[Inhibition of PI3K/AKT signaling pathway promotes the nuclear translocation of B7-H4].
OBJECTIVE
To investigate the regulatory effect of phosphatidylinositol-3-kinase/protein kinase B (PI3K/AKT) signaling pathway on the subcellular distribution of negative co-stimulatory molecule B7-H4.


METHODS
The HEK293 cells transfected stably with B7-H4, named B7-H4/HEK293, were treated with the PI3K/AKT specific inhibitor LY294002 and/or the nuclear export inhibitor leptomycin B (LMB). The subcellular localization of B7-H4 in B7-H4/HEK293 was observed by immunofluorescence and confocal laser scanning microscopy (CLSM), and the expression levels of B7-H4 in membrane, cytoplasm and nuclear were detected by Western blotting.


RESULTS
CLSM showed that LY294002 effectively induced the nuclear translocation of B7-H4 when compared with vehicle group. When the B7-H4/HEK293 cells were treated with LY294002 and LMB, more B7-H4 was translocated into nuclear. Western blotting demonstrated that after the PI3K/AKT signal pathway was inhibited by LY294002 for 24 hours, the levels of B7-H4 in cell membrane and cytoplasm decreased significantly (P<0.05), while the expression in nuclear increased significantly (P<0.05).


CONCLUSIONS
The PI3K/AKT signal pathway might inhibit the nuclear translocation of B7-H4.
Department of Pharmacy, School of Pharmaceutical Science, School of Basic Medicine and Life Sciences, Medical College, Soochow University, Suzhou 215123, China.
Hui
H
Song
Department of Immunology, School of Basic Medicine and Life Sciences, Medical College, Soochow University, Suzhou 215123, China.
Wei
W
Xie
Department of Pharmacy, School of Pharmaceutical Science, School of Basic Medicine and Life Sciences, Medical College, Soochow University, Suzhou 215123, China.
Qihui
Q
Lian
Department of Pharmacy, School of Pharmaceutical Science, School of Basic Medicine and Life Sciences, Medical College, Soochow University, Suzhou 215123, China.
Minji
M
Chen
Department of Pharmacy, School of Pharmaceutical Science, School of Basic Medicine and Life Sciences, Medical College, Soochow University, Suzhou 215123, China.
Rong
R
Xu
Department of Pharmacy, School of Pharmaceutical Science, School of Basic Medicine and Life Sciences, Medical College, Soochow University, Suzhou 215123, China.
Shuang
S
Zeng
Department of Pharmacy, School of Pharmaceutical Science, School of Basic Medicine and Life Sciences, Medical College, Soochow University, Suzhou 215123, China.
Liang
L
Zhang
D021581:Active Transport, Cell Nucleus / Q000187:drug effects; D002867:Chromones / Q000494:pharmacology; D005231:Fatty Acids, Unsaturated / Q000494:pharmacology; D005455:Fluorescent Antibody Technique; D057809:HEK293 Cells; D006801:Humans; D009025:Morpholines / Q000494:pharmacology; D000081082:Phosphoinositide-3 Kinase Inhibitors; D021381:Protein Transport / Q000187:drug effects; D051057:Proto-Oncogene Proteins c-akt / Q000037:antagonists & inhibitors*; D015398:Signal Transduction / Q000187:drug effects*; D060907:V-Set Domain-Containing T-Cell Activation Inhibitor 1 / Q000378:metabolism*
D002867:Chromones; D005231:Fatty Acids, Unsaturated; D009025:Morpholines; D000081082:Phosphoinositide-3 Kinase Inhibitors; D060907:V-Set Domain-Containing T-Cell Activation Inhibitor 1; C475826:VTCN1 protein, human; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D051057:Proto-Oncogene Proteins c-akt; C038753:leptomycin B