Fibroblasts stimulate human ovarian cancer cell invasion and expression of 72-kDa gelatinase A (MMP-2).

Objective: The host-tumor interactions and tumor stroma may participate in the regulation of invasive behavior of tumor cells. In order to better understand the human ovarian cancer invasion we explored the possibility that normal fibroblasts could participate in the control of the spread of human ovarian cancer.

Results: A 3.5-fold increase (from 2.83 +/- 0.97 to 10.2 +/- 3.43%) in human ovarian cancer cell (Ovcar-3) invasion through a reconstituted basement membrane was noted when normal fibroblasts (CRL 1295) were added to the invasion chambers in conjunction with tumor cells. Conditioned medium from either fibroblasts or Ovcar-3 also enhanced the in vitro invasion of Ovcar-3 by 2- to 2.5-fold (from 2.83 +/- 0.97 to 5.71 +/- 3.5 and to 7.15 +/- 1.2%, respectively) compared to nonstimulated control cells. Zymographic analysis and assays of mRNA for the 72-kDa matrix metalloproteinase (MMP-2) showed that Ovcar-3 cells alone produced very low levels of MMP-2; the expression of this gelatinase was detectable in zymography only with stimulation by incubation of these cells with conditioned media from either fibroblasts or ovarian cancer cells themselves. Interestingly, MMP-2 activity was increased also in fibroblasts when using either ovarian cancer cell-conditioned (to 178 +/- 67%) or fibroblast-conditioned medium (to 215 +/- 61%) and the gene expression for MMP-2 was similarly increased in both fibroblasts and Ovcar-3 cells when using either fibroblast-conditioned medium or ovarian cancer cell-conditioned medium from 1.00 +/- 0.25 to 2.20 +/- 0.50 and 1.86 +/- 0.10 in fibroblasts and from 1.00 +/- 0.26 to 1.60 +/- 0.34 and 2.15 +/- 0.30 in Ovcar-3 cells, respectively.

Conclusions: These results show that interplay between tumor cells and normal cells in the control of invasion and secretion of proteolytic enzymes may involve not only paracrine but also autocrine elements. Thus, such interactions are possible and may play an important role in the spread of cancer.