The in vitro growth, heterotransplantation, and differentiation of a human rhabdomyosarcoma cell line.

A human rhabdomyosarcoma (RMS) cell line was established from a case of childhood small cell sarcoma, which in vivo showed no evidence of differentiation, but which demonstrated myogenic differentiation in tissue culture. In a serum-free culture medium, the tumor cells demonstrated continuous growth without ultrastructural or biochemical evidence of differentiation. Heterotransplanted RMS cells gave rise to tumors in nude mice which also showed no myogenic differentiation. However, RMS cells grown in the presence of either retinoic acid (5 microns), phorbol ester (1 nM), prostaglandin E1 (10 ng/ml), or 2% fetal calf serum gave rise to myotubes with a biochemical shift in the creatine kinase isoenzyme pattern from the embryonic to the mature skeletal muscle form. The karyotype of the RMS cells revealed a translocation of Chromosomes 2 and 13, which may represent a nonrandom aberration unique to this morphologic subtype. In addition, the RMS cells gave evidence for gene amplification in the form of double minute chromosomes. This human RMS cell line provides a valuable in vitro system for study of myogenesis and factors which induce differentiation.