Article date: December 2000
By: Ming‐Jen Hsu, Jur‐Shan Cheng, Huei‐Chen Huang in Volume 131, Issue 7, pages 1285-1293
The mechanisms involved in the apoptotic effect of saikosaponin‐d, a triterpene saponin from Bupleurum falcatum L., were studied in human CEM lymphocytes and compared with those of dexamethasone (3×10−7 M).
Saikosaponin‐d (10−8 to 10−5 M) inhibited the serum‐stimulated [3H]‐thymidine incorporation in a concentration‐dependent manner. Dexamethasone also inhibited serum‐stimulated [3H]‐thymidine incorporation.
Cell viability was unaffected by saikosaponin‐d until 10−5–10−4 M. Dexamethasone significantly reduced the number of viable cells.
Following saikosaponin‐d (10−5–10−4 M) treatment, flow cytometry analysis of propidium iodide‐stained cells showed a significant increase in the percentage of cells in the apoptotic region. Dexamethasone also significantly increased the percentage of apoptotic cells. The supravital exposure to propidium iodide and annexin V labelling demonstrated that saikosaponin‐d (10−5–10−4 M) induced apoptosis as well as necrosis.
The apoptotic effect of saikosaponin‐d (3×10−6–10−4 M) was also demonstrated by TUNEL analysis and DNA laddering. The percentage of apoptotic cells induced by saikosaponin‐d (3×10−6–10−5 M) was unaffected by the presence of Z‐VAD‐FMK, indicating that saikosaponin‐d‐induced apoptosis may not be mediated by caspase activity. However, the percentage of apoptotic cells induced by dexamethasone was significantly reduced by the presence of Z‐VAD‐FMK.
Levels of c‐myc, p53, and bcl‐2 mRNA were analysed by the reverse transcription‐polymerase chain reaction. Levels of c‐myc and p53 mRNA were significantly increased, while the level of bcl‐2 mRNA was decreased, by saikosaponin‐d (10−5 M) treatment. Dexamethasone did not significantly change the expression of these genes.
It is suggested that the apoptotic effect of saikosaponin‐d may be partly mediated by increases in c‐myc and p53 mRNA levels accompanied by a decrease in bcl‐2 mRNA level.
The mechanisms involved in the apoptotic effect of saikosaponin‐d, a triterpene saponin from Bupleurum falcatum L., were studied in human CEM lymphocytes and compared with those of dexamethasone (3×10−7 M).
Saikosaponin‐d (10−8 to 10−5 M) inhibited the serum‐stimulated [3H]‐thymidine incorporation in a concentration‐dependent manner. Dexamethasone also inhibited serum‐stimulated [3H]‐thymidine incorporation.
Cell viability was unaffected by saikosaponin‐d until 10−5–10−4 M. Dexamethasone significantly reduced the number of viable cells.
Following saikosaponin‐d (10−5–10−4 M) treatment, flow cytometry analysis of propidium iodide‐stained cells showed a significant increase in the percentage of cells in the apoptotic region. Dexamethasone also significantly increased the percentage of apoptotic cells. The supravital exposure to propidium iodide and annexin V labelling demonstrated that saikosaponin‐d (10−5–10−4 M) induced apoptosis as well as necrosis.
The apoptotic effect of saikosaponin‐d (3×10−6–10−4 M) was also demonstrated by TUNEL analysis and DNA laddering. The percentage of apoptotic cells induced by saikosaponin‐d (3×10−6–10−5 M) was unaffected by the presence of Z‐VAD‐FMK, indicating that saikosaponin‐d‐induced apoptosis may not be mediated by caspase activity. However, the percentage of apoptotic cells induced by dexamethasone was significantly reduced by the presence of Z‐VAD‐FMK.
Levels of c‐myc, p53, and bcl‐2 mRNA were analysed by the reverse transcription‐polymerase chain reaction. Levels of c‐myc and p53 mRNA were significantly increased, while the level of bcl‐2 mRNA was decreased, by saikosaponin‐d (10−5 M) treatment. Dexamethasone did not significantly change the expression of these genes.
It is suggested that the apoptotic effect of saikosaponin‐d may be partly mediated by increases in c‐myc and p53 mRNA levels accompanied by a decrease in bcl‐2 mRNA level.
British Journal of Pharmacology (2000) 131, 1285–1293; doi:10.1038/sj.bjp.0703559
DOI: 10.1038/sj.bjp.0703559
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