Objective:To investigate the relationship between “activation of IL 6 signal transduction pathways” and “induction of CD45 expression” in a myeloma cell line—Sko 007 by IL 6.Methods:Electrophoretic mobility shift assay(EMSA) was used to detect the activation of the transcription facotrs STAT3 and NF IL 6 by IL 6,which can represent the activation state of the two IL 6 signal transduction pathways respectively;Then the induction of CD45 mRNA and protein expression by IL 6 were detected by RT PCR and FACS.The effect of antisense expression plasmid of STAT3 pAT STAT3 on STAT3 activation and CD45 expression was shown by EMSA and RT PCR,respectively.Results:①Both two IL 6 signal transduction pathways JAK/STAT and Ras/NF IL 6 can be activated by IL 6 in Sko 007 cells.②The expression level of CD45 mRNA and protein is Sko 007 cells can be up regulated by IL 6.③The activation of JAK/STAT signal transduction pathway and induction of CD45 mRNA expression by IL 6 can be inhibited in pAT STAT3 transfected Sko 007 cells.Conclusion:IL 6 induced CD45 expression in Sko 007 cells in mediated by the activation of JAK/STAT signal transduction pathway.

Objective:To investigate the mechanism of dexamethasone(DEX) induced apoptosis of human myeloma cell line Sko 007 and the inhibitory effect of IL 6 on apoptosis.Methods:Effect of DEX on the growth of Sko 007 cells was measured by MTT assay;Apoptosis of Sko 007 cells induced by DEX was determined by flow cytometry with propidium iodide(PI) staining of nuclei;The expression of three anti apoptotic Bcl 2 family proteins Bcl 2,Bcl X L and Mcl 1 in Sko 007 cells with or without DEX were determined by immunblot assay.Results:DEX inhibited the proliferation of Sko 007 cells and induced a significant cell apoptosis.In addition,degradation of Bcl 2 can be observed in Sko 007 cells in the presence of Dex.IL 6 stimulation prevented down regulation of Bcl 2 and the apoptosis of Sko 007 cells induced by DEX.Conclusion:IL 6 inhibits DEX induced apoptosis of Sko 007 cells through the specific regulation of Bcl 2.

OBJECTIVETo investigate the biological activity and molecular mechanism of interferon alpha (IFNalpha) on human myeloma cell line Sko-007.

METHODSThe effect of IFNalpha on the growth of Sko-007 cells was measured by MTT assay. Cells cycle distribution and the expression of two IL-6 receptor chains (IL-6R and gp130) on Sko-007 cell surface in the absence or presence of IFNalpha were monitored by FACS analysis. The activation state of protein kinase ERK, which is involved in Ras/MAPK signal transduction pathway mediating cell survival and proliferation, and the expression of anti-apoptotic Bcl-2 family proteins-Bcl-2, Bcl-x(L) and Mcl-1 in Sko-007 cells with or without IFNalpha were determined by immunoblot assay.

RESULTIFNalpha arrested Sko-007 cell cycle progression. After stimulation with IFNalpha, an obvious increase in G(0)/G(1) phase (41.1%-->84.1%) and decrease in S phase (57.1%-->13.3%) of Sko-007 cell cycle distribution can be observed. Moreover, the proliferation of Sko-007 cells was dramatically inhibited in the presence of IFNalpha, with a maximal inhibitory rate up to 88%. In addition, the expression of gp130 on cell surface, the activation of protein kinase ERK and the expression of Bcl-2 and Bcl-x(L) were all down-regualted in IFNalpha-stimulated Sko-007 cells.

CONCLUSIONThe inhibitory effect of IFNalpha on the proliferation of Sko-007 cells was mediated by gp130 down-regulation, degradation of Bcl-2 family anti-apoptotic proteins and inhibition of ERK activation.

Antigens, CD ; drug effects ; metabolism ; Cell Cycle ; drug effects ; Cell Division ; drug effects ; Cytokine Receptor gp130 ; Dose-Response Relationship, Drug ; Down-Regulation ; Enzyme Activation ; drug effects ; G1 Phase ; drug effects ; Humans ; Immunoblotting ; Interferon-alpha ; pharmacology ; Membrane Glycoproteins ; drug effects ; metabolism ; Mitogen-Activated Protein Kinases ; metabolism ; Multiple Myeloma ; metabolism ; pathology ; Proto-Oncogene Proteins c-bcl-2 ; metabolism ; Receptors, Interleukin-6 ; drug effects ; metabolism ; Resting Phase, Cell Cycle ; drug effects ; S Phase ; drug effects ; Tumor Cells, Cultured ; drug effects ; metabolism ; bcl-X Protein

OBJECTIVETo investigate apoptosis in XG-7, a human myeloma cell line, induced by IL-6 deprivation and the function of three anti-apoptotic Bcl-2 proteins (Bcl-2, Bcl-kappa(L), Mcl-1) in the apoptotic process.

METHODSApoptosis in XG-7 myeloma cells induced by IL-6 withdrawal was determined by flow cytometry with propidium iodide (PI) nuclear staining. Expressions of three Bcl-2 proteins in XG-7 cells were monitored by immunoblotting assay.

RESULTSIn the absence of IL-6 for a certain time, a significant percentage of apoptiotic XG-7 cells can be observed, as well as down-regulated expression of one of the three anti-apoptotic proteins (Mcl-1) in XG-7 cells. IL-6 re-stimulation in XG-7 cells following cytokine removal up-regulated the expression of Mcl-1 and inhibited cell apoptosis.

CONCLUSIONMcl-1,instead of Bcl-2 and Bcl-kappa(L), plays an important role in IL-6 deprivation induced apoptosis in XG-7 human myeloma cells.

Apoptosis ; Humans ; Interleukin-6 ; physiology ; Multiple Myeloma ; pathology ; Myeloid Cell Leukemia Sequence 1 Protein ; Neoplasm Proteins ; analysis ; physiology ; Proto-Oncogene Proteins c-bcl-2 ; analysis ; Tumor Cells, Cultured ; bcl-X Protein

The key to killing target cells by immunotoxin depends on the specific recognition of antibody to target cell and the cytotoxic effect of toxin. The comparative study of the killing effects of two anti-T immunotoxins, CD5:Ricin and CD5:rRA, on target cells was performed. The elimination rate of immunotoxins was analysed by flow cytometry and MLR. The effect of immunotoxins on the proliferation of hematopoiesis was evaluted by CFU-GM. The results showed that (1) CD5(+) T cells were eliminated and CD25(+) CD3(+) activated T cells were concentration-dependently inhibited by the two immunotoxins in the range of 10(-9) - 10(-11) mol/L; (2) both immunotoxins significantly inhibited the mixed lymphocyte reaction, and the inhibiting effect of CD5:rRA to T cell proliferation was markedly lower than that of CD5:Ricin in the range of 10(-10) - 10(-11) mol/L; (3) the combination of CD5:rRA with 10 mmol/L NH(4)Cl increased the T cell elimination rate; and (4) the two immunotoxins and the combination of NH(4)Cl and CD5:rRA did not suppressed proliferation of granulocyte-macrophage progenitors in the range of concentrations with killing effect. It was concluded that T cell and activated T cell could be eliminated effectively by immunotoxins, the proliferation of granulocyte-macrophage progenitor was not inhibited significantly.

To study the reconstituion of the T-cell populations after allogeneic hematopoietic stem cell transplantation, the peripheral blood samples obtained at different time points post-transplantation in 21 patients were analyzed using CD5-PE and CD3-FITC with flow cytometry. During the first 3 months after transplantation, CD3(-) CD5(+) T cell subsets, representing early thymocytes, remained below normal level, whereas CD3(+) CD5(+) T cell subsets, representing mature T cells, regenerated to normal level. In 9 patients who developed acute graft-versus-host disease (GVHD), the percentage of CD3(+) CD5(+) T cell subsets was significantly higher than that in patients who did not develop acute GVHD (P < 0.05). These results demonstrated that the early recovery of T cells is mainly due to the expansion of mature T cell populations, and the over-expansion of mature T (CD3(+) CD5(+)) cells is responsible for the development of acute GVHD.