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Li F, Zhang G, Liang J, Ma Y, Huang J, Wang R, Du H, Wang G, Wang Q. Protection of Intestinal Barrier in Uremic Mice by Electroacupuncture via Regulating the Cannabinoid 1 Receptor of the Intestinal Glial Cells. J Biomed Nanotechnol 2021; 17:2210-2218. [PMID: 34906281 DOI: 10.1166/jbn.2021.3186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Intestinal barrier injuries are common in uremia, which aggravates uremia. The goal of this study is to learn moreabout how electroacupuncture regulates gastrointestinal function, as well as to identify the importance of microglia in electroacupuncture regulation and the cannabinoid receptor signaling pathway in controlling the activity of intestinal glial cells. The mice were arbitrarily assigned to four groups: control, CKD, electroacupuncture stimulation, or AM251 (CB1 receptor antagonist). The mice model of uremia was established by adenine gavage. Western blotting revealed the development of tight junction proteins ZO-1, cannabinoid 1 receptor, glial specific GFAP, occludin, S100 β, claudin-1, and JNK. GFAP and CB1R protein expression and co-localization of the intestinal glial cells were observed by double-labeled fluorescence. The expression of cannabinoid 1 receptor CB1R in the intestinal glial cells was increased after electroacupuncture. The expression of tight junction protein, GFAP, S100 β, and CB1R protein was up-regulated after electroacupuncture, and the dysfunction of the intestinal barrier in uremia was corrected. Nevertheless, AM251, a CB1R antagonist, reversed the effect of electroacupuncture. Electroacupuncture can protect the intestinal barrier through the intestinal glial cell CB1R, and the effect is achieved by inhibiting the JNK pathway.
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Affiliation(s)
- Feng Li
- Department of Anesthesiology, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, China
| | - Guangjian Zhang
- Department of Thoracic Surgery, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, China
| | - Jing Liang
- Department of Radiotherapy, Shaanxi Provincial Tumor Hospital, Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, China
| | - Yu Ma
- Department of Anesthesiology, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, China
| | - Jian Huang
- Department of Anesthesiology, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, China
| | - Rui Wang
- Department of Anesthesiology, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, China
| | - Hailiang Du
- Department of Anesthesiology, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, China
| | - Ge Wang
- Department of Anesthesiology, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, China
| | - Qiang Wang
- Department of Anesthesiology, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, China
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Choi SH, Cho KJ, Yun SH, Jin B, Lee HY, Ro SW, Kim DY, Ahn SH, Han KH, Park JY. HKR3 regulates cell cycle through the inhibition of hTERT in hepatocellular carcinoma cell lines. J Cancer 2020; 11:2442-2452. [PMID: 32201515 PMCID: PMC7066026 DOI: 10.7150/jca.39380] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 01/20/2020] [Indexed: 12/12/2022] Open
Abstract
Hepatocellular carcinoma is a malignant disease with improved hepatic regeneration and survival, and is activated by human telomere transferase (hTERT). hTERT is expressed during early fetal development and switched off in most adult tissues, but it becomes reactivated in HCC. The exact mechanism regulating these expression changes remains unknown during HCC progress. We evaluated the relationship between hTERT expression and human kruppel-related 3 (HKR3) and cell cycle-related factors in HCC cell lines. Following transfection for hTERT knockdown and HKR3 overexpression, proteomic and transcriptomic analyses related to hTERT were performed using liquid chromatography/mass spectrometry (LC/MS) and RNA sequencing (RNAseq) in HCC cell lines. The expression levels of hTERT, HKR3, and cell cycle-related factors were measured using western blotting, and tumor growth were evaluated via cell proliferation and cell cycle assays. Transcriptomic and proteomic analyses showed that HKR3, hTERT and cyclin-dependent kinase inhibitor 2A (CDKN2A) were correlated. Up-regulation of HKR3 expression decreased hTERT and cyclin activation and suppressed the G1/S phase of the cell cycle through CDKN2A activation. Our results suggest that HKR3 induced regulation of cell cycle through hTERT inhibition and CDKN2A activation. Our results will facilitate further exploration of the pathways regulating human telomerase activity in HCC cell lines.
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Affiliation(s)
- Sung Hoon Choi
- Yonsei Liver Center, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Kyung Joo Cho
- Yonsei Liver Center, Yonsei University College of Medicine, Seoul, Republic of Korea.,BK21 plus project for medical science, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Sung Ho Yun
- Division of Bioconvergence Analysis, Drug & Disease Target Team, Korea Basic Science Institute (KBSI), Cheongju, Republic of Korea
| | - Bora Jin
- Yonsei Liver Center, Yonsei University College of Medicine, Seoul, Republic of Korea.,BK21 plus project for medical science, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Ha Young Lee
- Division of Bioconvergence Analysis, Drug & Disease Target Team, Korea Basic Science Institute (KBSI), Cheongju, Republic of Korea.,Bio-Analysis Science, University of Science & Technology (UST), 217 Gajeong-ro, Yuseong-gu, Daejeon, Republic of Korea
| | - Simon W Ro
- Yonsei Liver Center, Yonsei University College of Medicine, Seoul, Republic of Korea.,Department of Internal Medicine, Institute of Gastroenterology, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Do Young Kim
- Yonsei Liver Center, Yonsei University College of Medicine, Seoul, Republic of Korea.,Department of Internal Medicine, Institute of Gastroenterology, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Sang Hoon Ahn
- Yonsei Liver Center, Yonsei University College of Medicine, Seoul, Republic of Korea.,BK21 plus project for medical science, Yonsei University College of Medicine, Seoul, Republic of Korea.,Department of Internal Medicine, Institute of Gastroenterology, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Kwang-Hyub Han
- Yonsei Liver Center, Yonsei University College of Medicine, Seoul, Republic of Korea.,Division of Bioconvergence Analysis, Drug & Disease Target Team, Korea Basic Science Institute (KBSI), Cheongju, Republic of Korea.,Department of Internal Medicine, Institute of Gastroenterology, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Jun Yong Park
- Yonsei Liver Center, Yonsei University College of Medicine, Seoul, Republic of Korea.,BK21 plus project for medical science, Yonsei University College of Medicine, Seoul, Republic of Korea.,Department of Internal Medicine, Institute of Gastroenterology, Yonsei University College of Medicine, Seoul, Republic of Korea
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3
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Barczak W, Sobecka A, Golusinski P, Masternak MM, Rubis B, Suchorska WM, Golusinski W. hTERT gene knockdown enhances response to radio- and chemotherapy in head and neck cancer cell lines through a DNA damage pathway modification. Sci Rep 2018; 8:5949. [PMID: 29654294 PMCID: PMC5899166 DOI: 10.1038/s41598-018-24503-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 04/04/2018] [Indexed: 12/11/2022] Open
Abstract
The aim of the study was to analyze the effect of hTERT gene knockdown in HNSCC cells by using novel in vitro models of head and neck cancer (HNSCC), as well as improving its personalized therapy. To obtain the most efficient knockdown siRNA, shRNA-bearing lentiviral vectors were used. The efficiency of hTERT silencing was verified with qPCR, Western blot, and immunofluorescence staining. Subsequently, the type of cell death and DNA repair mechanism induction after hTERT knockdown was assessed with the same methods, followed by flow cytometry. The effect of a combined treatment with hTERT gene knockdown on Double-Strand Breaks levels was also evaluated by flow cytometry. Results showed that the designed siRNAs and shRNAs were effective in hTERT knockdown in HNSCC cells. Depending on a cell line, hTERT knockdown led to a cell cycle arrest either in phase G1 or phase S/G2. Induction of apoptosis after hTERT downregulation with siRNA was observed. Additionally, hTERT targeting with lentiviruses, followed by cytostatics administration, led to induction of apoptosis. Interestingly, an increase in Double-Strand Breaks accompanied by activation of the main DNA repair mechanism, NER, was also observed. Altogether, we conclude that hTERT knockdown significantly contributes to the efficacy of HNSCC treatment.
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Affiliation(s)
- Wojciech Barczak
- Department of Head and Neck Surgery, Poznan University of Medical Sciences, The Greater Poland Cancer Centre, Garbary 15 Str., 61-866, Poznan, Poland. .,Radiobiology Lab, The Greater Poland Cancer Centre, Garbary 15 Str., 61-866, Poznan, Poland.
| | - Agnieszka Sobecka
- Department of Head and Neck Surgery, Poznan University of Medical Sciences, The Greater Poland Cancer Centre, Garbary 15 Str., 61-866, Poznan, Poland.,Radiobiology Lab, The Greater Poland Cancer Centre, Garbary 15 Str., 61-866, Poznan, Poland
| | - Pawel Golusinski
- Department of Head and Neck Surgery, Poznan University of Medical Sciences, The Greater Poland Cancer Centre, Garbary 15 Str., 61-866, Poznan, Poland.,Head and Neck Cancer Biology Lab, Department of Biology and Environmental Studies, Poznan University of Medical Sciences, Poznan, Poland
| | - Michal M Masternak
- Department of Head and Neck Surgery, Poznan University of Medical Sciences, The Greater Poland Cancer Centre, Garbary 15 Str., 61-866, Poznan, Poland.,University of Central Florida, Burnett School of Biomedical Sciences, College of Medicine, FL, 32827, Orlando, USA
| | - Blazej Rubis
- Department of Clinical Chemistry and Molecular Diagnostics, Poznan University of Medical Sciences, Przybyszewskiego 49 Str., 60-355, Poznan, Poland
| | - Wiktoria M Suchorska
- Radiobiology Lab, The Greater Poland Cancer Centre, Garbary 15 Str., 61-866, Poznan, Poland.,Department of Electroradiology, Poznan University of Medical Sciences, Garbary 15 Str., 61-866, Poznan, Poland
| | - Wojciech Golusinski
- Department of Head and Neck Surgery, Poznan University of Medical Sciences, The Greater Poland Cancer Centre, Garbary 15 Str., 61-866, Poznan, Poland
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Ma Q, Yu Y, Dai L, Qu X, Cong S, Liang H. Effect of TERT on the growth of fibrosarcoma via caspase-3, survivin and PKB. Oncol Lett 2017; 14:1939-1942. [PMID: 28789428 DOI: 10.3892/ol.2017.6373] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 01/06/2017] [Indexed: 01/17/2023] Open
Abstract
The present study explored the effect of telomerase reverse transcriptase (TERT) on the growth and apoptosis of fibrosarcoma, and investigated the potential molecular signalling pathways underlying its effect. A plasmid was constructed in order to overexpress TERT and siRNA was used to knockdown TERT. The effect of TERT on fibrosarcoma cells in vitro was studied by performing reverse transcription-quantitative PCR and western blotting to determine the expression of p53, survivin, caspase-3, caspase-7 and PKB. Knockdown of TERT suppressed cell growth, decreased fibrosarcoma volume, decreased survivin and PKB expression, and increased caspase-3 expression. The results of the present study suggest that TERT regulates the growth of fibrosarcoma in vitro and in vivo, and that this is associated with the expression of caspase-3 and survivin, in addition to the PKB signalling pathway.
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Affiliation(s)
- Qiuye Ma
- Department of Orthopedics, Chinese Medicine Hospital of Jiulongpo, Chongqing 400080, P.R. China
| | - Yidong Yu
- Department of Orthopedics, Chinese Medicine Hospital of Jiulongpo, Chongqing 400080, P.R. China
| | - Linlin Dai
- Department of Orthopedics, The Fourth Affiliated Hospital of Harbin Medical University, Harbin, Helongjiang 150001, P.R. China
| | - Xuehua Qu
- Department of Orthopedics, The Fourth Affiliated Hospital of Harbin Medical University, Harbin, Helongjiang 150001, P.R. China
| | - Shan Cong
- Department of Orthopedics, The Fourth Affiliated Hospital of Harbin Medical University, Harbin, Helongjiang 150001, P.R. China
| | - Hongsuo Liang
- Department of Orthopedics, Nanning Second People's Hospital, Nanning, Guangxi 530031, P.R. China
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Abstract
Telomerase activity is responsible for the maintenance of chromosome end structures (telomeres) and cancer cell immortality in most human malignancies, making telomerase an attractive therapeutic target. The rationale for targeting components of the telomerase holoenzyme has been strengthened by accumulating evidence indicating that these molecules have extra-telomeric functions in tumour cell survival and proliferation. This Review discusses current knowledge of the biogenesis, structure and multiple functions of telomerase-associated molecules intertwined with recent advances in drug discovery approaches. We also describe the fertile ground available for the pursuit of next-generation small-molecule inhibitors of telomerase.
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Affiliation(s)
- Greg M Arndt
- Australian Cancer Research Foundation (ACRF) Drug Discovery Centre for Childhood Cancer, Children's Cancer Institute Australia, Lowy Cancer Research Centre, University of New South Wales, Randwick, New South Wales 2031, Australia
| | - Karen L MacKenzie
- Personalised Medicine Program, Children's Cancer Institute Australia, Lowy Cancer Research Centre, University of New South Wales, Randwick, New South Wales 2031, Australia
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Li H, Hao Y, Wang N, Wang L, Jia S, Wang Y, Yang L, Zhang Y, Zhang Z. DOTAP functionalizing single-walled carbon nanotubes as non-viral vectors for efficient intracellular siRNA delivery. Drug Deliv 2015; 23:840-8. [PMID: 24892622 DOI: 10.3109/10717544.2014.919542] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
CONTEXT Functionalized single-walled carbon nanotubes (SWNT) with 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) were used as novel and more convenient carriers of small interfering RNA (siRNA). OBJECTIVE To utilize the unique capability of SWNT to be easily modified by functional groups and readily internalized by mammalian cells to bind, condense, stabilize siRNA and enhance its transfection efficiency. METHODS After SWNT were non-covalently functionalized by cationic DOTAP (SWNT-DOTAP), siRNA interacted with SWNT-DOTAP via static electricity (SWNT-DOTAP/siRNA). Subsequently, the size, zeta potential and morphology of SWNT-DOTAP/siRNA were analyzed. The optimal compression ratio and stability of siRNA were assessed by agarose gel electrophoresis. Furthermore, in prostate carcinoma PC-3 cells, RT-PCR, flow cytometry and sulforhodamine B assays were used to evaluate the silencing activity, transfection efficiency and cell proliferation, respectively. RESULTS AND DISCUSSION The characteristics of SWNT-DOTAP, i.e. an average size of 194.49 nm, a zeta potential of 45.16 mV and lower cytotoxicity than Lipofectamine 2000, indicated that this vector was suitable for siRNA delivery. Moreover, after interaction with SWNT-DOTAP, siRNA of human telomerase reverse transcriptase was bound, condensed and stabilized. In PC-3 cells, SWNT-DOTAP/siRNA exhibited 82.6% silencing activity and 92% transfection efficiency. Furthermore, the complexes inhibited cell proliferation by 42.1%. CONCLUSION SWNT-DOTAP may be a promising siRNA delivery vector for gene-based therapeutic applications in cancer.
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Affiliation(s)
- Haixia Li
- a School of Pharmaceutical Sciences, Zhengzhou University , Zhengzhou 450002 , China
| | - Yongwei Hao
- a School of Pharmaceutical Sciences, Zhengzhou University , Zhengzhou 450002 , China
| | - Ning Wang
- a School of Pharmaceutical Sciences, Zhengzhou University , Zhengzhou 450002 , China .,b Department of pharmacy , the First Affiliated Hospital of Xinxiang Medical University , Xinxiang 453100 , China
| | - Lei Wang
- a School of Pharmaceutical Sciences, Zhengzhou University , Zhengzhou 450002 , China
| | - Shasha Jia
- a School of Pharmaceutical Sciences, Zhengzhou University , Zhengzhou 450002 , China
| | - Yali Wang
- a School of Pharmaceutical Sciences, Zhengzhou University , Zhengzhou 450002 , China
| | - Lijia Yang
- a School of Pharmaceutical Sciences, Zhengzhou University , Zhengzhou 450002 , China
| | - Yun Zhang
- a School of Pharmaceutical Sciences, Zhengzhou University , Zhengzhou 450002 , China
| | - Zhenzhong Zhang
- a School of Pharmaceutical Sciences, Zhengzhou University , Zhengzhou 450002 , China
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7
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Synthesis and biological evaluation of new curcumin analogues as antioxidant and antitumor agents: Molecular modeling study. Eur J Med Chem 2015. [DOI: 10.1016/j.ejmech.2015.07.014] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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8
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Silencing of the hTERT gene by shRNA inhibits colon cancer SW480 cell growth in vitro and in vivo. PLoS One 2014; 9:e107019. [PMID: 25207650 PMCID: PMC4160217 DOI: 10.1371/journal.pone.0107019] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Accepted: 04/14/2014] [Indexed: 01/17/2023] Open
Abstract
Human telomerase reverse transcriptase (hTERT) is the key enzyme responsible for synthesizing and maintaining the telomeres on the ends of chromosomes, and it is essential for cell proliferation. This has made hTERT a focus of oncology research and an attractive target for anticancer drug development. In this study, we designed a small interfering RNA (siRNA) targeting the catalytic subunit of hTERT and tested its effects on the growth of telomerase-positive human colon carcinoma SW480 cells in vitro, as well as on the tumorigenicity of these cells in nude mice. Transient and stable transfection of hTERT siRNA into colon cancer SW480 cells suppressed hTERT expression, reduced telomerase activity and inhibited cell growth and proliferation. Knocking down hTERT expression in SW480 tumors xenografted into nude mice significantly slowed tumor growth and promoted tumor cell apoptosis. Our results suggest that hTERT is involved in carcinogenesis of human colon carcinoma, and they highlight the therapeutic potential of a hTERT knock-down approach.
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Li D, Tang X, Pulli B, Lin C, Zhao P, Cheng J, Lv Z, Yuan X, Luo Q, Cai H, Ye M. Theranostic nanoparticles based on bioreducible polyethylenimine-coated iron oxide for reduction-responsive gene delivery and magnetic resonance imaging. Int J Nanomedicine 2014; 9:3347-61. [PMID: 25045265 PMCID: PMC4099417 DOI: 10.2147/ijn.s61463] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Theranostic nanoparticles based on superparamagnetic iron oxide (SPIO) have a great promise for tumor diagnosis and gene therapy. However, the availability of theranostic nanoparticles with efficient gene transfection and minimal toxicity remains a big challenge. In this study, we construct an intelligent SPIO-based nanoparticle comprising a SPIO inner core and a disulfide-containing polyethylenimine (SSPEI) outer layer, which is referred to as a SSPEI-SPIO nanoparticle, for redox-triggered gene release in response to an intracellular reducing environment. We reveal that SSPEI-SPIO nanoparticles are capable of binding genes to form nano-complexes and mediating a facilitated gene release in the presence of dithiothreitol (5–20 mM), thereby leading to high transfection efficiency against different cancer cells. The SSPEI-SPIO nanoparticles are also able to deliver small interfering RNA (siRNA) for the silencing of human telomerase reverse transcriptase genes in HepG2 cells, causing their apoptosis and growth inhibition. Further, the nanoparticles are applicable as T2-negative contrast agents for magnetic resonance (MR) imaging of a tumor xenografted in a nude mouse. Importantly, SSPEI-SPIO nanoparticles have relatively low cytotoxicity in vitro at a high concentration of 100 μg/mL. The results of this study demonstrate the utility of a disulfide-containing cationic polymer-decorated SPIO nanoparticle as highly potent and low-toxic theranostic nano-system for specific nucleic acid delivery inside cancer cells.
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Affiliation(s)
- Dan Li
- Department of Nuclear Medicine, Shanghai 10th People's Hospital, Tongji University School of Medicine, Tongji University, People's Republic of China
| | - Xin Tang
- Shanghai East Hospital, The Institute for Biomedical Engineering and Nanoscience, Tongji University School of Medicine, Tongji University, People's Republic of China
| | - Benjamin Pulli
- Department of Nuclear Medicine, Shanghai 10th People's Hospital, Tongji University School of Medicine, Tongji University, People's Republic of China
| | - Chao Lin
- Shanghai East Hospital, The Institute for Biomedical Engineering and Nanoscience, Tongji University School of Medicine, Tongji University, People's Republic of China
| | - Peng Zhao
- Shanghai East Hospital, The Institute for Biomedical Engineering and Nanoscience, Tongji University School of Medicine, Tongji University, People's Republic of China
| | - Jian Cheng
- Shanghai East Hospital, The Institute for Biomedical Engineering and Nanoscience, Tongji University School of Medicine, Tongji University, People's Republic of China
| | - Zhongwei Lv
- Department of Nuclear Medicine, Shanghai 10th People's Hospital, Tongji University School of Medicine, Tongji University, People's Republic of China
| | - Xueyu Yuan
- Department of Nuclear Medicine, Shanghai 10th People's Hospital, Tongji University School of Medicine, Tongji University, People's Republic of China
| | - Qiong Luo
- Department of Nuclear Medicine, Shanghai 10th People's Hospital, Tongji University School of Medicine, Tongji University, People's Republic of China
| | - Haidong Cai
- Department of Nuclear Medicine, Shanghai 10th People's Hospital, Tongji University School of Medicine, Tongji University, People's Republic of China
| | - Meng Ye
- Department of Nuclear Medicine, Shanghai 10th People's Hospital, Tongji University School of Medicine, Tongji University, People's Republic of China
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Shi YA, Zhao Q, Zhang LH, Du W, Wang XY, He X, Wu S, Li YL. Knockdown of hTERT by siRNA inhibits cervical cancer cell growth in vitro and in vivo. Int J Oncol 2014; 45:1216-24. [PMID: 24920549 DOI: 10.3892/ijo.2014.2493] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Accepted: 05/15/2014] [Indexed: 11/05/2022] Open
Abstract
Human telomerase reverse transcriptase (hTERT) is the catalytic component of telomerase that facilitates tumor cell invasion and proliferation. It has been reported that telomerase and hTERT are significantly upregulated in majority of cancers including cervical cancer, thus, downregulation of hTERT is a promising target in malignant tumor treatment. We established a short interfering RNA (siRNA) targeting hTERT, and transfected it into HeLa cells (a cervical cancer cell line) to investi-gate the effect of cell proliferation, apoptosis, migration and invasion in cervical cancer cells. The results showed that siRNA targeting hTERT could effectively knock down hTERT expression, remarkably suppress telomerase activity, cell proliferation, migration and invasion, and induced cell apoptosis of cervical cancers cells in vitro. In addition, we evaluated whether siRNA targeting hTERT affects tumor growth in nude mice, and found that it dramatically inhibited tumorigenesis and growth of mice injected with siRNA targeting hTERT. Furthermore, we also found that knockdown of hTERT was able to significantly suppress constitutive phosphorylation of Akt, PI3K, which might imply that reduction of hTERT inhibited tumor growth via the PI3K/Akt signaling pathway to some extent. These results suggest that the suppression of hTERT expression by siRNA inhibits cervical cancer cell growth in vitro and in vivo, and may provide a novel target for anticancer gene therapy.
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Affiliation(s)
- Ying-Ai Shi
- Key Laboratory of Pathobiology, Ministry of Education, School of Basic Medical Sciences, Jilin University, Changchun 130021, P.R. China
| | - Qiang Zhao
- Department of Pediatric Surgery, The First Hospital, Jilin University, Changchun 130021, P.R. China
| | - Li-Hong Zhang
- Key Laboratory of Pathobiology, Ministry of Education, School of Basic Medical Sciences, Jilin University, Changchun 130021, P.R. China
| | - Wei Du
- Key Laboratory of Pathobiology, Ministry of Education, School of Basic Medical Sciences, Jilin University, Changchun 130021, P.R. China
| | - Xue-Yao Wang
- Norman Bethune College of Medical Sciences, Jilin University, Changchun 130021, P.R. China
| | - Xu He
- Key Laboratory of Pathobiology, Ministry of Education, School of Basic Medical Sciences, Jilin University, Changchun 130021, P.R. China
| | - Shan Wu
- Key Laboratory of Pathobiology, Ministry of Education, School of Basic Medical Sciences, Jilin University, Changchun 130021, P.R. China
| | - Yu-Lin Li
- Key Laboratory of Pathobiology, Ministry of Education, School of Basic Medical Sciences, Jilin University, Changchun 130021, P.R. China
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Sekaran V, Soares J, Jarstfer MB. Telomere Maintenance as a Target for Drug Discovery. J Med Chem 2013; 57:521-38. [DOI: 10.1021/jm400528t] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Vijay Sekaran
- Division of Chemical Biology
and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Joana Soares
- Division of Chemical Biology
and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Michael B. Jarstfer
- Division of Chemical Biology
and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
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12
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Telomerase downregulation induces proapoptotic genes expression and initializes breast cancer cells apoptosis followed by DNA fragmentation in a cell type dependent manner. Mol Biol Rep 2013; 40:4995-5004. [PMID: 23677713 PMCID: PMC3723976 DOI: 10.1007/s11033-013-2600-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Accepted: 04/29/2013] [Indexed: 10/27/2022]
Abstract
The aim of the study was to analyze the consequence of silencing genes coding for the key subunits of the telomerase complex, i.e. TERT, TERC and TP1 in human breast cancer MCF7 and MDA-MB-231cells. The transfection was performed using Lipofectamine2000 and pooled siRNAs. The cytotoxic and/or antiproliferative effect of siRNA was measured by the SRB assay, the cell cycle was analysed by flow cytometry and DNA fragmentation by TUNEL analysis. Telomerase activity was assessed by TRAP, followed by PAGE and ELISA assays. Telomerase downregulation was also assessed using qPCR in order to estimate the changes in the expression profile of genes engaged in apoptosis. It was revealed that treatment of breast cancer cells with different siRNAs (100 nM) resulted in a cell type and time-dependent effects. The downregulation of telomerase subunits was followed by reduction of telomerase activity down to almost 60% compared to control cells. However, a significant effect was only observed when the TERT subunit was downregulated. Its silencing resulted in a significant (p<0.05) increase of apoptosis (over 10% in MCF7 and about 5% in MDA-MB-231 cells, corresponding to the Annexin V assay) and DNA fragmentation (almost 30% in MCF7 and over 25% in MDA-MB-231 cells). Interestingly, also several proapoptotic genes were induced after the downregulation of the key telomerase subunit, including Bax, Bik or caspase-1 and caspase-14, as well as NGFR and TNFSF10 which were upregulated twice and more.
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13
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hTERT: Another brick in the wall of cancer cells. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2013; 752:119-128. [DOI: 10.1016/j.mrrev.2012.12.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Revised: 11/28/2012] [Accepted: 12/10/2012] [Indexed: 01/06/2023]
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14
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Chen M, Xing LN. siRNA-mediated Inhibition of hTERC Enhances Radiosensitivity of Cervical Cancer. Asian Pac J Cancer Prev 2012; 13:5975-9. [DOI: 10.7314/apjcp.2012.13.12.5975] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Synergistic anticancer effect of RNAi and photothermal therapy mediated by functionalized single-walled carbon nanotubes. Biomaterials 2012; 34:262-74. [PMID: 23046752 DOI: 10.1016/j.biomaterials.2012.09.037] [Citation(s) in RCA: 129] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Accepted: 09/17/2012] [Indexed: 12/15/2022]
Abstract
Single-walled carbon nanotubes (SWNTs) are special nano-materials which exhibit interesting physical and chemical properties, presenting new opportunities for biomedical research and applications. In this study, we have successfully adopted a novel strategy to chemically functionalize SWNTs with polyethylenimine (PEI) through purification, oxidation, amination and polymerization, which were then bound by DSPE-PEG2000-Maleimide for further conjugation with the tumor targeting NGR (Cys-Asn-Gly-Arg-Cys-) peptide via the maleimide group and sulfhydryl group of cysteine, and finally hTERT siRNA was loaded to obtain a novel tumor targeting siRNA delivery system, designated as SWNT-PEI/siRNA/NGR. The results showed that SWNT-PEI/siRNA/NGR could efficiently cross cell membrane, induced more severe apoptosis and stronger suppression in proliferation of PC-3 cells in vitro. Furthermore, in tumor-bearing mice model the delivery system exhibited higher antitumor activity due to more accumulation in tumor without obvious toxicity in main organs. The combination of RNAi and near-infrared (NIR) photothermal therapy significantly enhanced the therapeutic efficacy. In conclusion, SWNT-PEI/siRNA/NGR is a novel and promising anticancer system by combining gene therapy and photothermal therapy.
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Lü MH, Liao ZL, Zhao XY, Fan YH, Lin XL, Fang DC, Guo H, Yang SM. hTERT-based therapy: a universal anticancer approach (Review). Oncol Rep 2012; 28:1945-52. [PMID: 22992764 DOI: 10.3892/or.2012.2036] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Accepted: 08/22/2012] [Indexed: 11/05/2022] Open
Abstract
Human telomerase reverse transcriptase (hTERT) has been identified as a major protein involved in aberrant cell proliferation, immortalization, metastasis and stemness maintenance in a majority of tumors, yet it has little or no expression in normal somatic cells. During the past few years, the development of hTERT-based therapies such as immunotherapy, suicide gene therapy and small-molecule interfering therapy have become critical and specific for eradicating all types of cancer. Here, current knowledge regarding hTERT and its involvement in various cancers and its role as a target of cancer therapies are reviewed. Additionally, hurdles to new cancer therapy development and new therapeutic opportunities are described, along with areas that require further investigation.
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Affiliation(s)
- Mu-Han Lü
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, PR China
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Tan J, Zhou X, Zhu H. hTERT-siRNA could potentiate the cytotoxic effect of gemcitabine to pancreatic cancer cells Bxpc-3. EXP CLIN TRANSPLANT 2012; 10:386-93. [PMID: 22757972 DOI: 10.6002/ect.2011.0157] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
OBJECTIVES This study sought to observe transfection of pancreatic cancer cells BxPC-3 with recombinant plasmid pSilencer4.1-cytomegalovirus neo-hTERT-siRNA and examine the combined effect of gemcitabine and siRNA inhibition of telomerase on pancreatic cancer cells. MATERIALS AND METHODS Transfected pancreatic cancer cells BxPC-3 with recombinant plasmid pSilencer4.1-cytomegalovirus neo-hTERT-siRNA were selected as target and divided into 9 groups: (1) T1 group (pSilencer4.1-CMV neo-hTERT1-siRNA), (2) T2 group (pSilencer4.1-CMV neo-hTERT2-siRNA), (3) L group (Lipofectamine) (4) M group (mismatch group pSilence4.1-CMV, as negative control), (5) C group (cell group without transfection), (6) blank and gemcitabine group, (7) mismatch siRNA and gemcitabine group, (8) hTERT1-siRNA and gemcitabine group, and (9) hTERT2-siRNA and gemcitabine group. Expression of hTERT mRNA was detected by reverse transcriptase polymerase chain reaction. Viability of cells was measured by colorimetric 3-(4,5-Dimethylthiazol-2-yl)-2, 5-Diphenyltetrazolium Bromide assay. Cell cycle and cell apoptosis were measured by flow cytometry. Expression of telomerase protein was measured by Western blot. RESULTS Compared with the L group, M group, and C group, expression of hTERT-mRNA and the level of telomerase protein in T1 and T2 group was down-regulated significantly (P < .05), viability of BxPC-3 cells decreased significantly (P < .05), the ratio of cells in G(0)/G(1) stage increased, the ratio of cells in the S stage and the G(2)/M stage decreased, and the ratio of apoptotic cells increased significantly in the T1 and T2 groups. Gemcitabine treatment had a comparable effect. Combination hTERT siRNA and gemcitabine killed twice as many cancer cells, showing a cumulative effect of the treatments. CONCLUSIONS Transfection of pancreatic cancer cells BxPC-3 with recombinant plasmid pSilencer4.1-CMV neo-hTERT-siRNA represents good RNAi silencing and anti-pancreatic cancer effects in vitro and could potentiate the cytotoxic effect of gemcitabine to pancreatic cancer cells.
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Affiliation(s)
- Jing Tan
- Division of Hepatopancreatobiliary, Second Affiliated Hospital, Kunming Medical College, Kunming 650101, China
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Xia W, Wang P, Lin C, Li Z, Gao X, Wang G, Zhao X. Bioreducible polyethylenimine-delivered siRNA targeting human telomerase reverse transcriptase inhibits HepG2 cell growth in vitro and in vivo. J Control Release 2012; 157:427-36. [DOI: 10.1016/j.jconrel.2011.10.011] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Revised: 09/21/2011] [Accepted: 10/11/2011] [Indexed: 11/30/2022]
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Zvereva MI, Shcherbakova DM, Dontsova OA. Telomerase: structure, functions, and activity regulation. BIOCHEMISTRY (MOSCOW) 2011; 75:1563-83. [PMID: 21417995 DOI: 10.1134/s0006297910130055] [Citation(s) in RCA: 110] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Telomerase is the enzyme responsible for maintenance of the length of telomeres by addition of guanine-rich repetitive sequences. Telomerase activity is exhibited in gametes and stem and tumor cells. In human somatic cells proliferation potential is strictly limited and senescence follows approximately 50-70 cell divisions. In most tumor cells, on the contrary, replication potential is unlimited. The key role in this process of the system of the telomere length maintenance with involvement of telomerase is still poorly studied. No doubt, DNA polymerase is not capable to completely copy DNA at the very ends of chromosomes; therefore, approximately 50 nucleotides are lost during each cell cycle, which results in gradual telomere length shortening. Critically short telomeres cause senescence, following crisis, and cell death. However, in tumor cells the system of telomere length maintenance is activated. Besides catalytic telomere elongation, independent telomerase functions can be also involved in cell cycle regulation. Inhibition of the telomerase catalytic function and resulting cessation of telomere length maintenance will help in restriction of tumor cell replication potential. On the other hand, formation of temporarily active enzyme via its intracellular activation or due to stimulation of expression of telomerase components will result in telomerase activation and telomere elongation that can be used for correction of degenerative changes. Data on telomerase structure and function are summarized in this review, and they are compared for evolutionarily remote organisms. Problems of telomerase activity measurement and modulation by enzyme inhibitors or activators are considered as well.
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Affiliation(s)
- M I Zvereva
- Faculty of Chemistry, Lomonosov Moscow State University, Russia.
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Liu X, Huang H, Wang J, Wang C, Wang M, Zhang B, Pan C. Dendrimers-delivered short hairpin RNA targeting hTERT inhibits oral cancer cell growth in vitro and in vivo. Biochem Pharmacol 2011; 82:17-23. [DOI: 10.1016/j.bcp.2011.03.017] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2011] [Revised: 03/16/2011] [Accepted: 03/17/2011] [Indexed: 10/18/2022]
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Min X, Zhou Q, Dong X, Wang Y, Xie L. Expression profile and regulation of telomerase reverse transcriptase on oxygen-induced retinal neovascularization. Curr Eye Res 2010; 36:135-42. [PMID: 21158588 DOI: 10.3109/02713683.2010.525679] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
PURPOSE Telomerase is critical for the control of replicative capacity, which plays a major role in proliferative retinal neovascularization. In this study, we investigated the expression profiles of telomerase reverse transcriptase (Tert) in a mouse model of oxygen-induced retinal neovascularization and explored the possibility of inhibiting a retinal Tert expression with small interfering RNAs (SiRNA) as a novel potential approach to suppress proliferative retinopathy. METHODS The mouse oxygen-induced retinal neovascularization model was used to examine expression profiles in different developmental phases and to assess the anti-angiogenic activity of Tert-SiRNA. Recombinant SiRNA plasmids were injected intravitreously into mice with or without pathological retinal neovascularization. Fluorescein angiography, vessel counting, and the expression levels of Tert mRNA and protein were used to evaluate the anti-angiogenic effects. RESULTS Retinal Tert expression, as assessed by both mRNA and protein levels, was significantly up-regulated during the proliferative phase of oxygen-induced retinal neovascularization. Intravitreous injection of Tert-SiRNA effectively suppressed the expression of Tert mRNA and proteins and inhibited retinal neovascularization, as confirmed by retinal flat angiography and vessel counting. CONCLUSIONS The expression of Tert was up-regulated during the development of oxygen-induced retinal neovascularization. Inhibiting Tert expression with SiRNA is effective in suppressing retinal neovascularization, suggesting that telomerase may be a potential therapeutic target for treating proliferative retinopathy.
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Affiliation(s)
- Xiaojie Min
- State Key Lab Cultivation Base, Shandong Provincial Key Lab of Ophthalmology, Shandong Eye Institute, Qingdao, China
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Maritz MF, Napier CE, Wen VW, MacKenzie KL. Targeting telomerase in hematologic malignancy. Future Oncol 2010; 6:769-89. [PMID: 20465390 DOI: 10.2217/fon.10.42] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Over the past two decades, it has become increasingly apparent that telomerase-mediated telomere maintenance plays a crucial role in hematopoiesis. Supporting evidence is underscored by recent findings of mutations in genes involved in telomerase-mediated telomere maintenance that contribute to the pathogenesis of bone marrow failure syndromes. More recently described telomere-independent functions of telomerase are also likely to contribute to both normal hematopoiesis and hematologic diseases. The high levels of telomerase detected in aggressive leukemias have fueled fervent investigation into diverse approaches to targeting telomerase in hematologic malignancies. Successful preclinical investigations that employed genetic strategies, oligonucleotides, small-molecule inhibitors and immunotherapy have resulted in a rapid translation to clinical trials. Further investigation of telomere-independent functions of telomerase and detailed preclinical studies of telomerase inhibition in both normal and malignant hematopoiesis will be invaluable for refining treatments to effectively and safely exploit telomerase as a therapeutic target in hematologic malignancies.
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Affiliation(s)
- Michelle F Maritz
- Children's Cancer Institute Australia for Medical Research, Lowy Cancer Research Centre, New South Wales, Australia
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Miura N, Osaki Y, Nagashima M, Kohno M, Yorozu K, Shomori K, Kanbe T, Oyama K, Kishimoto Y, Maruyama S, Noma E, Horie Y, Kudo M, Sakaguchi S, Hirooka Y, Ito H, Kawasaki H, Hasegawa J, Shiota G. A novel biomarker TERTmRNA is applicable for early detection of hepatoma. BMC Gastroenterol 2010; 10:46. [PMID: 20482774 PMCID: PMC2881114 DOI: 10.1186/1471-230x-10-46] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2009] [Accepted: 05/18/2010] [Indexed: 12/28/2022] Open
Abstract
Backgrounds We previously reported a highly sensitive method for serum human telomerase reverse transcriptase (hTERT) mRNA for hepatocellular carcinoma (HCC). α-fetoprotein (AFP) and des-γ-carboxy prothrombin (DCP) are good markers for HCC. In this study, we verified the significance of hTERTmRNA in a large scale multi-centered trial, collating quantified values with clinical course. Methods In 638 subjects including 303 patients with HCC, 89 with chronic hepatitis (CH), 45 with liver cirrhosis (LC) and 201 healthy individuals, we quantified serum hTERTmRNA using the real-time RT-PCR. We examined its sensitivity and specificity in HCC diagnosis, clinical significance, ROC curve analysis in comparison with other tumor markers, and its correlations with the clinical parameters using Pearson relative test and multivariate analyses. Furthermore, we performed a prospective and comparative study to observe the change of biomarkers, including hTERTmRNA in HCC patients receiving anti-cancer therapies. Results hTERTmRNA was demonstrated to be independently correlated with clinical parameters; tumor size and tumor differentiation (P < 0.001, each). The sensitivity/specificity of hTERTmRNA in HCC diagnosis showed 90.2%/85.4% for hTERT. hTERTmRNA proved to be superior to AFP, AFP-L3, and DCP in the diagnosis and underwent an indisputable change in response to therapy. The detection rate of small HCC by hTERTmRNA was superior to the other markers. Conclusions hTERTmRNA is superior to conventional tumor markers in the diagnosis and recurrence of HCC at an early stage.
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Affiliation(s)
- Norimasa Miura
- Department of Pathophysiological and Therapeutic Science, Tottori University, Japan.
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Miri-Moghaddam E, Deezagi A, Soheili ZS. Downregulation of telomerase activity in human promyelocytic cell line using RNA interference. Ann Hematol 2009; 88:1169-76. [PMID: 19415276 DOI: 10.1007/s00277-009-0748-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2008] [Accepted: 04/20/2009] [Indexed: 11/24/2022]
Abstract
Telomerase is a ribonucleoprotein complex. It consists of two main components, human telomerase reverse transcriptase (hTERT) and human telomerase RNA. High telomerase activity is present in most malignant cells, but it is barely detectable in majority of somatic cells. The direct correlation between telomerase reactivation and carcinogens has made hTERT a key target for anticancer therapeutic studies. In this study, for the first time, we evaluated the ability of the new generation of short interfering RNA (siRNA) to regulate telomerase activity in the human promyelocytic leukemia cell line (HL-60). Transient transfection cell line by hTERT siRNAs resulted in statistically significant suppression of hTERT messenger RNAs which were detected by quantitative real-time polymerase chain reaction, while the expressed hTERT protein levels were measured by flow cytometry. The results of telomeric repeat amplification protocol showed that telomerase activity was significantly reduced upon transfection of the HL-60 cell line with hTERT siRNAs. The results of this study showed that telomerase activity and cell proliferation were efficiently inhibited in the hTERT siRNA-treated leukemic cell line.
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Affiliation(s)
- E Miri-Moghaddam
- National Institute of Genetic Engineering and Biotechnology (NIGEB), Tehran, Iran
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siRNA inhibition of telomerase enhances the anti-cancer effect of doxorubicin in breast cancer cells. BMC Cancer 2009; 9:133. [PMID: 19416503 PMCID: PMC2691745 DOI: 10.1186/1471-2407-9-133] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2008] [Accepted: 05/05/2009] [Indexed: 01/14/2023] Open
Abstract
Background Doxorubicin is an effective breast cancer drug but is hampered by a severe, dose-dependent toxicity. Concomitant administration of doxorubicin and another cancer drug may be able to sensitize tumor cells to the cytotoxicity of doxorubicin and lowers the therapeutic dosage. In this study, we examined the combined effect of low-dose doxorubicin and siRNA inhibition of telomerase on breast cancer cells. We found that when used individually, both treatments were rapid and potent apoptosis inducers; and when the two treatments were combined, we observed an enhanced and sustained apoptosis induction in breast cancer cells. Methods siRNA targeting the mRNA of the protein component of telomerase, the telomerase reverse transcriptase (hTERT), was transfected into two breast cancer cell lines. The siRNA inhibition was confirmed by RT-PCR and western blot on hTERT mRNA and protein levels, respectively, and by measuring the activity level of telomerase using the TRAP assay. The effect of the hTERT siRNA on the tumorigenicity of the breast cancer cells was also studied in vivo by injection of the siRNA-transfected breast cancer cells into nude mice. The effects on cell viability, apoptosis and senescence of cells treated with hTERT siRNA, doxorubicin, and the combined treatment of doxorubicin and hTERT siRNA, were examined in vitro by MTT assay, FACS and SA-β-galactosidase staining. Results The hTERT siRNA effectively knocked down the mRNA and protein levels of hTERT, and reduced the telomerase activity to 30% of the untreated control. In vivo, the tumors induced by the hTERT siRNA-transfected cells were of reduced sizes, indicating that the hTERT siRNA also reduced the tumorigenic potential of the breast cancer cells. The siRNA treatment reduced cell viability by 50% in breast cancer cells within two days after transfection, while 0.5 μM doxorubicin treatment had a comparable effect but with a slower kinetics. The combination of hTERT siRNA and 0.5 μM doxorubicin killed twice as many cancer cells, showing a cumulative effect of the two treatments. Conclusion The study demonstrated the potential of telomerase inhibition as an effective treatment for breast cancer. When used in conjunction to doxorubicin, it could potentiate the cytotoxic effect of the drug to breast cancer cells.
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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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Folini M, Pennati M, Zaffaroni N. RNA interference-mediated validation of genes involved in telomere maintenance and evasion of apoptosis as cancer therapeutic targets. Methods Mol Biol 2009; 487:303-30. [PMID: 19301654 DOI: 10.1007/978-1-60327-547-7_15] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The discovery of new cancer-related therapeutic targets is mainly based on the identification of genes involved in pathways selectively exploited in cancer cells, including those leading to unlimited replicative potential, evasion of apoptosis, angiogenesis, tissue invasion and metastatic spread. Potentially, a gene--or a gene product--is recognized as a cancer target whether its modulation in experimental models can specifically modify or revert the cancer phenotype. As soon as RNA interference (RNAi)--a natural gene silencing mechanism--was demonstrated in mammalian cells, it rapidly became an essential means for gene knockdown in preclinical models, making it possible to define the role of several human genes and to identify those specifically involved in the onset and progression of cancer. Owing to its powerful gene-silencing properties, RNAi has been proposed as a useful tool to validate new therapeutic targets and to develop innovative anticancer therapies. This chapter summarizes the findings from recent studies relying on the use of RNAi-based approaches to functionally validate therapeutic targets related to two tumor hallmarks: the unlimited replicative potential (i.e., activation of telomere maintenance mechanisms) and evasion of apoptosis (i.e., up-regulation of anti-apoptotic factors).
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Affiliation(s)
- Marco Folini
- Dipartimento di Oncologia Sperimentale e Laboratori, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
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Zhou P, Fang DC, Chen B, Mao GP, Liu WW, Cao CP, Bu XH, Zhang QJ. Cloning of a group of telomere-associated proteins. Shijie Huaren Xiaohua Zazhi 2008; 16:1507-1512. [DOI: 10.11569/wcjd.v16.i14.1507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To elucidate the biological function and molecular mechanism of telomerase in immortal and/or tumor cells.
METHODS: Based on the principle of the yeast two-hybrid technology, the recombinant of human telomerase catalytic subunit bait fusion gene was constructed by DNA recombination technique, which was employed to screen cDNA libraries. The positive clones were confirmed by β-galactosidase colony-lift filter assay and furthermore the obtained plasmids cDNA sequences were compared with the isogenous sequences in GenBank.
RESULTS: The gene phenotypes of AH109 and Y187 yeast strains were stable and there was no leak expression of His. The recombinant of human telomerase catalytic subunit bait fusion gene, which was named as pGBKT7-hTERT, was constructed, and its bait fusion protein had no toxic effects on AH109 yeast cells and no activation effect on the autonomous reporter gene LacZ. Twenty-eight Ade+, Leu+, Trp+, and His+ clones were screened from the cDNA libraries and 12 Ade+, His+ and LacZ+ clones were obtained by the print analysis of β-galactosidase colony-lift filter assay. Of the 12 positive clones, 5 library plasmids possessed the effect of autonomously activating the reporter gene, so they were removed. There were 7 true positive clones among the library plasmids, 2 of which were found repeated after sequencing. The six obtained plasmids cDNA sequences were compared with the isogenous sequences in GenBank by Blast software via Internet. Finally, 6 recorded cDNA sequences were obtained, including T-STAR, PAWR, I-1, SMARCB1, LOXL3 and HKR3.
CONCLUSION: The 6 obtained telomere-associated proteins may help us understand the structure of telomerase holoenzyme and the biological function and molecular mechanism of telomerase in tumor and/or immortal cells, providing a theoretical basis for the tumor genesis, aging and prevention.
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Folini M, Bandiera R, Millo E, Gandellini P, Sozzi G, Gasparini P, Longoni N, Binda M, Daidone MG, Berg K, Zaffaroni N. Photochemically enhanced delivery of a cell-penetrating peptide nucleic acid conjugate targeting human telomerase reverse transcriptase: effects on telomere status and proliferative potential of human prostate cancer cells. Cell Prolif 2007; 40:905-20. [PMID: 18021178 DOI: 10.1111/j.1365-2184.2007.00470.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
OBJECTIVES Peptide nucleic acids (PNAs) are DNA mimics that have been demonstrated to be efficient antisense/antigene tools in cell-free systems. However, their potential as in vivo regulators of gene expression has been hampered by their poor uptake by living cells, and strategies need to be developed for their intracellular delivery. This study has aimed to demonstrate the possibility (i) of efficiently delivering a PNA, which targets mRNA of the catalytic component of human telomerase reverse transcriptase (hTERT), into DU145 prostate cancer cells through a combined approach based on conjugation of the PNA to Tat internalizing peptide (hTERT-PNA-Tat) and subsequent photochemical internalization, and (ii) to interfere with telomerase function. MATERIALS AND METHODS Treated cells were analysed for telomerase activity, hTERT expression, growth rate, ability to undergo apoptosis and telomere status. RESULTS After exposure to light, DU145 cells treated with hTERT-PNA-Tat and the photosensitiser TPPS2a showed dose-dependent inhibition of telomerase activity, which was accompanied by marked reduction of hTERT protein expression. A dose-dependent decline in DU145 cell population growth and induction of caspase-dependent apoptosis were also observed from 48 h after treatment. Such an antiproliferative effect was associated with the presence of telomeric dysfunction, as revealed by cytogenetic analysis, in the absence of telomere shrinkage, and with induction of DNA damage response as suggested by the increased expression of gamma-H2AX. CONCLUSIONS Our results (i) indicate photochemical internalization as an efficient approach for intracellular delivery of chimaeric PNAs, and (ii) corroborate earlier evidence suggesting pro-survival and anti-apoptotic roles of hTERT, which are independent of its ability to maintain telomere length.
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Affiliation(s)
- M Folini
- Department of Experimental Oncology, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
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Tárkányi I, Aradi J. Pharmacological intervention strategies for affecting telomerase activity: future prospects to treat cancer and degenerative disease. Biochimie 2007; 90:156-72. [PMID: 17945408 DOI: 10.1016/j.biochi.2007.09.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2007] [Accepted: 09/04/2007] [Indexed: 12/20/2022]
Abstract
Telomerase enzyme is a ribonucleoprotein maintaining the length of the telomeres by adding G-rich repeats to the end of the eukaryotic chromosomes. Normal human somatic cells, cultured in vitro, have a strictly limited proliferative potential undergoing senescence after about 50-70 population doublings. In contrast, most of the tumor cells have unlimited replicative potential. Although the mechanisms of immortalization are not understood completely at a genetic level, the key role of the telomere/telomerase system in the process is clear. The DNA replication machinery is not able to replicate fully the DNA at the very end of the chromosomes; therefore, about 50-200 nucleotides are lost during each of the replication cycles resulting in a gradual decrease of telomere length. Critically short telomere induces senescence, subsequent crisis and cell death. In tumor cells, however, the telomerase enzyme prevents the formation of critically short telomeres, adding GGTTAG repeats to the 3' end of the chromosomes immortalizing the cells. Immortality is one of the hallmarks of cancer. Besides the catalytic activity dependent telomere maintenance, catalytic activity-independent effects of telomerase may also be involved in the regulation of cell cycle. The telomere/telomerase system offers two possibilities to intervene the proliferative activity of the cell: (1) inhibition the telomere maintenance by inhibiting the telomerase activity; (2) activating the residual telomerase enzyme or inducing telomerase expression. Whilst the former approach could abolish the limitless replicative potential of malignant cells, the activation of telomerase might be utilized for treating degenerative diseases. Here, we review the current status of telomerase therapeutics, summarizing the activities of those pharmacological agents which either inhibit or activate the enzyme. We also discuss the future opportunities and challenges of research on pharmacological intervention of telomerase activity.
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Affiliation(s)
- I Tárkányi
- 3rd Department of Internal Medicine, University of Debrecen, 22 Moricz Zsigmond Krt., Debrecen 4004, Hungary
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