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 re...

background: heme oxygenase-1 (ho-1) is a cytoprotective and antiapoptotic enzyme, which has been involved in maintaining cellular homeostasis, and plays an important protective role by modulating oxidative injury. up-regulation of (ho-1) has contributed to tumorogenicity of some cancers. in this study we investigated the expression pattern of the ho-1, in five different human-derived cancer cel...

background: human peripheral blood nk cells constitutively express cd56 and cd16 antigens. peripheral blood nk cells seem to be strongly related with decidual nk cells, and may reflect the decidual nk cell functional status. there are varied reports concerning the relationship between nk cell cytotoxicity in women with recurrent spontaneous abortion. objective: to study nk activity in women wit...

Background: Human peripheral blood NK cells constitutively express CD56 and CD16 antigens. Peripheral blood NK cells seem to be strongly related with decidual NK cells, and may reflect the decidual NK cell functional status. There are varied reports concerning the relationship between NK cell cytotoxicity in women with recurrent spontaneous abortion. Objective: To study NK activity in women wit...

Human erythroid-potentiating activity (EPA) is a 28,000 mol wt glycoprotein that stimulates the growth of erythroid progenitors in vitro and enhances colony formation by the K562 human erythroleukemia cell line. EPA has potent protease inhibitory activity, and is also referred to as tissue inhibitor of metalloproteinases (TIMP). We observed that colony formation by K562 cells in semi-solid medi...

Cells of the proerythromyeloid cell line K562 and of the T cell line Jurkat were able to induce an increase in TNF-, IL1 alpha-, and IL1 beta-mRNA expression in human peripheral blood derived monocytes in vitro. The activating principle of these tumor cells was associated with fractions of membrane preparations of distinct molecular mass, 32-38 kD for Jurkat cells and 46-54 kD for K562 cells, r...

In addition to its inhibitory activity against viral DNA polymerases and reverse transcriptase, the acyclic nucleoside phosphonate 9-(2-phosphonylmethoxyethyl)adenine (PMEA) also markedly inhibits the replicative cellular DNA polymerases alpha, delta, and epsilon. We have previously shown that PMEA is a strong inducer of differentiation in several in vitro tumor cell models and has marked antit...

OBJECTIVE To screen the anti-tumor fraction of ethanol extracts from Thymus quinquecostatus Celak and investigate its anti-tumor effect on human leukemia cell line. METHODS Ethyl acetate, n-butanol and acetone fractions were separated from the ethanol extracts of wild Thymus quinquecostatus Celak. Growth inhibiting effects of these extracts on human leukemia cell lines K562 and HL-60 were det...

Background: Heme oxygenase-1 (HO-1) is a cytoprotective and antiapoptotic enzyme, which has been involved in maintaining cellular homeostasis, and plays an important protective role by modulating oxidative injury. Up-regulation of (HO-1) has contributed to tumorogenicity of some cancers. In this study we investigated the expression pattern of the HO-1, in five different human-derived cancer cel...