Résumé
The aim of this study was to explore the effect of gambogic acid (GA) on MDS SKM-1 cell proliferation, apoptosis and their possible mechanism. Cell proliferation was determined by MTT method. The apoptosis percentage and cell cycle regulation of SKM-1 cells were analyzed by flow cytometry. Morphological features were observed by light microscopy. The mRNA expression of bcl-2 and bax were detected by RT-PCR. The results showed that GA could inhibit the proliferation of SKM-1 cells in a dose- and time-dependent manner (IC50 was 0.37 µg/ml at 48 h), increase the apoptotic percentage of SKM-1 cells, and arrest cell cycle at the G0/G1. The expression of bax mRNA was up-regulated while that of bcl-2 mRNA was down-regulated in SKM-1 cells treated with GA for 48 h. It is concluded that GA can induce apoptosis, which may be related to its effect of arresting cells at phase of G0/G1 and down-regulating bcl-2/bax ratio.
Sujets)
Humains , Apoptose , Points de contrôle du cycle cellulaire , Lignée cellulaire tumorale , Prolifération cellulaire , Syndromes myélodysplasiques , Métabolisme , Anatomopathologie , Protéines proto-oncogènes c-bcl-2 , Métabolisme , Xanthones , Pharmacologie , Protéine Bax , MétabolismeRésumé
This study was purposed to investigate the reversal effect of gambogic acid (GA) on multidrug resistance of K562/A02 cells and its mechanism. The IC(50) (half maximal inhibitory concentration) of adriamycin (ADM) was evaluated by MTT. Cell apoptosis was detected by flow cytometry. Morphological changes of K562/A02 cells were observed by fluorescent microscopy with DAPI staining. The expressions of Survivin and P-gp were determined by Western blot. The results showed that the IC(50) of ADM on K562 and K562/A02 cell proliferation were (1.42 ± 0.07) µg/ml and (28.42 ± 1.40) µg/ml respectively. GA ≤ 0.0625 µmol/L had no inhibitory effect on proliferation of K562 and K562/A02. 0.0625 µmol/L GA could enhance the sensitivity of K562/A02 cells to ADM (P < 0.05) and the reversal multiples was 1.53. The apoptotic rate was raised after treating with ADM combined with 0.0625 µmol/L GA for 48 h (P < 0.05). Morphological differences were typical and obvious between cells of control and treated groups under fluorescence microscopy using DAPI staining. After treating K562/A02 cells with ADM combined with 0.0625 µmol/L GA for 48 h, the expressions of Survivin and P-gp were down-regulated at protein levels. It is concluded that GA can enhance the sensitivity of K562/A02 cells to ADM, which may be related to increasing cell apoptosis and down-regulating expressions of Survivin and P-gp.