The role of calcium/calmodulin-dependent protein kinase cascade on MIP-1alpha gene expression of ATL cells.
OBJECTIVE
Adult T-cell leukemia (ATL) is a mature CD4(+) T-cell malignancy caused by infection with human T-lymphotrophic virus type-1 and is associated with a marked hypercalcemia in many patients. Recently, it has been proposed that macrophage inflammatory protein-1alpha (MIP-1alpha) is the clinical hallmark of hypercalcemia in ATL. In this study, we investigated the effect of extracellular calcium on MIP-1alpha secretion in ATL cells and the role of Ca(2+)/calmodulin (CaM)-dependent protein kinase (CaM-K) cascade in transcriptional activation of MIP-1alpha.


METHODS
MIP-1alpha protein levels in the culture supernatant collected from ATL cells were measured by enzyme-linked immunosorbent assay. Reporter plasmid containing the MIP-1alpha promoter was transfected to ATL cells, and the promoter activity was measured by luciferase assay.


RESULTS
The addition of calcium to the culture medium enhanced the secretion of MIP-1alpha from ATL cells, which was inhibited by the CaM-KK inhibitor. The transfection of CaM-KIV stimulated MIP-1alpha promoter activity, and the upstream kinase CaM-KK enhanced the stimulatory effect of CaM-KIV on the promoter activity. Mutation in the cyclic adenosine 5' monophosphate response element (CRE) within the MIP-1alpha promoter significantly reduced the effect of CaM-KIV, and CRE mutant promoter activity was not significantly enhanced by the addition of calcium to the culture medium as compared to wild-type promoter activity.


CONCLUSIONS
Hypercalcemia enhances MIP-1alpha secretion in ATL cells, and this mechanism requires the involvement of CaM-KK/CaM-KIV cascade through the CRE. These findings raise a possibility that the inhibitory effect of CaM-KK/CaM-KIV cascade may be a potential therapeutic target for ATL.
Matsumoto
Kensuke
K
Division of Endocrinology, Metabolism and Hematology, Department of Internal Medicine, Faculty of Medicine, Kagawa University, Kagawa, Japan. matsumot@med.kagawa-u.ac.jp
Murao
Koji
K
Imachi
Hitomi
H
Nishiuchi
Takamasa
T
Cao
Wenming
W
Yu
Xiao
X
Li
Junhua
J
Ahmed
Rania A M
RA
Iwama
Hisakazu
H
Kobayashi
Ryoji
R
Tokumitsu
Hiroshi
H
Ishida
Toshihiko
T
D001562:Benzimidazoles / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology; D054737:Calcium-Calmodulin-Dependent Protein Kinase Kinase / Q000037:antagonists & inhibitors; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D045744:Cell Line, Tumor; D054405:Chemokine CCL3 / Q000235:genetics / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015973:Gene Expression Regulation, Leukemic / Q000187:drug effects*; D006801:Humans; D007546:Isoquinolines / Q000494:pharmacology; D015458:Leukemia, T-Cell / Q000188:drug therapy / Q000378:metabolism*; D053644:Naphthalimides / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D011401:Promoter Regions, Genetic; D015398:Signal Transduction / Q000187:drug effects*
D001562:Benzimidazoles; D054405:Chemokine CCL3; D004791:Enzyme Inhibitors; D007546:Isoquinolines; D053644:Naphthalimides; C458525:STO 609; D054737:Calcium-Calmodulin-Dependent Protein Kinase Kinase; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D002118:Calcium