Blood, Vol. 95 No. 8 (April 15), 2000:
pp. 2715-2718
BRIEF REPORT
Constitutive activation of LIL-Stat in adult T-cell leukemia
cells
Junichi Tsukada,
Yoko Toda,
Masahiro Misago,
Yoshiya Tanaka,
Philip E. Auron, and
Sumiya Eto
From the First Department of Internal Medicine, School of Medicine,
and School of Health Sciences, University of Occupational and
Environmental Health, Kitakyushu, Japan; and The New England Baptist
Bone & Joint Institute, Beth Israel Deaconess Medical Center and
Department of Medicine, Harvard Medical School, Boston, MA.
The activation status of a recently identified STAT (signal
transducers and activators of transcription) factor, LIL-Stat (lipopolysaccharide [LPS]/IL-1-inducible Stat) in adult T-cell leukemia (ATL) cells was investigated by electrophoretic mobility shift
assays using nuclear extracts of leukemic cells from 7 patients with
ATL and a GAS (gamma interferon activation site)-like element termed
LILRE (LPS/IL-1-responsive element), which is found in the human
prointerleukin 1
(IL1B) gene. Spontaneous DNA binding of
LIL-Stat was observed in all ATL cells examined. However, in normal
human peripheral lymphocytes, DNA binding of LIL-Stat was detected only
after stimulation with IL-1. These results demonstrated that LIL-Stat
is constitutively activated in ATL cells. Furthermore, our transient
transfection studies using LILRE chloramphenicol acetyltransferase
(CAT) reporters argue that LIL-Stat in ATL cells functions as a
transcriptional activator through binding to the LILRE in the
IL1B gene.
