Minute virus of mice inhibits cell transformation by simian virus 40

Certain paroviruses have been reported to inhibit spontaneous or virus-induced tumorigenesis in rodents; the mechanisms of this antineoplastic activity is unknown. We have investigated the ability of the minute virus of mice (MVM), a non-defective paravirus, to interfere with the in vitro transformation of mouse cells by simian virus 40 (SV40). We used variants of BALB/c 3T3 cells, denoted PVR, selected for their resistance to the lytic effect of MVM. We report here that inoculation of SV40-infected PVR cells with MVM reduced dramatically the yield of transformed clones. Moreover, stable SV40 transformants of PVR cells lost up to 85% of their ability to grow in soft agar after MVM infection. Our results indicate that the antineoplastic effect of parvoviruses can be simulated in cell cultures and may involve a direct and selective toxic effect of these viruses on malignant cells or their precursors.SCOPUS: ar.j