Ginsenoside Rh1 or Rh2 differentiated B16 melanoma or F9 teratocarnoma to phenotypic normal melanocyte-like cells or parietal endoderm-like cells. Ginsenoside Rh3 and Rh4 were recently isolated from Panax ginseng, but their biochemical and pharmacological effects remain unidentified. The present study investigated whether the ginsenoside Rh group (G-Rh1, -Rh2, -Rh3 and -Rh4) having similar structures induce differentiation of HL-60 cells and whether protein kinase C (PKC) is involved in differentiation by ginsenoside. Differentiation was assessed by Wright-Giemsa stain and nitroblue tetrazolium reduction. G-Rh2 and G-Rh3 induced differentiation of HL-60 cells into morphologically and functionally granulocytes but G-Rh1 and G-Rh4 did not. G-Rh2 and G-Rh3 arrested the cell cycle at the GI/S phase, consistent with the ability to induce differentiation in a decreasing order of retinoic acid > GRh2>G-Rh3. During differentiation by G-Rh2, Ca2+/phospholipid-dependent PKC activity was increased in both the cytosol and total cell extract and 2+ Ca/phospholipid-dependent phosphorylation of 38 and 200 kDa endogenous proteins increased, while phosphorylation of 60, 64, 66 and 97 kDa proteins was Ca2+/phospholipid-independent. When cytosolic PKC isoforms were analyzed by immunoblotting, no significant change was observed in the α level, however, the immunoreactive 60 kDa band of a similar mass to the PKC catalytic fragment appeared following treatment with G-Rh2. The β isoform was gradually increased with prolonged treatment. The γ isoform was not detected in the cytosol of untreated cells, whereas a small amount was detected 5 days after treatment. It is concluded that G-Rh2 and G-Rh3 can induce differentiation of HL-60 cells into granulocytes and modulation of PKC isoform levels may contribute to differentiation of HL-60 cells by G-Rh2.
differentiation, protein kinase C, ginsenoside, HL-60 cells
NCBI PubMed ID: 9611775Publication DOI: 10.1016/S1357-2725(97)00141-6Journal NLM ID: 9508482Publisher: Amsterdam: Elsevier
Institutions: Korea Ginseng and Tobacco Research Institute, Taejeon, South Korea
Methods: 13C NMR, 1H NMR, FAB-MS, biological assays, immunoblotting, extraction
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