Micropillar Topography Regulates Morphology and Melanogenesis in Melanoma Cells

Microscale physical cues at the cell–extracellular matrix adhesion interface are increasingly being recognized as important regulators of cellular behavior. B16-F10 melanoma-derived cells retain melanogenic activity, including microphthalmia-associated transcription factor (MITF) expression and inducible melanin production, and are widely used for studies of melanogenesis and pigmentation-associated cellular responses. Melanocytic cells are sensitive to the physical characteristics of the surrounding microenvironment, including adhesion-dependent mechanical cues. However, the mechanism by which physical cues derived from the adhesion interface regulate melanoma cell function remains incompletely understood. In this study, we investigated the mechanism by which defined micropatterned substrates modulate melanoma cell morphology, migration, nuclear architecture, and melanogenic activity. Polydimethylsiloxane substrates with pillar- and hole-shaped microstructures (5, 10, and 50 µm diameters and spacings; 10 µm height or depth) were fabricated and coated with fibronectin. B16-F10 melanoma cells cultured on narrow pillar patterns (5 and 10 µm) exhibited restricted cell spreading, shortened protrusions, suppressed migration, and pronounced nuclear deformation compared with flat substrates. These mechanical constraints were accompanied by significant reductions in melanin production and downregulation of melanogenesis-related genes (Mitf, Tyr, and Tyrp1). Comparable trends were observed for Matrigel-coated substrates, indicating that microscale topography exerted consistent effects on B16-F10 melanoma cell responses across the tested extracellular matrix conditions. Collectively, our results demonstrate that surface topography with narrow pillar microstructures is associated with topography-dependent changes in cell behavior and melanogenic activity, providing insights into how microscale topographic confinement influences melanoma cell morphology and melanogenic activity.