Activation of FKHRL1 plays an important role in protecting erythroid cells from erythropoietin deprivation-induced apoptosis in a human erythropoietin-dependent leukemia cell line, UT-7/EPO
Language: 
English
Abstract: 

FKHRL1 is one of the human homologues of DAF-16, which is concerned with longevity in Caenorhabditis elegans. Previously, we demonstrated that FKHRL1 functions downstream of Akt in erythropoietin (EPO) signaling and that it is directly phosphorylated by activated Akt. Because phosphorylated FKHRL1 loses its transcriptional activity and translocates into the cytoplasm, FKHRL1 appears to be nonfunctional in the presence of EPO. Conversely, EPO deprivation leads to FKHRL1 dephosphorylation and its translocation into the nucleus, suggesting that FKHRL1 becomes active as a transcription factor in the absence of EPO. On the basis of these findings, we hypothesized, by analogy with C elegans, that erythroid cells possess self-defense machinery against life-threatening surroundings. We prepared a dominant-negative mutant of FKHRL1 (FKHRL1-DN) lacking the transactivation domain and prepared FKHRL1 small interfering RNA (siRNA), and we used constructs to transfect a human EPO-dependent cell line, UT-7/EPO. In the parental cells, 24-hour EPO deprivation induced transient cell cycle arrest without apoptosis. On the other hand, stable transfectants expressing FKHRL1-DN or FKHRL1 siRNA underwent rapid apoptosis after EPO deprivation in the UT-7/EPO cells. In conclusion, FKHRL1 activation plays an important role in the extension of survival of erythroid cells after EPO deprivation. This phenomenon appears to correspond to dauer formation in C elegans. Thus, the mechanism of lifespan extension may be broadly conserved from C elegans to humans.

Author(s): 
Uchida, Mie
Kirito, Keita
Endo, Hitoshi
Ozawa, Keiya
Komatsu, Norio
Item Type: 
Journal Article
Publication Title: 
International Journal of Hematology
Journal Abbreviation: 
Int. J. Hematol.
Publication Date: 
2007-11
Publication Year: 
2007
Pages: 
315-324
Volume: 
86
Issue: 
4
ISSN: 
0925-5710
DOI: 
10.1532/IJH97.07093
Library Catalog: 
NCBI Published Medical (?)
Extra: 
PMID: 18055337

Turabian/Chicago Citation

Mie Uchida, Keita Kirito, Hitoshi Endo, Keiya Ozawa and Norio Komatsu. 2007-11. "Activation of FKHRL1 plays an important role in protecting erythroid cells from erythropoietin deprivation-induced apoptosis in a human erythropoietin-dependent leukemia cell line, UT-7/EPO." International Journal of Hematology 86: 4: 315-324. 10.1532/IJH97.07093.

Wikipedia Citation

<ref> {{Cite journal | doi = 10.1532/IJH97.07093 | issn = 0925-5710 | volume = 86 | pages = 315-324 | last = Uchida | first = Mie | coauthors = Kirito, Keita, Endo, Hitoshi, Ozawa, Keiya, Komatsu, Norio | title = Activation of FKHRL1 plays an important role in protecting erythroid cells from erythropoietin deprivation-induced apoptosis in a human erythropoietin-dependent leukemia cell line, UT-7/EPO | journal = International Journal of Hematology | date = 2007-11 | pmid = | pmc = }} </ref>