ABSTRACT
We report here the time-course of electron microscopic changes induced by gamma-interferon (IFN-gamma) in the human erythromyeloid leukemia cell line K562. In K562 cells treated with IFN-gamma for 6h, the nuclei were polygonal in shape and microvilli were far more abundant on cell membranes compared with control K562 cells, and invaginations were often seen in the cell membranes. There was a reduction in the number of cell-membrane microvilli and an increase in the number of lysosomal bodies in the cytoplasm of K562 cells treated with IFN-gamma for 12h. After treatment with IFN-gamma for 24h, the cell membrane microvilli disappeared, large numbers of cellular organelles were observed, such as mitochondria and lysosomes, and the cytoplasm became electron-dense. Cytoplasmic vesicles and vacuoles were also observed. These vesicles may correspond to an intermediate step in the ultimate cellular disintegration associated with apoptosis caused by IFN-gamma.
Subject(s)
Apoptosis/drug effects , Interferon-gamma/pharmacology , Monocytes/ultrastructure , Cell Division/drug effects , Cell Nucleus/drug effects , Cell Nucleus/ultrastructure , Cell Survival/drug effects , Humans , Microscopy, Electron , Microvilli/drug effects , Microvilli/ultrastructure , Monocytes/drug effects , Organelles/drug effects , Organelles/ultrastructure , Time Factors , Tumor Cells, CulturedABSTRACT
We investigated the effect of gamma-interferon (gamma-IFN) on three cellular parameters: cell membrane fluidity and expression of two antigens that have been associated with cell proliferation, namely transferrin receptor (Tf-R: a cell surface protein) and Ki-67 antigen (Ki-67: a nuclear protein). We observed small, yet significant changes in the first two parameters, but not the third parameter. These were investigated in K562 cells, a human chronic myelocytic leukemia cell line. These results suggest that the microviscosity changes and the surface Tf-R density were closely associated, and that gamma-IFN was involved in increasing proliferative activity of the cells by decreasing membrane fluidity and upregulating Tf-R expression.
Subject(s)
Interferon-gamma/pharmacology , Membrane Fluidity/drug effects , Receptors, Transferrin/metabolism , Up-Regulation/drug effects , Cell Division/physiology , Humans , Ki-67 Antigen , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/metabolism , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/pathology , Neoplasm Proteins/drug effects , Neoplasm Proteins/metabolism , Nuclear Proteins/drug effects , Nuclear Proteins/metabolism , Receptors, Transferrin/drug effects , Tumor Cells, Cultured/drug effects , ViscosityABSTRACT
The time-course of changes in the plasma-membrane lipid bilayer induced by tumour necrosis factor-alpha (TNF) were investigated in cultured cells using spin-label electron-spin-resonance techniques. Treatment of K 562 cells, a human chronic myelocytic leukaemia cell line, in suspension culture with TNF for up to 6 h caused an initial increase in cell-membrane fluidity, which returned to the control level after 12 h of treatment. After 24 h of treatment, the cell-membrane fluidity had decreased and this decrease was maintained after 48 h of treatment. In Daudi cells, a human malignant lymphoma cell line, TNF, did not induce any changes in cell-membrane fluidity, indicating that the effect of TNF on membrane structure is cell-specific. The early and transient change in membrane fluidity in K 562 cells is probably related to signal generation, while the later, persistent change may reflect the phenotype of TNF-treated cells, in particular, changes in the plasma membrane-cytoplasmic complex. Histochemical electron microscopic studies indicated that the membrane fluidity changes induced by TNF have an ultrastructural correlate.
Subject(s)
Cell Membrane/drug effects , Tumor Necrosis Factor-alpha/pharmacology , Electron Spin Resonance Spectroscopy , Humans , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/metabolism , Lymphoma/metabolism , Membrane Fluidity/drug effects , Microscopy, Electron , Time Factors , Tumor Cells, CulturedABSTRACT
Using flow cytometry, we evaluated the effect of extracellular pH on intracellular retention of adriamycin (ADR) in K562 cells. The intracellular retention of ADR at pH 7.60 increased markedly compared to the level at pH 7.30. The cell membrane fluidity was measured by spin labeled electron spin resonance techniques. The cell membrane fluidity at pH 7.60 decreased significantly in comparison with those at pH 7.45 and 7.30. The antiproliferative effect of ADR at pH 7.60 was significantly augmented compared to those at pH 7.45 and 7.30. These results suggested that the augmentation of ADR-induced antiproliferative effect by extracellular alkalic shift was caused by membrane rigidity of lipid bilayer, resulting in the decrease of ADR efflux due to less function of P-glycoprotein.
Subject(s)
Doxorubicin/pharmacokinetics , Extracellular Space/metabolism , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/pathology , Membrane Fluidity , Electron Spin Resonance Spectroscopy , Humans , Hydrogen-Ion Concentration , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/metabolism , Tumor Cells, Cultured/metabolismABSTRACT
Cell membrane fluidity (CMF) and transferrin receptor (Tf-R) expression were investigated in K562 cells, a human chronic myelocytic leukemia cell line, treated by gamma-interferon (IFN-gamma). CMF was increased using spin-labeled electron spin resonance techniques, and Tf-R expression was measured by flow cytometric analysis with an EPICS-750 flow cytometer/cell sorter. Treatment of K562 cells in suspension culture with IFN-gamma for as long a time as 6 hr caused an increase in CMF, and then returned to the level of control cells at 12 hr. Conversely, by 24 hr after the beginning of treatment, the rigidity of CMF was increased. Thus, the changes of IFN-gamma-induced CMF was biphasic. While the early change of CMF is related to signal generation and transmission, the later change may reflect changes in lipid compositions and/or cytoskeletal complexes of the plasma cell membrane. A significant increase of Tf-R after 6 hr and 24 hr in number was obtained by treatment of K562 cells with IFN-gamma, but at 12 hr the number of Tf-R did not differ from the control. These results suggested that the early phase of upregulation of Tf-R induced by IFN-gamma was caused by increased CMF, and the late phase of upregulation of Tf-R was due to increased rigidity of CMF. In conclusion, the state of CMF associated with a certain receptor expression in cells is not rigid and can be modulated to some extent by exogenous influences. This may open possibilities of some adjuvant therapeutic measures in malignant diseases by increasing the antigenicity of tumor cells.
Subject(s)
Leukemia, Myelogenous, Chronic, BCR-ABL Positive/pathology , Membrane Fluidity , Receptors, Transferrin/metabolism , Cell Membrane/metabolism , Cell Membrane/physiology , Electron Spin Resonance Spectroscopy , Flow Cytometry , Humans , Interferon-gamma/pharmacology , Kinetics , Lipid Bilayers/metabolism , Spin Labels , Tumor Cells, Cultured , Up-RegulationABSTRACT
The incubation of K562 cells with adriamycin resulted in a decrease in cell membrane fluidity as measured by electron spin resonance using the paramagnetic probe 5-doxylstearic acid. Coincidently, the antiproliferative effect of adriamycin was progressively inhibited as the concentration of adriamycin was increased. The results indicate that adriamycin induces changes in the plasma membrane of K562 cells after exposure to a low level of this agent.
Subject(s)
Doxorubicin/pharmacology , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/pathology , Membrane Fluidity/drug effects , Cyclic N-Oxides , Electron Spin Resonance Spectroscopy , Humans , Spin Labels , Tumor Cells, CulturedABSTRACT
The anti-proliferative effects of tumour necrosis factor-alpha (TNF-alpha) and interferon-alpha (IFN-alpha), alone or in combination, on human pancreatic cancer cells lines (PANC-1, MIA PaCa-2 and BxPC-3) and human pancreatic cancer tumour (Exp-58), were investigated in vitro and in vivo. The anti-proliferative effect was determined using the dye uptake method and the subcutaneous tumour model. Combined TNF-alpha and IFN-alpha demonstrated marked synergistic and/or additive effects in comparison with their effects as single agents. These results suggest that combined cytokine therapy of TNF-alpha and IFN-alpha may make possible some improvement in the treatment of pancreatic carcinoma patients in the future.
Subject(s)
Interferon-alpha/pharmacology , Pancreatic Neoplasms/therapy , Tumor Necrosis Factor-alpha/pharmacology , Animals , Cell Division/drug effects , Drug Screening Assays, Antitumor , Drug Synergism , Humans , In Vitro Techniques , Male , Mice , Mice, Nude , Neoplasm Transplantation , Pancreatic Neoplasms/pathologyABSTRACT
A 56 year-old rectal cancer patient who developed a chronic rectoabdominocutaneous fistula postoperatively was treated with fibrin clot, and the fistula healed completely. Occlusion of chronic postoperative fistulas with fibrin clot appears to be a useful technique.
