Ginsenoside Rh2 and Rh3 induce differentiation of HL-60 cells into granulocytes: modulation of protein kinase C isoforms during differentiation by ginsenoside Rh2.
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 G1/S phase, consistent with the ability to induce differentiation in a decreasing order of retinoic acid > G-Rh2 > G-Rh3. During differentiation by G-Rh2, Ca2+/phospholipid-dependent PKC activity was increased in both the cytosol and total cell extract and Ca2+/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 alpha level, however, the immunoreactive 60 kDa band of a similar mass to the PKC catalytic fragment appeared following treatment with G-Rh2. The beta isoform was gradually increased with prolonged treatment. The gamma 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.
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Korea Ginseng and Tobacco Research Institute, Yousong-Gu, Taejon, South Korea.
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D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology; D002453:Cell Cycle / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects* / Q000502:physiology; D004365:Drugs, Chinese Herbal / Q000494:pharmacology; D036145:Ginsenosides; D006098:Granulocytes / Q000166:cytology / Q000187:drug effects / Q000201:enzymology; D018922:HL-60 Cells; D006801:Humans; D007527:Isoenzymes / Q000378:metabolism*; D005894:Panax; D010766:Phosphorylation; D010946:Plants, Medicinal; D011493:Protein Kinase C / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism; D012503:Saponins / Q000494:pharmacology*; D014212:Tretinoin / Q000494:pharmacology
D000972:Antineoplastic Agents, Phytogenic; D004365:Drugs, Chinese Herbal; D036145:Ginsenosides; D007527:Isoenzymes; D011506:Proteins; D012503:Saponins; C055306:ginsenoside Rh3; D014212:Tretinoin; C055305:ginsenoside Rh2; D011493:Protein Kinase C