Osteopontin regulation by protein kinase B (Akt) in HepG2 cells.
OBJECTIVE
The mechanism responsible for osteopontin regulation is not understood in HepG2 cells. The aim of this study was to investigate the relationship between protein kinase B (Akt), a key gene in PI3K signal transduction pathway, and osteopontin expression.


METHODS
HepG2 cells were transfected with constitutively active Akt and dominant negative Akt using lipofectin. The Akt transfection was confirmed by Western blot analysis. Osteopontin expression was detected by both Northern blot and Western blot.


RESULTS
Overexpression of exogenous Akt was detected in HepG2 cells by Western blot, indicating that HepG2 cells were successfully transfected with the Akt genes. In serum-free condition, the expression of osteopontin was either low or undetectable in HepG2 cells transfected with vector only, however, the expression increased after transfection of cells with constitutively active Akt. Osteopontin expression decreased when HepG2 cells were transfected with dominant negative Akt.


CONCLUSIONS
Protein kinase B (Akt) gene regulated osteopontin expression in RNA level and protein level, suggesting that osteopontin synthesis can be blocked by inactivation of the Akt gene. This leads to a potential means of intervention for the inhibition of metastases in liver cancer.
Zhang
G
G
Department of Gastroenterology, First Affiliated Hospital, Nanjing Medical University, China. zhhuang@njmu.edu.cn
Huang
Z
Z
Shi
R
R
Lin
Y
Y
Hao
B
B
D001483:Base Sequence; D006528:Carcinoma, Hepatocellular; D045744:Cell Line, Tumor; D017931:DNA Primers; D011905:Genes, ras; D006801:Humans; D008113:Liver Neoplasms; D053495:Osteopontin; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D015183:Restriction Mapping; D012795:Sialoglycoproteins / Q000235:genetics*; D015398:Signal Transduction / Q000502:physiology; D014162:Transfection
D017931:DNA Primers; D011994:Recombinant Proteins; C506895:SPP1 protein, human; D012795:Sialoglycoproteins; D053495:Osteopontin; D051057:Proto-Oncogene Proteins c-akt