INHERITABLE PHENOTYPIC NORMALIZATION OF R ODENT CELLS TRANSFORMED WITH E1 ONCOGENES OF SIMIAN ADENOVIRUS SA7 BY SINGLE-STRAND OLIGONUCLEOTIDES THAT ARE COMPLEMENTARY TO THE LONG REGION OF THE INTEGRATED ONCOGENES

G11 mouse cells and SH2 rat cells transformed with simian adenovirus S A7 DNA showed inheritable oncogen-specific phenotypic normalization wh en treated with sense and antisense oligonucleotides complementary to long RNA sequences, plus or minus strands of the integrated adenovirus oncogenes E1A and E1B. Transitory treatment of the cells with the oli gonucleotides in the absence of serum was shown to cause the appearanc e of normalized cell lines with fibroblastlike morphology, slower cell proliferation, and lack of ability to form colonies in soft agar. Pro liferative activity and adhesion of the normalized cells that establis hed cell lines were found to depend on the concentration of growth fac tors in the cultural medium. In some of the cell lines, an inhibition of transcription of the E1 oncogenes was observed. The normalization a lso produced cells that divided 2 - 5 times and died and cells that re verted to a transformed phenotype in 2 - 10 days. The latter appeared predominantly upon the action of the antisense oligonucleotides.