Effect of extracellular S100A4 on melanoma cells of different phenotypes

S100A4 is a known metastasis-promoting factor, rich in the tumor microenvironment. To clarify how extracellular S100A4 execute its pro-metastatic function, we analyzed gene expression in melanoma cells stimulated with recombinant protein rS100A4 and compared it to the expression in control non-stimulated cells. Two melanoma cell lines representing two distinct phenotypes – invasive (Melmet 1) and non-invasive/proliferative (Melmet 5) – were included in the study. The response at the gene expression level was much stronger in Melmet 5 than in Melmet 1. Melmet 5 down-regulated genes associated with melanocytic differentiation, indicating that Melmet 5 cells gained dedifferentiated, more invasive phenotype after stimulation with rS100A4. The observed changes in the expression of metabolism associated genes suggested the occurrence of metabolic reprogramming. We conclude that extracellular S100A4 stimulate the transition to the invasive phenotype in poorly-invasive melanoma cells, and that this transition is associated with metabolic reprogrammingve Total RNA was isolated from Melmet 1 and Melmet 5 cells stimulated with rS100A4 protein for 48hrs compared to non-stimulated cells.

S100A4是一类已知的促转移因子，在肿瘤微环境中富集。为阐明细胞外S100A4如何发挥其促转移功能，本研究对经重组蛋白rS100A4刺激的黑色素瘤细胞进行基因表达分析，并与未受刺激的对照组细胞的基因表达水平进行对比。本研究纳入了两种代表不同表型的黑色素瘤细胞系——侵袭性表型的Melmet 1，以及非侵袭性/增殖性表型的Melmet 5。结果显示，Melmet 5的基因表达响应强度远高于Melmet 1。在Melmet 5中，与黑素细胞分化相关的基因表达下调，表明经rS100A4刺激后，Melmet 5细胞获得了去分化且侵袭性更强的表型。观察到的代谢相关基因表达变化提示细胞发生了代谢重编程。我们得出结论：细胞外S100A4可诱导低侵袭性黑色素瘤细胞向侵袭性表型转化，且该转化与代谢重编程密切相关。本研究从经rS100A4蛋白刺激48小时的Melmet 1和Melmet 5细胞中分离总RNA，并以未刺激细胞作为对照。