51
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Castagnoli L, Ghedini GC, Koschorke A, Triulzi T, Dugo M, Gasparini P, Casalini P, Palladini A, Iezzi M, Lamolinara A, Lollini PL, Nanni P, Chiodoni C, Tagliabue E, Pupa SM. Pathobiological implications of the d16HER2 splice variant for stemness and aggressiveness of HER2-positive breast cancer. Oncogene 2016; 36:1721-1732. [PMID: 27641338 PMCID: PMC5447867 DOI: 10.1038/onc.2016.338] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 08/05/2016] [Indexed: 12/21/2022]
Abstract
We have previously shown that the d16HER2 splice variant is linked to HER2-positive
breast cancer (BC) tumorigenesis, progression and response to Trastuzumab. However,
the mechanisms by which d16HER2 contributes to HER2-driven aggressiveness and
targeted therapy susceptibility remain uncertain. Here, we report that the
d16HER2-positive mammary tumor cell lines MI6 and MI7, derived from spontaneous
lesions of d16HER2 transgenic (tg) mice and resembling the aggressive features of
primary lesions, are enriched in the expression of Wnt, Notch and
epithelial–mesenchymal transition pathways related genes compared with
full-length wild-type (WT) HER2-positive cells (WTHER2_1 and WTHER2_2) derived from
spontaneous tumors arising in WTHER2 tg mice. MI6 cells exhibited increased
resistance to anoikis and significantly higher mammosphere-forming efficiency (MFE)
and self-renewal capability than the WTHER2-positive counterpart. Furthermore,
d16HER2-positive tumor cells expressed a higher fraction of
CD29High/CD24+/SCA1Low cells and
displayed greater in vivo tumor engraftment in serial dilution conditions
than WTHER2_1 cells. Accordingly, NOTCH inhibitors impaired mammosphere formation
only in MI6 cells. A comparative analysis of stemness-related features driven by
d16HER2 and WTHER2 in ad hoc engineered human BC cells (MCF7 and T47D)
revealed a higher MFE and aldehyde dehydrogenase-positive staining in d16HER2- vs
WTHER2-infected cells, sustaining consistent BC-initiating cell enrichment in the
human setting. Moreover, marked CD44 expression was found in MCF7_d16 and T47D_d16
cells vs their WTHER2 and Mock counterparts. Clinically, BC cases from two distinct
HER2-positive cohorts characterized by high levels of expression of the
activated-d16HER2 metagene were significantly enriched in the Notch family and signal
transducer genes vs those with low levels of the metagene.
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Affiliation(s)
- L Castagnoli
- Molecular Targeting Unit, Department of Experimental Oncology and Molecular Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - G C Ghedini
- Molecular Targeting Unit, Department of Experimental Oncology and Molecular Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - A Koschorke
- Molecular Targeting Unit, Department of Experimental Oncology and Molecular Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - T Triulzi
- Molecular Targeting Unit, Department of Experimental Oncology and Molecular Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - M Dugo
- Functional Genomics and Bioinformatics Core Facility, Department of Experimental Oncology and Molecular Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - P Gasparini
- Tumor Genomics Unit, Department of Experimental Oncology and Molecular Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - P Casalini
- Molecular Targeting Unit, Department of Experimental Oncology and Molecular Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - A Palladini
- Laboratory of Immunology and Biology of Metastases, Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Bologna, Italy
| | - M Iezzi
- CESI Aging Research Center, Department of Medicine and Aging Sciences, G D'Annunzio University, Via Colle dell'Ara, Chieti Scalo, Chieti, Italy
| | - A Lamolinara
- CESI Aging Research Center, Department of Medicine and Aging Sciences, G D'Annunzio University, Via Colle dell'Ara, Chieti Scalo, Chieti, Italy
| | - P L Lollini
- Laboratory of Immunology and Biology of Metastases, Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Bologna, Italy
| | - P Nanni
- Laboratory of Immunology and Biology of Metastases, Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Bologna, Italy
| | - C Chiodoni
- Molecular Immunology Unit, Department of Experimental Oncology and Molecular Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - E Tagliabue
- Molecular Targeting Unit, Department of Experimental Oncology and Molecular Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - S M Pupa
- Molecular Targeting Unit, Department of Experimental Oncology and Molecular Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
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Wicki A, Mandalà M, Massi D, Taverna D, Tang H, Hemmings BA, Xue G. Acquired Resistance to Clinical Cancer Therapy: A Twist in Physiological Signaling. Physiol Rev 2016; 96:805-29. [DOI: 10.1152/physrev.00024.2015] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Although modern therapeutic strategies have brought significant progress to cancer care in the last 30 years, drug resistance to targeted monotherapies has emerged as a major challenge. Aberrant regulation of multiple physiological signaling pathways indispensable for developmental and metabolic homeostasis, such as hyperactivation of pro-survival signaling axes, loss of suppressive regulations, and impaired functionalities of the immune system, have been extensively investigated aiming to understand the diversity of molecular mechanisms that underlie cancer development and progression. In this review, we intend to discuss the molecular mechanisms of how conventional physiological signal transduction confers to acquired drug resistance in cancer patients. We will particularly focus on protooncogenic receptor kinase inhibition-elicited tumor cell adaptation through two major core downstream signaling cascades, the PI3K/Akt and MAPK pathways. These pathways are crucial for cell growth and differentiation and are frequently hyperactivated during tumorigenesis. In addition, we also emphasize the emerging roles of the deregulated host immune system that may actively promote cancer progression and attenuate immunosurveillance in cancer therapies. Understanding these mechanisms may help to develop more effective therapeutic strategies that are able to keep the tumor in check and even possibly turn cancer into a chronic disease.
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Affiliation(s)
- Andreas Wicki
- Department of Biomedicine, University Hospital Basel, Basel, Switzerland; Department of Oncology and Hematology, Papa Giovanni XXIII Hospital, Bergamo, Italy; Department of Surgery and Translational Medicine, University of Florence, Florence, Italy; Department of Molecular Biotechnology and Health Sciences, University of Turin, Torino, Italy; Department of Pharmacology, Zhejiang University School of Medicine, Hangzhou, China; and Department of Mechanisms of Cancer, Friedrich Miescher Institute for
| | - Mario Mandalà
- Department of Biomedicine, University Hospital Basel, Basel, Switzerland; Department of Oncology and Hematology, Papa Giovanni XXIII Hospital, Bergamo, Italy; Department of Surgery and Translational Medicine, University of Florence, Florence, Italy; Department of Molecular Biotechnology and Health Sciences, University of Turin, Torino, Italy; Department of Pharmacology, Zhejiang University School of Medicine, Hangzhou, China; and Department of Mechanisms of Cancer, Friedrich Miescher Institute for
| | - Daniela Massi
- Department of Biomedicine, University Hospital Basel, Basel, Switzerland; Department of Oncology and Hematology, Papa Giovanni XXIII Hospital, Bergamo, Italy; Department of Surgery and Translational Medicine, University of Florence, Florence, Italy; Department of Molecular Biotechnology and Health Sciences, University of Turin, Torino, Italy; Department of Pharmacology, Zhejiang University School of Medicine, Hangzhou, China; and Department of Mechanisms of Cancer, Friedrich Miescher Institute for
| | - Daniela Taverna
- Department of Biomedicine, University Hospital Basel, Basel, Switzerland; Department of Oncology and Hematology, Papa Giovanni XXIII Hospital, Bergamo, Italy; Department of Surgery and Translational Medicine, University of Florence, Florence, Italy; Department of Molecular Biotechnology and Health Sciences, University of Turin, Torino, Italy; Department of Pharmacology, Zhejiang University School of Medicine, Hangzhou, China; and Department of Mechanisms of Cancer, Friedrich Miescher Institute for
| | - Huifang Tang
- Department of Biomedicine, University Hospital Basel, Basel, Switzerland; Department of Oncology and Hematology, Papa Giovanni XXIII Hospital, Bergamo, Italy; Department of Surgery and Translational Medicine, University of Florence, Florence, Italy; Department of Molecular Biotechnology and Health Sciences, University of Turin, Torino, Italy; Department of Pharmacology, Zhejiang University School of Medicine, Hangzhou, China; and Department of Mechanisms of Cancer, Friedrich Miescher Institute for
| | - Brian A. Hemmings
- Department of Biomedicine, University Hospital Basel, Basel, Switzerland; Department of Oncology and Hematology, Papa Giovanni XXIII Hospital, Bergamo, Italy; Department of Surgery and Translational Medicine, University of Florence, Florence, Italy; Department of Molecular Biotechnology and Health Sciences, University of Turin, Torino, Italy; Department of Pharmacology, Zhejiang University School of Medicine, Hangzhou, China; and Department of Mechanisms of Cancer, Friedrich Miescher Institute for
| | - Gongda Xue
- Department of Biomedicine, University Hospital Basel, Basel, Switzerland; Department of Oncology and Hematology, Papa Giovanni XXIII Hospital, Bergamo, Italy; Department of Surgery and Translational Medicine, University of Florence, Florence, Italy; Department of Molecular Biotechnology and Health Sciences, University of Turin, Torino, Italy; Department of Pharmacology, Zhejiang University School of Medicine, Hangzhou, China; and Department of Mechanisms of Cancer, Friedrich Miescher Institute for
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53
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Ross JS, Gay LM, Wang K, Ali SM, Chumsri S, Elvin JA, Bose R, Vergilio JA, Suh J, Yelensky R, Lipson D, Chmielecki J, Waintraub S, Leyland-Jones B, Miller VA, Stephens PJ. Nonamplification ERBB2 genomic alterations in 5605 cases of recurrent and metastatic breast cancer: An emerging opportunity for anti-HER2 targeted therapies. Cancer 2016; 122:2654-62. [PMID: 27284958 DOI: 10.1002/cncr.30102] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 03/21/2016] [Accepted: 04/01/2016] [Indexed: 01/10/2023]
Abstract
BACKGROUND Activating, nonamplification ERBB2 mutations (ERBB2mut) are not detected by immunohistochemistry (IHC) or fluorescence in situ hybridization (FISH), but are detected by DNA sequencing and may predict clinical responses to human epidermal growth factor receptor (HER2)-targeted therapy. The authors queried 5605 advanced/metastatic breast cancers (mBC) to uncover the frequency of ERBB2mut genomic alterations. Clinical responses to anti-HER2 therapeutics were identified. METHODS DNA was extracted from 40 µm of formalin-fixed paraffin-embedded (FFPE) sections. Comprehensive genomic profiling (CGP) was used to evaluate up to 315 genes (592× mean coverage depth). Results were analyzed for base substitutions, short indels, copy number changes, and selected rearrangements. RESULTS Of 5605 cases, 698 (12.5%) featured ERBB2 alterations, including 596 (10.6%) ERBB2 amplifications (ERBB2amp) and 138 (2.4%) ERBB2mut; 38 cases (0.7%) had co-occurring ERBB2amp and ERBB2mut. ERBB2mut predominantly affected the kinase (124 cases; 90%) or extracellular (15 cases; 11%) domains. Both primary BC (52 cases; 38%) and metastatic site biopsies (86 cases; 62%) were found to harbor ERBB2mut, which were distributed across carcinoma not otherwise specified (NOS) (69 cases; 50%), invasive ductal carcinoma (IDC) (40 cases; 29%), invasive lobular carcinoma (ILC) (27 cases; 20%), and mucinous mBC (2 cases; 1%). Genes commonly coaltered with ERBB2 were tumor protein 53 (TP53) (49%); phosphatidylinositol 3-kinase catalytic subunit alpha (PIK3CA) (42%); cadherin 1, type 1 (CDH1) (37%); MYC (17%); and cyclin D1 protein (CCND1) (16%). CDH1 mutations were enriched in ERBB2mut mBC (P<0.0006) and associated with recurrent mBC. Selected patients with ERBB2mut, without ERBB2amp, who responded to anti-HER2 targeted therapies are presented herein. CONCLUSIONS Within this large series, 1.8% of cases harbored ERBB2mut, which are undetectable by standard-of-care IHC or FISH tests. Metastatic BC driven by ERBB2mut respond to anti-HER2 targeted therapies, and expanding clinical trials designed to detect ERBB2mut by CGP and optimize targeted treatments are warranted. Cancer 2016. © 2016 American Cancer Society. Cancer 2016;122:2654-2662. © 2016 American Cancer Society.
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Affiliation(s)
- Jeffrey S Ross
- Foundation Medicine Inc, Cambridge, Massachusetts.,Department of Pathology, Albany Medical College, Albany, New York
| | - Laurie M Gay
- Foundation Medicine Inc, Cambridge, Massachusetts
| | - Kai Wang
- Foundation Medicine Inc, Cambridge, Massachusetts.,Department of Computational Biology, Zhejiang Cancer Hospital, Hangzhou, China
| | - Siraj M Ali
- Foundation Medicine Inc, Cambridge, Massachusetts
| | - Saranya Chumsri
- Department of Hematology/Oncology, Mayo Clinic, Jacksonville, Florida
| | | | - Ron Bose
- Division of Oncology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri
| | | | - James Suh
- Foundation Medicine Inc, Cambridge, Massachusetts
| | | | - Doron Lipson
- Foundation Medicine Inc, Cambridge, Massachusetts
| | | | - Stanley Waintraub
- Department of Breast Oncology, Hackensack University Medical Center, Hackensack, New Jersey
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54
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Triulzi T, Bianchi GV, Tagliabue E. Predictive biomarkers in the treatment of HER2-positive breast cancer: an ongoing challenge. Future Oncol 2016; 12:1413-28. [DOI: 10.2217/fon-2015-0025] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The transmembrane tyrosine kinase receptor HER2 is overexpressed in 20% of invasive breast cancers and is associated with more aggressive disease. Until the advent of targeted agents, HER2 was associated with worse outcome. Trastuzumab, a recombinant humanized anti-HER2 monoclonal antibody, combined with chemotherapy improves disease-free and overall survival in both primary and metastatic tumors and represents a foundation of care for patients with HER2-positive breast cancers. However, a sizeable number of patients do not respond to this reagent, indicating the need for a biomarker able to recognize resistant tumors. Here, we review various studies on mechanisms of action and resistance to trastuzumab that have proven relevant in understanding how tumor care can be tailored to all HER2-positive patients.
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Affiliation(s)
- Tiziana Triulzi
- Molecular Targeting Unit, Department of Experimental Oncology & Molecular Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - Giulia Valeria Bianchi
- Department of Medical Oncology, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - Elda Tagliabue
- Molecular Targeting Unit, Department of Experimental Oncology & Molecular Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
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55
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The ErbB2ΔEx16 splice variant is a major oncogenic driver in breast cancer that promotes a pro-metastatic tumor microenvironment. Oncogene 2016; 35:6053-6064. [PMID: 27157621 PMCID: PMC5102823 DOI: 10.1038/onc.2016.129] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Revised: 03/04/2016] [Accepted: 03/11/2016] [Indexed: 01/09/2023]
Abstract
Amplification and over expression of erbB2/neu proto-oncogene is observed in 20–30% human breast cancer and is inversely correlated with the survival of the patient. Despite this, somatic activating mutations within erbB2 in human breast cancers are rare. However, we have previously reported that a splice isoform of erbB2, containing an in-frame deletion of exon 16 (herein referred to as ErbB2ΔEx16), results in oncogenic activation of erbB2 due to constitutive dimerization of the ErbB2 receptor. Here, we demonstrate that the ErbB2ΔEx16 is a major oncogenic driver in breast cancer that constitutively signals from the cell surface. We further show that inducible expression of the ErbB2Ex16 variant in mammary gland of transgenic mice results in the rapid development of metastatic multifocal mammary tumors. Genetic and biochemical characterization of the ErbB2ΔEx16 derived mammary tumors exhibit several unique features that distinguish it from the conventional ErbB2 models expressing the erbB2 proto-oncogene in mammary epithelium. Unlike the wild-type ErbB2 derived tumors that express luminal keratins, ErbB2ΔEx16 derived tumors exhibit high degree of intra-tumoral heterogeneity co-expressing both basal and luminal keratins. Consistent with these distinct pathological features, the ErbB2ΔEx16 tumors exhibited distinct signaling and gene expression profiles that correlated with activation of number of key transcription factors implicated in breast cancer metastasis and cancer stem cell renewal.
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56
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Ha JR, Siegel PM, Ursini-Siegel J. The Tyrosine Kinome Dictates Breast Cancer Heterogeneity and Therapeutic Responsiveness. J Cell Biochem 2016; 117:1971-90. [PMID: 27392311 DOI: 10.1002/jcb.25561] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 03/24/2016] [Indexed: 12/13/2022]
Abstract
Phospho-tyrosine signaling networks control numerous biological processes including cellular differentiation, cell growth and survival, motility, and invasion. Aberrant regulation of the tyrosine kinome is a hallmark of malignancy and influences all stages of breast cancer progression, from initiation to the development of metastatic disease. The success of specific tyrosine kinase inhibitors strongly validates the clinical relevance of tyrosine phosphorylation networks in breast cancer pathology. However, a significant degree of redundancy exists within the tyrosine kinome. Numerous receptor and cytoplasmic tyrosine kinases converge on a core set of signaling regulators, including adaptor proteins and tyrosine phosphatases, to amplify pro-tumorigenic signal transduction pathways. Mutational activation, amplification, or overexpression of one or more components of the tyrosine kinome represents key contributing events responsible for the tumor heterogeneity that is observed in breast cancers. It is this molecular heterogeneity that has become the most significant barrier to durable clinical responses due to the development of therapeutic resistance. This review focuses on recent literature that supports a prominent role for specific components of the tyrosine kinome in the emergence of unique breast cancer subtypes and in shaping breast cancer plasticity, sensitivity to targeted therapies, and the eventual emergence of acquired resistance. J. Cell. Biochem. 117: 1971-1990, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Jacqueline R Ha
- Lady Davis Institute for Medical Research, Montreal, Quebec, Canada.,Department of Medicine, McGill University, Montreal, Quebec, Canada.,Department of Oncology, McGill University, Montreal, Quebec, Canada
| | - Peter M Siegel
- Department of Medicine, McGill University, Montreal, Quebec, Canada.,Department of Oncology, McGill University, Montreal, Quebec, Canada.,Goodman Cancer Research Centre, McGill University, Montreal, Quebec, Canada.,Department of Biochemistry, McGill University, Montreal, Quebec, Canada.,Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada
| | - Josie Ursini-Siegel
- Lady Davis Institute for Medical Research, Montreal, Quebec, Canada.,Department of Medicine, McGill University, Montreal, Quebec, Canada.,Department of Oncology, McGill University, Montreal, Quebec, Canada
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57
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Gu S, Hu Z, Ngamcherdtrakul W, Castro DJ, Morry J, Reda MM, Gray JW, Yantasee W. Therapeutic siRNA for drug-resistant HER2-positive breast cancer. Oncotarget 2016; 7:14727-41. [PMID: 26894975 PMCID: PMC4924747 DOI: 10.18632/oncotarget.7409] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 01/30/2016] [Indexed: 01/18/2023] Open
Abstract
HER2 is overexpressed in about 20% of breast cancers and contributes to poor prognosis. Unfortunately, a large fraction of patients have primary or acquired resistance to the HER2-targeted therapy trastuzumab, thus a multi-drug combination is utilized in the clinic, putting significant burden on patients. We systematically identified an optimal HER2 siRNA from 76 potential sequences and demonstrated its utility in overcoming intrinsic and acquired resistance to trastuzumab and lapatinib in 18 HER2-positive cancer cell lines. We provided evidence that the drug-resistant cancer maintains dependence on HER2 for survival. Importantly, cell lines did not readily develop resistance following extended treatment with HER2 siRNA. Using our recently developed nanoparticle platform, systemic delivery of HER2 siRNA to trastuzumab-resistant tumors resulted in significant growth inhibition. Moreover, the optimal HER2 siRNA could also silence an exon 16 skipped HER2 splice variant reported to be highly oncogenic and linked to trastuzumab resistance.
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Affiliation(s)
- Shenda Gu
- Department of Biomedical Engineering, Oregon Health & Science University, Portland, Oregon, 97239, USA
| | - Zhi Hu
- Department of Biomedical Engineering, Oregon Health & Science University, Portland, Oregon, 97239, USA
| | - Worapol Ngamcherdtrakul
- Department of Biomedical Engineering, Oregon Health & Science University, Portland, Oregon, 97239, USA
- PDX Pharmaceuticals, LLC, Portland, Oregon, 97239, USA
| | - David J. Castro
- Department of Biomedical Engineering, Oregon Health & Science University, Portland, Oregon, 97239, USA
- PDX Pharmaceuticals, LLC, Portland, Oregon, 97239, USA
| | - Jingga Morry
- Department of Biomedical Engineering, Oregon Health & Science University, Portland, Oregon, 97239, USA
| | - Moataz M. Reda
- Department of Biomedical Engineering, Oregon Health & Science University, Portland, Oregon, 97239, USA
| | - Joe W. Gray
- Department of Biomedical Engineering, Oregon Health & Science University, Portland, Oregon, 97239, USA
| | - Wassana Yantasee
- Department of Biomedical Engineering, Oregon Health & Science University, Portland, Oregon, 97239, USA
- PDX Pharmaceuticals, LLC, Portland, Oregon, 97239, USA
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58
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Zambrano J, Yeh ES. Autophagy and Apoptotic Crosstalk: Mechanism of Therapeutic Resistance in HER2-Positive Breast Cancer. BREAST CANCER-BASIC AND CLINICAL RESEARCH 2016; 10:13-23. [PMID: 26997868 PMCID: PMC4790584 DOI: 10.4137/bcbcr.s32791] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 02/03/2016] [Accepted: 02/05/2016] [Indexed: 12/16/2022]
Abstract
While breast cancer patients benefit from the use of HER2 inhibitors, many fail therapy and become resistant to treatment, indicating a critical need to prevent treatment failure. A number of studies have emerged that highlight the catabolic process of autophagy in breast cancer as a mechanism of resistance to chemotherapy and targeted inhibitors. Furthermore, recent research has begun to dissect how autophagy signaling crosstalks with apoptotic signaling. Thus, a possible strategy in fighting resistance is to couple targeting of apoptotic and autophagy signaling pathways. In this review, we discuss how cellular response by autophagy circumvents cell death to promote resistance of breast cancers to HER2 inhibitors, as well as the potential avenues of therapeutic intervention.
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Affiliation(s)
- Joelle Zambrano
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, SC, USA
| | - Elizabeth S Yeh
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, SC, USA
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59
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Inoue K, Fry EA. Aberrant Splicing of Estrogen Receptor, HER2, and CD44 Genes in Breast Cancer. GENETICS & EPIGENETICS 2015; 7:19-32. [PMID: 26692764 PMCID: PMC4669075 DOI: 10.4137/geg.s35500] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 11/01/2015] [Accepted: 11/03/2015] [Indexed: 12/12/2022]
Abstract
Breast cancer (BC) is the most common cause of cancer-related death among women under the age of 50 years. Established biomarkers, such as hormone receptors (estrogen receptor [ER]/progesterone receptor) and human epidermal growth factor receptor 2 (HER2), play significant roles in the selection of patients for endocrine and trastuzumab therapies. However, the initial treatment response is often followed by tumor relapse with intrinsic resistance to the first-line therapy, so it has been expected to identify novel molecular markers to improve the survival and quality of life of patients. Alternative splicing of pre-messenger RNAs is a ubiquitous and flexible mechanism for the control of gene expression in mammalian cells. It provides cells with the opportunity to create protein isoforms with different, even opposing, functions from a single genomic locus. Aberrant alternative splicing is very common in cancer where emerging tumor cells take advantage of this flexibility to produce proteins that promote cell growth and survival. While a number of splicing alterations have been reported in human cancers, we focus on aberrant splicing of ER, HER2, and CD44 genes from the viewpoint of BC development. ERα36, a splice variant from the ER1 locus, governs nongenomic membrane signaling pathways triggered by estrogen and confers 4-hydroxytamoxifen resistance in BC therapy. The alternative spliced isoform of HER2 lacking exon 20 (Δ16HER2) has been reported in human BC; this isoform is associated with transforming ability than the wild-type HER2 and recapitulates the phenotypes of endocrine therapy-resistant BC. Although both CD44 splice isoforms (CD44s, CD44v) play essential roles in BC development, CD44v is more associated with those with favorable prognosis, such as luminal A subtype, while CD44s is linked to those with poor prognosis, such as HER2 or basal cell subtypes that are often metastatic. Hence, the detection of splice variants from these loci will provide keys to understand the pathogenesis, predict the prognosis, and choose specific therapies for BC.
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Affiliation(s)
- Kazushi Inoue
- Department of Pathology, Wake Forest University Health Sciences, Winston-Salem, NC, USA
| | - Elizabeth A. Fry
- Department of Pathology, Wake Forest University Health Sciences, Winston-Salem, NC, USA
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60
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Non-HER2 signaling pathways activated in resistance to anti-HER2 therapy in breast cancer. Breast Cancer Res Treat 2015; 153:493-505. [PMID: 26400847 DOI: 10.1007/s10549-015-3578-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 09/16/2015] [Indexed: 01/21/2023]
Abstract
HER2 receptor is overexpressed approximately in 20 % of human breast cancer (BC) and is a poor prognostic factor. Although therapies targeting this receptor have improved the prognosis of this cancer, up to 62 % patients treated with these drugs experiment progression during the first year of treatment. Some molecular mechanisms have been proposed to be responsible for this resistance, such as activation of alternative signaling pathways (through ERBB receptors and non-ERBB receptors or increased expression of ligands and alterations in HER2 signaling components). In this article, we will review the influence of genetic markers in non-HER2 signaling pathways investigated to date as cause of resistance to HER2-targeted drugs in HER2-positive BC patients. GRB7, included in the 17q12 amplicon, has been associated to poor prognosis in BC patients. Biomarkers like EPHAR and SRC, have demonstrated clinical relevance and prognostic value in HER2-positive BC patients. Non-invasive biomarkers, such as elevated IGF1 serum levels have been revealed as interesting biomarkers to be considered as predictors of trastuzumab clinical outcomes in BC patients. However, the prognostic value of most of the biomarkers investigated to date, such as HER3, IGF1R, PIK3CA, or AKT1 cannot be fully established yet, since results have not been conclusive.
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