Expression of insulin-like growth factor II (IGF-II) in human primary liver cancer: mRNA and protein analysis.
Insulin-like growth factor II (IGF-II) is a polypeptide growth factor thought to be involved in fetal tissue development. We previously showed an increased expression of IGF-II mRNA in human primary liver cancer. The present investigation was undertaken to characterize the overexpressed IGF-II transcripts and to determine whether they are translated into protein. Two cDNAs with distinct 5' untranslated regions, corresponding to IGF-II transcripts expressed in fetal liver, were isolated from a primary liver cancer. Complete nucleotide sequence analysis showed an identical open reading frame of 540 bp, encoding a predicted polypeptide identical to the IGF-II isolated from serum. An increased synthesis of IGF-II protein was demonstrated by a protein-binding assay in tumorous liver samples, the highest levels being found in primary liver cancers with the highest IGF-II steady state level. By contrast, serum IGF-II content was low in most of primary liver cancer cases analyzed. Altogether, the results indicate reexpression of IGF-II both at the mRNA and protein levels in primary liver cancer. This finding is consistent with IGF-II being a marker of liver cell differentiation. In addition, this growth factor might be involved in liver cancer progression by an autocrine and/or paracrine mechanism.
Cariani
E
E
INSERM U75, C.H.U. Necker, Paris, France.
Seurin
D
D
Lasserre
C
C
Franco
D
D
Binoux
M
M
Brechot
C
C
D002759:Adenoma, Bile Duct / Q000235:genetics* / Q000378:metabolism; D000328:Adult; D001483:Base Sequence; D006528:Carcinoma, Hepatocellular / Q000235:genetics* / Q000378:metabolism; D002874:Chromosome Mapping; D004273:DNA, Neoplasm / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D005091:Exons; D005333:Fetus / Q000378:metabolism; D015870:Gene Expression; D006801:Humans; D007335:Insulin-Like Growth Factor II / Q000235:genetics* / Q000378:metabolism; D008113:Liver Neoplasms / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic / Q000235:genetics
D004273:DNA, Neoplasm; D012333:RNA, Messenger; D007335:Insulin-Like Growth Factor II