Low-dose radiation stimulates the proliferation of normal human lung fibroblasts via a transient activation of Raf and Akt

Cha Soon Kim, Jin Kyoung Kim, Seon Young Nam, Kwang Hee Yang, Meeseon Jeong, Hee Sun Kim, Chong Soon Kim, Young Woo Jin, Joon Kim

Research output: Contribution to journalArticle

42 Citations (Scopus)

Abstract

The biological effects of low-dose radiation have been investigated and debated for more than a century, but its cellular effects and regulatory mechanisms remain poorly understood. This study shows the human cellular responses to low-dose radiation in CCD-18 Lu cells, which are derived from normal human lung fibroblasts. We examined a colony-forming assay for cell survival by ionizing radiation. Live cell counting and cell cycle analysis were measured for cell proliferation and cell cycle progression following low-dose irradiation. We examined Raf and Akt phosphorylation to determine the proliferation mechanism resulting from low-dose radiation. We also observed that p53 and p21 were related to cell cycle response. We found that 0.05 Gy of ionizing radiation enhanced cell proliferation and did not change the progression of the cell cycle. In addition, 0.05 Gy of ionizing radiation transiently activated Raf and Akt, but did not change phospho-p53, p53 and p21 in CCD-18 Lu cells. However, 2 Gy of ionizing radiation induced cell cycle arrest, phosphorylation of p53, and expression of p53 and p21. The phosphorylation of Raf and Akt proteins induced by 0.05 Gy of ionizing radiation was abolished by pre-treatment with an EGFR inhibitor, AG1479, or a PI3k inhibitor, LY294002. Cell proliferation stimulated by 0.05 Gy of ionizing radiation was blocked by the suppression of Raf and Akt phosphorylation with these inhibitors. These results suggest that 0.05 Gy of ionizing radiation stimulates cell proliferation through the transient activation of Raf and Akt in CCD-18 Lu cells.

Original languageEnglish
Pages (from-to)424-430
Number of pages7
JournalMolecules and cells
Volume24
Issue number3
Publication statusPublished - 2007 Dec 31

Keywords

  • Akt
  • Cell proliferation
  • Low-dose radiation
  • Normal human diploid cells
  • Raf

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology

Fingerprint Dive into the research topics of 'Low-dose radiation stimulates the proliferation of normal human lung fibroblasts via a transient activation of Raf and Akt'. Together they form a unique fingerprint.

  • Cite this

    Kim, C. S., Kim, J. K., Nam, S. Y., Yang, K. H., Jeong, M., Kim, H. S., Kim, C. S., Jin, Y. W., & Kim, J. (2007). Low-dose radiation stimulates the proliferation of normal human lung fibroblasts via a transient activation of Raf and Akt. Molecules and cells, 24(3), 424-430.