¹BioTechnological Center, University of Technology Dresden, Tatzberg 49, D-01307 Dresden, Germany

Correspondence: Dr K Poole, JPK Instruments, Bouchestrasse 12, 12435 Berlin, Germany. E-mail: poole@jpk.com

Received 16 August 2004; Revised 16 December 2004; Accepted 15 February 2005.

Abstract

Using a combination of laser-scanning confocal microscopy and atomic force microscopy, we have identified flexible, actin-based structures on the surface of cells derived from the vertical growth phase of melanoma progression. These flexible structures, lacking on the surface of mature melanocytes, were observed on the surface of all four melanoma cell lines tested. Further investigation revealed that the 1 integrin colocalises with these actin-based ridges on the cell surface, whereas 1 integrin distribution in melanocytes did not correlate with actin-based structures. Fibronectin staining on the surface of melanoma cells was partially codistributed with the ridges. The combination of structural information derived from atomic force microscopy images and fluorescent imaging of the distribution of labelled proteins involved in invasion and metastasis has allowed us to identify a common feature that may be involved in disease progression, at the surface of vertical growth phase melanoma cells, despite the known variation in genetic composition of melanoma.