Establishment and characterization of cell lines derived from a human osteosarcoma.

Continuously growing cell lines have been established in vitro from a human osteosarcoma after transplantation into athymic nude mice. These cell lines grew as an adherent monolayer and consisted of various types of cells. Twelve clones were colonially isolated from a cell line, HuO-3N1, and subdivided into three groups depending on the morphologic features. The cells of HuO-3N1 and its clones had alkaline phosphatase (ALP)-positive granules in the cytoplasm. Cytogenetic studies showed that these cell lines were human aneuploid lines. A tumor was produced by injection of HuO-3N1 cells into an athymic nude mouse. ALP activity increased in a clonal cell line, HuO-3N1 cl-2, when cells were treated with 1,25-dihydroxy-vitamin D3. The proliferation of cells was inhibited when the cells were cultured in a medium supplemented with L-homoarginine, which is an inhibitor of bone and liver-specific ALP. This cell line has an osteoblastic phenotype and provides a useful model for studies of human osteosarcoma and phenotypical expression of human osteoblastic cells.