Malignant transformation induced by 7,12‐dimethylbenz(a)anthracene in rat embryo cells infected with rauscher leukemia virus

Abstract

Abstract This report describes morphological transformations observed approximately 6 weeks after treatment of Rauscher leukemia virus (RLV) infected rat embryo (RE) cells with various levels of 7,12‐Dimethylbenz(a)‐anthracene (DMBA) for 7 days. Uninfected cells treated with DMBA and RLV‐infected RE cells untreated with DMBA failed to show any evidence of transformation. When stained with Giemsa, the foci of transformed cells consisted of randomly oriented criss‐crossing spindle‐shaped cells, having much more rapid replication rates than the untreated and untransformed RE cells. The transformed cells were more resistant to the toxicity of DMBA than were the untransformed RE cells. Local subcutaneous sarcomas were produced when the transformed cells were transplanted into newborn rats, whereas the infected or DMBA‐treated untransformed cells produced no tumors. Cells derived from the tumors, when re‐established in tissue culture, like the tumor tissue itself contained group‐specific (GS) complement‐fixing antigens characteristic of the murine leukemia‐sarcoma virus complex and the C‐type RNA particles. These results, which showed that both chemical and virus were required for transformation, suggest that the C‐type RNA viral genome of RLV provided specific oncogene information for the malignant transformation.