y, Hou KZ, Hu XJ. In vitro antitumor effect of the proteasome inhibitor bortezomib on human gastric cancer SGC7901 cells. Shijie Huaren Xiaohua Zazhi 2011; 19:1441-1445. [DOI: 10.11569/wcjd.v19.i14.1441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate the anti-tumor effect of bortezomib, a proteasome inhibitor, on human gastric cancer SGC7901 cells and to explore possible mechanism involved.
METHODS: Human gastric cancer SGC7901 cells were cultured and treated with different concentrations of bortezomib (1-500 nmol/L) for 24-48 h. Cell viability was determined by MTT assay. Apoptosis was detected by flow cytometry. The cleavage of PARP and caspase-3 and level of phosphor-Akt were determined by Western blot.
RESULTS: Bortezomib inhibited the viability of SGC7901 cells in a dose- and time-dependent manner. The IC50 value at 48 h was 67.39 nmol/L. Treatment with 60 or 180 nmol/L of bortezomib induced cell cycle arrest at G2/M phase at both 24 and 48 h but induced apoptosis only at 48 h. The cleavage of caspase-3 and PARP was observed in cells treated with 60 or 180 nmol/L of bortezomib for 48 h. Treatment with bortezomib for 48 h down-regulated the level of phosphor-Akt in SGC7901 cells.
CONCLUSION: Bortezomib induced apoptosis and cell cycle arrest at G2/M phase by inhibiting the activity of the PI3K/Akt signaling pathway in human gastric cancer SGC7901 cells.
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