Oncogenic transformation of rat lung epithelioid cells by SV 40 DNA and restriction enzyme fragments

Rat epithelioid lung cells were transformed with various preparations of SV40 DNA using the Ca2+-precipitation technique. The amount of SV40 genetic information integrated into transformed clones was evaluated by DNA-DNA renaturation kinetics. The growth properties on plastic and in soft-agar were examined, as well as the ability to induce tumors in syngeneic new-born animals or in adult nude mice. One particular transformed line, which had received the HpaII/BamHI A (59 per cent) fragment, was found to contain about 3 integrated copies of this fragment per cell and no significant amount of the HpaII/BamHI B (41 per cent) fragment. This line which grew to high saturation densities and efficiently formed clones in low serum on plastic, produced tumors in both syngeneic rats and nude mice. Thus the HpaII/BamHI A fragment, which mainly includes early viral information, was sufficient to impart these properties to rat epithelioid lung cells.