COLLAGEN AND ELASTIN SYNTHESIS BY DESMOID TUMOR IN-VITRO

In order to characterize human desmoid tumors in vitro, the production of collagen and elastin and the expression of collagen types alpha 1( I), alpha 1(III) and transforming growth factor (TGF)-beta 1 mRNA were investigated in six desmoid tumors; five derived from familial adenom atous polyposis patients and one from a sporadic case, The proportion of collagen production to total protein production was determined by 3 H-imino acid incorporation, an indicator of collagen synthesis, using high-performance liquid chromatography (HPLC), The proportion of colla gen production to total protein production was much higher in all six desmoid tumors compared with human skin fibroblasts (HSF). Quantitativ ely, the rate of elastin synthesis in desmoid tumor cells monitored by valine-proline peptide was also significantly higher than in HSF. Pro -alpha 1(I) collagen mRNA was highly expressed in both desmoid tumors and HSF at approximately the same level, whereas pro-alpha 1(III) coll agen mRNA was more abundant in some of the desmoid tumors than the nor mal skin fibroblastic cell lines, Tumor growth factor-beta 1 mRNA, whi ch is believed to stimulate collagen synthesis, was expressed in both desmoid tumors and HSF to the same extent, These results demonstrate t he increased formation of collagen and elastin in desmoid tumors in vi tro and suggest that the increased synthesis of elastin rather than of collagen and TGF-beta 1 may be involved in increased fibrogenesis by desmoid tumors.