[Quantitative microarray-based DNA methylation analysis of E-cadherin gene promoter in acute leukemia].

OBJECTIVE: To quantitatively detect the methylation of E-cadherin gene 5'-CpG islands in acute leukemia by microarray-based DNA analysis and to briefly discuss the role of microarry for detection of methylation in tumors. METHODS: Bisulfite-modified DNA was used as a template for PCR amplification, resulting in conversion of unmethylated cytosine, but not methylated cytosine, into thymine within CpG islands of interest. Five sets of oligonucleotide probes were designed to fabricate a DNA microarray to detect the methylation changes of E-cadherin gene CpG islands in acute leukemia. By drawing a standard curve to assess the levels of changes in methylation detected in the examined samples. RESULTS: Microarray assay was successfully used to quantitatively detect methylation changes of E-cadherin gene in 5 acute leukemia samples. Varying degree of methylation was detected in five regions and the hypermethylation region was the same. The result was validated by gene sequencing. CONCLUSION: Microarray assay may be applied as an useful tool for mapping methylation changes in multiple CpG loci and for leukemia research. It is more time-saving and labor-saving than gene sequencing and can be used to quantitatively detect changes in methylation with high throughput.

[Optimization of Promoter and Support for Co-based/zeolites Catalysts in Catalytic Reduction of NOx by CH4].

Catalytic behavior of Co-based/zeolites catalysts was investigated in NOx reduction by CH4. Optimization of promoter and support was investigated by catalytic tests, and the relationship between catalytic activity and catalyst structure was illustrated by catalyst characterization. Co-Fe/SAPO-34 exhibited the highest activity among various Co-base/zeolites catalysts. The maximum conversion of NOx with 52.7% was obtained on Co-Fe/SAPO-34 at 450℃. The inhibition of activity of Fe/zeolites became severe in the presence of SO2, CO2, and H2O. CO2 exerted virtually no effect on the SCR activity of Co-Fe/zeolites. The inhibition of NOx conversion by H2O was reversible for Co-Fe/zeolites catalysts. Cobalt species were mainly present in CoO and Co(OH)2 states in Co-Fe/SAPO-34. Co3O4and Co(OH)2 were the main cobalt species of Co-Fe/ZSM-5, while CoO, CoAl2O4 and Co3O4 might be present in Co-Fe/Beta. The ratio of Fe2+/Fe3+ in the surface layer of Co-Fe/zeolites decreased in the order of Co-Fe/ZSM-5(3.98) > Co-Fe/SAPO-34(0.52) > Co-Fe/Beta(0.43). The active states of cobalt species and suitable ratio of Fe2+/Fe3+ were important for the activity of Co-Fe/zeolites in CH4-SCR. CH4-SCR over Co-Fe/zeolite catalysts started with the adsorption of NO and CH4 on Brønsted acid sites of the zeolite to produce NO+and carbon-containing species(-C=O and -COO) in the presence of oxygen, respectively. Subsequently, the important intermediates of nitrate species were generated from NO+ at the active sites. Finally, nitrate species reacted with carbon-containing species to form N2 and CO2.

Effects of magnetic nanoparticle of Fe3O4 on apoptosis induced by Gambogic acid in U937 leukemia cells.

This study was aimed to explore the potential therapy of Gambogic acid (GA) combined with magnetic nanoparticle of Fe3O4 (Fe3O4-MNP) on leukemia. The proliferation of U937 cells and the cytotoxicity were evaluated by MTT assay. Cell apoptosis was observed and analyzed by microscopy and flow cytometry respectively. The expressions of gene and protein were detected by quantitative real-time polymerase chain reaction and Western blot respectively. The results showed that GA enhanced the cytotoxicity for U937 cells in dose- and time-dependent manners. The Fe3O4-MNP itself had not cytotoxicity, but could enhance the inhibitory effect of GA on proliferation of U937 cells. The apoptotic rate of U937 cells induced by combination of GA with Fe3O4-MNP was higher than that by GA alone. The typical apoptotic features of cells treated with GA and Fe3O4-MNP were observed. The expression levels of caspase-3 and bax after co-treatment of GA and Fe3O4-MNP were higher than that exposed to GA or Fe3O4-MNP alone, but the expressions of bcl-2, NF-kappaB and survivin were down-regulated. It is concluded that Fe3O4-MNP can promote GA-induced apoptosis in U937 cells, and the combination of GA with Fe3O4-MNP may be a safer and less toxic new therapy for leukemia.

Reversal of multidrug resistance by magnetic Fe3O4 nanoparticle copolymerizating daunorubicin and MDR1 shRNA expression vector in leukemia cells.

In many instances, multidrug resistance (MDR) is mediated by increasing the expression at the cell surface of the MDR1 gene product, P-glycoprotein (P-gp), a 170-kD energy-dependent efflux pump. The aim of this study was to investigate the potential benefit of combination therapy with magnetic Fe(3)O(4) nanoparticle [MNP (Fe(3)O(4))] and MDR1 shRNA expression vector in K562/A02 cells. For stable reversal of "classical" MDR by short hairpin RNA (shRNA) aiming directly at the target sequence (3491-3509, 1539-1557, and 3103-3121 nucleotide) of MDR1 mRNA. PGC silencer-U6-neo-GFP-shRNA/MDR1 called PGY1-1, PGY1-2, and PGY1-3 were constructed and transfected into K562/A02 cells by lipofectamine 2000. After transfected and incubated with or without MNP (Fe(3)O(4)) for 48 hours, the transcription of MDR1 mRNA and the expression of P-gp were detected by quantitative real-time PCR and Western-blot assay respectively. Meanwhile intracellular concentration of DNR in K562/A02 cells was detected by flow cytometry (FCM). PGC silencer-U6-neo-GFP-shRNA/MDR1 was successfully constructed, which was confirmed by sequencing and PGY1-2 had the greatest MDR1 gene inhibitory ratio. Analysis of the reversal ratio of MDR, the concentration of daunorubicin (DNR) and the transcription of MDR1 gene and expression of P-gp in K562/A02 showed that combination of DNR with either MNP (Fe(3)O(4)) or PGY1-2 exerted a potent cytotoxic effect on K562/A02 cells, while combination of MNP (Fe(3)O(4)) and PGY1-2 could synergistically reverse multidrug resistance. Thus our in vitro data strongly suggested that a combination of MNP (Fe(3)O(4)) and shRNA expression vector might be a more sufficient and less toxic anti-MDR method on leukemia.

Daunorubicin-loaded magnetic nanoparticles of Fe3O4 overcome multidrug resistance and induce apoptosis of K562-n/VCR cells in vivo.

Multidrug resistance (MDR) is a major obstacle to cancer chemotherapy. We evaluated the effect of daunorubicin (DNR)-loaded magnetic nanoparticles of Fe3O4 (MNPs-Fe3O4) on K562-n/VCR cells in vivo. K562-n and its MDR counterpart K562-n/VCR cell were inoculated into nude mice subcutaneously. The mice were randomly divided into four groups: group A received normal saline, group B received DNR, group C received MNPs-Fe3O4, and group D received DNR-loaded MNPs-Fe3O4. For K562-n/VCR tumor, the weight was markedly lower in group D than that in groups A, B, and C. The transcriptions of Mdr-1 and Bcl-2 gene were significantly lower in group D than those in groups A, B, and C. The expression of Bcl-2 was lower in group D than those in groups A, B, and C, but there was no difference in the expression of P-glycoprotein. The transcriptions and expressions of Bax and caspase-3 in group D were increased significantly when compared with groups A, B, and C. In conclusion, DNR-loaded MNPs-Fe3O4 can overcome MDR in vivo.

MDR reversal activity of bromotetrandrine in vitro and in vivo.

The present study was aimed to evaluate the MDR reversal activity of bromotetrandrine (BrTet) in vitro and in vivo. The inhibitory effects of adriamycin (ADM) used alone or in combination with BrTet or Tet on the proliferation of K562 and K562/A02 cells were evaluated by MTT assay. The ADM accumulation and the protein levels of P-glycoprotein (P-gp) were detected by flow cytometry. The mRNA levels of P-gp were determined by RT-PCR. The in vivo effect of BrTet and Tet was investigated by using nude mice grafted with sensitive human leukemia cell line K562 and MDR cell line K562/A02. The results showed that BrTet at 0.25, 0.5 and 1 micromol/L reversed the resistance to ADM in MDR K562/A02 cells in a dose-dependent manner. Flow cytometry suggested that BrTet significantly increased the intracellular accumulation of ADM in K562/A02 cells in a dose-dependent manner. BrTet also inhibited the overexpression of P-gp in K562/A02 cells, and down-regulated mdr1 expression. In nude mice bearing K562 xenografts on the left flank and K562/A02 xenografts on the right flank, intraperitoneal injection of 10 mg/kg BrTet significantly enhanced the antitumor activity of ADM against K562/A02 xenografts with inhibitory rates of 26.1%, while ADM alone inhibited the growth of K562/A02 xenografts only by 5.8%. No enhancement effect by BrTet was seen in K562 xenografts. It is concluded that BrTet shows significant MDR reversal activity in vitro and in vivo. Its activity may be related to the inhibition of P-gp overexpression and the increase intracellular accumulation of anticancer drugs. BrTet may be a promising-MDR modulator for eventual assessment in the clinic.

Synergistic effect of the combination of nanoparticulate Fe3O4 and Au with daunomycin on K562/A02 cells.

In this study, we have explored the possibility of the combination of the high reactivity of nano Fe3O4 or Au nanoparticles and daunomycin, one of the most important antitumor drugs in the treatment of acute leukemia clinically, to inhibit MDR of K562/A02 cells. Initially, to determine whether the magnetic nanoparticle Fe3O4 and Au can facilitate the anticancer drug to reverse the resistance of cancer cells, we have explored the cytotoxic effect of daunomycin (DNR) with and without the magnetic nano-Fe3O4 or nano-Au on K562 and K562/A02 cells by MTT assay. Besides, the intracellular DNR concentration and apoptosis of the K562/A02 cells was further investigated by flow cytometry and confocal fluorescence microscopic studies. The MDR1 gene expression of the K562/A02 cells was also studied by RT-PCR method. Our results indicate that 5.0 x 10(-7) M nano-Fe3O4 or 2.0 x 10(-8) M nano-Au is biocompatible and can apparently raise the intracellular DNR accumulation of the K562/A02 cells and increase the apoptosis of tumor cells. Moreover, our observations illustrate that although these two kinds of nanoparticles themselves could not lower the MDRI gene expression of the K562/A02 cells, yet they could degrade the MDR1 gene level when combining with anticancer drug DNR. This raises the possibility to combine the nano-Fe3O4 or nano-Au with DNR to reverse the drug resistance of K562/A02 cells, which could offer a new strategy for the promising efficient chemotherapy of the leukemia patients.

[Effect of tetrandrine in combination with droloxifen on the expression of NF-kappaB protein in K562 and K562/A02 cell lines].

OBJECTIVE: To study the effect of tetrandrine (Tet) in combination with droloxifen (DRL) on the expression of nuclear factor kappa B (NF-kappaB) in K562 and K562/A02 cell lines and its reversal mechanism. METHODS: The activation of NF-kappaB in K562 and K562/A02 cell lines and the effect of Tet or DRL alone or in combination on NF-kappaB protein expression were determined with immunocytochemistry and Western blotting respectively. RESULTS: (1) K562/A02 cells displayed higher level of NF-kappaB protein expression than K562 cells. (2) The application of Tet or DRL alone or in combination had no effect on NF-kappaB expression in K562 cells at 6 h and 12 h (P > 0.05). (3) Tet and DRL alone or in combination could significantly down-regulate NF-kappaB protein expression in nuclei of K562/A02 cells. The effect was more significant in combination than either alone. This effect was more significant at 12 h than at 6 h. CONCLUSIONS: (1) Activation of NF-kappaB may be involved in the mechanism of MDR of K562/A02 cell line. (2)Inhibition of NF-kappaB activation may be involved in the reversal of multidrug resistance in K562/A02 cells by Tet and DRL.

Detection of complex karyotype in a myelodysplastic syndrome cell line (MUTZ-1) by metaphase fluorescence in situ hybridization.

This study was aimed to investigate the cytogenetic changes of MDS cell line (MUTZ-1) with chromosome 5q deletion. R-banding analysis was used to identify chromosome aberrations in MDS cell line and Vysis Spectra Vysion M-FISH was used to further characterize chromosomal complex karyotype. The results indicated that M-FISH exhibited obvious chromosomal aberrations with high frequency including translocation, insertion, breakage and rearrangement, deletion and increasement of chromosome number, the complex karyotype of MUTZ-1 was shown as 50, xx, der (1) t (1;2), ins (1;14), +der (2) t(2;19), der (3) t (3;5), der (3) (3::5::22), 5q-, der (6) t (3;6), der (7) (18::7::17), +8, +der (9) t (1;9), der (10) t (1;10), +11, +12, der (?13) (10::13::5::8), der (14) t (8;14), der (14) t (14, 15), der (15) t (15;21) x 2, +17, +18, -21, -22. It is concluded that M-FISH analysis revealed obvious changes in complex karyotype of MDS cell line MUTZ-1, and the M-FISH technique can increase accuracy of detection for chromosomal complex karyotype, and help diagnosis and prognostic evaluation of MDS.

[Effects of sensitized donor lymphocyte infusion on the chimerism and graft-versus-host disease after nonmyeloablative allogeneic stem cell transplantation].

To explore whether the complete donor chimerism could be achieved and graft-versus-host disease could be alleviated by donor lymphocyte infusion which was sensitized by the skin of the recipient, female C57BL/6 mice (H-2(b), B6) as recipients received total body irradiation (TBI) of 5.5 Gy ((60)Co gamma-ray) on day 0 followed by allogeneic hematopoietic stem cell transplantation (allo-HSCT). The allo-grafts consisted of 2 x 10(7) peripheral hematopoietic stem cells from mobilized male BALB/c (H-2(d)) donor mice with the granulocyte colony-stimulating factor (G-CSF). Day 2 after allo-HSCT, the recipient mice were given 200 mg/kg cyclophosphamide intraperitoneally. Afterwards these recipient mice were infused 2 x 10(6) sensitized or unsensitized-donor lymphocytes at the 28 days after transplantation. The results showed that the mice receiving sensitized-donor lymphocyte infusion did not suffer from GVHD and the phenotypic character of the recipient mice (black color) converted to that of the donor mice (white color), and to become full-donor chimerism. It was found that the ratio of CD4(+)/CD8(+) T lymphocytes of them decreased at the earlier period and increased after half month, but which were also lower than that of the normal value. While various grades of acute GVHD was observed in that of the control group and the mixed-chimeras were maintained, though it increased a little, and the ratio of CD4(+)/CD8(+) T lymphocytes increased at first, then decreased to the normal level half month later. It is concluded that sensitized DLI converted mixed to complete donor chimerism without GVHD, and the rate of CD4(+)/CD8(+) has close relation to the incidence of GVHD.