Abstract
Purpose::
Integrins are responsible for cell-matrix interactions. Aggressive uveal melanoma cell lines are able to form vasculogenic cords in vitro on thin matrigelTM layers. There is accumulating evidence that integrins may be involved in the formation of these patterns. The scope of the present study is to evaluate the impact of integrins upon the formation of vasculogenic cords by uveal melanoma cells on an artificial matrix.
Methods::
FACS-analysis for several integrins (alpha 1, -2, -3, -6 and beta 1, -4) was performed in order to detect the expression on the cell surface of the uveal melanoma cell lines UPMM-1, UPMM-2 (both derived from a tumor with monosomy of chromosome 3). Several aliquots of 40000 cells of each cell line were seeded on miniaturized collagen gels or on matrigelTM gels. The tendencies for vasculogenic cord formation of both cell lines were compared. Melanoma cell lines were treated with 2 µM antisense oligonucleotide for the integrins alpha 2, -3 and integrin beta 1 for three days under standard cell culture conditions. Treated and untreated cells were seeded on miniaturized matrigel gels and formation of network structures was observed and compared. Additionally cell migration tendencies were tested in a micro chemotaxis chamber for both examined cell lines.
Results::
After one day of cultivation on collagen and on matrigel UPMM-1 and UPMM-2 showed vasculogenic cord formation. The cords remained stable for the complete cultivation period of 25 days. The integrins alpha 2 and 3 and beta 1 were detected on both cell lines; above all integrin alpha 3 was highly expressed. Antisense oligonucleotide treatment of the cell lines had no avoiding effect for their vasculogenic cord formation, neither the application on one singled integrin nor the combined application on all integrins. But integrin beta 1 inhibition reduced melanoma cell migration significantly.
Conclusions::
The postulated involvement of integrins in vasculogenic cord formation could not be confirmed, but a beta 1 integrin dependence of cell migration was demonstrated. However, due to the limited number of examined integrins and cell lines the results should be considered preliminary.
Keywords: melanoma • uvea • cell adhesions/cell junctions