Transfection of murine P19S18 embryonal carcinoma cells with the oncogene neu induces an epithelioid phenotype

. An embryonal carcinoma cell line, P19S18, was transfected with the rat oncogene neu to investigate the function of its protein product, p185*, in a multipotential cellular environment. Levels of message for p185* were determined by in situ hybridization analysis and two highly expressing clones, PnnA and PnnB, were isolated. As demonstrated by indirect immunofluorescence and immunoprecipitation, these neu‐transfected cells synthesized a full length rat p185*. The transfectants do not resemble typical embryonal carcinoma cells either before or after differentiation is induced by retinoic acid treatment. They are much larger, flatter, “epithelioid” cells. These cells have lost the expression of stage specific embryonic antigen‐1 (SSEA‐1), but do synthesize and assemble the basement membrane components laminin and fibronectin. These results suggest that expression of the neu oncogene in a multipotential cell line may induce the synthesis of proteins indicative of an epithelioid phenotype due to the presence of p185*.