Effect of Gambogic acid on the regulation of hERG channel in K562 cells in vitro / 华中科技大学学报（医学）（英德文版）

Overexpression of human ether-脿-go-go (eag) related gene (hERG) has been found in a broad range of human leukemia cell lines and primary human leukemia. The block of hERG protein might be a potential therapeutic strategy for leukemia. Gambogic acid (GA) has recently exhibited marked anti-tumor potency on solid tumors of various derivations. Here, we investigated the anti-leukemia effects of GA and its relation to the regulation of hERG in K562 leukemia cells in vitro. K562 cells were treated with various concentrations of GA (0.125-8.0 micromol/L) for 0-72 h. MTT assay was used to evaluate the inhibition effect of GA on the growth of K562 cells. Cell apoptosis was measured through both Annexin-V FITC/PI double-labeled cytometry and transmission electron microscopy. Cell cycle regulation was studied by a propidium iodide method. RT-PCR and Western blot were applied to detect the expression level of hERG in K562 cells. GA presented striking growth inhibition and apoptosis induction potency on K562 cells in vitro in a time- and dose-dependent manner. The IC(50) value of GA for 24 h was 2.637+/-0.208 micromol/L. Moreover, GA induced K562 cells arrested in G(0)/G(1) phase, accordingly, cells in S phase decreased gradually, and no obvious changes were found in G(2)/M phase cells. Under the transmission electron microscopy, apoptotic bodies containing nuclear fragments were found in GA-treated K562 cells. After treatment with GA of 2.0 micromol/L for 24 h, the percentage of apoptotic cells was increased from 4.09% to 18.47% (P<0.01). Overexpression of hERG channel was found in K562 cells, while GA could down-regulate it at both protein and mRNA levels (P<0.01). It was concluded that GA exhibited its anti-leukemia effects partially through down-regulating the expression level of hERG channel in K562 cells, suggesting that GA may be a potential agent against leukemia with a mechanism of blocking hERG channel.

Effects of Gambogic Acid on the Regulation of Nucleoporin Nup88 in U937 Cells / 华中科技大学学报（医学）（英德文版）

In order to investigate the anti-leukemia effects of gambogic acid (GA) and its relation to the regulation of nucleoporin Nup88 in U937 cells in vitro, the inhibitory effect of GA on the growth of U937 cells was examined by using MTT assay. Apoptosis was detected by Annexin-Ⅴ FITC/PI double-labeled cytometry. Cell cycle regulation was studied by propidium iodide method. Both flow cytometry (FCM) and RT-PCR were employed to assess the expression of Nup88, and the localization of Nup88 was determined by confocal microscopy. The results indicated that GA had strong inhibitory effect on cell proliferation and apoptosis induction activity in U937 cells in vitro in a timeand dose-dependent manner. The 24-h IC50 value was (1.019±0.134) mg/L. Moreover, GA induced arrest of U937 cells in G0/G1 phase. Over-expression of Nup88 was found in U937 cells, whereas GA could significantly down-regulate both the protein and mRNA levels of Nup88. Nup88 was diffusely distributed between nucleus and cytoplasm and was located at the cytoplasmic side of nuclear rim,and occasionally in cytoplasm. It is suggested that GA exerts its anti-leukemia effects by regulating the expression and distribution of nucleoporin Nup88. It promises to be new agent for the treatment of acute leukemia.

Effects of gambogic acid on the regulation of nucleoporin Nup88 in U937 cells / 华中科技大学学报（医学）（英德文版）

In order to investigate the anti-leukemia effects of gambogic acid (GA) and its relation to the regulation of nucleoporin Nup88 in U937 cells in vitro, the inhibitory effect of GA on the growth of U937 cells was examined by using MTT assay. Apoptosis was detected by Annexin-V FITC/PI double-labeled cytometry. Cell cycle regulation was studied by propidium iodide method. Both flow cytometry (FCM) and RT-PCR were employed to assess the expression of Nup88, and the localization of Nup88 was determined by confocal microscopy. The results indicated that GA had strong inhibitory effect on cell proliferation and apoptosis induction activity in U937 cells in vitro in a time-and dose-dependent manner. The 24-h IC(50) value was (1.019+/-0.134) mg/L. Moreover, GA induced arrest of U937 cells in G(0)/G(1) phase. Over-expression of Nup88 was found in U937 cells, whereas GA could significantly down-regulate both the protein and mRNA levels of Nup88. Nup88 was diffusely distributed between nucleus and cytoplasm and was located at the cytoplasmic side of nuclear rim, and occasionally in cytoplasm. It is suggested that GA exerts its anti-leukemia effects by regulating the expression and distribution of nucleoporin Nup88. It promises to be new agent for the treatment of acute leukemia.

Effect on proliferation and apoptosis in RPMI-8226 human myeloma cells and regulation on steroid receptor coactivator-3 by deguelin / 中草药

Objective To investigate the effects of deguelin on the proliferation inhibition and apoptosis induction in RPMI-8226 cells in vitro,as well as the regulation of steroid receptor coactivator-3(SRC-3)to explore the relationship between them.Methods The effect of deguelin on the growth of RPMI-8226 cells was studied by MTT assay.Apoptosis was detected through Hoechst 33258 staining and Annexin-V FITC/PI double-labeled cytometry.RT-PCR Technology was applied to assessment of the mRNA expression of SRC-3,whereas,SRC-3 protein expression and localization were determined by using immunohistochemistry method.Results Deguelin presented striking proliferation inhibition potency on RPMI-8226 cells in vitro and apoptosis induction activity in a time-and dose-dependent manner.The IC50 value for 24 h was(54.55?0.40)nmol/L,(17.04?0.73)% RPMI-8226 cells went apoptotic when treated with 25 nmol/L deguelin for 24 h,with the dose of deguelin increasing to 100 nmol/L,(63.57?1.36)% cells were apoptotic.Over-expression of SRC-3 was found in RPMI-8226 cells,whereas the mRNA and protein expression levels of SRC-3 were significantly downregulated in RPMI-8226 cells induced by deguelin in a dose-dependent manner.The disposition of SRC-3 was situated mainly at the nuclear,occasionally in the cytoplasm.Conclusion Deguelin exhibited potent proliferation inhibition to the human myeloma cell line RPMI-8226 cells,furthermore,deguelin might induce RPMI-8226 cells apoptosis in a dose-dependent manner,which might correspond to the regulation of the expression of SRC-3.