Cell Adhesion Experiments With Cell Lines Derived From Uveal Melanomas With Monosomy 3

Abstract

Abstract: : Purpose: The avidity of tumor cells to matrix compounds is very important for cell migration, cell invasion and the resulting establishment of metastases. Interactions between tumor cells and the extracellular matrix (ECM) are mainly mediated by integrins. The identification of integrins on the cell surface of UPMM–1 and UPMM–2 cells (cell lines derived from tumors with monosomy 3) and cell adhesion experiments on collagen type I, collagen type VI and matrigel may, therefore, characterize important cell matrix interactions. Methods: The cell lines UPMM–1 and UPMM–2 were examined for the expression of the integrins α1, α2, α3, α6, ß1 and ß4 on their cell surface by FACS analysis. Cell adhesion experiments were performed in multiwell plates using following matrix compounds: collagen type I, collagen type VI and matrigel. Cell adhesion in serum–free medium was measured after 90 minutes in a humidified incubator (5% CO₂–atmosphere, 37°C) with or without presence of rhodocetin (a potent inhibitor of α2ß1 integrin) by staining adherent cells with coomassie brilliant blue. Results: Though all examined integrins were found by FACS analysis on the cell surfaces of UPMM–1 and –2, the quantity of each integrin differs in dependence of the cell line. Both cell lines interacted avidly with collagen typeVI. On UPMM–1 this attachment can be negatively influenced by rhodocetin. The binding affinity to collagen type I was completely inhibited by rhodocetin for both cell lines. In contrast, rhodocetin did not affect the adhesion of melanoma cells to matrigel. Conclusions: Collagen type VI has previously been described by Folberg et al. to be involved in tumor progression in uveal melanoma. The high binding avidity of the cell lines UPMM–1 and UPMM–2, both derived from tumors with monosomy 3, indirectly confirmed a direct interaction of collagen type VI with uveal melanoma. Interestingly only UPMM–1 can be inhibited by rhodocetin. These results show that the different uveal melanoma cells differ in there integrin expression and their capability to interact with collagen VI. In addition, the tumoristatic potential of rhodocetin, which is known in other malignancies, requires further studies on these tumor cells.

Keywords: oncology • melanoma • extracellular matrix