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Subramanyan LV, Rasheed SAK, Wang L, Ghosh S, Ong MSN, Lakshmanan M, Wang M, Casey PJ. GNA13 suppresses proliferation of ER+ breast cancer cells via ERα dependent upregulation of the MYC oncogene. Breast Cancer Res 2024; 26:113. [PMID: 38965558 PMCID: PMC11225210 DOI: 10.1186/s13058-024-01866-x] [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: 03/05/2024] [Accepted: 06/26/2024] [Indexed: 07/06/2024] Open
Abstract
GNA13 (Gα13) is one of two alpha subunit members of the G12/13 family of heterotrimeric G-proteins which mediate signaling downstream of GPCRs. It is known to be essential for embryonic development and vasculogenesis and has been increasingly shown to be involved in mediating several steps of cancer progression. Recent studies found that Gα13 can function as an oncogene and contributes to progression and metastasis of multiple tumor types, including ovarian, head and neck and prostate cancers. In most cases, Gα12 and Gα13, as closely related α-subunits in the subfamily, have similar cellular roles. However, in recent years their differences in signaling and function have started to emerge. We previously identified that Gα13 drives invasion of Triple Negative Breast Cancer (TNBC) cells in vitro. As a highly heterogenous disease with various well-defined molecular subtypes (ER+ /Her2-, ER+ /Her2+, Her2+, TNBC) and subtype associated outcomes, the function(s) of Gα13 beyond TNBC should be explored. Here, we report the finding that low expression of GNA13 is predictive of poorer survival in breast cancer, which challenges the conventional idea of Gα12/13 being universal oncogenes in solid tumors. Consistently, we found that Gα13 suppresses the proliferation in multiple ER+ breast cancer cell lines (MCF-7, ZR-75-1 and T47D). Loss of GNA13 expression drives cell proliferation, soft-agar colony formation and in vivo tumor formation in an orthotopic xenograft model. To evaluate the mechanism of Gα13 action, we performed RNA-sequencing analysis on these cell lines and found that loss of GNA13 results in the upregulation of MYC signaling pathways in ER+ breast cancer cells. Simultaneous silencing of MYC reversed the proliferative effect from the loss of GNA13, validating the role of MYC in Gα13 regulation of proliferation. Further, we found Gα13 regulates the expression of MYC, at both the transcript and protein level in an ERα dependent manner. Taken together, our study provides the first evidence for a tumor suppressive role for Gα13 in breast cancer cells and demonstrates for the first time the direct involvement of Gα13 in ER-dependent regulation of MYC signaling. With a few exceptions, elevated Gα13 levels are generally considered to be oncogenic, similar to Gα12. This study demonstrates an unexpected tumor suppressive role for Gα13 in ER+ breast cancer via regulation of MYC, suggesting that Gα13 can have subtype-dependent tumor suppressive roles in breast cancer.
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Affiliation(s)
| | | | - Lijin Wang
- Centre for Computational Biology and Program in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore, Singapore
| | - Sujoy Ghosh
- Centre for Computational Biology and Program in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore, Singapore
- Bioinformatics and Computational Biology, Pennington Biomedical Research Center, Baton Rouge, LA, 70808, USA
| | - Michelle Shi Ning Ong
- Biopharma Innovations and Solutions, Institute of Molecular and Cell Biology, Singapore, Singapore
| | - Manikandan Lakshmanan
- Biopharma Innovations and Solutions, Institute of Molecular and Cell Biology, Singapore, Singapore
| | - Mei Wang
- Programme in Cancer and Stem Cell Biology, Duke-NUS Medical School, Singapore, Singapore.
- Department of Biochemistry, National University of Singapore, Singapore, Singapore.
| | - Patrick J Casey
- Programme in Cancer and Stem Cell Biology, Duke-NUS Medical School, Singapore, Singapore.
- Dept. of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC, USA.
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Tessmann JW, Deng P, Durham J, Li C, Banerjee M, Wang Q, Goettl RA, He D, Wang C, Lee EY, Evers BM, Hennig B, Zaytseva YY. Perfluorooctanesulfonic acid exposure leads to downregulation of 3-hydroxy-3-methylglutaryl-CoA synthase 2 expression and upregulation of markers associated with intestinal carcinogenesis in mouse intestinal tissues. CHEMOSPHERE 2024; 359:142332. [PMID: 38754493 PMCID: PMC11157449 DOI: 10.1016/j.chemosphere.2024.142332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Revised: 05/06/2024] [Accepted: 05/12/2024] [Indexed: 05/18/2024]
Abstract
Perfluorooctanesulfonic acid (PFOS) is a widely recognized environment pollutant known for its high bioaccumulation potential and a long elimination half-life. Several studies have shown that PFOS can alter multiple biological pathways and negatively affect human health. Considering the direct exposure to the gastrointestinal (GI) tract to environmental pollutants, PFOS can potentially disrupt intestinal homeostasis. However, there is limited knowledge about the effect of PFOS exposure on normal intestinal tissues, and its contribution to GI-associated diseases remains to be determined. In this study, we examined the effect of PFOS exposure on the gene expression profile of intestinal tissues of C57BL/6 mice using RNAseq analysis. We found that PFOS exposure in drinking water significantly downregulates mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase 2 (HMGCS2), a rate-limiting ketogenic enzyme, in intestinal tissues of mice. We found that diets containing the soluble fibers inulin and pectin, which are known to be protective against PFOS exposure, were ineffective in reversing the downregulation of HMGCS2 expression in vivo. Analysis of intestinal tissues also demonstrated that PFOS exposure leads to upregulation of proteins implicated in colorectal carcinogenesis, including β-catenin, c-MYC, mTOR and FASN. Consistent with the in vivo results, PFOS exposure leads to downregulation of HMGCS2 in mouse and human normal intestinal organoids in vitro. Furthermore, we show that shRNA-mediated knockdown of HMGCS2 in a human normal intestinal cell line resulted in increased cell proliferation and upregulation of key proliferation-associated proteins such as cyclin D, survivin, ERK1/2 and AKT, along with an increase in lipid accumulation. In summary, our results suggest that PFOS exposure may contribute to pathological changes in normal intestinal cells via downregulation of HMGCS2 expression and upregulation of pro-carcinogenic signaling pathways that may increase the risk of colorectal cancer development.
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Affiliation(s)
- Josiane Weber Tessmann
- Department of Toxicology and Cancer Biology, University of Kentucky, Lexington, KY 40536, USA.
| | - Pan Deng
- College of Pharmaceutical Sciences, Soochow University, Suzhou, China.
| | - Jerika Durham
- Department of Toxicology and Cancer Biology, University of Kentucky, Lexington, KY 40536, USA.
| | - Chang Li
- Markey Cancer Center, University of Kentucky, Lexington, KY 40536, USA.
| | - Moumita Banerjee
- Markey Cancer Center, University of Kentucky, Lexington, KY 40536, USA.
| | - Qingding Wang
- Markey Cancer Center, University of Kentucky, Lexington, KY 40536, USA.
| | - Ryan A Goettl
- Markey Cancer Center Biostatistics and Bioinformatics Shared Resource Facility, University of Kentucky, Lexington, KY 40536, USA.
| | - Daheng He
- Markey Cancer Center Biostatistics and Bioinformatics Shared Resource Facility, University of Kentucky, Lexington, KY 40536, USA.
| | - Chi Wang
- Markey Cancer Center Biostatistics and Bioinformatics Shared Resource Facility, University of Kentucky, Lexington, KY 40536, USA.
| | - Eun Y Lee
- Department of Pathology and Laboratory Medicine, University of Kentucky, Lexington, KY 40536, USA.
| | - B Mark Evers
- Markey Cancer Center, University of Kentucky, Lexington, KY 40536, USA.
| | - Bernhard Hennig
- Department of Animal and Food Sciences, University of Kentucky, Lexington, KY 40536, USA.
| | - Yekaterina Y Zaytseva
- Department of Toxicology and Cancer Biology, University of Kentucky, Lexington, KY 40536, USA; Markey Cancer Center, University of Kentucky, Lexington, KY 40536, USA.
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Thakur A, Rana N, Kumar R. Altered hormone expression induced genetic changes leads to breast cancer. Curr Opin Oncol 2024; 36:115-122. [PMID: 38441060 DOI: 10.1097/cco.0000000000001019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2024]
Abstract
PURPOSE OF REVIEW Breast cancer ranks first among gynecological cancer in India. It is associated with urbanization, changes in lifestyle and obesity. Hormones also play a crucial role in the development of breast cancer. Steroid hormones play critical role in development of breast cancer. RECENT FINDING Breast cancer is caused due to alteration in different hormone expressions leading to genetic instability. Loss or gains of functions due to genetic instability were associated with the alterations in housekeeping genes. Up-regulation in c-myc, signal transducer and activator of transcription (STAT), CREB-regulated transcription coactivator (CRTC), and eukaryotic translation initiation factor 4E (eIF4E) may cause the development of breast cancer. Peptide hormones are commonly following the phosphoinositide 3-kinases (PI3K) pathway for activation of cell cycle causing uncontrolled proliferation. Although steroid hormones are following the Ras/Raf/mitogen-activated protein kinase (MEK) pathway, their hyper-activation of these pathways causes extracellular-signal-regulated kinase (ERK) and MAPK activation, leading to carcinogenesis. SUMMARY Alteration in cell cycle proteins, oncogenes, tumor suppressor genes, transcription and translation factors lead to breast cancer. Apoptosis plays a vital role in the elimination of abnormal cells but failure in any of these apoptotic pathways may cause tumorigenesis. Hence, a complex interplay of hormonal and genetic factors is required to maintain homeostasis in breast cells. Imbalance in homeostasis of these hormone and genes may lead to breast cancer.
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Affiliation(s)
- Anchal Thakur
- Department of Animal sciences, Central University of Himachal Pradesh, Dharamshala, H.P
| | - Navya Rana
- Department of Animal sciences, Central University of Himachal Pradesh, Dharamshala, H.P
| | - Ranjit Kumar
- Department of Zoology, Nagaland University, Lumami, Nagaland
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Nicolini A, Ferrari P. Targeted Therapies and Drug Resistance in Advanced Breast Cancer, Alternative Strategies and the Way beyond. Cancers (Basel) 2024; 16:466. [PMID: 38275906 PMCID: PMC10814066 DOI: 10.3390/cancers16020466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 01/16/2024] [Accepted: 01/19/2024] [Indexed: 01/27/2024] Open
Abstract
"Targeted therapy" or "precision medicine" is a therapeutic strategy launched over two decades ago. It relies on drugs that inhibit key molecular mechanisms/pathways or genetic/epigenetic alterations that promote different cancer hallmarks. Many clinical trials, sponsored by multinational drug companies, have been carried out. During this time, research has increasingly uncovered the complexity of advanced breast cancer disease. Despite high expectations, patients have seen limited benefits from these clinical trials. Commonly, only a minority of trials are successful, and the few approved drugs are costly. The spread of this expensive therapeutic strategy has constrained the resources available for alternative research. Meanwhile, due to the high cost/benefit ratio, other therapeutic strategies have been proposed by researchers over time, though they are often not pursued due to a focus on precision medicine. Notable among these are drug repurposing and counteracting micrometastatic disease. The former provides an obvious answer to expensive targeted therapies, while the latter represents a new field to which efforts have recently been devoted, offering a "way beyond" the current research.
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Affiliation(s)
- Andrea Nicolini
- Department of Oncology, Transplantations and New Technologies in Medicine, University of Pisa, 56126 Pisa, Italy
| | - Paola Ferrari
- Unit of Oncology, Department of Medical and Oncological Area, Azienda Ospedaliera—Universitaria Pisana, 56125 Pisa, Italy;
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Jiang Y, Wang Y, Zhao L, Yang W, Pan L, Bai Y, Wang Y, Li Y. P129, a pyrazole ring-containing isolongifolanone-derivate: synthesis and investigation of anti-glioma action mechanism. Discov Oncol 2024; 15:6. [PMID: 38184514 PMCID: PMC10771574 DOI: 10.1007/s12672-024-00858-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Accepted: 01/03/2024] [Indexed: 01/08/2024] Open
Abstract
BACKGROUND Cyclin-dependent kinase-2 (CDK-2) is an important regulatory factor in the G1/S phase transition. CDK-2 targeting has been shown to suppress the viability of multiple cancers. However, the exploration and application of a CDK-2 inhibitor in the treatment of glioblastoma are sparse. METHODS We synthesized P129 based on isolongifolanone, a natural product with anti-tumor activity. Network pharmacology analysis was conducted to predict the structural stability, affinity, and pharmacological and toxicological properties of P129. Binding analysis and CETSA verified the ability of P129 to target CDK-2. The effect of P129 on the biological behavior of glioma cells was analyzed by the cell counting kit-8, colony formation, flow cytometry, and other experiments. Western blotting was used to detect the expression changes of proteins involved in the cell cycle, cell apoptosis, and epithelial-mesenchymal transition. RESULTS Bioinformatics analysis and CETSA showed that P129 exhibited good intestinal absorption and blood-brain barrier penetrability together with high stability and affinity with CDK-2, with no developmental toxicity. The viability, proliferation, and migration of human glioma cells were significantly inhibited by P129 in a dose- and time-dependent manner. Flow cytometry and western blotting analyses showed G0/G1 arrest and lower CDK-2 expression in cells treated with P129 than in the controls. The apoptotic ratio of glioma cells increased significantly with increasing concentrations of P129 combined with karyopyknosis and karyorrhexis. Apoptosis occurred via the mitochondrial pathway. CONCLUSION The pyrazole ring-containing isolongifolanone derivate P129 exhibited promising anti-glioma activity by targeting CDK-2 and promoting apoptosis, indicating its potential importance as a new chemotherapeutic option for glioma.
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Affiliation(s)
- Yining Jiang
- Department of Neurosurgery, First Hospital of Jilin University, No.71, Xinmin Street, Changchun, 130021, Jilin, People's Republic of China
| | - Yunyun Wang
- School of Pharmacy and Jiangsu Province Key Laboratory for Inflammation and Molecular Drug Target, Nantong University, Nantong, 226001, China
| | - Liyan Zhao
- Department of Blood Transfusion, Second Hospital of Jilin University, Changchun, 130041, China
| | - Wenzhuo Yang
- Department of Neurosurgery, Cancer Hospital of Sun Yat Sen University, Guangzhou, 510060, China
| | - Lin Pan
- Department of Neurosurgery, First Hospital of Jilin University, No.71, Xinmin Street, Changchun, 130021, Jilin, People's Republic of China
| | - Yang Bai
- Department of Neurosurgery, First Hospital of Jilin University, No.71, Xinmin Street, Changchun, 130021, Jilin, People's Republic of China
| | - Yubo Wang
- Department of Neurosurgery, First Hospital of Jilin University, No.71, Xinmin Street, Changchun, 130021, Jilin, People's Republic of China
| | - Yunqian Li
- Department of Neurosurgery, First Hospital of Jilin University, No.71, Xinmin Street, Changchun, 130021, Jilin, People's Republic of China.
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Höller A, Nguyen-Sträuli BD, Frauchiger-Heuer H, Ring A. "Diagnostic and Prognostic Biomarkers of Luminal Breast Cancer: Where are We Now?". BREAST CANCER (DOVE MEDICAL PRESS) 2023; 15:525-540. [PMID: 37533589 PMCID: PMC10392911 DOI: 10.2147/bctt.s340741] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Accepted: 07/12/2023] [Indexed: 08/04/2023]
Abstract
Luminal breast cancers are hormone receptor (estrogen and/or progesterone) positive that are further divided into HER2-negative luminal A and HER2-positive luminal B subtypes. According to currently accepted convention, they represent the most common subtypes of breast cancer, accounting for approximately 70% of cases. Biomarkers play a critical role in the functional characterization, prognostication, and therapeutic prediction, rendering them indispensable for the clinical management of invasive breast cancer. Traditional biomarkers include clinicopathological parameters, which are increasingly extended by genetic and other molecular markers, enabling the comprehensive characterization of patients with luminal breast cancer. Liquid biopsies capturing and analyzing circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA) are emerging technologies that envision personalized management through precision oncology. This article reviews key biomarkers in luminal breast cancer and ongoing developments.
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Affiliation(s)
- Anna Höller
- Department of Gynecology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Bich Doan Nguyen-Sträuli
- Department of Gynecology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
- Department of Biology, Institute of Molecular Health Sciences, Swiss Federal Institute of Technology (ETH) Zurich, Zurich, Switzerland
| | - Heike Frauchiger-Heuer
- Department of Gynecology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Alexander Ring
- Department of Gynecology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
- Department of Biology, Institute of Molecular Health Sciences, Swiss Federal Institute of Technology (ETH) Zurich, Zurich, Switzerland
- Department of Medical Oncology and Hematology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
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Ke M, Sun N, Lin Z, Zhang P, Hu Y, Wu S, Zheng Z, Lu Y, Jin H. SNHG18 inhibits bladder cancer cell proliferation by increasing p21 transcription through destabilizing c-Myc protein. Cancer Cell Int 2023; 23:48. [PMID: 36927398 PMCID: PMC10018893 DOI: 10.1186/s12935-023-02887-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 03/03/2023] [Indexed: 03/17/2023] Open
Abstract
BACKGROUND Long non-coding RNAs (lncRNAs) have been confirmed to play important roles in various cancers including bladder cancer (BC). The precise expression pattern of lncRNA small nucleolar RNA host gene 18 (SNHG18) in BC and its mechanisms of action have not been fully explored. MATERIALS AND METHODS The expression of SNHG18 was evaluated by RT-qPCR in bladder cancer clinical samples and human bladder cancer cell lines, and stable cell lines overexpressing SNHG18 were constructed. The effect of SNHG18 on the proliferation of bladder cancer cells was detected by soft agar colony formation test, ATP activity test and subcutaneous tumorigenesis model in nude mice. The specific mechanism of SNHG18 inhibition of bladder cancer proliferation was studied by flow cytometry, western blotting, dual luciferase reporter gene assay and protein degradation assay. RESULTS We found that SNHG18 is significantly downregulated in BC tissues and cell lines. Kaplan-Meier analysis showed that SNHG18 expression is positively correlated with survival in BC patients. Ectopic overexpression of SNHG18 significantly inhibited the proliferation of BC cells in vitro and in vivo. Further mechanistic investigations demonstrated that SNHG18 inhibited c-Myc expression by modulating the ubiquitination-proteasome pathway and that c-Myc is the critical transcription factor that mediates SNHG18 inhibition of BC growth by directly binding to the p21 promoter, which was attributed with significant p21 accumulation. CONCLUSIONS SNHG18 promotes the transcription and expression of p21 by inhibiting c-Myc expression, leading to G0-G1 arrest and inhibiting the proliferation of bladder cancer cells. These findings highlight a novel cell cycle regulatory mechanism involving the SNHG18/c-Myc/p21 pathway in BC pathogenesis and could potentially lead to new lncRNA-based diagnostics and/or therapeutics for BC.
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Affiliation(s)
- Meixia Ke
- Zhejiang Provincial Key Laboratory of Medical Genetics, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China.,Clinical Laboratory, Dongyang People's Hospital, Dongyang, 322100, Zhejiang, China
| | - Ning Sun
- Zhejiang Provincial Key Laboratory of Medical Genetics, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China
| | - Zhenni Lin
- Zhejiang Provincial Key Laboratory of Medical Genetics, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China
| | - Peipei Zhang
- Zhejiang Provincial Key Laboratory of Medical Genetics, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China
| | - Yan Hu
- Zhejiang Provincial Key Laboratory of Medical Genetics, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China
| | - Shuilian Wu
- Zhejiang Provincial Key Laboratory of Medical Genetics, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China
| | - Zhijian Zheng
- Zhejiang Provincial Key Laboratory of Medical Genetics, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China
| | - Yongyong Lu
- Department of Urology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China.
| | - Honglei Jin
- Zhejiang Provincial Key Laboratory of Medical Genetics, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China.
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Safeguarding DNA Replication: A Golden Touch of MiDAS and Other Mechanisms. Int J Mol Sci 2022; 23:ijms231911331. [PMID: 36232633 PMCID: PMC9570362 DOI: 10.3390/ijms231911331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 09/19/2022] [Accepted: 09/20/2022] [Indexed: 11/21/2022] Open
Abstract
DNA replication is a tightly regulated fundamental process allowing the correct duplication and transfer of the genetic information from the parental cell to the progeny. It involves the coordinated assembly of several proteins and protein complexes resulting in replication fork licensing, firing and progression. However, the DNA replication pathway is strewn with hurdles that affect replication fork progression during S phase. As a result, cells have adapted several mechanisms ensuring replication completion before entry into mitosis and segregating chromosomes with minimal, if any, abnormalities. In this review, we describe the possible obstacles that a replication fork might encounter and how the cell manages to protect DNA replication from S to the next G1.
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Estrogen Induces c-myc Transcription by Binding to Upstream ERE Element in Promoter. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12146853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Estrogen Receptor α(ERα) is reported to regulate the expression of many target genes by binding to specific estrogen response elements (EREs) in their promoters. c-myc is known to be over-expressed in most of the human carcinomas due to dysregulated transcription, translation, or protein stability. Estrogen (E) can induce the c-myc expression by binding to an upstream enhancer element in its promoter. This suggests that elevated estradiol (E2), a potent form of estrogen, levels could induce the expression of c-myc in breast cancer (BC). The expression of c-myc and estradiol were induced at Stage III and Stage IV of breast cancer. c-myc and estradiol expression was also associated with the established risk factors of breast cancer, such as BMI. Age at the time of the disease was alsocorrelated with the relative expression of c-myc and estradiol (p < 0.0007 and p < 0.000001). The correlation coefficient (R = 0.462) shows a positive relationship between estradiol bound ER, ER, and c-myc. Docking energy −229 kJ/mol suggests the binding affinity of estradiol bound ER binding to 500 bp upstream of proximal promotor of c-myc at three distinct positions. The data presented in this study proposed that the expression of c-myc and estradiol are directly correlated in breast cancer. The prognostic utility of an induced level of c-myc associated with the normal status of the c-myc gene and estradiol for patients with metastatic carcinoma should be explored further.
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Moore KM, Cerqueira V, MacLeod KG, Mullen P, Hayward RL, Green S, Harrison DJ, Cameron DA, Langdon SP. Collateral-resistance to estrogen and HER-activated growth is associated with modified AKT, ERα, and cell-cycle signaling in a breast cancer model. EXPLORATION OF TARGETED ANTI-TUMOR THERAPY 2022; 3:97-116. [PMID: 35441158 PMCID: PMC7612628 DOI: 10.37349/etat.2022.00074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Aim: A model of progressively endocrine-resistant breast cancer was investigated to identify changes that can occur in signaling pathways after endocrine manipulation. Methods: The MCF7 breast cancer model is sensitive to estrogens and anti-estrogens while variant lines previously derived from wild-type MCF7 are either relatively 17β-estradiol (E2
)-insensitive (LCC1) or fully resistant to estrogen and anti-estrogens (LCC9). Results: In LCC1 and LCC9 cell lines, loss of estrogen sensitivity was accompanied by loss of growth response to transforming growth factor alpha (TGFα), heregulin-beta and pertuzumab. LCC1 and LCC9 cells had enhanced AKT phosphorylation relative to MCF7 which was reflected in downstream activation of phospho-mechanistic target of rapamycin (mTOR), phospho-S6, and phospho-estrogen receptor alpha Ser167 [ERα(Ser167)]. Both AKT2 and AKT3 were phosphorylated in the resistant cell lines, but small interfering RNA (siRNA) knockdown suggested that all three AKT isoforms contributed to growth response. ERα(Ser118) phosphorylation was increased by E2 and TGFα in MCF7, by E2 only in LCC1, but by neither in LCC9 cells. Multiple alterations in E2-mediated cell cycle control were identified in the endocrine-resistant cell lines including increased expression of MYC, cyclin A1, cyclin D1, cyclin-dependent kinase 1 (CDK1), CDK2, and hyperphosphorylated retinoblastoma protein (ppRb), whereas p21 and p27 were reduced. Estrogen modulated expression of these regulators in MCF7 and LCC1 cells but not in LCC9 cells. Seliciclib inhibited CDK2 activation in MCF7 cells but not in resistant variants; in all lines, it reduced ppRb, increased p53 associated responses including p21, p53 up-regulated modulator of apoptosis (PUMA), and p53 apoptosis-inducing protein 1 (p53AIP1), inhibited growth, and produced G2/M block and apoptosis. Conclusions: Multiple changes occur with progression of endocrine resistance in this model with AKT activation contributing to E2 insensitivity and loss of ERα(Ser118) phosphorylation being associated with full resistance. Cell cycle regulation is modified in endocrine-resistant breast cancer cells, and seliciclib is effective in both endocrine-sensitive and resistant diseases.
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Affiliation(s)
- Kate M. Moore
- 1Cancer Research UK Edinburgh Centre, Institute of Genetics and Cancer, University of Edinburgh, Crewe Road South, EH4 2XR Edinburgh, UK 2Cancer Research UK Barts Centre, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, Charterhouse Square, EC1M 6BQ London, UK
| | - Vera Cerqueira
- 1Cancer Research UK Edinburgh Centre, Institute of Genetics and Cancer, University of Edinburgh, Crewe Road South, EH4 2XR Edinburgh, UK 3West of Scotland Clinical Genetics Service, Queen Elizabeth University Hospital, G51 4TF Glasgow, UK
| | - Kenneth G. MacLeod
- 1Cancer Research UK Edinburgh Centre, Institute of Genetics and Cancer, University of Edinburgh, Crewe Road South, EH4 2XR Edinburgh, UK
| | - Peter Mullen
- 4School of Medicine, University of St Andrews, North Haugh, KY16 9TF St Andrews, UK
| | - Richard L. Hayward
- 1Cancer Research UK Edinburgh Centre, Institute of Genetics and Cancer, University of Edinburgh, Crewe Road South, EH4 2XR Edinburgh, UK
| | - Simon Green
- 5Cyclacel Ltd, James Lindsay Place, Dundee Technopole, DD1 5JJ Dundee, UK
| | - David J. Harrison
- 4School of Medicine, University of St Andrews, North Haugh, KY16 9TF St Andrews, UK
| | - David A. Cameron
- 1Cancer Research UK Edinburgh Centre, Institute of Genetics and Cancer, University of Edinburgh, Crewe Road South, EH4 2XR Edinburgh, UK
| | - Simon P. Langdon
- 1Cancer Research UK Edinburgh Centre, Institute of Genetics and Cancer, University of Edinburgh, Crewe Road South, EH4 2XR Edinburgh, UK
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Saatci O, Huynh-Dam KT, Sahin O. Endocrine resistance in breast cancer: from molecular mechanisms to therapeutic strategies. J Mol Med (Berl) 2021; 99:1691-1710. [PMID: 34623477 PMCID: PMC8611518 DOI: 10.1007/s00109-021-02136-5] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 08/20/2021] [Accepted: 09/06/2021] [Indexed: 12/31/2022]
Abstract
Estrogen receptor-positive (ER +) breast cancer accounts for approximately 75% of all breast cancers. Endocrine therapies, including selective ER modulators (SERMs), aromatase inhibitors (AIs), and selective ER down-regulators (SERDs) provide substantial clinical benefit by reducing the risk of disease recurrence and mortality. However, resistance to endocrine therapies represents a major challenge, limiting the success of ER + breast cancer treatment. Mechanisms of endocrine resistance involve alterations in ER signaling via modulation of ER (e.g., ER downregulation, ESR1 mutations or fusions); alterations in ER coactivators/corepressors, transcription factors (TFs), nuclear receptors and epigenetic modulators; regulation of signaling pathways; modulation of cell cycle regulators; stress signaling; and alterations in tumor microenvironment, nutrient stress, and metabolic regulation. Current therapeutic strategies to improve outcome of endocrine-resistant patients in clinics include inhibitors against mechanistic target of rapamycin (mTOR), cyclin-dependent kinase (CDK) 4/6, and the phosphoinositide 3-kinase (PI3K) subunit, p110α. Preclinical studies reveal novel therapeutic targets, some of which are currently tested in clinical trials as single agents or in combination with endocrine therapies, such as ER partial agonists, ER proteolysis targeting chimeras (PROTACs), next-generation SERDs, AKT inhibitors, epidermal growth factor receptor 1 and 2 (EGFR/HER2) dual inhibitors, HER2 targeting antibody-drug conjugates (ADCs) and histone deacetylase (HDAC) inhibitors. In this review, we summarize the established and emerging mechanisms of endocrine resistance, alterations during metastatic recurrence, and discuss the approved therapies and ongoing clinical trials testing the combination of novel targeted therapies with endocrine therapy in endocrine-resistant ER + breast cancer patients.
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Affiliation(s)
- Ozge Saatci
- Department of Drug Discovery and Biomedical Sciences, University of South Carolina, 715, Sumter Street, CLS609D, Columbia, SC, 29208, USA
| | - Kim-Tuyen Huynh-Dam
- Department of Drug Discovery and Biomedical Sciences, University of South Carolina, 715, Sumter Street, CLS609D, Columbia, SC, 29208, USA
| | - Ozgur Sahin
- Department of Drug Discovery and Biomedical Sciences, University of South Carolina, 715, Sumter Street, CLS609D, Columbia, SC, 29208, USA.
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12
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Co-Targeting PIM Kinase and PI3K/mTOR in NSCLC. Cancers (Basel) 2021; 13:cancers13092139. [PMID: 33946744 PMCID: PMC8125027 DOI: 10.3390/cancers13092139] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 03/25/2021] [Accepted: 04/20/2021] [Indexed: 11/16/2022] Open
Abstract
Simple Summary PIM kinases interact with major oncogenic players, including the PI3K/Akt pathway, and provide an escape mechanism leading to drug resistance. This study examined PIM kinase expression in NSCLC and the potential of PIM1 as a prognostic marker. The effect on cell signaling of novel preclinical PI3K/mTOR/PIM kinase inhibitor IBL-301 was compared to PI3K/mTOR inhibition in vitro and ex vivo. PI3K-mTOR inhibitor sensitive (H1975P) and resistant (H1975GR) cells were compared for altered IL6/STAT3 pathway expression and sensitivity to IBL-301. All three PIM kinases are expressed in NSCLC and PIM1 is a marker of poor prognosis. IBL-301 inhibited c-Myc, the PI3K-Akt and JAK/STAT pathways in vitro and in NSCLC tumor tissue explants. IBL-301 also inhibited secreted pro-inflammatory cytokine MCP-1. PIM kinases were activated in H1975GR cells which were more sensitive to IBL-301 than H1975P cells. A miRNA signature of PI3K-mTOR resistance was validated. Co-targeting PIM kinase and PI3K-mTOR warrants further clinical investigation. Abstract PIM kinases are constitutively active proto-oncogenic serine/threonine kinases that play a role in cell cycle progression, metabolism, inflammation and drug resistance. PIM kinases interact with and stabilize p53, c-Myc and parallel signaling pathway PI3K/Akt. This study evaluated PIM kinase expression in NSCLC and in response to PI3K/mTOR inhibition. It investigated a novel preclinical PI3K/mTOR/PIM inhibitor (IBL-301) in vitro and in patient-derived NSCLC tumor tissues. Western blot analysis confirmed PIM1, PIM2 and PIM3 are expressed in NSCLC cell lines and PIM1 is a marker of poor prognosis in patients with NSCLC. IBL-301 decreased PIM1, c-Myc, pBAD and p4EBP1 (Thr37/46) and peIF4B (S406) protein levels in-vitro and MAP kinase, PI3K-Akt and JAK/STAT pathways in tumor tissue explants. IBL-301 significantly decreased secreted pro-inflammatory cytokine MCP-1. Altered mRNA expression, including activated PIM kinase and c-Myc, was identified in Apitolisib resistant cells (H1975GR) by an IL-6/STAT3 pathway array and validated by Western blot. H1975GR cells were more sensitive to IBL-301 than parent cells. A miRNA array identified a dysregulated miRNA signature of PI3K/mTOR drug resistance consisting of regulators of PIM kinase and c-Myc (miR17-5p, miR19b-3p, miR20a-5p, miR15b-5p, miR203a, miR-206). Our data provides a rationale for co-targeting PIM kinase and PI3K-mTOR to improve therapeutic response in NSCLC.
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13
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Zabihi M, Safaroghli-Azar A, Gharehbaghian A, Allahbakhshian Farsani M, Bashash D. CDK Blockade Using AT7519 Suppresses Acute Myeloid Leukemia Cell Survival through the Inhibition of Autophagy and Intensifies the Anti-leukemic Effect of Arsenic Trioxide. IRANIAN JOURNAL OF PHARMACEUTICAL RESEARCH : IJPR 2020; 18:119-131. [PMID: 32802093 PMCID: PMC7393062 DOI: 10.22037/ijpr.2019.112560.13827] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The strong storyline behind the critical role of cyclin-dependent kinase (CDK) inhibitor proteins in natural defense against malignant transformation not only represents a heroic perspective for these proteins, but also provides a bright future for the application of small molecule inhibitors of CDKs in the novel cancer treatment strategies. The results of the present study revealed that the inhibition of CDKs using pan-CDK inhibitor AT7519, as revealed by the induction of G1 cell cycle arrest as well as the reduction of cyclins expression, resulted in decreased survival in acute myeloid leukemia (AML)-derived KG-1 cells, either in the context of single agent or in combination with arsenic trioxide (ATO). Apart from alterations in the expression of proliferation and apoptotic genes, the anti-survival property of AT7519 was coupled with the inhibition of autophagy-related genes. Notably, we found that the blockage of autophagy system in KG-1 cells resulted in a superior cytotoxic effect, introducing autophagy as a probable suppressor of cell death. As far as we are aware, to date, no study has reported the contributory mechanisms correlated with the less sensitivity of acute leukemia cells to AT7519 and our study suggested for the first time that the activation of both PI3K and c-Myc signaling pathways could overshadow, at least partly, the efficacy of this agent in KG-1 cells. Overall, due to the pharmacologic safety of AT7519, our study proposed this inhibitor as a promising agent for the treatment of AML either as a single agent or in a combined-modal strategy.
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Affiliation(s)
- Mitra Zabihi
- Department of Hematology and Blood Banking, School of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Ava Safaroghli-Azar
- Student Research Committee, Department of Hematology and Blood Banking, School of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Ahmad Gharehbaghian
- Department of Hematology and Blood Banking, School of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mehdi Allahbakhshian Farsani
- Department of Hematology and Blood Banking, School of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Davood Bashash
- Department of Hematology and Blood Banking, School of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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14
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Abdoli Shadbad M, Hajiasgharzadeh K, Baradaran B. Cross-talk between myeloid-derived suppressor cells and Mucin1 in breast cancer vaccination: On the verge of a breakthrough. Life Sci 2020; 258:118128. [PMID: 32710947 DOI: 10.1016/j.lfs.2020.118128] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 07/16/2020] [Accepted: 07/17/2020] [Indexed: 01/22/2023]
Abstract
Although breast cancer is one of the leading troublesome cancers, the available therapeutic options have not fulfilled the desired outcomes. Immune-based therapy has gained special attention for breast cancer treatment. Although this approach is highly tolerable, its low response rate has rendered it as an undesirable approach. This review aims to describe the essential oncogenic pathways involved in breast cancer, elucidate the immunosuppression and oncogenic effect of Mucin1, and introduce myeloid-derived suppressor cells, which are the main culprits of anti-tumoral immune response attenuation. The various auto-inductive loops between Mucin1 and myeloid-derived suppressor cells are focal in the suppression of anti-tumoral immune responses in patients with breast cancer. These cross-talks between the Mucin1 and myeloid-derived suppressor cells can be the underlying causes of immunotherapy's impotence for patients with breast cancer. This approach can pave the road for the development of a potent vaccine for patients with breast cancer and is translated into clinical settings.
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Affiliation(s)
| | - Khalil Hajiasgharzadeh
- Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; Connective Tissue Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Behzad Baradaran
- Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; Pharmaceutical Analysis Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; Neurosciences Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
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15
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Zhu X, Feng J, Fu W, Shu X, Wan X, Liu J. Effects of cisplatin on the proliferation, invasion and apoptosis of breast cancer cells following β‑catenin silencing. Int J Mol Med 2020; 45:1838-1850. [PMID: 32186756 PMCID: PMC7169654 DOI: 10.3892/ijmm.2020.4543] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 02/19/2020] [Indexed: 12/11/2022] Open
Abstract
Resistance to the chemotherapeutic drug cisplatin has been documented in various types of cancer, while the increased expression of β‑catenin has been observed in cisplatin‑resistant ovarian cancer. However, the involvement of β‑catenin in cisplatin resistance is unclear. The present study investigated the antitumor effect of cisplatin on the proliferation, invasion and apoptosis of breast cancer (BC) cells following β‑catenin silencing in BC, which is the most frequent type of malignancy among women. The expression of β‑catenin in BC tissues and cell lines was measured by reverse transcription‑quantitative polymerase chain reaction, and the association between expression levels and clinical characteristics was statistically analyzed. The viability of BC cell lines treated with siR‑β‑catenin or with siR‑β‑catenin and cisplatin in combination was determined using a Cell Counting Kit‑8 assay. The migratory and invasive abilities of BC cells treated with both siR‑β‑catenin and cisplatin were examined with Transwell assays. The CD44 antigen/intercellular adhesion molecule 1 expression ratio, cell cycle distribution and apoptosis levels of BC cells treated with siR‑β‑catenin and cisplatin in combination were detected by flow cytometry. The expression levels of apoptosis‑associated proteins, including caspase‑3/9, in the BC cells treated with both siR‑β‑catenin and cisplatin were investigated by western blot analysis. The levels of apoptosis in the BC cells following combined treatment with siR‑β‑catenin and cisplatin was further quantified by Hoechst 33342 staining. β‑catenin was identified to be highly expressed in BC tissues and cell lines and was associated with pathological stage and lymph node status. Following knockdown of β‑catenin expression, cisplatin treatment suppressed the viabilities, and the migratory and invasive capabilities of the T47D and MCF‑7 cells, and induced extensive apoptosis. β‑catenin knockdown upregulated caspase‑3/9 levels following cisplatin treatment and induced the apoptosis of T47D and MCF‑7 cells. In conclusion, β‑catenin may be of value as a therapeutic target during cisplatin treatment in patients with BC treated with cisplatin.
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Affiliation(s)
| | - Jia Feng
- Department of Laboratory Medicine
| | - Wenguang Fu
- Department of Hepatobiliary Surgery, The Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan 646000, P.R. China
| | | | - Xue Wan
- Department of Laboratory Medicine
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16
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Liang ZR, Qu LH, Ma LM. Differential impacts of charcoal-stripped fetal bovine serum on c-Myc among distinct subtypes of breast cancer cell lines. Biochem Biophys Res Commun 2020; 526:267-272. [PMID: 32209261 DOI: 10.1016/j.bbrc.2020.03.049] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Revised: 03/03/2020] [Accepted: 03/08/2020] [Indexed: 12/23/2022]
Abstract
Charcoal-stripped fetal bovine serum (CS-FBS) is frequently used in studies on hormone-responsive cancers to provide hormone-free cell culture conditions. CS-FBS may influence the growth of cancer cells; however, the underlying mechanisms remain unclear. In this study, we aimed to clarify the effects of CS-FBS on distinct subtypes of breast cancer cells. We found that the crucial oncoprotein c-Myc was significantly inhibited in estrogen receptor alpha (ER-α)-positive breast cancer cells when cultured in CS-FBS-supplemented medium, but it was not suppressed in ER-α-negative cells. The addition of 17β-estradiol (E2) to CS-FBS-supplemented medium rescued the CS-FBS-induced inhibition of c-Myc, while treatment with 5α-dihydrotestosterone (DHT) suppressed c-Myc expression. Our data demonstrated that CS-FBS may impede the growth of ER-α-positive breast cancer cells via c-Myc inhibition, and this was possibly due to the removal of estrogen. These results highlighted that the core drivers of c-Myc expression were subtype-specific depending on the distinct cell context and special caution should be exercised when using CS-FBS in studies of hormone-responsive cancer cells.
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Affiliation(s)
- Zi-Rui Liang
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, PR China.
| | - Liang-Hu Qu
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, PR China.
| | - Li-Ming Ma
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, PR China.
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17
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Loss of CDKN1A mRNA and Protein Expression Are Independent Predictors of Poor Outcome in Chromophobe Renal Cell Carcinoma Patients. Cancers (Basel) 2020; 12:cancers12020465. [PMID: 32079343 PMCID: PMC7072616 DOI: 10.3390/cancers12020465] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2019] [Revised: 01/24/2020] [Accepted: 02/13/2020] [Indexed: 01/10/2023] Open
Abstract
Chromophobe renal cell carcinoma (chRCC) patients have good prognosis. Only 5%-10% patients die of metastatic disease after tumorectomy, but tumor progression cannot be predicted by histopathological parameters alone. chRCC are characterized by losses of many chromosomes, whereas gene mutations are rare. In this study, we aim at identifying genes indicating chRCC progression. A bioinformatic approach was used to correlate chromosomal loss and mRNA expression from 15287 genes from The Cancer Genome Atlas (TCGA) database. All genes in TCGA chromophobe renal cancer dataset (KICH) for which a significant correlation between chromosomal loss and mRNA expression was shown, were identified and their associations with outcome was assessed. Genome-wide DNA copy-number alterations were analyzed by Affymetrix OncoScan® CNV FFPE Microarrays in a second cohort of Swiss chRCC. In both cohorts, tumors with loss of chromosomes 2, 6, 10, 13, 17 and 21 had signs of tumor progression. There were 4654 genes located on these chromosomes, and 13 of these genes had reduced mRNA levels, which was associated with poor outcome in chRCC. Decreased CDKN1A expression at mRNA (p = 0.02) and protein levels (p = 0.02) were associated with short overall survival and were independent predictors of prognosis (p <0.01 and <0.05 respectively). CDKN1A expression status is a prognostic biomarker independent of tumor stage. CDKN1A immunohistochemistry may be used to identify chRCC patients at greater risk of disease progression.
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18
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Tadesse S, Anshabo AT, Portman N, Lim E, Tilley W, Caldon CE, Wang S. Targeting CDK2 in cancer: challenges and opportunities for therapy. Drug Discov Today 2019; 25:406-413. [PMID: 31839441 DOI: 10.1016/j.drudis.2019.12.001] [Citation(s) in RCA: 146] [Impact Index Per Article: 29.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 11/01/2019] [Accepted: 12/02/2019] [Indexed: 12/13/2022]
Abstract
Cyclin-dependent kinase 2 (CDK2) plays a pivotal part in cell cycle regulation and is involved in a range of biological processes. CDK2 interacts with and phosphorylates proteins in pathways such as DNA damage, intracellular transport, protein degradation, signal transduction, DNA and RNA metabolism and translation. CDK2 and its regulatory subunits are deregulated in many human cancers and there is emerging evidence suggesting CDK2 inhibition elicits antitumor activity in a subset of tumors with defined genetic features. Previous CDK2 inhibitors were nonspecific and limited by off-target effects. The development of new-generation CDK2 inhibitors represents a therapeutic opportunity for CDK2-dependent cancers.
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Affiliation(s)
- Solomon Tadesse
- Centre for Drug Discovery and Development, University of South Australia Cancer Research Institute, Adelaide, SA 5000, Australia; Departement of Pharmaceutical Chemistry and Pharmacognosy, School of Pharmacy, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Abel T Anshabo
- Centre for Drug Discovery and Development, University of South Australia Cancer Research Institute, Adelaide, SA 5000, Australia
| | - Neil Portman
- Garvan Institute of Medical Research, The Kinghorn Cancer Centre, Darlinghurst, NSW 2010, Australia; St Vincent's Clinical School, UNSW Sydney, Darlinghurst, NSW 2010, Australia
| | - Elgene Lim
- Garvan Institute of Medical Research, The Kinghorn Cancer Centre, Darlinghurst, NSW 2010, Australia; St Vincent's Clinical School, UNSW Sydney, Darlinghurst, NSW 2010, Australia
| | - Wayne Tilley
- Adelaide Medical School, The University of Adelaide, SA 5001, Australia
| | - C Elizabeth Caldon
- Garvan Institute of Medical Research, The Kinghorn Cancer Centre, Darlinghurst, NSW 2010, Australia; St Vincent's Clinical School, UNSW Sydney, Darlinghurst, NSW 2010, Australia.
| | - Shudong Wang
- Centre for Drug Discovery and Development, University of South Australia Cancer Research Institute, Adelaide, SA 5000, Australia.
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Al Bitar S, Gali-Muhtasib H. The Role of the Cyclin Dependent Kinase Inhibitor p21 cip1/waf1 in Targeting Cancer: Molecular Mechanisms and Novel Therapeutics. Cancers (Basel) 2019; 11:cancers11101475. [PMID: 31575057 PMCID: PMC6826572 DOI: 10.3390/cancers11101475] [Citation(s) in RCA: 103] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 07/26/2019] [Accepted: 07/30/2019] [Indexed: 12/15/2022] Open
Abstract
p21cip1/waf1 mediates various biological activities by sensing and responding to multiple stimuli, via p53-dependent and independent pathways. p21 is known to act as a tumor suppressor mainly by inhibiting cell cycle progression and allowing DNA repair. Significant advances have been made in elucidating the potential role of p21 in promoting tumorigenesis. Here, we discuss the involvement of p21 in multiple signaling pathways, its dual role in cancer, and the importance of understanding its paradoxical functions for effectively designing therapeutic strategies that could selectively inhibit its oncogenic activities, override resistance to therapy and yet preserve its tumor suppressive functions.
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Affiliation(s)
- Samar Al Bitar
- Department of Biology, and Center for Drug Discovery, American University of Beirut, Beirut 1103, Lebanon.
| | - Hala Gali-Muhtasib
- Department of Biology, and Center for Drug Discovery, American University of Beirut, Beirut 1103, Lebanon.
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20
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Manu KA, Cao PHA, Chai TF, Casey PJ, Wang M. p21cip1/waf1 Coordinate Autophagy, Proliferation and Apoptosis in Response to Metabolic Stress. Cancers (Basel) 2019; 11:cancers11081112. [PMID: 31382612 PMCID: PMC6721591 DOI: 10.3390/cancers11081112] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 07/25/2019] [Accepted: 07/30/2019] [Indexed: 12/12/2022] Open
Abstract
Cancer cells possess metabolic properties that are different from benign cells. These unique characteristics have become attractive targets that are being actively investigated for cancer therapy. p21cip1/waf1, also known as Cyclin-Dependent Kinase inhibitor 1A, is encoded by the CDKN1A gene. It is a major p53 target gene involved in cell cycle progression that has been extensively evaluated. To date, p21 has been reported to regulate various cell functions, both dependent and independent of p53. Besides regulating the cell cycle, p21 also modulates apoptosis, induces senescence, and maintains cellular quiescence in response to various stimuli. p21 transcription is induced in response to stresses, including those from oxidative and chemotherapeutic treatment. A recent study has shown that in response to metabolic stresses such as nutrient and energy depletion, p21 expression is induced to regulate various cell functions. Despite the biological significance, the mechanism of p21 regulation in cancer adaptation to metabolic stress is underexplored and thus represents an exciting field. This review focuses on the recent development of p21 regulation in response to metabolic stress and its impact in inducing cell cycle arrest and death in cancer cells.
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Affiliation(s)
- Kanjoormana Aryan Manu
- Program in Cancer and Stem Cell Biology, Duke-NUS Graduate Medical School, Singapore 169857, Singapore
| | - Pham Hong Anh Cao
- Program in Cancer and Stem Cell Biology, Duke-NUS Graduate Medical School, Singapore 169857, Singapore
| | - Tin Fan Chai
- Program in Cancer and Stem Cell Biology, Duke-NUS Graduate Medical School, Singapore 169857, Singapore
| | - Patrick J Casey
- Program in Cancer and Stem Cell Biology, Duke-NUS Graduate Medical School, Singapore 169857, Singapore
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Mei Wang
- Program in Cancer and Stem Cell Biology, Duke-NUS Graduate Medical School, Singapore 169857, Singapore.
- Department of Biochemistry, National University of Singapore, Singapore 117596, Singapore.
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21
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Tokgun PE, Tokgun O, Kurt S, Tomatir AG, Akca H. MYC-driven regulation of long non-coding RNA profiles in breast cancer cells. Gene 2019; 714:143955. [PMID: 31326549 DOI: 10.1016/j.gene.2019.143955] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 06/27/2019] [Accepted: 06/28/2019] [Indexed: 11/25/2022]
Abstract
AIM MYC deregulation contributes to breast cancer development and progression. Deregulated expression levels of long non-coding RNAs (lncRNA) have been demonstrated to be critical players in development and/or maintenance of breast cancer. In this study we aimed to evaluate lncRNA expressions depending on MYC overexpression and knockdown in breast cancer cells. MATERIALS AND METHODS Cells were infected with lentiviral vectors by either knockdown or overexpression of c-MYC. LncRNA cDNA was transcribed from total RNA samples and lncRNAs were evaluated by qRT-PCR. RESULTS Our results indicated that some of the lncRNAs having tumor suppressor (GAS5, MEG3, lincRNA-p21) and oncogenic roles (HOTAIR) are regulated by c-MYC. CONCLUSION We observed that c-MYC regulates lncRNAs that have important roles on proliferation, cell cycle and etc. Further studies will give us a light to identify molecular mechanisms related to MYC-lncRNA regulatory pathways in breast cancer.
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Affiliation(s)
- Pervin Elvan Tokgun
- Department of Medical Genetics, Faculty of Medicine, Pamukkale University, Denizli, Turkey.
| | - Onur Tokgun
- Department of Medical Genetics, Faculty of Medicine, Pamukkale University, Denizli, Turkey.
| | - Serap Kurt
- Department of Medical Biology, Faculty of Medicine, Pamukkale University, Denizli, Turkey.
| | - Ayse Gaye Tomatir
- Department of Medical Biology, Faculty of Medicine, Pamukkale University, Denizli, Turkey.
| | - Hakan Akca
- Department of Medical Genetics, Faculty of Medicine, Pamukkale University, Denizli, Turkey.
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22
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Berberine enhances posttranslational protein stability of p21/cip1 in breast cancer cells via down-regulation of Akt. Mol Cell Biochem 2019; 458:49-59. [DOI: 10.1007/s11010-019-03529-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 03/16/2019] [Indexed: 12/26/2022]
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23
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Moussa RS, Park KC, Kovacevic Z, Richardson DR. Ironing out the role of the cyclin-dependent kinase inhibitor, p21 in cancer: Novel iron chelating agents to target p21 expression and activity. Free Radic Biol Med 2019; 133:276-294. [PMID: 29572098 DOI: 10.1016/j.freeradbiomed.2018.03.027] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 03/02/2018] [Accepted: 03/14/2018] [Indexed: 12/12/2022]
Abstract
Iron (Fe) has become an important target for the development of anti-cancer therapeutics with a number of Fe chelators entering human clinical trials for advanced and resistant cancer. An important aspect of the activity of these compounds is their multiple molecular targets, including those that play roles in arresting the cell cycle, such as the cyclin-dependent kinase inhibitor, p21. At present, the exact mechanism by which Fe chelators regulate p21 expression remains unclear. However, recent studies indicate the ability of chelators to up-regulate p21 at the mRNA level was dependent on the chelator and cell-type investigated. Analysis of the p21 promoter identified that the Sp1-3-binding site played a significant role in the activation of p21 transcription by Fe chelators. Furthermore, there was increased Sp1/ER-α and Sp1/c-Jun complex formation in melanoma cells, suggesting these complexes were involved in p21 promoter activation. Elucidating the mechanisms involved in the regulation of p21 expression in response to Fe chelator treatment in neoplastic cells will further clarify how these agents achieve their anti-tumor activity. It will also enhance our understanding of the complex roles p21 may play in neoplastic cells and lead to the development of more effective and specific anti-cancer therapies.
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Affiliation(s)
- Rayan S Moussa
- Molecular Pharmacology and Pathology Program, Discipline of Pathology and Bosch Institute, Medical Foundation Building (K25), The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Kyung Chan Park
- Molecular Pharmacology and Pathology Program, Discipline of Pathology and Bosch Institute, Medical Foundation Building (K25), The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Zaklina Kovacevic
- Molecular Pharmacology and Pathology Program, Discipline of Pathology and Bosch Institute, Medical Foundation Building (K25), The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Des R Richardson
- Molecular Pharmacology and Pathology Program, Discipline of Pathology and Bosch Institute, Medical Foundation Building (K25), The University of Sydney, Sydney, New South Wales 2006, Australia; Department of Pathology and Biological Responses, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya 466-8550, Japan.
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24
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Rani A, Stebbing J, Giamas G, Murphy J. Endocrine Resistance in Hormone Receptor Positive Breast Cancer-From Mechanism to Therapy. Front Endocrinol (Lausanne) 2019; 10:245. [PMID: 31178825 PMCID: PMC6543000 DOI: 10.3389/fendo.2019.00245] [Citation(s) in RCA: 141] [Impact Index Per Article: 28.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 03/28/2019] [Indexed: 12/24/2022] Open
Abstract
The importance and role of the estrogen receptor (ER) pathway has been well-documented in both breast cancer (BC) development and progression. The treatment of choice in women with metastatic breast cancer (MBC) is classically divided into a variety of endocrine therapies, 3 of the most common being: selective estrogen receptor modulators (SERM), aromatase inhibitors (AI) and selective estrogen receptor down-regulators (SERD). In a proportion of patients, resistance develops to endocrine therapy due to a sophisticated and at times redundant interference, at the molecular level between the ER and growth factor. The progression to endocrine resistance is considered to be a gradual, step-wise process. Several mechanisms have been proposed but thus far none of them can be defined as the complete explanation behind the phenomenon of endocrine resistance. Although multiple cellular, molecular and immune mechanisms have been and are being extensively studied, their individual roles are often poorly understood. In this review, we summarize current progress in our understanding of ER biology and the molecular mechanisms that predispose and determine endocrine resistance in breast cancer patients.
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Affiliation(s)
- Aradhana Rani
- School of Life Sciences, University of Westminster, London, United Kingdom
- *Correspondence: Aradhana Rani
| | - Justin Stebbing
- Department of Surgery and Cancer, Imperial College London, London, United Kingdom
| | - Georgios Giamas
- Department of Biochemistry and Biomedicine, School of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - John Murphy
- School of Life Sciences, University of Westminster, London, United Kingdom
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Disproportionate feedback interactions govern cell‐type specific proliferation in mammalian cells. FEBS Lett 2018; 592:3248-3263. [DOI: 10.1002/1873-3468.13241] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 08/17/2018] [Accepted: 09/03/2018] [Indexed: 11/07/2022]
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Nakamura M, Wu L, Griffin JD, Kojika S, Goi K, Inukai T, Sugita K. Notch1 activation enhances proliferation via activation of cdc2 and delays differentiation of myeloid progenitors. Leuk Res 2018; 72:34-44. [PMID: 30086426 DOI: 10.1016/j.leukres.2018.07.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 07/21/2018] [Accepted: 07/28/2018] [Indexed: 11/16/2022]
Abstract
Accumulating evidence indicates that the Notch signaling pathway has crucial roles in the control of fate decision and differentiation in numerous cell types. However, the role of Notch signaling in regulating proliferation and differentiation of myeloid progenitor cells remains controversial. To elucidate this issue, we modulated Notch activity through transducing a constitutively activated form of Notch1 and/or a dominant-negative form of MAML1 (DNMAML1) into myeloid progenitor 32D cells and assessed their effects on cell proliferation and differentiation. We found that Notch1 activation enhances proliferation and delays granulocytic differentiation of 32D cells. The enhanced proliferation due to activated Notch1 signaling was associated with upregulation of c-Myc, followed by decreased expression of p21 and p27, and increased cdc2 kinase activity, through a mechanism that was not blocked by DNMAML1. Conversely, Notch1 activation significantly delayed granulocytic differentiation and maintained a part of myeloid progenitor cells in an immature stage, and this Notch1-mediated effect was dependent on MAML. The Notch1-induced effects on mye myeloid cell proliferation and differentiation were likely mediated by induction of c-Myc and repression of PU.1, respectively. Thus, Notch1 signaling plays an important part in modulating proliferation and differentiation in MAML-independent and -dependent manners and promoting expansion of myeloid progenitors.
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Affiliation(s)
- Makoto Nakamura
- Department of Pediatrics, School of Medicine, University of Yamanashi, 1110 Shimokato, Chuo, Yamamashi 409-3898, Japan.
| | - Lizi Wu
- Department of Molecular Genetics and Microbiology, UF health Cancer Center, University of Florida, 1376 Mowry Rd, Gainesville, FL 32610-3363, United States
| | - James D Griffin
- Department of Medical Oncology, Dana-Farber Cancer Institute, Brigham and Women's Hospital and Harvard Medical School, 450 Brookline Avenue, Boston, MA 02215, United States
| | - Satoru Kojika
- Department of Pediatrics, School of Medicine, University of Yamanashi, 1110 Shimokato, Chuo, Yamamashi 409-3898, Japan
| | - Kumiko Goi
- Department of Pediatrics, School of Medicine, University of Yamanashi, 1110 Shimokato, Chuo, Yamamashi 409-3898, Japan
| | - Takeshi Inukai
- Department of Pediatrics, School of Medicine, University of Yamanashi, 1110 Shimokato, Chuo, Yamamashi 409-3898, Japan
| | - Kanji Sugita
- Department of Pediatrics, School of Medicine, University of Yamanashi, 1110 Shimokato, Chuo, Yamamashi 409-3898, Japan
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A dual role of miR-22 modulated by RelA/p65 in resensitizing fulvestrant-resistant breast cancer cells to fulvestrant by targeting FOXP1 and HDAC4 and constitutive acetylation of p53 at Lys382. Oncogenesis 2018; 7:54. [PMID: 30057418 PMCID: PMC6064715 DOI: 10.1038/s41389-018-0063-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 05/21/2018] [Indexed: 12/11/2022] Open
Abstract
Antiestrogen resistance is a major challenge encountered during the treatment of estrogen receptor alpha positive (ERα+) breast cancer. A better understanding of signaling pathways and downstream transcription factors and their targets may identify key molecules that can overcome antiestrogen resistance in breast cancer. An aberrant expression of miR-22 has been demonstrated in breast cancer; however, its contribution to breast cancer resistance to fulvestrant, an antiestrogen drug, remains unknown. In this study, we demonstrated a moderate elevation in miR-22 expression in the 182R-6 fulvestrant-resistant breast cancer line we used as a model system, and this elevation was positively correlated with the expression of the miRNA biogenesis enzymes AGO2 and Dicer. The level of phosphorylated HER2/neu at Tyr877 was also upregulated in these cells, whereas the level of RelA/p65 phosphorylated at Ser536 (p-p65) was downregulated. Knockdown of HER2/neu led to an induction of p-p65 and a reduction in miR-22 levels. Luciferase assays identified two NF-κB binding motifs in the miR-22 promoter that contributed to transcriptional repression of miR-22. Activation of RelA/p65, triggered by LPS, attenuated miR-22 expression, but this expression was restored by sc-514, a selective IKKβ inhibitor. Inhibition of miR-22 suppressed cell proliferation, induced apoptosis and caused cell cycle S-phase arrest, whereas enhancing expression of p21Cip1/Waf1 and p27Kip1. Surprisingly, ectopic expression of miR-22 also suppressed cell proliferation, induced apoptosis, caused S-phase arrest, and promoted the expression of p21Cip1/Waf1 and p27Kip1. Ectopic overexpression of miR-22 repressed the expression of FOXP1 and HDAC4, leading to a marked induction of acetylation of HDAC4 target histones. Conversely, inhibition of miR-22 promoted the expression of both FOXP1 and HDAC4, without the expected attenuation of histone acetylation. Instead, p53 acetylation at lysine 382 was unexpectedly upregulated. Taken together, our findings demonstrated, for the first time, that HER2 activation dephosphorylates RelA/p65 at Ser536. This dephosphoryalted p65 may be pivotal in transactivation of miR-22. Both increased and decreased miR-22 expression cause resensitization of fulvestrant-resistant breast cancer cells to fulvestrant. HER2/NF-κB (p65)/miR-22/HDAC4/p21 and HER2/NF-κB (p65)/miR-22/Ac-p53/p21 signaling circuits may therefore confer this dual role on miR-22 through constitutive transactivation of p21.
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Bado I, Pham E, Soibam B, Nikolos F, Gustafsson JÅ, Thomas C. ERβ alters the chemosensitivity of luminal breast cancer cells by regulating p53 function. Oncotarget 2018; 9:22509-22522. [PMID: 29854295 PMCID: PMC5976481 DOI: 10.18632/oncotarget.25147] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 03/21/2018] [Indexed: 01/13/2023] Open
Abstract
Estrogen receptor α (ERα)-positive breast cancers tend to develop resistance to both endocrine therapy and chemotherapy. Despite recent progress in defining molecular pathways that confer endocrine resistance, the mechanisms that regulate chemotherapy response in luminal tumors remain largely elusive. Luminal tumors often express wild-type p53 that is a major determinant of the cellular DNA damage response. Similar to p53, the second ER subtype, ERβ, has been reported to inhibit breast tumorigenesis by acting alone or in collaboration with p53. However, a synergistic mechanism of action has not been described. Here, we suggest that ERβ relies on p53 to elicit its tumor repressive actions in ERα-positive breast cancer cells. Upregulation of ERβ and treatment with ERβ agonists potentiates the tumor suppressor function of p53 resulting in decreased survival. This effect requires molecular interaction between the two proteins that disrupts the inhibitory action of ERα on p53 leading to increased transcriptional activity of p53. In addition, we show that the same interaction alters the chemosensitivity of endocrine-resistant cells including their response to tamoxifen therapy. Our results suggest a collaboration of ERβ and p53 tumor suppressor activity in breast cancer cells that indicates the importance of ligand-regulated ERβ as a tool to target p53 activity and improve the clinical management of resistant disease.
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Affiliation(s)
- Igor Bado
- Department of Biology and Biochemistry, Center for Nuclear Receptors and Cell Signaling, University of Houston, Houston, Texas, USA
| | - Eric Pham
- Department of Biology and Biochemistry, University of Houston, Houston, Texas, USA
| | - Benjamin Soibam
- Department of Computer Science and Engineering Technology, University of Houston-Downtown, Huston, Texas, USA
| | - Fotis Nikolos
- Department of Biology and Biochemistry, Center for Nuclear Receptors and Cell Signaling, University of Houston, Houston, Texas, USA
| | - Jan-Åke Gustafsson
- Department of Biology and Biochemistry, Center for Nuclear Receptors and Cell Signaling, University of Houston, Houston, Texas, USA
- Center for Innovative Medicine, Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - Christoforos Thomas
- Department of Biology and Biochemistry, Center for Nuclear Receptors and Cell Signaling, University of Houston, Houston, Texas, USA
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Rocca A, Schirone A, Maltoni R, Bravaccini S, Cecconetto L, Farolfi A, Bronte G, Andreis D. Progress with palbociclib in breast cancer: latest evidence and clinical considerations. Ther Adv Med Oncol 2017; 9:83-105. [PMID: 28203301 PMCID: PMC5298405 DOI: 10.1177/1758834016677961] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Deregulation of the cell cycle is a hallmark of cancer, and research on cell cycle control has allowed identification of potential targets for anticancer treatment. Palbociclib is a selective inhibitor of the cyclin-dependent kinases 4 and 6 (CDK4/6), which are involved, with their coregulatory partners cyclin D, in the G1-S transition. Inhibition of this step halts cell cycle progression in cells in which the involved pathway, including the retinoblastoma protein (Rb) and the E2F family of transcription factors, is functioning, although having been deregulated. Among breast cancers, those with functioning cyclin D-CDK4/6-Rb-E2F are mainly hormone-receptor (HR) positive, with some HER2-positive and rare triple-negative cases. Deregulation results from genetic or otherwise occurring hyperactivation of molecules subtending cell cycle progression, or inactivation of cell cycle inhibitors. Based on results of randomized clinical trials, palbociclib was granted accelerated approval by the US Food and Drug Administration (FDA) for use in combination with letrozole as initial endocrine-based therapy for metastatic disease in postmenopausal women with HR-positive, HER2-negative breast cancer, and was approved for use in combination with fulvestrant in women with HR-positive, HER2-negative advanced breast cancer with disease progression following endocrine therapy. This review provides an update of the available knowledge on the cell cycle and its regulation, on the alterations in cyclin D-CDK4/6-Rb-E2F axis in breast cancer and their roles in endocrine resistance, on the preclinical activity of CDK4/6 inhibitors in breast cancer, both as monotherapy and as partners of combinatorial synergic treatments, and on the clinical development of palbociclib in breast cancer.
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Affiliation(s)
- Andrea Rocca
- Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Via Maroncelli 40, Meldola, FC 47014, Italy
| | - Alessio Schirone
- Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, FC, Italy
| | - Roberta Maltoni
- Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, FC, Italy
| | - Sara Bravaccini
- Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, FC, Italy
| | - Lorenzo Cecconetto
- Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, FC, Italy
| | - Alberto Farolfi
- Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, FC, Italy
| | - Giuseppe Bronte
- Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, FC, Italy
| | - Daniele Andreis
- Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, FC, Italy
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SCFFbl12 Increases p21Waf1/Cip1 Expression Level through Atypical Ubiquitin Chain Synthesis. Mol Cell Biol 2016; 36:2182-94. [PMID: 27215384 DOI: 10.1128/mcb.00174-16] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 05/17/2016] [Indexed: 11/20/2022] Open
Abstract
The cyclin-dependent kinase (CDK) inhibitor p21 is an unstructured protein regulated by multiple turnover pathways. p21 abundance is tightly regulated, and its defect causes tumor development. However, the mechanisms that underlie the control of p21 level are not fully understood. Here, we report a novel mechanism by which a component of the SCF ubiquitin ligase, Fbl12, augments p21 via the formation of atypical ubiquitin chains. We found that Fbl12 binds and ubiquitinates p21. Unexpectedly, Fbl12 increases the expression level of p21 by enhancing the mixed-type ubiquitination, including not only K48- but also K63-linked ubiquitin chains, followed by promotion of binding between p21 and CDK2. We also found that proteasome activator PA28γ attenuates p21 ubiquitination by interacting with Fbl12. In addition, UV irradiation induces a dissociation of p21 from Fbl12 and decreases K63-linked ubiquitination, leading to p21 degradation. These data suggest that Fbl12 is a key factor that maintains adequate intracellular concentration of p21 under normal conditions. Our finding may provide a novel possibility that p21's fate is governed by diverse ubiquitin chains.
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O'Sullivan CC. CDK4/6 inhibitors for the treatment of advanced hormone receptor positive breast cancer and beyond: 2016 update. Expert Opin Pharmacother 2016; 17:1657-67. [PMID: 27322766 DOI: 10.1080/14656566.2016.1201072] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
INTRODUCTION Breast cancer remains a major cause of morbidity and mortality worldwide. Given the central role of cyclin-dependent kinases in regulating cell division, there has been a longstanding interest in developing compounds which target the cyclin D1: CDK4/6 axis in breast cancer. The recent discovery of potent and selective CDK4/6 inhibitors (CDK4/6i) was an important breakthrough. AREAS COVERED There are three CDK4/6i in clinical development (palbociclib, ribociclib and abemaciclib). Phase II and III studies using palbociclib in combination with endocrine therapy demonstrated remarkable clinical activity in women with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced breast cancer, resulting in two separate FDA approvals in 2015 and 2016. In this article, we review the preclinical and clinical development of these compounds as well as discussing the role for novel applications of these agents outside the arena of HR-positive, HER2-negative advanced breast cancer. EXPERT OPINION In combination with endocrine therapy, CDK4/6i have shown promising efficacy in patients with advanced HR-positive, HER2-negative advanced breast cancer. Numerous trials in a variety of clinical settings and in different tumor types are ongoing or planned.
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32
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Zhang Q, Song Y, Chen W, Wang X, Miao Z, Cao L, Li F, Wang G. By recruiting HDAC1, MORC2 suppresses p21 Waf1/Cip1 in gastric cancer. Oncotarget 2016; 6:16461-70. [PMID: 26098774 PMCID: PMC4599282 DOI: 10.18632/oncotarget.3889] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 04/25/2015] [Indexed: 11/25/2022] Open
Abstract
Microrchidia (MORC) family CW-type zinc-finger 2 (MORC2) regulates chromatin remodeling during the DNA-damage response, represses gene transcription, promotes lipogenesis. Here, we found that MORC2 down-regulated p21 by recruiting HDAC1 to the p21 promoter, in a p53-independent manner. MORC2-mediated down-regulation of p21 in turn promoted cell cycle progression in gastric cancer cells. Furthermore, MORC2 expression correlated negatively with p21 expression in gastric tumors in patients. We suggest that MORC2 may be a potential therapeutic target in cancer.
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Affiliation(s)
- Qing Zhang
- Department of Cell Biology, Key Laboratory of Cell Biology, Ministry of Public Health, and Key Laboratory of Medical Cell Biology, Ministry of Education, China Medical University, Shenyang, China
| | - Yanyan Song
- Department of Cell Biology, Key Laboratory of Cell Biology, Ministry of Public Health, and Key Laboratory of Medical Cell Biology, Ministry of Education, China Medical University, Shenyang, China
| | - Wei Chen
- Department of Cell Biology, Key Laboratory of Cell Biology, Ministry of Public Health, and Key Laboratory of Medical Cell Biology, Ministry of Education, China Medical University, Shenyang, China
| | - Xiaohui Wang
- Department of Cell Biology, Key Laboratory of Cell Biology, Ministry of Public Health, and Key Laboratory of Medical Cell Biology, Ministry of Education, China Medical University, Shenyang, China
| | - Zhifeng Miao
- Department of Surgical Oncology and General Surgery, First Hospital of China Medical University, Shenyang, China
| | - Liu Cao
- Department of Cell Biology, Key Laboratory of Cell Biology, Ministry of Public Health, and Key Laboratory of Medical Cell Biology, Ministry of Education, China Medical University, Shenyang, China
| | - Feng Li
- Department of Cell Biology, Key Laboratory of Cell Biology, Ministry of Public Health, and Key Laboratory of Medical Cell Biology, Ministry of Education, China Medical University, Shenyang, China
| | - Guiling Wang
- Department of Cell Biology, Key Laboratory of Cell Biology, Ministry of Public Health, and Key Laboratory of Medical Cell Biology, Ministry of Education, China Medical University, Shenyang, China
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Salari Fanoodi T, Motalleb G, Yegane Moghadam A, Talaee R. p21 Gene Expression Evaluation in Esophageal Cancer Patients. Gastrointest Tumors 2015. [DOI: 10.1159/000441901] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Walter W, Thomalla J, Bruhn J, Fagan DH, Zehowski C, Yee D, Skildum A. Altered regulation of PDK4 expression promotes antiestrogen resistance in human breast cancer cells. SPRINGERPLUS 2015; 4:689. [PMID: 26576332 PMCID: PMC4641142 DOI: 10.1186/s40064-015-1444-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 10/19/2015] [Indexed: 11/10/2022]
Abstract
Acquired or de novo resistance to the selective estrogen receptor modulators tamoxifen and fulvestrant (ICI) is a major barrier to successful treatment of breast cancer. Gene expression patterns in tamoxifen resistant (TamR-MCF-7) cells were compared to their parental cells (MCF-7L) to identify an aberrantly regulated metabolic pathway. TamR-MCF-7 cells are cross resistant to ICI and doxorubicin, and have increased mitochondrial DNA. A small subset of genes had altered expression in TamR-MCF-7 relative to MCF-7L cells. One of the genes, pyruvate dehydrogenase kinase-4 (PDK4), phosphorylates pyruvate dehydrogenase (PDH). PDK4 expression was elevated in TamR-MCF-7 cells; this result was also observed in a second model of acquired antiestrogen resistance. PDK4 expression is controlled in part by glucocorticoid response elements in the PDK4 gene promoter. In MCF-7L cells, PDK4 mRNA expression was insensitive to glucocorticoid receptor agonists, while dexamethasone dramatically increased PDK4 expression in TamR-MCF-7 cells. Using siRNA to knock down PDK4 expression increased TamR-MCF-7 sensitivity to ICI; in contrast adapting cells to growth in glucose depleted media did not affect ICI sensitivity. Despite TamR-MCF-7 cells high levels of PDK4 mRNA relative to MCF-7L, TamR-MCF-7 cells have increased PDH activity. Wild type MCF-7 cells are reported to be heterozygous for a G to A mutation that results in a substitution of threonine for alanine near PDK4′s catalytic site. We found loss of heterozygosity in TamR-MCF-7 cells; TamR-MCF-7 are homozygous for the wild type allele. These data support a role for altered regulation of PDH by PDK4 and altered substrate utilization in the development of drug resistance in human breast cancer cells.
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Affiliation(s)
- William Walter
- Department of Biomedical Sciences, University of Minnesota Medical School, Duluth Campus, Duluth, MN USA
| | - Jennifer Thomalla
- Department of Biomedical Sciences, University of Minnesota Medical School, Duluth Campus, Duluth, MN USA
| | - Josh Bruhn
- Department of Biomedical Sciences, University of Minnesota Medical School, Duluth Campus, Duluth, MN USA
| | - Dedra H Fagan
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN USA
| | - Cheryl Zehowski
- Department of Biomedical Sciences, University of Minnesota Medical School, Duluth Campus, Duluth, MN USA
| | - Douglas Yee
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN USA
| | - Andrew Skildum
- Department of Biomedical Sciences, University of Minnesota Medical School, Duluth Campus, Duluth, MN USA ; Masonic Cancer Center, University of Minnesota, Minneapolis, MN USA
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Jin K, Park S, Teo WW, Korangath P, Cho SS, Yoshida T, Győrffy B, Goswami CP, Nakshatri H, Cruz LA, Zhou W, Ji H, Su Y, Ekram M, Wu Z, Zhu T, Polyak K, Sukumar S. HOXB7 Is an ERα Cofactor in the Activation of HER2 and Multiple ER Target Genes Leading to Endocrine Resistance. Cancer Discov 2015; 5:944-59. [PMID: 26180042 DOI: 10.1158/2159-8290.cd-15-0090] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Accepted: 07/01/2015] [Indexed: 11/16/2022]
Abstract
UNLABELLED Why breast cancers become resistant to tamoxifen despite continued expression of the estrogen receptor-α (ERα) and what factors are responsible for high HER2 expression in these tumors remains an enigma. HOXB7 chromatin immunoprecipitation analysis followed by validation showed that HOXB7 physically interacts with ERα, and that the HOXB7-ERα complex enhances transcription of many ERα target genes, including HER2. Investigating strategies for controlling HOXB7, our studies revealed that MYC, stabilized via phosphorylation mediated by EGFR-HER2 signaling, inhibits transcription of miR-196a, a HOXB7 repressor. This leads to increased expression of HOXB7, ER target genes, and HER2. Repressing MYC using small-molecule inhibitors reverses these events and causes regression of breast cancer xenografts. The MYC-HOXB7-HER2 signaling pathway is eminently targetable in endocrine-resistant breast cancer. SIGNIFICANCE HOXB7 acts as an ERα cofactor regulating a myriad of ER target genes, including HER2, in tamoxifen-resistant breast cancer. HOXB7 expression is controlled by MYC via transcriptional regulation of the HOXB7 repressor miR-196a; consequently, antagonists of MYC cause reversal of selective ER modulator resistance both in vitro and in vivo.
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Affiliation(s)
- Kideok Jin
- Breast Cancer Program, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Sunju Park
- Breast Cancer Program, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Wei Wen Teo
- Breast Cancer Program, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Preethi Korangath
- Breast Cancer Program, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Sean Soonweng Cho
- Breast Cancer Program, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Takahiro Yoshida
- Breast Cancer Program, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Balázs Győrffy
- MTA TTK Lendület Cancer Biomarker Research Group and 2nd Department of Pediatrics, Semmelweis University, Budapest, Hungary
| | - Chirayu Pankaj Goswami
- Center for Computational Biology and Bioinformatics, Indiana University, Bloomington, Indiana
| | - Harikrishna Nakshatri
- Center for Computational Biology and Bioinformatics, Indiana University, Bloomington, Indiana
| | - Leigh-Ann Cruz
- Breast Cancer Program, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Weiqiang Zhou
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Hongkai Ji
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Ying Su
- Dana-Farber Cancer Institute, Boston, Massachusetts
| | | | - Zhengsheng Wu
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, People's Republic of China
| | - Tao Zhu
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, People's Republic of China
| | | | - Saraswati Sukumar
- Breast Cancer Program, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland.
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Xu J, Chen Y, Huo D, Khramtsov A, Khramtsova G, Zhang C, Goss KH, Olopade OI. β-catenin regulates c-Myc and CDKN1A expression in breast cancer cells. Mol Carcinog 2015; 55:431-9. [PMID: 25663530 DOI: 10.1002/mc.22292] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Revised: 12/17/2014] [Accepted: 12/30/2014] [Indexed: 02/01/2023]
Abstract
We previously reported that the Wnt pathway is preferentially activated in basal-like breast cancer. However, the mechanisms by which the Wnt pathway regulates down-stream targets in basal-like breast cancer, and the biological significance of this regulation, are poorly understood. In this study, we found that c-Myc is highly expressed in the basal-like subtype by microarray analyses and immunohistochemical staining. After silencing β-catenin using siRNA, c-Myc expression was decreased in non-basal-like breast cancer cells. In contrast, c-Myc mRNA and protein expression were up-regulated in the basal-like breast cancer cell lines. Decreased c-Myc promoter activity was observed after inhibiting β-catenin by siRNA in non-basal-like breast cancer cells; however, inhibition of β-catenin or over-expression of dominant-negative LEF1 had no effect on c-Myc promoter activity in basal-like breast cancer cell lines. In addition, CDKN1A mRNA and p21 protein expression were significantly increased in all breast cancer cell lines upon β-catenin silencing. Interestingly, inhibiting β-catenin expression alone did not induce apoptosis in breast cancer cell lines despite c-Myc regulation, but we observed a modest increase of cells in the G1 phase of the cell cycle and decrease of cells in S phase upon β-catenin silencing. Our findings suggest that the regulation of c-Myc in breast cancer cells is dependent on the molecular subtype, and that β-catenin-mediated regulation of c-Myc and p21 may control the balance of cell death and proliferation in breast cancer.
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Affiliation(s)
- Jinhua Xu
- Section of Hematology/Oncology, Department of Medicine, University of Chicago, Chicago,, Illinois.,School of Medicine, Jianghan University, Wuhan, Hubei, P. R. China
| | - Yinghua Chen
- Section of Hematology/Oncology, Department of Medicine, University of Chicago, Chicago,, Illinois
| | - Dezheng Huo
- Department of Public Health Sciences, University of Chicago, Chicago, Illinois
| | - Andrey Khramtsov
- Section of Hematology/Oncology, Department of Medicine, University of Chicago, Chicago,, Illinois
| | - Galina Khramtsova
- Section of Hematology/Oncology, Department of Medicine, University of Chicago, Chicago,, Illinois
| | - Chunling Zhang
- Section of Hematology/Oncology, Department of Medicine, University of Chicago, Chicago,, Illinois
| | - Kathleen H Goss
- University of Chicago Comprehensive Cancer Center, University of Chicago, Chicago, Illinois
| | - Olufunmilayo I Olopade
- Section of Hematology/Oncology, Department of Medicine, University of Chicago, Chicago,, Illinois.,Department of Human Genetics, University of Chicago, Chicago, Illinois
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Blockade of estrogen-stimulated proliferation by a constitutively-active prolactin receptor having lower expression in invasive ductal carcinoma. Cancer Lett 2014; 358:152-160. [PMID: 25527452 DOI: 10.1016/j.canlet.2014.12.031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Revised: 12/11/2014] [Accepted: 12/12/2014] [Indexed: 11/22/2022]
Abstract
A comprehensive understanding of prolactin's (PRL's) role in breast cancer is complicated by disparate roles for alternatively-spliced PRL receptors (PRLR) and crosstalk between PRL and estrogen signaling. Among PRLRs, the short form 1b (SF1b) inhibits PRL-stimulated cell proliferation. In addition to ligand-dependent PRLRs, constitutively-active varieties, missing the S2 region of the extracellular domain (ΔS2), naturally occur. Expression analysis of the ΔS2 version of SF1b (ΔS2SF1b) showed higher expression in histologically-normal contiguous tissue versus invasive ductal carcinoma. To determine the function of ΔS2SF1b, a T47D breast cancer line with inducible expression was produced. Induction of ΔS2SF1b blocked estrogen-stimulated cell proliferation. Unlike intact SF1b, induction of ΔS2SF1b had no effect on PRL-mediated activation of Stat5a. However induction inhibited estrogen's stimulatory effects on serine-118 phosphorylation of estrogen receptor α, serine-473 phosphorylation of Akt, serine-9 phosphorylation of GSK3β, and c-myc expression. In addition, induction of ΔS2SF1b increased expression of the cell cycle-inhibiting protein, p21. Thus, increased expression of ΔS2SF1b, such as we demonstrate occurs with the selective PRLR modulator, S179D PRL, would create a physiological state in which estrogen-stimulated proliferation was inhibited, but differentiative responses to PRL were maintained.
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HUANG OU, XIE ZUOQUAN, ZHANG WEILI, LOU YING, MAO YAN, LIU HONGCHUN, JIANG MIN, SHEN KUNWEI. A771726, an anti-inflammatory drug, exerts an anticancer effect and reverses tamoxifen resistance in endocrine-resistant breast cancer cells. Oncol Rep 2014; 32:627-34. [DOI: 10.3892/or.2014.3249] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Accepted: 05/21/2014] [Indexed: 11/06/2022] Open
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Tan S, Ding K, Li R, Zhang W, Li G, Kong X, Qian P, Lobie PE, Zhu T. Identification of miR-26 as a key mediator of estrogen stimulated cell proliferation by targeting CHD1, GREB1 and KPNA2. Breast Cancer Res 2014; 16:R40. [PMID: 24735615 PMCID: PMC4053242 DOI: 10.1186/bcr3644] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 03/28/2014] [Indexed: 02/07/2023] Open
Abstract
Introduction Estrogen signaling is pivotal in the progression of estrogen receptor positive breast cancer primarily by the regulation of cell survival and proliferation. Micro (mi)RNAs have been demonstrated to be regulated by estrogen to mediate estrogenic effects. Herein, we determined the role of estrogen regulated miR-26 and its underlying molecular mechanisms associated with estrogen receptor (ER)+ breast cancer proliferation. Methods The expression of miR-26a and miR-26b was evaluated by real-time quantitative (RT)-PCR. The expression of miR-26a or miR-26b was modulated in ER+ breast cancer cells (MCF-7 and T47D) and tumor cell growth in vitro and an in vivo xenograft model was determined. Bioinformatics analyses were utilized to screen for estrogen responsive genes, which were also predicted to be targeted by miR-26. Luciferase reporter assays were performed to confirm miR-26 regulation of the 3' UTR of target genes. The levels of miR-26 target genes (CHD1, GREB1 and KPNA2) were evaluated by western blotting and immunohistochemistry. Results Estrogen reduced the expression of miR-26a and miR-26b in ER+ breast cancer cells. Forced expression of miR-26a or miR-26b significantly inhibited the estrogen stimulated growth of ER+ breast cancer cells and tumor growth in xenograft models, whereas miR-26a/b depletion increased the growth of ER+ breast cancer cells in the absence of estrogen treatment. Screening of estrogen responsive genes, which were also predicted to be targeted by miR-26, identified GREB1 and nine other genes (AGPAT5, AMMECR1, CHD1, ERLIN1, HSPA8, KPNA2, MREG, NARG1, and PLOD2). Further verification has identified nine genes (AGPAT5, CHD1, ERLIN1, GREB1, HSPA8, KPNA2, MREG, NARG1 and PLOD2) which were directly targeted by miR-26 via their 3′ UTR. Functional screening suggested only three estrogen regulated miR-26 target genes (CHD1, GREB1 and KPNA2) were involved in the regulation of estrogen promoted cell proliferation. Depletion of either CHD1, GREB1 or KPNA2 significantly abrogated the enhanced growth of ER+ breast cancer cells due to miR-26 depletion. We further demonstrated that estrogen stimulated c-MYC expression was both sufficient and necessary for the diminished expression of miR-26a and miR-26b. Conclusions We have identified a novel estrogen/MYC/miR-26 axis that mediates estrogen stimulated cell growth via CHD1, GREB1 and KPNA2.
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Sengupta D, Bhargava DK, Dixit A, Sahoo BS, Biswas S, Biswas G, Mishra SK. ERRβ signalling through FST and BCAS2 inhibits cellular proliferation in breast cancer cells. Br J Cancer 2014; 110:2144-58. [PMID: 24667650 PMCID: PMC3992508 DOI: 10.1038/bjc.2014.53] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Revised: 11/06/2013] [Accepted: 01/13/2014] [Indexed: 12/11/2022] Open
Abstract
Background: The overexpression of oestrogen-related receptor-β (ERRβ) in breast cancer patients is correlated with improved prognosis and longer relapse-free survival, and the level of ERRβ mRNA is inversely correlated with the S-phase fraction of cells from breast cancer patients. Methods: Chromatin immunoprecipitation (ChIP) cloning of ERRβ transcriptional targets and gel supershift assays identified breast cancer amplified sequence 2 (BCAS2) and Follistatin (FST) as two important downstream genes that help to regulate tumourigenesis. Confocal microscopy, co-immunoprecipitation (CoIP), western blotting and quantitative real-time PCR confirmed the involvement of ERRβ in oestrogen signalling. Results: Overexpressed ERRβ induced FST-mediated apoptosis in breast cancer cells, and E-cadherin expression was also enhanced through upregulation of FST. However, this anti-proliferative signalling function was challenged by ERRβ-mediated BCAS2 upregulation, which inhibited FST transcription through the downregulation of β-catenin/TCF4 recruitment to the FST promoter. Interestingly, ERRβ-mediated upregulation of BCAS2 downregulated the major G1-S transition marker cyclin D1, despite the predictable oncogenic properties of BCAS2. Interpretation: Our study provides the first evidence that ERRβ, which is a coregulator of ERα also acts as a potential tumour-suppressor molecule in breast cancer. Our current report also provides novel insights into the entire cascade of ERRβ signalling events, which may lead to BCAS2-mediated blockage of the G1/S transition and inhibition of the epithelial to mesenchymal transition through FST-mediated regulation of E-cadherin. Importantly, matrix metalloprotease 7, which is a classical mediator of metastasis and E-cadherin cleavage, was also restricted as a result of ERRβ-mediated FST overexpression.
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Affiliation(s)
- D Sengupta
- Cancer Biology Laboratory, Department of Gene Function and Regulation, Institute of Life Sciences (an Institute under the Department of Biotechnology, Government of India), Nalco Square, Chandrasekharpur, Bhubaneswar, Odisha 751023, India
| | - D K Bhargava
- Cancer Biology Laboratory, Department of Gene Function and Regulation, Institute of Life Sciences (an Institute under the Department of Biotechnology, Government of India), Nalco Square, Chandrasekharpur, Bhubaneswar, Odisha 751023, India
| | - A Dixit
- Drug Design and Discovery, Department of Translational Research and Technology Development, Institute of Life Sciences (an Institute under the Department of Biotechnology, Government of India), Nalco Square, Chandrasekharpur, Bhubaneswar, Odisha 751023, India
| | - B S Sahoo
- Confocal Microscopic Facility, Institute of Life Sciences (an Institute under the Department of Biotechnology, Government of India), Nalco Square, Chandrasekharpur, Bhubaneswar, Odisha 751023, India
| | - S Biswas
- Department of Pathology, Sparsh Hospitals and Critical Care, A/407, Saheed Nagar, Bhubaneswar, Odisha 751007, India
| | - G Biswas
- Department of Medical Oncology, Sparsh Hospitals and Critical Care, A/407, Saheed Nagar, Bhubaneswar, Odisha 751007, India
| | - S K Mishra
- Cancer Biology Laboratory, Department of Gene Function and Regulation, Institute of Life Sciences (an Institute under the Department of Biotechnology, Government of India), Nalco Square, Chandrasekharpur, Bhubaneswar, Odisha 751023, India
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Wang PC, Weng CC, Hou YS, Jian SF, Fang KT, Hou MF, Cheng KH. Activation of VCAM-1 and its associated molecule CD44 leads to increased malignant potential of breast cancer cells. Int J Mol Sci 2014; 15:3560-79. [PMID: 24583847 PMCID: PMC3975354 DOI: 10.3390/ijms15033560] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2013] [Revised: 01/30/2014] [Accepted: 02/14/2014] [Indexed: 12/14/2022] Open
Abstract
VCAM-1 (CD106), a transmembrane glycoprotein, was first reported to play an important role in leukocyte adhesion, leukocyte transendothelial migration and cell activation by binding to integrin VLA-1 (α4β1). In the present study, we observed that VCAM-1 expression can be induced in many breast cancer epithelial cells by cytokine stimulation in vitro and its up-regulation directly correlated with advanced clinical breast cancer stage. We found that VCAM-1 over-expression in the NMuMG breast epithelial cells controls the epithelial and mesenchymal transition (EMT) program to increase cell motility rates and promote chemoresistance to doxorubicin and cisplatin in vitro. Conversely, in the established MDAMB231 metastatic breast cancer cell line, we confirmed that knockdown of endogenous VCAM-1 expression reduced cell proliferation and inhibited TGFβ1 or IL-6 mediated cell migration, and increased chemosensitivity. Furthermore, we demonstrated that knockdown of endogenous VCAM-1 expression in MDAMB231 cells reduced tumor formation in a SCID xenograft mouse model. Signaling studies showed that VCAM-1 physically associates with CD44 and enhances CD44 and ABCG2 expression. Our findings uncover the possible mechanism of VCAM-1 activation facilitating breast cancer progression, and suggest that targeting VCAM-1 is an attractive strategy for therapeutic intervention.
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Affiliation(s)
- Pei-Chen Wang
- Institute of Biomedical Science, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan.
| | - Ching-Chieh Weng
- Institute of Biomedical Science, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan.
| | - You-Syuan Hou
- Institute of Biomedical Science, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan.
| | - Shu-Fang Jian
- Institute of Biomedical Science, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan.
| | - Kuan-Te Fang
- Department of Research and Development, Eternal Chemical Co., Ltd., Kaohsiung 80778, Taiwan.
| | - Ming-Feng Hou
- Department of Surgery, Kaohsiung Medical University Chung-Ho Memorial Hospital, Kaohsiung 80708, Taiwan.
| | - Kuang-Hung Cheng
- Institute of Biomedical Science, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan.
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Kang J, Sergio CM, Sutherland RL, Musgrove EA. Targeting cyclin-dependent kinase 1 (CDK1) but not CDK4/6 or CDK2 is selectively lethal to MYC-dependent human breast cancer cells. BMC Cancer 2014; 14:32. [PMID: 24444383 PMCID: PMC3903446 DOI: 10.1186/1471-2407-14-32] [Citation(s) in RCA: 110] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2013] [Accepted: 01/08/2014] [Indexed: 02/06/2023] Open
Abstract
Background Although MYC is an attractive therapeutic target for breast cancer treatment, it has proven challenging to inhibit MYC directly, and clinically effective pharmaceutical agents targeting MYC are not yet available. An alternative approach is to identify genes that are synthetically lethal in MYC-dependent cancer. Recent studies have identified several cell cycle kinases as MYC synthetic-lethal genes. We therefore investigated the therapeutic potential of specific cyclin-dependent kinase (CDK) inhibition in MYC-driven breast cancer. Methods Using small interfering RNA (siRNA), MYC expression was depleted in 26 human breast cancer cell lines and cell proliferation evaluated by BrdU incorporation. MYC-dependent and MYC-independent cell lines were classified based on their sensitivity to siRNA-mediated MYC knockdown. We then inhibited CDKs including CDK4/6, CDK2 and CDK1 individually using either RNAi or small molecule inhibitors, and compared sensitivity to CDK inhibition with MYC dependence in breast cancer cells. Results Breast cancer cells displayed a wide range of sensitivity to siRNA-mediated MYC knockdown. The sensitivity was correlated with MYC protein expression and MYC phosphorylation level. Sensitivity to siRNA-mediated MYC knockdown did not parallel sensitivity to the CDK4/6 inhibitor PD0332991; instead MYC-independent cell lines were generally sensitive to PD0332991. Cell cycle arrest induced by MYC knockdown was accompanied by a decrease in CDK2 activity, but inactivation of CDK2 did not selectively affect the viability of MYC-dependent breast cancer cells. In contrast, CDK1 inactivation significantly induced apoptosis and reduced viability of MYC-dependent cells but not MYC- independent cells. This selective induction of apoptosis by CDK1 inhibitors was associated with up-regulation of the pro-apoptotic molecule BIM and was p53-independent. Conclusions Overall, these results suggest that further investigation of CDK1 inhibition as a potential therapy for MYC-dependent breast cancer is warranted.
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Affiliation(s)
| | | | | | - Elizabeth A Musgrove
- The Kinghorn Cancer Centre and Cancer Research Division, Garvan Institute of Medical Research, 370 Victoria Street, Darlinghurst, Sydney, NSW, Australia.
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Rocca A, Farolfi A, Bravaccini S, Schirone A, Amadori D. Palbociclib (PD 0332991) : targeting the cell cycle machinery in breast cancer. Expert Opin Pharmacother 2013; 15:407-20. [PMID: 24369047 DOI: 10.1517/14656566.2014.870555] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
INTRODUCTION The cyclin D-cyclin-dependent kinases 4 and 6 (CDK4/6)-retinoblastoma (Rb) pathway, governing the cell cycle restriction point, is frequently altered in breast cancer and is a potentially relevant target for anticancer therapy. Palbociclib (PD 0332991) , a potent and selective inhibitor of CDK4 and CDK6, inhibits proliferation of several Rb-positive cancer cell lines and xenograft models. AREAS COVERED The basic features and abnormalities of the cell cycle in breast cancer are described, along with their involvement in estrogen signaling and endocrine resistance. The pharmacological features of palbociclib, its activity in preclinical models of breast cancer and the potential determinants of response are then illustrated, and its clinical development in breast cancer described. A literature search on the topic was conducted through PubMed and the proceedings of the main cancer congresses of recent years. EXPERT OPINION The combination of palbociclib with endocrine agents is a very promising treatment and Phase III clinical trials are ongoing to confirm its efficacy. Further, potentially useful combinations are those with drugs targeting mitogenic signaling pathways, such as HER2- and PI3K-inhibitors. Combination with chemotherapy seems more problematic, as antagonism has been reported in preclinical models. The identification of predictive factors, already explored in preclinical studies, must be further refined and validated in clinical trials.
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Affiliation(s)
- Andrea Rocca
- Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Department of Medical Oncology , Meldola , Italy +39 0543 739100 ; +39 0543 739151 ;
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Histone demethylase KDM5B collaborates with TFAP2C and Myc to repress the cell cycle inhibitor p21(cip) (CDKN1A). Mol Cell Biol 2012; 32:1633-44. [PMID: 22371483 DOI: 10.1128/mcb.06373-11] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The TFAP2C transcription factor has been shown to downregulate transcription of the universal cell cycle inhibitor p21(cip) (CDKN1A). In examining the mechanism of TFAP2C-mediated repression, we have identified a ternary complex at the proximal promoter containing TFAP2C, the oncoprotein Myc, and the trimethylated lysine 4 of histone H3 (H3K4me3) demethylase, KDM5B. We demonstrated that while TFAP2C and Myc can downregulate the CDKN1A promoter independently, KDM5B acts as a corepressor dependent on the other two proteins. All three factors collaborate for optimal CDKN1A repression, which requires the AP-2 binding site at -111/-103 and KDM5B demethylase activity. Silencing of TFAP2C-KDM5B-Myc led to increased H3K4me3 at the endogenous promoter and full induction of CDKN1A expression. Coimmunoprecipitation assays showed that TFAP2C and Myc associate with distinct domains of KDM5B and the TFAP2C C-terminal 270 amino acids (aa) are required for Myc and KDM5B interaction. Overexpression of all three proteins resulted in forced S-phase entry and attenuation of checkpoint activation, even in the presence of chemotherapy drugs. Since each protein has been linked to poor prognosis in breast cancer, our findings suggest that the TFAP2C-Myc-KDM5B complex promotes cell cycle progression via direct CDKN1A repression, thereby contributing to tumorigenesis and therapy failure.
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Lizarraga D, Gaj S, Brauers KJ, Timmermans L, Kleinjans JC, van Delft JHM. Benzo[a]pyrene-induced changes in microRNA-mRNA networks. Chem Res Toxicol 2012; 25:838-49. [PMID: 22316170 DOI: 10.1021/tx2003799] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Toxicological studies assessing the safety of compounds for humans frequently use in vitro systems to characterize toxic responses in combination with transcriptomic analyses. Thus far, changes have mostly been investigated at the mRNA level. Recently, microRNAs have attracted attention because they are powerful negative regulators of mRNA levels and, thus, may be responsible for the modulation of important mRNA networks implicated in toxicity. This study aimed to identify possible microRNA-mRNA networks as novel interactions on the gene expression level after a genotoxic insult. We used benzo[a]pyrene (BaP), a polycyclic aromatic hydrocarbon, as a model genotoxic/carcinogenic compound. We analyzed time-dependent effects on mRNA and microRNA profiles in HepG2 cells, a widely used human liver cell line that expresses active p53 and is competent for the biotransformation of BaP. Changes in microRNA expression in response to BaP, in combination with multiple alterations of mRNA levels, were observed. Many of these altered mRNAs are targets of altered microRNAs. Using pathway analysis, we evaluated the relevance of such microRNA deregulations to genotoxicity. This revealed eight microRNAs that appear to participate in specific BaP-responsive pathways relevant to genotoxicity, such as apoptotic signaling, cell cycle arrest, DNA damage response, and DNA damage repair. Our results particularly highlight the potential of microRNA-29b, microRNA-26a-1*, and microRNA-122* as novel players in the BaP response. Therefore, this study demonstrates the added value of an integrated microRNA-mRNA approach for identifying molecular mechanisms induced by BaP in an in vitro human model.
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Affiliation(s)
- Daneida Lizarraga
- Netherlands Toxicogenomics Centre, Maastricht University , P.O. Box 616, 6200 MD, Maastricht, The Netherlands
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Abstract
MYC is a key regulator of cell growth, proliferation, metabolism, differentiation, and apoptosis. MYC deregulation contributes to breast cancer development and progression and is associated with poor outcomes. Multiple mechanisms are involved in MYC deregulation in breast cancer, including gene amplification, transcriptional regulation, and mRNA and protein stabilization, which correlate with loss of tumor suppressors and activation of oncogenic pathways. The heterogeneity in breast cancer is increasingly recognized. Breast cancer has been classified into 5 or more subtypes based on gene expression profiles, and each subtype has distinct biological features and clinical outcomes. Among these subtypes, basal-like tumor is associated with a poor prognosis and has a lack of therapeutic targets. MYC is overexpressed in the basal-like subtype and may serve as a target for this aggressive subtype of breast cancer. Tumor suppressor BRCA1 inhibits MYC's transcriptional and transforming activity. Loss of BRCA1 with MYC overexpression leads to the development of breast cancer-especially, basal-like breast cancer. As a downstream effector of estrogen receptor and epidermal growth factor receptor family pathways, MYC may contribute to resistance to adjuvant therapy. Targeting MYC-regulated pathways in combination with inhibitors of other oncogenic pathways may provide a promising therapeutic strategy for breast cancer, the basal-like subtype in particular.
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Affiliation(s)
- Jinhua Xu
- Center for Clinical Cancer Genetics, Department of Medicine, University of Chicago, Chicago, IL, USA
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Partial inhibition of estrogen-induced mammary carcinogenesis in rats by tamoxifen: balance between oxidant stress and estrogen responsiveness. PLoS One 2011; 6:e25125. [PMID: 21966433 PMCID: PMC3180376 DOI: 10.1371/journal.pone.0025125] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2011] [Accepted: 08/25/2011] [Indexed: 11/19/2022] Open
Abstract
Epidemiological and experimental evidences strongly support the role of estrogens in breast tumor development. Both estrogen receptor (ER)-dependent and ER-independent mechanisms are implicated in estrogen-induced breast carcinogenesis. Tamoxifen, a selective estrogen receptor modulator is widely used as chemoprotectant in human breast cancer. It binds to ERs and interferes with normal binding of estrogen to ERs. In the present study, we examined the effect of long-term tamoxifen treatment in the prevention of estrogen-induced breast cancer. Female ACI rats were treated with 17β-estradiol (E2), tamoxifen or with a combination of E2 and tamoxifen for eight months. Tissue levels of oxidative stress markers 8-iso-Prostane F2α (8-isoPGF2α), superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase, and oxidative DNA damage marker 8-hydroxydeoxyguanosine (8-OHdG) were quantified in the mammary tissues of all the treatment groups and compared with age-matched controls. Levels of tamoxifen metabolizing enzymes cytochrome P450s as well as estrogen responsive genes were also quantified. At necropsy, breast tumors were detected in 44% of rats co-treated with tamoxifen+E2. No tumors were detected in the sham or tamoxifen only treatment groups whereas in the E2 only treatment group, the tumor incidence was 82%. Co-treatment with tamoxifen decreased GPx and catalase levels; did not completely inhibit E2-mediated oxidative DNA damage and estrogen-responsive genes monoamine oxygenase B1 (MaoB1) and cell death inducing DFF45 like effector C (Cidec) but differentially affected the levels of tamoxifen metabolizing enzymes. In summary, our studies suggest that although tamoxifen treatment inhibits estrogen-induced breast tumor development and increases the latency of tumor development, it does not completely abrogate breast tumor development in a rat model of estrogen-induced breast cancer. The inability of tamoxifen to completely inhibit E2-induced breast carcinogenesis may be because of increased estrogen-mediated oxidant burden.
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Zhen X, Cen J, Li YM, Yan F, Guan T, Tang XZ. Cytotoxic effect and apoptotic mechanism of tanshinone A, a novel tanshinone derivative, on human erythroleukemic K562 cells. Eur J Pharmacol 2011; 667:129-35. [DOI: 10.1016/j.ejphar.2011.06.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2010] [Revised: 05/22/2011] [Accepted: 06/06/2011] [Indexed: 12/21/2022]
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Akinyeke TO, Stewart LV. Troglitazone suppresses c-Myc levels in human prostate cancer cells via a PPARγ-independent mechanism. Cancer Biol Ther 2011; 11:1046-58. [PMID: 21525782 DOI: 10.4161/cbt.11.12.15709] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Troglitazone is a ligand for the peroxisome proliferator activated receptor gamma (PPARγ) that decreases growth of human prostate cancer cells in vitro and in vivo. However, the mechanism by which troglitazone reduces prostate cancer cell growth is not fully understood. To understand the signaling pathways involved in troglitazone-induced decreases in prostate cancer growth, we examined the effect of troglitazone on androgen-independent C4-2 human prostate cancer cells. Initial experiments revealed troglitazone inhibited C4-2 cell proliferation by arresting cells in the G(0)/G(1) phase of the cell cycle and inducing apoptosis. Since the proto-oncogene product c-Myc regulates both apoptosis and cell cycle progression, we next examined whether troglitazone altered expression of c-Myc. Troglitazone decreased c-Myc protein levels as well as expression of downstream targets of c-Myc in a dose-dependent manner. In C4-2 cells, troglitazone-induced decreases in c-Myc protein involve proteasome-mediated degradation of c-Myc protein as well as reductions in c-Myc mRNA levels. It appears that troglitazone stimulates degradation of c-Myc by increasing c-Myc phosphorylation, for the level of phosphorylated c-Myc was elevated in prostate cancer cells exposed to troglitazone. While troglitazone dramatically decreased the amount of c-Myc within C4-2 cells, the PPARγ ligands ciglitazone, rosiglitazone and pioglitazone did not reduce c-Myc protein levels. Furthermore the down-regulation of c-Myc by troglitazone was not blocked by the PPARγ antagonist GW9662 and siRNA-mediated decreases in PPARγ protein. Thus, our data suggest that troglitazone reduces c-Myc protein independently of PPARγ.
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Affiliation(s)
- Tunde O Akinyeke
- Department of Biochemistry and Cancer Biology, Meharry Medical College, Nashville, TN, USA
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Bouchet BP, Fauvet F, Grelier G, Galmarini CM, Puisieux A. p21(Cip1) regulates cell-substrate adhesion and interphase microtubule dynamics in untransformed human mammary epithelial cells. Eur J Cell Biol 2011; 90:631-41. [PMID: 21561680 DOI: 10.1016/j.ejcb.2011.03.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2010] [Revised: 03/01/2011] [Accepted: 03/07/2011] [Indexed: 12/19/2022] Open
Abstract
Despite its frequent inactivation in human breast cancers, the role of p21(Cip1) (p21) in morphological plasticity of normal mammary epithelial cells is still poorly understood. To address this question, we have investigated the consequences of p21 silencing in two-dimensional (2D) morphogenesis of untransformed human mammary epithelial cells. Here we show that p21 inactivation causes a reduction of 2D cell spreading and suppresses focal adhesion. In order to investigate the cytoskeletal modifications associated with this altered morphology, we have analyzed the microtubule dynamics in interphase p21-depleted cells. Our results demonstrate that interphase microtubule dynamic instability is strongly increased by p21 silencing. This alteration correlates with severe microtubule hypoacetylation. Next, we show that these microtubule defects in p21-depleted cells can be reversed by the use of the small molecule tubacin, a specific inhibitor of the α-tubulin deacetylase HDAC6. Tubacin-induced microtubule dynamics decrease also correlates with a partial recovery of cell spreading and focal adhesion in those cells. Collectively, these data indicate that p21 regulates the morphological plasticity of normal mammary epithelial cells by modulating dynamics of key cytoskeletal components.
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