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McGrath MK, Abolhassani A, Guy L, Elshazly AM, Barrett JT, Mivechi NF, Gewirtz DA, Schoenlein PV. Autophagy and senescence facilitate the development of antiestrogen resistance in ER positive breast cancer. Front Endocrinol (Lausanne) 2024; 15:1298423. [PMID: 38567308 PMCID: PMC10986181 DOI: 10.3389/fendo.2024.1298423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Accepted: 02/26/2024] [Indexed: 04/04/2024] Open
Abstract
Estrogen receptor positive (ER+) breast cancer is the most common breast cancer diagnosed annually in the US with endocrine-based therapy as standard-of-care for this breast cancer subtype. Endocrine therapy includes treatment with antiestrogens, such as selective estrogen receptor modulators (SERMs), selective estrogen receptor downregulators (SERDs), and aromatase inhibitors (AIs). Despite the appreciable remission achievable with these treatments, a substantial cohort of women will experience primary tumor recurrence, subsequent metastasis, and eventual death due to their disease. In these cases, the breast cancer cells have become resistant to endocrine therapy, with endocrine resistance identified as the major obstacle to the medical oncologist and patient. To combat the development of endocrine resistance, the treatment options for ER+, HER2 negative breast cancer now include CDK4/6 inhibitors used as adjuvants to antiestrogen treatment. In addition to the dysregulated activity of CDK4/6, a plethora of genetic and biochemical mechanisms have been identified that contribute to endocrine resistance. These mechanisms, which have been identified by lab-based studies utilizing appropriate cell and animal models of breast cancer, and by clinical studies in which gene expression profiles identify candidate endocrine resistance genes, are the subject of this review. In addition, we will discuss molecular targeting strategies now utilized in conjunction with endocrine therapy to combat the development of resistance or target resistant breast cancer cells. Of approaches currently being explored to improve endocrine treatment efficacy and patient outcome, two adaptive cell survival mechanisms, autophagy, and "reversible" senescence, are considered molecular targets. Autophagy and/or senescence induction have been identified in response to most antiestrogen treatments currently being used for the treatment of ER+ breast cancer and are often induced in response to CDK4/6 inhibitors. Unfortunately, effective strategies to target these cell survival pathways have not yet been successfully developed. Thus, there is an urgent need for the continued interrogation of autophagy and "reversible" senescence in clinically relevant breast cancer models with the long-term goal of identifying new molecular targets for improved treatment of ER+ breast cancer.
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Affiliation(s)
- Michael K. McGrath
- Georgia Cancer Center, Augusta University, Augusta, GA, United States
- Department of Cellular Biology & Anatomy, Medical College of Georgia at Augusta University, Augusta, GA, United States
| | - Ali Abolhassani
- Georgia Cancer Center, Augusta University, Augusta, GA, United States
- Department of Cellular Biology & Anatomy, Medical College of Georgia at Augusta University, Augusta, GA, United States
| | - Luke Guy
- Georgia Cancer Center, Augusta University, Augusta, GA, United States
- Department of Cellular Biology & Anatomy, Medical College of Georgia at Augusta University, Augusta, GA, United States
| | - Ahmed M. Elshazly
- Department of Pharmacology & Toxicology, Virginia Commonwealth University, Richmond, VA, United States
- Massey Comprehensive Cancer Center, Virginia Commonwealth University, Richmond, VA, United States
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Kafrelsheikh University, Kafrelsheikh, Egypt
| | - John T. Barrett
- Georgia Cancer Center, Augusta University, Augusta, GA, United States
- Department of Radiation Oncology, Georgia Cancer Center, Medical College of Georgia at Augusta University, Augusta, GA, United States
| | - Nahid F. Mivechi
- Georgia Cancer Center, Augusta University, Augusta, GA, United States
- Department of Radiation Oncology, Georgia Cancer Center, Medical College of Georgia at Augusta University, Augusta, GA, United States
| | - David A. Gewirtz
- Department of Pharmacology & Toxicology, Virginia Commonwealth University, Richmond, VA, United States
- Massey Comprehensive Cancer Center, Virginia Commonwealth University, Richmond, VA, United States
| | - Patricia V. Schoenlein
- Georgia Cancer Center, Augusta University, Augusta, GA, United States
- Department of Cellular Biology & Anatomy, Medical College of Georgia at Augusta University, Augusta, GA, United States
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2
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Yang R, Han Y, Guan X, Hong Y, Meng J, Ding S, Long Q, Yi W. Regulation and clinical potential of telomerase reverse transcriptase (TERT/hTERT) in breast cancer. Cell Commun Signal 2023; 21:218. [PMID: 37612721 PMCID: PMC10463831 DOI: 10.1186/s12964-023-01244-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 07/23/2023] [Indexed: 08/25/2023] Open
Abstract
Telomerase reverse transcriptase (TERT/hTERT) serves as the pivotal catalytic subunit of telomerase, a crucial enzyme responsible for telomere maintenance and human genome stability. The high activation of hTERT, observed in over 90% of tumors, plays a significant role in tumor initiation and progression. An in-depth exploration of hTERT activation mechanisms in cancer holds promise for advancing our understanding of the disease and developing more effective treatment strategies. In breast cancer, the expression of hTERT is regulated by epigenetic, transcriptional, post-translational modification mechanisms and DNA variation. Besides its canonical function in telomere maintenance, hTERT exerts non-canonical roles that contribute to disease progression through telomerase-independent mechanisms. This comprehensive review summarizes the regulatory mechanisms governing hTERT in breast cancer and elucidates the functional implications of its activation. Given the overexpression of hTERT in most breast cancer cells, the detection of hTERT and its associated molecules are potential for enhancing early screening and prognostic evaluation of breast cancer. Although still in its early stages, therapeutic approaches targeting hTERT and its regulatory molecules show promise as viable strategies for breast cancer treatment. These methods are also discussed in this paper. Video Abstract.
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Affiliation(s)
- Ruozhu Yang
- Department of General Surgery, the Second Xiangya Hospital of Central South University, 139 Middle Renmin Road, Changsha, 410011, China
| | - Yi Han
- Department of General Surgery, the Second Xiangya Hospital of Central South University, 139 Middle Renmin Road, Changsha, 410011, China
| | - Xinyu Guan
- Department of General Surgery, the Second Xiangya Hospital of Central South University, 139 Middle Renmin Road, Changsha, 410011, China
| | - Yue Hong
- Department of General Surgery, the Second Xiangya Hospital of Central South University, 139 Middle Renmin Road, Changsha, 410011, China
| | - Jiahao Meng
- Department of General Surgery, the Second Xiangya Hospital of Central South University, 139 Middle Renmin Road, Changsha, 410011, China
| | - Shirong Ding
- Department of Oncology, the Second Xiangya Hospital of Central South University, 139 Middle Renmin Road, Changsha, 410011, China.
| | - Qian Long
- Department of General Surgery, the Second Xiangya Hospital of Central South University, 139 Middle Renmin Road, Changsha, 410011, China.
| | - Wenjun Yi
- Department of General Surgery, the Second Xiangya Hospital of Central South University, 139 Middle Renmin Road, Changsha, 410011, China.
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3
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Long W, Zheng BX, Li Y, Huang XH, Lin DM, Chen CC, Hou JQ, Ou TM, Wong WL, Zhang K, Lu YJ. Rational design of small-molecules to recognize G-quadruplexes of c-MYC promoter and telomere and the evaluation of their in vivo antitumor activity against breast cancer. Nucleic Acids Res 2022; 50:1829-1848. [PMID: 35166828 PMCID: PMC8887543 DOI: 10.1093/nar/gkac090] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 01/20/2022] [Accepted: 01/27/2022] [Indexed: 12/31/2022] Open
Abstract
DNA G4-structures from human c-MYC promoter and telomere are considered as important drug targets; however, the developing of small-molecule-based fluorescent binding ligands that are highly selective in targeting these G4-structures over other types of nucleic acids is challenging. We herein report a new approach of designing small molecules based on a non-selective thiazole orange scaffold to provide two-directional and multi-site interactions with flanking residues and loops of the G4-motif for better selectivity. The ligands are designed to establish multi-site interactions in the G4-binding pocket. This structural feature may render the molecules higher selectivity toward c-MYC G4s than other structures. The ligand–G4 interaction studied with 1H NMR may suggest a stacking interaction with the terminal G-tetrad. Moreover, the intracellular co-localization study with BG4 and cellular competition experiments with BRACO-19 may suggest that the binding targets of the ligands in cells are most probably G4-structures. Furthermore, the ligands that either preferentially bind to c-MYC promoter or telomeric G4s are able to downregulate markedly the c-MYC and hTERT gene expression in MCF-7 cells, and induce senescence and DNA damage to cancer cells. The in vivo antitumor activity of the ligands in MCF-7 tumor-bearing mice is also demonstrated.
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Affiliation(s)
- Wei Long
- School of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou 510006, PR China
| | - Bo-Xin Zheng
- School of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou 510006, PR China
| | - Ying Li
- School of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou 510006, PR China
| | - Xuan-He Huang
- School of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou 510006, PR China
| | - Dan-Min Lin
- School of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou 510006, PR China
| | - Cui-Cui Chen
- School of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou 510006, PR China
| | - Jin-Qiang Hou
- Department of Chemistry, Lakehead University, 955 Oliver Road, Thunder Bay, Ontario P7B 5E1, Canada.,Thunder Bay Regional Health Research Institute, 980 Oliver Road, Thunder Bay, Ontario P7B 6V4, Canada
| | - Tian-Miao Ou
- Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou 510006, China
| | - Wing-Leung Wong
- State Key Laboratory of Chemical Biology and Drug Discovery, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Hong Kong SAR, China
| | - Kun Zhang
- School of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou 510006, PR China.,School of Biotechnology and Health Sciences, Wuyi University, Jiangmen, 529020, P.R. China; International Healthcare Innovation Institute (Jiangmen), Jiangmen, 529040, PR China
| | - Yu-Jing Lu
- School of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou 510006, PR China
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4
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Islam S, Dutta P, Sahay O, Gopalakrishnan K, Roy Muhury S, Parameshwar P, Shetty P, Santra MK. Feedback-regulated transcriptional repression of FBXO31 by c-Myc triggers ovarian cancer tumorigenesis. Int J Cancer 2021; 150:1512-1524. [PMID: 34706096 DOI: 10.1002/ijc.33854] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 07/30/2021] [Accepted: 09/02/2021] [Indexed: 11/08/2022]
Abstract
FBXO31, a member of F-box protein family, has been shown to play an important role in preventing tumorigenesis by preserving genomic stability during cell proliferations as well as upon genotoxic stresses. Inactivation of FBXO31 due to loss of heterozygosity is associated with various cancers, including ovarian cancer, one of the deadliest forms of gynecological cancers. However, the role and regulation of FBXO31 in ovarian cancer remained elusive. Here, using biochemical and molecular biology techniques, we show that c-Myc suppresses the mRNA levels of FBXO31 in ovarian cancer cell lines and mouse model. Chromatin immunoprecipitation experiment showed that c-Myc is recruited to the promoter region of FBXO31 and prevents FBXO31 mRNA synthesis. In contrast, FBXO31 maintains the c-Myc expression at an optimum through proteasome pathway. FBXO31 interacts with and facilitates the polyubiquitination of c-Myc through the SCF complex and thereby inhibits ovarian cancer growth both in vitro and in vivo. Moreover, FBXO31-mediated proteasomal degradation of c-Myc is unique. Unlike other negative regulators, FBXO31 recognizes c-Myc in phosphorylation independent manner to direct its degradation. Further, expression levels analysis revealed that c-Myc and FBXO31 share a converse correlation of expression in ovarian cancer cell lines and patient samples. We observed an increase in the expression levels of c-Myc with a concomitant decrease in the levels of FBXO31 in higher grades of ovarian cancer patient samples. In conclusion, our study demonstrated that oncogene c-Myc impairs the tumor-suppressive functions of FBXO31 to promote ovarian cancer progression, and therefore c-Myc-FBXO31 axis can be explored to develop better cancer therapy. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Sehbanul Islam
- National Centre for Cell Science, NCCS Complex, Ganeshkhind Road, Pune, Maharashtra, India.,Department of Biotechnology, Savitribai Phule Pune University, Pune, Maharashtra, India
| | - Parul Dutta
- National Centre for Cell Science, NCCS Complex, Ganeshkhind Road, Pune, Maharashtra, India.,Department of Biotechnology, Savitribai Phule Pune University, Pune, Maharashtra, India
| | - Osheen Sahay
- National Centre for Cell Science, NCCS Complex, Ganeshkhind Road, Pune, Maharashtra, India.,Department of Biotechnology, Savitribai Phule Pune University, Pune, Maharashtra, India
| | - K Gopalakrishnan
- National Centre for Cell Science, NCCS Complex, Ganeshkhind Road, Pune, Maharashtra, India
| | - Sushrita Roy Muhury
- National Centre for Cell Science, NCCS Complex, Ganeshkhind Road, Pune, Maharashtra, India
| | - Parinitha Parameshwar
- Department of Pathology, SDM College of Medical Sciences & Hospital, Sattur, Dharwad, India
| | - Praveenkumar Shetty
- K. S. Hegde Medical Academy, NITTE (Deemed to be University), University Enclave, Medical Sciences Complex, Dheralakatte, Mangalore, India
| | - Manas Kumar Santra
- National Centre for Cell Science, NCCS Complex, Ganeshkhind Road, Pune, Maharashtra, India
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5
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Zhu X, Xu T, Zhu J. The regulatory function of tandem repeat VNTR2-1 in hTERT gene involves basic Helix-loop-helix family transcription factors. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2021; 62:338-349. [PMID: 34115413 PMCID: PMC9648534 DOI: 10.1002/em.22447] [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: 04/14/2021] [Revised: 06/06/2021] [Accepted: 06/09/2021] [Indexed: 06/12/2023]
Abstract
Telomerase is a ribonucleoprotein enzyme that synthesizes telomere end sequence. The expression of hTERT gene, encoding the catalytic subunit of human telomerase, is restricted to highly proliferative tissues and is undetectable in most somatic cells. Abnormal activation of hTERT gene is found in 90% of human tumors. Previously, we identified tandem repeat of 42-bp/unit, VNTR2-1, in intron 2 of the hTERT gene, as a novel regulatory element important for hTERT transcription in cancer cells. In the current study, we found that multiple 42-bp repeats of VNTR2-1 activated luciferase gene in reporter plasmids. Mutation of the predicted cis-regulatory elements within the 42-bp repeats, including a E-box motif, resulted in a partial or complete loss of its enhancer activity. Moreover, MYC family proteins, c-MYC, MAX, and MNT, regulated hTERT gene transcription through both VNTR2-1 and E-boxes at the proximal hTERT promoter. Chromatin segmentation analysis of published ChIP-sequencing data from K562 cells indicated that VNTR2-1 was a bivalent enhancer. In telomerase-expressing human melanoma cell line MelJuSo, deletion of VNTR2-1 caused the hTERT promoter chromatin status to change from an active state to a repressed state, accompanied by increases of H3K27me3 and H3K9me3 marks. Therefore, we provided additional evidence for VNTR2-1 as a functional regulatory element that regulated hTERT expression by MYC family transcription factors. These results have improved our knowledge on the functions of repetitive genomic DNAs and the regulatory mechanisms of human telomerase gene.
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Affiliation(s)
| | | | - Jiyue Zhu
- To whom correspondence should be addressed. Tel: 1-509-368-6565; Fax: 1-509-368-6561; ; 412E Spokane Falls Blvd, PBS323, Spokane, WA, 99202, USA
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6
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Xu T, Cheng D, Zhao Y, Zhang J, Zhu X, Zhang F, Chen G, Wang Y, Yan X, Robertson GP, Gaddameedhi S, Lazarus P, Wang S, Zhu J. Polymorphic tandem DNA repeats activate the human telomerase reverse transcriptase gene. Proc Natl Acad Sci U S A 2021; 118:e2019043118. [PMID: 34155099 PMCID: PMC8256013 DOI: 10.1073/pnas.2019043118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Multiple independent sequence variants of the hTERT locus have been associated with telomere length and cancer risks in genome-wide association studies. Here, we identified an intronic variable number tandem repeat, VNTR2-1, as an enhancer-like element, which activated hTERT transcription in a cell in a chromatin-dependent manner. VNTR2-1, consisting of 42-bp repeats with an array of enhancer boxes, cooperated with the proximal promoter in the regulation of hTERT transcription by basic helix-loop-helix transcription factors and maintained hTERT expression during embryonic stem-cell differentiation. Genomic deletion of VNTR2-1 in MelJuSo melanoma cells markedly reduced hTERT transcription, leading to telomere shortening, cellular senescence, and impairment of xenograft tumor growth. Interestingly, VNTR2-1 lengths varied widely in human populations; hTERT alleles with shorter VNTR2-1 were underrepresented in African American centenarians, indicating its role in human aging. Therefore, this polymorphic element is likely a missing link in the telomerase regulatory network and a molecular basis for genetic diversities of telomere homeostasis and age-related disease susceptibilities.
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Affiliation(s)
- Tao Xu
- College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA 99210
- College of Life Science, Northeast Forestry University, Harbin 150040, China
| | - De Cheng
- College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA 99210
| | - Yuanjun Zhao
- Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, PA 17033
| | - Jinglong Zhang
- College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA 99210
| | - Xiaolu Zhu
- College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA 99210
| | - Fan Zhang
- College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA 99210
| | - Gang Chen
- College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA 99210
| | - Yang Wang
- College of Life Science, Northeast Forestry University, Harbin 150040, China
| | - Xiufeng Yan
- College of Life Science, Northeast Forestry University, Harbin 150040, China
- College of Life and Environmental Science, Wenzhou University, Chashan University Town, Wenzhou 325035, China
| | - Gavin P Robertson
- Department of Pharmacology, Pennsylvania State University College of Medicine, Hershey, PA 17033
- Department of Pathology, Pennsylvania State University College of Medicine, Hershey, PA 17033
- Department of Dermatology, Pennsylvania State University College of Medicine, Hershey, PA 17033
- Department of Surgery, Pennsylvania State University College of Medicine, Hershey, PA 17033
| | - Shobhan Gaddameedhi
- Center for Human Health and the Environment, Department of Biological Sciences, North Carolina State University, Raleigh, NC 27606
| | - Philip Lazarus
- College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA 99210
| | - Shuwen Wang
- College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA 99210
| | - Jiyue Zhu
- College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA 99210;
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7
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Zhang T, Ding H, Wang Y, Yuan Z, Zhang Y, Chen G, Xu Y, Chen L. Akt3-mTOR regulates hippocampal neurogenesis in adult mouse. J Neurochem 2021; 159:498-511. [PMID: 34077553 DOI: 10.1111/jnc.15441] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Revised: 04/16/2021] [Accepted: 05/26/2021] [Indexed: 01/19/2023]
Abstract
Akt signaling has been associated with adult neurogenesis in the hippocampal dentate gyrus (DG). We reported cognitive dysfunction in Akt3 knockout (Akt3-KO) mice with the down-regulation of mTOR activation. However, little is known about the effects of Akt3 signaling on hippocampal neurogenesis. Herein, we show that progenitor cells, neuroblasts, and mature newborn neurons in hippocampal DG expressed Akt3 protein. The Akt3 phosphorylation in hippocampal DG was increased after voluntary wheel running for 7 days in wild-type mice (running WT mice), but not in Akt3-KO mice (running Akt3-KO mice). Subsequently, we observed that the proliferation of progenitor cells was suppressed in Akt3-KO mice and the mTOR inhibitor rapamycin-treated mice, whereas enhanced in running WT mice rather than running Akt3-KO mice. Neurite growth of neuroblasts was impaired in Akt3-KO mice and rapamycin-treated mice. In contrast, neither differentiation of progenitor cells nor migrating of newly generated neurons was altered in Akt3-KO mice or running WT mice. The levels of p70S6K and 4EBP1 phosphorylation were declined in Akt3-KO mice and elevated in running WT mice depending on mTOR activation. Furthermore, telomerase activity, telomere length, and expression of telomerase reverse transcriptase (TERT) were decreased in Akt3-KO mice but increased in running WT mice rather than running Akt3-KO mice, which required the mTOR activation. The study provides in vivo evidence that Akt3-mTOR signaling plays an important role in the proliferation of progenitor cells and neurite growth through positive regulated TERT expression and activation of p70S6K and 4EBP1.
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Affiliation(s)
- Tingting Zhang
- Department of Physiology, Nanjing Medical University, Nanjing, China
| | - Hong Ding
- Department of Neurology, Nanjing Drum Tower Hospital Clinical College of Nanjing Medical University, Nanjing, China.,The Second Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Ya Wang
- Department of Physiology, Nanjing Medical University, Nanjing, China
| | - Zihao Yuan
- Department of Physiology, Nanjing Medical University, Nanjing, China
| | - Yajie Zhang
- Department of Physiology, Nanjing Medical University, Nanjing, China
| | - Guiquan Chen
- State Key Laboratory of Pharmaceutical Biotechnology, MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Nanjing, China
| | - Yun Xu
- Department of Neurology, Nanjing Drum Tower Hospital Clinical College of Nanjing Medical University, Nanjing, China
| | - Ling Chen
- Department of Physiology, Nanjing Medical University, Nanjing, China
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8
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Li S, Khan MH, Wang X, Cai M, Zhang J, Jiang M, Zhang Z, Wen XA, Liang H, Yang F. Synthesis of a series of novel In(III) 2,6-diacetylpyridine bis(thiosemicarbazide) complexes: structure, anticancer function and mechanism. Dalton Trans 2020; 49:17207-17220. [PMID: 33201167 DOI: 10.1039/d0dt02266g] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The anticancer function and anticancer mechanism of indium (In) complexes still remain mysterious to date. Furthermore, it is greatly challenging to design a multi-functional metal agent that not only kills cancer cells but also inhibits their invasion and metastasis. Thus, to develop novel next-generation anticancer metal agents, we designed and synthesized a series of novel In(iii) 2,6-diacetylpyridine bis(thiosemicarbazide) complexes (C1-C4) for the first time and then investigated their structure-activity relationships with human urinary bladder cancer (T-24) cells. In particular, C4 not only showed higher cytotoxicity to cancer cells and less toxicity toward normal cells relative to cisplatin but also inhibited cell invasion and metastasis of T-24 cells. Interestingly, C4 acted against T-24 cells exhibiting multiple mechanisms: (1) arresting the S-phase of cell cycle via regulation of cytokine kinases, (2) activating the mitochondrial-mediated apoptosis, endoplasmic reticulum-stress-mediated cell death, PERK and c-Jun N-terminal kinase 1 (JNK) cell signaling pathways, and (3) inhibiting the expression of telomerase via the regulation of c-myc and h-TERT proteins. Our results suggested that C4 may be developed as a potential multi-functional and multi-targeting anticancer candidate.
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Affiliation(s)
- Shanhe Li
- State Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources, Ministry of Science and Technology of China, Guangxi Normal University, Guilin, Guangxi, China.
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9
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Li W, Yan Y, Zheng Z, Zhu Q, Long Q, Sui S, Luo M, Chen M, Li Y, Hua Y, Deng W, Lai R, Li L. Targeting the NCOA3-SP1-TERT axis for tumor growth in hepatocellular carcinoma. Cell Death Dis 2020; 11:1011. [PMID: 33239622 PMCID: PMC7689448 DOI: 10.1038/s41419-020-03218-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Revised: 11/05/2020] [Accepted: 11/09/2020] [Indexed: 12/11/2022]
Abstract
Hepatocellular carcinoma (HCC) has a high mortality rate and lacks an effective therapeutic target. Elevated expression of human telomerase reverse transcriptase (TERT) is an important hallmark in cancers, but the mechanism by which TERT is activated differentially in cancers is poorly understood. Here, we have identified nuclear receptor coactivator-3 (NCOA3) as a new modulator of TERT expression and tumor growth in HCC. NACO3 specifically binds to the TERT promoter at the -234 to -144 region and transcriptionally activates TERT expression. NCOA3 promotes HCC cell growth and tumor progression in vitro and in vivo through upregulating the TERT signaling. Knockdown of NACO3 suppresses HCC cell viability and colony formation, whereas TERT overexpression rescues this suppression. NCOA3 interacts with and recruits SP1 binding on the TERT promoter. Knockdown of NCOA3 also inhibits the expression of the Wnt signaling-related genes but has no effect on the Notch signaling-targeting genes. Moreover, NCOA3 is positively correlated with TERT expression in HCC tumor tissues, and high expression of both NCOA3 and TERT predicts a poor prognosis in HCC patients. Our findings indicate that targeting the NCOA3-SP1-TERT signaling axis may benefit HCC patients.
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Affiliation(s)
- Wenbin Li
- Sun Yat-sen University Cancer Center; State Key Laboratory of Oncology in South China; Collaborative Innovation Center of Cancer Medicine, Guangzhou, China.,Institute of Neuroscience and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - Yue Yan
- Sun Yat-sen University Cancer Center; State Key Laboratory of Oncology in South China; Collaborative Innovation Center of Cancer Medicine, Guangzhou, China
| | - Zongheng Zheng
- The Third Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Qiaohua Zhu
- Shunde Hospital of Southern Medical University, Foshan, Guangdong, China
| | - Qian Long
- Sun Yat-sen University Cancer Center; State Key Laboratory of Oncology in South China; Collaborative Innovation Center of Cancer Medicine, Guangzhou, China
| | - Silei Sui
- Institute of Cancer Stem Cell, Dalian Medical University, Dalian, China
| | - Meihua Luo
- Shunde Hospital of Southern Medical University, Foshan, Guangdong, China
| | - Miao Chen
- Sun Yat-sen University Cancer Center; State Key Laboratory of Oncology in South China; Collaborative Innovation Center of Cancer Medicine, Guangzhou, China
| | - Yizhuo Li
- Sun Yat-sen University Cancer Center; State Key Laboratory of Oncology in South China; Collaborative Innovation Center of Cancer Medicine, Guangzhou, China
| | - Yijun Hua
- Sun Yat-sen University Cancer Center; State Key Laboratory of Oncology in South China; Collaborative Innovation Center of Cancer Medicine, Guangzhou, China
| | - Wuguo Deng
- Sun Yat-sen University Cancer Center; State Key Laboratory of Oncology in South China; Collaborative Innovation Center of Cancer Medicine, Guangzhou, China.
| | - Renchun Lai
- Sun Yat-sen University Cancer Center; State Key Laboratory of Oncology in South China; Collaborative Innovation Center of Cancer Medicine, Guangzhou, China.
| | - Liren Li
- Sun Yat-sen University Cancer Center; State Key Laboratory of Oncology in South China; Collaborative Innovation Center of Cancer Medicine, Guangzhou, China.
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10
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Epigenetic modifications of c-MYC: Role in cancer cell reprogramming, progression and chemoresistance. Semin Cancer Biol 2020; 83:166-176. [PMID: 33220458 DOI: 10.1016/j.semcancer.2020.11.008] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Revised: 11/05/2020] [Accepted: 11/08/2020] [Indexed: 12/12/2022]
Abstract
Both genetic and epigenetic mechanisms intimately regulate cancer development and chemoresistance. Different genetic alterations are observed in multiple genes, and most are irreversible. Aside from genetic alterations, epigenetic alterations play a crucial role in cancer. The reversible nature of epigenetic modifications makes them an attractive target for cancer prevention and therapy. Specific epigenetic alteration is also being investigated as a potential biomarker in multiple cancers. c-MYC is one of the most important transcription factors that are centrally implicated in multiple types of cancer cells reprogramming, proliferation, and chemoresistance. c-MYC shows not only genetic alterations but epigenetic changes in multiple cancers. It has been observed that epigenome aberrations can reversibly alter the expression of c-MYC, both transcriptional and translational levels. Understanding the underlying mechanism of the epigenetic alterations of c-MYC, that has its role in multiple levels of cancer pathogenesis, can give a better understanding of various unresolved questions regarding cancer. Recently, some researchers reported that targeting the epigenetic modifiers of c-MYC can successfully inhibit cancer cell proliferation, sensitize the chemoresistant cells, and increase the patient survival rate. As c-MYC is an important transcription factor, epigenetic therapy might be one of the best alternatives for the conventional therapies that assumes the "one-size-fits-all" role. It can also increase the precision of targeting and enhance the effectiveness of treatments among various cancer subtypes. In this review, we highlighted the role of epigenetically modified c-MYC in cancer cell reprogramming, progression, and chemoresistance. We also summarize the potential therapeutic approaches to target these modifications for the prevention of cancer development and chemoresistant phenotypes.
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11
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Rosen J, Jakobs P, Ale-Agha N, Altschmied J, Haendeler J. Non-canonical functions of Telomerase Reverse Transcriptase - Impact on redox homeostasis. Redox Biol 2020; 34:101543. [PMID: 32502898 PMCID: PMC7267725 DOI: 10.1016/j.redox.2020.101543] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 04/11/2020] [Accepted: 04/13/2020] [Indexed: 02/08/2023] Open
Abstract
Telomerase consists of the catalytic subunit Telomerase Reverse Transcriptase (TERT) and the Telomerase RNA Component. Its canonical function is the prevention of telomere erosion. Over the last years it became evident that TERT is also present in tissues with low replicative potential. Important non-canonical functions of TERT are protection against apoptosis and maintenance of the cellular redox homeostasis in cancer as well as in somatic tissues. Intriguingly, TERT and reactive oxygen species (ROS) are interdependent on each other, with TERT being regulated by changes in the redox balance and itself controlling ROS levels in the cytosol and in the mitochondria. The latter is achieved because TERT is present in the mitochondria, where it protects mitochondrial DNA and maintains levels of anti-oxidative enzymes. Since numerous diseases are associated with oxidative stress, increasing the mitochondrial TERT level could be of therapeutic value.
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Affiliation(s)
- Julia Rosen
- Environmentally-induced Cardiovascular Degeneration, Institute of Clinical Chemistry and Laboratory Diagnostics, Medical Faculty, Heinrich-Heine University Düsseldorf, Germany; IUF-Leibniz Research Institute for Environmental Medicine, Düsseldorf, Germany
| | - Philipp Jakobs
- Environmentally-induced Cardiovascular Degeneration, Institute of Clinical Chemistry and Laboratory Diagnostics, Medical Faculty, Heinrich-Heine University Düsseldorf, Germany; IUF-Leibniz Research Institute for Environmental Medicine, Düsseldorf, Germany
| | - Niloofar Ale-Agha
- Environmentally-induced Cardiovascular Degeneration, Institute of Clinical Chemistry and Laboratory Diagnostics, Medical Faculty, Heinrich-Heine University Düsseldorf, Germany; IUF-Leibniz Research Institute for Environmental Medicine, Düsseldorf, Germany
| | - Joachim Altschmied
- IUF-Leibniz Research Institute for Environmental Medicine, Düsseldorf, Germany.
| | - Judith Haendeler
- Environmentally-induced Cardiovascular Degeneration, Institute of Clinical Chemistry and Laboratory Diagnostics, Medical Faculty, Heinrich-Heine University Düsseldorf, Germany; IUF-Leibniz Research Institute for Environmental Medicine, Düsseldorf, Germany.
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12
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Zhang F, Cheng D, Wang S, Zhu J. Crispr/Cas9-mediated cleavages facilitate homologous recombination during genetic engineering of a large chromosomal region. Biotechnol Bioeng 2020; 117:2816-2826. [PMID: 32449788 DOI: 10.1002/bit.27441] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 04/26/2020] [Accepted: 05/18/2020] [Indexed: 02/06/2023]
Abstract
Homologous recombination over large genomic regions is difficult to achieve due to low efficiencies. Here, we report the successful engineering of a humanized mTert allele, hmTert, in the mouse genome by replacing an 18.1-kb genomic region around the mTert gene with a recombinant fragment of over 45.5 kb, using homologous recombination facilitated by the Crispr/Cas9 technology, in mouse embryonic stem cells (mESCs). In our experiments, with DNA double-strand breaks (DSBs) generated by Crispr/Cas9 system, the homologous recombination efficiency was up to 11% and 16% in two mESC lines TC1 and v6.5, respectively. Overall, we obtained a total of 27 mESC clones with heterozygous hmTert/mTert alleles and three clones with homozygous hmTert alleles. DSBs induced by Crispr/Cas9 cleavages also caused high rates of genomic DNA deletions and mutations at single-guide RNA target sites. Our results indicated that the Crispr/Cas9 system significantly increased the efficiency of homologous recombination-mediated gene editing over a large genomic region in mammalian cells, and also caused frequent mutations at unedited target sites. Overall, this strategy provides an efficient and feasible way for manipulating large chromosomal regions.
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Affiliation(s)
- Fan Zhang
- Department of Pharmaceutical Sciences, Washington State University College of Pharmacy, Spokane, Washington
| | - De Cheng
- Department of Pharmaceutical Sciences, Washington State University College of Pharmacy, Spokane, Washington
| | - Shuwen Wang
- Department of Pharmaceutical Sciences, Washington State University College of Pharmacy, Spokane, Washington
| | - Jiyue Zhu
- Department of Pharmaceutical Sciences, Washington State University College of Pharmacy, Spokane, Washington
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Zhang F, Wang S, Zhu J. ETS variant transcription factor 5 and c-Myc cooperate in derepressing the human telomerase gene promoter via composite ETS/E-box motifs. J Biol Chem 2020; 295:10062-10075. [PMID: 32518154 DOI: 10.1074/jbc.ra119.012130] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Revised: 06/04/2020] [Indexed: 12/19/2022] Open
Abstract
The human telomerase gene (hTERT) is repressed in most somatic cells. How transcription factors activate the hTERT promoter in its repressive chromatin environment is unknown. Here, we report that the ETS family protein ETS variant transcription factor 5 (ETV5) mediates epidermal growth factor (EGF)-induced hTERT expression in MCF10A cells. This activation required MYC proto-oncogene bHLH transcription factor (c-Myc) and depended on the chromatin state of the hTERT promoter. Using chromatinized bacterial artificial chromosome (BAC) reporters in human fibroblasts, we found that ETV5 and c-Myc/MYC-associated factor X (MAX) synergistically activate the hTERT promoter via two identical, but inverted, composite Ets/E-box motifs enclosing the core promoter. Mutations of Ets or E-box sites in either DNA motif abolished the activation and reduced or eliminated the synergism. ETV5 and c-Myc facilitated each other's binding to the hTERT promoter. ETV5 bound to the hTERT promoter in both telomerase-negative and -positive cells, but it activated the repressed hTERT promoter and altered histone modifications only in telomerase-negative cells. The synergistic ETV5/c-Myc activation disappeared when hTERT promoter repression became relieved because of the loss of distal regulatory elements in chimeric human/mouse BAC reporters. Our results suggest that the binding of c-Myc and ETS family proteins to the Ets/E-box motifs derepresses the hTERT promoter by inducing an active promoter configuration, providing a mechanistic insight into hTERT activation during tumorigenesis.
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Affiliation(s)
- Fan Zhang
- Department of Pharmaceutical Sciences, Washington State University College of Pharmacy and Pharmaceutical Sciences, Spokane, Washington, USA
| | - Shuwen Wang
- Department of Pharmaceutical Sciences, Washington State University College of Pharmacy and Pharmaceutical Sciences, Spokane, Washington, USA
| | - Jiyue Zhu
- Department of Pharmaceutical Sciences, Washington State University College of Pharmacy and Pharmaceutical Sciences, Spokane, Washington, USA
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Qin QP, Wang ZF, Huang XL, Tan MX, Luo ZH, Wang SL, Zou BQ, Liang H. Two telomerase-targeting Pt(ii) complexes of jatrorrhizine and berberine derivatives induce apoptosis in human bladder tumor cells. Dalton Trans 2020; 48:15247-15254. [PMID: 31577283 DOI: 10.1039/c9dt02381j] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Two novel Pt(ii) complexes, [Pt(B-TFA)Cl]Cl (Pt1) and [Pt(J-TFA)Cl]Cl (Pt2) with jatrorrhizine and berberine derivatives (B-TFA and J-TFA) were first prepared as desirable luminescent agents for cellular applications and potent telomerase inhibitors, which can induce bladder T-24 tumor cell apoptosis by targeting telomerase, together with induction of mitochondrial dysfunction, telomere DNA damage and cell-cycle arrest. Importantly, T-24 tumor inhibition rate (TIR) was 50.4% for Pt2, which was higher than that of Pt1 (26.4%) and cisplatin (37.1%). Taken together, all the results indicated that jatrorrhizine and berberine derivatives Pt1 and Pt2 show low toxicity and could be novel Pt-based anti-cancer drug candidates.
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Affiliation(s)
- Qi-Pin Qin
- Guangxi Key Lab of Agricultural Resources Chemistry and Biotechnology, College of Chemistry and Food Science, Yulin Normal University, 1303 Jiaoyudong Road, Yulin 537000, PR China.
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15
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McKelvey BA, Umbricht CB, Zeiger MA. Telomerase Reverse Transcriptase (TERT) Regulation in Thyroid Cancer: A Review. Front Endocrinol (Lausanne) 2020; 11:485. [PMID: 32849278 PMCID: PMC7412884 DOI: 10.3389/fendo.2020.00485] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 06/22/2020] [Indexed: 12/17/2022] Open
Abstract
Telomerase reverse transcriptase (TERT) is the catalytic subunit of the enzyme telomerase and is essential for telomerase activity. Upregulation of TERT expression and resulting telomerase activity occurs in the large majority of malignancies, including thyroid cancer. This upregulation results in continued cellular proliferation and avoidance of cellular senescence and cell death. In this review we will briefly introduce TERT and telomerase activity as it pertains to thyroid cancer and, highlight the effects of TERT on cancer cells. We will also explore in detail the different TERT regulatory strategies and how TERT is reactivated in thyroid cancer cells, specifically. These regulatory mechanisms include both activating single base pair TERT promoter mutations and epigenetic changes at the promoter, including changes in CpG methylation and histone modifications that affect chromatin structure. Further, regulation includes the allele-specific regulation of the TERT promoter in thyroid cancer cells harboring the TERT promoter mutation. These entail allele-specific transcriptional activator binding, DNA methylation, histone modifications, and mono-allelic expression of TERT. Lastly, TERT copy number alterations and alternative splicing are also implicated. Both amplifications of the TERT locus and increased full-length transcripts and decreased inactive and dominant negative isoforms result in active telomerase. Finally, the clinical significance of TERT in thyroid cancer is also reviewed.
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Affiliation(s)
- Brittany A. McKelvey
- Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Christopher B. Umbricht
- Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Martha A. Zeiger
- Surgical Oncology Program, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States
- *Correspondence: Martha A. Zeiger
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Avin BA, Wang Y, Gilpatrick T, Workman RE, Lee I, Timp W, Umbricht CB, Zeiger MA. Characterization of human telomerase reverse transcriptase promoter methylation and transcription factor binding in differentiated thyroid cancer cell lines. Genes Chromosomes Cancer 2019; 58:530-540. [PMID: 30664813 PMCID: PMC6621557 DOI: 10.1002/gcc.22735] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 01/04/2019] [Accepted: 01/14/2019] [Indexed: 12/27/2022] Open
Abstract
Telomerase reverse transcriptase (TERT) activation plays an important role in cancer development by enabling the immortalization of cells. TERT regulation is multifaceted, and its promoter methylation has been implicated in controlling expression through alteration in transcription factor binding. We have characterized TERT promoter methylation, transcription factor binding, and TERT expression levels in five differentiated thyroid cancer (DTC) cell lines and six normal thyroid tissue samples by targeted bisulfite sequencing, ChIP-qPCR, and qRT-PCR. DTC cell lines express varying levels of TERT and exhibit TERT promoter methylation patterns similar to patterns seen in other telomerase positive cancer cell lines. The minimal promoter immediately surrounding the transcription start site is hypomethylated, while further upstream portions show dense methylation. In contrast, the TERT promoter in normal thyroid tissue is largely unmethylated throughout and expresses TERT minimally. Transcription factor binding is also affected by TERT mutation status. The E-twenty-six (ETS) factor GABPA exhibits TERT binding in the TERT mutant DTC cells only, and allele-specific methylation patterns at the minimal promoter were observed as well, which may indicate allele-specific factor recruitment at the minimal promoter. Furthermore, we identified binding sites for activators MYC and GSC in the hypermethylated upstream region, pointing to its possible importance in TERT regulation. Overall, TERT expression and telomerase activity depend on the interplay of multiple regulatory mechanisms including TERT promoter methylation, mutation status, and recruitment of transcription factors. This work explores of the interplay between these regulatory mechanisms and offers insight into cellular control of active telomerase in human cancer.
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Affiliation(s)
- Brittany A. Avin
- Department of Surgery, Johns Hopkins University, Baltimore, MD, United States 21287
- Department of Molecular Biology and Genetics, Johns Hopkins University, Baltimore, MD, United States 21287
| | - Yongchun Wang
- Department of Surgery, Johns Hopkins University, Baltimore, MD, United States 21287
| | - Timothy Gilpatrick
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, United States 21287
| | - Rachael E. Workman
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, United States 21287
| | - Isac Lee
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, United States 21287
| | - Winston Timp
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, United States 21287
| | - Christopher B. Umbricht
- Department of Surgery, Johns Hopkins University, Baltimore, MD, United States 21287
- Department of Oncology, Johns Hopkins University, Baltimore, MD, United States 21287
- Department of Pathology, Johns Hopkins University, Baltimore, MD, United States 21287
| | - Martha A. Zeiger
- Department of Surgery, The University of Virginia School of Medicine, Charlottesville, VA 22908
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Schořová Š, Fajkus J, Záveská Drábková L, Honys D, Schrumpfová PP. The plant Pontin and Reptin homologues, RuvBL1 and RuvBL2a, colocalize with TERT and TRB proteins in vivo, and participate in telomerase biogenesis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 98:195-212. [PMID: 30834599 DOI: 10.1111/tpj.14306] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 02/08/2019] [Accepted: 02/26/2019] [Indexed: 05/15/2023]
Abstract
Telomerase maturation and recruitment to telomeres is regulated by several telomerase- and telomere-associated proteins. Among a number of proteins, human Pontin and Reptin play critical roles in telomerase biogenesis. Here we characterized plant orthologues of Pontin and Reptin, RuvBL1 and RuvBL2a, respectively, and show association of Arabidopsis thaliana RuvBL1 (AtRuvBL1) with the catalytic subunit of telomerase (AtTERT) in the nucleolus in vivo. In contrast to mammals, interactions between AtTERT and AtRuvBL proteins in A. thaliana are not direct and they are rather mediated by one of the Arabidopsis thaliana Telomere Repeat Binding (AtTRB) proteins. We further show that plant orthologue of dyskerin, named AtCBF5, is indirectly associated with AtTRB proteins but not with the AtRuvBL proteins in the plant nucleus/nucleolus, and interacts with the Protection of telomere 1 (AtPOT1a) in the nucleolus or cytoplasmic foci. Our genome-wide phylogenetic analyses identify orthologues in RuvBL protein family within the plant kingdom. Dysfunction of AtRuvBL genes in heterozygous T-DNA insertion A. thaliana mutants results in reduced telomerase activity and indicate the involvement of AtRuvBL in plant telomerase biogenesis.
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Affiliation(s)
- Šárka Schořová
- Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Jiří Fajkus
- Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno, Czech Republic
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Brno, Czech Republic
- Institute of Biophysics of the Czech Academy of Sciences, v.v.i., Brno, Czech Republic
| | - Lenka Záveská Drábková
- Laboratory of Pollen Biology, Institute of Experimental Botany of the Czech Academy of Sciences, v.v.i., Prague, Czech Republic
| | - David Honys
- Laboratory of Pollen Biology, Institute of Experimental Botany of the Czech Academy of Sciences, v.v.i., Prague, Czech Republic
| | - Petra Procházková Schrumpfová
- Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno, Czech Republic
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Dilshara MG, Jayasooriya RGPT, Choi YH, Kim GY. Camptothecin induces c-Myc- and Sp1-mediated hTERT expression in LNCaP cells: Involvement of reactive oxygen species and PI3K/Akt. Food Chem Toxicol 2019; 127:53-60. [PMID: 30851366 DOI: 10.1016/j.fct.2019.03.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2018] [Revised: 02/14/2019] [Accepted: 03/01/2019] [Indexed: 01/08/2023]
Abstract
Camptothecin (CPT), a quinoline alkaloid isolated from Camptotheca acuminate, targets topoisomerase I, which is continuously expressed in cancer cells. However, the molecular mechanisms responsible for CPT-induced telomerase inhibition remain unclear. Unexpectedly, we found that CPT upregulates hTERT expression and concomitantly increases telomerase activity. However, transfection of hTERT-targeting siRNA had no effect on CPT-induced G2/M phase arrest, suggesting that CPT-induced telomerase activation was not related to G2/M phase arrest. CPT simultaneously increased Nrf2 expression and the level of intracellular reactive oxygen species (ROS), whereas pretreatment with the antioxidants N-acetyl-cysteine (NAC) or glutathione (GSH) strongly attenuated ROS production, which was accompanied by hTERT downregulation. Additionally, transient Nrf2 knockdown enhanced CPT-induced ROS production and hTERT promoter activity. CPT also upregulated hTERT expression and telomerase activity by inducing c-Myc and Sp1 expression and activity. Moreover, c-Myc stimulated ROS production in response to CPT, leading to Sp1 activation, which promoted hTERT expression and telomerase activity. CPT treatment enhanced the phosphorylation of PI3K and Akt, which led to hTERT phosphorylation into the nucleus. These findings demonstrate that CPT positively regulates telomerase activity by upregulating hTERT expression and phosphorylation via the c-Myc/ROS/Sp1 and PI3K/Akt axis.
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Affiliation(s)
| | | | - Yung Hyun Choi
- Department of Biochemistry, College of Oriental Medicine, Dong-Eui University, Busan 47227, Republic of Korea
| | - Gi-Young Kim
- Department of Marine Life Sciences, Jeju National University, Jeju 63243, Republic of Korea.
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Li Y, Xiang C, Shen N, Deng L, Luo X, Yuan P, Ji Z, Li J, Cheng L. Functional polymorphisms on chromosome 5p15.33 disturb telomere biology and confer the risk of non‐small cell lung cancer in Chinese population. Mol Carcinog 2019; 58:913-921. [DOI: 10.1002/mc.22980] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 01/10/2019] [Accepted: 01/18/2019] [Indexed: 12/15/2022]
Affiliation(s)
- Ying Li
- Department of Laboratory MedicineTongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Cheng Xiang
- Department of Laboratory MedicineTongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Na Shen
- Department of Laboratory MedicineTongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Lingyan Deng
- Department of Laboratory MedicineTongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Xia Luo
- Department of Laboratory MedicineTongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Peihong Yuan
- Department of Laboratory MedicineTongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Zhi Ji
- Department of Laboratory MedicineTongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Jiaoyuan Li
- Department of Laboratory MedicineTongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Liming Cheng
- Department of Laboratory MedicineTongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
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Shin PK, Zoh Y, Choi J, Kim MS, Kim Y, Choi SW. Walnut phenolic extracts reduce telomere length and telomerase activity in a colon cancer stem cell model. Nutr Res Pract 2019; 13:58-63. [PMID: 30788057 PMCID: PMC6369112 DOI: 10.4162/nrp.2019.13.1.58] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 03/28/2018] [Accepted: 09/19/2018] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND/OBJECTIVES Telomeres are located at the chromosomal ends and progressively shortened during each cell cycle. Telomerase, which is regulated by hTERT and c-MYC, maintains telomeric DNA sequences. Especially, telomerase is active in cancer and stem cells to maintain telomere length for replicative immortality. Recently we reported that walnut phenolic extract (WPE) can reduce cell viability in a colon cancer stem cell (CSC) model. We, therefore, investigated the effect of WPE on telomere maintenance in the same model. MATERIALS/METHODS CD133+CD44+ cells from HCT116, a human colon cancer cell line, were sorted by Fluorescence-activated cell sorting (FACS) and treated with WPE at the concentrations of 0, 10, 20, and 40 µg/mL for 6 days. Telomere lengths were assessed by quantitative real-time PCR (qRT-PCR) using telomere specific primers and DNA extracted from the cells, which was further adjusted with single-copy gene and reference DNA (ddCt). Telomerase activity was also measured by qRT-PCR after incubating the PCR mixture with cell protein extracts, which was adjusted with reference DNA (dCt). Transcriptions of hTERT and c-MYC were determined using conventional RT-PCR. RESULTS Telomere length of WPE-treated cells was significantly decreased in a dose-dependent manner (5.16 ± 0.13 at 0 µg/mL, 4.79 ± 0.12 at 10 µg/mL, 3.24 ± 0.08 at 20 µg/mL and 3.99 ± 0.09 at 40 µg/mL; P = 0.0276). Telomerase activities concurrently decreased with telomere length (1.47 ± 0.04, 1.09 ± 0.01, 0.76 ± 0.08, and 0.88 ± 0.06; P = 0.0067). There was a positive correlation between telomere length and telomerase activity (r = 0.9090; P < 0.0001). Transcriptions of both hTERT and c-MYC were also significantly decreased in the same manner. CONCLUSION In the present cell culture model, WPE reduced telomere maintenance, which may provide a mechanistic link to the effect of walnuts on the viability of colon CSCs.
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Affiliation(s)
- Phil-Kyung Shin
- CHA University School of Medicine, 120, Haeryong-ro, Pocheon-si, Gyeonggi 13488, Korea
| | - Yoonchae Zoh
- CHA University School of Medicine, 120, Haeryong-ro, Pocheon-si, Gyeonggi 13488, Korea
| | - Jina Choi
- CHA University School of Medicine, 120, Haeryong-ro, Pocheon-si, Gyeonggi 13488, Korea
| | - Myung-Sunny Kim
- Division of Nutrition and Metabolism, Korea Food Research Institute, Jeonju, Jeonbuk 55365, Korea
| | - Yuri Kim
- Department of Nutritional Science and Food Management, Ewha Womans University, Seoul, 03760, Korea
| | - Sang-Woon Choi
- CHA University School of Medicine, 120, Haeryong-ro, Pocheon-si, Gyeonggi 13488, Korea
- Chaum Life Center CHA University, 442, Dosan-daero, Gangnam-gu, Seoul, 06062, Korea
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Qin QP, Meng T, Tan MX, Liu YC, Wang SL, Zou BQ, Liang H. Synthesis, characterization and biological evaluation of six highly cytotoxic ruthenium(ii) complexes with 4'-substituted-2,2':6',2''-terpyridine. MEDCHEMCOMM 2018; 9:525-533. [PMID: 30108943 PMCID: PMC6072480 DOI: 10.1039/c7md00532f] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 01/31/2018] [Indexed: 12/23/2022]
Abstract
Herein, six ruthenium(ii) terpyridine complexes, i.e. [RuCl2(4-EtN-Phtpy)(DMSO)] (Ru1), [RuCl2(4-MeO-Phtpy)(DMSO)] (Ru2), [RuCl2(2-MeO-Phtpy)(DMSO)] (Ru3), [RuCl2(3-MeO-Phtpy)(DMSO)] (Ru4), [RuCl2(1-Bip-Phtpy)(DMSO)] (Ru5), and [RuCl2(1-Pyr-Phtpy)(DMSO)] (Ru6) with 4'-(4-diethylaminophenyl)-2,2':6',2''-terpyridine (4-EtN-Phtpy), 4'-(4-methoxyphenyl)-2,2':6',2''-terpyridine (4-MeO-Phtpy), 4'-(2-methoxyphenyl)-2,2':6',2''-terpyridine (2-MeO-Phtpy), 4'-(3-methoxyphenyl)-2,2':6',2''-terpyridine (3-MeO-Phtpy), 4'-(1-biphenylene)-2,2':6',2''-terpyridine (1-Bip-Phtpy), and 4'-(1-pyrene)-2,2':6',2''-terpyridine (1-Pyr-Phtpy), respectively, were synthesized and fully characterized. The MTT assay demonstrates that the in vitro anticancer activity of Ru1 is higher than that of Ru2-Ru6 and more selective for Hep-G2 cells than for normal HL-7702 cells. In addition, various biological assays show that Ru1 and Ru6, especially the Ru1 complex, are telomerase inhibitors targeting c-myc G4 DNA and also cause apoptosis of Hep-G2 cells. With the same Ru center, the in vitro antitumor activity and cellular uptake ability of the 4-EtN-Phtpy and 1-Bip-Phtpy ligands follow the order 4-EtN-Phtpy > 1-Bip-Phtpy.
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Affiliation(s)
- Qi-Pin Qin
- Guangxi Key Laboratory of Agricultural Resources Chemistry and Biotechnology , College of Chemistry and Food Science , Yulin Normal University , 1303 Jiaoyudong Road , Yulin 537000 , PR China . ; ; ; Tel: +86 775 2623650
- State Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources , School of Chemistry and Pharmacy , Guangxi Normal University , 15 Yucai Road , Guilin 541004 , PR China
| | - Ting Meng
- Guangxi Key Laboratory of Agricultural Resources Chemistry and Biotechnology , College of Chemistry and Food Science , Yulin Normal University , 1303 Jiaoyudong Road , Yulin 537000 , PR China . ; ; ; Tel: +86 775 2623650
- State Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources , School of Chemistry and Pharmacy , Guangxi Normal University , 15 Yucai Road , Guilin 541004 , PR China
| | - Ming-Xiong Tan
- Guangxi Key Laboratory of Agricultural Resources Chemistry and Biotechnology , College of Chemistry and Food Science , Yulin Normal University , 1303 Jiaoyudong Road , Yulin 537000 , PR China . ; ; ; Tel: +86 775 2623650
- State Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources , School of Chemistry and Pharmacy , Guangxi Normal University , 15 Yucai Road , Guilin 541004 , PR China
| | - Yan-Cheng Liu
- State Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources , School of Chemistry and Pharmacy , Guangxi Normal University , 15 Yucai Road , Guilin 541004 , PR China
| | - Shu-Long Wang
- Guangxi Key Laboratory of Agricultural Resources Chemistry and Biotechnology , College of Chemistry and Food Science , Yulin Normal University , 1303 Jiaoyudong Road , Yulin 537000 , PR China . ; ; ; Tel: +86 775 2623650
- State Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources , School of Chemistry and Pharmacy , Guangxi Normal University , 15 Yucai Road , Guilin 541004 , PR China
| | - Bi-Qun Zou
- Department of Chemistry , Guilin Normal College , 21 Xinyi Road , Gulin 541001 , PR China .
| | - Hong Liang
- State Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources , School of Chemistry and Pharmacy , Guangxi Normal University , 15 Yucai Road , Guilin 541004 , PR China
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22
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Daniel M, Tollefsbol TO. Pterostilbene down-regulates hTERT at physiological concentrations in breast cancer cells: Potentially through the inhibition of cMyc. J Cell Biochem 2017; 119:3326-3337. [PMID: 29125889 DOI: 10.1002/jcb.26495] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 11/09/2017] [Indexed: 12/21/2022]
Abstract
Human telomerase reverse transcriptase (hTERT) encodes the catalytic subunit of telomerase, which has been shown to be upregulated in many cancers. Pterostilbene is a naturally occurring stilbenoid and phytoalexin found primarily in blueberries that exhibits antioxidant activity and inhibits the growth of various cancer cell types. Therefore, the aim of this study was to determine whether treatment with pterostilbene, at physiologically achievable concentrations, can inhibit the proliferation of breast cancer cells and down-regulate the expression of hTERT. We found that pterostilbene inhibits the cellular proliferation of MCF-7 and MDA-MB-231 breast cancer cells in both a time- and dose-dependent manner, without significant toxicity to the MCF10A control cells. Pterostilbene was also shown to increase apoptosis in both breast cancer cell lines. Dose-dependent cell cycle arrest in G1 and G2/M phase was observed after treatment with pterostilbene in MCF-7 and MDA-231 cells, respectively. hTERT expression was down-regulated after treatment in both a time- and dose-dependent manner. Pterostilbene also reduced telomerase levels in both cell lines in a dose-dependent manner. Moreover, cMyc, a proposed target of the pterostilbene-mediated inhibition of hTERT, was down-regulated both transcriptionally and posttranscriptionally after treatment. Collectively, these findings highlight a promising use of pterostilbene as a natural, preventive, and therapeutic agent against the development and progression of breast cancer.
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Affiliation(s)
- Michael Daniel
- Department of Biology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Trygve O Tollefsbol
- Department of Biology, University of Alabama at Birmingham, Birmingham, Alabama.,Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, Alabama.,Comprehensive Center for Healthy Aging, University of Alabama at Birmingham, Birmingham, Alabama.,Nutrition Obesity Research Center, University of Alabama at Birmingham, Birmingham, Alabama.,Comprehensive Diabetes Center, University of Alabama at Birmingham, Birmingham, Alabama
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23
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He X, Du S, Lei T, Li X, Liu Y, Wang H, Tong R, Wang Y. PKM2 in carcinogenesis and oncotherapy. Oncotarget 2017; 8:110656-110670. [PMID: 29299177 PMCID: PMC5746412 DOI: 10.18632/oncotarget.22529] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Accepted: 10/28/2017] [Indexed: 12/11/2022] Open
Abstract
Tumor cell metabolism is characterized by abundant glucose consumption and aerobic glycolysis. And pyruvate kinase M2 (PKM2) plays a decisive role in glycolysis, significantly contributing to the Warburg effect, tumor growth, angiogenesis, cell division, metastasis and apoptosis. To date, researchers have unraveled the potential of pyruvate kinase M2 as an antitumor target, which suggests a new orientation for oncotherapy. Herein, we focus on the role of pyruvate kinase M2 in tumor cell development and its function as a potential new therapeutic target for tumor treatment. Besides, research actuality on pyruvate kinase M2-dependent glycometabolism and signaling pathway in tumors is also summarized, providing valuable suggestions for further study in this field.
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Affiliation(s)
- Xia He
- Department of Pharmacy, Sichuan Academy of Medical Science & Sichuan Provincial People's Hospital, Chengdu, Sichuan 610072, China
| | - Suya Du
- School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan 610054, China
| | - Tiantian Lei
- School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan 610054, China
| | - Xiang Li
- School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan 610054, China
| | - Yilong Liu
- Department of Pharmacy, The People's Hospital of Leshan, Leshan, Sichuan 614000, China
| | - Hailian Wang
- Institute of Organ Transplantation, Sichuan Academy of Medical Science & Sichuan Provincial People's Hospital, Chengdu, Sichuan 610072, China
| | - Rongsheng Tong
- Department of Pharmacy, Sichuan Academy of Medical Science & Sichuan Provincial People's Hospital, Chengdu, Sichuan 610072, China
| | - Yi Wang
- Department of Pharmacy, Sichuan Academy of Medical Science & Sichuan Provincial People's Hospital, Chengdu, Sichuan 610072, China
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24
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Regulation of human and mouse telomerase genes by genomic contexts and transcription factors during embryonic stem cell differentiation. Sci Rep 2017; 7:16444. [PMID: 29180668 PMCID: PMC5703907 DOI: 10.1038/s41598-017-16764-w] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 11/16/2017] [Indexed: 12/14/2022] Open
Abstract
Differential regulation of telomerase reverse transcriptase (TERT) genes contribute to distinct aging and tumorigenic processes in humans and mice. To study TERT regulation, we generated mouse embryonic stem cell (ESC) lines containing single-copy bacterial artificial chromosome (BAC) reporters, covering hTERT and mTERT genes and their neighboring loci, via recombinase-mediated BAC targeting. ESC lines with chimeric BACs, in which two TERT promoters were swapped, were also generated. Using these chromatinized BACs, we showed that hTERT silencing during differentiation to embryoid bodies (EBs) and to fibroblast-like cells was driven by the human-specific genomic context and accompanied by increases of repressive epigenetic marks, H3K9me3 and H3K27me3, near its promoter. Conversely, the mouse genomic context did not repress TERT transcription until late during differentiation. The hTERT promoter was more active than its mouse counterpart when compared in the same genomic contexts. Mutations of E-box and E2F consensus sites at the promoter had little effect on hTERT transcription in ESCs. However, the mutant promoters were rapidly silenced upon EB differentiation, indicating that transcription factors (TFs) bound to these sites were critical in maintaining hTERT transcription during differentiation. Together, our study revealed a dynamic hTERT regulation by chromatin environment and promoter-bound TFs during ESC differentiation.
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25
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Smirnov A, Panatta E, Lena A, Castiglia D, Di Daniele N, Melino G, Candi E. FOXM1 regulates proliferation, senescence and oxidative stress in keratinocytes and cancer cells. Aging (Albany NY) 2017; 8:1384-97. [PMID: 27385468 PMCID: PMC4993337 DOI: 10.18632/aging.100988] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 06/12/2016] [Indexed: 02/07/2023]
Abstract
Several transcription factors, including the master regulator of the epidermis, p63, are involved in controlling human keratinocyte proliferation and differentiation. Here, we report that in normal keratinocytes, the expression of FOXM1, a member of the Forkhead superfamily of transcription factors, is controlled by p63. We observe that, together with p63, FOXM1 strongly contributes to the maintenance of high proliferative potential in keratinocytes, whereas its expression decreases during differentiation, as well as during replicative-induced senescence. Depletion of FOXM1 is sufficient to induce keratinocyte senescence, paralleled by an increased ROS production and an inhibition of ROS-scavenger genes (SOD2, CAT, GPX2, PRDX). Interestingly, FOXM1 expression is strongly reduced in keratinocytes isolated from old human subjects compared with young subjects. FOXM1 depletion sensitizes both normal keratinocytes and squamous carcinoma cells to apoptosis and ROS-induced apoptosis. Together, these data identify FOXM1 as a key regulator of ROS in normal dividing epithelial cells and suggest that squamous carcinoma cells may also use FOXM1 to control oxidative stress to escape premature senescence and apoptosis.
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Affiliation(s)
- Artem Smirnov
- University of Rome "Tor Vergata", Department of Experimental Medicine and Surgery, 00133, Rome, Italy
| | - Emanuele Panatta
- University of Rome "Tor Vergata", Department of Experimental Medicine and Surgery, 00133, Rome, Italy
| | - AnnaMaria Lena
- University of Rome "Tor Vergata", Department of Experimental Medicine and Surgery, 00133, Rome, Italy
| | - Daniele Castiglia
- Istituto Dermopatico dell'Immacolata (IDI-IRCCS), 00166, Rome, Italy
| | - Nicola Di Daniele
- University of "Tor Vergata", Department of Systems Medicine, 00133, Rome, Italy
| | - Gerry Melino
- University of Rome "Tor Vergata", Department of Experimental Medicine and Surgery, 00133, Rome, Italy
| | - Eleonora Candi
- University of Rome "Tor Vergata", Department of Experimental Medicine and Surgery, 00133, Rome, Italy.,Istituto Dermopatico dell'Immacolata (IDI-IRCCS), 00166, Rome, Italy
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26
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Persson CU, von Stedingk K, Bexell D, Merselius M, Braekeveldt N, Gisselsson D, Arsenian-Henriksson M, Påhlman S, Wigerup C. Neuroblastoma patient-derived xenograft cells cultured in stem-cell promoting medium retain tumorigenic and metastatic capacities but differentiate in serum. Sci Rep 2017; 7:10274. [PMID: 28860499 PMCID: PMC5579187 DOI: 10.1038/s41598-017-09662-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 07/19/2017] [Indexed: 12/26/2022] Open
Abstract
Cultured cancer cells serve as important models for preclinical testing of anti-cancer compounds. However, the optimal conditions for retaining original tumor features during in vitro culturing of cancer cells have not been investigated in detail. Here we show that serum-free conditions are critical for maintaining an immature phenotype of neuroblastoma cells isolated from orthotopic patient-derived xenografts (PDXs). PDX cells could be grown either as spheres or adherent on laminin in serum-free conditions with retained patient-specific genomic aberrations as well as tumorigenic and metastatic capabilities. However, addition of serum led to morphological changes, neuronal differentiation and reduced cell proliferation. The epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) were central for PDX cell proliferation and MYCN expression, and also hindered the serum-induced differentiation. Although serum induced a robust expression of neurotrophin receptors, stimulation with their cognate ligands did not induce further sympathetic differentiation, which likely reflects a block in PDX cell differentiation capacity coupled to their tumor genotype. Finally, PDX cells cultured as spheres or adherent on laminin responded similarly to various cytotoxic drugs, suggesting that both conditions are suitable in vitro screening models for neuroblastoma-targeting compounds.
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Affiliation(s)
- Camilla U Persson
- Translational Cancer Research, Lund University Cancer Center at Medicon Village, Lund University, Lund, Sweden
| | | | - Daniel Bexell
- Translational Cancer Research, Lund University Cancer Center at Medicon Village, Lund University, Lund, Sweden
| | - My Merselius
- Translational Cancer Research, Lund University Cancer Center at Medicon Village, Lund University, Lund, Sweden
| | - Noémie Braekeveldt
- Translational Cancer Research, Lund University Cancer Center at Medicon Village, Lund University, Lund, Sweden
| | - David Gisselsson
- Department of Clinical Genetics, Lund University, Department of Pathology, University and Regional Laboratories, Lund, Sweden
| | - Marie Arsenian-Henriksson
- Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, SE-171 77, Stockholm, Sweden
| | - Sven Påhlman
- Translational Cancer Research, Lund University Cancer Center at Medicon Village, Lund University, Lund, Sweden
| | - Caroline Wigerup
- Translational Cancer Research, Lund University Cancer Center at Medicon Village, Lund University, Lund, Sweden.
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27
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Safa M, Jafari L, Alikarami F, Manafi Shabestari R, Kazemi A. Indole-3-carbinol induces apoptosis of chronic myelogenous leukemia cells through suppression of STAT5 and Akt signaling pathways. Tumour Biol 2017. [PMID: 28631564 DOI: 10.1177/1010428317705768] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Signal transducer and activator of transcription 5 and Akt pathways, implicated in signaling transduction downstream of BCR-ABL, play critical roles in the pathogenesis of chronic myeloid leukemia. Therefore, idenication of novel compounds that modulate the activity of such pathways could be a new approach in the treatment of chronic myeloid leukemia. Previous studies have demonstrated that indole-3-carbinol inhibits the proliferation and induces apoptosis of various tumor cells. However, its anticancer activity against chronic myeloid leukemia cells and the underlying mechanism remain unclear. Our data revealed that indole-3-carbinol promoted mitochondrial apoptosis of chronic myeloid leukemia-derived K562 cells, as evidenced by the activation of caspases and poly (ADP-ribose) polymerase cleavage. Treatment with indole-3-carbinol was found to be associated with a decrease in the cellular levels of phospho-Akt and phospho-signal transducer and activator of transcription 5. In addition, real-time polymerase chain reaction analysis showed that the downregulation of genes is regulated by Akt and signal transducer and activator of transcription 5. We also found that treatment with indole-3-carbinol resulted in the activation of the p38 mitogen-activated protein kinase and reduced expression of human telomerase and c-Myc. Collectively, these results demonstrate that the oncogenic signal transducer and activator of transcription 5/Akt pathway is a cellular target for indole-3-carbinol in chronic myeloid leukemia cells. Thus, this clinically tested natural compound can be a potential candidate in the treatment of chronic myeloid leukemia following confirmation with clinical studies.
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Affiliation(s)
- Majid Safa
- 1 Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran.,2 Department of Hematology, Faculty of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Leila Jafari
- 2 Department of Hematology, Faculty of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Fatemeh Alikarami
- 2 Department of Hematology, Faculty of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Rima Manafi Shabestari
- 2 Department of Hematology, Faculty of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Ahmad Kazemi
- 2 Department of Hematology, Faculty of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran
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28
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Functional dissection of breast cancer risk-associated TERT promoter variants. Oncotarget 2017; 8:67203-67217. [PMID: 28978027 PMCID: PMC5620167 DOI: 10.18632/oncotarget.18226] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 05/02/2017] [Indexed: 11/25/2022] Open
Abstract
The multi-cancer susceptibility locus at 5p15.33 includes TERT, encoding the telomerase catalytic subunit. Genome-wide association studies (GWAS) have identified six single nucleotide polymorphisms (SNPs) in the TERT promoter associated with decreased breast cancer risk, although the precise causal variants and their mechanisms of action have remained elusive. Luciferase reporter assays indicated that the protective haplotype reduced TERT promoter activity in human mammary epithelial and cancer cells in an estrogen-independent manner. Using single variant constructs, we identified rs3215401 and rs2853669 as likely functional variants. Silencing of MYC decreased TERT promoter activity but neither MYC nor ETS2 silencing conferred allele-specificity. In chromatin immunoprecipitation experiments, the ETS protein GABPA, but not ETS2 or ELF1, bound rs2853669 in an allele-specific manner in mammary epithelial cells. Investigation of open chromatin in mammoplasty samples suggested involvement of three additional variants, though not rs3215401 or rs2853669. Chromosome conformation capture revealed no interaction of the TERT promoter with regulatory elements in the locus, indicating limited local impact of candidate variants on the TERT promoter. Collectively, our functional studies of the TERT-CLPTM1L breast cancer susceptibility locus describe rs2853669 as a functional variant of this association signal among three other potentially causal variants and demonstrate the versatile mechanisms by which TERT promoter variants may affect breast cancer risk.
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29
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Pan Y, Meng M, Zheng N, Cao Z, Yang P, Xi X, Zhou Q. Targeting of multiple senescence-promoting genes and signaling pathways by triptonide induces complete senescence of acute myeloid leukemia cells. Biochem Pharmacol 2017; 126:34-50. [DOI: 10.1016/j.bcp.2016.11.024] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2016] [Accepted: 11/26/2016] [Indexed: 01/08/2023]
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30
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Khattar E, Tergaonkar V. Transcriptional Regulation of Telomerase Reverse Transcriptase (TERT) by MYC. Front Cell Dev Biol 2017; 5:1. [PMID: 28184371 PMCID: PMC5266692 DOI: 10.3389/fcell.2017.00001] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2016] [Accepted: 01/11/2017] [Indexed: 12/22/2022] Open
Abstract
Telomerase elongates telomeres and is crucial for maintaining genomic stability. While stem cells and cancer cells display high telomerase activity, normal somatic cells lack telomerase activity primarily due to transcriptional repression of telomerase reverse transcriptase (TERT), the catalytic component of telomerase. Transcription factor binding, chromatin status as well as epigenetic modifications at the TERT promoter regulates TERT transcription. Myc is an important transcriptional regulator of TERT that directly controls its expression by promoter binding and associating with other transcription factors. In this review, we discuss the current understanding of the molecular mechanisms behind regulation of TERT transcription by Myc. We also discuss future perspectives in investigating the regulation of Myc at TERT promoter during cancer development.
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Affiliation(s)
- Ekta Khattar
- Laboratory of NFκB Signaling, Institute of Molecular and Cell Biology, ASTAR Singapore, Singapore
| | - Vinay Tergaonkar
- Laboratory of NFκB Signaling, Institute of Molecular and Cell Biology, ASTARSingapore, Singapore; Department of Biochemistry, Yong Loo Lin School of Medicine, National University of SingaporeSingapore, Singapore; Centre for Cancer Biology, University of South Australia and SA PathologyAdelaide, SA, Australia
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31
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Cheng D, Zhao Y, Wang S, Zhang F, Russo M, McMahon SB, Zhu J. Repression of telomerase gene promoter requires human-specific genomic context and is mediated by multiple HDAC1-containing corepressor complexes. FASEB J 2016; 31:1165-1178. [PMID: 27940549 DOI: 10.1096/fj.201601111r] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 11/28/2016] [Indexed: 12/16/2022]
Abstract
The human telomerase reverse transcriptase (hTERT) gene is repressed in most somatic cells, whereas the expression of the mouse mTert gene is widely detected. To understand the mechanisms of this human-specific repression, we constructed bacterial artificial chromosome (BAC) reporters using human and mouse genomic DNAs encompassing the TERT genes and neighboring loci. Upon chromosomal integration, the hTERT, but not the mTert, reporter was stringently repressed in telomerase-negative human cells in a histone deacetylase (HDAC)-dependent manner, replicating the expression of their respective endogenous genes. In chimeric BACs, the mTert promoter became strongly repressed in the human genomic context, but the hTERT promoter was highly active in the mouse genomic context. Furthermore, an unrelated herpes simplex virus-thymidine kinase (HSV-TK) promoter was strongly repressed in the human, but not in the mouse, genomic context. These results demonstrated that the repression of hTERT gene was dictated by distal elements and its chromatin environment. This repression depended on class I HDACs and involved multiple corepressor complexes, including HDAC1/2-containing Sin3B, nucleosome remodeling and histone deacetylase (NuRD), and corepressor of RE1 silencing transcription factor (CoREST) complexes. Together, our data indicate that the lack of telomerase expression in most human somatic cells results from its repressive genomic environment, providing new insight into the mechanism of long-recognized differential telomerase regulation in mammalian species.-Cheng, D., Zhao, Y., Wang, S., Zhang, F., Russo, M., McMahon, S. B., Zhu, J. Repression of telomerase gene promoter requires human-specific genomic context and is mediated by multiple HDAC1-containing corepressor complexes.
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Affiliation(s)
- De Cheng
- Department of Pharmaceutical Sciences, Washington State University College of Pharmacy, Spokane, Washington, USA
| | - Yuanjun Zhao
- Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USA; and
| | - Shuwen Wang
- Department of Pharmaceutical Sciences, Washington State University College of Pharmacy, Spokane, Washington, USA
| | - Fan Zhang
- Department of Pharmaceutical Sciences, Washington State University College of Pharmacy, Spokane, Washington, USA
| | - Mariano Russo
- Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USA; and
| | - Steven B McMahon
- Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Jiyue Zhu
- Department of Pharmaceutical Sciences, Washington State University College of Pharmacy, Spokane, Washington, USA;
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32
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Heidenreich B, Kumar R. TERT promoter mutations in telomere biology. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2016; 771:15-31. [PMID: 28342451 DOI: 10.1016/j.mrrev.2016.11.002] [Citation(s) in RCA: 130] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 11/10/2016] [Indexed: 02/07/2023]
Abstract
Telomere repeats at chromosomal ends, critical to genome integrity, are maintained through an elaborate network of proteins and pathways. Shelterin complex proteins shield telomeres from induction of DNA damage response to overcome end protection problem. A specialized ribonucleic protein, telomerase, maintains telomere homeostasis through repeat addition to counter intrinsic shortcomings of DNA replication that leads to gradual sequence shortening in successive mitoses. The biogenesis and recruitment of telomerase composed of telomerase reverse transcriptase (TERT) subunit and an RNA component, takes place through the intricate machinery that involves an elaborate number of molecules. The synthesis of telomeres remains a controlled and limited process. Inherited mutations in the molecules involved in the process directly or indirectly cause telomeropathies. Telomerase, while present in stem cells, is deactivated due to epigenetic silencing of the rate-limiting TERT upon differentiation in most of somatic cells with a few exceptions. However, in most of the cancer cells telomerase reactivation remains a ubiquitous process and constitutes one of the major hallmarks. Discovery of mutations within the core promoter of the TERT gene that create de novo binding sites for E-twenty-six (ETS) transcription factors provided a mechanism for cancer-specific telomerase reactivation. The TERT promoter mutations occur mainly in tumors from tissues with low rates of self-renewal. In melanoma, glioma, hepatocellular carcinoma, urothelial carcinoma and others, the promoter mutations have been shown to define subsets of patients with adverse disease outcomes, associate with increased transcription of TERT, telomerase reactivation and affect telomere length; in stem cells the mutations inhibit TERT silencing following differentiation into adult cells. The TERT promoter mutations cause an epigenetic switch on the mutant allele along with recruitment of pol II following the binding of GABPA/B1 complex that leads to mono-allelic expression. Thus, the TERT promoter mutations hold potential as biomarkers as well as future therapeutic targets.
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Affiliation(s)
| | - Rajiv Kumar
- Division of Molecular Genetic Epidemiology; German Consortium for Translational Cancer Research (DKTK), German Cancer Research Center, 69120 Heidelberg, Germany.
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33
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Ko E, Seo HW, Jung ES, Kim BH, Jung G. The TERT promoter SNP rs2853669 decreases E2F1 transcription factor binding and increases mortality and recurrence risks in liver cancer. Oncotarget 2016; 7:684-99. [PMID: 26575952 PMCID: PMC4808026 DOI: 10.18632/oncotarget.6331] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 10/27/2015] [Indexed: 01/09/2023] Open
Abstract
A common single-nucleotide polymorphism in the telomerase reverse transcriptase (TERT) promoter, rs2853669 influences patient survival rates and the risk of developing cancer. Recently, several lines of evidence suggest that the rs2853669 suppresses TERT promoter mutation-mediated TERT expression levels and cancer mortality as well as recurrence rates. However, no reports are available on the impact of rs2853669 on TERT expression in hepatocellular carcinoma (HCC) and its association with patient survival. Here, we found that HCC-related overall and recurrence-free survival rates were not associated with TERT promoter mutation individually, but rs2853669 and the TERT promoter mutation in combination were associated with poor survival rates. TERT mRNA expression and telomere fluorescence levels were greater in patients with HCC who had both the combination. The combination caused TERT promoter methylation through regulating the binding of DNA methyltransferase 1 and histone deacetylase 1 to the TERT promoter in HCC cell lines. The TERT expression level was significantly higher in HCC tumor with a methylated promoter than in that with an unmethylated promoter. In conclusion, we demonstrate a substantial role for the rs2853669 in HCC with TERT promoter mutation, which suggests that the combination of the rs2853669 and the mutation indicate poor prognoses in liver cancer.
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Affiliation(s)
- Eunkyong Ko
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Gwanak-gu, Seoul, 151-747, South Korea
| | - Hyun-Wook Seo
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Gwanak-gu, Seoul, 151-747, South Korea
| | - Eun Sun Jung
- Department of Pathology, Seoul St. Mary's Hospital, The Catholic University of Korea, Seocho-Gu, Seoul, 133-782, South Korea
| | - Baek-hui Kim
- Department of Pathology, Korea University Guro Hospital, Korea University College of Medicine, Seoul, 152-703, South Korea
| | - Guhung Jung
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Gwanak-gu, Seoul, 151-747, South Korea
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34
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Hosseinzadeh Anvar L, Hosseini-Asl S, Mohammadzadeh-Vardin M, Sagha M. The Telomerase Activity of Selenium-Induced Human Umbilical Cord Mesenchymal Stem Cells Is Associated with Different Levels of c-Myc and p53 Expression. DNA Cell Biol 2016; 36:34-41. [PMID: 27813686 DOI: 10.1089/dna.2016.3411] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Selenium-as a trace element-is nutritionally essential for humans. It prevents cancerous growth by inhibiting the telomerase activity but the mechanism involved in regulation of telomerase activity in normal telomerase-positive cells remains to be elucidated. Here, we find out whether the effect of sodium selenite and selenomethionine on telomerase activity in human umbilical cord-derived mesenchymal stem cells (hUCMSCs) is associated with different levels of c-Myc and p53 expression. The use of different staining methods including ethidium bromide/acridine orange and DAPI in addition to telomeric repeat amplification protocol assay and real-time PCR indicated that different forms of selenium have opposite impacts on c-Myc and p53 expressions in both hUCMSCs and AGS, a gastric adenocarcinoma cell line, as a positive control. Our findings suggest that the signaling pathways involved in the regulation of telomerase activity in malignant and normal telomerase-positive cell types are somewhat different, at least on the c-Myc and P53 expression levels.
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Affiliation(s)
- Leila Hosseinzadeh Anvar
- 1 Research Laboratory for Embryology and Stem Cells, Department of Anatomical Sciences and Pathology, Faculty of Medicine, Ardabil University of Medical Sciences , Ardabil, Iran .,2 Laboratory of Medical Genetics, Imam Khomeini Hospital, Ardabil University of Medical Sciences , Ardabil, Iran
| | - Saeid Hosseini-Asl
- 2 Laboratory of Medical Genetics, Imam Khomeini Hospital, Ardabil University of Medical Sciences , Ardabil, Iran
| | - Mohammad Mohammadzadeh-Vardin
- 1 Research Laboratory for Embryology and Stem Cells, Department of Anatomical Sciences and Pathology, Faculty of Medicine, Ardabil University of Medical Sciences , Ardabil, Iran
| | - Mohsen Sagha
- 1 Research Laboratory for Embryology and Stem Cells, Department of Anatomical Sciences and Pathology, Faculty of Medicine, Ardabil University of Medical Sciences , Ardabil, Iran
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35
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Qin QP, Qin JL, Meng T, Lin WH, Zhang CH, Wei ZZ, Chen JN, Liu YC, Liang H, Chen ZF. High in vivo antitumor activity of cobalt oxoisoaporphine complexes by targeting G-quadruplex DNA, telomerase and disrupting mitochondrial functions. Eur J Med Chem 2016; 124:380-392. [DOI: 10.1016/j.ejmech.2016.08.063] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Revised: 08/25/2016] [Accepted: 08/26/2016] [Indexed: 12/27/2022]
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36
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Kang HJ, Cui Y, Yin H, Scheid A, Hendricks WPD, Schmidt J, Sekulic A, Kong D, Trent JM, Gokhale V, Mao H, Hurley LH. A Pharmacological Chaperone Molecule Induces Cancer Cell Death by Restoring Tertiary DNA Structures in Mutant hTERT Promoters. J Am Chem Soc 2016; 138:13673-13692. [PMID: 27643954 DOI: 10.1021/jacs.6b07598] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Activation of human telomerase reverse transcriptase (hTERT) is necessary for limitless replication in tumorigenesis. Whereas hTERT is transcriptionally silenced in normal cells, most tumor cells reactivate hTERT expression by alleviating transcriptional repression through diverse genetic and epigenetic mechanisms. Transcription-activating hTERT promoter mutations have been found to occur at high frequencies in multiple cancer types. These mutations have been shown to form new transcription factor binding sites that drive hTERT expression, but this model cannot fully account for differences in wild-type (WT) and mutant promoter activation and has not yet enabled a selective therapeutic strategy. Here, we demonstrate a novel mechanism by which promoter mutations activate hTERT transcription, which also sheds light on a unique therapeutic opportunity. Promoter mutations occur in a core promoter region that forms tertiary structures consisting of a pair of G-quadruplexes involved in transcriptional silencing. We show that promoter mutations exert a detrimental effect on the folding of one of these G-quadruplexes, resulting in a nonfunctional silencer element that alleviates transcriptional repression. We have also identified a small drug-like pharmacological chaperone (pharmacoperone) molecule, GTC365, that acts at an early step in the G-quadruplex folding pathway to redirect mutant promoter G-quadruplex misfolding, partially reinstate the correct folding pathway, and reduce hTERT activity through transcriptional repression. This transcription-mediated repression produces cancer cell death through multiple routes including both induction of apoptosis through inhibition of hTERT's role in regulating apoptosis-related proteins and induction of senescence by decreasing telomerase activity and telomere length. We demonstrate the selective therapeutic potential of this strategy in melanoma cells that overexpress hTERT.
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Affiliation(s)
- Hyun-Jin Kang
- University of Arizona , College of Pharmacy, 1703 East Mabel Street, Tucson, Arizona 85721, United States
| | - Yunxi Cui
- Department of Chemistry and Biochemistry and School of Biomedical Sciences, Kent State University , Kent, Ohio 44242, United States
| | - Holly Yin
- Translational Genomics Research Institute , 445 North Fifth Street, Phoenix, Arizona 85004, United States
| | - Amy Scheid
- College of Science, University of Arizona , 1040 East Fourth Street, Tucson, Arizona 85721, United States
| | - William P D Hendricks
- Translational Genomics Research Institute , 445 North Fifth Street, Phoenix, Arizona 85004, United States
| | - Jessica Schmidt
- Department of Dermatology, Mayo Clinic , 13400 East Shea Boulevard, Scottsdale, Arizona 85259, United States
| | - Aleksandar Sekulic
- Department of Dermatology, Mayo Clinic , 13400 East Shea Boulevard, Scottsdale, Arizona 85259, United States
| | - Deming Kong
- State Key Laboratory of Medicinal Chemical Biology, College of Chemistry, Nankai University , Tianjin 300071, People's Republic of China
| | - Jeffrey M Trent
- Translational Genomics Research Institute , 445 North Fifth Street, Phoenix, Arizona 85004, United States
| | - Vijay Gokhale
- BIO5 Institute , 1657 East Helen Street, Tucson, Arizona 85721, United States
| | - Hanbin Mao
- Department of Chemistry and Biochemistry and School of Biomedical Sciences, Kent State University , Kent, Ohio 44242, United States
| | - Laurence H Hurley
- University of Arizona , College of Pharmacy, 1703 East Mabel Street, Tucson, Arizona 85721, United States.,BIO5 Institute , 1657 East Helen Street, Tucson, Arizona 85721, United States.,Arizona Cancer Center , 1515 North Campbell Avenue, Tucson, Arizona 85724, United States
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37
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Akıncılar SC, Khattar E, Boon PLS, Unal B, Fullwood MJ, Tergaonkar V. Long-Range Chromatin Interactions Drive Mutant TERT Promoter Activation. Cancer Discov 2016; 6:1276-1291. [PMID: 27650951 DOI: 10.1158/2159-8290.cd-16-0177] [Citation(s) in RCA: 109] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 09/13/2016] [Indexed: 11/16/2022]
Abstract
Cancer-specific TERT promoter mutations (-146C>T and -124C>T) have been linked to reactivation of the epigenetically silenced telomerase reverse transcriptase gene (TERT). Understanding how these single-nucleotide alterations drive TERT reactivation is a fundamental unanswered question and is key for making successful therapeutics. We show that unlike wild-type promoters, recruitment of the transcription factor GABPA specifically to mutant TERT promoters mediates long-range chromatin interaction and enrichment of active histone marks, and hence drives TERT transcription. CRISPR-mediated reversal of mutant TERT promoters, or deletion of its long-range interacting chromatin, abrogates GABPA binding and long-range interactions, leading to depletion of active histone marks, loss of POL2 recruitment, and suppression of TERT transcription. In contrast, de novo introduction of a TERT promoter mutation enables GABPA binding and upregulation of TERT via long-range interactions, acquisition of active histone marks, and subsequent POL2 recruitment. This study provides a unifying mechanistic insight into activation of mutant TERT promoters across various human cancers. SIGNIFICANCE This study identifies a key mechanism by which cancer-specific mutant TERT promoters cause reactivation of TERT Because the mechanism uncovered here is not utilized by promoters that drive TERT in normal cells, this mechanism could be exploited to make inhibitors which have the potential to block telomerase function and hence the progression of up to 90% of human cancers. Cancer Discov; 6(11); 1276-91. ©2016 AACR.See related commentary by Min and Shay, p. 1212This article is highlighted in the In This Issue feature, p. 1197.
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Affiliation(s)
- Semih Can Akıncılar
- Division of Cancer Genetics and Therapeutics, Laboratory of NFκB Signaling, Institute of Molecular and Cell Biology (IMCB), A*STAR (Agency for Science, Technology and Research), Singapore.,Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore (NUS), Singapore
| | - Ekta Khattar
- Division of Cancer Genetics and Therapeutics, Laboratory of NFκB Signaling, Institute of Molecular and Cell Biology (IMCB), A*STAR (Agency for Science, Technology and Research), Singapore
| | | | - Bilal Unal
- Division of Cancer Genetics and Therapeutics, Laboratory of NFκB Signaling, Institute of Molecular and Cell Biology (IMCB), A*STAR (Agency for Science, Technology and Research), Singapore.,Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore (NUS), Singapore
| | | | - Vinay Tergaonkar
- Division of Cancer Genetics and Therapeutics, Laboratory of NFκB Signaling, Institute of Molecular and Cell Biology (IMCB), A*STAR (Agency for Science, Technology and Research), Singapore. .,Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore (NUS), Singapore.,Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, Australia
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38
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Zhang F, Cheng D, Wang S, Zhu J. Human Specific Regulation of the Telomerase Reverse Transcriptase Gene. Genes (Basel) 2016; 7:genes7070030. [PMID: 27367732 PMCID: PMC4962000 DOI: 10.3390/genes7070030] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 06/15/2016] [Accepted: 06/17/2016] [Indexed: 12/19/2022] Open
Abstract
Telomerase, regulated primarily by the transcription of its catalytic subunit telomerase reverse transcriptase (TERT), is critical for controlling cell proliferation and tissue homeostasis by maintaining telomere length. Although there is a high conservation between human and mouse TERT genes, the regulation of their transcription is significantly different in these two species. Whereas mTERT expression is widely detected in adult mice, hTERT is expressed at extremely low levels in most adult human tissues and cells. As a result, mice do not exhibit telomere-mediated replicative aging, but telomere shortening is a critical factor of human aging and its stabilization is essential for cancer development in humans. The chromatin environment and epigenetic modifications of the hTERT locus, the binding of transcriptional factors to its promoter, and recruitment of nucleosome modifying complexes all play essential roles in restricting its transcription in different cell types. In this review, we will discuss recent progress in understanding the molecular mechanisms of TERT regulation in human and mouse tissues and cells, and during cancer development.
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Affiliation(s)
- Fan Zhang
- Department of Pharmaceutical Sciences, Washington State University College of Pharmacy, PO Box 1495, Spokane, WA 99210, USA.
| | - De Cheng
- Department of Pharmaceutical Sciences, Washington State University College of Pharmacy, PO Box 1495, Spokane, WA 99210, USA.
| | - Shuwen Wang
- Department of Pharmaceutical Sciences, Washington State University College of Pharmacy, PO Box 1495, Spokane, WA 99210, USA.
| | - Jiyue Zhu
- Department of Pharmaceutical Sciences, Washington State University College of Pharmacy, PO Box 1495, Spokane, WA 99210, USA.
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Kim JY, An YM, Park JH. Role of GLTSCR2 in the regulation of telomerase activity and chromosome stability. Mol Med Rep 2016; 14:1697-703. [PMID: 27357325 DOI: 10.3892/mmr.2016.5427] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 01/11/2016] [Indexed: 11/05/2022] Open
Abstract
Telomerase is essential for regulating telomeres, and its activation is a critical step in cellular immortalization and tumorigenesis. The transcriptional activation of human telomerase reverse transcriptase (hTERT) is critical for telomerase expression. Although several transcriptional activators have been identified, factors responsible for enhancing the hTERT promoter remain to be fully elucidated. In the present study, the role of glioma tumor-suppressor candidate region gene 2 (GLTSCR2) in telomerase regulation was analyzed. A doxycyclin-inducible green fluorescent protein (GFP)-tagged GLTSCR2-expressing adenovirus (Ad‑GLT/GFP) was used for the transduction of SK‑Hep‑1 and T98G cancer cells, and normal human umbilical vein endothelial cells. Changes in telomerase activity using telomere repeat amplification protocol assay were assessed, and the gene expression levels of hTERT were then examined. To investigate chromosome instability and senescence, Giemsa and β-galactosidase staining was performed. The results revealed that overexpression of GLTSCR2 significantly increased telomerase activity in the cancer and normal cell lines. This increase was consistent with increases in the protein and mRNA expression levels of hTERT. In luciferase assays, the hTERT promoter was activated by GLTSCR2. Knockdown of GLTSCR2 led to the downregulation of telomerase activity, abnormal nuclear morphology as a marker of chromosome instability, significant suppression of growth rate, alterations in cellular morphology and, eventually, cellular senescence. Taken together, the results of the present study suggested that GLTSCR2 is crucially involved in the positive regulation of telomerase and chromosome stability.
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Affiliation(s)
- Jee-Youn Kim
- Department of Pathology, School of Medicine, Kyung Hee University, Seoul 130‑701, Republic of Korea
| | - Yong-Min An
- Department of Pathology, School of Medicine, Kyung Hee University, Seoul 130‑701, Republic of Korea
| | - Jae-Hoon Park
- Department of Pathology, School of Medicine, Kyung Hee University, Seoul 130‑701, Republic of Korea
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40
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Ovarian cancer treatment with a tumor-targeting and gene expression-controllable lipoplex. Sci Rep 2016; 6:23764. [PMID: 27026065 PMCID: PMC4824455 DOI: 10.1038/srep23764] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Accepted: 03/14/2016] [Indexed: 02/05/2023] Open
Abstract
Overexpression of folate receptor alpha (FRα) and high telomerase activity are considered to be the characteristics of ovarian cancers. In this study, we developed FRα-targeted lipoplexes loaded with an hTERT promoter-regulated plasmid that encodes a matrix protein (MP) of the vesicular stomatitis virus, F-LP/pMP(2.5), for application in ovarian cancer treatment. We first characterized the pharmaceutical properties of F-LP/pMP(2.5). The efficient expression of the MP-driven hTERT promoter in SKOV-3 cells was determined after an in-vitro transfection assay, which was significantly increased compared with a non-modified LP/pMP(2.5) group. F-LP/pMP(2.5) treatment significantly inhibited the growth of tumors and extended the survival of mice in a SKOV-3 tumor model compared with other groups. Such an anti-tumor effect was due to the increased expression of MP in tumor tissue, which led to the induction of tumor cell apoptosis, inhibition of tumor cell proliferation and suppression of tumor angiogenesis. Furthermore, a preliminary safety evaluation demonstrated a good safety profile of F-LP/pMP(2.5) as a gene therapy agent. Therefore, FRα-targeted lipoplexes with therapeutic gene expression regulated by an hTERT promoter might be a promising gene therapy agent and a potential translational candidate for the clinical treatment of ovarian cancer.
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41
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Valentijn LJ, Koster J, Zwijnenburg DA, Hasselt NE, van Sluis P, Volckmann R, van Noesel MM, George RE, Tytgat GAM, Molenaar JJ, Versteeg R. TERT rearrangements are frequent in neuroblastoma and identify aggressive tumors. Nat Genet 2015; 47:1411-4. [PMID: 26523776 DOI: 10.1038/ng.3438] [Citation(s) in RCA: 261] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 10/09/2015] [Indexed: 12/13/2022]
Abstract
Whole-genome sequencing detected structural rearrangements of TERT in 17 of 75 high-stage neuroblastomas, with five cases resulting from chromothripsis. Rearrangements were associated with increased TERT expression and targeted regions immediately up- and downstream of TERT, positioning a super-enhancer close to the breakpoints in seven cases. TERT rearrangements (23%), ATRX deletions (11%) and MYCN amplifications (37%) identify three almost non-overlapping groups of high-stage neuroblastoma, each associated with very poor prognosis.
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Affiliation(s)
- Linda J Valentijn
- Department of Oncogenomics, Academic Medical Center, Amsterdam, the Netherlands
| | - Jan Koster
- Department of Oncogenomics, Academic Medical Center, Amsterdam, the Netherlands
| | - Danny A Zwijnenburg
- Department of Oncogenomics, Academic Medical Center, Amsterdam, the Netherlands
| | - Nancy E Hasselt
- Department of Oncogenomics, Academic Medical Center, Amsterdam, the Netherlands
| | - Peter van Sluis
- Department of Oncogenomics, Academic Medical Center, Amsterdam, the Netherlands
| | - Richard Volckmann
- Department of Oncogenomics, Academic Medical Center, Amsterdam, the Netherlands
| | - Max M van Noesel
- Princess Máxima Center for Pediatric Oncology, Utrecht, the Netherlands
| | - Rani E George
- Department of Pediatric Hematology/Oncology, Dana-Farber Cancer Institute and Boston Children's Hospital, Boston, Massachusetts, USA.,Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
| | - Godelieve A M Tytgat
- Princess Máxima Center for Pediatric Oncology, Utrecht, the Netherlands.,Department of Pediatric Oncology, Academic Medical Center, Amsterdam, the Netherlands
| | - Jan J Molenaar
- Department of Oncogenomics, Academic Medical Center, Amsterdam, the Netherlands
| | - Rogier Versteeg
- Department of Oncogenomics, Academic Medical Center, Amsterdam, the Netherlands
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42
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Cheng D, Zhao Y, Wang S, Jia W, Kang J, Zhu J. Human Telomerase Reverse Transcriptase (hTERT) Transcription Requires Sp1/Sp3 Binding to the Promoter and a Permissive Chromatin Environment. J Biol Chem 2015; 290:30193-203. [PMID: 26487723 DOI: 10.1074/jbc.m115.662221] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Indexed: 12/14/2022] Open
Abstract
The transcription of human telomerase gene hTERT is regulated by transcription factors (TFs), including Sp1 family proteins, and its chromatin environment. To understand its regulation in a relevant chromatin context, we employed bacterial artificial chromosome reporters containing 160 kb of human genomic sequence containing the hTERT gene. Upon chromosomal integration, the bacterial artificial chromosomes recapitulated endogenous hTERT expression, contrary to transient reporters. Sp1/Sp3 expression did not correlate with hTERT promoter activity, and these TFs bound to the hTERT promoters in both telomerase-positive and telomerase-negative cells. Mutation of the proximal GC-box resulted in a dramatic decrease of hTERT promoter activity, and mutations of all five GC-boxes eliminated its transcriptional activity. Neither mutations of GC-boxes nor knockdown of endogenous Sp1 impacted promoter binding by other TFs, including E-box-binding proteins, and histone acetylation and trimethylation of histone H3K9 at the hTERT promoter in telomerase-positive and -negative cells. The result indicated that promoter binding by Sp1/Sp3 was essential, but not a limiting step, for hTERT transcription. hTERT transcription required a permissive chromatin environment. Importantly, our data also revealed different functions of GC-boxes and E-boxes in hTERT regulation; although GC-boxes were essential for promoter activity, factors bound to the E-boxes functioned to de-repress hTERT promoter.
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Affiliation(s)
- De Cheng
- From the Department of Pharmaceutical Sciences, Washington State University College of Pharmacy, Spokane, Washington 99210
| | - Yuanjun Zhao
- the Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033, and
| | - Shuwen Wang
- From the Department of Pharmaceutical Sciences, Washington State University College of Pharmacy, Spokane, Washington 99210
| | - Wenwen Jia
- the School of Life Sciences and Technology, Tongji University, Shanghai 200092, China
| | - Jiuhong Kang
- the School of Life Sciences and Technology, Tongji University, Shanghai 200092, China
| | - Jiyue Zhu
- From the Department of Pharmaceutical Sciences, Washington State University College of Pharmacy, Spokane, Washington 99210, the Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033, and
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43
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Mechanism studies on anti-HepG2 cell proliferation of phenanthroline derivatives as G-quadruplex DNA stabilizers. Bioorg Med Chem Lett 2015; 25:3798-803. [DOI: 10.1016/j.bmcl.2015.07.085] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 07/06/2015] [Accepted: 07/25/2015] [Indexed: 12/13/2022]
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44
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Hara T, Mizuguchi M, Fujii M, Nakamura M. Krüppel-like factor 2 represses transcription of the telomerase catalytic subunit human telomerase reverse transcriptase (hTERT) in human T cells. J Biol Chem 2015; 290:8758-63. [PMID: 25694435 DOI: 10.1074/jbc.m114.610386] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2014] [Indexed: 11/06/2022] Open
Abstract
In normal human T cells, telomerase activity is strictly regulated. T cells are thought to express telomerase to avoid replicative senescence, unlike most normal somatic cells with definite replicative lifespan. T cells in blood and tissues are usually in a state of quiescence without expression of the limiting catalytic subunit of telomerase, human telomerase reverse transcriptase (hTERT). In contrast to activation, repression of hTERT transcription has not been studied well. Our previous studies have found an hTERT promoter element with repressive function. Here we identified KLF2, which represses hTERT transcription by binding to the putative promoter element. KLF2 and hTERT exhibited reciprocal mRNA expression patterns in primary human T cells. In activated T cells, KLF2 binding to the hTERT promoter was eliminated, relieving the repression of hTERT transcription found in resting T cells. Our results suggest that KLF2 is involved in strict repression of hTERT expression through binding to the promoter in primary human T cells.
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Affiliation(s)
- Toshifumi Hara
- From the Human Gene Sciences Center, Tokyo Medical and Dental University, Tokyo 113-8510 and the Division of Virology, Niigata University Graduate School of Medicine and Dental Sciences, Niigata 951-8510, Japan
| | - Mariko Mizuguchi
- From the Human Gene Sciences Center, Tokyo Medical and Dental University, Tokyo 113-8510 and
| | - Masahiro Fujii
- the Division of Virology, Niigata University Graduate School of Medicine and Dental Sciences, Niigata 951-8510, Japan
| | - Masataka Nakamura
- From the Human Gene Sciences Center, Tokyo Medical and Dental University, Tokyo 113-8510 and
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