[The expression of osteoblastic features in a SV40 large T antigen immortalized mouse calvarial cell line]

A new cell line (VMCs) was established from the mouse calvarial cells transfected with the plasmid (pMT1-neo) containing a SV40 large T antigen gene and neomycin-resistance gene. The VMCs cell has been subcultured weekly for over 100 passages at the ratio of 1:20-1:60. Their population doubling time was about 15 hours. The VMCs cell seemed to be fibroblast-like monomorphic cells by a phase-contrast microscope. The cells were examined and characterized as osteoblastic features by alkaline phosphatase activity, bone formation in diffusion chamber and the expression of mRNAs of type I collagen and osteopontin. The features were as follows: 1. Alkaline phosphatase activity of the VMCs cell was low in growth phase but was increased by the treatment with retinoic acid. 2. Differentiation of the VMCs cell was examined by diffusion chamber implanted intraperitoneally into Balb/c mouse. Implants were sectioned and stained with hematoxylin-eosin, alizarin red S, von Kóssa, alcian blue or Azan. In the chambers formation of mineralized matrices and collagenous fibrils were observed. 3. Northern analysis demonstrated the expression of type I collagen and osteopontin mRNAs. Osteopontin mRNA was increased by the treatment with 1 alpha,25(OH)2D3 or retinoic acid. These results suggest that the VMCs cell have some properties of the osteoblast and consider to be useful for the study of bone formation and the biocompatibility test for the dental or medical materials.