Expression of type C RNA virus particles in 224Ra-induced osteosarcomas

Abstract

The experiments reported are part of a program to evaluate the role of RNA tumor viruses in radionuclide-induced osteosarcomas of mice. The expression of type C RNA virus particles was investigated in 224Ra-induced primary osteosarcomas as well as in transplanted tumors and cell cultures derived from the primary osteosarcomas. Virus particle expression could be detected in primary osteosarcomas by electron microscopy as intracisternal type A and type C particles and by the simultaneous detection test as a particulate structure containing a high molecular weight RNA associated with a reverse transcriptase. The same viral markers were also detected in transplanted osteosarcomas. In contrast to tumors of inbred C3H x l0l/F1 mice, primary and transplanted osteosarcomas in random-bred NMRI mice did not show type C virus particles by electron microscopy nor viral parameters in the simultaneous detection test. In vitro cultivated osteosarcomas from NMRI mice also produced virus particles. The virus particles possessed the typical properties of rna tumor viruses like type c morphology, a density in sucrose of 1,16-1,18 g/cm3 and a reverse transcriptase associated with a high molecular weight RNA of 60-70 S. Thus far, no oncogenic activity of the virus particles associated with the tumors or cell cultures could be detected.