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Guarnaccia L, Navone SE, Begani L, Barilla E, Garzia E, Campanella R, Miozzo M, Fontana L, Alotta G, Cordiglieri C, Gaudino C, Schisano L, Ampollini A, Riboni L, Locatelli M, Marfia G. Testing calpain inhibition in tumor endothelial cells: novel targetable biomarkers against glioblastoma malignancy. Front Oncol 2024; 14:1355202. [PMID: 39156707 PMCID: PMC11327812 DOI: 10.3389/fonc.2024.1355202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Accepted: 07/01/2024] [Indexed: 08/20/2024] Open
Abstract
Introduction Glioblastoma IDH-wildtype (GBM) is the most malignant brain tumor in adults, with a poor prognosis of approximately 15 months after diagnosis. Most patients suffer from a recurrence in <1 year, and this renders GBM a life-threatening challenge. Among molecular mechanisms driving GBM aggressiveness, angiogenesis mediated by GBM endothelial cells (GECs) deserves consideration as a therapeutic turning point. In this scenario, calpains, a family of ubiquitously expressed calcium-dependent cysteine proteases, emerged as promising targets to be investigated as a novel therapeutic strategy and prognostic tissue biomarkers. Methods To explore this hypothesis, GECs were isolated from n=10 GBM biopsies and characterized phenotypically by immunofluorescence. The expression levels of calpains were evaluated by qRT-PCR and Western blot, and their association with patients' prognosis was estimated by Pearson correlation and Kaplan-Meier survival analysis. Calpain targeting efficacy was assessed by a time- and dose-dependent proliferation curve, MTT assay for viability, caspase-3/7 activity, migration and angiogenesis in vitro, and gene and protein expression level modification. Results Immunofluorescence confirmed the endothelial phenotype of our primary GECs. A significant overexpression was observed for calpain-1/2/3 (CAPN) and calpain-small-subunits-1/2 (CAPNS1), whereas calpastatin gene, the calpain natural inhibitor, was reported to be downregulated. A significant negative correlation was observed between CAPN1/CAPNS1 and patient overall survival. GEC challenging revealed that the inhibition of calpain-1 exerts the strongest proapoptotic efficacy, so GEC mortality reached the 80%, confirmed by the increased activity of caspase-3/7. Functional assays revealed a strong affection of in vitro migration and angiogenesis. Gene and protein expression proved a downregulation of MAPK, VEGF/VEGFRs, and Bcl-2, and an upregulation of caspases and Bax-family mediators. Conclusion Overall, the differential expression of calpains and their correlation with patient survival suggest a novel promising target pathway, whose blockade showed encouraging results toward precision medicine strategies.
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Affiliation(s)
- Laura Guarnaccia
- Laboratory of Experimental Neurosurgery and Cell Therapy, Neurosurgery Unit, Foundation IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Stefania Elena Navone
- Laboratory of Experimental Neurosurgery and Cell Therapy, Neurosurgery Unit, Foundation IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Laura Begani
- Laboratory of Experimental Neurosurgery and Cell Therapy, Neurosurgery Unit, Foundation IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy
| | | | - Emanuele Garzia
- Reproductive Medicine Unit, Department of Mother and Child, San Paolo Hospital Medical School, ASST Santi Paolo e Carlo, Milan, Italy
- Aerospace Medicine Institute “A. Mosso”, Italian Air Force, Milan, Italy
| | - Rolando Campanella
- Laboratory of Experimental Neurosurgery and Cell Therapy, Neurosurgery Unit, Foundation IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Monica Miozzo
- Medical Genetics, Department of Health Sciences, Università Degli Studi di Milano, Milan, Italy
- Medical Genetics Unit, ASST Santi Paolo e Carlo, Milan, Italy
| | - Laura Fontana
- Medical Genetics, Department of Health Sciences, Università Degli Studi di Milano, Milan, Italy
- Medical Genetics Unit, ASST Santi Paolo e Carlo, Milan, Italy
| | | | - Chiara Cordiglieri
- Istituto Nazionale Genetica Molecolare Romeo ed Enrica Invernizzi, Milan, Italy
| | - Chiara Gaudino
- Department of Neuroradiology, Azienda Ospedaliero-Universitaria Policlinico Umberto I, Rome, Italy
| | - Luigi Schisano
- Laboratory of Experimental Neurosurgery and Cell Therapy, Neurosurgery Unit, Foundation IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Antonella Ampollini
- Laboratory of Experimental Neurosurgery and Cell Therapy, Neurosurgery Unit, Foundation IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy
| | | | - Marco Locatelli
- Laboratory of Experimental Neurosurgery and Cell Therapy, Neurosurgery Unit, Foundation IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy
- Department of Medical-Surgical Physiopathology and Transplantation, University of Milan, Milan, Italy
| | - Giovanni Marfia
- Laboratory of Experimental Neurosurgery and Cell Therapy, Neurosurgery Unit, Foundation IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy
- Aerospace Medicine Institute “A. Mosso”, Italian Air Force, Milan, Italy
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Tang C, Chen L, Xu Y, Huang L, Zeng Z. Prediction of TERT mutation status in gliomas using conventional MRI radiogenomic features. Front Neurol 2024; 15:1439598. [PMID: 39131044 PMCID: PMC11310134 DOI: 10.3389/fneur.2024.1439598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2024] [Accepted: 07/15/2024] [Indexed: 08/13/2024] Open
Abstract
Objective Telomerase reverse transcriptase (TERT) promoter mutation status in gliomas is a key determinant of treatment strategy and prognosis. This study aimed to analyze the radiogenomic features and construct radiogenomic models utilizing medical imaging techniques to predict the TERT promoter mutation status in gliomas. Methods This was a retrospective study of 304 patients with gliomas. T1-weighted contrast-enhanced, apparent diffusion coefficient, and diffusion-weighted imaging MRI sequences were used for radiomic feature extraction. A total of 3,948 features were extracted from MRI images using the FAE software. These included 14 shape features, 18 histogram features, 24 gray level run length matrix, 14 gray level dependence matrix, 16 gray level run length matrix, 16 gray level size zone matrix (GLSZM), 5 neighboring gray tone difference matrix, and 744 wavelet transforms. The dataset was randomly divided into training and testing sets in a ratio of 7:3. Three feature selection methods and six classification algorithms were used to model the selected features. Predictive performance was evaluated using receiver operating characteristic curve analysis. Results Among the evaluated classification algorithms, the combination model of recursive feature elimination (RFE) with linear regression (LR) using six features showed the best diagnostic performance (area under the curve: 0.733, 0.562, and 0.633 in the training, validation, and testing sets, respectively). The next best-performing models were naive Bayes, linear discriminant analysis, autoencoder, and support vector machine. Regarding the three feature selection algorithms, RFE showed the most consistent performance, followed by relief and ANOVA. T1-enhanced entropy and GLSZM derived from T1-enhanced images were identified as the most critical radiomics features for distinguishing TERT promoter mutation status. Conclusion The LR and LRLasso models, mainly based on T1-enhanced entropy and GLSZM, showed good predictive ability for TERT promoter mutations in gliomas using radiomics models.
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Affiliation(s)
| | | | | | | | - Zisan Zeng
- Department of Radiology, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
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Chen L, Chen R, Li T, Huang L, Tang C, Li Y, Zeng Z. MRI radiomics model for predicting TERT promoter mutation status in glioblastoma. Brain Behav 2023; 13:e3324. [PMID: 38054695 PMCID: PMC10726789 DOI: 10.1002/brb3.3324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 09/05/2023] [Accepted: 10/31/2023] [Indexed: 12/07/2023] Open
Abstract
BACKGROUND AND PURPOSE The presence of TERT promoter mutations has been associated with worse prognosis and resistance to therapy for patients with glioblastoma (GBM). This study aimed to determine whether the combination model of different feature selections and classification algorithms based on multiparameter MRI can be used to predict TERT subtype in GBM patients. METHODS A total of 143 patients were included in our retrospective study, and 2553 features were obtained. The datasets were randomly divided into training and test sets in a ratio of 7:3. The synthetic minority oversampling technique was used to achieve data balance. The Pearson correlation coefficients were used for dimension reduction. Three feature selections and five classification algorithms were used to model the selected features. Finally, 10-fold cross validation was applied to the training dataset. RESULTS A model with eight features generated by recursive feature elimination (RFE) and linear discriminant analysis (LDA) showed the greatest diagnostic performance (area under the curve values for the training, validation, and testing sets: 0.983, 0.964, and 0.926, respectively), followed by relief and random forest (RF), analysis of variance and RF. Furthermore, the relief was the optimal feature selection for separately evaluating those five classification algorithms, and RF was the most preferable algorithm for separately assessing the three feature selectors. ADC entropy was the parameter that made the greatest contribution to the discrimination of TERT mutations. CONCLUSIONS Radiomics model generated by RFE and LDA mainly based on ADC entropy showed good performance in predicting TERT promoter mutations in GBM.
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Affiliation(s)
- Ling Chen
- Department of RadiologyThe First Affiliated Hospital of Guangxi Medical UniversityNanningGuangxiChina
- Department of RadiologyLiuzhou Worker's HospitalThe Fourth Affiliated HospitalGuangxi Medical UniversityNanningGuangxiChina
| | - Runrong Chen
- Department of RadiologyThe First Affiliated Hospital of Guangxi Medical UniversityNanningGuangxiChina
| | - Tao Li
- Department of RadiologyLiuzhou Worker's HospitalThe Fourth Affiliated HospitalGuangxi Medical UniversityNanningGuangxiChina
| | - Lizhao Huang
- Department of RadiologyLiuzhou Worker's HospitalThe Fourth Affiliated HospitalGuangxi Medical UniversityNanningGuangxiChina
| | - Chuyun Tang
- Department of RadiologyThe First Affiliated Hospital of Guangxi Medical UniversityNanningGuangxiChina
| | - Yao Li
- Department of NeurosurgeryLiuzhou Worker's HospitalThe Fourth Affiliated HospitalGuangxi Medical UniversityNanningGuangxiChina
| | - Zisan Zeng
- Department of RadiologyThe First Affiliated Hospital of Guangxi Medical UniversityNanningGuangxiChina
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Knockdown of the stem cell marker Musashi-1 inhibits endometrial cancer growth and sensitizes cells to radiation. Stem Cell Res Ther 2022; 13:212. [PMID: 35619161 PMCID: PMC9137084 DOI: 10.1186/s13287-022-02891-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 04/02/2022] [Indexed: 11/22/2022] Open
Abstract
Background Endometrial carcinoma is the most common gynecological cancer in Europe. Musashi-1 is known to be a key regulator of endometrial cancer stem cells and a negative prognostic marker. In the present study, we aimed to understand growth and gene expression patterns in endometrial carcinoma after Musashi-1 knockdown in vitro and in vivo. Changes in therapeutic resistance were also assessed.
Methods First, we performed analyses to understand Musashi-1 expression patterns using The Cancer Genome Atlas database. We then proceeded to assess effects of small interfering RNA-based Musashi-1 targeting in two endometrial carcinoma cell lines, Ishikawa and KLE. After quantifying baseline changes in cell metabolism, we used MTT tests to assess chemotherapy effects and colony formation assays to understand changes in radioresistance. For mechanistic study, we used quantitative polymerase chain reaction (qPCR) and western blotting of key Musashi-1 target genes and compared results to primary tissue database studies. Finally, xenograft experiments in a mouse model helped understand in vivo effects of Musashi-1 knockdown. Results Musashi-1 is aberrantly expressed in primary tumor tissues. In vitro, silencing of Musashi-1 resulted in a strong decline in cell proliferation and radioresistance, while chemoresistance remained unchanged. Loss of Musashi-1 led to downregulation of telomerase, DNA-dependent protein kinase, the Notch pathway and overexpression of cyclin-dependent kinase inhibitor p21, the latter of which we identified as a key mediator of Msi-1 knockdown-related anti-proliferative signaling. In vivo, the anti-proliferative effect was confirmed, with Msi-1 knockdown tumors being about 40% reduced in size. Conclusions Musashi-1 knockdown resulted in a strong decrease in endometrial cancer proliferation and a loss of radioresistance, suggesting therapeutic potential. Supplementary Information The online version contains supplementary material available at 10.1186/s13287-022-02891-3.
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Seidel C, Heider S, Hau P, Glasow A, Dietzsch S, Kortmann RD. Radiotherapy in Medulloblastoma-Evolution of Treatment, Current Concepts and Future Perspectives. Cancers (Basel) 2021; 13:cancers13235945. [PMID: 34885055 PMCID: PMC8657317 DOI: 10.3390/cancers13235945] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Revised: 11/21/2021] [Accepted: 11/23/2021] [Indexed: 11/17/2022] Open
Abstract
Simple Summary Craniospinal irradiation (CSI) is the backbone of medulloblastoma treatment and the first treatment to achieve a cure in many patients. Within the last decades, significant efforts have been made to enhance efficacy in combination with chemotherapy. With this approach, a majority of low- and standard-risk patients can be cured. In parallel, many clinical trials have dealt with CSI-dose reduction and reduction of boost volume in order to decrease long-term toxicity, particularly neurotoxicity. Within these trials, standardized quality assurance has helped to increase the accuracy of treatment and improve prognosis. More recently, advances of radiotherapy techniques such as proton treatment allowed for better sparing of healthy tissue in order to further diminish detrimental long-term effects. Major future challenges are the adaption of radiotherapy regimens to different molecularly defined disease groups alone or together with new targeted agents. Moreover, and even more importantly, innovative combinatorial treatments are needed in high- and very-high risk situations. Abstract Medulloblastoma is the most frequent malignant brain tumor in children. During the last decades, the therapeutic landscape has changed significantly with craniospinal irradiation as the backbone of treatment. Survival times have increased and treatments were stratified according to clinical and later molecular risk factors. In this review, current evidence regarding the efficacy and toxicity of radiotherapy in medulloblastoma is summarized and discussed mainly based on data of controlled trials. Current concepts and future perspectives based on current risk classification are outlined. With the introduction of CSI, medulloblastoma has become a curable disease. Due to combination with chemotherapy, survival rates have increased significantly, allowing for a reduction in radiation dose and a decrease of toxicity in low- and standard-risk patients. Furthermore, modern radiotherapy techniques are able to avoid side effects in a fragile patient population. However, high-risk patients remain with relevant mortality and many patients still suffer from treatment related toxicity. Treatment needs to be continually refined with regard to more efficacious combinatorial treatment in the future.
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Affiliation(s)
- Clemens Seidel
- Department of Radiation Oncology, University Hospital Leipzig, 04103 Leipzig, Germany; (S.H.); (A.G.); (S.D.); (R.-D.K.)
- Correspondence:
| | - Sina Heider
- Department of Radiation Oncology, University Hospital Leipzig, 04103 Leipzig, Germany; (S.H.); (A.G.); (S.D.); (R.-D.K.)
| | - Peter Hau
- Wilhelm Sander-NeuroOncology Unit, Regensburg University Hospital, 93053 Regensburg, Germany;
| | - Annegret Glasow
- Department of Radiation Oncology, University Hospital Leipzig, 04103 Leipzig, Germany; (S.H.); (A.G.); (S.D.); (R.-D.K.)
| | - Stefan Dietzsch
- Department of Radiation Oncology, University Hospital Leipzig, 04103 Leipzig, Germany; (S.H.); (A.G.); (S.D.); (R.-D.K.)
| | - Rolf-Dieter Kortmann
- Department of Radiation Oncology, University Hospital Leipzig, 04103 Leipzig, Germany; (S.H.); (A.G.); (S.D.); (R.-D.K.)
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Mechanism of Human Telomerase Reverse Transcriptase ( hTERT) Regulation and Clinical Impacts in Leukemia. Genes (Basel) 2021; 12:genes12081188. [PMID: 34440361 PMCID: PMC8392866 DOI: 10.3390/genes12081188] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 05/09/2021] [Accepted: 05/17/2021] [Indexed: 01/03/2023] Open
Abstract
The proliferative capacity and continuous survival of cells are highly dependent on telomerase expression and the maintenance of telomere length. For this reason, elevated expression of telomerase has been identified in virtually all cancers, including leukemias; however, it should be noted that expression of telomerase is sometimes observed later in malignant development. This time point of activation is highly dependent on the type of leukemia and its causative factors. Many recent studies in this field have contributed to the elucidation of the mechanisms by which the various forms of leukemias increase telomerase activity. These include the dysregulation of telomerase reverse transcriptase (TERT) at various levels which include transcriptional, post-transcriptional, and post-translational stages. The pathways and biological molecules involved in these processes are also being deciphered with the advent of enabling technologies such as next-generation sequencing (NGS), ribonucleic acid sequencing (RNA-Seq), liquid chromatography-mass spectrometry (LCMS/MS), and many others. It has also been established that TERT possess diagnostic value as most adult cells do not express high levels of telomerase. Indeed, studies have shown that prognosis is not favorable in patients who have leukemias expressing high levels of telomerase. Recent research has indicated that targeting of this gene is able to control the survival of malignant cells and therefore offers a potential treatment for TERT-dependent leukemias. Here we review the mechanisms of hTERT regulation and deliberate their association in malignant states of leukemic cells. Further, we also cover the clinical implications of this gene including its use in diagnostic, prognostic, and therapeutic discoveries.
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Ghareghomi S, Ahmadian S, Zarghami N, Hemmati S. hTERT-molecular targeted therapy of ovarian cancer cells via folate-functionalized PLGA nanoparticles co-loaded with MNPs/siRNA/wortmannin. Life Sci 2021; 277:119621. [PMID: 34004255 DOI: 10.1016/j.lfs.2021.119621] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 05/02/2021] [Accepted: 05/08/2021] [Indexed: 12/15/2022]
Abstract
Effective telomerase-molecular targeted cancer therapy might be a promising approach for the efficient treatment of ovarian cancer. Therefore, folate-functionalized PLGA nanoparticles (NPs) were co-loaded with hTERT siRNA, Wortmannin (Wtmn), as a potent PI3K inhibitor, and magnetic nanoparticle (MNPs) as a theranostic agent to gain a multifunctional NPs for targeted drug delivery as well as molecular targeted therapy. 1HNMR, FTIR, DLS, FE-SEM and TEM were applied to characterize the synthesized NPs. In vitro discharge pattern for siRNA and Wtmn from the dual drug-loaded NPs showed an early fast release followed by a constant release up to 200 h. According to the MRI analysis, by increasing the concentration of Fe3O4 in NPs, the weaker T2 signal intensity was enhanced, and a considerable contrast was detected in the MRI images. MTT assay and median-effect analysis showed that the Wtmn/siRNA-loaded MNPs-PLGA-F2 NPs display the most synergistic cytotoxicity on the SKOV-3 ovarian cancer cells. Moreover, the Wtmn/siRNA-loaded MNPs-PLGA-FA NPs could significantly reduce the expression of hTERT, AKT, and p-AKT than the single drug-encapsulated NPs (P < 0.05). Taken together, the findings showed that the multifunctional NPs relying on combinatorial therapy might have considerable potential for effective telomerase-molecular targeted therapy of ovarian cancer.
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Affiliation(s)
- Somayyeh Ghareghomi
- Department of Biochemistry, Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran
| | - Shahin Ahmadian
- Department of Biochemistry, Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran.
| | - Nosratollah Zarghami
- Department of Clinical Biochemistry and Laboratory Medicine, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Salar Hemmati
- Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
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Romaniuk-Drapała A, Totoń E, Konieczna N, Machnik M, Barczak W, Kowal D, Kopczyński P, Kaczmarek M, Rubiś B. hTERT Downregulation Attenuates Resistance to DOX, Impairs FAK-Mediated Adhesion, and Leads to Autophagy Induction in Breast Cancer Cells. Cells 2021; 10:cells10040867. [PMID: 33920284 PMCID: PMC8068966 DOI: 10.3390/cells10040867] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 04/06/2021] [Accepted: 04/07/2021] [Indexed: 12/13/2022] Open
Abstract
Telomerase is known to contribute to telomere maintenance and to provide cancer cell immortality. However, numerous reports are showing that the function of the enzyme goes far beyond chromosome ends. The study aimed to explore how telomerase downregulation in MCF7 and MDA-MB-231 breast cancer cells affects their ability to survive. Consequently, sensitivity to drug resistance, proliferation, and adhesion were assessed. The lentiviral-mediated human telomerase reverse transcriptase (hTERT) downregulation efficiency was performed at gene expression and protein level using qPCR and Western blot, respectively. Telomerase activity was evaluated using the Telomeric Repeat Amplification Protocol (TRAP) assay. The study revealed that hTERT downregulation led to an increased sensitivity of breast cancer cells to doxorubicin which was demonstrated in MTT and clonogenic assays. During a long-term doubling time assessment, a decreased population doubling level was observed. Interestingly, it did not dramatically affect cell cycle distribution. hTERT downregulation was accompanied by an alteration in β1-integrin- and by focal adhesion kinase (FAK)-driven pathways together with the reduction of target proteins phosphorylation, i.e., paxillin and c-Src. Additionally, autophagy activation was observed in MDA-MB-231 cells manifested by alternations in Atg5, Beclin 1, LC3II/I ratio, and p62. These results provide new evidence supporting the possible therapeutic potential of telomerase downregulation leading to induction of autophagy and cancer cells elimination.
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Affiliation(s)
- Aleksandra Romaniuk-Drapała
- Department of Clinical Chemistry and Molecular Diagnostics, Poznan University of Medical Sciences, 49 Przybyszewskiego St., 60-355 Poznań, Poland; (A.R.-D.); (E.T.); (N.K.); (D.K.)
| | - Ewa Totoń
- Department of Clinical Chemistry and Molecular Diagnostics, Poznan University of Medical Sciences, 49 Przybyszewskiego St., 60-355 Poznań, Poland; (A.R.-D.); (E.T.); (N.K.); (D.K.)
| | - Natalia Konieczna
- Department of Clinical Chemistry and Molecular Diagnostics, Poznan University of Medical Sciences, 49 Przybyszewskiego St., 60-355 Poznań, Poland; (A.R.-D.); (E.T.); (N.K.); (D.K.)
| | - Marta Machnik
- Department of Cancer Immunology, Poznan University of Medical Sciences, 60-806 Poznan, Poland;
| | - Wojciech Barczak
- Department of Head and Neck Surgery, Poznan University of Medical Sciences, The Greater Poland Cancer Centre, 61-866 Poznan, Poland;
| | - Dagmar Kowal
- Department of Clinical Chemistry and Molecular Diagnostics, Poznan University of Medical Sciences, 49 Przybyszewskiego St., 60-355 Poznań, Poland; (A.R.-D.); (E.T.); (N.K.); (D.K.)
| | - 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;
| | - Mariusz Kaczmarek
- Department of Immunology, Chair of Clinical Immunology, Poznań University of Medical Sciences, 5D Rokietnicka St., 60-806 Poznań, Poland;
| | - Błażej Rubiś
- Department of Clinical Chemistry and Molecular Diagnostics, Poznan University of Medical Sciences, 49 Przybyszewskiego St., 60-355 Poznań, Poland; (A.R.-D.); (E.T.); (N.K.); (D.K.)
- Correspondence: ; Tel.: +48-61-869-14-27
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Abstract
Glioblastoma is a highly lethal form of brain cancer with no current treatment options that substantially improve patient outcomes. A key therapeutic challenge is the identification of methods that reduce tumor burden while leaving normal cells unaffected. We show that TERT-promoter mutations, common in glioblastoma, lead to TERT reactivation through increased binding of GABPB1L-isoform–containing transcription factor complexes. In turn, we find that cancer-cell–specific inhibition of TERT through GABPB1L reduction results in near-term anti-growth effects and an impaired DNA damage response that profoundly increase the sensitivity of glioblastoma tumors to frontline chemotherapy. Our results thus provide rationale for GABPB1L inhibition combined with temozolomide chemotherapy treatment as a promising therapeutic strategy for glioblastoma. Most glioblastomas (GBMs) achieve cellular immortality by acquiring a mutation in the telomerase reverse transcriptase (TERT) promoter. TERT promoter mutations create a binding site for a GA binding protein (GABP) transcription factor complex, whose assembly at the promoter is associated with TERT reactivation and telomere maintenance. Here, we demonstrate increased binding of a specific GABPB1L-isoform–containing complex to the mutant TERT promoter. Furthermore, we find that TERT promoter mutant GBM cells, unlike wild-type cells, exhibit a critical near-term dependence on GABPB1L for proliferation, notably also posttumor establishment in vivo. Up-regulation of the protein paralogue GABPB2, which is normally expressed at very low levels, can rescue this dependence. More importantly, when combined with frontline temozolomide (TMZ) chemotherapy, inducible GABPB1L knockdown and the associated TERT reduction led to an impaired DNA damage response that resulted in profoundly reduced growth of intracranial GBM tumors. Together, these findings provide insights into the mechanism of cancer-specific TERT regulation, uncover rapid effects of GABPB1L-mediated TERT suppression in GBM maintenance, and establish GABPB1L inhibition in combination with chemotherapy as a therapeutic strategy for TERT promoter mutant GBM.
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Bajaj S, Kumar MS, Peters GJ, Mayur YC. Targeting telomerase for its advent in cancer therapeutics. Med Res Rev 2020; 40:1871-1919. [PMID: 32391613 DOI: 10.1002/med.21674] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2019] [Revised: 04/19/2020] [Accepted: 04/21/2020] [Indexed: 12/24/2022]
Abstract
Telomerase has emerged as an important primary target in anticancer therapy. It is a distinctive reverse transcriptase enzyme, which extends the length of telomere at the 3' chromosomal end, and uses telomerase reverse transcriptase (TERT) and telomerase RNA template-containing domains. Telomerase has a vital role and is a contributing factor in human health, mainly affecting cell aging and cell proliferation. Due to its unique feature, it ensures unrestricted cell proliferation in malignancy and plays a major role in cancer disease. The development of telomerase inhibitors with increased specificity and better pharmacokinetics is being considered to design and develop newer potent anticancer agents. Use of natural and synthetic compounds for the inhibition of telomerase activity can lead to an opening of new vistas in cancer treatment. This review details about the telomerase biochemistry, use of natural and synthetic compounds; vaccines and oncolytic virus in therapy that suppress the telomerase activity. We have discussed structure-activity relationships of various natural and synthetic telomerase inhibitors to help medicinal chemists and chemical biology researchers with a ready reference and updated status of their clinical trials. Suppression of human TERT (hTERT) activity through inhibition of hTERT promoter is an important approach for telomerase inhibition.
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Affiliation(s)
| | | | - G J Peters
- Department of Medical Oncology, VU University Medical Centre, Amsterdam, The Netherlands
| | - Y C Mayur
- SPPSPTM, SVKM's NMIMS, Mumbai, India
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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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12
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Qin L, Yan P, Xie C, Huang J, Ren Z, Li X, Best S, Cai X, Han G. Gold nanorod-assembled ZnGa 2O 4:Cr nanofibers for LED-amplified gene silencing in cancer cells. NANOSCALE 2018; 10:13432-13442. [PMID: 29972189 DOI: 10.1039/c8nr03802c] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Nanoparticles are now commonly used as non-viral gene vectors for RNA interference (RNAi) in cancer therapy but suffer from low targeting efficiency in situ. Meanwhile, localized drug delivery systems do not offer the effective capability for intracellular gene transportation. We describe here the design and synthesis of a localized therapeutic system, consisting of gold nanorods (Au NRs) loaded with hTERT siRNA assembled on the surface of ZnGa2O4:Cr (ZGOC) nanofibers. This composite system offers the potential for a LED-induced mild photothermal effect which enhances the phagocytosis of Au NRs carrying siRNA and the subsequent release of siRNA in the cytoplasm. Both phenomena amplify the gene silencing effect and consequently offer the potential for a superior therapeutic outcome.
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Affiliation(s)
- Lun Qin
- State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, P. R. China.
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13
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Houshmand M, Yazdi N, Kazemi A, Atashi A, Hamidieh AA, Anjam Najemdini A, Mohammadi Pour M, Nikougoftar Zarif M. Long non-coding RNA PVT1 as a novel candidate for targeted therapy in hematologic malignancies. Int J Biochem Cell Biol 2018; 98:54-64. [PMID: 29510227 DOI: 10.1016/j.biocel.2018.03.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2017] [Revised: 02/22/2018] [Accepted: 03/02/2018] [Indexed: 01/10/2023]
Abstract
Cancerous cells show resistance to various forms of therapy, so applying up to the minute targeted therapy is crucial. For this purpose, long non-coding RNA PVT1 as shown by recent studies is an important oncogene that interacts with vital cellular signaling pathways and different proteins such as c-Myc, NOP2 and LATS2. Due to the enormous role of long non-coding RNAs in development of leukemias, we aimed to show the role of PVT1 knock-down on fate of different hematologic cell lines. owing to this matter, various experiments such as Real-time PCR, cell cycle analysis and apoptosis assay were performed. Meanwhile, proliferation rate by CFSE, protein expression of c-Myc and hTERT by western blot and flow cytometry analysis were investigated. Our results demonstrated that PVT1 knock-down results in c-Myc degradation, proliferation down-regulation, induction of apoptosis and G0/G1 arrest. Simultaneously, for the first time, we posited the relation between this oncogene with hTERT that reduced after PVT1 knock-down. Considering these results, long non-coding RNA PVT1 may be a potential option for targeted therapy in hematologic malignancies.
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Affiliation(s)
- Mohammad Houshmand
- Blood Transfusion Research Center, High Institute for Research and Education in Transfusion Medicine, Tehran, Iran; Department of Clinical and Biological Sciences, University of Turin, San Luigi Gonzaga Hospital, Orbassano, Italy
| | - Narjes Yazdi
- Department of Molecular Genetics, Tehran Medical Branch, Islamic Azad University, Tehran, Iran
| | - Alireza Kazemi
- Department of Hematology and Blood Banking, School of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Amir Atashi
- Stem Cell and Tissue Engineering Research Center, Shahroud University of Medical Sciences, Shahroud, Iran
| | - Amir Ali Hamidieh
- Hematology, Oncology and Stem Cell Transplantation Research Centre, Tehran University of Medical Sciences, Tehran, Iran
| | - Ali Anjam Najemdini
- Department of Hematology and Blood Banking, School of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mahshid Mohammadi Pour
- Blood Transfusion Research Center, High Institute for Research and Education in Transfusion Medicine, Tehran, Iran
| | - Mahin Nikougoftar Zarif
- Blood Transfusion Research Center, High Institute for Research and Education in Transfusion Medicine, Tehran, Iran.
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14
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Berardinelli F, Coluzzi E, Sgura A, Antoccia A. Targeting telomerase and telomeres to enhance ionizing radiation effects in in vitro and in vivo cancer models. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2017; 773:204-219. [PMID: 28927529 DOI: 10.1016/j.mrrev.2017.02.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 02/13/2017] [Accepted: 02/14/2017] [Indexed: 01/05/2023]
Abstract
One of the hallmarks of cancer consists in the ability of tumor cells to divide indefinitely, and to maintain stable telomere lengths throughout the activation of specific telomere maintenance mechanisms (TMM). Therefore in the last fifteen years, researchers proposed to target telomerase or telomeric structure in order to block limitless replicative potential of cancer cells providing a fascinating strategy for a broad-spectrum cancer therapy. In the present review, we report in vitro and in vivo evidence regarding the use of chemical agents targeting both telomerase or telomere structure and showing promising antitumor effects when used in combination with ionizing radiation (IR). RNA interference, antisense oligonucleotides (e.g., GRN163L), non-nucleoside inhibitors (e.g., BIBR1532) and nucleoside analogs (e.g., AZT) represent some of the most potent strategies to inhibit telomerase activity used in combination with IR. Furthermore, radiosensitizing effects were demonstrated also for agents acting directly on the telomeric structure such as G4-ligands (e.g., RHPS4 and Telomestatin) or telomeric-oligos (T-oligos). To date, some of these compounds are under clinical evaluation (e.g., GRN163L and KML001). Advantages of Telomere/Telomerase Targeting Compounds (T/TTCs) coupled with radiotherapy may be relevant in the treatment of radioresistant tumors and in the development of new optimized treatment plans with reduced dose adsorbed by patients and consequent attenuation of short- end long-term side effects. Pros and cons of possible future applications in cancer therapy based on the combination of T/TCCs and radiation treatment are discussed.
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Affiliation(s)
- F Berardinelli
- Dipartimento di Scienze, Università Roma Tre, Rome Italy; Istituto Nazionale di Fisica Nucleare, INFN, Sezione di Roma Tre, Rome, Italy.
| | - E Coluzzi
- Dipartimento di Scienze, Università Roma Tre, Rome Italy
| | - A Sgura
- Dipartimento di Scienze, Università Roma Tre, Rome Italy; Istituto Nazionale di Fisica Nucleare, INFN, Sezione di Roma Tre, Rome, Italy
| | - A Antoccia
- Dipartimento di Scienze, Università Roma Tre, Rome Italy; Istituto Nazionale di Fisica Nucleare, INFN, Sezione di Roma Tre, Rome, Italy
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15
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Concomitant underexpression of TGFBR2 and overexpression of hTERT are associated with poor prognosis in cervical cancer. Sci Rep 2017; 7:41670. [PMID: 28195144 PMCID: PMC5307321 DOI: 10.1038/srep41670] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 12/28/2016] [Indexed: 12/26/2022] Open
Abstract
The human telomerase reverse transcriptase (hTERT) is highly expressed in a variety of tumors. The transforming growth factor beta receptor type II (TGFBR2) is a downstream protein of transforming growth factor beta (TGF-β) which suppresses telomerase activity. However, the relevance of survival to the expression of TGFBR2, hTERT or TGFBR2/hTERT has not been previously investigated in cervical cancer tissues. Our study showed that patients with low level of TGFBR2 were associated with poor prognosis (HR = 1.704, P = 0.021), but no significant relevance between hTERT expression and survival (HR = 1.390, P = 0.181). However, a combination of low level of TGFBR2 and high level of hTERT was associated with a worse survival (HR = 1.892, P = 0.020), which had higher impact of hazard ratio (HR) on the overall survival (OS) than the low TGFBR2 expression alone. Knockdown of TGFBR2 expression by shRNA in Hela cells increased cell proliferation, cell invasion, G1/S transition and telomere homeostasis but decreased cell apoptosis. Overexpressing TGFBR2 and inhibiting hTERT suppressed Hela cell growth. These results would lead us to further explore whether a phenotype of TGFBR2low/hTERThigh could be considered as a predictor of poor prognosis, and whether simultaneous use of TGFBR2 agonist and hTERT inhibitor could be developed as a therapeutic strategy.
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16
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Waghorn PA, Jackson MR, Gouverneur V, Vallis KA. Targeting telomerase with radiolabeled inhibitors. Eur J Med Chem 2017; 125:117-129. [PMID: 27657809 PMCID: PMC5154340 DOI: 10.1016/j.ejmech.2016.09.028] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Revised: 09/08/2016] [Accepted: 09/09/2016] [Indexed: 12/22/2022]
Abstract
The expression of telomerase in approximately 85% of cancers and its absence in the majority of normal cells makes it an attractive target for cancer therapy. However the lag period between initiation of telomerase inhibition and growth arrest makes direct inhibition alone an insufficient method of treatment. However, telomerase inhibition has been shown to enhance cancer cell radiosensitivity. To investigate the strategy of simultaneously inhibiting telomerase while delivering targeted radionuclide therapy to cancer cells, 123I-radiolabeled inhibitors of telomerase were synthesized and their effects on cancer cell survival studied. An 123I-labeled analogue of the telomerase inhibitor MST-312 inhibited telomerase with an IC50 of 1.58 μM (MST-312 IC50: 0.23 μM). Clonogenic assays showed a dose dependant effect of 123I-MST-312 on cell survival in a telomerase positive cell line, MDA-MB-435.
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Affiliation(s)
- Philip A Waghorn
- CR-UK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Off Roosevelt Drive, Oxford, OX3 7DQ, UK.
| | - Mark R Jackson
- CR-UK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Off Roosevelt Drive, Oxford, OX3 7DQ, UK.
| | - Veronique Gouverneur
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK.
| | - Katherine A Vallis
- CR-UK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Off Roosevelt Drive, Oxford, OX3 7DQ, UK.
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17
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Short-term inhibition of TERT induces telomere length-independent cell cycle arrest and apoptotic response in EBV-immortalized and transformed B cells. Cell Death Dis 2016; 7:e2562. [PMID: 28032863 PMCID: PMC5260987 DOI: 10.1038/cddis.2016.425] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 11/09/2016] [Accepted: 11/15/2016] [Indexed: 01/28/2023]
Abstract
Besides its canonical role in stabilizing telomeres, telomerase reverse transcriptase (TERT) may promote tumorigenesis through extra-telomeric functions. The possible therapeutic effects of BIBR1532 (BIBR), a powerful TERT inhibitor, have been evaluated in different cellular backgrounds, but no data are currently available regarding Epstein-Barr virus (EBV)-driven B-cell malignancies. Our aim was to characterize the biological effects of TERT inhibition by BIBR on EBV-immortalized lymphoblastoid cell lines (LCLs) and fully transformed Burkitt's lymphoma (BL) cell lines. We found that BIBR selectively inhibits telomerase activity in TERT-positive 4134/Late and 4134/TERT+ LCLs and EBV-negative BL41 and EBV-positive BL41/B95.8 BL cell lines. TERT inhibition led to decreased cell proliferation, accumulation of cells in the S-phase and ultimately to increased apoptosis, compared with mock-treated control cells. All these effects occurred within 72 h and were not observed in BIBR-treated TERT-negative 4134/TERT- and U2OS cells. The cell cycle arrest and apoptosis, consequent upon short-term TERT inhibition, were associated with and likely dependent on the activation of the DNA damage response (DDR), highlighted by the increased levels of γH2AX and activation of ATM and ATR pathways. Analyses of the mean and range of telomere lengths and telomere dysfunction-induced foci indicated that DDR after short-term TERT inhibition was not related to telomere dysfunction, thus suggesting that TERT, besides stabilizing telomere, may protect DNA via telomere-independent mechanisms. Notably, TERT-positive LCLs treated with BIBR in combination with fludarabine or cyclophosphamide showed a significant increase in the number of apoptotic cells with respect to those treated with chemotherapeutic agents alone. In conclusion, TERT inhibition impairs cell cycle progression and enhances the pro-apoptotic effects of chemotherapeutic agents in TERT-positive cells. These results support new therapeutic applications of TERT inhibitors in EBV-driven B-cell malignancies.
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18
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Ropio J, Merlio JP, Soares P, Chevret E. Telomerase Activation in Hematological Malignancies. Genes (Basel) 2016; 7:genes7090061. [PMID: 27618103 PMCID: PMC5039560 DOI: 10.3390/genes7090061] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 07/15/2016] [Accepted: 07/29/2016] [Indexed: 12/18/2022] Open
Abstract
Telomerase expression and telomere maintenance are critical for cell proliferation and survival, and they play important roles in development and cancer, including hematological malignancies. Transcriptional regulation of the rate-limiting subunit of human telomerase reverse transcriptase gen (hTERT) is a complex process, and unveiling the mechanisms behind its reactivation is an important step for the development of diagnostic and therapeutic applications. Here, we review the main mechanisms of telomerase activation and the associated hematologic malignancies.
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Affiliation(s)
- Joana Ropio
- Cutaneous Lymphoma Oncogenesis Team INSERM U1053 Bordeaux Research in Translational Oncology, Bordeaux University, Bordeaux 33076, France.
- Institute of Biomedical Sciences of Abel Salazar, University of Porto, Porto 4050-313, Portugal.
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto 4200-135, Portugal.
- Institute of Molecular Pathology and Immunology of the University of Porto (Ipatimup)-Cancer Biology, Rua Dr. Roberto Frias, s/n, Porto 4200-465, Portugal.
| | - Jean-Philippe Merlio
- Cutaneous Lymphoma Oncogenesis Team INSERM U1053 Bordeaux Research in Translational Oncology, Bordeaux University, Bordeaux 33076, France.
- Tumor Bank and Tumor Biology Laboratory, University Hospital Center Bordeaux, Pessac 33604, France.
| | - Paula Soares
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto 4200-135, Portugal.
- Institute of Molecular Pathology and Immunology of the University of Porto (Ipatimup)-Cancer Biology, Rua Dr. Roberto Frias, s/n, Porto 4200-465, Portugal.
- Department of Pathology and Oncology, Medical Faculty of Porto University, Porto 4200-319, Portugal.
| | - Edith Chevret
- Cutaneous Lymphoma Oncogenesis Team INSERM U1053 Bordeaux Research in Translational Oncology, Bordeaux University, Bordeaux 33076, France.
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Patties I, Kortmann RD, Menzel F, Glasow A. Enhanced inhibition of clonogenic survival of human medulloblastoma cells by multimodal treatment with ionizing irradiation, epigenetic modifiers, and differentiation-inducing drugs. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2016; 35:94. [PMID: 27317342 PMCID: PMC4912728 DOI: 10.1186/s13046-016-0376-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 06/13/2016] [Indexed: 12/17/2022]
Abstract
Background Medulloblastoma (MB) is the most common pediatric brain tumor. Current treatment regimes consisting of primary surgery followed by radio- and chemotherapy, achieve 5-year overall survival rates of only about 60 %. Therapy-induced endocrine and neurocognitive deficits are common late adverse effects. Thus, improved antitumor strategies are urgently needed. In this study, we combined irradiation (IR) together with epigenetic modifiers and differentiation inducers in a multimodal approach to enhance the efficiency of tumor therapy in MB and also assessed possible late adverse effects on neurogenesis. Methods In three human MB cell lines (DAOY, MEB-Med8a, D283-Med) short-time survival (trypan blue exclusion assay), apoptosis, autophagy, cell cycle distribution, formation of gH2AX foci, and long-term reproductive survival (clonogenic assay) were analyzed after treatment with 5-aza-2′-deoxycytidine (5-azadC), valproic acid (VPA), suberanilohydroxamic acid (SAHA), abacavir (ABC), all-trans retinoic acid (ATRA) and resveratrol (RES) alone or combined with 5-aza-dC and/or IR. Effects of combinatorial treatments on neurogenesis were evaluated in cultured murine hippocampal slices from transgenic nestin-CFPnuc C57BL/J6 mice. Life imaging of nestin-positive neural stem cells was conducted at distinct time points for up to 28 days after treatment start. Results All tested drugs showed a radiosynergistic action on overall clonogenic survival at least in two-outof-three MB cell lines. This effect was pronounced in multimodal treatments combining IR, 5-aza-dC and a second drug. Hereby, ABC and RES induced the strongest reduction of clongenic survival in all three MB cell lines and led to the induction of apoptosis (RES, ABC) and/or autophagy (ABC). Additionally, 5-aza-dC, RES, and ABC increased the S phase cell fraction and induced the formation of gH2AX foci at least in oneout-of-three cell lines. Thereby, the multimodal treatment with 5-aza-dC, IR, and RES or ABC did not change the number of normal neural progenitor cells in murine slice cultures. Conclusion In conclusion, the radiosensitizing capacities of epigenetic and differentiation-inducing drugs presented here suggest that their adjuvant administration might improve MB therapy. Thereby, the combination of 5-aza-dC/IR with ABC and RES seemed to be the most promising to enhance tumor control without affecting the normal neural precursor cells.
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Affiliation(s)
- Ina Patties
- Department of Radiation Therapy, University of Leipzig, Stephanstraße 9a, Leipzig, 04103, Germany.
| | - Rolf-Dieter Kortmann
- Department of Radiation Therapy, University of Leipzig, Stephanstraße 9a, Leipzig, 04103, Germany
| | - Franziska Menzel
- Institute of Anatomy, University of Leipzig, Liebigstraße 13, 04103, Leipzig, Germany
| | - Annegret Glasow
- Department of Radiation Therapy, University of Leipzig, Stephanstraße 9a, Leipzig, 04103, Germany
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20
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Zhang X, Li B, de Jonge N, Björkholm M, Xu D. The DNA methylation inhibitor induces telomere dysfunction and apoptosis of leukemia cells that is attenuated by telomerase over-expression. Oncotarget 2016; 6:4888-900. [PMID: 25682873 PMCID: PMC4467122 DOI: 10.18632/oncotarget.2917] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2014] [Accepted: 12/14/2014] [Indexed: 01/27/2023] Open
Abstract
DNA methyltransferase inhibitors (DNMTIs) such as 5-azacytidine (5-AZA) have been used for treatment of acute myeloid leukemia (AML) and other malignancies. Although inhibiting global/gene-specific DNA methylation is widely accepted as a key mechanism behind DNMTI anti-tumor activity, other mechanisms are likely involved in DNMTI's action. Because telomerase reverse transcriptase (TERT) plays key roles in cancer through telomere elongation and telomere lengthening-independent activities, and TERT has been shown to confer chemo- or radio-resistance to cancer cells, we determine whether DNMTIs affect telomere function and whether TERT/telomerase interferes with their anti-cancer efficacy. We showed that 5-AZA induced DNA damage and telomere dysfunction in AML cell lines by demonstrating the presence of 53-BP1 foci and the co-localization of 53-BP1 foci with telomere signals, respectively. Telomere dysfunction was coupled with diminished TERT expression, shorter telomere and apoptosis in 5-AZA-treated cells. However, 5-AZA treatment did not lead to changes in the methylation status of subtelomere regions. Down-regulation of TERT expression similarly occurred in primary leukemic cells derived from AML patients exposed to 5-AZA. TERT over-expression significantly attenuated 5-AZA-mediated DNA damage, telomere dysfunction and apoptosis of AML cells. Collectively, 5-AZA mediates the down-regulation of TERT expression, and induces telomere dysfunction, which consequently exerts an anti-tumor activity.
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Affiliation(s)
- Xiaolu Zhang
- Department of Medicine, Division of Hematology and Center for Molecular Medicine, Karolinska Institutet and Karolinska University Hospital Solna, Stockholm, Sweden
| | - Bingnan Li
- Department of Medicine, Division of Hematology and Center for Molecular Medicine, Karolinska Institutet and Karolinska University Hospital Solna, Stockholm, Sweden
| | - Nick de Jonge
- Department of Medicine, Division of Hematology and Center for Molecular Medicine, Karolinska Institutet and Karolinska University Hospital Solna, Stockholm, Sweden
| | - Magnus Björkholm
- Department of Medicine, Division of Hematology and Center for Molecular Medicine, Karolinska Institutet and Karolinska University Hospital Solna, Stockholm, Sweden
| | - Dawei Xu
- Department of Medicine, Division of Hematology and Center for Molecular Medicine, Karolinska Institutet and Karolinska University Hospital Solna, Stockholm, Sweden
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21
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Yang X, Li Z, Yang L, Lei H, Yu H, Liao Z, Zhou F, Xie C, Zhou Y. Knockdown of telomeric repeat binding factor 2 enhances tumor radiosensitivity regardless of telomerase status. J Cancer Res Clin Oncol 2015; 141:1545-52. [DOI: 10.1007/s00432-015-1911-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 01/05/2015] [Indexed: 10/24/2022]
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22
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Fan XK, Yan RH, Li BJ, Chen XM, Wei L, Wang Z. Antisense oligodeoxynucleotide against human telomerase reverse transcriptase inhibits the proliferation of Eca-109 esophageal carcinoma cells. Exp Ther Med 2014; 8:1247-1252. [PMID: 25187833 PMCID: PMC4151687 DOI: 10.3892/etm.2014.1897] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Accepted: 07/14/2014] [Indexed: 12/13/2022] Open
Abstract
Previous studies have demonstrated that the growth of tumor cells may be inhibited by antisense oligonucleotides (ASODNs) targeted against human telomerase (hTR) or human telomerase reverse transcriptase (hTERT), resulting in antitumor activity in a wide variety of tumors. However, few studies have investigated the effect of hTERT gene-targeted ASODNs on telomerase activity and cell proliferation in human esophageal cancer. In the present study, an MTT assay was used to determine the growth inhibition rate of Eca-109 cells treated with a hTERT-targeted phosphorothioate-ASODN (PS-ASODN). An inverted microscope was used to observe the morphologic changes of the cells following treatment with 5 μM PS-ASODN for 10 days. Telomerase activity was detected using the silver staining semi-quantitative telomeric repeat amplification protocol (TRAP) assay. Following treatment with the PS-ASODN (1–5 μmol/l), the proliferation of the Eca-109 cells was inhibited. The differences in inhibition rate between the PS-ASODN and blank control groups were statistically significant (P<0.05) when the concentration of the PS-ASODN was ≥2 μmol/l, whereas no statistically significant difference was identified between the non-specific-ASODN and blank control groups. The inhibition rate increased gradually as the concentration of the PS-ASODN increased and with time, suggesting that the PS-ASODN inhibited the growth of Eca-109 cells in a concentration-dependent, time-dependent and sequence-specific manner. The growth rate of the cells incubated with the PS-ASODN was reduced compared with that of the control cells. Cells treated with the PS-ASODN became round, suspended and reduced in size. The PS-ASODN was also found to inhibit telomerase activity. The ability of the PS-ASODN to inhibit the telomerase activity and cell proliferation of the Eca-109 cell line suggests that ASODNs have the potential to be novel therapeutic agents for the treatment of esophageal cancer.
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Affiliation(s)
- Xiang-Kui Fan
- Department of Thoracic Surgery, Shandong Provincial Hospital, Shandong University, Jinan, Shandong 250012, P.R. China ; Department of Tumour Surgery, Taian Central Hospital, Taian, Shandong 271000, P.R. China
| | - Rui-Hua Yan
- Coal Workers' Sanatorium of Tanshan, Taian, Shandong 271000, P.R. China
| | - Bao-Jiang Li
- Department of Tumour Surgery, Taian Central Hospital, Taian, Shandong 271000, P.R. China
| | - Xiang-Ming Chen
- Department of Tumour Surgery, Taian Central Hospital, Taian, Shandong 271000, P.R. China
| | - Lin Wei
- Department of Tumour Surgery, Taian Central Hospital, Taian, Shandong 271000, P.R. China
| | - Zhou Wang
- Department of Thoracic Surgery, Shandong Provincial Hospital, Shandong University, Jinan, Shandong 250012, P.R. China
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Laster BH, Isaacson C, Perets E, Msamra M, Priel E, Kalef-Ezra J, Kost J. Keeping those telomeres short! an innovative intratumoral long-term drug delivery system. J Cancer Res Clin Oncol 2014; 141:23-34. [DOI: 10.1007/s00432-014-1747-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Accepted: 06/10/2014] [Indexed: 11/24/2022]
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24
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Fekri Aval S, Akbarzadeh A, Yamchi MR, Zarghami F, Nejati-Koshki K, Zarghami N. Gene silencing effect of SiRNA-magnetic modified with biodegradable copolymer nanoparticles on hTERT gene expression in lung cancer cell line. ARTIFICIAL CELLS NANOMEDICINE AND BIOTECHNOLOGY 2014; 44:188-93. [DOI: 10.3109/21691401.2014.934456] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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25
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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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Shim G, Ricoul M, Hempel WM, Azzam EI, Sabatier L. Crosstalk between telomere maintenance and radiation effects: A key player in the process of radiation-induced carcinogenesis. MUTATION RESEARCH. REVIEWS IN MUTATION RESEARCH 2014; 760:S1383-5742(14)00002-7. [PMID: 24486376 PMCID: PMC4119099 DOI: 10.1016/j.mrrev.2014.01.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 01/14/2014] [Accepted: 01/22/2014] [Indexed: 02/06/2023]
Abstract
It is well established that ionizing radiation induces chromosomal damage, both following direct radiation exposure and via non-targeted (bystander) effects, activating DNA damage repair pathways, of which the proteins are closely linked to telomeric proteins and telomere maintenance. Long-term propagation of this radiation-induced chromosomal damage during cell proliferation results in chromosomal instability. Many studies have shown the link between radiation exposure and radiation-induced changes in oxidative stress and DNA damage repair in both targeted and non-targeted cells. However, the effect of these factors on telomeres, long established as guardians of the genome, still remains to be clarified. In this review, we will focus on what is known about how telomeres are affected by exposure to low- and high-LET ionizing radiation and during proliferation, and will discuss how telomeres may be a key player in the process of radiation-induced carcinogenesis.
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Nasiri M, Zarghami N, Koshki KN, Mollazadeh M, Moghaddam MP, Yamchi MR, Esfahlan RJ, Barkhordari A, Alibakhshi A. Curcumin and Silibinin Inhibit Telomerase Expression in T47D Human Breast Cancer Cells. Asian Pac J Cancer Prev 2013; 14:3449-3453. [DOI: 10.7314/apjcp.2013.14.6.3449] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/02/2023] Open
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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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Chang H, Rha SY, Jeung HC, Park KH, Kim TS, Kim YB, Chung HC. Telomerase- and angiogenesis-related gene responses to irradiation in human umbilical vein endothelial cells. Int J Mol Med 2013; 31:1202-8. [PMID: 23503666 DOI: 10.3892/ijmm.2013.1300] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Accepted: 03/05/2013] [Indexed: 11/06/2022] Open
Abstract
In this study, we investigated the effects of ionizing radiation (IR) on human umbilical vein endothelial cells (HUVECs) in the context of senescence. HUVECs at passage number (PN)1, PN2 and PN3 were exposed to irradiation (2 Gy). The growth rate of the HUVECS was measured by proliferation assay and senescence-associated β-galactosidase assay was used to measure the number of senescent cells. Telomerase activity and the expression of telomerase- and angiogenesis-related genes were measured by telomerase assay and real-time PCR, respectively. The number of senescent cells was significantly increased in the irradiated HUVECs at all PNs. Compared to the controls, telomerase activity, the expression of human telomerase reverse transcriptase (hTERT) and c-Myc in the irradiated HUVECs were downregulated during serial passage. The downregulation of vascular endothelial growth factor (VEGF) was observed in the irradiated HUVECs as the PN increased. The data presented in this study may aid in the understanding of the mechanisms behind IR‑induced EC senescence and telomerase- and angiogenesis‑related gene response.
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Affiliation(s)
- Hyun Chang
- Division of Medical Oncology, Department of Internal Medicine, Yonsei University College of Medicine, Seodaemun‑gu, Seoul 120-752, Republic of Korea
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Novel connections between DNA replication, telomere homeostasis, and the DNA damage response revealed by a genome-wide screen for TEL1/ATM interactions in Saccharomyces cerevisiae. Genetics 2013; 193:1117-33. [PMID: 23378069 DOI: 10.1534/genetics.113.149849] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Tel1 is the budding yeast ortholog of the mammalian tumor suppressor and DNA damage response (DDR) kinase ATM. However, tel1-Δ cells, unlike ATM-deficient cells, do not exhibit sensitivity to DNA-damaging agents, but do display shortened (but stably maintained) telomere lengths. Neither the extent to which Tel1p functions in the DDR nor the mechanism by which Tel1 contributes to telomere metabolism is well understood. To address the first question, we present the results from a comprehensive genome-wide screen for genetic interactions with tel1-Δ that cause sensitivity to methyl methanesulfonate (MMS) and/or ionizing radiation, along with follow-up characterizations of the 13 interactions yielded by this screen. Surprisingly, many of the tel1-Δ interactions that confer DNA damage sensitivity also exacerbate the short telomere phenotype, suggesting a connection between these two phenomena. Restoration of normal telomere length in the tel1-Δ xxx-Δ mutants results in only minor suppression of the DNA damage sensitivity, demonstrating that the sensitivity of these mutants must also involve mechanisms independent of telomere length. In support of a model for increased replication stress in the tel1-Δ xxx-Δ mutants, we show that depletion of dNTP pools through pretreatment with hydroxyurea renders tel1-Δ cells (but not wild type) MMS-sensitive, demonstrating that, under certain conditions, Tel1p does indeed play a critical role in the DDR.
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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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32
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Samy M, Gattolliat CH, Pendino F, Hillion J, Nguyen E, Bombard S, Douc-Rasy S, Bénard J, Ségal-Bendirdjian E. Loss of the malignant phenotype of human neuroblastoma cells by a catalytically inactive dominant-negative hTERT mutant. Mol Cancer Ther 2012; 11:2384-93. [PMID: 22933702 DOI: 10.1158/1535-7163.mct-12-0281] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Telomerase, a ribonucleoprotein complex mainly composed of the reverse transcriptase catalytic subunit (human telomerase reverse transcriptase, hTERT) and the RNA component (hTR), is a key enzyme of cancer progression. That aggressive stage 4-neuroblastoma expressed high levels of telomerase activity, whereas favorable tumors had no or little telomerase expression and activity, prompted us to investigate the role of this enzyme in this tumor model of altered proliferation, neuronal differentiation, and apoptosis. A human MYCN-amplified neuroblastoma cell line (IGR-N-91) was engineered to stably express either the normal hTERT protein (WT-hTERT) or a catalytically inactive dominant-negative mutant of this protein (DN-hTERT). We showed that DN-hTERT expression inhibited the endogenous hTERT in the malignant neuroblasts without telomere shortening nor loss of in vitro proliferative capacity. Importantly, DN-hTERT expression induced major changes in cell morphology of neuroblasts that switched them from a neuronal to a substrate adherent phenotype, which was more prone to apoptosis and lost their tumorigenic properties in nude mice. These biologic effects arose from modifications in the expression of genes involved in both apoptosis and neuroblastoma biology. Taken together these results highlighted the functional relevance of noncanonical functions of hTERT in the determination of neuroblast cell fate. Therefore, our results envision new therapeutic strategies for metastatic neuroblastoma therapeutic management.
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Affiliation(s)
- Mona Samy
- INSERM UMR-S 1007, Université Paris-Descartes, 45 rue des Saints-Pères, 75006 Paris, France
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Shin JS, Foot T, Hong A, Zhang M, Lum T, Solomon MJ, Soon Lee C. Telomerase expression as a predictive marker of radiotherapy response in rectal cancer: in vitro and in vivo study. Pathology 2012; 44:209-15. [DOI: 10.1097/pat.0b013e3283511cd5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Chu ESM, Yow CMN. Modulation of telomerase and signal transduction proteins by hexyl-ALA-photodynamic therapy (PDT) in human doxorubicin resistant cancer cell models. Photodiagnosis Photodyn Ther 2012; 9:243-55. [PMID: 22959804 DOI: 10.1016/j.pdpdt.2011.12.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Revised: 12/04/2011] [Accepted: 12/05/2011] [Indexed: 01/09/2023]
Abstract
AIMS This study employed a doxorubicin resistant (MES-SA-Dx5) human uterine sarcoma cell line and its counterpart (MES-SA), to elucidate the efficacy of aminolevulinic acid-hexylester (hexyl-ALA) mediated PDT at molecular and transcriptional levels. METHODS Hexyl-ALA generated protoporphyrin IX in both cells were determined by molecular probes using Confocal Laser Scanning Microscopy. The hexyl-ALA-PDT induced signal transduction proteins and mode of cell death were quantitated by CASE ELISA assays and DAPI staining. The modulation of hTERT mRNA expression and telomerase activity were investigated by TaqMan real-time PCR and ELISA respectively. Hexyl-ALA-PDT mediated cell migratory effect was determined by wound-healing assay. RESULTS The results demonstrated that mitochondria were the major target of hexyl-ALA. At LD(30), hexyl-ALA-PDT significantly provoked an up-regulation of phosphorylated p38MAPK and JNK proteins in both cells. Hexyl-ALA-PDT down-regulated hTERT (a catalytic subunit of telomerase) mRNA expression and showed a strong correlation with diminished telomerase activity in both cells (MES-SA: r(2) = 0.9932; MES-SA-Dx5: r(2) = 0.9775). The suppression of cell migratory effect in both cells was obtained after hexyl-ALA-PDT. Further, 50% and 30% of apoptotic cells were attained at LD(50), for wild-type and drug resistant cells respectively. Unlike the wild-type, a higher PDT dose was crucial to induce apoptosis in the drug resistant cells. CONCLUSIONS Our study provides the first evidence that p38MAPK and JNK kinases played a vital role in triggering hexyl-ALA-PDT-induced apoptosis, down-regulated hTERT mRNA expression and telomerase activity in both proposed cells. In vivo studies are worth examining for the benefit of clinical applications in drug resistant cancers and PDT development.
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Affiliation(s)
- Ellie S M Chu
- Medical Laboratory Science Section, Department of Health Technology & Informatics, The Hong Kong Polytechnic University, Hong Kong Special Administrative Region, Kowloon
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Drissi R, Wu J, Hu Y, Bockhold C, Dome JS. Telomere shortening alters the kinetics of the DNA damage response after ionizing radiation in human cells. Cancer Prev Res (Phila) 2011; 4:1973-81. [PMID: 21930799 DOI: 10.1158/1940-6207.capr-11-0069] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Studies of telomerase-deficient mice and human cell lines have showed that telomere shortening enhances sensitivity to ionizing radiation (IR). The molecular basis for this observation remains unclear. To better understand the connection between telomere shortening and radiation sensitivity, we evaluated components of the DNA damage response pathway in normal human fibroblasts with short and long telomeres. Late-passage cells with short telomeres showed enhanced sensitivity to IR compared with early-passage cells with longer telomeres. Compared with early-passage cells, late-passage cells had a higher baseline level of phosphorylated H2AX protein (γH2AX) before IR but diminished peak levels of H2AX phosphorylation after treatment with IR. Both the appearance and disappearance of γH2AX foci were delayed in late-passage cells, indicative of delayed DNA repair. In contrast to the situation with H2AX, ATM and p53 phosphorylation kinetics were similar in early- and late-passage cells, but phosphorylation of the chromatin-bound ATM targets SMC1 and NBS1 was delayed in late-passage cells. Because impaired phosphorylation associated with short telomeres was restricted to chromatin-bound ATM targets, chromatin structure was assessed. DNA from cells with short telomeres was more resistant to digestion with micrococcal nuclease, indicative of compacted chromatin. Moreover, cells with short telomeres showed histone acetylation and methylation profiles consistent with heterochromatin. Together our data suggest a model in which short telomeres induce chromatin structure changes that limit access of activated ATM to its downstream targets on the chromatin, thereby providing a potential explanation for the increased radiation sensitivity seen with telomere shortening.
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Affiliation(s)
- Rachid Drissi
- Division of Oncology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229, USA.
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Telomerase promotes efficient cell cycle kinetics and confers growth advantage to telomerase-negative transformed human cells. Oncogene 2011; 31:954-65. [PMID: 21743490 DOI: 10.1038/onc.2011.292] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Constitutive telomerase activity maintains telomere length and confers immortal phenotypes to human cancers. The prevalence of telomerase, rather than a homologous recombination-based mechanism, in telomere length maintenance suggests that telomerase also has auxiliary roles in tumorigenesis. Here, we investigate growth advantages provided by the telomerase enzyme in oncogene-transformed human cells that do not require telomerase activity for telomere length control. Our data suggest that in oncogene-transformed cells, telomerase activity accelerates cell growth kinetics in a cell cycle phase-specific manner and promotes anchorage-independent growth. Coculture experiments demonstrated that this growth advantage conferred by telomerase activity is not due to increased cellular cross-talk. Growth advantages provided by telomerase required all functional aspects of the enzyme. Dissociation-of-activity-in-telomerase mutants and other functionally defective versions of telomerase were unable to promote oncogene-transformed cell growth, suggesting that canonical telomerase activities may be involved. We conclude that telomerase provides advantages to oncogene-transformed human cells, thereby supporting the development of telomerase-based anticancer chemotherapies targeting these growth-promoting effects.
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Zhang B, Qian D, Ma HH, Jin R, Yang PX, Cai MY, Liu YH, Liao YJ, Deng HX, Mai SJ, Zhang H, Zeng YX, Lin MC, Kung HF, Xie D, Huang JJ. Anthracyclines disrupt telomere maintenance by telomerase through inducing PinX1 ubiquitination and degradation. Oncogene 2011; 31:1-12. [PMID: 21643006 DOI: 10.1038/onc.2011.214] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Telomere maintenance is essential for cancer growth. Induction of telomere dysfunction, for example, by inhibition of telomeric proteins or telomerase, has been shown to strongly enhance cancer cells' sensitivity to chemotherapies. However, it is not clear whether modulations of telomere maintenance constitute cancer cellular responses to chemotherapies. Furthermore, the manner in which anti-cancer drugs affect telomere function remains unknown. In this study, we show that anthracyclines, a class of anti-cancer drugs widely used in clinical cancer treatments, have an active role in triggering telomere dysfunction specifically in telomerase-positive cancer cells. Anthracyclines interrupt telomere maintenance by telomerase through the downregulation of PinX1, a protein factor responsible for targeting telomerase onto telomeres, thereby inhibiting telomerase association with telomeres. We further demonstrate that anthracyclines downregulate PinX1 by inducing this protein degradation through the ubiquitin-proteasome-dependent pathway. Our data not only reveal a novel action for anthracyclines as telomerase functional inhibitors but also provide a clue for the development of novel anti-cancer drugs based on telomerase/telomere targeting, which is actively investigated by many current studies.
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Affiliation(s)
- B Zhang
- State Key Laboratory of Oncology in South China, Cancer Center, Sun Yat-Sen University, Guangzhou, China
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Park JE, Woo SR, Kang CM, Juhn KM, Ju YJ, Shin HJ, Joo HY, Park ER, Park IC, Hong SH, Hwang SG, Lee JK, Kim HK, Cho MH, Park GH, Lee KH. Paclitaxel stimulates chromosomal fusion and instability in cells with dysfunctional telomeres: implication in multinucleation and chemosensitization. Biochem Biophys Res Commun 2010; 404:615-21. [PMID: 21144828 DOI: 10.1016/j.bbrc.2010.12.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Accepted: 12/02/2010] [Indexed: 01/16/2023]
Abstract
The anticancer effect of paclitaxel is attributable principally to irreversible promotion of microtubule stabilization and is hampered upon development of chemoresistance by tumor cells. Telomere shortening, and eventual telomere erosion, evoke chromosomal instability, resulting in particular cellular responses. Using telomerase-deficient cells derived from mTREC-/-p53-/- mice, here we show that, upon telomere erosion, paclitaxel propagates chromosomal instability by stimulating chromosomal end-to-end fusions and delaying the development of multinucleation. The end-to-end fusions involve both the p- and q-arms in cells in which telomeres are dysfunctional. Paclitaxel-induced chromosomal fusions were accompanied by prolonged G2/M cell cycle arrest, delayed multinucleation, and apoptosis. Telomere dysfunctional cells with mutlinucleation eventually underwent apoptosis. Thus, as telomere erosion proceeds, paclitaxel stimulates chromosomal fusion and instability, and both apoptosis and chemosensitization eventually develop.
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Affiliation(s)
- Jeong-Eun Park
- Division of Radiation Cancer Research, Korea Institute of Radiological & Medical Sciences, Seoul 139-706, South Korea
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Tamakawa RA, Fleisig HB, Wong JMY. Telomerase inhibition potentiates the effects of genotoxic agents in breast and colorectal cancer cells in a cell cycle-specific manner. Cancer Res 2010; 70:8684-94. [PMID: 20837664 DOI: 10.1158/0008-5472.can-10-2227] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Previous studies have shown that telomerase facilitates DNA-damage repair and cell survival following stress. It is not clear how telomerase promotes DNA repair, or whether short-term telomerase inhibition, combined with genotoxic stress, can be exploited for cancer therapy. Here, we show that transient inhibition of telomerase activity by the specific inhibitor, GRN163L, increases the cytotoxicity of some, but not all, DNA-damaging agents. Such synergistic inhibition of growth requires the use of DNA-damaging agents that are toxic in the S/G(2) phase of the cell cycle. Notably, inhibition of Ataxia Telangiectasia Mutated (ATM) kinase, together with telomerase inhibition, synergistically increases the cytotoxicity induced by the G(2)-specific topoisomerase II inhibitor etoposide. By varying the timing of telomerase inhibition, relative to the timing of DNA damage, it is apparent that the prosurvival functions of telomerase occur at early stages of DNA damage recognition and repair. Our results suggest that the protective role of telomerase in cell cycle-restricted DNA damage repair could be exploited for combined anticancer chemotherapy.
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Affiliation(s)
- Raina A Tamakawa
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada
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Nakamura M, Kyo S, Zhang B, Zhang X, Mizumoto Y, Takakura M, Maida Y, Mori N, Hashimoto M, Ohno S, Inoue M. Prognostic impact of CD133 expression as a tumor-initiating cell marker in endometrial cancer. Hum Pathol 2010; 41:1516-29. [PMID: 20800872 DOI: 10.1016/j.humpath.2010.05.006] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2010] [Revised: 05/13/2010] [Accepted: 05/14/2010] [Indexed: 12/18/2022]
Abstract
Tumor-initiating cells are known to be the major source of tumor propagation and might be an attractive therapeutic target. The present study dissected the roles of CD133 as a tumor-initiating cell marker in endometrial cancer and investigated the prognostic impact of this marker expression. Flow cytometry using 6 endometrial cancer cell lines revealed that the frequency of CD133(+) cells varied widely among the cell types and that Ishikawa and MFE280 cells contained significantly higher ratio (10%-20%) of such cells; therefore, these were subjected to the subsequent analyses. Sorted CD133(+) cells showed more aggressive proliferative potential in vitro and more increased tumorigenicity in nude or NOD/SCID mice than CD133(-) cells and generated both CD133(+) and CD133(-) cells. Furthermore, they showed apparent resistance to cisplatin- or paclitaxel-induced cytotoxicity compared with CD133(-) cells. CD133(+) cells had a greater S-phase fraction than CD133(-) cells, and the serum starvation that induced G0/G1 accumulation decreased the population of CD133(+) cells. Finally, we immunohistochemically analyzed the CD133 expression in endometrial cancer specimens from 62 patients. CD133 expression was not significantly associated with any of the clinicopathologic characteristic of tumors. However, the Kaplan-Meier analysis revealed that tumors with high CD133 expression showed worse overall survival (P = .023, log-rank test) than those with low CD133 expression; and the Cox regression hazard model found that high CD133 expression was an independent prognostic factor (P = .045). Thus, the present study demonstrates that CD133 is not only a tumor-initiating cell marker but also a critical prognostic marker in endometrial cancer.
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Affiliation(s)
- Mitsuhiro Nakamura
- Department of Obstetrics and Gynecology, Kanazawa University Graduate School of Medical Science, Kanazawa, Ishikawa 920-8641, Japan
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Lee CC, Lin CP, Lee YL, Wang GC, Cheng YC, Liu HE. Meisoindigo is a promising agent with in vitro and in vivo activity against human acute myeloid leukemia. Leuk Lymphoma 2010; 51:897-905. [PMID: 20233051 DOI: 10.3109/10428191003672115] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Meisoindigo, a derivative of Indigo naturalis, has been used in China for chronic myeloid leukemia. In vitro cell line studies have shown that this agent might induce apoptosis and myeloid differentiation of acute myeloid leukemia (AML). In this study, we explored its mechanisms and potential in AML. NB4, HL-60, and U937 cells and primary AML cells were used to examine its effects and the NOD/SCID animal model was used to evaluate its in vivo activity. Meisoindigo inhibited the growth of leukemic cells by inducing marked apoptosis and moderate cell-cycle arrest at the G(0)/G(1) phase. It down-regulated anti-apoptotic Bcl-2, and up-regulated pro-apoptotic Bak and Bax and cell-cycle related proteins, p21and p27. Furthermore, it induced myeloid differentiation, as demonstrated by morphologic changes, up-regulation of CD11b, and increased nitroblue tetrazolium reduction activity in all cell lines tested. In addition, meisoindigo down-regulated the expression of human telomerase reverse transcriptase and enhanced the cytotoxicity of conventional chemotherapeutic agents, cytarabine and idarubicin. As with the results from cell lines, meisoindigo also induced apoptosis, up-regulated p21 and p27, and down-regulated Bcl-2 in primary AML cells. The in vivo anti-leukemic activity of meisoindigo was also demonstrated by decreased spleen size in a dose-dependent manner. Taking these results together, meisoindigo is a potential agent for AML.
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Affiliation(s)
- Chin-Cheng Lee
- Department of Pathology, Shin Kong Wu Ho Su Hospital, Taipei, Taiwan
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Kovalenko OA, Kaplunov J, Herbig U, deToledo S, Azzam EI, Santos JH. Expression of (NES-)hTERT in cancer cells delays cell cycle progression and increases sensitivity to genotoxic stress. PLoS One 2010; 5:e10812. [PMID: 20520826 PMCID: PMC2876026 DOI: 10.1371/journal.pone.0010812] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2010] [Accepted: 05/03/2010] [Indexed: 01/26/2023] Open
Abstract
Telomerase is a reverse transcriptase associated with cellular immortality through telomere maintenance. This enzyme is activated in 90% of human cancers, and inhibitors of telomerase are currently in clinical trials to counteract tumor growth. Many aspects of telomerase biology have been investigated for therapy, particularly inhibition of the enzyme, but little was done regarding its subcellular shuttling. We have recently shown that mutations in the nuclear export signal of hTERT, the catalytic component of telomerase, led to a mutant ((NES-)hTERT) that failed to immortalize cells despite nuclear localization and catalytic activity. Expression of (NES-)hTERT in primary fibroblast resulted in telomere-based premature senescence and mitochondrial dysfunction. Here we show that expression of (NES-)hTERT in LNCaP, SQ20B and HeLa cells rapidly and significantly decreases their proliferation rate and ability to form colonies in soft agar while not interfering with endogenous telomerase activity. The cancer cells showed increased DNA damage at telomeric and extra-telomeric sites, and became sensitive to ionizing radiation and hydrogen peroxide exposures. Our data show that expression of (NES-)hTERT efficiently counteracts cancer cell growth in vitro in at least two different ways, and suggest manipulation with the NES of hTERT or its subcellular shuttling as a new strategy for cancer treatment.
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Affiliation(s)
- Olga A. Kovalenko
- Department of Pharmacology and Physiology, New Jersey Medical School, Newark, New Jersey, United States of America
- Department of Pathology, New Jersey Medical School, Newark, New Jersey, United States of America
| | - Jessica Kaplunov
- Department of Microbiology and Molecular Genetics, New Jersey Medical School, Newark, New Jersey, United States of America
| | - Utz Herbig
- Department of Microbiology and Molecular Genetics, New Jersey Medical School, Newark, New Jersey, United States of America
| | - Sonia deToledo
- Department of Radiology, New Jersey Medical School, Newark, New Jersey, United States of America
| | - Edouard I. Azzam
- Department of Radiology, New Jersey Medical School, Newark, New Jersey, United States of America
| | - Janine H. Santos
- Department of Pharmacology and Physiology, New Jersey Medical School, Newark, New Jersey, United States of America
- * E-mail:
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Li Y, Malaeb BS, Li ZZ, Thompson MG, Chen Z, Corey DR, Hsieh JT, Shay JW, Koeneman KS. Telomerase enzyme inhibition (TEI) and cytolytic therapy in the management of androgen independent osseous metastatic prostate cancer. Prostate 2010; 70:616-29. [PMID: 20043297 PMCID: PMC3910097 DOI: 10.1002/pros.21096] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND Recurrent prostate cancer can be osseous, androgen independent and lethal. The purpose is to discern the efficacy of synthetic small molecule telomerase enzyme inhibitors (TEI) alone or in combination with other cytotoxic therapies in controlling metastatic osseous prostate cancer. METHODS C4-2B was pre-treated with a match or mismatch TEI for 6 weeks and then inoculated into nude mice subcutaneously or intraosseously. In a separate experiment, untreated C4-2B was injected into femur of nude mice. The mice were divided into seven systemic "combination" treatment groups of control, Ad-BSP-E1a virus, docetaxel, mismatch and match TEI. Serum PSA was followed longitudinally. Histology analyses and histomorphometry were performed. Repeated measure analysis was applied for statistical analysis and Bonferroni method was used in multiple comparisons. RESULTS In the pre-treated study, the PSA of match treated cells in subcutaneous or intraosseous model was significantly lower than mismatch TEI or PBS treated group (P < 0.05). Histology revealed increased fibrosis, apoptosis and decreased PSA staining in the match TEI treated subcutaneous xenografts. In the combination treatment study, the PSA was significantly lower in single/double treatment and triple treatment than control (P < 0.05). Histology revealed that triple therapy mice had normal femur architecture. Histomorphometrics revealed that the area of femur tumor and woven bone was significantly positively correlated (P = 0.007). CONCLUSIONS Multiple lines of data point toward the efficacy of systemically administered telomerase inhibitors. Combining cytotoxic regimens with telomerase inhibitors could be beneficial in controlling prostate cancer. Clinical trials are warranted to explore the efficacy of TEI in prostate cancer.
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Affiliation(s)
- Yingming Li
- Department of Urologic Surgery, Center for Prostate Cancer, University of Minnesota, Minneapolis, Minnesota
| | - Bahaa S. Malaeb
- Department of Urologic Surgery, Center for Prostate Cancer, University of Minnesota, Minneapolis, Minnesota
| | - Zhong-ze Li
- Biostatistics Core, Cancer Center, University of Minnesota, Minneapolis, Minnesota
| | - Melissa G. Thompson
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Zhi Chen
- Department of Pharmacology and Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas
| | - David R. Corey
- Department of Pharmacology and Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Jer-Tsong Hsieh
- Department of Urology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Jerry W. Shay
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Kenneth S. Koeneman
- Department of Urologic Surgery, Center for Prostate Cancer, University of Minnesota, Minneapolis, Minnesota
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Li W, Tao KX. Advances in research of the epigenetic regulation of hTERT expression. Shijie Huaren Xiaohua Zazhi 2010; 18:1026-1031. [DOI: 10.11569/wcjd.v18.i10.1026] [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
Human telomerase reverse transcriptase (hTERT), the catalytic subunit of the telomerase, is the rate-limiting component for telomerase activity. Epigenetic regulation of gene transcription does not change DNA sequences but depends on chemical modification of either DNA or histones or non-coding RNAs. Epigenetic regulation is inheritable and plays an important role in controlling gene expression. The expression of hTERT may also be subjected to epigenetic regulation, such as DNA methylation, histone acetylation and methylation, and non-coding RNAs.
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Uziel O, Beery E, Dronichev V, Samocha K, Gryaznov S, Weiss L, Slavin S, Kushnir M, Nordenberg Y, Rabinowitz C, Rinkevich B, Zehavi T, Lahav M. Telomere shortening sensitizes cancer cells to selected cytotoxic agents: in vitro and in vivo studies and putative mechanisms. PLoS One 2010; 5:e9132. [PMID: 20161752 PMCID: PMC2817744 DOI: 10.1371/journal.pone.0009132] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2009] [Accepted: 12/06/2009] [Indexed: 12/17/2022] Open
Abstract
Background Telomere/telomerase system has been recently recognized as an attractive target for anticancer therapy. Telomerase inhibition results in tumor regression and increased sensitivity to various cytotoxic drugs. However, it has not been fully established yet whether the mediator of these effects is telomerase inhibition per se or telomere shortening resulting from inhibition of telomerase activity. In addition, the characteristics and mechanisms of sensitization to cytotoxic drugs caused by telomerase inhibition has not been elucidated in a systematic manner. Methodology/Principal Findings In this study we characterized the relative importance of telomerase inhibition versus telomere shortening in cancer cells. Sensitization of cancer cells to cytotoxic drugs was achieved by telomere shortening in a length dependent manner and not by telomerase inhibition per se. In our system this sensitization was related to the mechanism of action of the cytotoxic drug. In addition, telomere shortening affected also other cancer cell functions such as migration. Telomere shortening induced DNA damage whose repair was impaired after administration of cisplatinum while doxorubicin or vincristine did not affect the DNA repair. These findings were verified also in in vivo mouse model. The putative explanation underlying the phenotype induced by telomere shortening may be related to changes in expression of various microRNAs triggered by telomere shortening. Conclusions/Significance To our best knowledge this is the first study characterizing the relative impact of telomerase inhibition and telomere shortening on several aspects of cancer cell phenotype, especially related to sensitivity to cytotoxic drugs and its putative mechanisms. The microRNA changes in cancer cells upon telomere shortening are novel information. These findings may facilitate the development of telomere based approaches in treatment of cancer.
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Affiliation(s)
- Orit Uziel
- Beilinson Hospital, Rabin Medical Center, Felsenstein Medical Research Center, Petah-Tikva, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Einat Beery
- Beilinson Hospital, Rabin Medical Center, Felsenstein Medical Research Center, Petah-Tikva, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Vladimir Dronichev
- Beilinson Hospital, Rabin Medical Center, Felsenstein Medical Research Center, Petah-Tikva, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Katty Samocha
- Beilinson Hospital, Rabin Medical Center, Felsenstein Medical Research Center, Petah-Tikva, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Sergei Gryaznov
- Geron Corporation, Menlo Park, California, United States of America
| | - Lola Weiss
- Department of Bone Marrow Transplantation and Cancer Immunotherapy, Hadassah University Hospital, Jerusalem, Israel
| | - Shimon Slavin
- Department of Bone Marrow Transplantation and Cancer Immunotherapy, Hadassah University Hospital, Jerusalem, Israel
| | | | - Yardena Nordenberg
- Beilinson Hospital, Rabin Medical Center, Felsenstein Medical Research Center, Petah-Tikva, Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | | | | | - Tania Zehavi
- Department of Pathology, Meir Medical Center, Kfar-Saba, Israel
| | - Meir Lahav
- Beilinson Hospital, Rabin Medical Center, Felsenstein Medical Research Center, Petah-Tikva, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
- * E-mail:
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Palumbo SL, Ebbinghaus SW, Hurley LH. Formation of a unique end-to-end stacked pair of G-quadruplexes in the hTERT core promoter with implications for inhibition of telomerase by G-quadruplex-interactive ligands. J Am Chem Soc 2009; 131:10878-91. [PMID: 19601575 DOI: 10.1021/ja902281d] [Citation(s) in RCA: 201] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The hTERT core promoter contains a G-rich region of 12 consecutive G-tracts, embracing 3 Sp1 binding sites, and has the potential to form multiple G-quadruplexes. From the 12 runs of guanines, 9 putative hTERT G-quadruplex-forming sequences were selected to assay for G-quadruplex formation and stability using circular dichroism and a Taq polymerase stop assay. Results from biophysical and chemical assays demonstrate an approximate inverse correlation between total loop size and structure stability. Investigation of the full-length hTERT G-rich sequence using a Taq polymerase stop assay and dimethyl sulfate footprinting revealed the formation of a unique end-to-end stacked G-quadruplex structure from this sequence. This structure consists of an all parallel G-quadruplex, formed by four consecutive G-tracts, linked to another, atypical G-quadruplex, formed by two pairs of consecutive G-tracts separated by a 26-base loop. This 26-base loop likely forms a stable hairpin structure, which would explain the unexpected stability of this G-quadruplex. Significantly, the formation of this tandem G-quadruplex structure in the full-length sequence masks all three Sp1 binding sites, which is predicted to produce significant inhibition of hTERT promoter activity. Furthermore, our study implies that inhibition of telomerase activity by some G-quadruplex ligands is not only produced by targeting telomeric G-quadruplexes but also by stabilization of the hTERT promoter G-quadruplexes.
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Affiliation(s)
- SunMi L Palumbo
- Arizona Cancer Center, University of Arizona, 1515 North Campbell Avenue, Tucson, Arizona 85724, USA
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Keller G, Brassat U, Braig M, Heim D, Wege H, Brümmendorf TH. Telomeres and telomerase in chronic myeloid leukaemia: impact for pathogenesis, disease progression and targeted therapy. Hematol Oncol 2009; 27:123-9. [PMID: 19569255 DOI: 10.1002/hon.901] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Telomeres are specialized structures localized at the end of human chromosomes. Due to the end replication problem, each cell division results in a loss of telomeric repeats in normal somatic cells. In germ line and stem cells, the multicomponent enzyme telomerase maintains the length of telomere repeats. However, elevated telomerase activity has also been reported in the majority of solid tumours as well as in acute and chronic leukaemia. Chronic myeloid leukaemia (CML) serves as a model disease to study telomere biology in clonal myeloproliferative disorders. In CML, telomere shortening correlates with disease stage, duration of chronic phase (CP), prognosis measured by the Hasford risk score and the response to disease-modifying therapeutics such as the tyrosine kinase inhibitor Imatinib. In addition, telomerase activity (TA) is already increased in CP CML and further upregulated with disease progression to accelerated phase and blast crisis (BC). Furthermore, a correlation of TA with increased genetic instability as well as a shorter survival of the patients has been reported. Here, we review the current state of knowledge of the role of telomere and telomerase biology in CML and discuss the possible impact of novel treatment approaches.
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Affiliation(s)
- Gunhild Keller
- Klinik für Onkologie und Hämatologie mit der Sektion Pneumologie, Universitäres Cancer Center Hamburg (UCCH), Universitätsklinikum Hamburg-Eppendorf, 20246 Hamburg, Germany
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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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Poynter KR, Sachs PC, Bright AT, Breed MS, Nguyen BN, Elmore LW, Holt SE. Genetic inhibition of telomerase results in sensitization and recovery of breast tumor cells. Mol Cancer Ther 2009; 8:1319-27. [PMID: 19417141 DOI: 10.1158/1535-7163.mct-08-0849] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Telomerase, a ribonucleoprotein enzyme minimally composed of an RNA template (human telomerase RNA) and a catalytically active protein subunit (human telomerase reverse transcriptase), synthesizes telomeric repeats onto chromosome ends and is obligatory for continuous tumor cell proliferation. Telomerase is an attractive anticancer therapeutic target because its activity is present in >90% of human cancers, including >95% of breast carcinomas. Traditional chemotherapies lack the ability to effectively control and cure breast cancer, in part because residual cells are often resistant to DNA-damaging modalities. Although numerous telomerase inhibition strategies cause cancer cells to undergo apoptosis or senescence, there is often a lag period between the beginning of the treatment regimen and a biological effect. Thus, our goal for these studies was to show that effectively blocking telomerase genetically together with standard chemotherapeutic agents, doxorubicin/Adriamycin or Taxol, would increase the sensitization and efficacy for triggering senescence and/or apoptosis in cultures of breast cancer cells while reducing toxicity. We find that blocking telomerase in breast tumor cells substantially increases the sensitization at lower doses of Adriamycin or Taxol and that the kinetics of senescence/apoptosis is more rapid at higher concentrations. Combined with telomerase inhibition, Taxol treatment induced both apoptosis (its typical cell fate) and senescence, both at high enough levels to suggest that these two cellular responses are not mutually exclusive. Genetic inhibition of telomerase is eventually reversed due to up-regulation of endogenous telomerase activity without a net change in telomere length, suggesting that telomerase inhibition itself, not necessarily short telomeres, is important for sensitization.
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Affiliation(s)
- Kennon R Poynter
- Department of Human Genetics, Medical College of Virginia at Virginia Commonwealth University, Richmond, Virginia 23298-0662, USA
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