MORPHOLOGICAL AND BIOLOGICAL CHANGES OF A HEPATOCELLULAR-CARCINOMA CELL-LINE CULTURED IN A 3-DIMENSIONAL MATRIX OF COLLAGEN

A human hepatocellular carcinoma (HCC) cell line, KIM-1, was cultured in three different concentrations (0.1, 0.2 and 0.3%) of type-I collagen gel matrix and its morphologic features, growth kinetics and alpha-fetoprotein and albumin productions were compared with each other or with those of cells growing on a plastic dish. KIM-1 cells in any concentration of collagen gel matrix formed various sized three-dimensional colonies with compact to trabecular cell arrangement. Larger colonies with a more definitive trabecular cell arrangement, resembling the in vivo structure of HCC, tended to form in the collagen gel matrix of a low concentration. The prolongation of doubling time was identified as the collagen concentration in the gel became higher. The cells on a plastic dish proliferated in a monolayered sheet with a shorter doubling time than others. Ultrastructurally, the cells in collagen gel matrix have more distinct cell membranes, junctional complexes and bile canaliculus-like structures, and less cytoskeletons than those on plastic dishes, similar to those in vivo. The productions of alpha-fetoprotein per 10(4) cells and albumin per 10(5) cells were much higher in the collagen gel matrix culture than on a plastic dish in a stationary phase. These data suggest that collagen gel matrix culture is suitable to monitor the morphologic features and protein production of the tumor cells in similar conditions to those in vivo, and that the three-dimensional presence of an extracellular matrix is important in cellular proliferation and differentiation.