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Judasz E, Lisiak N, Kopczyński P, Taube M, Rubiś B. The Role of Telomerase in Breast Cancer's Response to Therapy. Int J Mol Sci 2022; 23:12844. [PMID: 36361634 PMCID: PMC9654063 DOI: 10.3390/ijms232112844] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 10/13/2022] [Accepted: 10/24/2022] [Indexed: 11/26/2023] Open
Abstract
Currently, breast cancer appears to be the most widespread cancer in the world and the most common cause of cancer deaths. This specific type of cancer affects women in both developed and developing countries. Prevention and early diagnosis are very important factors for good prognosis. A characteristic feature of cancer cells is the ability of unlimited cell division, which makes them immortal. Telomeres, which are shortened with each cell division in normal cells, are rebuilt in cancer cells by the enzyme telomerase, which is expressed in more than 85% of cancers (up to 100% of adenocarcinomas, including breast cancer). Telomerase may have different functions that are related to telomeres or unrelated. It has been shown that high activity of the enzyme in cancer cells is associated with poor cell sensitivity to therapies. Therefore, telomerase has become a potential target for cancer therapies. The low efficacy of therapies has resulted in the search for new combined and more effective therapeutic methods, including the involvement of telomerase inhibitors and telomerase-targeted immunotherapy.
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Affiliation(s)
- Eliza Judasz
- Department of Clinical Chemistry and Molecular Diagnostics, Poznan University of Medical Sciences, 60-806 Poznan, Poland
| | - Natalia Lisiak
- Department of Clinical Chemistry and Molecular Diagnostics, Poznan University of Medical Sciences, 60-806 Poznan, Poland
| | - Przemysław Kopczyński
- Centre for Orthodontic Mini-Implants at the Department and Clinic of Maxillofacial Orthopedics and Orthodontics, Poznan University of Medical Sciences, 60-812 Poznan, Poland
| | - Magdalena Taube
- Department of Clinical Chemistry and Molecular Diagnostics, Poznan University of Medical Sciences, 60-806 Poznan, Poland
| | - Błażej Rubiś
- Department of Clinical Chemistry and Molecular Diagnostics, Poznan University of Medical Sciences, 60-806 Poznan, Poland
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2
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Molinaro C, Martoriati A, Cailliau K. Proteins from the DNA Damage Response: Regulation, Dysfunction, and Anticancer Strategies. Cancers (Basel) 2021; 13:3819. [PMID: 34359720 PMCID: PMC8345162 DOI: 10.3390/cancers13153819] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 07/22/2021] [Accepted: 07/26/2021] [Indexed: 12/21/2022] Open
Abstract
Cells respond to genotoxic stress through a series of complex protein pathways called DNA damage response (DDR). These monitoring mechanisms ensure the maintenance and the transfer of a correct genome to daughter cells through a selection of DNA repair, cell cycle regulation, and programmed cell death processes. Canonical or non-canonical DDRs are highly organized and controlled to play crucial roles in genome stability and diversity. When altered or mutated, the proteins in these complex networks lead to many diseases that share common features, and to tumor formation. In recent years, technological advances have made it possible to benefit from the principles and mechanisms of DDR to target and eliminate cancer cells. These new types of treatments are adapted to the different types of tumor sensitivity and could benefit from a combination of therapies to ensure maximal efficiency.
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Affiliation(s)
| | | | - Katia Cailliau
- Univ. Lille, CNRS, UMR 8576-UGSF-Unité de Glycobiologie Structurale et Fonctionnelle, F-59000 Lille, France; (C.M.); (A.M.)
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3
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Eckburg A, Dein J, Berei J, Schrank Z, Puri N. Oligonucleotides and microRNAs Targeting Telomerase Subunits in Cancer Therapy. Cancers (Basel) 2020; 12:E2337. [PMID: 32825005 PMCID: PMC7565511 DOI: 10.3390/cancers12092337] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 08/15/2020] [Accepted: 08/17/2020] [Indexed: 12/15/2022] Open
Abstract
Telomerase provides cancer cells with replicative immortality, and its overexpression serves as a near-universal marker of cancer. Anti-cancer therapeutics targeting telomerase have garnered interest as possible alternatives to chemotherapy and radiotherapy. Oligonucleotide-based therapies that inhibit telomerase through direct or indirect modulation of its subunits, human telomerase reverse transcriptase (hTERT) and human telomerase RNA gene (hTERC), are a unique and diverse subclass of telomerase inhibitors which hold clinical promise. MicroRNAs that play a role in the upregulation or downregulation of hTERT and respective progression or attenuation of cancer development have been effectively targeted to reduce telomerase activity in various cancer types. Tumor suppressor miRNAs, such as miRNA-512-5p, miRNA-138, and miRNA-128, and oncogenic miRNAs, such as miRNA-19b, miRNA-346, and miRNA-21, have displayed preclinical promise as potential hTERT-based therapeutic targets. Antisense oligonucleotides like GRN163L and T-oligos have also been shown to uniquely target the telomerase subunits and have become popular in the design of novel cancer therapies. Finally, studies suggest that G-quadruplex stabilizers, such as Telomestatin, preserve telomeric oligonucleotide architecture, thus inhibiting hTERC binding to the telomere. This review aims to provide an adept understanding of the conceptual foundation and current state of therapeutics utilizing oligonucleotides to target the telomerase subunits, including the advantages and drawbacks of each of these approaches.
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Affiliation(s)
| | | | | | | | - Neelu Puri
- Department of Biomedical Sciences, University of Illinois College of Medicine at Rockford, Rockford, IL 61107, USA; (A.E.); (J.D.); (J.B.); (Z.S.)
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4
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Trybek T, Kowalik A, Góźdź S, Kowalska A. Telomeres and telomerase in oncogenesis. Oncol Lett 2020; 20:1015-1027. [PMID: 32724340 PMCID: PMC7377093 DOI: 10.3892/ol.2020.11659] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 03/25/2020] [Indexed: 12/24/2022] Open
Abstract
Telomeres are located at the ends of chromosomes and protect them from degradation. Suppressing the activity of telomerase, a telomere-synthesizing enzyme, and maintaining short telomeres is a protective mechanism against cancer in humans. In most human somatic cells, the expression of telomerase reverse transcriptase (TERT) is repressed and telomerase activity is inhibited. This leads to the progressive shortening of telomeres and inhibition of cell growth in a process called replicative senescence. Most types of primary cancer exhibit telomerase activation, which allows uncontrolled cell proliferation. Previous research indicates that TERT activation also affects cancer development through activities other than the canonical function of mediating telomere elongation. Recent studies have improved the understanding of the structure and function of telomeres and telomerase as well as key mechanisms underlying the activation of TERT and its role in oncogenesis. These advances led to a search for drugs that inhibit telomerase as a target for cancer therapy. The present review article summarizes the organization and function of telomeres, their role in carcinogenesis, and advances in telomerase-targeted therapy.
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Affiliation(s)
- Tomasz Trybek
- Endocrinology Clinic, Holycross Cancer Center, 25-734 Kielce, Poland
| | - Artur Kowalik
- Department of Molecular Diagnostics, Holycross Cancer Center, 25-734 Kielce, Poland
| | - Stanisław Góźdź
- The Faculty of Health Sciences, Jan Kochanowski University, 25-319 Kielce, Poland.,Oncology Clinic, Holycross Cancer Center, 25-734 Kielce, Poland
| | - Aldona Kowalska
- Endocrinology Clinic, Holycross Cancer Center, 25-734 Kielce, Poland.,The Faculty of Health Sciences, Jan Kochanowski University, 25-319 Kielce, Poland
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5
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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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6
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Chen X, Tang WJ, Shi JB, Liu MM, Liu XH. Therapeutic strategies for targeting telomerase in cancer. Med Res Rev 2019; 40:532-585. [PMID: 31361345 DOI: 10.1002/med.21626] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 07/12/2019] [Accepted: 07/16/2019] [Indexed: 12/13/2022]
Abstract
Telomere and telomerase play important roles in abnormal cell proliferation, metastasis, stem cell maintenance, and immortalization in various cancers. Therefore, designing of drugs targeting telomerase and telomere is of great significance. Over the past two decades, considerable knowledge regarding telomere and telomerase has been accumulated, which provides theoretical support for the design of therapeutic strategies such as telomere elongation. Therefore, the development of telomere-based therapies such as nucleoside analogs, non-nucleoside small molecules, antisense technology, ribozymes, and dominant negative human telomerase reverse transcriptase are being prioritized for eradicating a majority of tumors. While the benefits of telomere-based therapies are obvious, there is a need to address the limitations of various therapeutic strategies to improve the possibility of clinical applications. In this study, current knowledge of telomere and telomerase is discussed, and therapeutic strategies based on recent research are reviewed.
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Affiliation(s)
- Xing Chen
- School of Pharmacy, Anhui Province Key Laboratory of Major Autoimmune Diseases, Anhui Medical University, Hefei, People's Republic of China
| | - Wen-Jian Tang
- School of Pharmacy, Anhui Province Key Laboratory of Major Autoimmune Diseases, Anhui Medical University, Hefei, People's Republic of China
| | - Jing Bo Shi
- School of Pharmacy, Anhui Province Key Laboratory of Major Autoimmune Diseases, Anhui Medical University, Hefei, People's Republic of China
| | - Ming Ming Liu
- School of Pharmacy, Anhui Province Key Laboratory of Major Autoimmune Diseases, Anhui Medical University, Hefei, People's Republic of China
| | - Xin-Hua Liu
- School of Pharmacy, Anhui Province Key Laboratory of Major Autoimmune Diseases, Anhui Medical University, Hefei, People's Republic of China
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7
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Quantitative Biology of Human Shelterin and Telomerase: Searching for the Weakest Point. Int J Mol Sci 2019; 20:ijms20133186. [PMID: 31261825 PMCID: PMC6651453 DOI: 10.3390/ijms20133186] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 06/12/2019] [Accepted: 06/27/2019] [Indexed: 02/06/2023] Open
Abstract
The repetitive telomeric DNA at chromosome ends is protected from unwanted repair by telomere-associated proteins, which form the shelterin complex in mammals. Recent works have provided new insights into the mechanisms of how human shelterin assembles and recruits telomerase to telomeres. Inhibition of telomerase activity and telomerase recruitment to chromosome ends is a promising target for anticancer therapy. Here, we summarize results of quantitative assessments and newly emerged structural information along with the status of the most promising approaches to telomerase inhibition in cancer cells. We focus on the mechanism of shelterin assembly and the mechanisms of how shelterin affects telomerase recruitment to telomeres, addressing the conceptual dilemma of how shelterin allows telomerase action and regulates other essential processes. We evaluate how the identified critical interactions of telomerase and shelterin might be elucidated in future research of new anticancer strategies.
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8
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Zhou XQ, Ren J, Yang S. [Relationship between thrombospondin-1 and the occurrence and development of oral and maxillofacial malignancy]. HUA XI KOU QIANG YI XUE ZA ZHI = HUAXI KOUQIANG YIXUE ZAZHI = WEST CHINA JOURNAL OF STOMATOLOGY 2018; 36:686-690. [PMID: 30593119 DOI: 10.7518/hxkq.2018.06.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Thrombospondin-1 (TSP-1) is widely distributed in human tissues and is important in inhibiting angiogenesis.It also occupies an indispensable position in the formation, growth, differentiation, and metastasis of tumors in different tissues.TSP-1 plays an important role in the occurrence and development of various types of tumors. The inhibitory effect of TSP-1 on the angiogenesis and tumor development of oral and maxillofacial malignant tumors has been demonstrated in recent years. This paper reviews the findings and progress of TSP-1 research involving all kinds of tumors as well as oral and maxillofacial malignancies.
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Affiliation(s)
- Xue-Qin Zhou
- Graduate School, Zunyi Medical University, Zunyi 563000, China;Dept. of Oral and Maxillofacial Surgery, Suining Central Hospital, Suining 629000, China
| | - Jun Ren
- Graduate School, Zunyi Medical University, Zunyi 563000, China;Dept. of Oral and Maxillofacial Surgery, Suining Central Hospital, Suining 629000, China
| | - Sen Yang
- Graduate School, Zunyi Medical University, Zunyi 563000, China;Dept. of Oral and Maxillofacial Surgery, Suining Central Hospital, Suining 629000, China
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9
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Assani G, Xiong Y, Zhou F, Zhou Y. Effect of therapies-mediated modulation of telomere and/or telomerase on cancer cells radiosensitivity. Oncotarget 2018; 9:35008-35025. [PMID: 30405890 PMCID: PMC6201854 DOI: 10.18632/oncotarget.26150] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 07/31/2018] [Indexed: 12/11/2022] Open
Abstract
Cancer is one of the leading causes of death in the world. Many strategies of cancer treatment such as radiotherapy which plays a key role in cancer treatment are developed and used nowadays. However, the side effects post-cancer radiotherapy and cancer radioresistance are two major causes of the limitation of cancer radiotherapy effectiveness in the cancer patients. Moreover, reduction of the limitation of cancer radiotherapy effectiveness by reducing the side effects post-cancer radiotherapy and cancer radioresistance is the aim of several radiotherapy-oncologic teams. Otherwise, Telomere and telomerase are two cells components which play an important role in cancer initiation, cancer progression and cancer therapy resistance such as radiotherapy resistance. For resolving the problems of the limitation of cancer radiotherapy effectiveness especially the cancer radio-resistance problems, the radio-gene-therapy strategy which is the use of gene-therapy via modulation of gene expression combined with radiotherapy was developed and used as a new strategy to treat the patients with cancer. In this review, we summarized the information concerning the implication of telomere and telomerase modulation in cancer radiosensitivity.
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Affiliation(s)
- Ganiou Assani
- Department of Radiation and Medical Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China
- Hubei Cancer Clinical Study Center, Zhongnan Hospital of Wuhan University, Wuhan, China
- Hubei Key Laboratory of Tumor Biology Behaviors, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Yudi Xiong
- Department of Radiation and Medical Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China
- Hubei Cancer Clinical Study Center, Zhongnan Hospital of Wuhan University, Wuhan, China
- Hubei Key Laboratory of Tumor Biology Behaviors, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Fuxiang Zhou
- Department of Radiation and Medical Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China
- Hubei Cancer Clinical Study Center, Zhongnan Hospital of Wuhan University, Wuhan, China
- Hubei Key Laboratory of Tumor Biology Behaviors, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Yunfeng Zhou
- Department of Radiation and Medical Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China
- Hubei Cancer Clinical Study Center, Zhongnan Hospital of Wuhan University, Wuhan, China
- Hubei Key Laboratory of Tumor Biology Behaviors, Zhongnan Hospital of Wuhan University, Wuhan, China
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10
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Schrank Z, Khan N, Osude C, Singh S, Miller RJ, Merrick C, Mabel A, Kuckovic A, Puri N. Oligonucleotides Targeting Telomeres and Telomerase in Cancer. Molecules 2018; 23:molecules23092267. [PMID: 30189661 PMCID: PMC6225148 DOI: 10.3390/molecules23092267] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 08/27/2018] [Accepted: 09/04/2018] [Indexed: 02/07/2023] Open
Abstract
Telomeres and telomerase have become attractive targets for the development of anticancer therapeutics due to their involvement in cancer cell immortality. Currently, several therapeutics have been developed that directly target telomerase and telomeres, such as telomerase inhibitors and G-quadruplex stabilizing ligands. Telomere-specific oligonucleotides that reduce telomerase activity and disrupt telomere architecture are also in development as novel anticancer therapeutics. Specifically, GRN163L and T-oligos have demonstrated promising anticancer activity in multiple cancers types via induction of potent DNA damage responses. Currently, several miRNAs have been implicated in the regulation of telomerase activity and may prove to be valuable targets in the development of novel therapies by reducing expression of telomerase subunits. Targeting miRNAs that are known to increase expression of telomerase subunits may be another strategy to reduce carcinogenesis. This review aims to provide a comprehensive understanding of current oligonucleotide-based anticancer therapies that target telomeres and telomerase. These studies may help design novel therapeutic approaches to overcome the challenges of oligonucleotide therapy in a clinical setting.
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Affiliation(s)
- Zachary Schrank
- Department of Biomedical Sciences, University of Illinois College of Medicine at Rockford, Rockford, IL 61107, USA.
| | - Nabiha Khan
- Department of Biomedical Sciences, University of Illinois College of Medicine at Rockford, Rockford, IL 61107, USA.
| | - Chike Osude
- Department of Biomedical Sciences, University of Illinois College of Medicine at Rockford, Rockford, IL 61107, USA.
| | - Sanjana Singh
- Department of Biomedical Sciences, University of Illinois College of Medicine at Rockford, Rockford, IL 61107, USA.
| | - Rachel J Miller
- Department of Biomedical Sciences, University of Illinois College of Medicine at Rockford, Rockford, IL 61107, USA.
| | - Collin Merrick
- Department of Biomedical Sciences, University of Illinois College of Medicine at Rockford, Rockford, IL 61107, USA.
| | - Alexander Mabel
- Department of Biomedical Sciences, University of Illinois College of Medicine at Rockford, Rockford, IL 61107, USA.
| | - Adijan Kuckovic
- Department of Biomedical Sciences, University of Illinois College of Medicine at Rockford, Rockford, IL 61107, USA.
| | - Neelu Puri
- Department of Biomedical Sciences, University of Illinois College of Medicine at Rockford, Rockford, IL 61107, USA.
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11
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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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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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13
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Velarde MC, Menon R. Positive and negative effects of cellular senescence during female reproductive aging and pregnancy. J Endocrinol 2016; 230:R59-76. [PMID: 27325241 DOI: 10.1530/joe-16-0018] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2016] [Accepted: 06/17/2016] [Indexed: 12/21/2022]
Abstract
Cellular senescence is a phenomenon occurring when cells are no longer able to divide even after treatment with growth stimuli. Because senescent cells are typically associated with aging and age-related diseases, cellular senescence is hypothesized to contribute to the age-related decline in reproductive function. However, some data suggest that senescent cells may also be important for normal physiological functions during pregnancy. Herein, we review the positive and negative effects of cellular senescence on female reproductive aging and pregnancy. We discuss how senescent cells accelerate female reproductive aging by promoting the decline in the number of ovarian follicles and increasing complications during pregnancy. We also describe how cellular senescence plays an important role in placental and fetal development as a beneficial process, ensuring proper homeostasis during pregnancy.
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Affiliation(s)
- Michael C Velarde
- Institute of BiologyUniversity of the Philippines Diliman, Quezon City, Philippines Buck Institute for Research on AgingNovato, California, USA
| | - Ramkumar Menon
- Department of Obstetrics and GynecologyUniversity of Texas Medical Branch at Galveston, Galveston, Texas, USA Department of Clinical Medicine and Obstetrics and GynecologyAarhus University, Aarhus, Denmark
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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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Engelmann D, Meier C, Alla V, Pützer BM. A balancing act: orchestrating amino-truncated and full-length p73 variants as decisive factors in cancer progression. Oncogene 2014; 34:4287-99. [PMID: 25381823 DOI: 10.1038/onc.2014.365] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Revised: 09/24/2014] [Accepted: 09/29/2014] [Indexed: 12/23/2022]
Abstract
p73 is the older sibling of p53 and mimics most of its tumor-suppressor functions. Through alternative promoter usage and splicing, the TP73 gene generates more than two dozen isoforms of which N-terminal truncated DNp73 variants have a decisive role in cancer pathogenesis as they outweigh the positive effects of full-length TAp73 and p53 in acting as a barrier to tumor development. Beyond the prevailing view that DNp73 predominantly counteract cell cycle arrest and apoptosis, latest progress indicates that these isoforms acquire novel functions in epithelial-to-mesenchymal transition, metastasis and therapy resistance. New insight into the mechanisms underlying this behavior reinforced the expectation that DNp73 variants contribute to aggressive cellular traits through both loss of wild-type tumor-suppressor activity and gain-of-function, suggesting an equally important role in cancer progression as mutant p53. In this review, we describe the novel properties of DNp73 in the invasion metastasis cascade and outline the comprehensive p73 regulatome with an emphasis on molecular processes putting TAp73 out of action in advanced tumors. These intriguing insights provoke a new understanding of the acquisition of aggressive traits by cancer cells and may help to set novel therapies for a broad range of metastatic tumors.
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Affiliation(s)
- D Engelmann
- Institute of Experimental Gene Therapy and Cancer Research, Rostock University Medical Center, Rostock, Germany
| | - C Meier
- Institute of Experimental Gene Therapy and Cancer Research, Rostock University Medical Center, Rostock, Germany
| | - V Alla
- Institute of Experimental Gene Therapy and Cancer Research, Rostock University Medical Center, Rostock, Germany
| | - B M Pützer
- Institute of Experimental Gene Therapy and Cancer Research, Rostock University Medical Center, Rostock, Germany
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Poenaru Sava MG, Raica ML, Cimpean AMG. VEGF mRNA assessment in human pterygium: a new 'scope' for a future hope. Ophthalmic Res 2014; 52:130-5. [PMID: 25300614 DOI: 10.1159/000363142] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Accepted: 04/18/2014] [Indexed: 11/19/2022]
Abstract
PURPOSE The lack of powerful evidence to support the efficacy of anti-vascular endothelial growth factor (VEGF) therapy in human pterygium can be attributed to incomplete VEGF expression assessment by restrictive use of immunohistochemistry only and failure to use the molecular methods able to confirm immunohistochemical findings. By adding at least one more sensitive method to assess human pterygium VEGF expression, a more accurate selection of patients for bevacizumab therapy could be done and this would improve the efficacy of anti-VEGF therapy in human pterygium. METHODS We assessed VEGF mRNA amplification on paraffin-embedded specimens by applying the RNAscope method for the first time in human pterygium, an in situ hybridization-based technique able to detect VEGF mRNA as a single gene copy on paraffin-embedded samples. RESULTS Heterogeneous VEGF mRNA distribution and amplification inside the epithelial compartment of human pterygium were observed. Despite previous reports concerning the immunohistochemical expression of VEGF in the human pterygium fibrovascular compartment, no stromal components were characterized by VEGF mRNA amplification assessed by in situ hybridization in our study. A higher amplification score was observed in epithelium from recurrent pterygium, especially located in the basal and suprabasal epithelial cells. CONCLUSIONS Based on our findings we consider that in situ hybridization assessment of VEGF for human pterygium specimens can be a useful tool for reconsidering the selection of pterygium patients to be enrolled in anti-VEGF therapy.
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Affiliation(s)
- Mihai G Poenaru Sava
- Department of Ophthalmology, Angiogenesis Research Center, Victor Babeş University of Medicine and Pharmacy, Timisoara, Romania
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Etnyre D, Stone AL, Fong JT, Jacobs RJ, Uppada SB, Botting GM, Rajanna S, Moravec DN, Shambannagari MR, Crees Z, Girard J, Bertram C, Puri N. Targeting c-Met in melanoma: mechanism of resistance and efficacy of novel combinatorial inhibitor therapy. Cancer Biol Ther 2014; 15:1129-41. [PMID: 24914950 PMCID: PMC4128856 DOI: 10.4161/cbt.29451] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Numerous tyrosine kinase inhibitors (TKIs) targeting c-Met are currently in clinical trials for several cancers. Their efficacy is limited due to the development of resistance. The present study aims to elucidate this mechanism of c-Met TKI resistance by investigating key mTOR and Wnt signaling proteins in melanoma cell lines resistant to SU11274, a c-Met TKI. Xenografts from RU melanoma cells treated with c-Met TKIs SU11274 and JNJ38877605 showed a 7- and 6-fold reduction in tumor size, respectively. Resistant cells displayed upregulation of phosphorylated c-Met, mTOR, p70S6Kinase, 4E-BP1, ERK, LRP6, and active β-catenin. In addition, GATA-6, a Wnt signaling regulator, was upregulated, and Axin, a negative regulator of the Wnt pathway, was downregulated in resistant cells. Modulation of these mTOR and Wnt pathway proteins was also prevented by combination treatment with SU11274, everolimus, an mTOR inhibitor, and XAV939, a Wnt inhibitor. Treatment with everolimus, resulted in 56% growth inhibition, and a triple combination of SU11274, everolimus and XAV939, resulted in 95% growth inhibition in RU cells. The V600E BRAF mutation was found to be positive only in MU cells. Combination treatment with a c-Met TKI and a BRAF inhibitor displayed a synergistic effect in reducing MU cell viability. These studies indicate activation of mTOR and Wnt signaling pathways in c-Met TKI resistant melanoma cells and suggest that concurrent targeting of c-Met, mTOR, and Wnt pathways and BRAF may improve efficacy over traditional TKI monotherapy in melanoma patients.
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Affiliation(s)
- Deven Etnyre
- Department of Biomedical Sciences; University of Illinois College of Medicine; Rockford, IL USA
| | - Amanda L Stone
- Department of Biomedical Sciences; University of Illinois College of Medicine; Rockford, IL USA
| | - Jason T Fong
- Department of Biomedical Sciences; University of Illinois College of Medicine; Rockford, IL USA
| | - Ryan J Jacobs
- Department of Biomedical Sciences; University of Illinois College of Medicine; Rockford, IL USA
| | - Srijayaprakash B Uppada
- Department of Biomedical Sciences; University of Illinois College of Medicine; Rockford, IL USA
| | - Gregory M Botting
- Department of Biomedical Sciences; University of Illinois College of Medicine; Rockford, IL USA
| | - Supriya Rajanna
- Department of Biomedical Sciences; University of Illinois College of Medicine; Rockford, IL USA
| | - David N Moravec
- Department of Biomedical Sciences; University of Illinois College of Medicine; Rockford, IL USA
| | - Manohar R Shambannagari
- Department of Biomedical Sciences; University of Illinois College of Medicine; Rockford, IL USA
| | - Zachary Crees
- Department of Biomedical Sciences; University of Illinois College of Medicine; Rockford, IL USA
| | - Jennifer Girard
- Department of Biomedical Sciences; University of Illinois College of Medicine; Rockford, IL USA
| | - Ceyda Bertram
- Department of Biomedical Sciences; University of Illinois College of Medicine; Rockford, IL USA
| | - Neelu Puri
- Department of Biomedical Sciences; University of Illinois College of Medicine; Rockford, IL USA
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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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Uppada SB, Erickson T, Wojdyla L, Moravec DN, Song Z, Cheng J, Puri N. Novel delivery system for T-oligo using a nanocomplex formed with an alpha helical peptide for melanoma therapy. Int J Nanomedicine 2013; 9:43-53. [PMID: 24391441 PMCID: PMC3879016 DOI: 10.2147/ijn.s55133] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Oligonucleotides homologous to 3′-telomere overhang (T-oligos) trigger inherent telomere-based DNA damage responses mediated by p53 and/or ATM and induce senescence or apoptosis in various cancerous cells. However, T-oligo has limited stability in vivo due to serum and intracellular nucleases. To develop T-oligo as an innovative, effective therapeutic drug and to understand its mechanism of action, we investigated the antitumor effects of T-oligo or T-oligo complexed with a novel cationic alpha helical peptide, PVBLG-8 (PVBLG), in a p53 null melanoma cell line both in vitro and in vivo. The uptake of T-oligo by MM-AN cells was confirmed by immunofluorescence, and fluorescence-activated cell sorting analysis indicated that the T-oligo-PVBLG nanocomplex increased uptake by 15-fold. In vitro results showed a 3-fold increase in MM-AN cell growth inhibition by the T-oligo-PVBLG nanocomplex compared with T-oligo alone. Treatment of preformed tumors in immunodeficient mice with the T-oligo-PVBLG nanocomplex resulted in a 3-fold reduction in tumor volume compared with T-oligo alone. This reduction in tumor volume was associated with decreased vascular endothelial growth factor expression and induction of thrombospondin-1 expression and apoptosis. Moreover, T-oligo treatment downregulated procaspase-3 and procaspase-7 and increased catalytic activity of caspase-3 by 4-fold in MM-AN cells. Furthermore, T-oligo induced a 10-fold increase of senescence and upregulated the melanoma tumor-associated antigens MART-1, tyrosinase, and thrombospondin-1 in MM-AN cells, which are currently being targeted for melanoma immunotherapy. Interestingly, siRNA-mediated knockdown of p73 (4–10-fold) abolished this upregulation of tumor-associated antigens. In summary, we suggest a key role of p73 in mediating the anticancer effects of T-oligo and introduce a novel nanoparticle, the T-oligo-PVBLG nanocomplex, as an effective anticancer therapeutic.
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Affiliation(s)
- Srijayaprakash B Uppada
- Department of Biomedical Sciences, University of Illinois College of Medicine at Rockford, Rockford, IL, USA
| | - Terrianne Erickson
- Department of Biomedical Sciences, University of Illinois College of Medicine at Rockford, Rockford, IL, USA
| | - Luke Wojdyla
- Department of Biomedical Sciences, University of Illinois College of Medicine at Rockford, Rockford, IL, USA
| | - David N Moravec
- Department of Biomedical Sciences, University of Illinois College of Medicine at Rockford, Rockford, IL, USA
| | - Ziyuan Song
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Jianjun Cheng
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Neelu Puri
- Department of Biomedical Sciences, University of Illinois College of Medicine at Rockford, Rockford, IL, USA
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