Interaction of human malignant melanoma tumor spheroids with endothelium and reconstituted basement membrane: Modulation by RGDS

Abstract

Tumor-cell extravasation involves sequential adhesive interactions with vascular endothelium and the subendothelial basement membrane. We have established a 3-dimensional model in vitro to simulate these events and to elucidate targets of the anti-cell-adhesive synthetic peptide RGDS. Tumor spheroids of the melanoma cell line ST-ML-12 served as models of tumor-cell emboli and were transferred onto human umbilical vein endothelial cells. To imitate the vascular anatomy, the latter were grown on reconstituted basement membranes produced by dextran-stimulated bovine corneal endothelial cells. RGDS did not affect the homotypic aggregation of the tumor cells and only minimally inhibited the attachment of the spheroids to the reconstituted vessel. A short-term (20 min) inhibition of adhesion to denuded basement membranes was observed. The attachment was closely associated with damage to the endothelial cells by oxygen-derived free radicals. RGDS retarded endothelial injury for up to 3 hr. The most prominent effect was observed after penetration of the endothelium. RGDS suppressed the emigration of tumor cells from the attached tumor-cell cluster in a dose- and time-dependent fashion. After 12 hr, the inhibitory effect progressively declined. This was not due to loss of activity of the peptide, indicating a resistance mechanism in the melanoma cells. On purified components of the basement membrane, RGDS effectively inhibited the initial spheroid attachment to fibronectin and collagen IV but had no effect on attachment to laminin. By contrast, subsequent migration was significantly suppressed on all substrata. Our model permits the study of dynamic cell-cell and cell-extracellular-matrix interactions and indicates that RGDS might predominantly act on early tumor-cell locomotion after penetration of the endothelium.

Hypoxia-Induced Tumour Cell Migration in an in vivo Chicken Model

“…Ffrench-Constant and Hynes [43] showed that fibronectin may play a role in the migration of mesenchymal cells of the area vasculosa and endocardial cushion cells. The results presented by Offner et al [44] show that fibronectin is also important for the migration of malignant melanoma cells. Thus, over-expression of matrixdegrading enzymes and interactions with several components of the extracellular matrix by the glioma cells themselves or induced by hypoxia might contribute to the tumour cell spread presented here.…”

Lipoxygenase mediates invasion of intrametastatic lymphatic vessels and propagates lymph node metastasis of human mammary carcinoma xenografts in mouse

“…To gain insights into the mechanisms underlying lymphatic bulk invasion, we have adapted a reductionistic in vitro assay (25,26) that mimics some features of the in vivo situation. In this system, tumor cell spheroids corresponded to invasive tumor aggregates in vivo, and in lieu of intrametastatic lymphatic vessels, we used monolayers of dermal lymphatic endothelial cells.…”

“…We used an in vitro coculture system to analyze the mechanisms of tumor cell-mediated disruption of lymphatic vessels. This employed spheroids (25,26) of MCF7 mammary carcinoma cells to reproduce the clusters of cells seen in tumor emboli in vivo. MCF7 cell spheroids remained stable Table 1 Characterization of tumors and patients' outcome …”

“…Cell spheroids were prepared as described in preliminary experiments (25,26). briefly, MCF7 cells were grown in McCoy 5A medium containing 10% fetal calf serum and 1% penicillin/streptomycin (Gibco-brL; Invitrogen).…”

Human Peritoneal Mesothelial Cells Are More Potent Than Ovarian Cancer Cells in Producing Tumor Marker CA-125

“…Isolation of cells was carried out by a modified medium as the mesothelial cells (see above). method previously described elsewhere [21]. Briefly, small biopsies (approximately 3 cm 3 ) of omental tissue were rinsed Cancer Cells in phosphate-buffered saline (PBS), transferred to a 0.05% solution of collagenase I (Worthington, Boehringer-MannFor experiments, HPMCs and ovarian cancer cells were heim) and allowed to float for 1.5-2 hr at 37ЊC.…”