Objective： To investigate the inhibitory effect of interferon-α （IFN-α） and curcumin on proliferation of Raji cells （B-NHL） and its mechanism. Methods： The morphological, changes of Raji cells were observed in culture medium with IFN-α （500, 1000, 2000, 3000 U/L） and various concentrations of curcumin （6.25, 12.5, 25 μmol/L） for different time in vitro. The inhibitory ratio was measured by MTT assay. Apoptosis was detected by flow cytometry （FCM）. The expression of caspase 6, caspase 8 and caspase 9 in Raji cells treated with IC5025 μmol/L curcumin with IFN-α was examined using Western blot. Results： IFN-α and curcumin could significantly inhibit the growth and induce apoptosis of RAji cells with synergistic effects. They could increase the expression of caspase 6, caspase 8 and caspase 9 in Raji cells in a dose- and time-dependent manner. Conclusion： The combined use of IFN-α and curcumin can inhibit the proliferation of B-NHL Raji cells apparently in vitro. Promotion of the expression of caspase 6, caspase 8, caspase 9 and induction of apoptosis might be one of the important mechanisms.
OBJECTIVE Curcumin is the major component of the spice turmeric and the yellow pigment in curry powder. Many studies have shown that curcumin （diferuloylmethane） has significant antiproliferative and apoptotic effects in cancer cells by several mechanisms. Signal transducers and activators of transcription （STAT） proteins are critical in mediating a response in hematopoietic cells. This study was designed to investigate whether curcumin is associated with proteins involved in signal transduction and activation of transcription （STAT） and to investigate the expression of signal transducers and activators of transcription and the significance of the STAT5 signaling pathway of by treating k562 cells and cells from CML patients with curcumin. METHODS The study was divided into the following groups： normal control cells （human bone marrow cells）, untreated K562 cells, curcumin treated K562 cells, IFN-γ treated K562 cells, curcumin plus IFN-γ treated K562 cells, and CML patient cells with and without curcumin treatment. Cell proliferation was measured by the MTT assay. The expression of STAT5 mRNA was determined by RT-PCR. The expression of the STAT5 protein was assayed by Western-blotting and the expression of STAT5 in K562 cells was examined under confocal laser-scanning microscopy. The expression of STAT5 mRNA of K562 cells was determined with in situ hybridization. EMSA was used to assess the change in binding of STAT5 with DNA in CML patient cells. RESULTS The proliferation of the K562 cells and CML primary cells was decreased in the curcumin-treated group and/or IFN-γ group. The expression of STAT5 mRNA and protein were decreased the curcumin-treated group as compared with the K562 untreated group （P〈0.01）. STAT5 mRNA and protein expression was decreased in the IFN-γ group compared to the untreated K562 group （P〈0.01）. Combined use of curcumin with IFN-γ inhibited the proliferation of K562 cells and decreased the expression of STAT5 mRNA and protein of the K562 cells. For the CM
The effects of Trichostatin A （TSA） on histone deacetylase 8 （HDAC8） expression, proliferation and cell cycle arrest in T-lymphoblastic leukemia cell line Molt-4 cells in vitro were investigated. The effect of TSA on the growth of Molt-4 cells was studied by MTT assay. Flow cytometry was used to examine the cell cycle. The expression of HDAC8 was detected by using immunocytochemistry and Western blot. The results showed that proliferation of Molt-4 cells was inhibited in TSA-treated group in a time- and dose-dependent manner, The IC50 of TSA exposures for 24 h and 36 h were 254.3236 and 199.257 μg/L respectively. The cell cycle analysis revealed that Molt-4 was mostly in G0/G1 phase, and after treatment with TSA from 50 to 400 μg/L for 24 h, the percents of G0/G1 cells were decreased and cells were arrested in GJM phase. Treatment of TSA for 24 h could significantly inhibit the expression of HDAC8 protein in Molt-4 cells （P〈0.01）. It was concluded that TSA could decrease the expression of HDAC8 in Molt-4 cells, which contributed to the inhibition of proliferation and induction of cell cycle arrest in Molt-4 cells.
The expression of human general control of amino acid synthesis protein 5 （hGCN5） in human Burkitt＇s lymphoma Daudi cells in vitro, effects of Trichostatin A （TSA） on cell proliferation and apoptosis and the molecular mechanism of TSA inhibiting proliferation of Daudi cells were investigated. The effects of TSA on the growth of Daudi cells were studied by 3-（4, 5-dimethyl-2-thiazolyl）-2,5-diphenyl-2H-tetrazolium （MTT） assay. The effect of TSA on the cell cycle of Daudi cells was assayed by a propidium iodide method. Immunochemistry and Western blot were used to detect the expression of hGCN5. The proliferation of Daudi cells was decreased in TSA-treated group with a 24 h IC50 value of 415.3979 μg/L. TSA induced apoptosis of Daudi cells in a timeand dose-dependent manner. Treatment with TSA （200 and 400 μg/L） for 24 h, the apoptosis rates of Daudi cells were （14.74±2.04） % and （17.63±1.25） %, respectively. The cell cycle was arrested in G0/G1 phase （50, 100 μg/L） and in G2/M phase （200 μg/L） by treatment with TSA for 24 h. The expression of hGCN5 protein in Daudi cells was increased in 24 h TSA-treated group by immunochemistry and Western blot （P〈0.05）. It was suggested that TSA as HDACIs could increase the expression of hGCN5 in Daudi cells, and might play an important role in regulating the proliferation and apoptosis of B-NHL cell line Daudi cells.
The anticancer activity of trichostain A （TSA） on human B cell non-Hodgkin＇s lymphoma and its mechanism were explored, The effect of TSA on the growth of Raji cells and normal peripheral blood mononuclear cells （NPBMNC） was studied by MTr assay, The effect of TSA on the apoptosis of Raji cells and NPBMNC was studied by flow cytometry and TDT-mediated dUTP nick end labeling （TUNEL）. The effect of TSA on the cell cycle of Raji cells was studied by propidium iodide method. The results showed that TSA potently inhibited proliferation of Raji cells at microgram concentrations and induced apoptosis of Raji cells in a time-and concentration-dependent manner. Treatment with TSA induced accumulation of cells in G0/G1 or G2/M and a concomitant decrease of cell population in S phase. However, NPBMNC was less sensitive to the cytotoxic effect of TSA than Raji cells. It was concluded that TSA may inhibit the proliferation of Raji cells by regulating the cell cycle and inducing the cell apoptosis. Moreover, TSA demonstrates low toxicity in NPBMNC but selectively induces apoptosis of Raji cells.
Summary： To explore the anticancer effect of curcumin on human B cell non Hodgkin＇s lymphoma and compare its effects on human B cell non Hodgkin＇s lymphoma cells and normal peripheral blood mononuclear cells （NPBMNCs）. MTT assay was used to study the effect of curcumin on the growth of Raji cells and NPBMNCs. The effect of curcumin on the apoptosis of Raji cells and NPBMNC were studied by flow cytometry and TDT-mediated dUTP nick and labeling （TUNEL）. The effect of curcumin on the cell cycle of Raji cells were examined by propidium iodide staining flow cytometry. The results showed that curcumin strongly inhibited proliferation of Raji cells, 24 h IC50, for Raji cells was 22.8±1.82μmol/l, and curcumin induced Raji cell apoptosis in a time-and dose-dependent manner. Raji cells treated with curcumin showed G0/G1 or G2/M phase increase and S phase decrease. However, curcumin did not demonstrate apparent proliferation inhibition and apoptosis induction in NPBMNCs. It was concluded that curcumin is able to inhibit the proliferation of Raji cells by regulating the cell cycle and inducing the cell apoptosis. Morever, curcumin has low toxicity on NPBMNCs but can selectively induce apoptosis in Raji cells.
