kh-1060 and Leukemia--Myeloid--Acute

Treatment of human myeloblastic leukemia ML-1 cells with the phorbol ester TPA in combination with the vitamin D(3) analogue KH1060 will induce a synergistic differentiation to mature macrophage with multinuclei. To investigate the mechanism underlying this differentiation and the synergistic effect, a cDNA microarray and Northern blot analysis were used to examine gene expression profiles of ML-1 cells treated with TPA and/or KH1060. Results show that KH1060 enhanced several TPA-induced gene expressions and that TPA enhanced several KH1060-induced gene expressions. Studies with inhibitors of signaling molecules suggested that PKC and MAPK pathways play an important role in the differentiation induced by TPA and KH1060, and that they are associated with the synergistic induction of genes. The results of this study indicate the possibility that the expression of various genes are induced synergistically by cross-talk between TPA and KH1060 signals. It is likely that the synergistic effect on gene expression leads to the synergistic induction of differentiation by both reagents.

Topics: Base Sequence; Blotting, Northern; Calcitriol; Cell Differentiation; Cell Line, Tumor; DNA Primers; Gene Expression Regulation; Humans; Leukemia, Myeloid, Acute; Macrophages; Tetradecanoylphorbol Acetate

We reported previously that diverse combination of the vitamin D(3) analogue KH1060 together with 12-O-tetradecanoylphorbol-13-acetate (TPA) synergistically induces the differentiation of ML-1 cells into mature macrophages. To investigate the mechanism involved in their interaction, we examined the role of protein kinase C (PKC) in the differentiation of ML-1 cells to mature macrophages. We found that the specific PKC inhibitor GF109203 suppressed the morphological change and the alpha-naphthyl acetate esterase activity induced in ML-1 cells by treatment with KH1060 plus TPA. This treatment increased the translocation of PKC alpha, PKC epsilon, and PKC theta from cytosol to membranes. ML-1 cells treated with KH1060 alone increased translocation of PKC theta, whereas cells treated with TPA alone increased translocation of PKC alpha and PKC epsilon. These data showed that in human myeloblastic leukemia cells, diverse isoforms of PKC, including PKC alpha, epsilon, and theta, participate in the regulation of cell differentiation.

Topics: Calcitriol; Cell Differentiation; Humans; Isoenzymes; Leukemia, Myeloid, Acute; Mitogen-Activated Protein Kinases; Protein Kinase C; Protein Kinase C-alpha; Protein Kinase C-epsilon; Protein Kinase C-theta; Tetradecanoylphorbol Acetate; Tumor Cells, Cultured