COMPARATIVE-ANALYSIS OF INTEGRINS IN-VITRO AND IN-VIVO IN UVEAL AND CUTANEOUS MELANOMAS

Changes in integrin expression have been shown to be important for the growth and metastatic capacity of melanoma cells. in this study, we h ave examined the expression of uv integrins by three uveal and four cu taneous malanoma lines. No lines expressed alpha v beta 6 and only TXM 13, a cutaneous line, expressed alpha v beta 8. All lines expressed al pha v beta 5 and alpha v beta 3 (four out of four cutaneous, two out o f three uveal) or alpha v beta 1 (OM431, an uveal line), Thus, OM431 i s the second uveal melanoma we have described that expresses alpha v b eta 1 and this, we report again, functions as an alternative vitronect in/fibronectin receptor. Subcutaneous growth of cell lines in athymic mice correlated with an alpha v beta 3-positive, alpha v beta 1-negati ve phonotype. Analysis of clinical material from cutaneous melanoma sh owed that although alpha v expression was increased in 88% of metastas es, this could not all be explained by up-regulation of alpha v beta 3 , with only 2 out of eight skin metastases expressing this heterodimer . Using antibody SZ.21, which as we report here works in archival mate rial, only 1 out of 15 uveal metastases expressed detectable beta 3. T hus, acquisition of alpha v beta 3 expression, which has been implicat ed in cutaneous melanoma progression, may not be required for developm ent of metastases from uveal melanoma or indeed for skin, as distinct from lymph node, metastases of cutaneous melanoma.