A New Human Uveal Melanoma Cell Line: Melanin Production and Molecular Markers for Targeted Therapy

A new human uveal melanoma (UM) cell line uMel1 was established by mechanical disintegration of a tumor fragment. uMel1 cells had a stellate dendrite-like shape, contained a lot of brown melanin pigment, and had a low mitotic index. Optimization of cultivation conditions led to an increase in the rate of cell proliferation and was accompanied by the loss of brown pigment. Since the melanin precursor is L-dihydroxyphenylalanine (L-DOPA), the authors analyzed the cultivation of uMel1 cells in the presence of L-DOPA. When L-DOPA was used at a concentration of 20 μg/mL, causing a decrease in cell viability by no more than 10%, melanocytes uMel1 synthesized melanin. It can be concluded that cultivation in the presence of L-DOPA provides the phenotype of melanin-containing melanocytes of uMel1 personal culture under conditions of long-term cultivation. Analysis of cell adhesion molecules N-cadherin (N-cad), E-cadherin (E-cad), and Mel-CAM, as well as receptors of the epidermal growth factor (ErbB) family by flow cytometry, showed that uMel1 cells have a phenotype of N-cad^–/E-cad^–/Mel-CAM⁺/HER2^low/HER3^low, and can be used for the study of targeted drugs to Mel-CAM, HER2 and HER3.