MODULATION OF ALPHA-4-BETA-1 AND ALPHA-5-BETA-1 INTEGRIN EXPRESSION -HETEROGENEOUS EFFECTS OF Q-SWITCHED RUBY, ND-YAG, AND ALEXANDRITE LASERS ON MELANOMA-CELLS IN-VITRO

Background and Objective: Integrins of the beta 1 family are cellular adhesion molecules that play an important role in cell attachment and migration by interacting with extracellular matrix molecules. Agents s uch as hormones, cytokines, and ultraviolet radiation have all been sh own to have an integrin modulating potential. The present study indica tes that radiation of Q-switched lasers is also able to induce transie nt changes in integrin expression levels on human melanoma cells in vi tro. Study Design/Materials and Methods: Radiation from Q-switched Rub y (694 nm), Alexandrite (755 nm), and Nd:YAG laser (1,064 nm) with flu ences comparable to those that are generally used in treating dermatol ogic lesions were used to irradiate a subconfluent layer of human mela noma cells. After fixed time intervals, the cells were harvested eithe r to analyse the integrin expression by flow cytometry or to investiga te changes in cell attachment, spreading, and migration. Results: It w as established that all three types of laser were able to cause a sign ificant downregulation of both the alpha 4 and the common beta 1 integ rin subunit. The Alexandrite and Ruby lasers also induced a decrease i n alpha 5 expression; however, the cells treated with the Nd:YAG laser showed a marked upregulation of the alpha 5 subunit. The expression o f the other beta 1 integrin subunits was shown to be unaltered after l aser treatment. Downregulation of the alpha 4 upregulation of the alph a 5 integrin subunit expression resulted in, respectively, decreased a nd increased attachment and spreading on fibronectin, the extracellula r matrix ligand for both the alpha 4 beta 1 and alpha 5 beta 1 integri ns. Marked upregulation of the alpha 5 subunit also resulted in a high er migration rate. Conclusion: Taken together, these results show that nonlethal doses of Q-switched laser radiation are able to induce chan ges in cellular behavior in vitro by modulating the integrin expressio n pattern. (C) 1996 Wiley-Liss, Inc.