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Atroosh F, Al-Habori M, Al-Eryani E, Saif-Ali R. Impact of khat (Catha edulis) and oral contraceptive use on telomerase levels and tumor suppressor genes p53 and p21 in normal subjects and breast cancer patients. Sci Rep 2024; 14:16365. [PMID: 39013992 PMCID: PMC11252306 DOI: 10.1038/s41598-024-67355-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2024] [Accepted: 07/10/2024] [Indexed: 07/18/2024] Open
Abstract
This study aimed to evaluate the effects of oral contraceptive (OC) use, khat chewing, and their combined effect on telomerase level and tumor suppressor genes, p53 and p21 in breast cancer (BC) patients and normal volunteers. 140 Yemeni women aged 25-40 years old enrolled, 60 newly diagnosed pretreated BC patients, and 80 control subjects. Venous blood (5 ml) was collected and the results showed BC patients to have significantly raised levels of telomerase, p53, and p21 compared to the control group. The use of OCs significantly raised telomerase in control group with no effect in BC patients; whereas p53 and p21 were significantly increased in BC patients. On the other hand, khat chewing significantly increased p53 in controls and BC patients, whereas p21 was significantly raised in BC patients. The combined use of OCs and khat chewing significantly increased telomerase and p53 in control group, and significantly increased p53 and p21 in BC patients. Telomerase was shown to be a risk factor (OR 4.4) for BC, and the use of OCs was a high-risk factor for increasing telomerase (OR 27.8) in normal subjects. In contrast, khat chewing was shown to be protective (OR 0.142), and the combined use of OCs and khat chewing decreased the risk factor of telomerase from OR 27.8 to 2.1.
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Affiliation(s)
- Fairooz Atroosh
- Department of Biochemistry and Molecular Biology, Faculty of Medicine and Health Sciences, Sana'a University, Sana'a, Republic of Yemen
| | - Molham Al-Habori
- Department of Biochemistry and Molecular Biology, Faculty of Medicine and Health Sciences, Sana'a University, Sana'a, Republic of Yemen.
| | - Ekram Al-Eryani
- Department of Biochemistry and Molecular Biology, Faculty of Medicine and Health Sciences, Sana'a University, Sana'a, Republic of Yemen
| | - Riyadh Saif-Ali
- Department of Biochemistry and Molecular Biology, Faculty of Medicine and Health Sciences, Sana'a University, Sana'a, Republic of Yemen
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2
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Engin AB, Engin A. The effect of environmental Bisphenol A exposure on breast cancer associated with obesity. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2021; 81:103544. [PMID: 33161112 DOI: 10.1016/j.etap.2020.103544] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 10/30/2020] [Accepted: 11/01/2020] [Indexed: 06/11/2023]
Abstract
Bisphenol A (BPA) is a widely used endocrine disrupter. Its environmental exposure is a causative factor of cell aging via decreasing telomerase activity, thus leading to shortening of telomere length. Epidemiological studies confirm positive associations between BPA exposure and the incidence of obesity and type 2 diabetes (T2DM). Increased urinary BPA levels in obese females are both significantly correlated with shorter relative telomere length and T2DM. BPA is a critically effective endocrine disrupter leading to poor prognosis via the obesity-inflammation-aromatase axis in breast cancer. Environmental BPA exposure contributes to the progression of both estrogen dependent and triple negative breast cancers. BPA is a positive regulator of human telomerase reverse transcriptase (hTERT) and it increases the expression of hTERT mRNA in breast cancer cells. BPA exposure can lead to tamoxifen resistance. Among patients treated with chemotherapy, those with persistent high telomerase activity due to BPA are at higher risk of death.
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Affiliation(s)
- Ayse Basak Engin
- Gazi University, Faculty of Pharmacy, Department of Toxicology, Ankara, Turkey.
| | - Atilla Engin
- Gazi University, Faculty of Medicine, Department of General Surgery, Ankara, Turkey
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3
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Shah NG, Choksi TJ, Patel DD, Vora HH, Ghosh N, Trivedi TI, Trivedi KA. Telomerase Activity in Breast Cancer in Western India (Gujarat). Int J Biol Markers 2018; 17:49-55. [PMID: 11936586 DOI: 10.1177/172460080201700106] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The purpose of this study was to examine the association of telomerase activity with clinical and histopathological prognostic variables in primary breast cancer (n=64). Telomerase activity in breast cancer was also compared with that in benign (n=10) and non-malignant tissues (n=8; post-lumpectomy tissues histopathologically defined as containing no residual tumor). The parameter was assessed using the Telomerase PCR ELISA kit. Values above OD 0.120 were considered positive. Estrogen and progesterone receptors (ER and PgR) were assayed by the dextran-coated charcoal method and levels >10 fmol/mg cytosol protein were taken as positive. Telomerase activity was detected in 20% and 50% of the patients with benign lesions and primary breast cancer, respectively, and in 50% of post-lumpectomy breast tissues histopathologically defined as containing no residual tumor. Telomerase activity was present in all stages of breast carcinoma and showed a significant inverse correlation with lymph node status (p=0.006), lymphatic invasion (p=0.035) and necrosis (p=0.033). Moreover, when stage II patients were grouped according to nodal involvement, a trend towards significance was observed (p=0.055). No correlation was observed with ER and PgR. The results of our study suggest that telomerase activity might be associated with the presence of cancer cells. Furthermore, telomerase activation may occur early in breast cancer and may be periodically downregulated during subsequent tumor progression.
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Affiliation(s)
- N G Shah
- Division of Molecular Endocrinology, Department of Cancer Biology, Gujarat Cancer and Research Institute, Ahmedabad, India.
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4
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Dinami R, Buemi V, Sestito R, Zappone A, Ciani Y, Mano M, Petti E, Sacconi A, Blandino G, Giacca M, Piazza S, Benetti R, Schoeftner S. Epigenetic silencing of miR-296 and miR-512 ensures hTERT dependent apoptosis protection and telomere maintenance in basal-type breast cancer cells. Oncotarget 2017; 8:95674-95691. [PMID: 29221158 PMCID: PMC5707052 DOI: 10.18632/oncotarget.21180] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 08/27/2017] [Indexed: 12/31/2022] Open
Abstract
The catalytic subunit of the telomerase complex, hTERT, ensures unlimited proliferative potential of cancer cells by maintaining telomere function and protecting from apoptosis. Using a miRNA screening approach we identified miR-296-5p and miR-512-5p as miRNAs that target hTERT in breast cancer cells. Ectopic miR-296-5p and miR-512-5p reduce telomerase activity, drive telomere shortening and cause proliferation defects by enhancing senescence and apoptosis in breast cancer cells. In line with the relevance of hTERT expression for human cancer we found that miR-296-5p and miR-512-5p expression is reduced in human breast cancer. Accordingly, high expression of miR-296-5p and miR-512-5p target genes including hTERT is linked with significantly reduced distant metastasis free survival and relapse free survival of basal type breast cancer patients. This suggests relevance of the identified miRNAs in basal type breast cancer. Epigenetic silencing of miR-296 and miR-512 encoding genes is responsible for low levels of miR-296-5p and miR-512-5p expression in basal type breast cancer cells. Disrupting gene silencing results in a dramatic upregulation of miR-296-5p and miR-512-5p levels leading to reduced hTERT expression and increased sensitivity to the induction of apoptosis. Altogether, our data suggest that epigenetic regulatory circuits in basal type breast cancer may contribute to high hTERT levels by silencing miR-296-5p and miR-512-5p expression, thereby contributing to the aggressiveness of basal type breast cancer.
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Affiliation(s)
- Roberto Dinami
- Laboratorio Nazionale Consorzio Interuniversitario Biotecnologie (LNCIB), Genomic Stability Unit, Trieste 34149, Italy.,Italian National Cancer Institute, Regina Elena, Rome 00144, Italy
| | - Valentina Buemi
- Laboratorio Nazionale Consorzio Interuniversitario Biotecnologie (LNCIB), Genomic Stability Unit, Trieste 34149, Italy.,Department of Life Sciences, Università degli Studi di Trieste, Trieste 34127, Italy
| | - Rosanna Sestito
- Italian National Cancer Institute, Regina Elena, Rome 00144, Italy
| | - Antonina Zappone
- Laboratorio Nazionale Consorzio Interuniversitario Biotecnologie (LNCIB), Genomic Stability Unit, Trieste 34149, Italy.,Department of Life Sciences, Università degli Studi di Trieste, Trieste 34127, Italy
| | - Yari Ciani
- Laboratorio Nazionale Consorzio Interuniversitario Biotecnologie (LNCIB), Bioinformatics and Functional Genomics Unit (BFGU), Trieste 34149, Italy
| | - Miguel Mano
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Molecular Medicine Laboratory, Trieste 34149, Italy
| | - Eleonora Petti
- Laboratorio Nazionale Consorzio Interuniversitario Biotecnologie (LNCIB), Genomic Stability Unit, Trieste 34149, Italy.,Italian National Cancer Institute, Regina Elena, Rome 00144, Italy.,Department of Life Sciences, Università degli Studi di Trieste, Trieste 34127, Italy
| | - Andrea Sacconi
- Italian National Cancer Institute, Regina Elena, Translational Oncogenomics Group, Rome 00144, Italy
| | - Giovanni Blandino
- Italian National Cancer Institute, Regina Elena, Translational Oncogenomics Group, Rome 00144, Italy
| | - Mauro Giacca
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Molecular Medicine Laboratory, Trieste 34149, Italy
| | - Silvano Piazza
- Laboratorio Nazionale Consorzio Interuniversitario Biotecnologie (LNCIB), Bioinformatics and Functional Genomics Unit (BFGU), Trieste 34149, Italy
| | - Roberta Benetti
- Laboratorio Nazionale Consorzio Interuniversitario Biotecnologie (LNCIB), Cancer Epigenetics Unit, Trieste 34149, Italy.,Department of Medical and Biological Sciences, Università degli Studi di Udine, Udine 33100, Italy
| | - Stefan Schoeftner
- Laboratorio Nazionale Consorzio Interuniversitario Biotecnologie (LNCIB), Genomic Stability Unit, Trieste 34149, Italy.,Italian National Cancer Institute, Regina Elena, Rome 00144, Italy.,Department of Life Sciences, Università degli Studi di Trieste, Trieste 34127, Italy
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5
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Kulić A, Plavetić ND, Gamulin S, Jakić-Razumović J, Vrbanec D, Sirotković-Skerlev M. Telomerase activity in breast cancer patients: association with poor prognosis and more aggressive phenotype. Med Oncol 2016; 33:23. [PMID: 26833480 DOI: 10.1007/s12032-016-0736-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2015] [Accepted: 01/18/2016] [Indexed: 11/28/2022]
Abstract
Telomerase expression is an important mechanism of tumor unlimited replicative potential. The aim of this study was to evaluate prognostic impact of telomerase activity in breast cancer patients and to correlate telomerase activity with established prognostic factors. We analyzed tissue of 102 malignant breast lesions and 20 healthy breast tissues. Telomerase activity was determined by telomeric repeat amplification protocol assay. Telomerase activity was present in 77 (75.49 %) of 102 breast cancers. Telomerase activity in breast cancers was statistically significantly higher in comparison with the activity in normal breast tissue. The levels of telomerase activity were significantly positively correlated with tumor size, axillary nodal status, histological grade, HER-2/neu protein expression in tumor tissue and expression of the nuclear antigen Ki-67. A statistically significant negative correlation was found between the presence of ER and telomerase activity. There was no correlation between telomerase activity and concentration of PR or the age of patients. Kaplan-Meier analysis showed that patients with higher telomerase activity had significantly shorter 10-year disease-free survival (p < 0.0001) and 10-year overall survival (p < 0.0001) than those with lower telomerase activity. These results were confirmed by logistic regression analysis. Our results support the prognostic role of telomerase activity and its relationship with the more aggressive phenotype of breast cancer.
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Affiliation(s)
- Ana Kulić
- Department of Oncology, Division of Pathophysiology and Experimental Oncology, University Hospital Center Zagreb, Kišpatićeva 12, 10000, Zagreb, Croatia
| | - Natalija Dedić Plavetić
- Department of Oncology, Division of Medical Oncology, University Hospital Center Zagreb, Zagreb, Croatia.,School of Medicine, University of Zagreb, Zagreb, Croatia
| | | | - Jasminka Jakić-Razumović
- Department of Pathology, University Hospital Center Zagreb, Zagreb, Croatia.,School of Medicine, University of Zagreb, Zagreb, Croatia
| | - Damir Vrbanec
- Department of Oncology, Division of Medical Oncology, University Hospital Center Zagreb, Zagreb, Croatia.,School of Medicine, University of Zagreb, Zagreb, Croatia
| | - Maja Sirotković-Skerlev
- Department of Oncology, Division of Pathophysiology and Experimental Oncology, University Hospital Center Zagreb, Kišpatićeva 12, 10000, Zagreb, Croatia. .,School of Medicine, University of Zagreb, Zagreb, Croatia.
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6
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Reddel RR. Telomere maintenance mechanisms in cancer: clinical implications. Curr Pharm Des 2015; 20:6361-74. [PMID: 24975603 PMCID: PMC4262939 DOI: 10.2174/1381612820666140630101047] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Accepted: 06/26/2014] [Indexed: 01/20/2023]
Abstract
The presence of immortal cell populations with an up-regulated telomere maintenance mechanism (TMM) is an almost universal characteristic of cancers, whereas normal somatic cells are unable to prevent proliferation-associated telomere shortening and have a limited proliferative potential. TMMs and related aspects of telomere structure and function therefore appear to be ideal targets for the development of anticancer therapeutics. Such treatments would be targeted to a specific cancer-related molecular abnormality, and also be broad-spectrum in that they would be expected to be potentially applicable to most cancers. However, the telomere biology of normal and malignant human cells is a relatively young research field with large numbers of unanswered questions, so the optimal design of TMM-targeted therapeutic approaches remains unclear. This review outlines the opportunities and challenges presented by telomeres and TMMs for clinical management of cancer.
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Affiliation(s)
- Roger R Reddel
- Children's Medical Research Institute, 214 Hawkesbury Road, Westmead, New South Wales 2145, Australia.
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7
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Wan Kamarul Zaman WS, Makpol S, Sathapan S, Chua KH. Long-termin vitroexpansion of human adipose-derived stem cells showed low risk of tumourigenicity. J Tissue Eng Regen Med 2012; 8:67-76. [DOI: 10.1002/term.1501] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Revised: 01/20/2012] [Accepted: 01/25/2012] [Indexed: 11/11/2022]
Affiliation(s)
| | - Suzana Makpol
- Department of Biochemistry, Faculty of Medicine; Universiti Kebangsaan Malaysia; Kuala Lumpur Malaysia
| | | | - Kien Hui Chua
- Department of Physiology, Faculty of Medicine; Universiti Kebangsaan Malaysia; Kuala Lumpur Malaysia
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8
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Lønne GK, Cornmark L, Zahirovic IO, Landberg G, Jirström K, Larsson C. PKCalpha expression is a marker for breast cancer aggressiveness. Mol Cancer 2010; 9:76. [PMID: 20398285 PMCID: PMC2873434 DOI: 10.1186/1476-4598-9-76] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Accepted: 04/14/2010] [Indexed: 11/23/2022] Open
Abstract
Background Protein kinase C (PKC) isoforms are potential targets for breast cancer therapy. This study was designed to evaluate which PKC isoforms might be optimal targets for different breast cancer subtypes. Results In two cohorts of primary breast cancers, PKCα levels correlated to estrogen and progesterone receptor negativity, tumor grade, and proliferative activity, whereas PKCδ and PKCε did not correlate to clinicopathological parameters. Patients with PKCα-positive tumors showed poorer survival than patients with PKCα-negative tumors independently of other factors. Cell line studies demonstrated that PKCα levels are high in MDA-MB-231 and absent in T47D cells which proliferated slower than other cell lines. Furthermore, PKCα silencing reduced proliferation of MDA-MB-231 cells. PKCα inhibition or downregulation also reduced cell migration in vitro. Conclusions PKCα is a marker for poor prognosis of breast cancer and correlates to and is important for cell functions associated with breast cancer progression.
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Affiliation(s)
- Gry Kalstad Lønne
- Center for Molecular Pathology, Department of Laboratory Medicine, Lund University, Malmö University Hospital, SE- 205 02 Malmö, Sweden.
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9
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Poonepalli A, Banerjee B, Ramnarayanan K, Palanisamy N, Putti TC, Hande MP. Telomere-mediated genomic instability and the clinico-pathological parameters in breast cancer. Genes Chromosomes Cancer 2008; 47:1098-109. [DOI: 10.1002/gcc.20608] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
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10
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Brennan DJ, Rexhepaj E, O'Brien SL, McSherry E, O'Connor DP, Fagan A, Culhane AC, Higgins DG, Jirstrom K, Millikan RC, Landberg G, Duffy MJ, Hewitt SM, Gallagher WM. Altered cytoplasmic-to-nuclear ratio of survivin is a prognostic indicator in breast cancer. Clin Cancer Res 2008; 14:2681-9. [PMID: 18451232 DOI: 10.1158/1078-0432.ccr-07-1760] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
PURPOSE Survivin (BIRC5) is a promising tumor biomarker. Conflicting data exist on its prognostic effect in breast cancer. These data may at least be partly due to the manual interpretation of immunohistochemical staining, especially as survivin can be located in both the nucleus and cytoplasm. Quantitative determination of survivin expression using image analysis offers the opportunity to develop alternative scoring models for survivin immunohistochemistry. Here, we present such a model. EXPERIMENTAL DESIGN A breast cancer tissue microarray containing 102 tumors was stained with an anti-survivin antibody. Whole-slide scanning was used to capture high-resolution images. These images were analyzed using automated algorithms to quantify the staining. RESULTS Increased nuclear, but not cytoplasmic, survivin was associated with a reduced overall survival (OS; P = 0.038) and disease-specific survival (P = 0.0015). A high cytoplasmic-to-nuclear ratio (CNR) of survivin was associated with improved OS (P = 0.005) and disease-specific survival (P = 0.05). Multivariate analysis revealed that the survivin CNR was an independent predictor of OS (hazard ratio, 0.09; 95% confidence interval, 0.01-0.76; P = 0.027). A survivin CNR of >5 correlated positively with estrogen receptor (P = 0.019) and progesterone receptor (P = 0.033) levels, whereas it was negatively associated with Ki-67 expression (P = 0.04), p53 status (P = 0.005), and c-myc amplification (P = 0.016). CONCLUSION Different prognostic information is supplied by nuclear and cytoplasmic survivin in breast cancer. Nuclear survivin is a poor prognostic marker in breast cancer. Moreover, CNR of survivin, as determined by image analysis, is an independent prognostic factor.
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Affiliation(s)
- Donal J Brennan
- UCD School of Biomolecular and Biomedical Science and UCD School of Medicine and Medical Science, UCD Conway Institute, University College Dublin, Belfield, Dublin, Ireland
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11
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Bodvarsdóttir SK, Steinarsdóttir M, Hilmarsdóttir H, Jónasson JG, Eyfjörd JE. MYC amplification and TERT expression in breast tumor progression. ACTA ACUST UNITED AC 2008; 176:93-9. [PMID: 17656250 DOI: 10.1016/j.cancergencyto.2007.04.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2007] [Revised: 03/30/2007] [Accepted: 04/02/2007] [Indexed: 02/05/2023]
Abstract
The complex roles of genomic instability, MYC oncogene amplification, activation of telomerase, and p53 function still remain to be fully described in breast tumors. MYC stimulates the telomerase catalytic subunit, TERT, which interacts with p53. Oncogene MYC amplification analysis was performed on 27 paraffin-embedded breast tumor samples by fluorescence in situ hybridization, selected on the basis of chromosomal instability. TERT immunostaining was performed on a larger group of breast tumor sections. All tumor samples were analyzed for TP53 mutation, genomic index, S-phase fraction, and pathological stages. Amplification of MYC was detected in 16 of 27 tumors (59%) and found to be associated with TNM stages I and II (P = 0.018), genomic index > 1.5 (P = 0.033), and S-phase fraction > 5% (P = 0.020). No association was found between MYC amplification and TERT immunostaining or TP53 mutations. Analysis of TERT in 103 primary breast tumors showed > 50% nuclei immunostaining in 58% of cases. High TERT immunostaining associated with genomic index > 1.5 (P = 0.017), high S-phase fraction (P = 0.056), and TP53 mutations (P = 0.030). No association was found between TERT staining and TNM stages. This study supports early involvement of MYC amplification in breast tumor progression. Both MYC amplification and TERT expression appear to be associated with high genomic instability and proliferation. TERT association with TP53 mutations indicates that TERT activity is downregulated by functional p53 protein in breast tumors.
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12
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O’Brien SL, Fagan A, Fox EJ, Millikan RC, Culhane AC, Brennan DJ, McCann AH, Hegarty S, Moyna S, Duffy MJ, Higgins DG, Jirström K, Landberg G, Gallagher WM. CENP-F expression is associated with poor prognosis and chromosomal instability in patients with primary breast cancer. Int J Cancer 2007; 120:1434-43. [PMID: 17205517 PMCID: PMC4972098 DOI: 10.1002/ijc.22413] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
DNA microarrays have the potential to classify tumors according to their transcriptome. Tissue microarrays (TMAs) facilitate the validation of biomarkers by offering a high-throughput approach to sample analysis. We reanalyzed a high profile breast cancer DNA microarray dataset containing 96 tumor samples using a powerful statistical approach, between group analyses. Among the genes we identified was centromere protein-F (CENP-F), a gene associated with poor prognosis. In a published follow-up breast cancer DNA microarray study, comprising 295 tumour samples, we found that CENP-F upregulation was significantly associated with worse overall survival (p<0.001) and reduced metastasis-free survival (p<0.001). To validate and expand upon these findings, we used 2 independent breast cancer patient cohorts represented on TMAs. CENP-F protein expression was evaluated by immunohistochemistry in 91 primary breast cancer samples from cohort I and 289 samples from cohort II. CENP-F correlated with markers of aggressive tumor behavior including ER negativity and high tumor grade. In cohort I, CENP-F was significantly associated with markers of CIN including cyclin E, increased telomerase activity, c-Myc amplification and aneuploidy. In cohort II, CENP-F correlated with VEGFR2, phosphorylated Ets-2 and Ki67, and in multivariate analysis, was an independent predictor of worse breast cancer-specific survival (p=0.036) and overall survival (p=0.040). In conclusion, we identified CENP-F as a biomarker associated with poor outcome in breast cancer and showed several novel associations of biological significance.
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Affiliation(s)
- Sallyann L. O’Brien
- UCD School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Belfield, Dublin, Ireland
| | - Ailís Fagan
- UCD School of Medicine and Medical Science, Conway Institute, University College Dublin, Belfield, Dublin, Ireland
| | - Edward J.P. Fox
- UCD School of Medicine and Medical Science, Conway Institute, University College Dublin, Belfield, Dublin, Ireland
| | - Robert C. Millikan
- Department of Epidemiology, University of North Carolina, Chapel Hill, NC, USA
| | - Aedín C. Culhane
- UCD School of Medicine and Medical Science, Conway Institute, University College Dublin, Belfield, Dublin, Ireland
| | - Donal J. Brennan
- UCD School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Belfield, Dublin, Ireland
| | - Amanda H. McCann
- UCD School of Medicine and Medical Science, Conway Institute, University College Dublin, Belfield, Dublin, Ireland
| | - Shauna Hegarty
- UCD School of Medicine and Medical Science, Conway Institute, University College Dublin, Belfield, Dublin, Ireland
| | - Siobhan Moyna
- UCD School of Medicine and Medical Science, Conway Institute, University College Dublin, Belfield, Dublin, Ireland
| | - Michael J. Duffy
- UCD School of Medicine and Medical Science, Conway Institute, University College Dublin, Belfield, Dublin, Ireland
| | - Desmond G. Higgins
- UCD School of Medicine and Medical Science, Conway Institute, University College Dublin, Belfield, Dublin, Ireland
| | - Karin Jirström
- Division of Pathology, Department of Laboratory Medicine, Lund University, Malmö University Hospital, Malmö, Sweden
| | - Göran Landberg
- Division of Pathology, Department of Laboratory Medicine, Lund University, Malmö University Hospital, Malmö, Sweden
| | - William M. Gallagher
- UCD School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Belfield, Dublin, Ireland
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13
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Shin JS, Hong A, Solomon MJ, Lee CS. The role of telomeres and telomerase in the pathology of human cancer and aging. Pathology 2006; 38:103-13. [PMID: 16581649 DOI: 10.1080/00313020600580468] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Cellular senescence, the state of permanent growth arrest, is the inevitable fate of replicating normal somatic cells. Postulated to underlie this finite replicative span is the physiology of telomeres, which constitute the ends of chromosomes. The repetitive sequences of these DNA-protein complexes progressively shorten with each mitosis. When the critical length is bridged, telomeres trigger DNA repair and cell cycle checkpoint mechanisms that result in chromosomal fusions, cell cycle arrest, senescence and/or apoptosis. Should senescence be bypassed at such time, continued cell divisions in the face of dysfunctional telomeres and activated DNA repair machinery can result in the genomic instability favourable for oncogenesis. The longevity and malignant progression of the thus transformed cell requires coincident telomerase expression or other means to negate the constitutional telomeric loss. Practically then, telomeres and telomerase may represent plausible prognostic and screening cancer markers. Furthermore, if the argument is extended, with assumptions that telomeric attrition is indeed the basis of cellular senescence and that accumulation of the latter equates to aging at the organismal level, then telomeres may well explain the increased incidence of cancer with human aging.
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Affiliation(s)
- Joo-Shik Shin
- Department of Anatomical Pathology, Royal Prince Alfred Hospital, Camperdown, Australia.
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14
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Choi SH, Im E, Kang HK, Lee JH, Kwak HS, Bae YT, Park HJ, Kim ND. Inhibitory effects of costunolide on the telomerase activity in human breast carcinoma cells. Cancer Lett 2005; 227:153-62. [PMID: 16112418 DOI: 10.1016/j.canlet.2005.01.011] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2004] [Revised: 01/07/2005] [Accepted: 01/10/2005] [Indexed: 11/29/2022]
Abstract
Costunolide, a natural sesquiterpene compound, has been known having cytotoxic and chemopreventive effects on various human cancer cells. In the present study, we examined the effects of costunolide on telomerase activity and on the components of telomerase in MCF-7 (wild-type p53) and MDA-MB-231 (mutant p53) cells. We found that costunolide inhibited the growth and telomerase activity of MCF-7 and MDA-MB-231 cells in a concentration- and time-dependent manner. The expression of hTERT mRNA was also inhibited but hTR mRNA was not. In addition, the bindings of transcription factors in hTERT promoters were significantly decreased in both cells by the treatment of costunolide. These results suggest that costunolide inhibited the growth of both MCF-7 and MDA-MB-231 cells and this effect was mediated at least in part by a significant reduction in telomerase activity.
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Affiliation(s)
- Sang-Ho Choi
- Department of Pharmacy, College of Pharmacy, and Research Institute for Drug Development, Pusan National University, Busan 609-735, South Korea
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Nofech-Mozes S, Spayne J, Rakovitch E, Hanna W. Prognostic and predictive molecular markers in DCIS: a review. Adv Anat Pathol 2005; 12:256-64. [PMID: 16210921 DOI: 10.1097/01.pap.0000184177.65919.5e] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Eighteen percent of all new breast cancers detected on screening mammography are ductal carcinoma in situ (DCIS), a preinvasive lesion that is highly curable. However, some women with DCIS will develop life-threatening invasive breast cancer. Because the determinants of invasive recurrence are unknown, all women with DCIS require the same treatment (usually with surgery and radiation). Therefore, there is a need to identify biologic markers and create a profile that will provide prognostic information that is more accurate than the currently used van Nuys Index to predict invasive recurrence. In the present review, we examined the many biologic markers studied in breast cancer, describe their main biologic role and their expression in DCIS, and review the various studies regarding their ability to serve as prognostic factors in breast cancer with an emphasis on predicting invasive recurrence in patients with DCIS. This review covers established markers, namely, ER, PR and HER2/neu, that are used routinely to make treatment decisions as well as investigative biologic factors involved in cell proliferation, cell cycle regulation, extracellular molecules, factors involved in extracellular matrix degradation, and angiogenesis. However, controversies exist regarding the value of these prognostic factors, their interrelationship, and their advantages over morphologic evaluation.
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Affiliation(s)
- Sharon Nofech-Mozes
- Department of Pathology, Sunnybrook and Women's College Health Sciences Center, Toronto, Ontario, Canada
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16
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Landberg G, Nilsson K, Jirström K, Rydén L, Kitching R, Burger AM, Seth A. Cyclin I is expressed in human breast cancer and closely associated with VEGF and KDR expression. Breast Cancer Res Treat 2005; 89:313-6. [PMID: 15754132 DOI: 10.1007/s10549-004-2230-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
In the present study, cyclin I protein expression in 114 invasive human breast cancers was correlated with cell cycle and angiogenesis-related proteins and clinico-pathological data. A strong association was found between cytoplasmic cyclin I staining and VEGF (p = 0.001) as well as the VEGF receptor KDR (p = 0.001), suggesting a link between cyclin I and angiogenesis.
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Affiliation(s)
- Göran Landberg
- Division of Pathology, Department of Laboratory Medicine, U-MAS, Lund University, Malmö, Sweden
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17
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Shats I, Milyavsky M, Tang X, Stambolsky P, Erez N, Brosh R, Kogan I, Braunstein I, Tzukerman M, Ginsberg D, Rotter V. p53-dependent down-regulation of telomerase is mediated by p21waf1. J Biol Chem 2004; 279:50976-85. [PMID: 15371422 DOI: 10.1074/jbc.m402502200] [Citation(s) in RCA: 108] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Inactivation of p53 and activation of telomerase occur in the majority of human cancers, raising the possibility of a link between these two pathways. Overexpression of wild-type p53 down-regulates the enzymatic activity of telomerase in various cancer cell lines through transcriptional repression of its catalytic subunit, human telomerase reverse transcriptase (hTERT). In this study, we re-evaluated the role of p53 in telomerase regulation using isogenic cell lines expressing physiological levels of p53. We demonstrate that endogenous wild-type p53 was able to down-regulate telomerase activity, hTERT mRNA levels, and promoter activity; however, the ability to repress hTERT expression was found to be cell type-specific. The integrity of the DNA-binding core domain, the N-terminal transactivation domain, and the C-terminal oligomerization domains of p53 was essential for hTERT promoter repression, whereas the proline-rich domain and the extreme C terminus were not required. Southwestern and chromatin immunoprecipitation experiments demonstrated lack of p53 binding to the hTERT promoter, raising the possibility of an indirect repressive mechanism. The down-regulation of hTERT promoter activity was abolished by a dominant-negative E2F1 mutant. Mutational analysis identified a specific E2F site responsible for p53-mediated repression. Knockdown of the key p53 transcriptional target, p21, was sufficient to eliminate the p53-dependent repression of hTERT. Inactivation of the Rb family using either viral oncoproteins or RNA interference attenuated the repression. Inhibition of histone deacetylases also interfered with the repression of hTERT by p53. Therefore, our results suggest that repression of hTERT by endogenous p53 is mediated by p21 and E2F.
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Affiliation(s)
- Igor Shats
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel
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18
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Abstract
Human chromosomes have highly specialized structures at their ends termed telomeres, repetitive, non-coding DNA sequences (5'-TTAGGG-3'), ranging in size from 5 to 20 kb in human cells. These highly specialized structures prevent chromosome ends from being recognized as double-strand DNA breaks, and they also provide protection from destabilizing agents. The mechanism for maintaining telomere integrity is controlled by telomerase, a ribonucleoprotein enzyme that specifically restores telomere sequences lost during replication by using an intrinsic RNA component as a template for polymerization. Telomerase has two core functional components required for its activity: the catalytic subunit of human telomerase reverse transcriptase (hTERT) and a telomerase RNA template (hTR). Telomerase is activated in the majority of immortal cell lines in culture and in most malignant tumors. This review outlines our current understanding of telomerase in breast cancer development and critically evaluates potential utilities in diagnosis, prognosis, and therapy.
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Affiliation(s)
- Atac Baykal
- University of Texas M.D. Anderson Cancer Center, Department of Pathology, Houston, Texas, USA
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19
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Nakashima H, Nishida Y, Sugiura H, Katagiri H, Yonekawa M, Yamada Y, Iwata H, Nagasaka T, Ishiguro N. Telomerase, p53 and PCNA activity in osteosarcoma. EUROPEAN JOURNAL OF SURGICAL ONCOLOGY 2003; 29:564-7. [PMID: 12943619 DOI: 10.1016/s0748-7983(03)00117-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
AIMS The aim of this study was to investigate telomerase activity and to assess the correlation between telomerase activity, tumor proliferative activity and p53 overexpression in osteosarcoma tumor samples. METHODS Using a telomerase polymerase chain reaction-enzyme-linked immunoassay based on the telomeric repeat amplification protocol method, we examined telomerase activity in 26 primary osteosarcoma specimens. P53 overexpression was identified using immunohistochemical staining, and tumor proliferative activity was assessed by immunohistochemical staining of PCNA. RESULTS Telomerase activity was detected at a relatively low level in five of 26 osteosarcoma tissue specimens. P53 was detected in eight of 21 cases. There was no significant correlation between telomerase activity and p53 overexpression (p=0.325). There was a significant correlation between PCNA staining and telomerase activity (p=0.0075). CONCLUSION Difference between the telomerase activity and p53 overexpression in osteosarcoma suggests that p53 and telomerase may not cooperate in tumor proliferation. Correlation of telomerase activity to PCNA expression suggests that telomerase activity may also useful for evaluate proliferative activity in osteosarcoma.
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Affiliation(s)
- H Nakashima
- Department of Orthopaedic Surgery, Nagoya University School of Medicine, Nagoya, Japan.
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20
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Stampfer MR, Garbe J, Nijjar T, Wigington D, Swisshelm K, Yaswen P. Loss of p53 function accelerates acquisition of telomerase activity in indefinite lifespan human mammary epithelial cell lines. Oncogene 2003; 22:5238-51. [PMID: 12917625 DOI: 10.1038/sj.onc.1206667] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We describe novel effects of p53 loss on immortal transformation, based upon comparison of immortally transformed human mammary epithelial cell (HMEC) lines lacking functional p53 with closely related p53(+) lines. Our previous studies of p53(+) immortal HMEC lines indicated that overcoming the stringent replicative senescence step associated with critically short telomeres (agonescence), produced indefinite lifespan lines that maintained growth without immediately expressing telomerase activity. These telomerase(-) 'conditionally immortal' HMEC underwent an additional step, termed conversion, to become fully immortal telomerase(+) lines with uniform good growth. The very gradual conversion process was associated with slow heterogeneous growth and high expression of the cyclin-dependent kinase inhibitor p57(Kip2). We now show that p53 suppresses telomerase activity and is necessary for the p57 expression in early passage p53(+) conditionally immortal HMEC lines, and that p53(-/-) lines exhibit telomerase reactivation and attain full immortality much more rapidly. A p53-inhibiting genetic suppressor element introduced into early passages of a conditionally immortal telomerase(-) p53(+) HMEC line led to rapid induction of hTERT mRNA, expression of telomerase activity, loss of p57 expression, and quick attainment of uniform good growth. These studies indicate that derangements in p53 function may impact malignant progression through direct effects on the conversion process, a potentially rate-limiting step in HMEC acquisition of uniform unlimited growth potential. These studies also provide evidence that the function of p53 in suppression of telomerase activity is separable from its cell cycle checkpoint function.
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Affiliation(s)
- Martha R Stampfer
- Lawrence Berkeley National Laboratory, Life Sciences Division, Berkeley, CA 94720, USA.
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21
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Abstract
Human epithelial cells encounter two senescence barriers that enforce a limited proliferative potential. A first barrier is mediated by the retinoblastoma protein, and can be overcome by multiple types of errors, many of which are observed in human cancers. A second, extremely stringent telomere-dependent barrier, is a consequence of repression of telomerase activity. Although relieved by ectopic hTERT expression, the nature of the errors required to overcome this latter barrier during in vivo carcinogenesis have not yet been defined. Attainment of immortality and telomerase reactivation are crucial to human carcinoma development; the derangements responsible for attainment of immortality may be rate-limiting and permissive for further progression to malignancy.
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22
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Ahmed A, Tollefsbol T. Telomeres, telomerase, and telomerase inhibition: clinical implications for cancer. J Am Geriatr Soc 2003; 51:116-22. [PMID: 12534855 DOI: 10.1034/j.1601-5215.2002.51019.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Telomeres are located at the ends of eukaryotic chromosomes. The enzyme telomerase synthesized them, and they are responsible for maintaining the lengths of chromosomes. Absence of telomerase is associated with telomere shortening and aging of somatic cells, but high telomerase activity is observed in over 90% of human cancer cells. Although the disappearance of telomerase with aging is considered a natural defense against development of cancer, it is not known what triggers the reappearance of telomerase in cancer cells. Telomerase activity is directly correlated with the expression of its active catalytic component, the human telomerase reverse transcriptase (hTERT), which is controlled primarily at the level of transcription. An earlier paper discussed the relationship of telomerase with aging. In this article, the contemporary literature is reviewed to explore the associations between telomerase, telomerase inhibition, and cancer. Because most cancers occur in old age, with the aging of the population, the number of people suffering from cancer is expected to increase in the coming decades. It is not known what roles telomerase and hTERT play in the complex relationship between aging and cancer. Data from experimental studies suggest that telomerase assay could potentially play a role in the diagnosis and prognosis of cancers. There is also evidence that telomerase inhibitors might be used as anticancer agents. As the knowledge of the relationships between telomerase and cancer and between telomerase and aging advances, it is hoped that more about the interacting relationships between telomerase, aging, and cancer will be learned.
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Affiliation(s)
- Ali Ahmed
- Division of Gerontology and Geriatric Medicine, Department of Medicine, School of Medicine, University of Alabama at Birmingham and Heart Failure Clinic and Section of Gerontology, VA Medical Center, Birmingham, Alabama 35294-2041, USA.
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23
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Abstract
OBJECTIVES [corrected] Genomic instability is a driving force for tumorigenesis. Telomerase and p53 play central roles in maintaining genomic integrity. The purpose of this study was to assess the role of telomerase expression and p53 protein overexpression in hepatocellular carcinoma (HCC). METHODS Telomerase activity and p53 overexpression were investigated in 63 patients undergoing hepatectomy for HCC by a telomeric repeat amplification protocol and immunohistochemistry, respectively. The associations among telomerase expression, p53 overexpression, and clinicopathological features were analyzed, and independent prognostic factors in the recurrence of HCC after hepatectomy were determined. RESULTS Telomerase expression did not correlate with clinicopathological features except hepatitis virus status (p = 0.04) and was identified as a significant prognostic variable for HCC recurrence (p = 0.027) along with portal venous invasion (p = 0.001). In contrast, p53 overexpression strongly correlated with tumor differentiation (p < 0.0001) but did not reflect time to recurrence (p = 0.26). Telomerase expression did not correlate with p53 overexpression (p = 0.35). CONCLUSIONS The reactivation of telomerase was of significant value in predicting the recurrence of HCC after hepatectomy. However, p53 overexpression did not correlate with telomerase expression in HCC, nor did it reflect the time to recurrence.
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Affiliation(s)
- Takashi Kobayashi
- Hepato-Biliary-Pancreatic Surgery Division, Department of Surgery, Graduate School of Medicine, University of Tokyo, Tokyo, Japan
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24
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Poremba C, Heine B, Diallo R, Heinecke A, Wai D, Schaefer KL, Braun Y, Schuck A, Lanvers C, Bànkfalvi A, Kneif S, Torhorst J, Zuber M, Köchli OR, Mross F, Dieterich H, Sauter G, Stein H, Fogt F, Boecker W. Telomerase as a prognostic marker in breast cancer: high-throughput tissue microarray analysis of hTERT and hTR. J Pathol 2002; 198:181-9. [PMID: 12237877 DOI: 10.1002/path.1191] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Telomerase activity (TA) has been shown to correlate with poor clinical outcome in various tumour entities, indicating that tumours expressing this enzyme may be more aggressive and that TA may be a useful prognostic marker. For breast cancer, however, TA is a controversial prognostic marker; whereas some studies suggest an association between TA and disease outcome, others do not find this association. This study used tissue microarrays (breast carcinoma prognosis arrays) containing 611 samples (each 0.6 mm in diameter) from the tumour centre of paraffin-embedded breast carcinomas to analyse the catalytic subunit of telomerase, human telomerase reverse-transcriptase (hTERT), and the internal RNA component (hTR), which are the core components of the telomerase holoenzyme complex. hTERT protein expression was obtained by immunohistochemistry (human anti-telomerase antibody Ab-2, Calbiochem), and hTR RNA was measured by radioactive in situ hybridization. hTERT and hTR expression were determined semi-quantitatively and graded (scores 1-4). Clinical data, such as histological subtype, pT stage, tumour diameter, pN stage, BRE grade, tumour-specific survival (in months), patient's age and others, were available for statistical analysis. A statistically significant correlation was found between tumour-specific survival (overall survival) and hTERT expression (p < 0.0001) or hTR expression (p = 0.00110). Tumours with higher scores (scores 3, 4) for hTR and/or hTERT were associated with a worse prognosis. In multivariate analysis, hTERT expression was an independent prognostic factor. Previous studies, focusing on analysis of TA in smaller numbers of fresh-frozen breast carcinomas by the TRAP assay, gave controversial results with respect to TA as a prognostic marker. Using tissue microarrays from 611 breast carcinomas, this study has demonstrated that increased expression levels of the telomerase core components, hTERT and hTR, are associated with lower overall survival. These findings suggest that TA should be included in future validation studies as a prognostic marker in breast cancer.
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Affiliation(s)
- Christopher Poremba
- Gerhard-Domagk-Institute of Pathology, Westfälische Wilhelms-University, Domagkstrasse 17, 48149 Münster, Germany
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25
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Lodén M, Stighall M, Nielsen NH, Roos G, Emdin SO, Ostlund H, Landberg G. The cyclin D1 high and cyclin E high subgroups of breast cancer: separate pathways in tumorogenesis based on pattern of genetic aberrations and inactivation of the pRb node. Oncogene 2002; 21:4680-90. [PMID: 12096344 DOI: 10.1038/sj.onc.1205578] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2001] [Revised: 04/15/2002] [Accepted: 04/15/2002] [Indexed: 11/09/2022]
Abstract
In an attempt to identify subtypes of breast cancer and pinpoint patterns of cell cycle regulatory defects associated with clinical behaviour, proliferation and other transformation associated events, a multitude of cell cycle regulatory proteins were analysed in a material of 113 primary breast cancers. Increased proliferation was observed in two different scenarios; (1) with high cyclin D1 and elevated retinoblastoma protein (pRb) phosphorylation, (cyclin D1(high) tumours) or (2) with high cyclin E protein but low cyclin D1 and lack of corresponding pRb phosphorylation (cyclin E(high) tumours) indicative of an interrupted pRb pathway. Characteristic for cyclin E(high) tumours were further defects in p53, p27 and bcl-2, while c-erbB2 overexpression and c-myc amplification was found in both cyclin D1(high) and E(high) tumours. Using transfected cell lines overexpressing cyclin E, cyclin E(high) and D1(high) tumours were mimicked and the cyclin D1(high) cell line normalized the cyclin E kinase activity by an induction and redirection of p21 and p27 to the cyclin E complex whereas cyclin E(high) cell lines obtained increased kinase activity without redirection of inhibitors. Based on differences in genetic aberrations as well as function of the pRb node we therefore propose a model in which cyclin D1(high) and cyclin E(high) tumours represent two alternative mechanisms to inactivate the pRb pathway and thereby achieve unrestrained growth in the tumorogenesis of breast cancer.
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Affiliation(s)
- Martin Lodén
- Department of Pathology, Umeå University, S-901 87 Umeå, Sweden
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26
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Elkak AE, Kirkpatrick K, Mears L, Wells C, Ghilchik M, Newbold R, Mokbel K. Telomerase activity and Bcl-2 expression in human breast cancer. EUROPEAN JOURNAL OF SURGICAL ONCOLOGY 2002; 28:14-8. [PMID: 11869007 DOI: 10.1053/ejso.2001.1186] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
AIMS Telomerase is a ribonucleoprotein that synthesizes telomeres and plays an important role in cellular immortalization. Bcl-2 gene encodes for a mitochondrial protein thought to prevent apoptosis of normal cells. We previously reported telomerase activity in 74% of human invasive breast cancers and detected a significant association between telomerase activity and prognostic parameters such as nodal status, tumour size and cellular proliferation. We hypothesized that telomerase reactivation in human breast cancer was associated with increased immunohistochemical expression of Bcl-2. METHODS Bcl-2 immunohistochemical expression was determined in 25 infiltrating breast carcinomas with known telomerase activity (17 telomerase-positive and 8 telomerase-negative). The percentage of strongly and moderately stained tumour cells for Bcl-2 was determined by a breast pathologist who was blinded to telomerase data. Fisher's exact test was used to examine the association between telomerase activity and Bcl-2 expression. RESULTS The median percentage of strongly stained tumour cells was 50% for telomerase-positive tumours (range, 0--100%) and 45% for telomerase-negative tumours (range, 0--100%). Twelve (70%) of 17 telomerase-positive tumours expressed strong or moderate Bcl-2 staining in >50% of tumour cells compared with six (75%) of eight telomerase-negative tumours (P=1.0). CONCLUSION Telomerase reactivation seems to be independent of Bcl-2 protein expression in human breast cancer.
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Affiliation(s)
- A E Elkak
- The Breast Cancer Centre, St George's Hospital and Medical School, Blackshaw Road, London, SW17 0QT, UK
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27
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Dalla Torre CA, Maciel RMB, Pinheiro NA, Andrade JAD, De Toledo SRC, Villa LL, Cerutti JM. TRAP-silver staining, a highly sensitive assay for measuring telomerase activity in tumor tissue and cell lines. Braz J Med Biol Res 2002; 35:65-8. [PMID: 11743616 DOI: 10.1590/s0100-879x2002000100009] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Measurement of telomerase activity in clinically obtained tumor samples may provide important information for use as both a diagnostic marker and a prognostic indicator for patient outcome. In order to evaluate telomerase activity in tumor tissue without radiolabeling the product, we developed a simple telomeric repeat amplification protocol-silver-staining assay that is less time-consuming, is safe and requires minimal equipment. In addition, we determined the sensitivity of the silver-staining method by using extracts of telomerase-positive thyroid carcinoma cell lines which were serially diluted from 5,000 to 10 cells. Telomerase activity was also assayed in 19 thyroid tumors, 2 normal controls and 27 bone marrow aspirates. The results indicate that the technique permits the detection of telomerase activity from 5000 to as few as 10 cells. We propose that it could be immediately applicable in many laboratories due to the minimal amount of equipment required.
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Affiliation(s)
- C A Dalla Torre
- Divisão de Genética, Departamento de Morfologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, SP, Brasil
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28
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Krams M, Claviez A, Heidorn K, Krupp G, Parwaresch R, Harms D, Rudolph P. Regulation of telomerase activity by alternate splicing of human telomerase reverse transcriptase mRNA in a subset of neuroblastomas. THE AMERICAN JOURNAL OF PATHOLOGY 2001; 159:1925-32. [PMID: 11696453 PMCID: PMC1867056 DOI: 10.1016/s0002-9440(10)63039-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
It has been proposed that the regulation of telomerase takes place at the transcriptional level, the expression of the catalytic subunit human telomerase reverse transcriptase (hTERT) being crucial for telomerase activity (TA). Recently, differential splicing of hTERT mRNA has been demonstrated in various tissues during embryonal development, and it has been suggested that only full-length transcripts translate into functionally active telomerase. With this in view, we analyzed the different hTERT transcripts by reverse transcriptase-polymerase chain reaction in neuroblastic tumors and compared the results with the TA, the tumor growth fraction, and the MYCN status. In a series of 38 neuroblastic tumors, high TA and full-length hTERT transcripts were found in nine samples, whereas nine samples showed absence of both enzymatic activity and hTERT transcripts. Interestingly, in another eight samples, low or absent TA coincided with a lack of full-length hTERT transcripts. Eleven samples contained hTERT transcripts with low or undetectable TA and one sample had low TA but no hTERT transcripts. TA correlated with MYCN amplification and was weakly associated with the proliferative activity. Moreover, a significant correlation with tumor progression was observed. Our findings point at a posttranscriptional regulation of TA in a subset of neuroblastic tumors. Because high TA was detected only in tumors with full-length hTERT transcripts, reverse transcriptase-polymerase chain reaction analysis of archival neuroblastic tumor samples might help to appraise the malignant potential in individual cases.
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Affiliation(s)
- M Krams
- Department of Pathology, University of Kiel, Kiel, Germany.
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29
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Paradis V, Bièche I, Dargère D, Bonvoust F, Ferlicot S, Olivi M, Lagha NB, Blanchet P, Benoît G, Vidaud M, Bedossa P. hTERT expression in sporadic renal cell carcinomas. J Pathol 2001; 195:209-17. [PMID: 11592100 DOI: 10.1002/path.917] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Human telomerase is a specialized reverse transcriptase that catalyses telomeric repeat addition at the ends of chromosomes. Activation of this enzyme is one of the key steps in cell immortalization and carcinogenesis, and one of its components, hTERT, is considered as the rate-limiting factor. While telomerase activity was found to be prognostically relevant in various cancers, results obtained from renal cell carcinomas (RCC) failed to show any correlation with the usual prognostic factors. The aim of the study was to reassess the role of telomerase and its hTERT component in the biological behaviour of RCC using new quantitative techniques, such as the quantitative evaluation of hTERT mRNA level by a real-time RT-PCR procedure and the measuring of telomerase activity by an ELISA TRAP assay. Since experimental evidence supports a relationship between cell proliferation or c-myc expression and telomerase, the proliferation index and c-myc mRNA levels were also studied. Forty-one RCC (29 conventional renal cell carcinomas (CRCC), 10 papillary RCC and two urothelial carcinomas) were studied. In 73% of cases, normalized hTERT mRNA expression was significantly higher in the tumour sample than in the normal tissue. Telomerase activity was detected in 63% of RCC, while corresponding normal tissue was always negative. Analysis of correlations showed firstly that both telomerase activity and hTERT mRNA level were lower in the group of CRCC versus non-CRCC (TRAP: 0.3+/-0.1 versus 0.6+/-0.2, p<0.05; hTERT/PO mRNA: 5+/-3 versus 37+/-8, p<0.001, respectively); secondly, that in the group of CRCC, hTERT mRNA expression level was correlated with the stage of the tumour (p=0.01); and thirdly, that no correlation was observed between c-myc mRNA level and hTERT mRNA level. In conclusion, these results support the involvement of telomerase in RCC and the potential interest of hTERT mRNA quantification.
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Affiliation(s)
- V Paradis
- Service d'Anatomie Pathologique, Hôpital de Bicêtre, Le Kremlin-Bicêtre, UPRES EA 1602, Faculté de Médecine, Paris-sud, France.
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30
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Abstract
Telomerase, the ribonucleoprotein enzyme that elongates chromosomal ends, or telomeres, is repressed in most normal somatic cells but reactivated in transformed cells to compensate for the progressive erosion of the telomeres during cell divisions. In accordance with this hypothesis, the presence of telomerase activity has been reported in more than 90% of human cancers, whereas most normal tissues or benign tumors contain low or undetectable telomerase activity. Reactivation of telomerase has also been widely reported in endocrine neoplasms and in hormone-related cancers. In the present study, we review the most recent publications on telomerase in these types of tumors. The hormonal regulation of telomerase activity and the possible strategies for cancer therapy based on the inhibition of telomerase has also been discussed.
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Affiliation(s)
- C Orlando
- Clinical Biochemistry Unit, Department of Clinical Physiopathology, University of Florence, viale Pieraccini 6, 50139, Florence, Italy.
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31
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Elenitoba-Johnson KS. Complex regulation of telomerase activity: implications for cancer therapy. THE AMERICAN JOURNAL OF PATHOLOGY 2001; 159:405-10. [PMID: 11485897 PMCID: PMC1850547 DOI: 10.1016/s0002-9440(10)61710-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- K S Elenitoba-Johnson
- Department of Pathology, University of Utah School of Medicine, 50 North Medical Drive, Salt Lake City, UT 84132, USA.
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32
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Landberg G, Ostlund H, Nielsen NH, Roos G, Emdin S, Burger AM, Seth A. Downregulation of the potential suppressor gene IGFBP-rP1 in human breast cancer is associated with inactivation of the retinoblastoma protein, cyclin E overexpression and increased proliferation in estrogen receptor negative tumors. Oncogene 2001; 20:3497-505. [PMID: 11429696 DOI: 10.1038/sj.onc.1204471] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2001] [Revised: 03/01/2001] [Accepted: 03/15/2001] [Indexed: 12/31/2022]
Abstract
The complex insulin-like growth factor network of ligands, receptors and binding proteins has been shown to be disturbed in breast cancer. In addition to defects in proteins controlling cell cycle checkpoints, this type of aberrations could affect tumor growth and survival thereby influencing both tumor aggressiveness and potential response to treatments. We have previously identified the T1A12/mac25 protein, which is identical to the IGFBP-rP1, as a differentially expressed gene product in breast cancer cells compared with normal cells. Here we compare the expression of IGFBP-rP1 in 106 tumor samples with known status of cell cycle aberrations and other clinicopathological data. This was done using a tumor tissue section array system that allows for simultaneous immunohistochemical staining of all samples in parallel. Cytoplasmic staining of variable intensity was observed in most tumors, 15% lacked IGFBP-rP1 staining completely, 20% had weak staining, 32% intermediate and 33% showed strong staining. Low IGFBP-rP1 was associated with high cyclin E protein content, retinoblastoma protein (pRb) inactivation, low bcl-2 protein, poorly differentiated tumors and higher stage. There was a significantly impaired prognosis for patients with low IGFBP-rP1 protein tumors. Interestingly, IGFBP-rP1 showed an inverse association with proliferation (Ki-67%) in estrogen receptor negative tumors as well as in cyclin E high tumors suggesting a separate cell cycle regulatory function for IGFBP-rP1 independent of interaction with the estrogen receptor or the pRb pathway.
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MESH Headings
- Aneuploidy
- Biomarkers, Tumor/analysis
- Biomarkers, Tumor/genetics
- Breast Neoplasms/genetics
- Breast Neoplasms/pathology
- Carrier Proteins/analysis
- Carrier Proteins/genetics
- Cell Cycle/genetics
- Cell Cycle/physiology
- Cyclin D1/analysis
- Cyclin E/analysis
- Diploidy
- Female
- Gene Expression Regulation, Neoplastic
- Genes, Tumor Suppressor
- Genes, bcl-2
- Genes, erbB-2
- Genes, p53
- Humans
- Immunohistochemistry
- Insulin-Like Growth Factor Binding Proteins
- Lymphatic Metastasis
- Menopause
- Neoplasm Invasiveness
- Neoplasm Staging
- Polymorphism, Single-Stranded Conformational
- Prognosis
- Receptors, Estrogen/analysis
- Receptors, Progesterone/analysis
- Retinoblastoma Protein/metabolism
- Telomerase/analysis
- Tumor Suppressor Protein p53/analysis
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Affiliation(s)
- G Landberg
- Division of Pathology, Department of Laboratory Medicine, Lund University, Malmö University Hospital, Malmö, Sweden
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33
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Bonatz G, Frahm SO, Klapper W, Helfenstein A, Heidorn K, Jonat W, Krupp G, Parwaresch R, Rudolph P. High telomerase activity is associated with cell cycle deregulation and rapid progression in endometrioid adenocarcinoma of the uterus. Hum Pathol 2001; 32:605-14. [PMID: 11431715 DOI: 10.1053/hupa.2001.25002] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Telomerase activity, a mechanism granting cellular immortality, has been detected in most cancer entities, but its association with clinical, histopathologic, and prognostic parameters is not fully understood. We investigated whether quantitative telomerase levels are correlated to established prognostic factors, telomere lengths, cell cycle kinetics, and the clinical course in endometrioid adenocarcinoma of the uterus (EC). A modified telomeric repeat amplification protocol (TRAP) was used to quantify the relative telomerase activity in a series of 53 primary tumors. Mean telomere length was determined by Southern blot analysis. Cell cycle kinetics were studied immunohistochemically on paraffin sections using monoclonal antibodies to 2 distinct proliferation-specific proteins: Ki-67, which is expressed throughout the cell cycle, and a novel cell cycle-associated protein, repp86, the expression of which is restricted to the cell cycle phases S, G2, and M. The ratio of the 2 immunolabeling indices defines the rate of transition through the restriction point. Telomerase activity was detected in 50 of 53 ECs (94%). Its levels correlated significantly with FIGO stage (P =.01) and FIGO grade (P =.003) but not with myometrial invasion. They were weakly associated with the overall proliferative activity (Ki-67, r =.48) but significantly with the repp86 index (r =.64) and even more strongly with the repp86:Ki-67 ratio (r =.77). There was no correlation with mean telomere length. In the group of tumors with high telomerase activity, 5 patients had relapses and 2 died of the disease within a median follow-up period of 29 months. Recurrence showed no relation to FIGO grade and stage. No events were observed in the group with low telomerase activity. In a multivariate model including tumor stage, histopathologic grade, depth of myometrial invasion, and Ki-67 indices, telomerase activity emerged as the only independent predictor of disease progression (P =.0002). It is concluded that beyond a link to proliferation, high telomerase activity reflects a deregulation of the cell cycle associated with an increased rate of cells entering S phase and a higher degree of malignancy. Therefore, quantitative analysis of telomerase activity may be useful for identifying EC patients at high risk for recurrence.
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Affiliation(s)
- G Bonatz
- Department of Gynecology and Obstetrics, and Department of Pathology and Hematopathology, University of Kiel, Kiel, Germany
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34
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Stampfer MR, Yaswen P. Immortal transformation and telomerase reactivation of human mammary epithelial cells in culture. TELOMERASE, AGING AND DISEASE 2001. [DOI: 10.1016/s1566-3124(01)08006-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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35
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Vietor M, Winter S, Groscurth P, Naumann U, Weller M. On the significance of telomerase activity in human malignant glioma cells. Eur J Pharmacol 2000; 407:27-37. [PMID: 11050287 DOI: 10.1016/s0014-2999(00)00726-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Telomerase is critical for tumor cell immortalization and is a novel target for cancer chemotherapy. Here, we examined whether telomerase is expressed in glioma cell lines, whether telomerase activity is regulated by bcl-2 or p53, and whether telomerase activity predicts response to chemotherapy. Further, we characterized the effects of a candidate telomerase inhibitor, penclomedine, in glioma cells. All 12 human malignant glioma cell lines examined were telomerase positive. Telomerase activity was not modulated during cell cycle progression, did not correlate with p53 status or bcl-2 family protein expression, and did not predict drug sensitivity, except for an association with resistance to carmustine. Ectopic bcl-2 expression did not enhance telomerase activity. Wild-type p53 reduced telomerase activity in cell lines retaining p53 activity but not in p53-mutant cell lines. Penclomedine killed glioma cells via an apoptotic, but death receptor-, bcl-2- and caspase-independent pathway, but did not inhibit telomerase and did not act synergistically with cytotoxic drugs. We conclude that telomerase activity does not account for the differential chemosensitivity of human glioma cells and that penclomedine kills glioma cells via a telomerase-independent pathway.
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Affiliation(s)
- M Vietor
- Laboratory of Molecular Neuro-Oncology, Department of Neurology, University of Tübingen, School of Medicine, Hoppe-Seyler-Strasse 3, D-72076, Tübingen, Germany
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36
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Xu D, Wang Q, Gruber A, Björkholm M, Chen Z, Zaid A, Selivanova G, Peterson C, Wiman KG, Pisa P. Downregulation of telomerase reverse transcriptase mRNA expression by wild type p53 in human tumor cells. Oncogene 2000; 19:5123-33. [PMID: 11064449 DOI: 10.1038/sj.onc.1203890] [Citation(s) in RCA: 181] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The p53 tumor suppressor protein inhibits the formation of tumors through induction of cell cycle arrest and/or apoptosis. In the present study we demonstrated that p53 is also a powerful inhibitor of human telomerase reverse transcriptase (hTERT), a key component for telomerase. Activation of either exogenous temperature-sensitive (ts) p53 in BL41 Burkitt lymphoma cells or endogenous wild type (wt) p53 at a physiological level in MCF-7 breast carcinoma cells triggered a rapid downregulation of hTERT mRNA expression, independently of the induction of the p53 target gene p21. Co-transfection of an hTERT promoter construct with wt p53 but not mutant p53 in HeLa cells inhibited the hTERT promoter activity. Furthermore, the activation of the hTERT promoter in Drosophila Schneider SL2 cells was completely dependent on the ectopic expression of Sp1 and was abrogated by wt p53. Finally, wt p53 inhibited Sp1 binding to the hTERT proximal promoter by forming a p53-Sp1 complex. Since activation of telomerase, widely observed in human tumor cell lines and primary tumors, is a critical step in tumorigenesis, wt p53-triggered inhibition of hTERT/telomerase expression may reflect yet another mechanism of p53-mediated tumor suppression. Our findings provide new insights into both the biological function of p53 and the regulation of hTERT/telomerase expression.
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Affiliation(s)
- D Xu
- Department of Medicine, Division of Hematology, Radiumhemmet, Karolinska Hospital, SE-171 76 Stockholm, Sweden
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37
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Abstract
Human pre-malignant breast diseases, particularly ductal carcinoma in situ (DCIS) already display several of the aberrant phenotypes found in primary breast cancers, including chromosomal abnormalities, telomerase activity, inactivation of the p53 gene, and overexpression of some oncogenes. Efforts to model early breast carcinogenesis in human cell cultures have largely involved studies of in vitro transformation of normal finite lifespan human mammary epithelial cells (HMEC) to immortality and malignancy. We present a model of HMEC immortal transformation consistent with the known in vivo data. This model includes a recently described, presumably epigenetic process, termed conversion, which occurs in cells that have overcome stringent replicative senescence and are thus able to maintain proliferation with critically short telomeres. The conversion process involves reactivation of telomerase activity, and acquisition of good uniform growth in the absence and presence of TGFbeta. We propose that overcoming the proliferative constraints set by senescence, and undergoing conversion, represent key rate-limiting steps in human breast carcinogenesis, and occur during early stage breast cancer progression.
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Affiliation(s)
- M R Stampfer
- Lawrence Berkeley National Laboratory, University of California, Life Sciences Division, Berkeley 94720, USA.
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38
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Affiliation(s)
- K Mokbel
- St Bartholomew's Hospital, London, UK
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39
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Lam KY, Lo CY, Fan ST, Luk JM. Telomerase activity in pancreatic endocrine tumours: a potential marker for malignancy. Mol Pathol 2000; 53:133-6. [PMID: 10897332 PMCID: PMC1186919 DOI: 10.1136/mp.53.3.133] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/21/2000] [Indexed: 11/04/2022]
Abstract
AIMS Telomerase activation is known to be a common event in human cancer and may be a useful marker for malignancy. In general, the histological features of pancreatic endocrine tumours cannot be used to determine their malignant potential. The aim of this study was to investigate the role of testing telomerase activity in pancreatic endocrine tumours. METHODS Prospectively collected fresh frozen tissue specimens from 10 patients with pancreatic endocrine tumours (nine insulinomas, one adrenocorticotrophin producing pancreatic endocrine tumour) were examined by a highly sensitive polymerase chain reaction (PCR) based telomerase repeat protocol (TRAP). RESULTS Of the 10 pancreatic endocrine tumours, three had telomerase activity. The positive cases included two frankly malignant tumours with liver metastases and one pancreatic endocrine tumour occurring in the setting of multiple endocrine neoplasia type 1. The latter had an infiltrative border. Vascular and perineural tumour infiltration was noted. In the two malignant pancreatic endocrine tumours with liver metastases, telomerase activity was noted in the tumour and the adjacent morphologically non-neoplastic pancreas. CONCLUSION To our knowledge, this is the first report of the role of telomerase activity in pancreatic endocrine tumours. Telomerase activity might be useful for distinguishing between benign and malignant pancreatic endocrine tumours.
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Affiliation(s)
- K Y Lam
- Department of Pathology, University of Hong Kong Medical Center, Queen Mary Hospital, Hong Kong, SAR.
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40
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Mokbel KM, Parris CN, Ghilchik M, Amerasinghe CN, Newbold RF. Telomerase activity and lymphovascular invasion in breast cancer. EUROPEAN JOURNAL OF SURGICAL ONCOLOGY 2000; 26:30-3. [PMID: 10718176 DOI: 10.1053/ejso.1999.0736] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
BACKGROUND Telomerase is a ribonucleoprotein enzyme that plays an important role in cell immortalization and carcinogenesis. Lymphovascular invasion (LVI) is a fundamental step in the process of breast cancer metastasis and is recognized as an important prognostic factor in patients with breast cancer. METHODS Using a PCR-based assay, telomerase activity was determined in 34 prospectively collected infiltrating breast carcinomas. Adjacent sections of the specimens were examined histologically by two experienced breast pathologists using light microscopy and haematoxylin & eosin staining. RESULTS Telomerase activity was detected in 24 (71%) of 34 breast tumours. Two (20%) of 10 telomerase-negative tumours had LVI compared with 14 (58.3%) of 24 telomerase-positive tumours. This association was statistically significant (P<0.05). Telomerase activity was also significantly associated with nodal metastases but not with tumour grade, tumour size or menopausal status. CONCLUSIONS Telomerase reactivation is significantly associated with LVI in breast cancer and may reflect the metastatic potential of the disease.
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Affiliation(s)
- K M Mokbel
- Breast Unit, St Bartholomew's Hospital, London, UK.
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41
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Li H, Cao Y, Berndt MC, Funder JW, Liu JP. Molecular interactions between telomerase and the tumor suppressor protein p53 in vitro. Oncogene 1999; 18:6785-94. [PMID: 10597287 DOI: 10.1038/sj.onc.1203061] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The telomere DNA polymerase (telomerase) and the tumor suppressor protein p53 are frequently associated with human cancers, and activation of telomerase and inactivation of p53 involved in cancer cell immortalization. In this report, we demonstrate a direct interaction of telomerase with p53 in the nuclear lysates of human breast cancer cells, and with recombinant human p53, by affinity chromatography and immunoprecipitation. On activity criteria, the interaction is between the carboxyl-terminal region of p53 and a region close to the amino-terminus of human telomerase-associated protein 1 (hTEP1). Incubation of recombinant p53 with nuclear telomerase extracts results in inhibition of telomerase activity, with the C-terminal region of p53 being essential for inhibition. This effect is not mediated by binding to telomerase substrate DNA, but requires the region near the N-terminus of hTEP1, in that a synthetic peptide derived from this region of hTEP1 similarly inhibits telomerase activity. Together, these in vitro interactions between telomerase and p53 suggest that the activity of telomerase may be regulated by p53, down-regulation of which in turn would favor up-regulation of telomerase activity in cancer cell development.
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Affiliation(s)
- H Li
- Molecular Signaling Laboratory, Baker Medical Research Institute, Prahran, Victoria, Australia
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Swisshelm K. Concepts of immortalization in human mammary epithelial cells. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 1999; 24:155-72. [PMID: 10547862 DOI: 10.1007/978-3-662-06227-2_7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Affiliation(s)
- K Swisshelm
- Department of Pathology, University of Washington, Seattle 98195-7470, USA
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Falchetti A, Becherini L, Martineti V, Morelli A, Benvenuti S, Picariello L, Gennari L, Lampugnani R, Bordi C, Brandi ML. Telomerase repeat amplification protocol (TRAP): A new molecular marker for parathyroid carcinoma. Biochem Biophys Res Commun 1999; 265:252-5. [PMID: 10548522 DOI: 10.1006/bbrc.1999.1320] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Telomerase results to be active in human germ, stem cells, several malignant cell tumors and in immortalized cell lines. In order to investigate if molecular mechanisms other than Rb gene inactivation can be helpful to diagnose malignancy of parathyroid tumors, we decided to investigate the presence of active telomerase in homogenates from different pathological parathyroid tissues (hyperplastic, adenomatous, carcinomatous, and normal) and primary cell cultures. The TRAP assay was performed to detect this activity in histologically characterized normal, hyperplastic, adenomatous, and carcinomatous human parathyroid tissues, primary cell lines, and one metastatic tissue from parathyroid carcinoma. Only malignant parathyroid glands and the metastatic tissue were TRAP positive. Our findings suggest that telomerase expression could represent an important molecular mechanism underlying the acquisition and progression of an aggressive phenotype of epithelial parathyroid cells and it may help to predict their malignant potential. The TRAP assay is easy to perform and it could become an additional tool to be included in the harmamentarium for the molecular diagnosis of parathyroid carcinoma.
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Affiliation(s)
- A Falchetti
- Department of Clinical Physiopathology, University of Florence, Florence, Italy
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44
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Abstract
Telomerase, the enzyme responsible for maintenance of the telomeres, is absent from the vast majority of somatic cells but is present in most tumours. Little is known about how telomerase is activated in cancer, although it is thought vital for immortalisation to occur. The aim of our study was to identify genetic changes associated with telomerase activity. Thirty-three breast carcinomas were assessed for telomerase activity using the PCR based TRAP assay, and genetic changes by comparative genomic hybridisation (CGH). Seventy-five percent of the tumours were telomerase positive, and these were further divided into low or high level telomerase activity groups. A large number of genetic aberrations were identified but 4 chromosomal regions were identified that correlated with the telomerase status of the tumour. Gain of 1q correlated with telomerase negative tumours, gain of 3q correlated with high level telomerase activity. Gain of 8q correlated with telomerase positive tumours and furthermore with high level telomerase activity; deletion of 17p also correlated with high level telomerase activity. CGH analysis of breast tumours in conjunction with telomerase status has supported early results suggesting the involvement of the telomerase hTR, c-myc and p53 genes in the control of telomerase activity. These genes are located on chromosomes 3q, 8q and 17p. Most importantly, our results have identified the involvement of gene(s) located on chromosome 1q in telomerase expression.
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Affiliation(s)
- R L Loveday
- Academic Surgical Unit, Castle Hill Hospital, Hull, UK
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45
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Mokbel K, Parris CN, Ghilchik M, Williams G, Newbold RF. The association between telomerase, histopathological parameters, and KI-67 expression in breast cancer. Am J Surg 1999; 178:69-72. [PMID: 10456708 DOI: 10.1016/s0002-9610(99)00128-2] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Telomerase is a ribonucleoprotein enzyme that appears to play an important role in carcinogenesis. Telomerase reactivation seems to be associated with immortalization and malignancy. METHODS Using a polymerase chain reaction (PCR)-based assay known as the TRAP (telomeric repeat and amplification protocol) assay, we examined telomerase activity in 60 breast specimens prospectively collected from 39 patients undergoing elective breast surgery in our center. The specimens included adjacent noncancerous breast (n = 21), benign breast disease (n = 5), and infiltrating carcinoma (n = 34). Ki-67 expression was determined in 32 invasive breast cancer specimens using immunohistochemistry techniques. The histopathological features were determined by light microscopy by an experienced breast pathologist. RESULTS Telomerase activity was detected in 24 (71%) of 34 infiltrating carcinomas. None of the adjacent noncancerous specimens nor the benign breast lesions expressed telomerase activity. Telomerase reactivation was significantly associated with nodal metastasis and Ki-67 expression. There was no significant association between telomerase activity and menopausal status, tumor grade, or tumor size. CONCLUSIONS Telomerase reactivation is associated with the acquisition of malignancy in the human breast. Telomerase activity is significantly associated with nodal metastasis and cellular proliferation as measured by Ki-67 expression in human breast cancer.
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