In-vitro melanoma models

Abstract

A critical first step in the metastatic progression of cutaneous melanoma, invasive growth into the dermal compartment, would ideally be studied in the proper three-dimensional tissue microenvironment. In this study, we compared the growth and behavior of four melanoma cell lines originating from primary and metastatic human cutaneous melanomas (AN, RU, M14, and WK) in in-vitro human skin equivalents (HSEs) generated with four different dermal matrices: human fibroblast-seeded rat tail collagen, human fibroblast-derived matrix (FDM), noncellular human de-epidermized dermis (DED), and a novel fully cellular human DED with an intact pre-existent basement membrane. Melanoma cells showed proliferation in all HSEs, indicating that the microenvironment formed in all HSEs studied here allows the growth of melanoma cells in concert with epidermal keratinocytes for multiple weeks in vitro. Melanoma cells did not affect epidermal proliferation and terminal differentiation. Growth of melanoma cells in the dermal compartment, as a measure of invasive potential, differs markedly between the four types of in-vitro human melanoma models. Notably, the growth of melanoma cells in the dermal matrix was observed in all HSEs cultured with cell lines originating from metastatic melanoma, except for cDED-based HSEs, and the growth of melanoma cells of nonmetastatic origin was observed in the dermal compartment of FDM-based HSEs. Our results show that the type of dermal equivalent and the presence of an intact basement membrane should be taken into consideration when studying melanoma invasion using in-vitro HSEs.

A shift from papillary to reticular fibroblasts enables tumour–stroma interaction and invasion

“…However, when modelling invasion, the BM should be first fully formed and functional before any invasion in underlying connective tissue may proceed. 22…”

“…Rat-tail collagen dermal matrices were constructed as described earlier. 22 Subsequently, each of the constructs were seeded with 5 × 10 4 SCC cells (MET1, MET2, MET4 or SCC12b2). For the co-culture, these SCC cells were mixed with NHEKs (1:4) prior to seeding.…”

From simplicity to complexity in current melanoma models

“…Metastatic melanoma cell growth was observed in all Mel‐RhS, except for cDED‐based Mel‐RhS, and the growth of melanoma cells derived from a primary lesion was only observed in FDM‐based Mel‐RhS. 127 In addition to studies on melanoma progression and dermal invasion, 23 , 127 , 128 , 130 Mel‐RhS based on a human fibroblast‐populated rat‐tail collagen matrix has also been used to investigate the biological characteristics of patients‐isolated melanoma cells and further characterize melanoma subtypes in a 3D in vitro setting. 131 …”

“…Human fibroblast‐populated rat‐tail collagen, FDM, acellular DED, and cellular DED (cDED) were compared in the generation of Mel‐RhS models and were found to differentially influence growth and invasiveness of melanoma cells. 127 In particular, dermal spreading of melanoma cells, as a measure of invasive potential, differed between the four tested matrices. Metastatic melanoma cell growth was observed in all Mel‐RhS, except for cDED‐based Mel‐RhS, and the growth of melanoma cells derived from a primary lesion was only observed in FDM‐based Mel‐RhS.…”

“… 121 , 122 On the other hand, the use of pre‐assembled MCTSs does not mimic the sequential stages of melanomagenesis, which can be studied when melanoma cells are placed on top of the dermal matrix prior to or co‐seeded with keratinocytes. 117 , 123 , 124 , 125 , 126 , 127 , 128 In this latter case, Mel‐RhS can be used to spatiotemporally investigate melanoma progression and spread, providing a unique tool to help elucidate the molecular mechanisms underlying the switch from RGP to VGP to the metastatic cascade.…”