title: Expression of TGF-beta 1 protein and mRNA and the effect on the tissue remodeling in laryngeal carcinomas.
abstract: TGF-beta is one of the most effective suppressors of cell proliferation and acts as a potent inducer of matrix formation by promoting the neosynthesis of the extracellular matrix and inhibiting the synthesis of matrix degrading enzymes. In this study we analysed the expression of TGF-beta 1 protein and mRNA in normal laryngeal mucosa and in invasive laryngeal carcinomas, to find out any differences in the amount of expressed TGF-beta 1 and to identify the cells which are actively involved in the synthesis of TGF-beta 1. In addition, we analysed the biological effect of TGF-beta 1 on the rate of tumor cell proliferation and the amount of neosynthesis of the extracellular matrix. The study comprised a series of 24 laryngeal squamous cell carcinomas (SCC) of different degree of tumor cell differentiation and 10 cases of normal laryngeal mucosa, which was immunhistochemically analyzed using antibodies against TGF-beta 1, the cell proliferation antigen Ki-67 (Mib-1 antibody) and major interstitial collagen types (III, V, VI) and tenascin. The TGF-beta 1-mRNA was identified by non-radioactive in-situ hybridization using a 360bp cDNA-clone for TGF-beta 1. All immunostainings and the in-situ hybridization were quantitatively evaluated by morphometric analysis and subjected to a statistical evaluation. In the normal laryngeal mucosa we found TGF-beta 1 protein mainly in the suprabasal epithelial cell layer and in some stroma cells below the epithelium. The mRNA of TGF-beta 1 was located in the basal cell layer of the normal mucosa as well as in the stroma cells next to the squamous cell epithelial. All cases of invasive carcinoma analysed showed a positive cytoplasmatic staining for TGF-beta 1 in the tumor cells as well as in stroma cells with a significantly more intense staining in the tumor cells than in the stroma cells. The in-situ hybridisation for TGF-beta 1-mRNA provided also positively stained tumor as well as stroma cells. Again, the amount of positively labeled tumor cells outnumbered the amount of stained stroma cells. In addition, we found a dramatic increase of the proliferation index in the invasive laryngeal carcinomas which was correlated with the amount of TGF-beta 1 expression. The collagens III, V and VI as well as tenascin were found strongly in the invasive carcinomas when compared to the normal mucosa, with statistically positive correlation. In conclusion, we found that invasive tumor growth of the larynx is associated with an increase of the TGF-beta 1 protein and mRNA expression. The synthesis of TGF-beta 1 is mainly performed by the tumor cells, but also to a lesser extent by the stroma cells. We provide evidence, that the TGF-beta 1 is biologically active on the neofomation of extracellular matrix components. In contrast the lack of a suppressive effect on the proliferative capacity of the tumor cells, indicates a "dissociation" of the TGF-beta effect in SCCs. A possible reason for this dissociation may lie in a partial dysfunction of the TGF-beta receptors of the tumor cells or in defects of the intracellular signaling pathways.
authors.affiliation: Dept. of Otolaryngology, Head and Neck Surgery, University of Munich, Grosshadern Medical Center, Germany.
authors.forename: H
authors.initials: H
authors.lastname: Hagedorn
authors.forename: U
authors.initials: U
authors.lastname: Sauer
authors.forename: E
authors.initials: E
authors.lastname: Schleicher
authors.forename: A
authors.initials: A
authors.lastname: Nerlich
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D034961:Antigens, Nuclear; D002277:Carcinoma / Q000378:metabolism / Q000473:pathology; D002455:Cell Division / Q000187:drug effects; D003094:Collagen / Q000378:metabolism / Q000494:pharmacology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D019394:Ki-67 Antigen; D007822:Laryngeal Neoplasms / Q000378:metabolism* / Q000473:pathology; D007830:Larynx / Q000378:metabolism / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009092:Mucous Membrane / Q000378:metabolism / Q000473:pathology; D009687:Nuclear Proteins / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D019063:Tenascin / Q000494:pharmacology; D016212:Transforming Growth Factor beta / Q000096:biosynthesis*
chemical_list: D034961:Antigens, Nuclear; D019394:Ki-67 Antigen; D009687:Nuclear Proteins; D012333:RNA, Messenger; D019063:Tenascin; D016212:Transforming Growth Factor beta; D003094:Collagen