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DOI: 10.1055/s-2002-20255
© Georg Thieme Verlag Stuttgart · New York
In Vitro Modulation of Telomerase Activity, Telomere Length and Cell Cycle in MKN45 Cells by Verbascoside
Publication History
February 2, 2001
June 17, 2001
Publication Date:
22 February 2002 (online)
Abstract
Screening of natural products with anti-tumor activity as telomerase inhibitor is a new subject in the field of tumor therapy. Using telomerase PCR ELISA, telomere DNA hybridization and flow cytometry analysis, the effects of verbascoside, a phenylpropanoid glucoside extracted from Pedicularis striata Pall, on telomerase activity, telomere length and cell cycle of human gastric carcinoma cells MKN45 was examined in vitro. After being treated with a 50 % inhibition concentration of verbascoside (17.8 μg/ml), telomerase activity in the cells was significantly inhibited but not in the cellular supernatant, the average telomere length became remarkably short, and the sub-G0 /G1 peak and G2/M arrest were also displayed when compared to the control cells. These results suggest that verbascoside mediated-cell differentiation and apoptosis may be affected by telomere-telomerase-cell cycle dependent modulation. Thus, the antitumor mechanism of verbascoside is demonstrated once more by its inhibiting effect on telomerase activity in tumor cells, and the telomerase assay may provide a valuable screening method for antitumor activity of natural products.
Abbreviations
PCR:polymerase chain reaction
ELISA:enzyme-linked immunosorbent assay
DDW:disinfected distillation water
TRAP:telomere repeat amplification protocol
PPG:phenylpropanoid glycoside
RT:room temperature
OD:optical density
telIC50:50 % inhibition of the telomerase activity
TRF:telomeric restriction fragments
FCM:flow cytometry
NC:nitrocellulose
Abstract
Screening of natural products with anti-tumor activity as telomerase inhibitor is a new subject in the field of tumor therapy. Using telomerase PCR ELISA, telomere DNA hybridization and flow cytometry analysis, the effects of verbascoside, a phenylpropanoid glucoside extracted from Pedicularis striata Pall, on telomerase activity, telomere length and cell cycle of human gastric carcinoma cells MKN45 was examined in vitro. After being treated with a 50 % inhibition concentration of verbascoside (17.8 μg/ml), telomerase activity in the cells was significantly inhibited but not in the cellular supernatant, the average telomere length became remarkably short, and the sub-G0 /G1 peak and G2/M arrest were also displayed when compared to the control cells. These results suggest that verbascoside mediated-cell differentiation and apoptosis may be affected by telomere-telomerase-cell cycle dependent modulation. Thus, the antitumor mechanism of verbascoside is demonstrated once more by its inhibiting effect on telomerase activity in tumor cells, and the telomerase assay may provide a valuable screening method for antitumor activity of natural products.
Abbreviations
PCR:polymerase chain reaction
ELISA:enzyme-linked immunosorbent assay
DDW:disinfected distillation water
TRAP:telomere repeat amplification protocol
PPG:phenylpropanoid glycoside
RT:room temperature
OD:optical density
telIC50:50 % inhibition of the telomerase activity
TRF:telomeric restriction fragments
FCM:flow cytometry
NC:nitrocellulose
Key words
Verbascoside - Pedicularis striata - Scrophulariaceae - telomere - telomerase - cell cycle - human gastric carcinoma cell MKN45
Key words
Verbascoside - Pedicularis striata - Scrophulariaceae - telomere - telomerase - cell cycle - human gastric carcinoma cell MKN45