In vitro growth inhibition of ovarian cancer cells by decorin: Synergism of action between decorin and carboplatin

In vitro studies showed that decorin, a small proteoglycan that is a normal component of the cell matrix involved in tissue scaffolding, effectively i nhibited the growth of two ovarian cancer lines, SHOV3 and 2774. Using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay to measu re cell growth, IC(50)s for decorin ranged from 150 to 400 mu g/ml for the two cell lines, In contrast, the growth of tumor cells grown on an artifici al cell matrix (Matrigel) was unaffected By decorin treatment, perhaps beca use of the decorin being irreversibly bound by matrix-associated collagen. Decorin-induced inhibition of ovarian tumor cells appeared to be associated with the increased expression of the cyclin-dependent kinase inhibitor p21 (Waf1/Cip1). Up-regulation of p21 expression was shown by Western blot anal ysis in decorin-treated ovarian cancer cells. No decorin-induced up-regulat ion of c-myc was seen, although decorin was reported to activate the epider mal growth factor receptor. Decorin was also shown to synergize with carbop latin to inhibit the growth of ovarian tumor cells. Additional studies are warranted to determine the role of decorin in the treatment of ovarian canc er.