SEARCH · Search PubMed

Results for “K562 Cells”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources

PubMed1985

Trans acting regulation of beta globin gene expression in erythroleukemia (K562) cells.

K562 cells are induced by hemin to produce gamma and epsilon globin but not beta globin, although the beta globin gene is intact, and when isolated is expressed in a transient expression assay (1, 2). We have previously shown that an epsilon globin gene transferred into K562 cells is expressed and inducible (3). In this paper, we report the stable transfer of a sickle or betaS globin gene into K562 cells. Thirty-six different transformed lines were tested; 24 of 36 lines contained an intact betaS globin gene. However, using S1 nuclease, Dot blot, and Northern blotting analyses, none of these lines showed beta globin mRNA expression. These results indicate that trans acting factors are responsible for the lack of expression of the beta globin gene in K562 cells.

Cell Line↗

PubMed2004

[CML cell line K562 cell apoptosis induced by mangiferin].

This study was aimed to investigate the effects and the mechanism of mangiferin on chronic myeloid leukemia cell lines K562 cells in vitro. The antiproliferation effects of mangiferin on K562 leukemia cells were tested by tetrazolium salt (MTT) method; the apoptosis induced by mangiferin on K562 cell line was explored by means of cell morphology, DNA gel electrophoresis and flow cytometry. The changes in bcr/abl gene expression was detected by using reverse transcriptase (RT)-PCR. The results showed that five different concentrations of mangiferin (25 - 200 micromol/L) dose-dependently and time-dependently inhibited the proliferation of K562 cells, and induced apoptosis in K562 cell line. RT-PCR revealed that bcr/abl gene expression was down-regulated when K562 cells had been treated with different concentrations of mangiferin. In conclusion, mangiferin remarkably inhibits the proliferation of K562 leukemia cells in vitro, and induces apoptosis in K562 cell line probably through down-regulation of bcr/abl gene expression.

Apoptosis↗

PubMed1991

Regulation of Cu,Zn superoxide dismutase with copper. Caeruloplasmin maintains levels of functional enzyme activity during differentiation of K562 cells.

K562 cells, a human erythroleukaemic cell line blocked for differentiation, commit towards erythrocytes when exposed to haemin (20 microM). The cells synthesize fetal haemoglobins and show site-specific binding of caeruloplasmin, a plasma copper protein. These events are set into motion by haemin. On the assumption that the binding of caeruloplasmin could reflect a greater need for copper, we sought to determine whether the transfer of 67Cu from caeruloplasmin was accelerated in haemin-induced compared with non-induced K562 cells. Cu,Zn superoxide dismutase (CuZnSOD) was the recipient. Haemin induction caused the K562 cells to lose CuZnSOD activity. By 96 h, the level of SOD activity was less than 60% of that of non-induced cells. The loss was confined entirely to the CuZn form, MnSOD activity staying essentially unchanged. Although CuZnSOD activity declined with the haemin induction, the incorporation of [4,5-3H]lysine into immunoprecipitable CuZnSOD protein was unaffected. There was also no change in CuZnSOD mRNA concentration in haemin-induced cells. Thus a loss of enzyme did not correlate with a decline in the synthesis de novo of CuZnSOD protein. When 48 h-induced cells were transferred to a medium supplemented with 0.2 microM-caeruloplasmin, CuZnSOD activity was restored to control levels in 24 h. Caeruloplasmin also stimulated the incorporation of [3H]lysine into immunoprecipitable CuZnSOD protein. Caeruloplasmin addition may have affected a post-translational regulatory site for CuZnSOD biosynthesis, possibly by providing copper for the newly synthesized enzyme.

Biological Transport↗

PubMed1987

Expression of human gamma-globin genes in human erythroleukemia (K562) cells.

K562 cells express embryonic (epsilon) and fetal (gamma) globins and hemoglobins but not adult (beta) globin. To define the cis acting regulatory elements involved in the discrimination between gamma and beta genes, we have constructed chimeric genes composed of portions of gamma and beta and evaluated their expression in stable K562 transfectants. A gamma beta fusion gene containing gamma 5' sequences to the EcoRI site in exon 3 and beta sequences 3' is expressed at 10-40% that of the endogenous gamma level. In 50% of the lines, this fusion gene appropriately increases its expression in response to hemin, an inducer of endogenous globin gene expression in K562 cells. In contrast, a beta gamma fusion gene, containing beta sequences 5' to the EcoRI site in exon 3 and gamma sequences 3', is neither expressed nor correctly initiated. A beta gene containing gamma-intervening sequence (IVS) 2 accumulates an mRNA transcript when analyzed with a 3' beta probe. However, no correctly initiated beta mRNA is observed. A gamma gene with beta-IVS 2 is only inducible in one of six expressing clones. All the results are consistent with the presence of stage-specific trans acting factors in K562 cells that stimulate expression of gamma genes and suggest a significant role for gamma-IVS 2 in gamma gene expression.

Cell Line↗

PubMed1994

Altered stability of etoposide-induced topoisomerase II-DNA complexes in resistant human leukaemia K562 cells.

K562 leukaemia cells were selected for resistance using 0.5 microM etoposide (VP-16). Cloned K/VP.5 cells were 30-fold resistant to growth inhibition by VP-16 and 5- to 13-fold resistant to m-AMSA, adriamycin and mitoxantrone. K/VP.5 cells did not overexpress P-glycoprotein; VP-16 accumulation was similar to that in K562 cells. VP-16-induced DNA damage was reduced in cells and nuclei from K/VP.5 cells compared with K562 cells. Topoisomerase II protein was reduced 3- to 7-fold and topoisomerase II alpha and topoisomerase II beta mRNAs were each reduced 3-fold in resistant cells. After drug removal, VP-16-induced DNA damage disappeared 1.7 times more rapidly and VP-16-induced DNA-topoisomerase II adducts dissociated 1.5 times more rapidly in K/VP.5 cells than in K562 cells. ATP (1 mM) was more effective in enhancing VP-16-induced DNA damage in nuclei isolated from sensitive cells than in nuclei from resistant cells. In addition, ATP (0.3-5 mM) stimulated VP-16-induced DNA-topoisomerase II adducts to a greater extent in K562 nuclei than in K/VP.5 nuclei. Taken together, these results indicate that resistance to VP-16 in a K562 subline is associated with a quantitative reduction in topoisomerase II protein and, in addition, a distinct qualitative alteration in topoisomerase II affecting the stability of drug-induced DNA-topoisomerase II complexes.

Antineoplastic Agents↗

PubMed2006

[Correlation of NK cell activity against autologous tumour cells and K562 cells with the clinical outcome during therapy with mistletoe extracts].

BACKGROUND: Suppression of NK cell activity is considered to be an unfavourable prognostic factor for tumour progression. There is proof that mistletoe extracts may increase NK cell activity. However, the inverse relation between an increase of NK cell activity and clinical progress of cancer has not been investigated. AIM AND DESIGN: The relation of NK cell activity and progress of cancer in patients under therapy with mistletoe extracts was examined in a prospective, monocentric, cohort study. At the same time the in vitro killing of K562 cells and autologous tumour cells was compared. PATIENTS AND METHODS: 40 patients with operable cancer of the breast or colon were included. The patients did not receive any immunologically relevant therapies except for mistletoe extracts. The absolute NK cell count in peripheral blood as well as the in vitro NK cell activity were monitored for up to 2 years and compared with clinical outcome as well as quality of life. RESULTS: The absolute NK cell count in peripheral blood increased within the observation period. Patients without progression had a significantly higher mean activity of NK cells against K562 cells than patients with progression. In the latter group, only stage IV patients showed reduced NK cell activity. The killing activity against autologous tumour cells was <5% in about 77.5% of the patients and could not be evaluated further. The NK cell activity against K562 cells was not related to the number of NK cells. CONCLUSIONS: We found a relation between NK cell activity and the progression of malignant disease. In further studies the causality of this relation has to be clarified. The establishment of NK cell activity against autologous tumour cells as a suitable parameter during follow-up was not successful.

Aged↗

PubMed1999

3'-Azido-3'-deoxythymidine reduces the rate of transferrin receptor endocytosis in K562 cells.

K562 cells, exposed for at least 24 h to 5 microM 3'-azido-3'-deoxythymidine (AZT), gave rise to an overall increase in the number of cell surface transferrin binding receptors (18-20%). This effect was ascertained either with binding experiments by using 125I-transferrin and with immunoprecipitation by using a specific monoclonal antibody against the transferrin receptor. At higher AZT concentrations (20 and 40 microM), a further increase was found, that is, up to 23% by binding experiments and up to 110% by immunoprecipitation. However, Scatchard analysis of the binding data indicated that although the number of cell surface transferrin receptors increased, the affinity of transferrin for its receptor did not change (Ka=4.0x108 M). Surprisingly, immunoprecipitation of total receptor molecules showed that the synthesis of receptor was not enhanced by the drug treatment. The effect of AZT on transferrin internalization and receptor recycling was also investigated. In this case, data indicated that the increase in the number of receptors at the cell surface was probably due to a slowing down of endocytosis rate rather than to an increased recycling rate of the receptor to cell surface. In fact, the time during which half the saturated amount of transferrin had been endocytosed (t1/2) was 2.15 min for control cells and 3.41, 3.04, and 3.74 min for 5, 20, and 40 microM AZT-treated cells, respectively. Conversely, recycling experiments did not show any significant differences between control and treated cells. A likely mechanism through which AZT could interfere with the transferrin receptor trafficking, together with the relevance of our findings, is extensively discussed.

Carbon Radioisotopes↗

PubMed2005

[Study on rapid generation of dendritic cells from K562 cell line induced by A23187 alone].

OBJECTIVE: To explore a simple, rapid and efficient way to generate dendritic cells from leukemic cells. METHODS: K562 cells were cultured with calcium ionosphere A23187 alone, A23187 plus GM-CSF, or a DC differentiation cocktail consisting of GM-CSF, IL-4 and TNF-alpha, respectively. The expression of surface markers of induced DCs was analyzed by flow cytometry. The K562-DCs stimulating the proliferation of allo-genetic naive T cells and inducing cytotoxicity of T cells were determined by MTT assay. RESULTS: Microscopic examination revealed that under all the three culture conditions, K562 cells became displaying DC morphology. At 72 hours in the two culture systems containing A23187, there were higher proportions of cells with dendritic morphology [(69.5 +/- 17.2)% and (73.1 +/- 13.9)%, respectively] than that in the cocktail system [(28.5 +/- 12.3)%] (P < 0.05). And the same did when cultured for 7 days [(69.5 +/- 17.2)%, (73.1 +/- 13.9)% respectively vs (51.2 +/- 10.7)%, P < 0.05]. In the 7-day cultures, the percentage of CD1a expressing cells was lower [(8.2 +/- 2.3)% and (10.3 +/- 5.1)% vs (17.2 +/- 1.6)%, respectively] while the CD83 expressing cells was higher [(85.6 +/- 8.8)% and (82.4 +/- 9.1)% vs (77.4 +/- 12.9)%, respectively] compared with that in the cocktail system (P < 0.05). No significant difference was found in the allogeneic T cell proliferation response and induced T cell cytotoxicity between A23187 containing and cocktail groups (P > 0.05). CONCLUSIONS: A23187 treatment is a simple, rapid and efficient in vitro strategy for inducing dendritic cell from leukemic cells.

Calcimycin↗

PubMed1991

Ganglioside GM3 can induce megakaryocytoid differentiation of human leukemia cell line K562 cells.

The role of acidic glycosphingolipids in cell growth and differentiation was investigated using the multipotent leukemia cell line K562. When GM3 was added to cell culture media, the growth of K562 cells was remarkably inhibited and the cells were shown to have megakaryocytoid morphology. Ultrastructural study demonstrated that K562 cells treated with GM3 had platelet peroxidase-positive structures, which were considered to be the specific marker of megakaryocyte. Furthermore, AP-3 directed against an epitope present on membrane glycoprotein IIIa reacted with the GM3-treated cells. Free N-acetylneuraminic acid, GM1, GM2, GD1a, and a mixture of bovine brain gangliosides containing GD1a and GT1b did not affect growth of K562 cells or show morphological changes. According to chemical analyses, GM3 content increased in megakaryocytoid differentiation induced by tetradecanoylphorbol-13-acetate, whereas GM3 decreased in erythroid differentiation induced by hemin. Enzymatic analysis showed that the GM3 increase during megakaryocytoid differentiation was a result of the sialyltransferase activation. These results indicated that exogenous GM3 induced differentiation of K562 cells into a "GM3-rich" lineage, i.e., mainly megakaryocytoid lineage, and that GM3 accumulation in the GM3-rich lineage was the result of the activation of GM3 synthase. These findings strongly suggested that GM3 ganglioside, a minor membrane component, has a crucial role in not only the differentiation induction but also the determination of the differentiation direction in pluripotent K562 cells.

Cell Differentiation↗

PubMed2006

Photodynamic treatment (ALA-PDT) suppresses the expression of the oncogenic Bcr-Abl kinase and affects the cytoskeleton organization in K562 cells.

K562 is the chronic myelogenous leukemia (CML)-derived cell line that expresses high levels of chimeric oncoprotein Bcr-Abl. The deregulated (permanent) kinase activity of Bcr-Abl leads to continuous proliferation of K562 cells and their resistance to the apoptosis promotion by conventional drugs. The photodynamic treatment (PDT) based on the application of 5-aminolevulinic acid (ALA) and irradiation with blue light (ALA-PDT) resulted in the suppression of K562 cells proliferation. It was followed by a necrosis-like cell death [K. Kuzelová, D. Grebenová, M. Pluskalová, I. Marinov, Z. Hrkal, J. Photochem. Photobiol. B 73 (2004) 67-78]. ALA-PDT led to the perturbation of the Hsp90/p23 multichaperone complex of which the Bcr-Abl is the client protein. Bcr-Abl protein was suppressed whereas the bcr-abl mRNA level was not affected. Further on, we observed several changes in the cytoskeleton organization. We detected ALA-PDT-mediated disruption of filamental actin structure using FITC-Phalloidin staining. In connection with this we uncovered certain cytoskeleton organizing proteins involved in the cell response to the treatment. Among these proteins, Septin2, which plays a role in maintaining actin bundles, was suppressed. Another one, PDZ-LIM domain protein 1 (CLP36) was altered. This protein acts as an adaptor molecule for LIM-kinase which phosphorylates and thus inactivates cofilin. Cofilin was indeed dephosphorylated and could thus be activated and operate as an actin-depolymerizing factor. We propose the scheme of molecular response of K562 cells to ALA-PDT.

Aminolevulinic Acid↗

PubMed1993

Alternative route for the biosynthesis of polyunsaturated fatty acids in K562 cells.

K562 human leukaemia cells lack a significant delta 6-desaturase activity. However, they synthesize long-chain polyunsaturated fatty acids (PUFA) from linoleic (C18:2(9,12)) and linolenic (C18:3(9,12,15)) acids, by reactions involving a C2 chain elongation followed by a delta 5-desaturation step and, to some extent, a further elongation. The main products formed were separated by argentation t.l.c. and identified by g.l.c. as the uncommon fatty acids C20:3(5,11,14) and C20:4(5,11,14,17) respectively. These acids were also produced when cells were supplemented with C20:2(11,14) or C20:3(11,14,17) respectively. The presence of a delta 5-desaturase was further confirmed by using its corresponding normal substrates, C20:3(8,11,14) and C20:4(8,11,14,17), which led to C20:4(5,8,11,14) and C20:5(5,8,11,14,17) respectively. On the other hand, a high delta 9-desaturase activity, but no significant delta 4-desaturase activity, were detected in K562 cells. These results indicate the existence of an alternative pathway, involving delta 5-desaturase, which is the only route for PUFA biosynthesis in K562 cells. This pathway may be relevant for the biosynthesis of PUFA in cells lacking delta 6-desaturase activity.

Chromatography, Gas↗

PubMed1996

Efficacy of in vitro treatment of chronic myelogenous leukemia cell line, K562 cells, using 4-hydroperoxycyclophosphamide, alpha-interferon and gamma-interferon.

Alpha-interferon (alpha-IFN) and gamma-interferon (gamma-IFN) are highly effective biologic agents in the treatment of chronic myelogenous leukemia (CML). 4-hydroperoxycyclophosphamide (4-HC) is the most commonly used chemotherapeutic drug when purging bone marrow contaminated with malignant cells. To investigate the efficacy of alpha-IFN, gamma-IFN and 4-HC as purging agents in CML patients, K562 cells, a human CML cell line, were treated in vitro with these drugs singly or in combination. The cytotoxic effect was evaluated by MTT assay. Data were analyzed for synergism by the median effect principle of Chou and Talalay. Using Southern blot analysis, the effect of purging on the suppression of bcr gene rearrangement was also evaluated. Alpha-IFN, gamma-IFN and 4-HC all showed good concentration-dependent cytotoxic effect. Median cytotoxic doses of alpha-IFN gamma-IFN and 4-HC were 0.03 microM 0.20 microM and 1.97 microM respectively, and molar ratios of median doses of alpha-IFN to 4-HC, gamma-IFN to 4-HC and alpha-IFN to gamma-IFN were 1:80, 1:10 and 1:8, respectively. The combination treatment of alpha-IFN and 4-HC, and gamma-IFN and 4-HC showed significant synergistic cytotoxic activities, but combination of alpha-IFN and gamma-IFN was antagonistic. Status of bcr gene rearrangements in K562 cells was not changed after the treatments. Our results appear to provide an efficient method for removing CML cells from the bone marrow of CML patients.

Antineoplastic Agents↗

PubMed1990

A rapid redistribution of the transferrin receptor to the cell surface of HL-60 cells and K562 cells upon treatment with dimethyl sulfoxide due to slowing of endocytosis.

Treatment of two human leukemia cell lines with 1.25% dimethyl sulfoxide at 37 degrees C results in a rapid increase in the number of transferrin receptors on the cell surface detected by fluorescein-labeled anti-transferrin receptor antibodies. Both HL-60 cells, a human myeloid cell line, and K562 cells, a human erythroid-myeloid cell line, showed a 25-65% increase in cell surface transferrin binding in parallel experiments. Scatchard plot analysis of the data indicates that the number of receptors increases while the affinity of transferrin for the receptor remains the same. This rapid increase in the number of receptors at the cell surface appears to be due to a slowing of endocytosis rather than an increase in externalization of the receptor.

Cell Line↗

PubMed1996

Reduction of extracellular dehydroascorbic acid by K562 cells.

K562 erythroleukaemic cells produced ascorbate when incubated with dehydroascorbic acid. The reduction depended on the number of cells and on the concentration of dehydroascorbic acid. The observed rate consists of a high affinity (apparent Km 7 mu M, Vmax 3 center dot 25 pmol min-1 (10(6) cells)-1 and a low affinity component, which was non-saturable up to 1 mM of DHA (rate increase of 0 center dot 1 pmol min-1 (10(6) cells)-1 (1 mu M of DHA-1). The rate was dependent on temperature and was stimulated by glucose and inhibited by phloretin, N-ethylmaleimide, parachloro-mercuribenzoate and the noyltrifluoroacetone. Although uptake of DHA proceeded at a higher rate than its extracellular reduction, the generation of extracellular ascorbate from DHA cannot be accounted for by intracellular reduction and the release of ascorbate, since the latter was not linear with time and had an initial rate of approximately 3 pmol min-1 (10(6) cells-1). At a concentration of DHA of 100 mu M this is 25 per cent of the observed reduction.

Ascorbic Acid↗

PubMed2002

[Effects of anti-ABL tyrosine kinase intrabody on the growth of K562 cells in nude mice].

OBJECTIVE: To study the effects of anti-ABL tyrosine kinase intrabody on the growth of human chronic myelogenous leukemia (CML) cells in nude mice. METHODS: A recombinant retroviral vector MSCV-ibE-IRES-eGFP was constructed to express intracellular single-chain antibody (intrabody) against ABL tyrosine kinase domain in CML cells. K562 cells were transduced with the retrovirus, eGFP+ cells were then selected by fluorescence-activated cell sorting (FACS). The intrabody mRNA expression was determined by reverse transcription (RT)-polymerase chain reaction (PCR). BCR/ABL and c-ABL protein tyrosine kinase (PTK) activity in the cells was examined. Transduced cells and control group K562 cells were transplanted into nude mice respectively and the tumor sizes were dynamically observed. RESULTS: K562-ibE cell was obtained. Expression of the BCR/ABL and c-ABL protein tyrosine kinase activity of harvested K562-ibE cells were markedly inhibited. At 14, 21 and 28 days after cell injection, the tumor volumes of experimental mice were obviously smaller than that of control mice, about one half of the control groups (P < 0.05). CONCLUSION: The growth of K562-ibE cells was significantly inhibited in vivo. It is possible that inhibition of the BCR/ABL protein tyrosine kinase activity by the intrabody blocked BCR/ABL signal transduction pathway, promoted apoptosis and reduced tumorigenicity of K562 cells in vivo.

Animals↗

PubMed1992

Studies on the susceptibility to NK-mediated lysis and the simultaneous expression of various surface molecules in anthracyclin-treated K562 cells and in four K562 cell clones.

Target molecules for NK cells are unknown. Numerous studies have proposed putative target molecules, but have examined their role in the modulation of sensitivity to NK-mediated lysis one independently of each other. We examined the simultaneous expression of various surface molecules and the susceptibility of K562 cells to NK attack. We have previously shown that adriamycin (40 nM) and aclacinomycin (15 nM) can induce, in vitro, an increase of glycophorin A (GPA) on K562 cells, a modulation of transferrin receptor (TfR) and CD15 antigen expression and a significant resistance of cells to NK-mediated lysis. In the present work, Fc gamma receptor II (CD32) expression at the K562 cell membrane was clearly decreased after aclacinomycin-treatment but was unaltered by adriamycin-treatment. Four K562 cell clones were studied. Two clones (F and G) expressed a higher level of CD32 at the membrane (62% and 70% of erythrocyte antibody (EA) rosettes respectively) and two clones (9 and 19) expressed lower a level (18% and 7% EA rosettes respectively) than the original population (43%). The sensitivity to lysis by NK cells was increased in clones F, G and 9 but decreased in clone 19 (without alteration in the binding capacity). Relationships between the sensitivity to NK attack and the levels of simultaneous expression of CD32, TfR, CD15, glycophorin A (GPA) and MHC class I monomorphic antigens were studied. In addition, the presence at the membrane of some cellular adhesion molecules (CD54, CD58, CD29, CD18, CD56) was examined in anthracyclin-treated cells and in the four clones. The difference in the sensitivity of target cells to NK attack is not strictly related to variation of one or other of these molecules. Our previous and present data suggest that the resistance of K562 cells to NK cells may correlate with the level of erythroid maturation at the cell membrane, involving simultaneous variations in expression of several molecules such as a decrease of TfR, CD15 and CD32 and an increase of GPA.

Aclarubicin↗

PubMed1991

Development of a co-culture system with induced HepG2 cells and K562 cells for examining drug metabolism in vitro. Studies with cyclophosphamide, ondansetron and cisplatin.

We have established a cell co-culture system for assessing potential cytotoxic effects of drugs and their metabolites in vitro. Human hepatoma cells (HepG2) were cultured for 7 days in modified Earle's medium in order to induce their drug metabolising (primarily mixed function oxidase) enzymes. K562 human erythroleukemic cells in Transwells, were used as indicator cells for the cytotoxic effects of cyclophosphamide (CYP) and Ondansetron (OND) and/or their metabolites, produced by induced HepG2 cells in the co-cultures. CYP was found to be approximately 1000 times more toxic to K562 cells when cultured in the presence of induced HepG2 cells. OND, a selective 5-HT3 receptor antagonist which is used as an anti-emetic during chemotherapy, was not found to be cytotoxic in the co-cultures at concentrations as high as 100 microM. Since OND has been particularly useful in relieving vomiting induced by cisplatin (cisPt) chemotherapy, we also examined the effect of cisPt on K562 cells in the presence and absence of OND, and found no evidence that OND significantly enhances the cytotoxic effect of cisPt on these cells alone or in co-cultures with induced HepG2 cells. The induced HepG2 co-culture system uses cells of human origin and clearly has considerable potential for examining the effects of drugs and their metabolites on indicator cells derived from a tissue of choice. This system may be particularly useful in the assessment of metabolism and toxicity of new drugs intended for human use.

Antiemetics↗

PubMed2005

[Differentiation of K562 cells induced by antisense oligonucleotide targeting survivin].

OBJECTIVE: Gene therapy of leukemia is a new and effective method. It is known to all that the pathogenesis and development of leukemia are related to a variety of genes. Survivin is a member of inhibitors of apoptotic proteins (IAP). Its cDNA was cloned from target cell protease receptor-1 (EPR-1). It is expressed in common tumors, but there is no expression in normal and mature tissues. High expression of survivin was detected in leukemic cells. The present study was conducted to examine the role of survivin in the differentiation of leukemic cells by using antisense-oligonucleotides. METHODS: Human leukemic cell K562 was used as the model for the study. K562 cells were divided into 4 groups randomly: antisense oligonucleuotide (ASON) group, nonsense oligonucleotide (NSON) group, lipofectin group and control group. There were 5 samples in each group, and the experiment was repeated for three times. ASON was designed with the reference to targeting survivin mRNA. K562 cells were cultured in RPMI1640 contained fetal cattle serum at a concentration of about 10 percent. Cell transfection was induced by lipofectin. Forty-eight hours after thansfection, the morphology and ultrastructure were observed. Twenty-four hours and 48 hours after thansfection, the function of K562 cells was detected by benzidine staining, POX staining and NBT staining, respectively. The mean fluorescence intensity of CD33 was determined by flow cytometry. The method of immunohistochemistry was used to examine the protein level of survivin. RESULTS: After thansfection with ASON, the size of K562 cells was reduced, but the cytoplasm was increased. The metarubricyte, segment granulocyte, apoptotic cells could be found. Morphologically and ultrastructurally, erythroid and myelocytic differentiation was observed. The positive level of benzidine staining in ASON group (11.90 +/- 2.30 at 24 h and 18.20 +/- 2.93 at 48 h) was higher than that of NSON group, lipofectin group and control group, respectively. The positive level of POX staining in ASON group (17.40 +/- 3.54 at 24 h and 29.40 +/- 3.70 at 48 h) was also higher than that of any other groups. The positive level of NBT staining in ASON group (7.50 +/- 2.26 at 24 h and 12.10 +/- 2.63 at 48 h) was significantly higher than that of NSON group, lipofectin group and control group, respectively (P < 0.01). In ASON group, the mean fluorescence intensity of CD33 (21.43 +/- 1.61 at 24 h and 14.86 +/- 1.20 at 48 h) was significantly lower than that of any other groups (P < 0.01). After thansfection for 24 h, the protein level of survivin in ASON group was decreased significantly compared to that of control group. There was no difference in survivin protein level amongst ASON group, NSON group and lipofectin group at 24 h (P > 0.05). Forty-eight hours after thansfection, the protein level of survivin was decreased significantly. CONCLUSIONS: ASON targeting survivin can induce K562 to erythroid and myelocytic differentiation. Survivin is related to differentiation of K562 cells, and it can be a target of gene therapy for leukemia.

Antigens, CD↗