Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0035412 (rhabdomyosarcoma)
 6,156 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Three clonal rat rhabdomyosarcoma subpopulations (A, B, C) with a block of differentiation at different levels of rhabdomyogenesis were exposed to the differentiation inducers retinoic acid (RA), N-methylformamide (NMF) and sodium butyrate (NaBut). Since an increased expression of c-raf and c-fos had recently been demonstrated for subpopulation C after exposure to RA and NMF (1), the mRNA expression of c-raf, c-fos and retinoic acid receptor (RAR) alpha, beta and gamma was compared in all three subpopulations. After exposure to RA, NMF or NaBut, subpopulation C exhibited a significant (p = 0.0001) increase in creatine kinase (CK) activity and in morphological differentiation. In subpopulation B, the response was confined to a significant (p = 0.0001) increase in creatine kinase activity, whereas subpopulation A proved to be differentiation-refractory. On the molecular level, a uniform increase in c-raf expression became evident in all three subpopulations after 6 to 12 hours, persisting at an elevated level throughout the observation period of 120 hours. In contrast, the pattern of c-fos expression observed after exposure to RA, NMF or NaBut was heterogeneous. Expression of RAR alpha and gamma was detected in all subpopulations, whereas RAR beta mRNA was not expressed. Summarizing our results, the uniform pattern of c-raf expression might suggest a participation of c-raf in differentiation signal transduction. Since the three subpopulations differ markedly in their degree of differentiation, the block of differentiation characteristic for each subpopulation supposedly becomes effective only after the action of the c-raf gene product.
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PMID:Increase in proto-oncogene raf expression precedes differentiation induction in different clonal rhabdomyosarcoma subpopulations. 131 93

BA-HAN-IC is a clonal rat rhabdomyosarcoma cell line consisting of proliferating mononuclear tumor cells, some of which spontaneously fuse to form terminally differentiated post-mitotic myotubes. Exposure of BA-HAN-IC cells to retinoic acid (RA) or N-methylformamide (NMF) resulted in a significant inhibition of proliferation (p less than 0.001) and in cellular differentiation, as evidenced by a significant increase in the creatine kinase (CK) activity (p less than 0.05) and the number of terminally differentiated post-mitotic myotubes (p less than 0.001). Furthermore, between 5% (NMF) and 30% (RA) of the mononuclear tumor cells exhibited ultrastructural features of rhabdomyogenic differentiation, not observed in their mononuclear counterparts under standard growth conditions. Although BA-HAN-IC cells responded to both inducers of differentiation, differences in time course and magnitude of both increase of differentiation and growth inhibition were observed. These effects of RA and NMF were preceded by a marked enhancement of c-raf expression which became evident 6 and 12 hr after exposure to RA and NMF, respectively, and which persisted throughout the observation period of 5 days. Furthermore, a transient expression of c-fos could be observed 15 and 30 min after exposure to RA. Our results suggest that c-raf expression might be implicated in the differentiation process of BA-HAN-IC tumor cells.
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PMID:Enhanced expression of the proto-oncogenes fos and raf in the rhabdomyosarcoma cell line BA-HAN-1C after differentiation induction with retinoic acid and N-methylformamide. 210 33