Effects of Triptolide on Cell Proliferation and CXCR4 Expression in Burkitt’s Lymphoma Raji Cells In Vitro

Objective： To investigate the inhibitory effects of triptolide on cell proliferation and CXCR4 expression in Burkitt＇s lymphoma cell line Raji cells. Methods： The effects of triptolide on the growth of Raji cells were studied by 3-（4, 5-Dimethyl-2-thiazolyl）-2, 5-diphenyl-2H-tetrazolium（MTT） assay. The effects of triptolide on CXCR4 expression on Raji cells were studied by flow cytometric analysis. Chemotaxis assays were performed to observe the effects of triptolide on migration of Raji cells towards recombinant human SDF-1α （rhSDF-1α） in vitro. Results： Triptolide inhibited the proliferation of Raji cells in a dose- and time-dependent way with a 24-h IC50 value of 43.06 nmol/L and a 36-h IC50 value of 25.08 nmol/L. Triptolide could downregulate the CXCR4 expression on Raji cells in a dose-dependent manner. Furthermore, chemotaxis assays showed that triptolide could block the migration of Raji cells to rhSDF-1α in vitro, and the inhibition was dose-dependent. Conclusion： Triptolide could inhibit the proliferation and migration of Raji cells in vitro. The underlying anti-tumor mechanism of triptolide might be related to the anti-proliferative effect and the blockage of SDF-1/CXCR4 axis.

GROWTH-INHIBITORY EFFECTS OF CURCUMIN ON Raji CELLS AND ITS MECHANISMS

Objective： To study the growth-inhibitory effects of curcumin on B-NHL cell line Raji cells in vitro and its molecular mechanisms. Methods： The growth inhibition rates of Raji cells, after being treated with 6.25μmol/L - 50μmol/L curcumin for 12 h - 48 h, were examined by MTT assay. The apoptosis rate was detected by flow cytometry （FCM）, the protein expression levels of bcl-2 and p53 in Raji cells were examined by SP immunohistochemistry. The expression of p53 in Raji cell were checked by RT-PCR. Results： After being treated by various concentrations of curcumin, the growth of Raji cells was inhibited significantly. The rates of apoptosis were 11.8% -79.7% （P〈0.01）, the down regulation of p53 expression was observed within 24 h after the treatment of curcumin by RT-PCR. The expression of bcl-2 and p53 was decreased, which depended on the action time. Conclusion： Curcumin could significantly inhibit the growth of Raji cells. The induction of apoptosis by down-regulating the expression of bcl-2 and p53 was probably one of its molecular mechanisms.

ENHANCEMENT OF RADIATION-INDUCED APOPTOSIS IN RAJI CELL LINE BY BC1-2 ANTISENSE OLIGODEOXYNUCLEOTIDE

Objective: To investigate whether the Bc1-2 antisense oligonucleotide(ASODN) may enhance radiation-induced apoptosis in Raji cell line. Methods: Cell surviving fraction was determined using the trypan blue dye exclusion assay. The expression level of bc1-2 protein was assayed by immunofluorescence using fluoresce isothiocyanate label. Apoptosis was detected by Giemsa staining and flow cytomertric cell cycle analysis. Results: It was found that Bc1-2 ASODN combined with radiation had significantly reduced the number of viable cells (P<0.05). There was no difference on cell survival between mismatch Bc1-2 oligodeoxynucleotide/radiation combination and radiation-treated cells alone. Bc1-2 ASODN combined with radiation could significantly inhibit expression of Bc1-2 protein in Raji cells (P<0.05). Cells treated with Bc1-2 ASODN combined with radiation at 72 h displayed classic apoptotic changes. Apoptosis rates of Raji cells treated with Bc1-2 oligodeoxynucleotide/radiation combination and radiation-treated cells alone, respectively. Conclusion: Bc1-2 antisense oligonucleotide can enhance radiation-induced apoptosis in Raji cell line.

Anticancer Activities of Trichostatin A on Maligant Lymphoid 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.

Anticancer Effect of Curcumin on Human B Cell non-Hodgkin's Lymphoma

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.