Standard melanoma-associated markers do not identify the MM127 metastatic melanoma cell line

Abstract

Reliable identification of different melanoma cell lines is important for many aspects of melanoma research. Common markers used to identify melanoma cell lines include: S100; HMB-45; and Melan-A. We explore the expression of these three markers in four different melanoma cell lines: WM35; WM793; SK-MEL-28; and MM127. The expression of these markers is examined at both the mRNA and protein level. Our results show that the metastatic cell line, MM127, cannot be detected using any of the commonly used melanoma-associated markers. This implies that it would be very difficult to identify this particular cell line in a heterogeneous sample, and as a result this cell line should be used with care.Melanoma is an aggressive form of skin cancer that has the highest incidence rate in Australia 1 . Since many aspects of melanoma research rely on the use of various types of melanoma cell lines 2,3 , the reliable identification of different melanoma cell lines is very important.A range of melanoma-associated markers are used to identify different types of melanoma cell lines 4 . The three most frequently used markers are: S100; HMB-45 and Melan-A 5,6 . A common feature of many experimental investigations is that some melanoma cell lines are unable to be detected using certain markers 7 . To address this limitation, many studies use two different markers to ensure reliable identification 8 . MM127 is a metastatic melanoma cell line of human origin, isolated in 1970 9 . Since then, MM127 melanoma cells have been used in many published investigations. For example, MM127 cells have been used in ultraviolet radiation studies 10 , gene-based studies 11 , drug-response studies 12 and in other melanoma-associated research. Some of our previous work involves investigating how the balance of the rate of cell migration and the rate of cell proliferation affects the collective spreading of a population of MM127 melanoma cells 13 . In this previous study we describe results from an in vitro monoculture circular barrier assay 14,15 , and we use a discrete random walk mathematical model to quantify the rates of cell migration and cell proliferation in the experiment. Because this previous study involves a monoculture assay with just one cell type present, we did not attempt to identify the MM127 cells using any melanoma-associated markers. One way to extend this previous work would be to perform more complicated co-culture experiments. Such an extension would require the identification of the MM127 melanoma cells amongst the total population of cells in the assay. To meet this aim we first need to establish whether we can reliably identify MM127 melanoma cells using standard melanoma-associated markers. The focus of the present study is to explore whether MM127 cells can be reliably identified using standard approaches.This work is organised in the following way. In the Results section we describe the outcomes of three different experimental techniques for identifying different melanoma cell lines using S100, HMB-45, and Melan-A. These tec...

Investigating the Reproducibility of In Vitro Cell Biology Assays Using Mathematical Models

“…There are many ways in which passaging can affect cells. For example, primary cells, which are directly isolated from living tissues [41], undergo morphological changes and cumulative damage as the passage number increases [21,31,45,62,68,88,95,99]. As a result, the cell morphology, migration rate and proliferation rate can become increasingly varied, which is thought to increase the heterogeneity in cell lines [31,45,68,95,99].…”