The Escape of Temperature-Sensitive T Antigen Immortalized Rat Hepatocytes from Conditional Immortalization
Conditionally immortalized hepatocytes (CIH) established with a gene for the temperature-sensitive mutant of the T antigen (tsT) have characteristics to stop proliferating and to differentiate at nonpermissive temperatures (37—39°C) due to inactivation of the T antigen. Therefore, they may be a good...
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doaj-40d0465c80f0432ba35dd91888f756182020-11-25T03:20:54ZengSAGE PublishingCell Transplantation0963-68971555-38922005-08-011410.3727/000000005783982864The Escape of Temperature-Sensitive T Antigen Immortalized Rat Hepatocytes from Conditional ImmortalizationByung-Ho Kim M.D.0Yo Seb Han1Bong-Keun Choe2Hyeseong Cho3Gi Deog Nam4Jin Woo Lee5Young Il Kim6Jai Kyung Park7Seok Ho Dong8Hyo Jong Kim9Young Woon Chang10Joung Il Lee11Rin Chang12Department of Internal Medicine, Kyung Hee University College of Medicine, Seoul 130—702, KoreaDepartment of Internal Medicine, Kyung Hee University College of Medicine, Seoul 130—702, KoreaPreventive Medicine, Kyung Hee University College of Medicine, Seoul 130—702, KoreaDepartment of Biochemistry, Ajou Universtiy School of Medicine, Suwon 447—749, KoreaDepartment of Internal Medicine, Kyung Hee University College of Medicine, Seoul 130—702, KoreaDepartment of Internal Medicine, Kyung Hee University College of Medicine, Seoul 130—702, KoreaDepartment of Internal Medicine, Kyung Hee University College of Medicine, Seoul 130—702, KoreaDepartment of Internal Medicine, Kyung Hee University College of Medicine, Seoul 130—702, KoreaDepartment of Internal Medicine, Kyung Hee University College of Medicine, Seoul 130—702, KoreaDepartment of Internal Medicine, Kyung Hee University College of Medicine, Seoul 130—702, KoreaDepartment of Internal Medicine, Kyung Hee University College of Medicine, Seoul 130—702, KoreaDepartment of Internal Medicine, Kyung Hee University College of Medicine, Seoul 130—702, KoreaDepartment of Internal Medicine, Kyung Hee University College of Medicine, Seoul 130—702, KoreaConditionally immortalized hepatocytes (CIH) established with a gene for the temperature-sensitive mutant of the T antigen (tsT) have characteristics to stop proliferating and to differentiate at nonpermissive temperatures (37—39°C) due to inactivation of the T antigen. Therefore, they may be a good alternative to primary hepatocytes for experimental investigations or clinical applications. Deinduction of the T antigen results in a transient increase of p53 in these cells, leading to reexpression of normal senescence because of the telomere attrition occurring during the early stages of immortalization. To determine this T antigen dependency for the maintenance of immortality, a type of rat CIH was cultured continuously at 39°C. The frequency of occurrence of T-antigen-independent clones ranged from 0.053% to 0.093%. These clones maintained the temperature-sensitive property of the T antigen; nevertheless, they were able to progress to the S phase and proliferate without undergoing apoptosis at 39°C as at 33°C, a permissive temperature. The temperature-sensitive point mutation of tsT was not affected in these clones and the T antigen was functioning properly. The integrity of the p53 pathway was also maintained from the point of Western blot analysis of p21. Although the telomerase continued to be expressed and the telomere length was maintained, marked chromosomal damage could not be avoided in these cells. It is a plausible explanation that this escape phenomenon from conditional immortalization may be related to the change of other genes involved in cell cycles, which have yet to be elucidated. In conclusion, CIH could lose their temperature-sensitive characteristics without the change of tsT, itself, and the T antigen is not always necessary to maintain their immortality. Therefore, the results obtained from experimental investigations using these cells should be interpreted carefully, and unpredictable phenotypic changes should also be taken into consideration when using them in clinical applications.https://doi.org/10.3727/000000005783982864 |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Byung-Ho Kim M.D. Yo Seb Han Bong-Keun Choe Hyeseong Cho Gi Deog Nam Jin Woo Lee Young Il Kim Jai Kyung Park Seok Ho Dong Hyo Jong Kim Young Woon Chang Joung Il Lee Rin Chang |
spellingShingle |
Byung-Ho Kim M.D. Yo Seb Han Bong-Keun Choe Hyeseong Cho Gi Deog Nam Jin Woo Lee Young Il Kim Jai Kyung Park Seok Ho Dong Hyo Jong Kim Young Woon Chang Joung Il Lee Rin Chang The Escape of Temperature-Sensitive T Antigen Immortalized Rat Hepatocytes from Conditional Immortalization Cell Transplantation |
author_facet |
Byung-Ho Kim M.D. Yo Seb Han Bong-Keun Choe Hyeseong Cho Gi Deog Nam Jin Woo Lee Young Il Kim Jai Kyung Park Seok Ho Dong Hyo Jong Kim Young Woon Chang Joung Il Lee Rin Chang |
author_sort |
Byung-Ho Kim M.D. |
title |
The Escape of Temperature-Sensitive T Antigen Immortalized Rat Hepatocytes from Conditional Immortalization |
title_short |
The Escape of Temperature-Sensitive T Antigen Immortalized Rat Hepatocytes from Conditional Immortalization |
title_full |
The Escape of Temperature-Sensitive T Antigen Immortalized Rat Hepatocytes from Conditional Immortalization |
title_fullStr |
The Escape of Temperature-Sensitive T Antigen Immortalized Rat Hepatocytes from Conditional Immortalization |
title_full_unstemmed |
The Escape of Temperature-Sensitive T Antigen Immortalized Rat Hepatocytes from Conditional Immortalization |
title_sort |
escape of temperature-sensitive t antigen immortalized rat hepatocytes from conditional immortalization |
publisher |
SAGE Publishing |
series |
Cell Transplantation |
issn |
0963-6897 1555-3892 |
publishDate |
2005-08-01 |
description |
Conditionally immortalized hepatocytes (CIH) established with a gene for the temperature-sensitive mutant of the T antigen (tsT) have characteristics to stop proliferating and to differentiate at nonpermissive temperatures (37—39°C) due to inactivation of the T antigen. Therefore, they may be a good alternative to primary hepatocytes for experimental investigations or clinical applications. Deinduction of the T antigen results in a transient increase of p53 in these cells, leading to reexpression of normal senescence because of the telomere attrition occurring during the early stages of immortalization. To determine this T antigen dependency for the maintenance of immortality, a type of rat CIH was cultured continuously at 39°C. The frequency of occurrence of T-antigen-independent clones ranged from 0.053% to 0.093%. These clones maintained the temperature-sensitive property of the T antigen; nevertheless, they were able to progress to the S phase and proliferate without undergoing apoptosis at 39°C as at 33°C, a permissive temperature. The temperature-sensitive point mutation of tsT was not affected in these clones and the T antigen was functioning properly. The integrity of the p53 pathway was also maintained from the point of Western blot analysis of p21. Although the telomerase continued to be expressed and the telomere length was maintained, marked chromosomal damage could not be avoided in these cells. It is a plausible explanation that this escape phenomenon from conditional immortalization may be related to the change of other genes involved in cell cycles, which have yet to be elucidated. In conclusion, CIH could lose their temperature-sensitive characteristics without the change of tsT, itself, and the T antigen is not always necessary to maintain their immortality. Therefore, the results obtained from experimental investigations using these cells should be interpreted carefully, and unpredictable phenotypic changes should also be taken into consideration when using them in clinical applications. |
url |
https://doi.org/10.3727/000000005783982864 |
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