| Objective To investigate the inhibitory effect of docetaxel on breast cancer cell line Bcap37 in vitro and elucidate the possible mechanisms. Methodes Bcap37 cells were treated with docetaxel at different concertrations and inhibition rate was tested by MTT method. The morphologic characteristics of the apoptosis induceded by docetaxel was assessed by the converting microscopy. DNA agrose gel electrophoresis and terminal deoxynucleotide transferase mediate dUTP nick-end-labeling method was applied to detecte the degradation of DNA. The rate of cell apoptosis was tested by using the Annexin-Fitic/PI fluorescence flow cytometry.Cell cycle was examined by PI fluorescence flow cytometry (FCM). Results The treatment of docetaxel remarkably inhibited the growth of Bcap37 cells, and inhibitory rate showed a dose-and-time-dependent effect (P < 0.001). Docetaxel could directly kill the tumour cells with high concentration (≥50 μ mol/L). With treatment of low concentration of docetaxel (≤ 10 μ mol/L) ,the changes in morphologic characteristics of apoptosis was observed. The cell apoptotic rates showed a dose-and-time-dependent effect (P < 0.001). DNA ladder was obtained with the agrose gel electrophoresis. Yellow and brown particles was observed in dUTP nick-end-labeling method. The rate of cell apoptosis showed a dose-and-time-dependent effect (P < 0.001).The proportionsof G2 phases cell increased with treatment of docetaxel at 24 ^ 48 ^ 72hour, but G2 phases cell at 72 hour was smaller than those at 24 > 48. The cell proportions in Gj phases increased at 72hour. Conclusion High concentration of docetaxel (^50umol/L) could kill breast cancer cell. Low concentration of docetaxel (^10umol/L) might induce the apoptosis in breast cancer cell line Bcap37. The mechanism probably is due to the blockade of the cycle in G2 phases. The blocking action of G2 phases by docetaxel has the time limitation, it was greatest at 48 hour. The most cells entranced G] phases at 72 hour. |
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