Human lactoferrin controls the level of retinoblastoma protein and its activity

Hee Joung Son, Shin Hee Lee, Sang-Yun Choi

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

Lactoferrin (Lf) has been implicated in the regulation of cell growth. However, the molecular mechanism underlying this effect remains to be elucidated. In this study, we show that Lf is involved in the cell cycle control system in a variety of cell lines, through retinoblastoma protein (Rb) - mediated growth arrest. We observed that Lf induces the expression of Rb, a signal mediator of cell cycle control, and that a majority of this Lf-induced Rb persists in a hypophosphorylated form. In addition, we determined that Lf specifically augments the level of a cyclin-dependent kinase inhibitor, p21, but not p27. Upon treatment with Lf, H1299 cells expressing defective p53 effected an augmentation of endogenous p21 levels, which may contribute to the accumulation of hypophosphorylated Rb. A substantial quantity of active Rb binds more efficiently to E2F1 in cells that express Lf and consequently blocks the expression of an E2F1-responsive gene, thereby suggesting that Lf plays a crucial role in the inhibition of tumor cell growth. Therefore, we conclude that the antiproliferative effects of Lf can likely be attributed to the elevated levels of hypophosphorylated Rb.

Original languageEnglish
Pages (from-to)345-350
Number of pages6
JournalBiochemistry and Cell Biology
Volume84
Issue number3
DOIs
Publication statusPublished - 2006 Jun 1

Fingerprint

Retinoblastoma Protein
Lactoferrin
Cells
Cell growth
Cell Cycle Checkpoints
Growth
Cyclin-Dependent Kinase Inhibitor p21
Tumors
Genes
Control systems
Cell Line

Keywords

  • Cyclin-dependent kinase inhibitor
  • E2F1
  • Lactoferrin
  • Retinoblastoma protein

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Biochemistry
  • Cell Biology

Cite this

Human lactoferrin controls the level of retinoblastoma protein and its activity. / Son, Hee Joung; Lee, Shin Hee; Choi, Sang-Yun.

In: Biochemistry and Cell Biology, Vol. 84, No. 3, 01.06.2006, p. 345-350.

Research output: Contribution to journalArticle

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