Expression of the myc cellular proto-oncogene in human thyroid tissue.
The expression of cellular oncogenes was examined in human thyroid tissue. Four thyroid adenomas and three thyroid carcinomas expressed c-myc oncogene mRNA transcripts, which were not expressed in normal thyroid tissues. Agarose gel electrophoresis of poly(A) RNA extracts of adenoma tissues followed by hybridization with v-myc DNA yielded two distinct c-myc mRNA species [2.1 and 4.0 kilobases (kb)]. Thyroid cancer tissue poly(A) RNA revealed a predominant larger c-myc mRNA species (approximately 6 kb) and a smaller 2.1-kb species. After enzymatic dispersion of thyroid adenoma cells, cytoplasmic dot blot hybridization of immobilized thyroid adenoma RNA extracts with the v-myc cDNA probe showed stimulation of c-myc mRNA expression by TSH in a dose- and time-dependent manner. After 72-h pretreatment with serum-free medium, the quiescent adenoma cells yielded a negligible hybridization signal which was stimulated by TSH (10 mU/ml) after 6 h of treatment. Although normal cultured thyroid cells did not contain detectable c-myc mRNA, TSH also stimulated the myc protooncogene expression in a time-dependent manner in normal thyroid cells. These results demonstrate the expression of c-myc mRNA in human thyroid tumors and the in vitro induction of c-myc mRNA in both normal and adenoma thyroid cell cultures by TSH.
D000231:Adenocarcinoma, Papillary / Q000235:genetics; D000236:Adenoma / Q000235:genetics; D002478:Cells, Cultured; D005786:Gene Expression Regulation; D006801:Humans; D009693:Nucleic Acid Hybridization; D009857:Oncogenes / Q000187:drug effects; D000090063:Proto-Oncogene Mas; D011519:Proto-Oncogenes / Q000187:drug effects; D012333:RNA, Messenger / Q000378:metabolism; D013961:Thyroid Gland / Q000378:metabolism*; D013964:Thyroid Neoplasms / Q000235:genetics; D013972:Thyrotropin / Q000494:pharmacology
C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; D012333:RNA, Messenger; D013972:Thyrotropin