Expression of cytokeratin 19 in human hepatocellular carcinoma cell lines.
It has been reported that the cytokeratin 19 (CK19) fragment, CYFRA 21-1, is increased in sera of some hepatocellular carcinoma patients. We hypothesized that CYFRA 21-1 might be released directly from hepatocellular carcinoma. To investigate this mechanism, we evaluated expression of CK19 in 8 human cell lines by immunoradiometric assay, Western blotting, immunohistochemistry, and reverse transcriptase-polymerase chain reaction in Chang liver cells, 2 cholangiocarcinoma cell lines, and 5 hepatocellular carcinoma cell lines. Three of 5 hepatocellular carcinoma cell lines released CYFRA 21-1, synthesized CK19 protein and expressed mRNA for CK19, as observed in 2 cholangiocarcinoma cell lines. In contrast, there was no expression of CK19 in Chang liver cells or 2 of 5 hepatocellular carcinoma cell lines. Analysis of genomic DNA for CK19 demonstrated that exon 1 was not amplified in the 3 cell lines not expressing CK19. However, there were no point mutations within exon 1 and the promoter region of CK19 in hepatocellular carcinoma cell lines. Our present study demonstrates that: i) the expression of CK19 was evident in some human hepatocellular carcinoma cell lines, and ii) the expression of mRNA for CK19 was related to the release of CYFRA 21-1. These results partially clarify the mechanism by which some hepatocellular carcinoma cell lines produce CK19 and others do not.
Wu
Fei
F
Third Department of Internal Medicine, Kagawa Medical University, Kagawa, Japan.
Nishioka
Mikio
M
Fujita
Jiro
J
Murota
Masayuki
M
Ohtsuki
Yuji
Y
Ishida
Toshihiko
T
Kuriyama
Shigeki
S
D000951:Antigens, Neoplasm / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D001650:Bile Duct Neoplasms / Q000235:genetics / Q000378:metabolism*; D015153:Blotting, Western; D006528:Carcinoma, Hepatocellular / Q000235:genetics / Q000378:metabolism*; D018281:Cholangiocarcinoma / Q000235:genetics / Q000378:metabolism*; D017931:DNA Primers; D004273:DNA, Neoplasm / Q000032:analysis; D015870:Gene Expression; D006801:Humans; D007124:Immunoenzyme Techniques; D015592:Immunoradiometric Assay; D053539:Keratin-19; D007633:Keratins / Q000235:genetics / Q000378:metabolism*; D008113:Liver Neoplasms / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014407:Tumor Cells, Cultured
D000951:Antigens, Neoplasm; D017931:DNA Primers; D004273:DNA, Neoplasm; D053539:Keratin-19; D012333:RNA, Messenger; C102012:antigen CYFRA21.1; D007633:Keratins