A Comparison of Differences in the Gene Expression Profiles of Phorbol 12-myristate 13-acetate Differentiated THP-1 Cells and Human Monocyte-derived Macrophage

In order to characterize the monocytic cell line THP-1 and its mature, macrophage-like form treated with phorbol 12-myristate 13-acetate (PMA), we have conducted an oligonucleotide microarray assay and compared the results with those from an assay of human monocytes and macrophages. We found that early THP-1 cells have a pattern of gene expression distinct from monocytes, and when treated with PMA, certain genes which are induced in macrophages, such as apolipoprotein-E, matrix metalloproteinase 9 and alpha2 macroglobulin are also induced in the PMA-treated THP-1 cells (THP1PMA cells). However, these were some genes which are conversely regulated among macrophages and THP1PMA cells such as interleukin-1-beta and the overall correlation coefficient was not very high. It is shown that, although certain morphological and other characteristics of PMA-differentiated THP-1 cells are similar to macrophages, from a transcriptomic view, the two are different. This suggests a need for careful recognition of and allowance for this difference when interpreting the results of experiments done with THP-1 cells in which it is otherwise assumed they are representative of the macrophage.