Skin Organ Constructs for In Vitro Modeling of Melanoma Invasion

Melanoma progression from an in situ lesion to an invasive dermal tumor is strongly associated with poor patient prognosis, with depth of invasion serving as a predictor of survival. Increasing evidence indicates that remodeling of the extracellular matrix (ECM) plays a central role in this transition by altering both mechanical and biochemical cues within the tumor microenvironment. To facilitate mechanistic studies of ECM-mediated melanoma invasion, we developed a reproducible in vitro skin organ construct (SOC) model that recapitulates key structural and cellular features of human skin. The SOC system is assembled using a two-layer collagen-based dermal equivalent containing primary human dermal fibroblasts, overlaid with normal human epidermal keratinocytes to generate a stratified epidermis. Melanoma cells are subsequently seeded onto the reconstructed epidermal surface and cultured under defined conditions, including staged modulation of epidermal growth factor and exposure to an air-liquid interface to promote keratinization. The model permits incorporation of defined ECM components or genetically modified melanoma cells to evaluate their impact on tumor invasion. Melanoma progression is assessed by measuring radial growth and quantifying invasion depth and patterns in paraffin-embedded sections using histological and immunohistochemical analyses. This SOC platform provides a physiologically relevant and customizable system to investigate ECM-driven mechanisms of melanoma invasion and to evaluate candidate therapeutic targets that modulate tumor-microenvironment interactions.