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Gao X, Lai Y, Luo X, Peng D, Li Q, Zhou H, Xue Y, Guo H, Zhao J, Yang H, Kuang S, Wang Z, Zhang M, Deng C, Wu S, Rao F. Acetyltransferase p300 regulates atrial fibroblast senescence and age-related atrial fibrosis through p53/Smad3 axis. Aging Cell 2022; 22:e13743. [PMID: 36468256 PMCID: PMC9835568 DOI: 10.1111/acel.13743] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 09/30/2022] [Accepted: 11/06/2022] [Indexed: 12/09/2022] Open
Abstract
Atrial fibrosis induced by aging is one of the main causes of atrial fibrillation (AF), but the potential molecular mechanism is not clear. Acetyltransferase p300 participates in the cellular senescence and fibrosis, which might be involved in the age-related atrial fibrosis. Four microarray datasets generated from atrial tissue of AF patients and sinus rhythm (SR) controls were analyzed to find the possible relationship of p300 (EP300) with senescence and fibrosis. And then, biochemical assays and in vivo electrophysiological examination were performed on older AF patients, aging mice, and senescent atrial fibroblasts. The results showed that (1) the left atrial tissues of older AF patients, aging mouse, and senescence human atrial fibroblasts had more severe atrial fibrosis and higher protein expression levels of p300, p53/acetylated p53 (ac-p53)/p21, Smad3/p-Smads, and fibrosis-related factors. (2) p300 inhibitor curcumin and p300 knockdown treated aging mouse and senescence human atrial fibroblasts reduced the senescence ratio of atrial fibroblasts, ameliorated the atrial fibrosis, and decreased the AF inducibility. In contrast, over-expression of p300 can lead to the senescence of atrial fibroblasts and atrial fibrosis. (3) p53 knockdown decreased the expression of aging and fibrosis-related proteins. (4) Co-immunoprecipitation and immunofluorescence showed that p53 forms a complex with smad3 and directly regulates the expression of smad3 in atrial fibroblasts. Our findings suggest that the mechanism of atrial fibrosis induced by aging is, at least, partially dependent on the regulation of p300, which provides new sights into the AF treatment, especially for the elderly.
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Affiliation(s)
- Xiao‐Yan Gao
- Guangdong Cardiovascular Institute, Guangdong Provincial People's HospitalGuangdong Academy of Medical SciencesGuangzhouChina,Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's HospitalGuangdong Academy of Medical SciencesGuangzhouChina
| | - Ying‐Yu Lai
- Guangdong Cardiovascular Institute, Guangdong Provincial People's HospitalGuangdong Academy of Medical SciencesGuangzhouChina,Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's HospitalGuangdong Academy of Medical SciencesGuangzhouChina,Department of PharmacyThe People's Hospital of HezhouHezhouChina
| | - Xue‐Shan Luo
- Guangdong Cardiovascular Institute, Guangdong Provincial People's HospitalGuangdong Academy of Medical SciencesGuangzhouChina,Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's HospitalGuangdong Academy of Medical SciencesGuangzhouChina
| | - De‐Wei Peng
- Guangdong Cardiovascular Institute, Guangdong Provincial People's HospitalGuangdong Academy of Medical SciencesGuangzhouChina,Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's HospitalGuangdong Academy of Medical SciencesGuangzhouChina
| | - Qiao‐Qiao Li
- Guangdong Cardiovascular Institute, Guangdong Provincial People's HospitalGuangdong Academy of Medical SciencesGuangzhouChina,Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's HospitalGuangdong Academy of Medical SciencesGuangzhouChina
| | - Hui‐Shan Zhou
- Guangdong Cardiovascular Institute, Guangdong Provincial People's HospitalGuangdong Academy of Medical SciencesGuangzhouChina,Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's HospitalGuangdong Academy of Medical SciencesGuangzhouChina
| | - Yu‐Mei Xue
- Guangdong Cardiovascular Institute, Guangdong Provincial People's HospitalGuangdong Academy of Medical SciencesGuangzhouChina,Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's HospitalGuangdong Academy of Medical SciencesGuangzhouChina
| | - Hui‐Ming Guo
- Guangdong Cardiovascular Institute, Guangdong Provincial People's HospitalGuangdong Academy of Medical SciencesGuangzhouChina
| | - Jun‐Fei Zhao
- Guangdong Cardiovascular Institute, Guangdong Provincial People's HospitalGuangdong Academy of Medical SciencesGuangzhouChina
| | - Hui Yang
- Guangdong Cardiovascular Institute, Guangdong Provincial People's HospitalGuangdong Academy of Medical SciencesGuangzhouChina,Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's HospitalGuangdong Academy of Medical SciencesGuangzhouChina
| | - Su‐Juan Kuang
- Guangdong Cardiovascular Institute, Guangdong Provincial People's HospitalGuangdong Academy of Medical SciencesGuangzhouChina,Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's HospitalGuangdong Academy of Medical SciencesGuangzhouChina
| | - Zhao‐Yu Wang
- Guangdong Cardiovascular Institute, Guangdong Provincial People's HospitalGuangdong Academy of Medical SciencesGuangzhouChina,Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's HospitalGuangdong Academy of Medical SciencesGuangzhouChina
| | - Meng‐Zhen Zhang
- Guangdong Cardiovascular Institute, Guangdong Provincial People's HospitalGuangdong Academy of Medical SciencesGuangzhouChina,Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's HospitalGuangdong Academy of Medical SciencesGuangzhouChina
| | - Chun‐Yu Deng
- Guangdong Cardiovascular Institute, Guangdong Provincial People's HospitalGuangdong Academy of Medical SciencesGuangzhouChina,Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's HospitalGuangdong Academy of Medical SciencesGuangzhouChina
| | - Shu‐Lin Wu
- Guangdong Cardiovascular Institute, Guangdong Provincial People's HospitalGuangdong Academy of Medical SciencesGuangzhouChina,Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's HospitalGuangdong Academy of Medical SciencesGuangzhouChina
| | - Fang Rao
- Guangdong Cardiovascular Institute, Guangdong Provincial People's HospitalGuangdong Academy of Medical SciencesGuangzhouChina,Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's HospitalGuangdong Academy of Medical SciencesGuangzhouChina
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Suppression of Ribose-5-Phosphate Isomerase a Induces ROS to Activate Autophagy, Apoptosis, and Cellular Senescence in Lung Cancer. Int J Mol Sci 2022; 23:ijms23147883. [PMID: 35887232 PMCID: PMC9322731 DOI: 10.3390/ijms23147883] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 07/14/2022] [Accepted: 07/15/2022] [Indexed: 02/04/2023] Open
Abstract
Ribose-5-phosphate isomerase A (RPIA) regulates tumorigenesis in liver and colorectal cancer. However, the role of RPIA in lung cancer remains obscure. Here we report that the suppression of RPIA diminishes cellular proliferation and activates autophagy, apoptosis, and cellular senescence in lung cancer cells. First, we detected that RPIA protein was increased in the human lung cancer versus adjust normal tissue via tissue array. Next, the knockdown of RPIA in lung cancer cells displayed autophagic vacuoles, enhanced acridine orange staining, GFP-LC3 punctae, accumulated autophagosomes, and showed elevated levels of LC3-II and reduced levels of p62, together suggesting that the suppression of RPIA stimulates autophagy in lung cancer cells. In addition, decreased RPIA expression induced apoptosis by increasing levels of Bax, cleaved PARP and caspase-3 and apoptotic cells. Moreover, RPIA knockdown triggered cellular senescence and increased p53 and p21 levels in lung cancer cells. Importantly, RPIA knockdown elevated reactive oxygen species (ROS) levels. Treatment of ROS scavenger N-acetyl-L-cysteine (NAC) reverts the activation of autophagy, apoptosis and cellular senescence by RPIA knockdown in lung cancer cells. In conclusion, RPIA knockdown induces ROS levels to activate autophagy, apoptosis, and cellular senescence in lung cancer cells. Our study sheds new light on RPIA suppression in lung cancer therapy.
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Sossey-Alaoui K, Pluskota E, Szpak D, Plow EF. The Kindlin2-p53-SerpinB2 signaling axis is required for cellular senescence in breast cancer. Cell Death Dis 2019; 10:539. [PMID: 31308359 PMCID: PMC6629707 DOI: 10.1038/s41419-019-1774-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 06/18/2019] [Accepted: 06/27/2019] [Indexed: 02/06/2023]
Abstract
In cancer, cellular senescence is a complex process that leads to inhibition of proliferation of cells that may develop a neoplastic phenotype. A plethora of signaling pathways, when dysregulated, have been shown to elicit a senescence response. Two well-known tumor suppressor pathways, controlled by the p53 and retinoblastoma proteins, have been implicated in maintaining the cellular senescence phenotype. Kindlin-2, a member of an actin cytoskeleton organizing and integrin activator proteins, has been shown to play a key role in the regulation of several hallmarks of several cancers, including breast cancer (BC). The molecular mechanisms whereby Kindlin-2 regulates cellular senescence in BC tumors remains largely unknown. Here we show that Kindlin-2 regulates cellular senescence in part through its interaction with p53, whereby it regulates the expression of the p53-responsive genes; i.e., SerpinB2 and p21, during the induction of senescence. Our data show that knockout of Kindlin-2 via CRISPR/Cas9 in several BC cell lines significantly increases expression levels of both SerpinB2 and p21 resulting in the activation of hallmarks of cellular senescence. Mechanistically, interaction between Kindlin-2 and p53 at the promotor level is critical for the regulated expression of SerpinB2 and p21. These findings identify a previously unknown Kindlin-2/p53/SerpinB2 signaling axis that regulates cellular senescence and intervention in this axis may serve as a new therapeutic window for BCs treatment.
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Affiliation(s)
- Khalid Sossey-Alaoui
- Department of Cardiovascular & Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA. .,Case Western Reserve University-MetroHealth Medical Research Center, Cleveland, OH, USA.
| | - Elzbieta Pluskota
- Department of Cardiovascular & Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Dorota Szpak
- Department of Cardiovascular & Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Edward F Plow
- Department of Cardiovascular & Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
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Jayesh P, Seena J, Singh ISB. Establishment of shrimp cell lines: perception and orientation. INDIAN JOURNAL OF VIROLOGY : AN OFFICIAL ORGAN OF INDIAN VIROLOGICAL SOCIETY 2012; 23:244-51. [PMID: 23997447 PMCID: PMC3550748 DOI: 10.1007/s13337-012-0089-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Accepted: 06/26/2012] [Indexed: 12/13/2022]
Abstract
Development of continuous shrimp cell lines for effective investigation on shrimp viruses remains elusive with an arduous history of over 25 years. Despite presenting challenges to researchers in developing a cell line, the billion dollar aquaculture industry is under viral threat. Advances in molecular biology and various gene transfer technologies for immortalization of cells have resulted in the development of hundreds of cell lines from insects and mammals, but yet not a single cell line has been developed from shrimp and other marine invertebrates. Though improved growth and longevity of shrimp cells in vitro could be achieved by using modified growth media this did not make any leap to spontaneous transformation; probably due to the fact that shrimp cells inhibited neoplastic transformations. Oncogenic induction and immortalization are considered as the possible ways, and an exclusive medium for shrimp cell culture and an appropriate mode of transformation are crucial. In this review status of shrimp cell line development and its future orientation are discussed.
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Affiliation(s)
- P. Jayesh
- National Centre for Aquatic Animal Health, Cochin University of Science and Technology, Lakeside Campus, Fine Arts Avenue, Cochin, 682016 India
| | - Jose Seena
- National Centre for Aquatic Animal Health, Cochin University of Science and Technology, Lakeside Campus, Fine Arts Avenue, Cochin, 682016 India
| | - I. S. Bright Singh
- National Centre for Aquatic Animal Health, Cochin University of Science and Technology, Lakeside Campus, Fine Arts Avenue, Cochin, 682016 India
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5
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Saha A, Lu J, Morizur L, Upadhyay SK, AJ MP, Robertson ES. E2F1 mediated apoptosis induced by the DNA damage response is blocked by EBV nuclear antigen 3C in lymphoblastoid cells. PLoS Pathog 2012; 8:e1002573. [PMID: 22438805 PMCID: PMC3305458 DOI: 10.1371/journal.ppat.1002573] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Accepted: 01/25/2012] [Indexed: 01/06/2023] Open
Abstract
EBV latent antigen EBNA3C is indispensible for in vitro B-cell immortalization resulting in continuously proliferating lymphoblastoid cell lines (LCLs). EBNA3C was previously shown to target pRb for ubiquitin-proteasome mediated degradation, which facilitates G1 to S transition controlled by the major transcriptional activator E2F1. E2F1 also plays a pivotal role in regulating DNA damage induced apoptosis through both p53-dependent and -independent pathways. In this study, we demonstrate that in response to DNA damage LCLs knocked down for EBNA3C undergo a drastic induction of apoptosis, as a possible consequence of both p53- and E2F1-mediated activities. Importantly, EBNA3C was previously shown to suppress p53-induced apoptosis. Now, we also show that EBNA3C efficiently blocks E2F1-mediated apoptosis, as well as its anti-proliferative effects in a p53-independent manner, in response to DNA damage. The N- and C-terminal domains of EBNA3C form a stable pRb independent complex with the N-terminal DNA-binding region of E2F1 responsible for inducing apoptosis. Mechanistically, we show that EBNA3C represses E2F1 transcriptional activity via blocking its DNA-binding activity at the responsive promoters of p73 and Apaf-1 apoptosis induced genes, and also facilitates E2F1 degradation in an ubiquitin-proteasome dependent fashion. Moreover, in response to DNA damage, E2F1 knockdown LCLs exhibited a significant reduction in apoptosis with higher cell-viability. In the presence of normal mitogenic stimuli the growth rate of LCLs knockdown for E2F1 was markedly impaired; indicating that E2F1 plays a dual role in EBV positive cells and that active engagement of the EBNA3C-E2F1 complex is crucial for inhibition of DNA damage induced E2F1-mediated apoptosis. This study offers novel insights into our current understanding of EBV biology and enhances the potential for development of effective therapies against EBV associated B-cell lymphomas. Aberrant cellular proliferation due to deregulation of E2F1 transcriptional activity as a result of either genetic or functional alterations of its upstream components is a hallmark of human cancer. Interestingly, E2F1 can also promote cellular apoptosis regardless of p53 status by activating a number of pro-apoptotic genes in response to DNA damage stimuli. Epstein-Barr virus (EBV) encoded essential latent antigen EBNA3C can suppress p53-mediated apoptotic activities. This study now demonstrates that EBNA3C can further impede E2F1 mediated apoptosis by inhibiting its transcriptional ability, as well as by facilitating its degradation in an ubiquitin-proteasome dependent manner. This is the first evidence, which shows through targeting EBNA3C function linked to the E2F1-mediated apoptotic pathway, an additional therapeutic platform could be implemented against EBV-associated human B-cell lymphomas.
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Affiliation(s)
- Abhik Saha
- Department of Microbiology and Tumor Virology Program of the Abramson Comprehensive Cancer Center, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Jie Lu
- Department of Microbiology and Tumor Virology Program of the Abramson Comprehensive Cancer Center, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Lise Morizur
- Department of Microbiology and Tumor Virology Program of the Abramson Comprehensive Cancer Center, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Santosh K. Upadhyay
- Department of Microbiology and Tumor Virology Program of the Abramson Comprehensive Cancer Center, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Mahadesh Prasad AJ
- Department of Microbiology and Tumor Virology Program of the Abramson Comprehensive Cancer Center, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Erle S. Robertson
- Department of Microbiology and Tumor Virology Program of the Abramson Comprehensive Cancer Center, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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6
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Watabe-Rudolph M, Begus-Nahrmann Y, Lechel A, Rolyan H, Scheithauer MO, Rettinger G, Thal DR, Rudolph KL. Telomere shortening impairs regeneration of the olfactory epithelium in response to injury but not under homeostatic conditions. PLoS One 2011; 6:e27801. [PMID: 22110763 PMCID: PMC3218037 DOI: 10.1371/journal.pone.0027801] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Accepted: 10/25/2011] [Indexed: 01/10/2023] Open
Abstract
Atrophy of the olfactory epithelium (OE) associated with impaired olfaction and dry nose represents one of the most common phenotypes of human aging. Impairment in regeneration of a functional olfactory epithelium can also occur in response to injury due to infection or nasal surgery. These complications occur more frequently in aged patients. Although age is the most unifying risk factor for atrophic changes and functional decline of the olfactory epithelium, little is known about molecular mechanisms that could influence maintenance and repair of the olfactory epithelium. Here, we analyzed the influence of telomere shortening (a basic mechanism of cellular aging) on homeostasis and regenerative reserve in response to chemical induced injury of the OE in late generation telomere knockout mice (G3 mTerc(-/-)) with short telomeres compared to wild type mice (mTerc(+/+)) with long telomeres. The study revealed no significant influence of telomere shortening on homeostatic maintenance of the OE during mouse aging. In contrast, the regenerative response to chemical induced injury of the OE was significantly impaired in G3 mTerc(-/-) mice compared to mTerc(+/+) mice. Seven days after chemical induced damage, G3 mTerc(-/-) mice exhibited significantly enlarged areas of persisting atrophy compared to mTerc(+/+) mice (p = 0.031). Telomere dysfunction was associated with impairments in cell proliferation in the regenerating epithelium. Deletion of the cell cycle inhibitor, Cdkn1a (p21) rescued defects in OE regeneration in telomere dysfunctional mice. Together, these data indicate that telomere shortening impairs the regenerative capacity of the OE by impairing cell cycle progression in a p21-dependent manner. These findings could be relevant for the impairment in OE function in elderly people.
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Affiliation(s)
| | - Yvonne Begus-Nahrmann
- Max-Planck-Research Department of Stem Cell Aging and Institute of Molecular Medicine, University of Ulm, Ulm, Germany
| | - André Lechel
- Max-Planck-Research Department of Stem Cell Aging and Institute of Molecular Medicine, University of Ulm, Ulm, Germany
| | - Harshvardhan Rolyan
- Max-Planck-Research Department of Stem Cell Aging and Institute of Molecular Medicine, University of Ulm, Ulm, Germany
| | | | | | | | - Karl Lenhard Rudolph
- Max-Planck-Research Department of Stem Cell Aging and Institute of Molecular Medicine, University of Ulm, Ulm, Germany
- * E-mail:
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Choi OR, Lim IK. Loss of p21(Sdi1) expression in senescent cells after DNA damage accompanied with increase of miR-93 expression and reduced p53 interaction with p21(Sdi1) gene promoter. Biochem Biophys Res Commun 2011; 407:406-11. [PMID: 21402054 DOI: 10.1016/j.bbrc.2011.03.038] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2011] [Accepted: 03/09/2011] [Indexed: 12/20/2022]
Abstract
To answer what is a critical event for higher incidence of tumor development in old than young individuals, primary culture of human diploid fibroblasts were employed and DNA damage was induced by doxorubicin or X-ray irradiation. Response to the damage was different between young and old cells; loss of p21(sdi1) expression in spite of p53(S¹⁵) activation in old cells along with [³H]thymidine and BrdU incorporation, but not in young cells. The phenomenon was confirmed by other tissue fibroblasts obtained from different donor ages. Induction of miR-93 expression and reduced p53 binding to p21 gene promoter account for loss of p21(sdi1) expression in senescent cells after DNA damage, suggesting a mechanism of in vivo carcinogenesis in aged tissue without repair arrest.
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Affiliation(s)
- Ok Ran Choi
- Department of Biochemistry and Molecular Biology, Ajou University School of Medicine, Suwon 443-721, Republic of Korea
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Jiang M, Min Y, Debusk L, Fernandez S, Strand DW, Hayward SW, Lin PC. Spontaneous immortalization of human dermal microvascular endothelial cells. World J Stem Cells 2010; 2:114-20. [PMID: 21607128 PMCID: PMC3097930 DOI: 10.4252/wjsc.v2.i5.114] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2010] [Revised: 09/22/2010] [Accepted: 09/29/2010] [Indexed: 02/06/2023] Open
Abstract
AIM To establish and characterize a spontaneously immortalized human dermal microvascular endothelial cell line, iHDME1. METHODS We developed a spontaneous immortalization method. This approach is based on the application of optimized culture media and culture conditions without addition of any exogenous oncogenes or carcinogens. Using this approach, we have successfully established a microvascular endothelial cell line, iHDME1, from primary human dermal microvascular endothelial cells. iHDME1 cells have been maintained in culture dishes for more than 50 passages over a period of 6 mo. Using a GFP expressing retrovirus, we generated a GFP-stable cell line (iHDME1-GFP). RESULTS iHDME1 retain endothelial morphology and uniformly express endothelial markers such as VEGF receptor 2 and VE-cadherin but not α-smooth muscle actin (α-SM-actin) and cytokeratin 18, markers for smooth muscle cells and epithelial cells respectively. These cells retain endothelial properties, migrate in response to VEGF stimulation and form 3-D vascular structures in Matrigel, similar to the parental cells. There is no significant difference in cell cycle profile between the parental cells and iHDME1 cells. Further analysis indicates enhanced stemness in iHDME1 cells compared to parental cells. iHDME1 cells display elevated expression of CD133 and hTERT. CONCLUSION iHDME1 cells will be a valuable source for studying angiogenesis.
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Affiliation(s)
- Ming Jiang
- Ming Jiang, Suzanne Fernandez, Douglas W Strand, Simon W Hayward, Department of Urologic Surgery, Vanderbilt University Medical Center, 1161 21st Avenue South, Nashville, TN 37232, United States
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Rubio R, García-Castro J, Gutiérrez-Aranda I, Paramio J, Santos M, Catalina P, Leone PE, Menendez P, Rodríguez R. Deficiency in p53 but not retinoblastoma induces the transformation of mesenchymal stem cells in vitro and initiates leiomyosarcoma in vivo. Cancer Res 2010; 70:4185-94. [PMID: 20442289 DOI: 10.1158/0008-5472.can-09-4640] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Sarcomas have been modeled in mice by the expression of specific fusion genes in mesenchymal stem cells (MSC), supporting the concept that MSCs might be the target initiating cell in sarcoma. In this study, we evaluated the potential oncogenic effects of p53 and/or retinoblastoma (Rb) deficiency in MSC transformation and sarcomagenesis. We derived wild-type, p53(-/-), Rb(-/-), and p53(-/-)Rb(-/-) MSC cultures and fully characterized their in vitro growth properties and in vivo tumorigenesis capabilities. In contrast with wild-type MSCs, Rb(-/-), p53(-/-), and p53(-/-)Rb(-/-) MSCs underwent in vitro transformation and showed severe alterations in culture homeostasis. More importantly, p53(-/-) and p53(-/-)Rb(-/-) MSCs, but not Rb(-/-) MSCs, were capable of tumor development in vivo after injection into immunodeficient mice. p53(-/-) or p53(-/-)Rb(-/-) MSCs originated leiomyosarcoma-like tumors, linking this type of smooth muscle sarcoma to p53 deficiency in fat tissue-derived MSCs. Sca1+ and Sca1 low/- cell populations isolated from ex vivo-established, transformed MSC lines from p53(-/-)Rb(-/-) tumors showed identical sarcomagenesis potential, with 100% tumor penetrance and identical latency, tumor weight, and histologic profile. Our findings define the differential roles of p53 and Rb in MSC transformation and offer proof-of-principle that MSCs could provide useful tools to dissect the sarcoma pathogenesis.
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Affiliation(s)
- Ruth Rubio
- Andalusian Stem Cell Bank, Centro de Investigación Biomédica, Consejería de Salud-Universidad de Granada, Granada, Spain
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Banga SS, Peng L, Dasgupta T, Palejwala V, Ozer HL. PHF10 is required for cell proliferation in normal and SV40-immortalized human fibroblast cells. Cytogenet Genome Res 2010; 126:227-42. [PMID: 20068294 PMCID: PMC3711003 DOI: 10.1159/000251960] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/16/2009] [Indexed: 01/28/2023] Open
Abstract
Normal human diploid fibroblasts have limited life span in culture and undergo replicative senescence after 50-60 population doublings. On the contrary, cancer cells typically divide indefinitely and are immortal. Expression of SV40 large T and small t antigens in human fibroblasts transiently extends their life span by 20-30 population doublings and facilitates immortalization. We have identified a rearrangement in chromosome 6 shared by SV40-transformed human fibroblasts. Rearrangements involving chromosome 6 are among the most frequent in human carcinogenesis. In this paper, we extend analysis of the 6q26-q27 region, a putative site for a growth suppressor gene designated SEN6 involved in immortalization of SV40-transformed cells. Detailed molecular characterization of the rearranged chromosomes (6q*, normal appearing; and 6q(t), translocated) in the SV40-immortalized cell line HALneo by isolating each of these 2 chromosomes in mouse/HAL somatic cell hybrids is presented. Analysis of these mouse/HAL somatic cell hybrids with polymorphic and nonpolymorphic markers revealed that the 6q* has undergone a chromosomal break in the MLLT4 gene (alias AF6). This result in conjunction with previous published observations leads us to conclude that SEN6 lies between MLLT4 and TBP at chromosomal region 6q27. Examination of different genes (MLLT4, DLL1, FAM120B, PHF10) located within this interval that are expressed in HS74 normal fibroblast cells reveals that overexpression of epitope-tagged truncated PHF10 cDNAs resulted in reduced cell proliferation in multiple cell lines. Paradoxically, down-regulation of PHF10 by RNAi also resulted in loss of cell proliferation in normal fibroblast cells, indicating PHF10 function is required for cell growth. Taken together, these observations suggest that decreased cell proliferation with epitope-tagged truncated PHF10 proteins may be due to dominant negative effects or due to unregulated expression of these mutant proteins. Hence we conclude that PHF10 is not SEN6 but is required for cell growth.
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Affiliation(s)
- S S Banga
- Department of Microbiology and Molecular Genetics, New Jersey Medical School-University Hospital Cancer Center, University of Medicine and Dentistry of New Jersey, Newark, NJ 07103, USA. banga @ umdnj.edu
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Abstract
It is still enigmatic under which circumstances cellular demise induces an immune response or rather remains immunologically silent. Moreover, the question remains open under which circumstances apoptotic, autophagic or necrotic cells are immunogenic or tolerogenic. Although apoptosis appears to be morphologically homogenous, recent evidence suggests that the pre-apoptotic surface-exposure of calreticulin may dictate the immune response to tumor cells that succumb to anticancer treatments. Moreover, the release of high-mobility group box 1 (HMGB1) during late apoptosis and secondary necrosis contributes to efficient antigen presentation and cytotoxic T-cell activation because HMGB1 can bind to Toll like receptor 4 on dendritic cells, thereby stimulating optimal antigen processing. Cell death accompanied by autophagy also may facilitate cross priming events. Apoptosis, necrosis and autophagy are closely intertwined processes. Often, cells manifest autophagy before they undergo apoptosis or necrosis, and apoptosis is generally followed by secondary necrosis. Whereas apoptosis and necrosis irreversibly lead to cell death, autophagy can clear cells from stress factors and thus facilitate cellular survival. We surmise that the response to cellular stress like chemotherapy or ionizing irradiation, dictates the immunological response to dying cells and that this immune response in turn determines the clinical outcome of anticancer therapies. The purpose of this review is to summarize recent insights into the immunogenicity of dying tumor cells as a function of the cell death modality.
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Khatami M. 'Yin and Yang' in inflammation: duality in innate immune cell function and tumorigenesis. Expert Opin Biol Ther 2008; 8:1461-72. [PMID: 18774915 DOI: 10.1517/14712598.8.10.1461] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
BACKGROUND The two stages of the acute inflammatory process are apoptosis ('Yin') and wound healing or resolution ('Yang'). Inflammation defends the host against unwanted elements. OBJECTIVE/METHODS To present a discussion of pleiotropic roles of innate immune cells possessing 'tumoricidal' and/or 'tumorigenic' properties in inflammation-induced dysfunction of the immune system and the genesis of chronic inflammatory diseases, hyperplasia, precancer/neoplasia or tumor and angiogenesis. RESULTS/CONCLUSIONS Loss of maintenance of the balance between apoptosis and wound healing and co-existence of death and growth factors in tissues could create 'immunological chaos' with accumulation of 'immune response mismatches'. Unresolved inflammation plays a role in the genesis of chronic inflammatory and autoimmune diseases and cancer. Identification of accumulated 'mismatched' death and growth factors during the developmental phases of immune dysfunction in target tissues or cancer microenvironment presents challenges and opportunities for future studies on diagnosis, prevention and therapy of these diseases.
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Affiliation(s)
- Mahin Khatami
- The National Cancer Institute, The National Institutes of Health, Technology Program Development, Office of Technology and Industrial Relations, Bethesda, MD 20892, USA.
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13
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Galea AM, Murray V. The anti-tumour agent, cisplatin, and its clinically ineffective isomer, transplatin, produce unique gene expression profiles in human cells. Cancer Inform 2008; 6:315-55. [PMID: 19259415 PMCID: PMC2623290 DOI: 10.4137/cin.s802] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Cisplatin is a DNA-damaging anti-cancer agent that is widely used to treat a range of tumour types. Despite its clinical success, cisplatin treatment is still associated with a number of dose-limiting toxic side effects. The purpose of this study was to clarify the molecular events that are important in the anti-tumour activity of cisplatin, using gene expression profiling techniques. Currently, our incomplete understanding of this drug's mechanism of action hinders the development of more efficient and less harmful cisplatin-based chemotherapeutics. In this study the effect of cisplatin on gene expression in human foreskin fibroblasts has been investigated using human 19K oligonucleotide microarrays. In addition its clinically inactive isomer, transplatin, was also tested. Dualfluor microarray experiments comparing treated and untreated cells were performed in quadruplicate. Cisplatin treatment was shown to significantly up- or down-regulate a consistent subset of genes. Many of these genes responded similarly to treatment with transplatin, the therapeutically inactive isomer of cisplatin. However, a smaller proportion of these transcripts underwent differential expression changes in response to the two isomers. Some of these genes may constitute part of the DNA damage response induced by cisplatin that is critical for its anti-tumour activity. Ultimately, the identification of gene expression responses unique to clinically active compounds, like cisplatin, could thus greatly benefit the design and development of improved chemotherapeutics.
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Affiliation(s)
- Anne M. Galea
- School of Biochemistry and Molecular Genetics, University of New South Wales, Sydney, NSW 2052, Australia
| | - Vincent Murray
- School of Biochemistry and Molecular Genetics, University of New South Wales, Sydney, NSW 2052, Australia
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14
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Vicencio JM, Galluzzi L, Tajeddine N, Ortiz C, Criollo A, Tasdemir E, Morselli E, Ben Younes A, Maiuri MC, Lavandero S, Kroemer G. Senescence, Apoptosis or Autophagy? Gerontology 2008; 54:92-9. [DOI: 10.1159/000129697] [Citation(s) in RCA: 187] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2008] [Accepted: 01/30/2008] [Indexed: 12/11/2022] Open
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15
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Characteristics of primary and immortalized fibroblast cells derived from the miniature and domestic pigs. BMC Cell Biol 2007; 8:20. [PMID: 17543094 PMCID: PMC1894962 DOI: 10.1186/1471-2121-8-20] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2006] [Accepted: 06/01/2007] [Indexed: 12/20/2022] Open
Abstract
Background The pig, Sus scrofa domestica includes both the miniature and commercial domestic breed. These animals have influenced the human life and economies and have been studied throughout history. Although the miniature breeds are more recent and have increasingly been used in a variety of biomedical studies, their cell lines have rarely been established. Therefore, we sought to establish primary and immortal cell lines derived from both the miniature and domestic pig to better enable insight into possible in vivo growth differences. Results The in vitro lifespan of primary domestic pig fibroblast (PF) and miniature pig fibroblast (MPF) cells using a standard 3T3 protocol was determined. Both of the primary PF and MPF cells were shown to have a two-step replicative senescence barrier. Primary MPF cells exhibited a relatively shorter lifespan and slower proliferation rate compared to those of primary PF cells. Beyond senescence barriers, lifespan-extended PF and MPF cells were eventually established and indicated spontaneous cellular immortalization. In contrast to the immortalized PF cells, immortal MPF cells showed a transformed phenotype and possessed more frequent chromosomal abnormalities and loss of p53 regulatory function. The lifespan of primary MPF and PF cells was extended by inactivation of the p53 function using transduction by SV40LT without any detectable senescent phenotype. Conclusion These results suggest that p53 signaling might be a major determinant for the replicative senescence in the MPF cells that have the shorter lifespan and slower growth rate compared to PF cells in vitro.
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16
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Freyer MW, Buscaglia R, Kaplan K, Cashman D, Hurley LH, Lewis EA. Biophysical studies of the c-MYC NHE III1 promoter: model quadruplex interactions with a cationic porphyrin. Biophys J 2006; 92:2007-15. [PMID: 17172304 PMCID: PMC1861781 DOI: 10.1529/biophysj.106.097246] [Citation(s) in RCA: 123] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Regulation of the structural equilibrium of G-quadruplex-forming sequences located in the promoter regions of oncogenes by the binding of small molecules has shown potential as a new avenue for cancer chemotherapy. In this study, microcalorimetry (isothermal titration calorimetry and differential scanning calorimetry), electronic spectroscopy (ultraviolet-visible and circular dichroism), and molecular modeling were used to probe the complex interactions between a cationic porphryin mesotetra (N-methyl-4-pyridyl) porphine (TMPyP4) and the c-MYC PU 27-mer quadruplex. The stoichiometry at saturation is 4:1 mol of TMPyP4/c-MYC PU 27-mer G-quadruplex as determined by isothermal titration calorimetry, circular dichroism, and ultraviolet-visible spectroscopy. The four independent TMPyP4 binding sites fall into one of two modes. The two binding modes are different with respect to affinity, enthalpy change, and entropy change for formation of the 1:1 and 2:1, or 3:1 and 4:1 complexes. Binding of TMPyP4, at or near physiologic ionic strength ([K(+)] = 0.13 M), is described by a "two-independent-sites model." The two highest-affinity sites exhibit a K(1) of 1.6 x 10(7) M(-1) and the two lowest-affinity sites exhibit a K(2) of 4.2 x 10(5) M(-1). Dissection of the free-energy change into the enthalpy- and entropy-change contributions for the two modes is consistent with both "intercalative" and "exterior" binding mechanisms. An additional complexity is that there may be as many as six possible conformational quadruplex isomers based on the sequence. Differential scanning calorimetry experiments demonstrated two distinct melting events (T(m)1 = 74.7 degrees C and T(m)2 = 91.2 degrees C) resulting from a mixture of at least two conformers for the c-MYC PU 27-mer in solution.
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Affiliation(s)
- Matthew W Freyer
- Department of Chemistry and Biochemistry, Northern Arizona University, Flagstaff, Arizona, USA
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17
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Abstract
Carcinoma of the uterine cervix, a leading cause of cancer death in women worldwide, is initiated by infection with high-risk types of human papillomaviruses (HPVs). This review summarizes laboratory studies over the past 20 years that have elucidated the major features of the HPV life cycle, identified the functions of the viral proteins, and clarified the consequences of HPV infection for their host cells. This information has allowed the development of various strategies to prevent or treat infections, including prophylactic vaccination with virus-like particles, therapeutic vaccination against viral proteins expressed in cancer cells, and antiviral approaches to inhibit virus replication, spread, or pathogenesis. These strategies have the potential to cause a dramatic reduction in the incidence of cervical carcinoma and serve as the prototype for comprehensive efforts to combat virus-induced tumors.
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Affiliation(s)
- Daniel DiMaio
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut 06510, USA
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18
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Pelosi G, Schianchi E, Dell'orto P, Veronesi G, Spaggiari L, Pasini F, Sozzi G, Brambilla E, Griso C, Viale G. Detecting cell-free circulating hTERT mRNA in the plasma may identify a subset of nonsmall cell lung cancer patients. Virchows Arch 2005; 448:7-15. [PMID: 16193293 DOI: 10.1007/s00428-005-0087-z] [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] [Received: 06/29/2005] [Accepted: 08/31/2005] [Indexed: 10/25/2022]
Abstract
Human telomerase reverse transcriptase (hTERT), the catalytic subunity of telomerase, a marker of cell immortalization, is upregulated in most tumors, including nonsmall cell lung cancer (NSCLC). However, little is known about the role of assessing cell-free plasma circulating hTERT mRNA for tracing these tumors. We investigated by RT-polymerase chain reaction (PCR) and real-time quantitative PCR the prevalence and functional implications of hTERT mRNA in both tumor tissue and paired plasma samples in 34 (27 males and 7 females) stages I-IIIB NSCLC patients (21 adenocarcinomas and 13 squamous-cell carcinomas) by using intron- and exon-spanning primers. Plasma samples of ten healthy volunteers and normal lung tissue were used as negative controls. We detected hTERT mRNA in the plasma of 4 out of 34 (12%) tumor patients, but none was detected in the ten plasma samples of healthy volunteers. Normal lung tissue was completely devoid of hTERT mRNA. No association was found between hTERT plasma mRNA and clinicopathologic variables of the patients' population. We conclude that cell-free circulating hTERT mRNA is detectable in a subset of patients, whereas it is consistently absent in healthy volunteers. It can be added to the panel of multiple genetic tracers to detect lung cancer in the plasma of patients, although, per se, it is not specific for this tumor.
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Affiliation(s)
- Giuseppe Pelosi
- Division of Pathology and Laboratory Medicine, European Institute of Oncology and University of Milan School of Medicine, Milan, Italy.
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Dong CK, Masutomi K, Hahn WC. Telomerase: regulation, function and transformation. Crit Rev Oncol Hematol 2005; 54:85-93. [PMID: 15843091 DOI: 10.1016/j.critrevonc.2004.12.005] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/14/2004] [Indexed: 01/10/2023] Open
Abstract
Work from several laboratories over the past decade indicates that the acquisition of constitutive telomerase expression is a critical step during the malignant transformation of human cells. Normal human cells transiently express low levels of telomerase, the ribonucleoprotein responsible for extending and maintaining telomeres, and exhibit telomere shortening after extended passage, whereas most cancers exhibit constitutive telomerase expression and maintain telomeres at stable lengths. These observations establish a direct connection between immortalization and stabilization of telomere structure. However, recent work suggests that telomerase also contributes to cancer development beyond its role in maintaining stable telomere lengths. In this review, we summarize recent observations that support the concept that telomerase plays multiple roles in facilitating human cell transformation.
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Affiliation(s)
- Carolyn K Dong
- Department of Medical Oncology, Dana-Farber Cancer Institute, Brigham and Women's Hospital and Harvard Medical School, 44 Binney Street, Boston, MA 02115, USA
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20
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N/A, 齐 义, 王 立. N/A. Shijie Huaren Xiaohua Zazhi 2005; 13:1317-1321. [DOI: 10.11569/wcjd.v13.i11.1317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/26/2023] Open
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21
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Lantuejoul S, Soria JC, Morat L, Lorimier P, Moro-Sibilot D, Sabatier L, Brambilla C, Brambilla E. Telomere Shortening and Telomerase Reverse Transcriptase Expression in Preinvasive Bronchial Lesions. Clin Cancer Res 2005; 11:2074-82. [PMID: 15756034 DOI: 10.1158/1078-0432.ccr-04-1376] [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: 11/16/2022]
Abstract
PURPOSE Telomerase, a ribonucleoprotein complex whose activity is related to the expression of its catalytic subunit human telomerase reverse transcriptase (hTERT), restores telomere length in tumor cells and enables immortality after p53/Rb inactivation has been achieved. To determine the timing of hTERT derepression during bronchial carcinogenesis and its relationship with telomere shortening and the p53/Rb pathway alterations, we did an immunohistochemical and in situ hybridization study in preinvasive and invasive bronchial lesions. EXPERIMENTAL DESIGN hTERT, P53, P16, cyclin D1, Bax-to-Bcl2 ratio, and Ki67 immunostainings were done in 106 preneoplastic lesions and in paired lung carcinoma and normal bronchial mucosae. Concomitantly, hTERT mRNA levels and qualitative telomere shortening were assessed by in situ hybridization and fluorescence in situ hybridization, respectively, in a subset of preneoplastic and neoplastic lesions. RESULTS Telomerase was increasingly expressed from normal epithelium to squamous metaplasia, dysplasia, and carcinoma in situ, and decreased in invasive carcinoma (P < 0.0001), with a direct correlation between protein and mRNA levels of expression (P < 0.0001). hTERT expression was directly correlated with P53, Ki67, and Bcl2-to-Bax ratio, suggesting a coupling between telomerase reactivation, proliferation, and resistance to apoptosis. Telomere signals significantly decreased as early as squamous metaplasia and progressively increased over the spectrum of preneoplastic lesions. CONCLUSIONS Telomere shortening represents an early genetic abnormality in bronchial carcinogenesis, preceding telomerase expression and p53/Rb inactivation, which predominate in high-grade preinvasive lesions.
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Affiliation(s)
- Sylvie Lantuejoul
- Department of Pathology, Centre Hospitalier Universitaire Albert Michallon, 38043 Grenoble Cedex 9, France
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Abstract
Telomeres, located at the ends of eukaryotic chromosomes, are synthesized by the enzyme telomerase and are responsible for maintaining chromosome length. The absence of telomerase in most somatic cells has been associated with telomere shortening and aging of these cells. In contrast, high levels of telomerase activity are observed in over 90% of human cancer cells. The absence of telomerase in normal and aging cells is considered a natural defense against development of cancer. However, we do not know 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 believed to be controlled primarily at the level of transcription. Elucidation of the control of telomerase in aging and in cancer as an age-related disease has considerable potential in leading to novel approaches in anti-aging medicine.
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Affiliation(s)
- Ali Ahmed
- University of Alabama at Birmingham, Birmingham, Alabama 35294, USA.
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23
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Golubev A, Khrustalev S, Butov A. An in silico investigation into the causes of telomere length heterogeneity and its implications for the Hayflick limit. J Theor Biol 2004; 225:153-70. [PMID: 14575650 DOI: 10.1016/s0022-5193(03)00229-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
UNLABELLED In telomerase-negative cell populations the mean telomere length (TL) decreases with increasing population doubling number (PD). A critically small TL is believed to stop cell proliferation at a cell-, age- and species-specific PD thus defining the Hayflick limit. However, positively skewed TL distributions are broad compared to differences between initial and final mean TL and strongly overlap at middle and late PD, which is inconsistent with a limiting role of TL. We used computer-assisted modelling to define what set of premises may account for the above. Our model incorporates the following concepts. DNA end replication problem: telomeres loose 1 shortening unit (SU) upon each cell division. Free radical-caused TL decrease: telomeres experience random events resulting in the loss of a random SU number within a remaining TL. Stochasticity of gene expression and cell differentiation: cells experience random events inducing mitoses or committing cells to proliferation arrest, the latter option requiring a specified number of mitoses to be passed. Cells whose TL reaches 1SU cannot divide. The proliferation kinetics of such virtual cells conforms to the transition probability model of cell cycle. When no committing events occur and at realistic SU estimates of the initial TL, maximal PD values far exceed the Hayflick limit observed in normal cells and are consistent with the crisis stage entered by transformed cells that have surpassed the Hayflick limit. At intermediate PD, symmetrical TL distributions are yielded. Upon introduction of committing events making the ratio of the rates of proliferating and committing events (P/C) range from 1.10 to 1.25, TL distributions at intermediate PD become positively skewed, and virtual cell clones show bimodal size distributions. At P/C as high as 1.25 the majority of virtual cells at maximal PD contain telomeres with TL>1SU. A 10% increase in P/C within the 1.10-1.25 range produces a two-fold increase in the maximal PD, which can reach values of up to 25 observed in rodent and some human cells. Increasing the number of committed mitoses from 0 to 10 can increases PD to about 50 observed in human fibroblasts. Introduction of the random TL breakage makes the shapes of TL distributions quite dissimilar from those observed in real cells. CONCLUSIONS Telomere length decrease is a correlate of cell proliferation that cannot alone account for the Hayflick limit, which primarily depends on parameters of cell population kinetics. Free radical damage influences the Hayflick limit not through TL but rather by affecting the ratio of the rates of events that commit cells to mitoses or to proliferation arrest.
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Affiliation(s)
- A Golubev
- Research Institute of Experimental Medicine, St. Petersburg, Russia.
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24
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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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25
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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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26
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Han Z, Wei W, Dunaway S, Darnowski JW, Calabresi P, Sedivy J, Hendrickson EA, Balan KV, Pantazis P, Wyche JH. Role of p21 in apoptosis and senescence of human colon cancer cells treated with camptothecin. J Biol Chem 2002; 277:17154-60. [PMID: 11877436 DOI: 10.1074/jbc.m112401200] [Citation(s) in RCA: 186] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Treatment of cells with the anti-cancer drug camptothecin (CPT) induces topoisomerase I (Top1)-mediated DNA damage, which in turn affects cell proliferation and survival. In this report, we demonstrate that treatment of the wild-type HCT116 (wt HCT116) human colon cancer cell line and the isogenic p53(-/-) HCT116 and p21(-/-) HCT116 cell lines with a high concentration (250 nm) of CPT resulted in apoptosis, indicating that apoptosis occurred by a p53- and p21-independent mechanism. In contrast, treatment with a low concentration (20 nm) of CPT induced cell cycle arrest and senescence of the wt HCT116 cells, but apoptosis of the p53(-/-) HCT116 and p21(-/-) HCT116 cells. Further investigations indicated that p53-dependent expression of p21 blocked apoptosis of wt HCT116 cells treated with 20 nm, but not 250 nm CPT. Interestingly, blocking of the apoptotic pathway, by Z-VAD-FMK, in p21(-/-) HCT116 cells following treatment with 20 nm CPT did not permit the cells to develop properties of senescence. These observations demonstrated that p21 was required for senescence development of HCT116 cells following treatment with low concentrations of CPT.
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Affiliation(s)
- Zhiyong Han
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, Rhode Island 02912, USA.
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Shimazui T, Ami Y, Miyanaga N, Ideyama Y, Nakahara T, Akaza H. Telomerase is upregulated in irreversible preneoplastic lesions during bladder carcinogenesis in rats. Jpn J Cancer Res 2002; 93:495-500. [PMID: 12036444 PMCID: PMC5927038 DOI: 10.1111/j.1349-7006.2002.tb01283.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Multiple occurrence or recurrence after transurethral resection is an important characteristic of superficial bladder tumors. To study bladder carcinogenesis, we focused on detection of telomerase activation, which was investigated in several human cancers, including bladder tumors. We experimentally examined the telomerase activity during bladder carcinogenesis, especially in precancerous lesions, induced by N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) in rats. Male Wistar rats were given 0.05% BBN in water from the age of 8 weeks to 24 weeks. Subgroups were euthanized at 4, 8, 10, 12, 18, and 24 weeks after BBN administration. Using the stretch PCR method, telomerase activity was semiquantified in exfoliated bladder epithelial cells. In addition, telomere length in each subgroup was measured by southern hybridization for the terminal restriction fragment using a (TTAGGG)(4) probe. Statistical analyses were performed using analysis of variance and Fisher's PLSD test. Epithelial cells of normal bladder in the control groups and those of diffuse hyperplasia, which was a reversible change at 4 weeks, expressed no telomerase activity. In contrast, telomerase activity significantly increased in the stage after nodular hyperplasia, an irreversible change at 8 weeks, then elevated with carcinogenesis. However, telomere length was still preserved by the 12th week, and was shortened at 18 and 24 weeks. These results suggest that telomerase activation is probably induced independent of telomere shortening during bladder carcinogenesis in the rat, and might be a biological tumor marker of irreversible preneoplastic lesions, which evolve into bladder tumors in the rat.
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Affiliation(s)
- Toru Shimazui
- Department of Urology, Institute of Clinical Medicine, University of Tsukuba, Tsukuba 305-8575.
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28
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Mergny JL, Riou JF, Mailliet P, Teulade-Fichou MP, Gilson E. Natural and pharmacological regulation of telomerase. Nucleic Acids Res 2002; 30:839-65. [PMID: 11842096 PMCID: PMC100331 DOI: 10.1093/nar/30.4.839] [Citation(s) in RCA: 273] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2001] [Revised: 11/29/2001] [Accepted: 11/29/2001] [Indexed: 01/14/2023] Open
Abstract
The extremities of eukaryotic chromosomes are called telomeres. They have a structure unlike the bulk of the chromosome, which allows the cell DNA repair machinery to distinguish them from 'broken' DNA ends. But these specialised structures present a problem when it comes to replicating the DNA. Indeed, telomeric DNA progressively erodes with each round of cell division in cells that do not express telomerase, a specialised reverse transcriptase necessary to fully duplicate the telomeric DNA. Telomerase is expressed in tumour cells but not in most somatic cells and thus telomeres and telomerase may be proposed as attractive targets for the discovery of new anticancer agents.
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Affiliation(s)
- Jean-Louis Mergny
- Laboratoire de Biophysique, Muséum National d'Histoire Naturelle, INSERM U 201, CNRS UMR 8646, 43 rue Cuvier, F-75005 Paris, France.
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29
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Abstract
In the decade since the telomere hypothesis of cellular aging was proposed, the two essential genes for human telomerase were cloned and characterized, allowing experimental proof of the causal relationships between telomere loss and replicative senescence, and telomerase activation and immortalization. These relationships were established using a variety of cultured human cell types from both normal and tumor tissues, and were largely confirmed in the telomerase knockout mouse. Taken together, the data provide strong support for the potential utility of telomerase detection and inhibition for cancer, and telomerase activation for degenerative diseases. The specificity of the promoter for the telomerase catalytic gene and the antigenicity of the protein product, hTERT, provide additional strategies for killing telomerase-positive tumor cells. Unfortunately, the strong link between telomerase and cancer has led some to confuse telomerase activation with cancer, and others to overstate the cancer risk of telomerase activation therapies for degenerative diseases. This review clarifies the difference between telomerase, which does not cause growth deregulation, and oncogenes, which do. It also addresses the concept of telomerase repression as a tumor suppressor mechanism early in life, with detrimental tissue degeneration and tumor-promoting consequences late in life. This extended view of the telomere hypothesis helps explain how telomerase inhibition can be therapeutic in cancer patients, while controlled telomerase activation for degenerative diseases may actually reduce, rather than increase, the frequency of age-related tumorigenesis.
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Abstract
We report that recombination rates specifically increase by up to 10(3) near shortened telomeres in K. lactis cells. This occurs in cells lacking telomerase that undergo growth senescence as well as in cells with stably shortened telomeres that cause little effect on cell growth. The high rates of gene conversion allowed a subtelomeric marker, initially present at a single telomere, to efficiently spread to most or all other telomeres in the cell. We propose that short telomeres in K. lactis are not fully competent at capping chromosome ends and hence are occasionally processed by proteins that normally act to repair broken DNA ends through recombination. This helps explain how recombination can be frequent enough to permit maintenance of telomeres in yeast cells lacking telomerase.
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Affiliation(s)
- M J McEachern
- Department of Genetics, Life Sciences Building, C318, University of Georgia, Athens, GA 30602, USA.
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31
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Ding W, Gao S, Scott RE. Senescence represses the nuclear localization of the serum response factor and differentiation regulates its nuclear localization with lineage specificity. J Cell Sci 2001; 114:1011-8. [PMID: 11181183 DOI: 10.1242/jcs.114.5.1011] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The differentiation of cultured 3T3T mesenchymal stem cells into adipocytes represses growth factor responsiveness by limiting the nuclear localization of the serum response factor (SRF) that binds to and activates the promoters of growth control genes that contain the serum response elements (SRE), such as junB and c-fos. The regulation of SRF nuclear localization by adipocyte differentiation is specific, because we show that adipocyte differentiation does not repress the nuclear localization of six other transacting factors. To determine if repression of growth factor responsiveness that occurs during senescence also represses the nuclear localization of SRF, we studied normal human WI-38 fibroblasts at low versus high population doublings. The results show that SRF localizes to the nucleus of proliferative cells whereas in senescent cells SRF can not be detected in the nucleus. This result is apparent in both immunofluorescence assays and in western blot analysis. We next evaluated the cellular distribution of SRF in selected human tissues to determine whether the loss of proliferative potential in vivo could have a different effect on SRF nuclear localization. We found that in cells of the small bowel mucosa, differentiation modulates SRF nuclear localization in an opposite manner. Minimal SRF expression and nuclear localization is evident in undifferentiated cells at the base of crypts whereas increased SRF expression and nuclear localization is evident in differentiated cells at the surface tip of the villus. These results together establish that regulation of SRF expression and nuclear localization is important in senescence and differentiation in a lineage specific manner.
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Affiliation(s)
- W Ding
- Department of Pathology, University of Tennessee Health Science Center, Memphis, TN 38163, USA
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Sakaguchi M, Tsuji T, Inoue Y, Miyazaki M, Namba M, Yamada H, Tanaka T. Loss of nuclear localization of the S100C protein in immortalized human fibroblasts. Radiat Res 2001; 155:208-214. [PMID: 11121236 DOI: 10.1667/0033-7587(2001)155[0208:lonlot]2.0.co;2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
It is well known that cancer develops through a multistep process. In vitro transformation studies of normal human cells have shown that the immortalization step is critical for neoplastic transformation of cells. Furthermore, studies of cell fusion between normal and immortalized cells have indicated that the normal phenotype is dominant and the immortal phenotype is recessive. Thus we looked for cellular proteins that were down-regulated in immortalized human cells by two-dimensional gel electrophoresis to elucidate the mechanisms of immortalization of human cells. We found that the S100C protein was down-regulated in immortalized cells. This protein was localized in the cytoplasm of cells at the semiconfluent stage, while at the confluent stage it moved into the nuclei of normal cells but not into those of immortalized cells. Microinjection of an S100C antibody into normal confluent cells diminished the level of nuclear S100C protein, resulting in DNA synthesis. Taken together, loss of nuclear localization of the S100C protein, which may be related to DNA synthesis, is thought to be one of the mechanisms of immortalization.
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Affiliation(s)
- M Sakaguchi
- Department of Cell Biology, Institute of Cellular and Molecular Biology, Okayama University Medical School, Okayama 700-8558, Japan
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Abstract
The process by which normal cells become progressively transformed to malignancy is now known to require the sequential acquisition of mutations which arise as a consequence of damage to the genome. This damage can be the result of endogenous processes such as errors in replication of DNA, the intrinsic chemical instability of certain DNA bases or from attack by free radicals generated during metabolism. DNA damage can also result from interactions with exogenous agents such as ionizing radiation, UV radiation and chemical carcinogens. Cells have evolved means to repair such damage, but for various reasons errors occur and permanent changes in the genome, mutations, are introduced. Some inactivating mutations occur in genes responsible for maintaining genomic integrity facilitating the acquisition of additional mutations. This review seeks first to identify sources of mutational damage so as to identify the basic causes of human cancer. Through an understanding of cause, prevention may be possible. The evolution of the normal cell to a malignant one involves processes by which genes involved in normal homeostatic mechanisms that control proliferation and cell death suffer mutational damage which results in the activation of genes stimulating proliferation or protection against cell death, the oncogenes, and the inactivation of genes which would normally inhibit proliferation, the tumor suppressor genes. Finally, having overcome normal controls on cell birth and cell death, an aspiring cancer cell faces two new challenges: it must overcome replicative senescence and become immortal and it must obtain adequate supplies of nutrients and oxygen to maintain this high rate of proliferation. This review examines the process of the sequential acquisition of mutations from the prospective of Darwinian evolution. Here, the fittest cell is one that survives to form a new population of genetically distinct cells, the tumor. This review does not attempt to be comprehensive but identifies key genes directly involved in carcinogenesis and demonstrates how mutations in these genes allow cells to circumvent cellular controls. This detailed understanding of the process of carcinogenesis at the molecular level has only been possible because of the advent of modern molecular biology. This new discipline, by precisely identifying the molecular basis of the differences between normal and malignant cells, has created novel opportunities and provided the means to specifically target these modified genes. Whenever possible this review highlights these opportunities and the attempts being made to generate novel, molecular based therapies against cancer. Successful use of these new therapies will rely upon a detailed knowledge of the genetic defects in individual tumors. The review concludes with a discussion of how the use of high throughput molecular arrays will allow the molecular pathologist/therapist to identify these defects and direct specific therapies to specific mutations.
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Affiliation(s)
- J S Bertram
- Cancer Research Center of Hawaii, University of Hawaii at Manoa, 1236 Lauhala Street, Honolulu, HI 96813, USA.
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