• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Molecular and Cellular Biology >A Two-Stage, p16INK4A- and p53-Dependent Keratinocyte Senescence Mechanism That Limits Replicative Potential Independent of Telomere Status
【24h】

A Two-Stage, p16INK4A- and p53-Dependent Keratinocyte Senescence Mechanism That Limits Replicative Potential Independent of Telomere Status

机译：两阶段，p16INK4A和p53依赖的角质形成细胞衰老机制，限制复制潜能与端粒状态无关

获取原文
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

With increasing frequency during serial passage in culture, primary human keratinocytes express p16INK4A (p16) and undergo senescence arrest. Keratinocytes engineered to express hTERT maintain long telomeres but typically are not immortalized unless, by mutation or other heritable event, they avoid or greatly reduce p16 expression. We have confirmed that keratinocytes undergo p16-related senescence during growth in culture, whether in the fibroblast feeder cell system or in the specialized K-sfm medium formulation, and that this mechanism can act as a barrier to immortalization following hTERT expression. We have characterized the p16-related arrest mechanism more precisely by interfering specifically with several regulators of cell cycle control. Epidermal, oral mucosal, corneal limbal, and conjunctival keratinocytes were transduced to express a p16-insensitive mutant cdk4 (cdk4R24C), to abolish p16 control, and/or a dominant negative mutant p53 (p53DD), to abolish p53 function. Expression of either cdk4R24C or p53DD alone had little effect on life span, but expression of both permitted cells to divide 25 to 43 population doublings (PD) beyond their normal limit. Keratinocytes from a p16+/? individual transduced to express p53DD alone displayed a 31-PD life span extension associated with selective growth of variants that had lost the wild-type p16 allele. Cells in which both p53 and p16 were nonfunctional divided rapidly during their extended life span but experienced telomere erosion and ultimately ceased growth with very short telomeres. Expression of hTERT in these cells immortalized them. Keratinocytes engineered to express cdk4R24C and hTERT but not p53DD did not exhibit an extended life span. Rare immortal variants exhibiting p53 pathway defects arose from them, however, indicating that the p53-dependent component of keratinocyte senescence is telomere independent. Mutational loss of p16 and p53 has been found to be a frequent early event in the development of squamous cell carcinoma. Our results suggest that such mutations endow keratinocytes with extended replicative potential which may serve to increase the probability of neoplastic progression.
机译：随着培养中连续传代的频率增加，原代人角质形成细胞表达p16 INK4A （p16）并经历衰老停滞。经过工程改造以表达hTERT的角质形成细胞可维持较长的端粒，但通常不会永生，除非通过突变或其他可遗传事件避免或大大降低p16表达。我们已经证实，无论在成纤维细胞饲养细胞系统中还是在专门的K-sfm培养基配方中，在培养过程中，角质形成细胞都会经历p16相关的衰老，并且这种机制可成为hTERT表达后永生化的障碍。通过特别干扰细胞周期控制的几种调节剂，我们已经更精确地表征了p16相关的阻滞机制。转导了表皮，口腔粘膜，角膜缘和结膜角质形成细胞，以表达p16不敏感突变体cdk4（cdk4 R24C ），废除p16对照和/或显性阴性突变体p53（p53DD），取消p53功能。单独使用cdk4 R24C 或p53DD的表达对寿命几乎没有影响，但是两种表达的表达都允许细胞分裂超过正常极限的25到43个群体倍增（PD）。被转导为单独表达p53DD的 p16 + /？ 个体的角质形成细胞显示31-PD寿命延长，与失去野生型 p16 等位基因。 p53和p16均不起作用的细胞在其延长的寿命中迅速分裂，但经历了端粒腐蚀，最终由于非常短的端粒而停止生长。 hTERT在这些细胞中的表达使它们永生。工程化表达cdk4 R24C 和hTERT而不表达p53DD的角质形成细胞不具有延长的寿命。从中出现了罕见的具有p53途径缺陷的不朽变体，但是，这表明角质形成细胞衰老的p53依赖性成分与端粒无关。已经发现p16和p53的突变丢失是鳞状细胞癌发展中的常见早期事件。我们的结果表明，这种突变赋予角质形成细胞以扩大的复制潜能，这可能有助于增加肿瘤进展的可能性。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号