Prevention of thymic lymphoma development in Atm-/- mice by dexamethasone

Mingshan Yan, Xianghong Kuang, Wenan Qiang, Jianjun Shen, Kent Claypool, William S. Lynn, Paul K Y Wong

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


We have reported (M. Yan et al., FASEB J., 15: 1132-1138, 2001) that spontaneous DNA synthesis is markedly increased in the thymocytes from the atrophied thymi of young Am-/- mice. We, therefore, set out to determine whether this elevated DNA synthesis is responsible for the development of thymic lymphomas in all Atm-/- mice by 4-5 months of age. We show here that in Atm-/- mice: (a) increased DNA synthesis occurs, especially in the immature CD4- CD8- (dominant negative) and CD8+ thymocyte populations; (b) the relative percentage of dominant negative cells increases significantly during postnatal development, with a sharp peak at 4 weeks of age; and (c) dexamethasone suppresses DNA synthesis in these thymocytes and prevents thymic lymphoma development. These observations suggest that ataxia telangiectasia mutated (ATM) down-regulates the proliferation of thymocytes, allowing T-cell development and differentiation. The results also show that dexamethasone, like ATM, checks DNA synthesis in developing thymocytes. Finally, the data document for the first time that dexamethasone prevents or slows thymic lymphoma development in Atm-/- mice.

Original languageEnglish (US)
Pages (from-to)5153-5157
Number of pages5
JournalCancer Research
Issue number18
StatePublished - Sep 15 2002

ASJC Scopus subject areas

  • Oncology
  • Cancer Research


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