N,N-DIMETHYLFORMAMIDE-INDUCED MORPHOLOGICAL-DIFFERENTIATION AND REDUCTION OF TUMORIGENICITY IN CULTURED MOUSE RHABDOMYOSARCOMA CELLS

Abstract

N,N-Dimethylformamide treatment of cell cultures established from a transplantable murine rhabdomyosarcoma induced morphological differentiation and a marked reduction in the tumorigenicity of the sarcoma cells. Fourteen of 17 CE/J mice receiving injections of inducer treated cells did not develop tumors after 6 mo., whereas all 21 mice receiving inocula of untreated sarcoma cells died of disease between 11 and 32 days. The drug treated cells did not grow in soft agar. Untreated tumor cells grew in the semisolid medium. The untreated tumor cells showed a reduced serum requirement and had a higher saturation density compared to drug treated cells. The reduction in tumorigenicity of N,N-dimethylformamide treated cells correlates with certain in vitro growth properties that are more characteristic of normal, mesenchymally derived cells than sarcoma cells.