Ephrin-A1 expression contributes to the malignant characteristics of {alpha}-fetoprotein producing hepatocellular carcinoma.
OBJECTIVE
alpha-Fetoprotein (AFP), a tumour marker for hepatocellular carcinoma (HCC), is associated with poor prognosis. Using cDNA microarray analysis, we previously found that ephrin-A1, an angiogenic factor, is the most differentially overexpressed gene in AFP producing hepatoma cell lines. In the present study, we investigated the significance of ephrin-A1 expression in HCC.


METHODS
We examined ephrin-A1 expression and its effect on cell proliferation and gene expression in five AFP producing hepatoma cell lines, three AFP negative hepatoma cell lines, and 20 human HCC specimens.


RESULTS
Ephrin-A1 expression levels were lowest in normal liver tissue, elevated in cirrhotic tissue, and further elevated in HCC specimens. Ephrin-A1 expression was strongly correlated with AFP expression (r = 0.866). We showed that ephrin-A1 induced expression of AFP. This finding implicates ephrin-A1 in the mechanism of AFP induction in HCC. Ephrin-A1 promoted the proliferation of ephrin-A1 underexpressing HLE cells, and an ephrin-A1 antisense oligonucleotide inhibited the proliferation of ephrin-A1 overexpressing Huh7 cells. Thus ephrin-A1 affects hepatoma cell growth. cDNA microarray analysis showed that ephrin-A1 induced expression of genes related to the cell cycle (p21), angiogenesis (angiopoietin 1 and thrombospondin 1), and cell-cell interactions (Rho, integrin, and matrix metalloproteinases) in cultured hepatoma cells. These ephrin-A1 induced genes are also activated in HCC tissues that overexpress AFP.


CONCLUSIONS
These findings suggest that the poor prognosis of patients with AFP producing HCC is partially caused by ephrin-A1 expression, which induces expression of genes related to tumour cell growth, angiogenesis, invasion, and metastasis.
Iida
H
H
Department of Cancer Gene Regulation, Kanazawa University Graduate School of Medical Science, 13-1 Takara-Machi, Kanazawa 920-8641, Japan.
Honda
M
M
Kawai
H F
HF
Yamashita
T
T
Shirota
Y
Y
Wang
B-C
BC
Miao
H
H
Kaneko
S
S
D006528:Carcinoma, Hepatocellular / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D018797:Cell Cycle Proteins / Q000378:metabolism; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D050759:Cyclin-Dependent Kinase Inhibitor p21; D018844:Cyclin-Dependent Kinases / Q000378:metabolism; D018076:DNA, Complementary / Q000032:analysis; D004305:Dose-Response Relationship, Drug; D036382:Ephrin-A1 / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D008113:Liver Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D020411:Oligonucleotide Array Sequence Analysis; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D011379:Prognosis; D012333:RNA, Messenger / Q000378:metabolism; D000509:alpha-Fetoproteins / Q000378:metabolism*
C493956:CDKN1A protein, human; D018797:Cell Cycle Proteins; D050759:Cyclin-Dependent Kinase Inhibitor p21; D018076:DNA, Complementary; D036382:Ephrin-A1; D016376:Oligonucleotides, Antisense; D012333:RNA, Messenger; D000509:alpha-Fetoproteins; D018844:Cyclin-Dependent Kinases