Comparison of the gene expression profiles of monocytic versus granulocytic lineages of HL-60 leukemia cell differentiation by DNA microarray analysis

It is now recognized that precise patterns of differentially expressed genes ultimately direct a particular cell toward a given lineage. In this study, we compared the expression profiles of cancer-related genes by cDNA microarray analysis during the differentiation of human promyelocytic leukemia HL-60 cells into either monocytes or granulocytes. RNA was isolated at times 0, 6, 12, 24, 36, 48, and 72 h following stimulation of differentiation with all-trans retinoic acid (all-trans RA) or 1,25-dihydroxyvitamin D₃ [1,25-(OH)₂D₃], and hybridized to the microarray gene chips containing 872 genes related to cell-cycles, oncogenes and leukemias. Several genes were commonly or differentially regulated during cell differentiation into either lineage, as demonstrated by both hierarchical and self-organizing map clustering analysis. At 72 h the expression levels of 45 genes were commonly up- or down-regulated at least a twofold in both lineages. Most importantly, 32 genes including α-L-fucosidase gene and adducin γ subunit gene were up- or down-regulated only in all-trans RA-treated HL-60 cells, while 12 genes including interleukin 1β and hypoxia-inducible factor 1α were up- or down-regulated only in 1,25-(OH)₂D₃-treated HL-60 cells. The expression of selected genes was confirmed by Northern blot analysis. As expected, some genes identified have not been examined during HL-60 cell differentiation into either lineage. The identification of genes associated with a specific differentiation lineage may give important insights into functional and phenotypic differences between two lineages of HL-60 cell differentiation.