Background: Melanoma is known to have high propensity to metastasize to the brain. This however, requires disruption of the blood-brain barrier (BBB) following interactions of adhesion molecules expressed on the brain endothelium and the melanoma. An increasing number of mechanisms have been implicated in melanoma mediated disruption of the BBB and their importance varies considerably in literature. In this study, we show another example of disparity between migration capabilities of adherent melanoma cells in comparison to a suspension sub-population, derived from the same adhesive counterpart.
Methods: Melanoma mediated barrier disruption of human cerebral microvascular endothelial cells (hCMVEC) was assessed using electrical cell-substrate impedance sensing (ECIS). Melanoma cell invasion was also imaged live using the Nikon BioStation. New Zealand melanoma (NZM) cells were also characterised for cell surface expression of adhesion molecules using flow cytometry.
Results: ECIS results revealed that suspension melanoma disrupt the human brain endothelium, primarily involving the transcellular route unlike what is observed by their adherent-cell counterpart, which take a paracellular route. The sensitivity of ECIS also revealed that this occurs within 20 min of the melanoma cells being added apically to the endothelium. Time-lapse imaging revealed opening within the endothelial cell-body (potentially disruption) by the invasive melanoma all within the first hour of addition.
Discussion: We suggest that the ability of melanoma to produce subtypes that are more invasive may play a big a role in aiding their capability to migrate through the brain endothelium. We aim to investigate what these melanoma subtypes are and explore the roles of large exosomes and macrovesicles in melanoma migration.