Effect Of β1 Integrin On Proliferation, Migration And Sensitivity Of Non-Hodgkin's Lymphoma Cells And Modulatory Effects Of Curcumin

Part I. Study of the effects of curcumin on Raji cell[Objective] To study the anticancer activities of curcumin on Raji and and compare the effects of curcumin on Raji and normal peripheral blood mononuclear cell(NPBMNC).[Methods] The effect of curcumin on the growth of Raji cells and NPBMNC were studied through MTT assay, The effect of curcumin on the apoptosis of Raji cells and NPBMNC were studied by Annexin V/PI double-labeled flow cytometry. The effect of curcumin on the cell cycle of Raji cells were studied by a propidium iodide method.[ Results ] (1) Curcumin potently inhibited proliferation of Raji cells. (2) curcumin induced Raji cells apoptosis in a time- and dose-dependent manner. (3) Raji cells treated with curcumin showed G0/G1 or G2/M phase increase and S phase decrease. (4) NPBMNC were less sensitive to the cytotoxic effect of curcumin than Raji cells.[Conclusion] Curcumin is able to inhibit the proliferation of Raji cells by regulating the cell cycle and inducing the cell apoptosis. Morever, curcumin demonstrate low toxicity in NPBMNC but selectively induced apoptosis of Raji cells. Part II. β1 integrin expression in lymphoma and modulatory effect of curcumin[Objective] To investigate the expression of β1 integrin in lymphoma and modulatory effect of curcumin[Methods] Immunohistochemistry was used to detect β1 integrin expression in B-lymphoma, T-lymphoma and reactive hyperplasia lymph node. Flow cytometry and reverse transcriptase polymerase chain(RT-PCR) method were used to determine β1 integrin protein and mRNA level modulated by curcumin.[Results] (1)P1 integrin was highly expressed in Raji cells but lowly expressed in Daudi cells and normal B lymphocyte. (2)β1 integrin expression in T lymphoma and reactive hyperplasia lymph node were significantly lower than in B lymphoma lymph node.(3)Curcumin at low concentration can markedly inhibit the expression of β1 integrin.[Conclusion] β1 integrin was highly expressed in Raji cells but lowly expressed in normal lymphocyte and lymph node, which indicated β1 integrin was a promising target for anti-adhesion therapy. The expression level of β1 integrin in different type of lymphoma was different, which indicatedpi integrin was important for the differentiation diagnosis of lymphoma and research on anti-lymphoma effect of drug with β1 integrin as target will possess important value. Curcumin can markedly inhibit the expression of β1 integrin and may be a new drug inhibiting invasion and metastasis of lymphoma. Part III. Study on effect of curcumin on sensitivity of Raji cells to chemotherapy and its mechanism[Objective] To investigate the effects of FN/β1 integrin pathway on sensitivity of lymphoma cells to chemotherapeutic drugs and the effects and mechanisms of curcumin on increasing sensitivity of lymphoma cells .[Methods] MTT assay was used to study the inhibitory rate of proliferation of lymphoma cells in different groups(control, Cur, ADR, Cur+ADR, FN+ADR, FN + anti-integrin+ADR, Cur+FN +ADR) .The Jin's formula was used to analyze the effect of drug combination,[Results] Simultaneous administration of Curcumin combining with adriamycin produced a simple addition or potentiation effect. After cultured with FN, inhibitory rate of lymphoma cells decreased significantly (inhibitory rate 32.5%). After blocking β1 integrin combined with FN by anti-integrin antibody, inhibitory rate recovered. Inhibitory rate of lymphoma cells cultured with Curcumin, FN and adriamycin simultaneously is markedly higher than cultured with FN and adriamycin (inhibitory rate 59.2%, P<0.01).Conclusion FN/β1 integrin was involved in regulating sensitivity of lymphoma cells to adriamycin. Curcumin can increase the sensitivity of lymphoma cells to chemotherapeautic drugs by inhibiting the action of β1 integrin. Part IV. Modulatory effect of curcumin on the adhesion and migration of Raji cells[Objective] To study the effect of SDF1/CXCR4 and FN/β1 integrin modulated by curcumin on the adhesion and migration of B lymphoma Raji cell and to explore the mechanism of Raji inhibiting the invasiveness of lymphoma.[Methods] The experiment was classified into seven groups: Control, FN, SDF, FN+anti-β1 integrin, SDF+anti-CXCR4, curcumin+FN, curcumin+SDF. Adhsion assay and migration assay were used to detect the difference of invasiveness among different groups.[Results] In vitro, SDF1 and FN can increase the adhesion and migration of Raji cells which can be blocked by β1 integrin antibody and CXCR4 antibody. Curcumin can inhibit the adhesion and migration of Raji to FN in a dose-dependant manner. Low dosage curcumin had minimal effect on the adhesion and migration of Raji induced by SDF except that 25μmol/L curcumin can inhibit the adhesion and migration of Raji.[Conclusion] FN/β1 integrin and SDF1/CXCR4 play important role in the adhesion and migration of Raji cell. SDF1 can enhance the adhesion and migration of Raji cell through down-regulating β1 integrin. Curcumin can decrease the ability of invasiveness of Raji cell through inhibiting β1 integrin and SDF1/CXCR4 and has good prospect of clinical application.