Biosynthesis of various types of collagen by human hepatoma cells in vitro

Extracellular matrix in hepatoblastoma: an immunohistochemical investigation

Eleven hepatoblastomas of various subtypes and normal liver tissue were investigated with antibodies against collagen types I-VI, laminin, fibronectin and endothelial and macrophage-associated antigens. Epithelial hepatoblastoma cells, unlike non-neoplastic hepatocytes, exhibited intracellular immunoreactivity for various extracellular matrix proteins (depending on the subtype: laminin, fibronectin and collagen types III, IV and V). The intracellular expression of extracellular matrix proteins by the tumour cells increased from the fetal subtype, through the embryonal subtype, to the small cell subtype. The epithelial tumours exhibited sinusoid-like blood vessels in numbers that varied according to the subtype. These contained Kupffer cells and exhibited greater amounts of the basement membrane components collagen type IV and laminin in the perisinusoidal space than those in the normal liver. The small cell hepatoblastoma exhibited smaller numbers of sinusoids, pronounced intracellular expression of extracellular matrix proteins and large numbers of fibres immunoreactive for collagen type III. In the mixed hepatoblastomas, the extracellular matrix of the osteoid was most strongly immunoreactive for collagen type I and that of the spindle cell areas for collagen type III.

Further cellular investigation of the human hepatoblastoma-derived cell line HepG2: morphology and immunocytochemical studies of hepatic-secreted proteins

The hepatoblastoma cell line HepG2 has been a matter of many investigations; most of them include biochemical studies of lipoprotein and other hepatic protein metabolism. However, the accurate cellular features of these cells have not been emphasized. We studied the cellular histologic, histochemical, and ultrastructural characteristics of this cell line. In addition, we investigated by immunoenzymatic methods the cellular biosynthesis of several proteins: apolipoproteins-AI, -B, -D, and -E, albumin, alpha-fetoprotein, transferrin, alpha-1-antitrypsin, C-reactive protein, fibronectin, and collagens I, III and IV. The rates of accumulation, in the medium of HepG2 cells, of albumin, alpha-1-antitrypsin, transferrin, and alpha-fetoprotein were 13.2 +/- 1.9; 4.9 +/- 1.5; 3.2 +/- 0.4; and 10.7 +/- 1.7 micrograms/10(6) cells/24 h, respectively. Our results show that HepG2 cells exhibited most cellular features of normal human hepatocytes. Bile canaliculi as well as Golgi apparatus complexes were particularly developed. Except for the C-reactive protein, HepG2 cells have all retained the ability to synthesize hepatic proteins but with some variable intensity from cell to cell. This hepatoblastoma cell line seems to represent a useful tool in the understanding of hepatic protein biosynthesis, particularly for the investigation on the secretory pathway of plasma proteins.

A new human pleomorphic hepatocellular carcinoma cell line, KYN-2

A new human hepatocellular carcinoma (HCC) cell line, KYN-2, has been established from a surgical specimen obtained from a 52-year-old Japanese male HCC patient. The originally resected HCC was classified as pleomorphic HCC corresponding to Edmondson-Steiner's grade III with a thick trabecular to solid arrangement. The cell line has been maintained for 17 months through 35 passages. Morphologically, the KYN-2 cells have retained the characteristics of the original HCC, being pleomorphic and composed of various types such as cells with relatively small, polygonal, eosinophilic cytoplasm and oval-shaped nuclei with a marked tendency to pile up, flat cells with abundant clear cytoplasm and oval-shaped nuclei, and many multinucleated giant cells, proliferating in a pavement-like cell arrangement. Some junctional complexes and a number of microvilli are evident between the cells by electron microscopy. Functionally, these cells were found to secrete albumin, alpha 1-acid glycoprotein, alpha 1-antitrypsin, ceruloplasmin, transferrin, complement C, fibrinogen, fibronectin, prothrombin, retinol-binding protein (serum type), alpha-fetoprotein (AFP), carcinoembryonic antigen (CEA), ferritin and beta 2-microglobulin in chemically defined medium (CDM). The secretion of AFP and CEA is apparently dependent upon culture medium and passage. The doubling time of cells growing in serum-containing medium at the 14th passage was 84 h, and those of cells in serum-containing medium, HB101 (serum-free medium) and CDM at late passage were 28, 68, and 42 h, respectively. Chromosome analysis revealed that the chromosome number ranged from 56 to 69 without a mode, and the presence of marker chromosomes. HB virus DNA sequence was not detected by hybridization analysis. The tumorigenicity of KYN-2 cells was identified by development of tumors in nude mice after subcutaneous injection of the cells; the tumors showed an appearance basically similar to that of the original HCC. Thus, these findings suggest that the KYN-2 cell line is available as a new human HCC cell line and should be useful for various studies on HCC.