D2.433 - AllergoOncology: Immunocompetent 3D and Skin Organoid Models of Melanoma to Investigate Tumour-Immune Interactions and Immunotherapies

Melanoma accounts for 20% of skin cancer cases and has seen rising incidence rates over the past decades. Traditional monolayer cultures often fail to replicate the complexity of tumour biology, while animal models have limitations in translating results to human biology, underscoring the need for physiologically relevant human models. Recently, various three-dimensional (3D) cell culture approaches have been developed to mimic melanoma, offering more realistic tumour microenvironments that better recapitulate tumour progression for therapeutic studies. However, most existing 3D models lack immune components, limiting their ability to evaluate immunotherapies. 

To address this gap, we are developing immunocompetent 3D melanoma models to better understand melanoma-immune interactions and to evaluate antibody therapy. First, we generated multicellular spheroids by incorporating fibroblasts, melanoma cells, and co-cultured with immune cells. To further mimic the skin architecture and microenvironment, we are developing skin reconstruction organoid models by integrating melanoma spheroids with keratinocytes, fibroblasts, and immune cells layered within a collagen matrix. 

Confocal microscopy revealed that the spheroid model recapitulated several aspects of human melanoma, including a hypoxic core, necrotic areas, proliferating edges, and immune cell infiltration. Preliminary findings showed that the presence of fibroblasts enhances immune cell infiltration and alters the infiltration pattern within the tumour organoid. Additionally, monocytes exposed to the tumour microenvironment differentiated into tumour-associated macrophages bearing immunosuppressive markers, reflecting the phenotype of macrophages in patient lesions. In parallel, immunofluorescence staining demonstrated that the skin organoids recapitulated aspects of the tumour microenvironment including tumour growth, invasion, and immune cells interactions within the cutaneous organoid environment, with features comparable to those observed in human melanomas.

These immunocompetent human melanoma models providing conditions more congruent to human melanoma, offer a promising platform for the study of melanoma biology, immune interactions and responses to therapeutic agents including IgE immunotherapies in the field of AllergoOncology.