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Bao Y, Pan Z, Zhao L, Qiu J, Cheng J, Liu L, Qian D. BIBR1532 combined with radiotherapy induces ferroptosis in NSCLC cells and activates cGAS-STING pathway to promote anti-tumor immunity. J Transl Med 2024; 22:519. [PMID: 38816831 PMCID: PMC11138045 DOI: 10.1186/s12967-024-05331-3] [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: 12/08/2023] [Accepted: 05/18/2024] [Indexed: 06/01/2024] Open
Abstract
BACKGROUND Telomerase, by safeguarding damaged telomeres and bolstering DNA damage repair, has the capacity to heighten the radioresistance of tumour cells. Thus, in turn, can compromise the efficacy of radiotherapy (RT) and radioimmunotherapy. Our previous studies have revealed that the highly selective telomerase inhibitor, BIBR1532, possesses the potential to enhance the radiosensitivity of Non-small cell lung cancer (NSCLC). In this study, we delve further into the impact of BIBR1532 on the immune activation induced by RT and elucidate the underlying mechanisms. METHODS Biological information analyses, immunofluorescence assays, western blot assays, flow cytometry analysis were conducted to elucidate the functions of the combination of BIBR1532 with radiotherapy in NSCLC. Intracellular levels of lipid peroxides, glutathione, malondialdehyde, and Fe2+ were measured as indicators of ferroptosis status. Both in vitro and in vivo studies were conducted to examine the antitumor effects. RESULTS Our findings indicate that the confluence of BIBR1532 with RT significantly augments the activation of the cGAS-STING pathway in both in vivo and in vitro settings, thereby fostering an effective anti-tumoral immune response. The effects can be ascribed to two key processes. Firstly, ionizing radiation, in precipitating DNA double-strand breaks (DSBs), prompts the release of tumour-derived double-stranded DNA (dsDNA) into the cytoplasm. Subsequently, BIBR1532 amplifies the activation of antigen-presenting cells by dsDNA post-RT and instigates the cGAS-STING pathway. Secondly, BIBR1532 enhances the ferroptosis response in NSCLC following RT, thereby promoting unrestrained lipid peroxidation and elevated levels of reactive oxygen species (ROS) within tumour cells. This ultimately leads to mitochondrial stress and the release of endogenous mitochondrial DNA (mtDNA) into the cytoplasm, thus facilitating the activation of the STING pathway and the induction of a type I interferon (IFN)-linked adaptive immune response. CONCLUSION This study underscores the potential of BIBR1532 as an efficacious and safe radiosensitizer and radioimmunotherapy synergist, providing robust preclinical research evidence for the treatment of NSCLC.
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Affiliation(s)
- Yawei Bao
- Department of Radiation Oncology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, 230001, China
- Core Facility Center, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China
| | - Zhipeng Pan
- Department of Oncology, The Second Affiliated Hospital of Anhui Medical University, Hefei, Anhui, 230000, China
| | - Luqi Zhao
- Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, TX, 77204-5039, USA
| | - Jieping Qiu
- Department of Radiation Oncology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, 230001, China
- Core Facility Center, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China
| | - Jingjing Cheng
- Department of Radiation Oncology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, 230001, China
- Core Facility Center, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China
| | - Lei Liu
- Department of Radiation Oncology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, 230001, China
- Core Facility Center, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China
| | - Dong Qian
- Department of Radiation Oncology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, 230001, China.
- Core Facility Center, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China.
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2
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Li X, Feng C, Peng S. Epigenetics alternation in lung fibrosis and lung cancer. Front Cell Dev Biol 2022; 10:1060201. [PMID: 36420141 PMCID: PMC9676258 DOI: 10.3389/fcell.2022.1060201] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 10/20/2022] [Indexed: 09/10/2023] Open
Abstract
Respiratory disease including interstitial lung diseases (ILDs) and lung cancer is a group of devastating diseases that linked with increased morbidity and healthcare burden. However, respiratory diseases cannot be fully explained by the alternation of genetic information. Genetic studies described that epigenetic mechanisms also participate to transmit genetic information. Recently, many studies demonstrated the role of altered epigenetic modification in the pathogenesis of lung cancer and pulmonary fibrosis. Due to lacking effective medication, the underlying pathophysiological processes and causal relationships of lung diseases with epigenetic mechanisms still need to be better understood. Our present review provided a systematic revision of current knowledge concerning diverse epigenetic aberrations in major lung diseases, with special emphasis on DNA methylation, histone modifications, lncRNAs profiles, telomere patterns, as well as chromatin-remodelling complexes. We believed that a new target therapy for lung disease based on findings of the involved epigenetic pathway is a promising future direction.
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Affiliation(s)
- Xueren Li
- Department of Respiratory Medicine, Tianjin Haihe Hospital, Tianjin, China
- Tianjin Institute of Respiratory Diseases, Tianjin, China
| | - Chunjing Feng
- The Institute Includes H&B(Tianjin) Stem Cell Research Institute, Tianjin, China
| | - Shouchun Peng
- Department of Respiratory Medicine, Tianjin Haihe Hospital, Tianjin, China
- Tianjin Institute of Respiratory Diseases, Tianjin, China
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3
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Wang R, Li J, Zhang C, Guan X, Qin B, Jin R, Qin L, Xu S, Zhang X, Liu R, Ye Q, Cheng L. Lactate Dehydrogenase B Is Required for Pancreatic Cancer Cell Immortalization Through Activation of Telomerase Activity. Front Oncol 2022; 12:821620. [PMID: 35669414 PMCID: PMC9163669 DOI: 10.3389/fonc.2022.821620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 04/22/2022] [Indexed: 11/13/2022] Open
Abstract
Telomerase activity is elevated in most cancer cells and is required for telomere length maintenance and immortalization of cancer cells. Glucose metabolic reprogramming is a hallmark of cancer and accompanied with increased expression of key metabolic enzymes. Whether these enzymes influence telomerase activity and cell immortalization remains unclear. In the current study, we screened metabolic enzymes using telomerase activity assay and identified lactate dehydrogenase B (LDHB) as a regulator of telomerase activity. Sodium lactate and sodium pyruvate did not influence telomerase activity, indicating LDHB regulates telomerase activity independent of its metabolism regulating function. Further studies revealed that LDHB directly interacted with TERT and regulated the interaction between TERT and TERC. Additionally, long-term knockdown of LDHB inhibited cancer cell growth and induced cell senescence in vitro and in vivo. Higher LDHB expression was detected in pancreatic cancer tissues compared with that in adjacent normal tissues and expression of LDHB correlated negatively with prognosis. Thus, we identified LDHB as the first glucose metabolic enzyme contributing to telomerase activity and pancreatic cancer cell immortalization.
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Affiliation(s)
- Ruiguan Wang
- Department of Cell Engineering, Beijing Institute of Biotechnology, Beijing, China
- Faculty of Hepato-Pancreato-Biliary Surgery, Chinese People's Liberation Army (PLA) General Hospital, Beijing, China
- Department of Hepatobiliary Surgery, the Eight Medical Center, Chinese People's Liberation Army (PLA) General Hospital, Beijing, China
| | - Jiangbo Li
- Department of Cell Engineering, Beijing Institute of Biotechnology, Beijing, China
| | - Changjian Zhang
- Department of Cell Engineering, Beijing Institute of Biotechnology, Beijing, China
- Senior Department of Otolaryngology-Head & Neck Surgery, the Sixth Medical Center, Chinese People's Liberation Army (PLA) General Hospital, Beijing, China
| | - Xin Guan
- Strategic Support Force Medical Center, Beijing, China
| | - Boyu Qin
- Department of Medical Oncology, the First Medical Centre, Chinese People's Liberation Army (PLA) General Hospital, Beijing, China
| | - Rui Jin
- Department of Cell Engineering, Beijing Institute of Biotechnology, Beijing, China
| | - Lingmei Qin
- Department of Cell Engineering, Beijing Institute of Biotechnology, Beijing, China
| | - Shanrong Xu
- Department of Cell Engineering, Beijing Institute of Biotechnology, Beijing, China
- School of Life Science, Anqing Normal University, Anqing, China
| | - Xiaona Zhang
- Department of Cell Engineering, Beijing Institute of Biotechnology, Beijing, China
- College of Life Sciences, Capital Normal University, Beijing, China
| | - Rong Liu
- Faculty of Hepato-Pancreato-Biliary Surgery, Chinese People's Liberation Army (PLA) General Hospital, Beijing, China
- Department of Hepatobiliary Surgery, the Eight Medical Center, Chinese People's Liberation Army (PLA) General Hospital, Beijing, China
- *Correspondence: Long Cheng, ; Qinong Ye, ; Rong Liu,
| | - Qinong Ye
- Department of Cell Engineering, Beijing Institute of Biotechnology, Beijing, China
- *Correspondence: Long Cheng, ; Qinong Ye, ; Rong Liu,
| | - Long Cheng
- Department of Cell Engineering, Beijing Institute of Biotechnology, Beijing, China
- *Correspondence: Long Cheng, ; Qinong Ye, ; Rong Liu,
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Han S, Ma X, Fang J. [Clinical Application and Challenges of Telomere and Telomerase Research
in Lung Cancer]. ZHONGGUO FEI AI ZA ZHI = CHINESE JOURNAL OF LUNG CANCER 2021; 24:25-30. [PMID: 33478187 PMCID: PMC7849035 DOI: 10.3779/j.issn.1009-3419.2020.102.45] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
肺癌是世界范围内发病率和死亡率较高的恶性肿瘤之一。端粒和端粒酶与肺癌的发生发展密切相关。虽然端粒酶可能不是导致细胞癌变的直接原因,但在维持端粒长度和肿瘤生长方面起到关键作用。包括肺癌在内的大部分肿瘤端粒长度缩短。端粒长度的变化与肺癌发生风险相关,并可能成为肺癌的治疗靶标和预测指标。针对端粒和端粒酶信号通路的靶向治疗药物正在探索中,以端粒酶抑制剂为代表的小分子药物有希望应用于肺癌的临床治疗中。但是,人们对于端粒和端粒酶的研究还远远不够,端粒长度维持的旁路作用机制可能是下一步需要深入研究的方向。
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Affiliation(s)
- Sen Han
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Peking University Cancer Hospital & Institute, Beijing 100142, China
| | - Xu Ma
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Peking University Cancer Hospital & Institute, Beijing 100142, China
| | - Jian Fang
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Peking University Cancer Hospital & Institute, Beijing 100142, China
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5
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Fundamental insights into the interaction between telomerase/TERT and intracellular signaling pathways. Biochimie 2020; 181:12-24. [PMID: 33232793 DOI: 10.1016/j.biochi.2020.11.015] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 11/07/2020] [Accepted: 11/16/2020] [Indexed: 12/12/2022]
Abstract
Telomerase activity is critical for cancer cells to provide unrestricted proliferation and cellular immortality through maintaining telomeres. Telomerase enzymatic activity is regulatable at the level of DNA, mRNA, post translational modifications, cellular transport and enzyme assembly. More recent studies confirm the interaction of the telomerase with various intracellular signaling pathways including PI3K/AKT/mTOR, NF-κB and Wnt/β-catenin which mainly participating in inflammation, epithelial to mesenchymal transition (EMT) and tumor cell invasion and metastasis. Furthermore, hTERT protein has been detected in non-nuclear sites such as the mitochondria and cytoplasm in cells. Mitochondrial TERT indicates various non-telomere-related functions such as decreasing reactive oxygen species (ROS) generation, boosting the respiration rate, protecting mtDNA by direct binding, interacting with mitochondrial tRNAs and increasing mitochondrial membrane potential which can lead to higher chemoresistance rate in cancer cells during therapies. Understanding the molecular mechanisms of the TERT function and depended interactions in tumor cells can suggest novel therapeutic approaches. Hence, in this review we will explain the telomerase activity regulation in translational and post translational levels besides the established correlations with various cell signaling pathways with possible pathways for therapeutic targeting.
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6
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A Static Magnetic Field Inhibits the Migration and Telomerase Function of Mouse Breast Cancer Cells. BIOMED RESEARCH INTERNATIONAL 2020; 2020:7472618. [PMID: 32462015 PMCID: PMC7240788 DOI: 10.1155/2020/7472618] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 02/27/2020] [Accepted: 03/14/2020] [Indexed: 12/16/2022]
Abstract
Static magnetic field (SMF) has a potential as a cancer therapeutic modality due to its specific inhibitory effects on the proliferation of multiple cancer cells. However, the underlying mechanism remains unclear, and just a few studies have examined the effects of SMF on metastasis, an important concern in cancer treatment. In this study, we evaluated the effects of moderate SMF (~150 mT) on the proliferation and migration of 4T1 breast cancer cells. Our results showed that SMF treatment accelerated cell proliferation but inhibited cell migration. Further, SMF treatment shortened the telomere length, decreased telomerase activity, and inhibited the expression of the cancer-specific marker telomerase reverse transcriptase (TERT), which may be related to expression upregulation of e2f1, a transcription repressor of TERT and positive regulator of the mitotic cell cycle. Our results revealed that SMF repressed both, cell migration and telomerase function. The telomerase network is responsive to SMF and may be involved in SMF-mediated cancer-specific effects; moreover, it may function as a therapeutic target in magnetic therapy of cancers.
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Berei J, Eckburg A, Miliavski E, Anderson AD, Miller RJ, Dein J, Giuffre AM, Tang D, Deb S, Racherla KS, Patel M, Vela MS, Puri N. Potential Telomere-Related Pharmacological Targets. Curr Top Med Chem 2020; 20:458-484. [DOI: 10.2174/1568026620666200109114339] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 11/21/2019] [Accepted: 11/21/2019] [Indexed: 12/22/2022]
Abstract
Telomeres function as protective caps at the terminal portion of chromosomes, containing
non-coding nucleotide sequence repeats. As part of their protective function, telomeres preserve genomic
integrity and minimize chromosomal exposure, thus limiting DNA damage responses. With
continued mitotic divisions in normal cells, telomeres progressively shorten until they reach a threshold
at a point where they activate senescence or cell death pathways. However, the presence of the enzyme
telomerase can provide functional immortality to the cells that have reached or progressed past
senescence. In senescent cells that amass several oncogenic mutations, cancer formation can occur due
to genomic instability and the induction of telomerase activity. Telomerase has been found to be expressed
in over 85% of human tumors and is labeled as a near-universal marker for cancer. Due to this
feature being present in a majority of tumors but absent in most somatic cells, telomerase and telomeres
have become promising targets for the development of new and effective anticancer therapeutics.
In this review, we evaluate novel anticancer targets in development which aim to alter telomerase
or telomere function. Additionally, we analyze the progress that has been made, including preclinical
studies and clinical trials, with therapeutics directed at telomere-related targets. Furthermore, we review
the potential telomere-related therapeutics that are used in combination therapy with more traditional
cancer treatments. Throughout the review, topics related to medicinal chemistry are discussed,
including drug bioavailability and delivery, chemical structure-activity relationships of select therapies,
and the development of a unique telomere assay to analyze compounds affecting telomere elongation.
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Affiliation(s)
- Joseph Berei
- Department of Biomedical Sciences, University of Illinois College of Medicine at Rockford, Rockford, IL 61107, United States
| | - Adam Eckburg
- Department of Biomedical Sciences, University of Illinois College of Medicine at Rockford, Rockford, IL 61107, United States
| | - Edward Miliavski
- Department of Biomedical Sciences, University of Illinois College of Medicine at Rockford, Rockford, IL 61107, United States
| | - Austin D. Anderson
- Department of Biomedical Sciences, University of Illinois College of Medicine at Rockford, Rockford, IL 61107, United States
| | - Rachel J. Miller
- Department of Biomedical Sciences, University of Illinois College of Medicine at Rockford, Rockford, IL 61107, United States
| | - Joshua Dein
- Department of Biomedical Sciences, University of Illinois College of Medicine at Rockford, Rockford, IL 61107, United States
| | - Allison M. Giuffre
- Department of Biomedical Sciences, University of Illinois College of Medicine at Rockford, Rockford, IL 61107, United States
| | - Diana Tang
- Department of Biomedical Sciences, University of Illinois College of Medicine at Rockford, Rockford, IL 61107, United States
| | - Shreya Deb
- Department of Biomedical Sciences, University of Illinois College of Medicine at Rockford, Rockford, IL 61107, United States
| | - Kavya Sri Racherla
- Department of Biomedical Sciences, University of Illinois College of Medicine at Rockford, Rockford, IL 61107, United States
| | - Meet Patel
- Department of Biomedical Sciences, University of Illinois College of Medicine at Rockford, Rockford, IL 61107, United States
| | - Monica Saravana Vela
- Department of Biomedical Sciences, University of Illinois College of Medicine at Rockford, Rockford, IL 61107, United States
| | - Neelu Puri
- Department of Biomedical Sciences, University of Illinois College of Medicine at Rockford, Rockford, IL 61107, United States
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8
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Binding of BRACO19 to a Telomeric G-Quadruplex DNA Probed by All-Atom Molecular Dynamics Simulations with Explicit Solvent. Molecules 2019; 24:molecules24061010. [PMID: 30871220 PMCID: PMC6471034 DOI: 10.3390/molecules24061010] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Revised: 03/01/2019] [Accepted: 03/09/2019] [Indexed: 11/30/2022] Open
Abstract
Although BRACO19 is a potent G-quadruplex binder, its potential for clinical usage is hindered by its low selectivity towards DNA G-quadruplex over duplex. High-resolution structures of BRACO19 in complex with neither single-stranded telomeric DNA G-quadruplexes nor B-DNA duplex are available. In this study, the binding pathway of BRACO19 was probed by 27.5 µs molecular dynamics binding simulations with a free ligand (BRACO19) to a DNA duplex and three different topological folds of the human telomeric DNA G-quadruplex (parallel, anti-parallel and hybrid). The most stable binding modes were identified as end stacking and groove binding for the DNA G-quadruplexes and duplex, respectively. Among the three G-quadruplex topologies, the MM-GBSA binding energy analysis suggested that BRACO19′s binding to the parallel scaffold was most energetically favorable. The two lines of conflicting evidence plus our binding energy data suggest conformation-selection mechanism: the relative population shift of three scaffolds upon BRACO19 binding (i.e., an increase of population of parallel scaffold, a decrease of populations of antiparallel and/or hybrid scaffold). This hypothesis appears to be consistent with the fact that BRACO19 was specifically designed based on the structural requirements of the parallel scaffold and has since proven effective against a variety of cancer cell lines as well as toward a number of scaffolds. In addition, this binding mode is only slightly more favorable than BRACO19s binding to the duplex, explaining the low binding selectivity of BRACO19 to G-quadruplexes over duplex DNA. Our detailed analysis suggests that BRACO19′s groove binding mode may not be stable enough to maintain a prolonged binding event and that the groove binding mode may function as an intermediate state preceding a more energetically favorable end stacking pose; base flipping played an important role in enhancing binding interactions, an integral feature of an induced fit binding mechanism.
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9
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Sullivan HJ, Readmond C, Radicella C, Persad V, Fasano TJ, Wu C. Binding of Telomestatin, TMPyP4, BSU6037, and BRACO19 to a Telomeric G-Quadruplex-Duplex Hybrid Probed by All-Atom Molecular Dynamics Simulations with Explicit Solvent. ACS OMEGA 2018; 3:14788-14806. [PMID: 30555989 PMCID: PMC6289566 DOI: 10.1021/acsomega.8b01574] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Accepted: 09/11/2018] [Indexed: 06/09/2023]
Abstract
A promising anticancer therapeutic strategy is the stabilization of telomeric G-quadruplexes using G-quadruplex-binding small molecules. Although many G-quadruplex-specific ligands have been developed, their low potency and selectivity to G-quadruplexes over duplex remains unsolved. Recently, a crystal structure of a telomeric 3' quadruplex-duplex hybrid was reported and the quadruplex-duplex interface was suggested to a good target to address the issues. However, there are no high-resolution complex structures reported for G-quadruplex ligands except for a docked BSU6037. In this study, molecular dynamic (MD) binding simulations with a free ligand were used to study binding poses and dynamics of four representative ligands: telomestatin, TMPyP4, BSU6037, and BRACO19. The MD data showed that BSU6037 was able to fully intercalate into the interface whereas TMPyP4 and BRACO19 could only maintain partial intercalation into the interface and telomestatin only binds at the quadruplex and duplex ends. Both linear ligands, BSU6037 and BRACO19, were able to interact with the interface, yet they were not selective over duplex DNA. The DNA geometry, binding modes, and binding pathways were systematically characterized, and the binding energy was calculated and compared for each system. The interaction of the ligands to the interface was by the means of an induced-fit binding mechanism rather than a lock-key mechanism, consisting of the DNA unfolding at the interface to allow entrance of the drug and then the refolding and repacking of the DNA and the ligand to further stabilize the G-quadruplex. On the basis of the findings in this study, modifications were suggested to optimize the interface binding for TMPyp4 and telomestatin.
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Affiliation(s)
- Holli-Joi Sullivan
- Chemistry
& Biochemistry and Department of Molecular & Cellular Biosciences, College of Science and Mathematics, Rowan University, Glassboro, New Jersey 08028, United States
| | - Carolyn Readmond
- Chemistry
& Biochemistry and Department of Molecular & Cellular Biosciences, College of Science and Mathematics, Rowan University, Glassboro, New Jersey 08028, United States
| | - Christina Radicella
- Chemistry
& Biochemistry and Department of Molecular & Cellular Biosciences, College of Science and Mathematics, Rowan University, Glassboro, New Jersey 08028, United States
| | - Victoria Persad
- Chemistry
& Biochemistry and Department of Molecular & Cellular Biosciences, College of Science and Mathematics, Rowan University, Glassboro, New Jersey 08028, United States
| | - Thomas J. Fasano
- Chemistry
& Biochemistry and Department of Molecular & Cellular Biosciences, College of Science and Mathematics, Rowan University, Glassboro, New Jersey 08028, United States
| | - Chun Wu
- Chemistry
& Biochemistry and Department of Molecular & Cellular Biosciences, College of Science and Mathematics, Rowan University, Glassboro, New Jersey 08028, United States
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10
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Chhabra G, Wojdyla L, Frakes M, Schrank Z, Leviskas B, Ivancich M, Vinay P, Ganapathy R, Ramirez BE, Puri N. Mechanism of Action of G-Quadruplex-Forming Oligonucleotide Homologous to the Telomere Overhang in Melanoma. J Invest Dermatol 2017; 138:903-910. [PMID: 29203363 DOI: 10.1016/j.jid.2017.11.021] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2016] [Revised: 11/09/2017] [Accepted: 11/13/2017] [Indexed: 12/19/2022]
Abstract
T-oligo, a guanine-rich oligonucleotide homologous to the 3'-telomeric overhang of telomeres, elicits potent DNA-damage responses in melanoma cells; however, its mechanism of action is largely unknown. Guanine-rich oligonucleotides can form G-quadruplexes (G4), which are stabilized by the hydrogen bonding of guanine residues. In this study, we confirmed the G4-forming capabilities of T-oligo using nondenaturing PAGE, nuclear magnetic resonance, and immunofluorescence. Using an anti-G-quadruplex antibody, we showed that T-oligo can form G4 in the nuclei of melanoma cells. Furthermore, using DNase I in a nuclease degradation assay, G4-T-oligo was found to be more stable than single-stranded T-oligo. G4-T-oligo had decreased antiproliferative effects compared with single-stranded T-oligo. However, G4-T-oligo has similar cellular uptake as single-stranded T-oligo, as shown by FACS analysis. Inhibition of JNK, which causes DNA damage-induced apoptosis, partially reversed the antiproliferative activity of T-oligo. T-oligo also inhibited mRNA expression of human telomerase reverse transcriptase, a catalytic subunit of telomerase that was reversed by JNK inhibition. Furthermore, two shelterin complex proteins TRF2/POT1 were found to be up-regulated and bound by T-oligo, suggesting that T-oligo may mediate dissociation of these proteins from the telomere overhang. These studies show that T-oligo can form a G-quadruplex and that the antitumor effects of T-oligo may be mediated through POT1/TRF2 and via human telomerase reverse transcriptase inhibition through JNK activation.
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Affiliation(s)
- Gagan Chhabra
- University of Illinois College of Medicine at Rockford, Rockford, Illinois, USA
| | - Luke Wojdyla
- University of Illinois College of Medicine at Rockford, Rockford, Illinois, USA
| | - Mark Frakes
- University of Illinois College of Medicine at Rockford, Rockford, Illinois, USA
| | - Zachary Schrank
- University of Illinois College of Medicine at Rockford, Rockford, Illinois, USA
| | - Brandon Leviskas
- University of Illinois College of Medicine at Rockford, Rockford, Illinois, USA
| | - Marko Ivancich
- University of Illinois College of Medicine at Rockford, Rockford, Illinois, USA
| | - Pooja Vinay
- University of Illinois College of Medicine at Rockford, Rockford, Illinois, USA
| | | | - Benjamin E Ramirez
- Center for Structural Biology, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Neelu Puri
- University of Illinois College of Medicine at Rockford, Rockford, Illinois, USA.
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11
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Machireddy B, Kalra G, Jonnalagadda S, Ramanujachary K, Wu C. Probing the Binding Pathway of BRACO19 to a Parallel-Stranded Human Telomeric G-Quadruplex Using Molecular Dynamics Binding Simulation with AMBER DNA OL15 and Ligand GAFF2 Force Fields. J Chem Inf Model 2017; 57:2846-2864. [PMID: 29028340 DOI: 10.1021/acs.jcim.7b00287] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Human telomeric DNA G-quadruplex has been identified as a good therapeutic target in cancer treatment. G-quadruplex-specific ligands that stabilize the G-quadruplex have great potential to be developed as anticancer agents. Two crystal structures (an apo form of parallel stranded human telomeric G-quadruplex and its holo form in complex with BRACO19, a potent G-quadruplex ligand) have been solved, yet the binding mechanism and pathway remain elusive. In this study, we simulated the binding of a free BRACO19 molecule to the apo form of the G-quadruplex using the latest AMBER DNA (OL15) and ligand (GAFF2) force fields. Three binding modes have been identified: top stacking, bottom intercalation, and groove binding. Bottom intercalation (51% of the population) resembles the bottom binding pose in the complex crystal structure very well. The groove binding mode is less stable than the bottom binding mode and is likely to be an intermediate state leading to the bottom binding mode. A flip-insertion mechanism was observed in the bottom intercalation mode, during which flipping of the bases outward makes space for ligand insertion, after which the bases flip back to increase the stability of the complex. In addition to reproducing the base-flipping behavior for some loop residues upon ligand binding, the direct alignment type of the ATAT-tetrad was observed in our simulations for the first time. These successes provide initial support for using this combination of the OL15 and GAFF2 force fields to study quadruplex-ligand interactions.
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Affiliation(s)
- Babitha Machireddy
- College of Science and Mathematics, Rowan University , Glassboro, New Jersey 08028, United States
| | - Gurmannat Kalra
- College of Science and Mathematics, Rowan University , Glassboro, New Jersey 08028, United States
| | - Subash Jonnalagadda
- College of Science and Mathematics, Rowan University , Glassboro, New Jersey 08028, United States
| | - Kandalam Ramanujachary
- College of Science and Mathematics, Rowan University , Glassboro, New Jersey 08028, United States
| | - Chun Wu
- College of Science and Mathematics, Rowan University , Glassboro, New Jersey 08028, United States
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12
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Treating Cancer by Targeting Telomeres and Telomerase. Antioxidants (Basel) 2017; 6:antiox6010015. [PMID: 28218725 PMCID: PMC5384178 DOI: 10.3390/antiox6010015] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 02/15/2017] [Accepted: 02/16/2017] [Indexed: 12/22/2022] Open
Abstract
Telomerase is expressed in more than 85% of cancer cells. Tumor cells with metastatic potential may have a high telomerase activity, allowing cells to escape from the inhibition of cell proliferation due to shortened telomeres. Human telomerase primarily consists of two main components: hTERT, a catalytic subunit, and hTR, an RNA template whose sequence is complimentary to the telomeric 5′-dTTAGGG-3′ repeat. In humans, telomerase activity is typically restricted to renewing tissues, such as germ cells and stem cells, and is generally absent in normal cells. While hTR is constitutively expressed in most tissue types, hTERT expression levels are low enough that telomere length cannot be maintained, which sets a proliferative lifespan on normal cells. However, in the majority of cancers, telomerase maintains stable telomere length, thereby conferring cell immortality. Levels of hTERT mRNA are directly related to telomerase activity, thereby making it a more suitable therapeutic target than hTR. Recent data suggests that stabilization of telomeric G-quadruplexes may act to indirectly inhibit telomerase action by blocking hTR binding. Telomeric DNA has the propensity to spontaneously form intramolecular G-quadruplexes, four-stranded DNA secondary structures that are stabilized by the stacking of guanine residues in a planar arrangement. The functional roles of telomeric G-quadruplexes are not completely understood, but recent evidence suggests that they can stall the replication fork during DNA synthesis and inhibit telomere replication by preventing telomerase and related proteins from binding to the telomere. Long-term treatment with G-quadruplex stabilizers induces a gradual reduction in the length of the G-rich 3’ end of the telomere without a reduction of the total telomere length, suggesting that telomerase activity is inhibited. However, inhibition of telomerase, either directly or indirectly, has shown only moderate success in cancer patients. Another promising approach of targeting the telomere is the use of guanine-rich oligonucleotides (GROs) homologous to the 3’ telomere overhang sequence (T-oligos). T-oligos, particularly a specific 11-base oligonucleotide (5’-dGTTAGGGTTAG-3’) called T11, have been shown to induce DNA damage responses (DDRs) such as senescence, apoptosis, and cell cycle arrest in numerous cancer cell types with minimal or no cytostatic effects in normal, non-transformed cells. As a result, T-oligos and other GROs are being investigated as prospective anticancer therapeutics. Interestingly, the DDRs induced by T-oligos in cancer cells are similar to the effects seen after progressive telomere degradation in normal cells. The loss of telomeres is an important tumor suppressor mechanism that is commonly absent in transformed malignant cells, and hence, T-oligos have garnered significant interest as a novel strategy to combat cancer. However, little is known about their mechanism of action. In this review, we discuss the current understanding of how T-oligos exert their antiproliferative effects in cancer cells and their role in inhibition of telomerase. We also discuss the current understanding of telomerase in cancer and various therapeutic targets related to the telomeres and telomerase.
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Chen Y, Zhang Y. Functional and mechanistic analysis of telomerase: An antitumor drug target. Pharmacol Ther 2016; 163:24-47. [DOI: 10.1016/j.pharmthera.2016.03.017] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 03/29/2016] [Indexed: 01/26/2023]
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Polettini J, Behnia F, Taylor BD, Saade GR, Taylor RN, Menon R. Telomere Fragment Induced Amnion Cell Senescence: A Contributor to Parturition? PLoS One 2015; 10:e0137188. [PMID: 26397719 PMCID: PMC4580414 DOI: 10.1371/journal.pone.0137188] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 08/13/2015] [Indexed: 01/08/2023] Open
Abstract
Oxidative stress (OS)-induced senescence of the amniochorion has been associated with parturition at term. We investigated whether telomere fragments shed into the amniotic fluid (AF) correlated with labor status and tested if exogenous telomere fragments (T-oligos) could induce human and murine amnion cell senescence. In a cross-sectional clinical study, AF telomere fragment concentrations quantitated by a validated real-time PCR assay were higher in women in labor at term compared to those not in labor. In vitro treatment of primary human amnion epithelial cells with 40 μM T-oligos ([TTAGGG]2) that mimic telomere fragments, activated p38MAPK, produced senescence-associated (SA) β-gal staining and increased interleukin (IL)-6 and IL-8 production compared to cells treated with complementary DNA sequences (Cont-oligos, [AATCCC]2). T-oligos injected into the uteri of pregnant CD1 mice on day 14 of gestation, led to increased p38MAPK, SA-β-gal (SA β-gal) staining in murine amniotic sacs and higher AF IL-8 levels on day 18, compared to saline treated controls. In summary, term labor AF samples had higher telomere fragments than term not in labor AF. In vitro and in situ telomere fragments increased human and murine amnion p38MAPK, senescence and inflammatory cytokines. We propose that telomere fragments released from senescent fetal cells are indicative of fetal cell aging. Based on our data, these telomere fragments cause oxidative stress associated damages to the term amniotic sac and force them to release other DAMPS, which, in turn, provide a sterile immune response that may be one of the many inflammatory signals required to initiate parturition at term.
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Affiliation(s)
- Jossimara Polettini
- Division of Maternal-Fetal Medicine and Perinatal Research, Department of Obstetrics and Gynecology, The University of Texas Medical Branch at Galveston, Galveston, Texas, United States of America
- Department of Pathology, Botucatu Medical School, UNESP–Univ. Estadual Paulista, Botucatu, Sao Paulo, Brazil
| | - Faranak Behnia
- Division of Maternal-Fetal Medicine and Perinatal Research, Department of Obstetrics and Gynecology, The University of Texas Medical Branch at Galveston, Galveston, Texas, United States of America
| | - Brandie D. Taylor
- Department of Epidemiology & Biostatistics, Texas A&M University System Health Science Center, College Station, Texas, United States of America
| | - George R. Saade
- Division of Maternal-Fetal Medicine and Perinatal Research, Department of Obstetrics and Gynecology, The University of Texas Medical Branch at Galveston, Galveston, Texas, United States of America
| | - Robert N. Taylor
- Department of Obstetrics and Gynecology, Wake Forest University, Winston Salem, North Carolina, United States of America
| | - Ramkumar Menon
- Division of Maternal-Fetal Medicine and Perinatal Research, Department of Obstetrics and Gynecology, The University of Texas Medical Branch at Galveston, Galveston, Texas, United States of America
- * E-mail:
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Picariello L, Grappone C, Polvani S, Galli A. Telomerase activity: An attractive target for cancer therapeutics. World J Pharmacol 2014; 3:86-96. [DOI: 10.5497/wjp.v3.i4.86] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Revised: 10/01/2014] [Accepted: 10/29/2014] [Indexed: 02/06/2023] Open
Abstract
Telomeres are non-coding tandem repeats of 1000-2000 TTAGGG nucleotide DNA sequences on the 3’ termini of human chromosomes where they serve as protective “caps” from degradation and loss of genes. The “cap” at the end of chromosome required to protect its integrity is a 150-200 nucleotide-long single stranded G-rich 3’ overhang that forms two higher order structures, a T-loop with Sheltering complex, or a G-quadruplex complex. Telomerase is a human ribonucleoprotein reverse transcriptase that continually added single stranded TTAGGG DNA sequences onto the single strand 3’ of telomere in the 5’ to 3’ direction. Telomerase activity is detected in male germ line cells, proliferative cells of renewal tissues, some adult pluripotent stem cells, embryonic cells, but in most somatic cells is not detected. Re-expression or up-regulation of telomerase in tumours cells is considered as a critical step in cell tumorigenesis and telomerase is widely considered as a tumour marker and a target for anticancer drugs. Different approaches have been used in anticancer therapeutics targeting telomerase. Telomerase inhibitors can block directly Human TElomerase Reverse Transcriptase (hTERT) or Human TElomerase RNA telomerase subunits activity, or G-quadruplex and Sheltering complex components, shortening telomeres and inhibiting cell proliferation. Telomerase can become an immune target and GV1001, Vx-001, I540 are the most widespread vaccines used with encouraging results. Another method is to use hTERT promoter to drive suicide gene expression or to control a lytic virus replication. Recently telomerase activity was used to activate pro-drugs such as Acycloguanosyl 5’-thymidyltriphosphate, a synthetic ACV-derived molecule when it is activated by telomerase it does not require any virus or host active immune response to induce suicide gene therapy. Advantage of all these therapies is that target only neoplastic cells without any effects in normal cells, avoiding toxicity and adverse effects of the current chemotherapy. However, as not all the approaches are equally efficient, further studies will be necessary.
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Taka T, Changtam C, Thaichana P, Kaewtunjai N, Suksamrarn A, Lee TR, Tuntiwechapikul W. Curcuminoid derivatives enhance telomerase activity in an in vitro TRAP assay. Bioorg Med Chem Lett 2014; 24:5242-6. [PMID: 25305686 DOI: 10.1016/j.bmcl.2014.09.059] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2014] [Revised: 09/01/2014] [Accepted: 09/20/2014] [Indexed: 10/24/2022]
Abstract
The length of telomeres controls the life span of eukaryotic cells. Telomerase maintains the length of telomeres in certain eukaryotic cells, such as germline cells and stem cells, and allows these cells to evade replicative senescence. Here, we report for the first time a number of curcuminoid derivatives that enhance telomerase activity in an in vitro TRAP assay. A preliminary analysis of structure-activity relationships found that the minimal requirement for this enhanced telomerase activity is a curcuminoid core with at least one n-pentylpyridine side chain, while curcuminoids with two such side chains exhibit even greater activity. The finding here might lead to a new class of telomerase activators that act directly or indirectly on telomerase, rather than through the reactivation of the telomerase reverse transcriptase (TERT) gene associated with other telomerase activators found in the literature.
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Affiliation(s)
- Thanachai Taka
- Department of Biochemistry, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Chatchawan Changtam
- Division of Physical Science, Faculty of Science and Technology, Huachiew Chalermprakiet University, Samutprakarn 10540, Thailand
| | - Pak Thaichana
- Department of Biochemistry, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Navakoon Kaewtunjai
- Department of Biochemistry, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Apichart Suksamrarn
- Department of Chemistry, Faculty of Science, Ramkhamhaeng University, Bangkok 10240, Thailand
| | - T Randall Lee
- Department of Chemistry and the Texas Center for Superconductivity, University of Houston, Houston, TX 77204-5003, USA
| | - Wirote Tuntiwechapikul
- Department of Biochemistry, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand
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T-oligo as an anticancer agent in colorectal cancer. Biochem Biophys Res Commun 2014; 446:596-601. [PMID: 24632202 DOI: 10.1016/j.bbrc.2014.03.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Accepted: 03/04/2014] [Indexed: 11/22/2022]
Abstract
In the United States, there will be an estimated 96,830 new cases of colorectal cancer (CRC) and 50,310 deaths in 2014. CRC is often detected at late stages of the disease, at which point there is no effective chemotherapy. Thus, there is an urgent need for effective novel therapies that have minimal effects on normal cells. T-oligo, an oligonucleotide homologous to the 3'-telomere overhang, induces potent DNA damage responses in multiple malignant cell types, however, its efficacy in CRC has not been studied. This is the first investigation demonstrating T-oligo-induced anticancer effects in two CRC cell lines, HT-29 and LoVo, which are highly resistant to conventional chemotherapies. In this investigation, we show that T-oligo may mediate its DNA damage responses through the p53/p73 pathway, thereby inhibiting cellular proliferation and inducing apoptosis or senescence. Additionally, upregulation of downstream DNA damage response proteins, including E2F1, p53 or p73, was observed. In LoVo cells, T-oligo induced senescence, decreased clonogenicity, and increased expression of senescence associated proteins p21, p27, and p53. In addition, downregulation of POT1 and TRF2, two components of the shelterin protein complex which protects telomeric ends, was observed. Moreover, we studied the antiproliferative effects of T-oligo in combination with an EGFR tyrosine kinase inhibitor, Gefitinib, which resulted in an additive inhibitory effect on cellular proliferation. Collectively, these data provide evidence that T-oligo alone, or in combination with other molecularly targeted therapies, has potential as an anti-cancer agent in CRC.
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Pitman RT, Wojdyla L, Puri N. Mechanism of DNA damage responses induced by exposure to an oligonucleotide homologous to the telomere overhang in melanoma. Oncotarget 2014; 4:761-71. [PMID: 23800953 PMCID: PMC3742836 DOI: 10.18632/oncotarget.1047] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
T-oligo, an 11-base oligonucleotide homologous to the 3'-telomeric overhang, is a novel, potent therapeutic modality in melanoma and multiple other tumor types. T-oligo is proposed to function in a manner similar to experimental disruption of the telomere overhang and induces DNA damage responses including apoptosis, differentiation and senescence. However, important components involved in T-oligo induced responses are not defined, particularly the role of p53, TRF1 and TRF2 in mediating the T-oligo induced responses. In MU, PM-WK, and MM-MC melanoma cells, exposure to T-oligo upregulates p53 expression and phosphorylation, resulting in cellular differentiation and activation of a caspase-mediated apoptotic cascade. However, siRNA-mediated knockdown of p53 completely blocks T-oligo induced differentiation and significantly decreases apoptosis, suggesting that p53 is an important mediator of T-oligo induced responses. In addition, we characterized the roles of telomere binding proteins, TRF1, TRF2, and tankyrase-1, in T-oligo induced damage responses. We demonstrate that tankyrase-1 activity is required for initiation of T-oligo induced damage responses including p53 phosphorylation and reduction of cellular proliferation. These results highlight TRF1, TRF2, tankyrase-1 and p53 as important elements in T-oligo mediated responses and suggest new avenues for research into T-oligo's mechanism of action.
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Affiliation(s)
- Ryan T Pitman
- Department of Biomedical Sciences, University of Illinois College of Medicine, Rockford, Illinois, USA
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Mulnix RE, Pitman RT, Retzer A, Bertram C, Arasi K, Crees Z, Girard J, Uppada SB, Stone AL, Puri N. hnRNP C1/C2 and Pur-beta proteins mediate induction of senescence by oligonucleotides homologous to the telomere overhang. Onco Targets Ther 2013; 7:23-32. [PMID: 24379680 PMCID: PMC3872271 DOI: 10.2147/ott.s54575] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Background Experimental disruption of the telomere overhang induces a potent DNA damage response and is the target of newly emerging cancer therapeutics. Introduction of T-oligo, an eleven-base oligonucleotide homologous to the 3′-telomeric overhang, mimics telomere disruption and induces DNA damage responses through activation of p53, p73, p95/Nbs1, E2F1, pRb, and other DNA damage response proteins. ATM (ataxia telangiectasia mutated) was once thought to be the primary driver of T-oligo-induced DNA damage responses; however, recent experiments have highlighted other key proteins that may also play a significant role. Methods To identify proteins associated with T-oligo, MM-AN cells were treated with biotinylated T-oligo or complementary oligonucleotide, cell lysates were run on SDS-PAGE (sodium dodecyl sulfate polyacrylamide gel electrophoresis), and the protein bands observed after treatment of cells with T-oligo or complementary oligonucleotide were analyzed using mass spectrometry. To study the effect of T-oligo on expression of hnRNP C1/C2 (heterogeneous nuclear ribonucleoprotein C1 and C2) and purine-rich element binding proteins (Pur proteins), cells were treated with T-oligo, and immunoblotting experiments were performed. To determine their role in senescence, cells were treated with shRNA (short hairpin ribonucleic acid) against these proteins, and senescence was studied using the senescence associated beta-galactosidase assay. Results Using mass spectrometry, RNA-binding hnRNP C1/C2 and DNA-binding Pur proteins were found to associate with T-oligo. hnRNP C1/C2 exhibited increased expression (3.6–12.0-fold) in non-small-cell lung cancer (NSCLC) and in melanoma cells (4.5–5.2-fold), and Pur proteins exhibited increased expression of 2.2-fold in NSCLC and 2.0-fold in melanoma cells after T-oligo treatment. Experimental knockdown of hnRNP C1/C2 and Pur-beta completely abrogated T-oligo induced senescence in both MU melanoma and H358 NSCLC cells. Additionally, knockdown of Pur-beta prevented T-oligo-induced phosphorylation of p53, hypophosphorylation of pRb, and upregulation of E2F1, p21, and p53. Conclusion These novel findings highlight proteins essential to T-oligo’s anticancer effects that may be of interest in telomere biology and cancer therapeutics.
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Affiliation(s)
- Richard E Mulnix
- Department of Biomedical Sciences, University of Illinois at Chicago, Rockford, IL, USA
| | - Ryan T Pitman
- Department of Biomedical Sciences, University of Illinois at Chicago, Rockford, IL, USA
| | - Allison Retzer
- College of Medicine, University of Illinois at Chicago, Rockford, IL, USA
| | - Ceyda Bertram
- Department of Biomedical Sciences, University of Illinois at Chicago, Rockford, IL, USA
| | - Kavin Arasi
- College of Medicine, University of Illinois at Chicago, Rockford, IL, USA
| | - Zachary Crees
- College of Medicine, University of Illinois at Chicago, Rockford, IL, USA
| | - Jennifer Girard
- College of Medicine, University of Illinois at Chicago, Rockford, IL, USA
| | | | - Amanda L Stone
- Department of Biomedical Sciences, University of Illinois at Chicago, Rockford, IL, USA
| | - Neelu Puri
- Department of Biomedical Sciences, University of Illinois at Chicago, Rockford, IL, USA
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Penchovsky R, Kostova GT. Computational selection and experimental validation of allosteric ribozymes that sense a specific sequence of human telomerase reverse transcriptase mRNAs as universal anticancer therapy agents. Nucleic Acid Ther 2013; 23:408-17. [PMID: 24206267 PMCID: PMC3868306 DOI: 10.1089/nat.2013.0446] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Accepted: 10/07/2013] [Indexed: 12/19/2022] Open
Abstract
High expression levels of telomerase reverse transcriptase messenger RNAs in differentiated cells can be used as a common marker for cancer development. In this paper, we describe a novel computational method for selection of allosteric ribozymes that sense a specific sequence of human telomerase reverse transcriptase mRNAs. The in silico selection employed is based on computing secondary structures of RNA using the partition function in combination with a random search algorithm. We selected one of the ribozymes for experimental validation. The obtained results demonstrate that the tested ribozyme has a high-speed (∼1.8 per minute) of self-cleavage and is very selective. It can distinguish well between perfectly matching effector and the closest expressed RNA sequence in the human cell with 10 mismatches, with a ∼300-fold difference under physiologically relevant conditions. The presented algorithm is universal since the allosteric ribozymes can be designed to sense any specific RNA or DNA sequence of interest. Such designer ribozymes may be used for monitoring the expression of mRNAs in the cell and for developing novel anticancer gene therapies.
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Affiliation(s)
- Robert Penchovsky
- Department of Genetics, Faculty of Biology, Sofia University St. Kliment Ohridski , Sofia, Bulgaria
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21
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Shalaby T, Fiaschetti G, Nagasawa K, Shin-ya K, Baumgartner M, Grotzer M. G-quadruplexes as potential therapeutic targets for embryonal tumors. Molecules 2013; 18:12500-37. [PMID: 24152672 PMCID: PMC6269990 DOI: 10.3390/molecules181012500] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 09/18/2013] [Accepted: 09/25/2013] [Indexed: 12/27/2022] Open
Abstract
Embryonal tumors include a heterogeneous group of highly malignant neoplasms that primarily affect infants and children and are characterized by a high rate of mortality and treatment-related morbidity, hence improved therapies are clearly needed. G-quadruplexes are special secondary structures adopted in guanine (G)-rich DNA sequences that are often present in biologically important regions, e.g. at the end of telomeres and in the regulatory regions of oncogenes such as MYC. Owing to the significant roles that both telomeres and MYC play in cancer cell biology, G-quadruplexes have been viewed as emerging therapeutic targets in oncology and as tools for novel anticancer drug design. Several compounds that target these structures have shown promising anticancer activity in tumor xenograft models and some of them have entered Phase II clinical trials. In this review we examine approaches to DNA targeted cancer therapy, summarize the recent developments of G-quadruplex ligands as anticancer drugs and speculate on the future direction of such structures as a potential novel therapeutic strategy for embryonal tumors of the nervous system.
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Affiliation(s)
- Tarek Shalaby
- Division of Oncology, University Children's Hospital of Zurich, Zurich 8032, Switzerland.
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22
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Puri N, Pitman RT, Mulnix RE, Erickson T, Iness AN, Vitali C, Zhao Y, Salgia R. Non-small cell lung cancer is susceptible to induction of DNA damage responses and inhibition of angiogenesis by telomere overhang oligonucleotides. Cancer Lett 2013; 343:14-23. [PMID: 24041868 DOI: 10.1016/j.canlet.2013.09.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Revised: 08/15/2013] [Accepted: 09/08/2013] [Indexed: 10/26/2022]
Abstract
Exposure of the telomere overhang acts as a DNA damage signal, and exogenous administration of an 11-base oligonucleotide homologous to the 3'-telomere overhang sequence (T-oligo) mimics the effects of overhang exposure by inducing senescence and cell death in non-small cell lung cancer (NSCLC) cells, but not in normal bronchial epithelial cells. T-oligo-induced decrease in cellular proliferation in NSCLC is likely directed through both p53 and its homolog, p73, with subsequent induction of senescence and expression of senescence-associated proteins, p21, p33(ING), and p27(Kip1) both in vivo and in vitro. Additionally, T-oligo decreases tumor size and inhibits angiogenesis through decreased VEGF signaling and increased TSP-1 expression.
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Affiliation(s)
- Neelu Puri
- Department of Biomedical Sciences, University of Illinois College of Medicine, Rockford, IL, United States.
| | - Ryan T Pitman
- Department of Biomedical Sciences, University of Illinois College of Medicine, Rockford, IL, United States
| | - Richard E Mulnix
- Department of Biomedical Sciences, University of Illinois College of Medicine, Rockford, IL, United States
| | - Terrianne Erickson
- Department of Biomedical Sciences, University of Illinois College of Medicine, Rockford, IL, United States
| | - Audra N Iness
- Department of Biomedical Sciences, University of Illinois College of Medicine, Rockford, IL, United States
| | - Connie Vitali
- Department of Pathology, University of Illinois College of Medicine, Rockford, IL, United States
| | - Yutong Zhao
- Department of Medicine, Division of Pulmonary, Allergy, Critical Care, University of Pittsburgh, Pittsburgh, PA, United States
| | - Ravi Salgia
- Department of Medicine, Section of Hematology/Oncology, University of Chicago, Chicago, IL, United States
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Lee J, Sammond DW, Fiorini Z, Saludes JP, Resch MG, Hao B, Wang W, Yin H, Liu X. Computationally designed peptide inhibitors of the ubiquitin E3 ligase SCF(Fbx4). Chembiochem 2013; 14:445-51. [PMID: 23401343 DOI: 10.1002/cbic.201200777] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Indexed: 11/07/2022]
Abstract
A structure-based computational approach was used to rationally design peptide inhibitors that can target an E3 ligase (SCF(Fbx4) )-substrate (TRF1) interface and subsequent ubiquitylation. Characterization of the inhibitors demonstrates that our sequence-optimization protocol results in an increase in peptide-TRF1 affinity without compromising peptide-protein specificity.
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Affiliation(s)
- Junglim Lee
- Department of Chemistry and Biochemistry, 596 UCB, University of Colorado, JSCBB 3415 Colorado Avenue, Boulder, CO 80309-0215, USA
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Ruden M, Puri N. Novel anticancer therapeutics targeting telomerase. Cancer Treat Rev 2012; 39:444-56. [PMID: 22841437 DOI: 10.1016/j.ctrv.2012.06.007] [Citation(s) in RCA: 222] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Revised: 06/14/2012] [Accepted: 06/19/2012] [Indexed: 12/12/2022]
Abstract
Telomeres are protective caps at the ends of human chromosomes. Telomeres shorten with each successive cell division in normal human cells whereas, in tumors, they are continuously elongated by human telomerase reverse transcriptase (hTERT). Telomerase is overexpressed in 80-95% of cancers and is present in very low levels or is almost undetectable in normal cells. Because telomerase plays a pivotal role in cancer cell growth it may serve as an ideal target for anticancer therapeutics. Inhibition of telomerase may lead to a decrease of telomere length resulting in cell senescence and apoptosis in telomerase positive tumors. Several strategies of telomerase inhibition are reviewed, including small molecule inhibitors, antisense oligonucleotides, immunotherapies and gene therapies, targeting the hTERT or the ribonucleoprotein subunit hTER. G-quadruplex stabilizers, tankyrase and HSP90 inhibitors targeting telomere and telomerase assembly, and T-oligo approach are also covered. Based on this review, the most promising current telomerase targeting therapeutics are the antisense oligonucleotide inhibitor GRN163L and immunotherapies that use dendritic cells (GRVAC1), hTERT peptide (GV1001) or cryptic peptides (Vx-001). Most of these agents have entered phase I and II clinical trials in patients with various tumors, and have shown good response rates as evidenced by a reduction in tumor cell growth, increased overall disease survival, disease stabilization in advanced staged tumors and complete/partial responses. Most therapeutics have shown to be more effective when used in combination with standard therapies, resulting in concomitant telomere shortening and tumor mass shrinkage, as well as preventing tumor relapse and resistance to single agent therapy.
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Affiliation(s)
- Maria Ruden
- Department of Biomedical Sciences, University of Illinois College of Medicine at Rockford, Rockford, IL 61107-1822, USA
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Chen Q, Wang X, Ru Y, Chen S, Gao S, Xing L, Mi J, Wang Y, Xiao Z, Feng X. Amplification of the telomerase RNA component gene in the process of human esophageal carcinogenesis. TOHOKU J EXP MED 2011; 224:99-104. [PMID: 21597243 DOI: 10.1620/tjem.224.99] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Amplification of the human telomerase RNA component (hTERC) gene occurs early in cervical cancer development. Telomerase, the product of the hTERC gene, plays an important role in tumor cell apoptosis and genomic stability. Given the numerous similarities between esophageal and cervical cancers, we hypothesized that hTERC gene amplification may also be related with esophageal cancer development. We therefore examined 189 tissue sections from 63 cases of esophageal cancer and preneoplastic lesions. hTERC gene amplification in the lesions was detected by interphase fluorescence in situ hybridization. Of the 189 tissue sections, 149 were successfully evaluated (40 samples were excluded because of inappropriately preparation) and were classified as normal (n=45), atypical hyperplasia I (n=27), atypical hyperplasia II/III (n=22), and squamous cell carcinomas (SCCs; the most common type of esophageal cancer) (n=55). hTERC gene expression was not detected in normal esophageal tissue, whereas its expression was detected in atypical hyperplasias I (25.9%), atypical hyperplasia II/III (54.5%), and SCCs (90.9%) (p<0.05). The average copy numbers of hTERC in atypical hyperplasias I and II/III, as well as SCCs were 2.19, 2.35, and 2.64, respectively. In particular, the numbers of abnormal nuclei in atypical hyperplasias II/III were significantly higher than those of in atypical hyperplasia I (p<0.05). The hTERC gene amplification was not related with patient gender, histological stage, lymph nodes metastasis, and SCC differentiation grade (p>0.05). All these findings suggest that hTERC gene amplification is associated with SCC development.
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Affiliation(s)
- Qiang Chen
- Department of Oncology, Cancer Institute, First Affiliated Hospital of Henan University of Science and Technology, Luoyang, PR China
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Sarkar S, Faller DV. T-oligos inhibit growth and induce apoptosis in human ovarian cancer cells. Oligonucleotides 2011; 21:47-53. [PMID: 21281128 DOI: 10.1089/oli.2010.0259] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Ovarian cancer remains a leading cause of death among women worldwide, and current treatment regimens for advanced disease are inadequate. Oligonucleotides with sequence homology to telomeres (called T-oligos) have been shown to mimic DNA damage responses in cells and induce cytotoxic effects in certain tumor cell lines. We studied the effects of 2 distinct 16 mer T-oligos in 4 human ovarian epithelial carcinoma cell lines. A T-oligo with perfect homology to the telomere overhang region demonstrated some cytotoxic activity in half of the cell lines. A G-rich T-oligo derivative showed more potency and broader cytotoxic activity in these lines than the parental T-oligo. Activation of apoptotic pathways in ovarian cancer cells by exposure to the T-oligo was demonstrated by multiple independent assays. T-oligo was shown to have additive, or more than additive, activity in combination with 2 different histone deacetylase drugs currently in clinical testing. T-oligos may therefore provide a new and tumor-targeted approach to ovarian cancers.
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Affiliation(s)
- Sibaji Sarkar
- Cancer Center, Boston University School of Medicine, Boston, Massachusetts, USA
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Linder J, Garner TP, Williams HEL, Searle MS, Moody CJ. Telomestatin: formal total synthesis and cation-mediated interaction of its seco-derivatives with G-quadruplexes. J Am Chem Soc 2010; 133:1044-51. [PMID: 21162526 DOI: 10.1021/ja109158k] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The structurally unique natural product telomestatin incorporates seven oxazole rings and one sulfur-containing thiazoline in a macrocyclic arrangement. The compound is a potent inhibitor of the enzyme telomerase and therefore provides a structural framework for developing new potential therapeutic agents for cancer. An efficient formal total synthesis of telomestatin is reported in which the key steps are the use of dirhodium(II)-catalyzed reactions of diazocarbonyl compounds to generate six oxazole rings, demonstrating the power of rhodium carbene methodology in organic chemical synthesis. CD spectroscopy establishes that seco-derivatives of telomestatin are potent stabilizers of G-quadruplex structures derived from the human telomeric repeat sequence. Mass spectrometry studies, confirmed by molecular dynamics simulations, provide the first evidence that high affinity binding to terminal G-tetrads in both 1:1 and 2:1 ligand complexes is mediated through the macrocycle coordinating a monovalent cation, with selectivity for the antiparallel structure.
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Affiliation(s)
- Jörg Linder
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
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Abstract
Telomeres and telomerase play essential roles in the regulation of the lifespan of human cells. While normal human somatic cells do not or only transiently express telomerase and therefore shorten their telomeres with each cell division, most human cancer cells typically express high levels of telomerase and show unlimited cell proliferation. High telomerase expression allows cells to proliferate and expand long-term and therefore supports tumor growth. Owing to the high expression and its role, telomerase has become an attractive diagnostic and therapeutic cancer target. Imetelstat (GRN163L) is a potent and specific telomerase inhibitor and so far the only drug of its class in clinical trials. Here, we report on the structure and the mechanism of action of imetelstat as well as about the preclinical and clinical data and future prospects using imetelstat in cancer therapy.
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Telomeres and telomerase as novel drug targets: reflections on the 2009 Nobel Prize in Physiology or Medicine. Eur J Clin Pharmacol 2009; 66:1-3. [DOI: 10.1007/s00228-009-0758-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2009] [Accepted: 10/29/2009] [Indexed: 01/29/2023]
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Telomere and telomerase as targets for cancer therapy. Appl Biochem Biotechnol 2009; 160:1460-72. [PMID: 19412578 DOI: 10.1007/s12010-009-8633-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2009] [Accepted: 03/31/2009] [Indexed: 02/08/2023]
Abstract
Telomere maintenance and telomerase reactivation is essential for the transformation of most human cancer cells. Telomere shortening to the threshold length, mutations of the telomere-associated proteins, and/or telomerase RNA lead to telomeric dysfunction and therefore genomic instability. Telomerase up-regulation in 85% of human cancer cells has become a hallmark of cancers, hence a promising target for anticancer therapy. In this review, we discuss the mechanism of cancer due to telomere dysfunction and the resulting biological effects, the control of telomerase activity, and the new developments in cancer therapies targeting telomere and telomerase.
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Folini M, Gandellini P, Zaffaroni N. Targeting the telosome: therapeutic implications. Biochim Biophys Acta Mol Basis Dis 2009; 1792:309-16. [PMID: 19419699 DOI: 10.1016/j.bbadis.2009.01.014] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2008] [Revised: 01/28/2009] [Accepted: 01/30/2009] [Indexed: 12/12/2022]
Abstract
Since telomere integrity is required to guarantee the unlimited replicative potential of cancer cells, telomerase, the enzyme responsible for telomere length maintenance in most human tumors, and lately also telomeres themselves have become extremely attractive targets for new anticancer interventions. At the current status of knowledge, it is still not possible to define the best therapeutic target between telomerase and telomeres. It is noteworthy that interfering with telomeres, through direct targeting of telomeric DNA or proteins involved in the telosome complex, could negatively affect the proliferative potential not only of tumors expressing telomerase activity but also of those that maintain their telomeres through alternative lengthening or still unknown mechanisms. This review presents the different therapeutic approaches proposed thus far and developed in preclinical tumor models and discusses the perspectives for their use in the clinical setting.
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Affiliation(s)
- Marco Folini
- Department of Experimental Oncology and Laboratories, Fondazione IRCCS Istituto Nazionale dei Tumori, Via Venezian 1, 20133 Milan, Italy
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Lane AN, Chaires JB, Gray RD, Trent JO. Stability and kinetics of G-quadruplex structures. Nucleic Acids Res 2008; 36:5482-515. [PMID: 18718931 PMCID: PMC2553573 DOI: 10.1093/nar/gkn517] [Citation(s) in RCA: 568] [Impact Index Per Article: 35.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2008] [Revised: 07/26/2008] [Accepted: 07/29/2008] [Indexed: 12/30/2022] Open
Abstract
In this review, we give an overview of recent literature on the structure and stability of unimolecular G-rich quadruplex structures that are relevant to drug design and for in vivo function. The unifying theme in this review is energetics. The thermodynamic stability of quadruplexes has not been studied in the same detail as DNA and RNA duplexes, and there are important differences in the balance of forces between these classes of folded oligonucleotides. We provide an overview of the principles of stability and where available the experimental data that report on these principles. Significant gaps in the literature have been identified, that should be filled by a systematic study of well-defined quadruplexes not only to provide the basic understanding of stability both for design purposes, but also as it relates to in vivo occurrence of quadruplexes. Techniques that are commonly applied to the determination of the structure, stability and folding are discussed in terms of information content and limitations. Quadruplex structures fold and unfold comparatively slowly, and DNA unwinding events associated with transcription and replication may be operating far from equilibrium. The kinetics of formation and resolution of quadruplexes, and methodologies are discussed in the context of stability and their possible biological occurrence.
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Affiliation(s)
- Andrew N Lane
- Structural Biology Program, JG Brown Cancer Center, University of Louisville, KY 40202, USA.
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