Uncoupling of growth inhibition and differentiation in dexamethasonetreated human rhabdomyosarcoma cells

C. De Giovanni, P. L. Lollini, R. Dolcetti, L. Landuzzi, G. Nicoletti, E. D'Andrea, K. Scotland, P. Nanni

Research output: Contribution to journalArticlepeer-review


The effects of dexamethasone, a synthetic glucocorticoid, and of N,N-dimethylformamide on in vitro growth and differentiation and on proto-oncogene expression of human rhabdomyosarcoma cells were studied. RD/ 18 clone cells (derived from the embryonal rhabdomyosarcoma cell line RD) treated with 100 nM dexamethasone showed an almost complete block of differentiation: about 5% myosin-positive cells were observed after 2 weeks of culture in dexamethasone-supplemented differentiation medium, compared to 20% of untreated cultures. Dexamethasone also induced a 20-30% growth inhibition and a more flattened morphology. The treatment with N,N-dimethylformamide induced a significantly increased proportion of myosin-positive cells (reaching about 30%) and a 40% growth inhibition. Induction of differentiation inversely correlated with the levels of c-myc proto-oncogene expression: after a 2 week culture dexamethasone-treated cells showed the highest c-myc expression and N,N-dimethylformamidetreated cells the lowest. Culture conditions per se down-modulated c-erbBI and up-regulated c-jun expression, with no relationship to the differentiation pattern. Other proto-oncogene' were not expressed (c-sis, N-myc, c-mos, c-myb) or were not modulated (c-fos, c-raf). Therefore dexamethasone and N,N-dimethylformamide, both causing a decreased growth rate, showed opposing actions on myogenic differentiation and on c-myc proto-oncogene expression of human rhabdomyosarcoma cells.

Original languageEnglish
Pages (from-to)674-679
Number of pages6
JournalBritish Journal of Cancer
Issue number4
Publication statusPublished - Apr 1993

ASJC Scopus subject areas

  • Oncology
  • Cancer Research


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