Methylenetetrahydrofolate reductase gene polymorphisms association with the risk of diffuse large B cell lymphoma: a meta-analysis.

To date, case-control studies on the association between methylenetetrahydrofolate reductase (MTHFR) and diffuse large B cell lymphoma (DLBCL) have provided either controversial or inconclusive results. To clarify the effect of MTHFR on the risk of diffuse large B cell lymphoma, a meta-analysis of all case-control observational studies was performed. The fixed effects and random effects model showed that the C677T polymorphism was associated with a risk of DLBCL among East Asian populations, and A1298C polymorphism was not associated with a risk of DLBCL among Caucasian and East Asian populations. Our pooled data suggest evidence for a major role of MTHFR C677T polymorphism in the carcinogenesis of DLBCL among East Asian populations.

Methylenetetrahydrofolate reductase gene polymorphisms association with the risk of follicular lymphoma: a meta-analysis.

To date, case-control studies on the association between methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms and follicular lymphoma have provided controversial results. To clarify the effect of MTHFR polymorphisms on the risk of follicular lymphoma, a meta-analysis of all case-control studies was performed. The fixed effects and random effects model showed that the C677T polymorphism was associated with a risk of follicular lymphoma among Caucasian populations, and A1298C polymorphism was associated with a risk of follicular lymphoma among Asian populations. Our pooled data suggest evidence for a major role of MTHFR polymorphisms in the carcinogenesis of follicular lymphoma.

Covalent Organic Framework-Based Nanomotor for Multimodal Cancer Photo-Theranostics.

Developing efficient integrated diagnosis and treatment agents based on fuel-free self-movement nanomotors remains challenging in antitumor therapy. In this study, a covalent organic framework (COF)-based biomimetic nanomotor composed of polypyrrole (PPy) core, porphyrin-COF shell, and HCT116 cancer cell membrane coating is reported. Under near-infrared (NIR) light irradiation, the obtained mPPy@COF-Por can overcome Brownian motion and achieves directional motion through self-thermophoretic force generated from the PPy core. The HCT116 cancer cell membrane coating enables the nanomotor to selectively recognize the source cell lines and reduces the bio-adhesion of mPPy@COF-Por in a biological medium, endowing with this NIR light-powered nanomotor good mobility. More importantly, such multifunctional integration allows the COF-based nanomotor to be a powerful nanoagent for cancer treatment, and the high infrared thermal imaging/photoacoustic imaging/fluorescence trimodal imaging-guided combined photothermal/photodynamic therapeutic effect on HCT116 tumor cell is successfully achieved. The results offer considerable promise for the development of COF nanomotors with integrated imaging/therapy modalities in biomedical applications.

[Analysis of risk factors for relapse of 82 patients with hematologic malignancies after allogeneic hematopoietic stem cell transplantation].

OBJECTIVE: To explore the risk factors for relapse after allogeneic hematopoietic stem cell transplantation (allo-HSCT) and the measures of prophylaxis and treatment. METHODS: We summarized the clinical data of 82 patients with hematologic malignancies who were treated in our hospital from August 2003 to December 2008. Factors including age, sex, ABO blood group disparity of donor and recipient as well as the type of donor, status of disease, HLA-match, conditioning regimen, whether or not having developed acute GVHD and chronic GVHD, infusion number of CD34(+) cells, relationship between CMV infection and relapse post-transplantation were considered and analyzed. RESULTS: Single factor analysis indicated that there were five independent risk factors related with the disease relapse (P < 0.05), including status of disease, time of diagnosis to transplantation, acute graft versus host disease (aGVHD), conditioning regimen, and chronic graft versus host disease (cGVHD). Simultaneously, the type of donor was a substantial factor (P < 0.01), determined by multi-factor Cox regression analysis. Cox regression analysis determined that disease status (OR = 2.58, 95%CI 1.26 - 5.01, P = 0.01), time from diagnosis to treatment (OR = 1.98, 95%CI 1.11 - 3.63, P = 0.025) and cGVHD (OR = 3.74, 95%CI 1.96 - 7.97, P < 0.001) were major factors for relapse of the patients who had undergone transplantation. CONCLUSIONS: Relapse remains the primary cause of failure after allo-HSCT. Status of disease, time from diagnosis to treatment and not cGVHD are the major risk factors. Effective prevention and treatment of relapse after engraftment can improve the efficacy of HSCT.

[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.

[Effect of gambogic acid on proliferation of SKM-1 cells and its mechanism].

The aim of this study was to explore the effect of gambogic acid (GA) on MDS SKM-1 cell proliferation, apoptosis and their possible mechanism. Cell proliferation was determined by MTT method. The apoptosis percentage and cell cycle regulation of SKM-1 cells were analyzed by flow cytometry. Morphological features were observed by light microscopy. The mRNA expression of bcl-2 and bax were detected by RT-PCR. The results showed that GA could inhibit the proliferation of SKM-1 cells in a dose- and time-dependent manner (IC50 was 0.37 µg/ml at 48 h), increase the apoptotic percentage of SKM-1 cells, and arrest cell cycle at the G0/G1. The expression of bax mRNA was up-regulated while that of bcl-2 mRNA was down-regulated in SKM-1 cells treated with GA for 48 h. It is concluded that GA can induce apoptosis, which may be related to its effect of arresting cells at phase of G0/G1 and down-regulating bcl-2/bax ratio.

Endothelial progenitor cells in primary aldosteronism: a biomarker of severity for aldosterone vasculopathy and prognosis.

CONTEXT: Primary aldosteronism (PA) is associated with a higher incidence of cardiovascular events, probably through mineralocorticoid receptor (MR)-dependent endothelial cell dysfunction, in comparison with essential hypertension (EH). OBJECTIVE: Our objective was to investigate the number and function of endothelial progenitor cells (EPC) in PA and the relationship with arterial stiffness and disease progression. DESIGN AND SETTING: We conducted a prospective study of the change of EPC number and outcome of PA patients after treatment at a tertiary medical center. PRIMARY OUTCOMES: Changes in arterial stiffness and EPC number after treatment and the curability of hypertension were assessed. PATIENTS: A total of 113 PA patients (87 patients diagnosed with aldosterone-producing adenoma, 26 with idiopathic hyperaldosteronism) and 55 patients with EH participated. RESULTS: PA patients had higher arterial stiffness than EH patients (P = 0.006), with a lower numbers of circulating EPC and endothelial colony-forming units (P < 0.05). The differences were ameliorated at 6 months after unilateral adrenalectomy or treatment with spironolactone. Expression of MR was identified in the EPC. The number of circulating EPC was inversely correlated with the plasma aldosterone concentration (P = 0.021), arterial stiffness (P = 0.029) and serum high-sensitivity C-reactive protein (P = 0.03). High-dose aldosterone (10(-5) and 10(-6) m) attenuated EPC proliferation and angiogenesis in vitro. Among the 45 patients who underwent unilateral adrenalectomy, 32 (71%) were cured of hypertension. The preoperative number of EPC [log(EPC number percent) >-3.6] predicted the curability of hypertension after adrenalectomy (P = 0.003). CONCLUSIONS: The relative deficiency of EPC in PA patients may contribute to aldosterone vasculopathy, which can be reversed by adrenalectomy and spironolactone. High aldosterone levels attenuated EPC proliferation and angiogenesis. Circulating EPC number may be a valuable biomarker to identify PA patients with a high incidence of arterial stiffness and to predict postoperative residual hypertension of aldosterone-producing adenoma.

[Effect of hypoxia inducible factor1-α inhibitor on reversal of multidrug resistance of K562/A02 cell line].

OBJECTIVE: To study the reversal effect of the hypoxia inducible factor (HIF)-1α inhibitor, YC-1, on multidrug resistance of K562/A02 cells and its mechanism. METHODS: Pre- and post- incubation with adriamycin (ADM) alone or in combination with YC-1 for 48 h, the proliferation capacity of K562/A02 and K562 cells were evaluated by MTT assay. The apoptosis rate of K562/A02 cells after treated with 0, 5, 10 and 20 µmol/L YC-1 alone or in combination with 1 mg/L ADM and intracellular ADM concentration were analyzed by flow cytometry (FCM). The mRNA levels of HIF-1α and mdr1 genes were determined by semi-quantitative RT-PCR. The protein levels of HIF-1α and P-glycoprotein (P-gp) were detected by Western blot. RESULTS: The IC(50) of ADM for K562 and K562/A02 cells were (1.56 ± 0.07) mg/L and (42.98 ± 3.15) mg/L respectively. The resistance of K562/A02 cells to ADM was 27.55- fold higher of that of K562 cells. After treatment with YC-1 (5 µmol/L, 10 µmol/L, 20 µmol/L) for 48h, the resistances of K562/A02 cells to ADM were 24.63-, 16.38- and 10.71- fold increase respectively. After treatment of K562/A02 cell with YC-1 (0 µmol/L, 5 µmol/L, 10 µmol/L, 20 µmol/L) alone or in combination with 1 mg/L ADM for 48 h, the apoptotic rates were (1.9 ± 0.9)%, (4.9 ± 0.9)%, (5.8 ± 1.1)%, and (9.3 ± 1.4)% and (2.3 ± 0.7)%, (8.2 ± 1.2)%, (19.0 ± 1.7)%, and (34.5 ± 2.4)% respectively. The intracellular flucorescence intensity of ADM were 232 ± 33, 1300 ± 219, 1961 ± 240 and 3342 ± 269 in the combined treatment group. With the increase in YC-1 concentration, the levels of mdr1 mRNA reduced, while that of HIF-1α mRNA had no obvious change. Furthermore, the expressions of HIF-1α and P-gp were also decreased in K562/A02 cells. CONCLUSION: YC-1, as a HIF-1 inhibitor, can reverse multidrug resistance of K562/A02 cells through down-regulating HIF-1α and P-gp.

[Effects of hypoxia-inducible factor inhibitor on expression of HIF-1alpha and VEGF and induction of apoptosis in leukemic cell lines].

This study was purposed to investigate the effect of a hypoxia-inducible factor inhibitor (YC-1) on expression of hypoxia-inducible factor 1alpha (HIF-1alpha) and vascular endothelial growth factor (VEGF) as well as induction of apoptosis in leukemic cell lines. RT-PCR was used to determine the levels of HIF-1alpha mRNA and VEGF mRNA in K562, U937 and Jurkat cells. After treatment of U937 cell with 4 micromol/L YC-1, cell apoptosis was assayed by DAPI staining under fluorescent microscope and flow cytometry with Annexin V-FITC/PI staining; the expression levels of HIF-1alpha mRNA and VEGF mRNA were measured with RT-PCR; the expression levels of HIF-1alpha, VEGF, BAX, BCL-2 and caspase-3 proteins were measured by Western blot. The results showed that HIF-1alpha mRNA and VEGF mRNA were expressed in all three leukemia cell lines. After treatment of U937 cell with 4 micromol/L YC-1 for 0, 8, 16 and 24 hours, the changes of morphologic features of U937 cells could be observed under fluorescent microscope and the apoptotic rates significantly increased in time-dependent manner, they were (4.87 +/- 0.70)%, (27.27 +/- 2.00)%, (51.53 +/- 2.81) and (60.5 +/- 3.20)% respectively, the expression levels of VEGF mRNA reduced, while the expression levels of HIF-1alpha mRNA had no obviously changes.Furthermore, the expression of HIF-1alpha, VEGF and BCL-2 decreased, while the expression of BAX and caspase-3 increased, the ratio of BAX/BCL-2 increased in time-dependent manner (r = 0.973, p < 0.01). It is concluded that HIF-1alpha mRNA and VEGF mRNA are all expressed in in K562, U937 and Jurkat cells, YC-1 has significant effect on down-regulating the protein expression of HIF-1alpha and VEGF, and induces the apoptosis in U937. The mechanism of apoptosis in leukemic cells may involve in up-regulating BAX/BCL-2 ratio and expression of protein caspase-3.

[Effect of PDMP, a glucosylceramide synthase inhibitor, on reversion of daunorubicin resistance in human leukemia cell line K562/A02].

This study was purposed to investigate the reversal effect of glucosylceramide synthase (GCS) inhibitor D, L-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (PDMP) hydrochloride, on multidrug resistance in K562/A02 cells and its mechanism. The IC(50) (the half maximal inhibitory concentration) of PDMP was measured by MTT method. Cell apoptosis and intracellular daunorubicin (DNR) concentration were detected by flow cytometry. The expression of GCS and mdr1 genes were assayed by semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR) and Western blot. The results showed that the IC(50) of DNR in K562 and K562/A02 cells were 0.23 +/- 0.02 and 7.15 +/- 0.24 microg/ml respectively. When the concentration of PDMP was equal to or less than 20 micromol/L ( < / = 20 micromol/L), the obviously inhibitory effect on proliferation of K562 and K562/A02 cells was not observed, but both 20 micromol/L and 10 micromol/L PDMP could enhance the sensitivity of K562/A02 cells to DNR (p < 0.01) and the reversal multiples were 2.59 and 1.69 respectively. After treating with 20 micromol/L and 10 micromol/L PDMP for 48 hours, the concentration of DNR in K562/A02 cells increased (p < 0.05) and the apoptotic rate also was elevated (p < 0.01). The expressions of GCS and mdr1 genes were down-regulated at mRNA and protein levels after treating K562/A02 cells with 20 micromol/L PDMP for 48 hours. It is concluded that PDMP can enhance the sensitivity of K562/A02 cells to DNR by increasing cell apoptosis rate and accumulation concentration of DNR in cells, which may be related to down-regulated expressions of GCS and mdr1 genes.

[Reversal of multidrug-resistance in human leukemia cell line K562/A02 by tyrosine kinase inhibitors].

This study was aimed to investigate the reversal effect of tyrosine kinase inhibitors (TKI) Imatinib and Nilotinib on multidrug-resistant cell line K562/A02. The expression levels of mdr-1 mRNA and bcr-abl mRNA were assayed by RT-PCR. The protein levels of P-glycoprotein (P-gp) and P210 were detected by Western blot. The daunorubicin (DNR) accumulation in K562/A02 cells were analyzed by flow cytometry (FCM). The results showed that the 0.0625 micromol/L Imatinib or 5 nmol/L Nilotinib alone had no cytotoxic effect on the inhibition of K562/A02 cells. When K562/A02 cells were treated with Imatinib or Nilotinib alone for 48 hours, the expressions of mdr-1 mRNA, der/abl mRNA, P-gp and P210 protein were all down-regulated, furthermore the effect of Nilotinib was stronger than that of Imatinib. The detection of fluorescence intensity revealed that the DNR concentration in K562/A02 cells treated with Imatinib or Nilotinib alone for 48 hours were 7.85% and 12.02% of K562 cells respectively. It is concluded that the tyrosine kinase inhibitors show great effect reversing drug resistance of cells, moreover, the effect of Nilotinib is stronger than that of Imatinib.

[Construction and identification of Mdr-1-shRNA eukaryotic expression vector].

This study was purposed to construct and identify the short hairpin RNA (shRNA) eukaryotic expression vector for targeting gene mdr-1 which may play an important role in K562/A02. Short hairpin RNA (shRNA) aiming at the target sequence was to synthesized, the 3491-3509, 1539-1557and 3103-3121 nucleotide of mdr-1 mRNA were selected as targets. The selected nucleotides were cloned in the plasmid pGCSilencer-U6-neo-GFP respectively, and the resultant recombinant plasmids were named as pGY1-1, pGY1-2 and pGY1-3. The sequences of the recombinant plasmids were identified by DNA sequencing and PCR electrophoresis. The recombinant plasmids were transfected into the cell line K562/A02 by lipofection. After being transfected for 48 hours, the inhibition of mdr-1 mRNA was detected by real time-PCR, and P-gp expression was detected by Western blot. The results showed that the specific oligonucleotide was cloned into the vector successfully, and the expression of mdr-1 mRNA and P-gp in K562/A02 cells was reduced after transfecting the recombinant plasmid, as compared to the control group. It is concluded that the shRNA eukaryotic expression vector has been successfully established which can inhibit the expression of mdr-1 mRNA, setting up the basis to futher explore the effects of mdr-1 on cell line of K562/A02.

[Analysis on laboratory and clinical characteristics in 65 cases of myelodysplastic syndrome].

The aim of this study was to gain more insight into the understanding of myelodysplastic syndrome in the clinical and laboratory features. The clinical data of 65 patients with MDS were reviewed and analysed. According to FAB criteria, 65 patients were classified as follows: 27 patients with RA, 1 patient with RAS, 33 patients with RAEB, 3 patients with RAEB-T, and 1 patient with CMML. The median age of them was 66 years old (range 19-89 years), and 6 patients had a history of toxic exposure (secondary MDS). The bone marrow smears, bone marrow biopsy and cytogenetic examinations were performed in this study. The results showed that dysplasia was found in 64 patients examined with bone marrow smears (98.5%), among them trilineage dysplasia in 21 patients (32.3%), bilineage dysplasia in 33 patients (50.8%), only erythroid dysplasia in 8 cases (12.3%) and 2 patients (3.1%) only with myeloid dysplasia. The bone marrow biopsy was performed in 38 patients, abnormal localization of immature precursor (ALIP) occurred in 6 cases. 29 patients had abnormal karyotypes, accounting for 59.2% of the 49 patients subjected cytogenetic examination. The abnormal chromosome was the major cytogenetic abnormality, which occurred more often in secondary MDS and the patients with RAEB or RAEB-T. Among the 49 patients who had received cytogenetic examination, 15 patients transformed into AML with the incidence of 30.61%, but only 3 out of 20 patients in the group of normal chromosome transformed into AML (15%), while 12 out of 29 patients in the group of abnormal karyotypes transformed into AML (41.4%). The median time of following up was 35 months (range 2 - 106 months). The median survival time was 26.8 months and 8 months in the patients with normal karyotype and chromosome aberrations respectively. In conclusion, the incidence of MDS in our country is younger than that in Western countries, the rate of abnormal chromosome in high risk MDS is higher than that in low risk MDS. Meanwhile, those who have the change of chromosome are related to the transformation of MDS into AML and have shorter survival time than those MDS patients with normal karyotypes.

[Auto-hematopoietic stem cell transplantation for multiple myeloma accompanied with amyloidosis in four limbs].

The study was aimed to investigate the effective therapeutic method for patients with multiple myeloma accompanied with amyloidosis. A 58-year-old patient diagnosed as multiple myeloma accompanied with amyloidosis in four limbs was enrolled in this study. The various clinical and laboratorial examinations were performed, including bone marrow smear, immunologic test, radiography and so on. Patient received chemotherapeutic drugs and then autologous hematopoietic stem cell transplantation (auto-HSCT). The result showed that hematopoietic reconstitution was achieved at 23 days after auto-HSCT. Immunofixation electrophoresis was normal. There was only 0.6% plasma cells in the bone marrow. In conclusion, the auto-HSCT may be an effective treatment for multiple myeloma accompanied with amyloidosis in four limbs.

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.

[Effect of tetrandrine, toremifene and their combination on the reversion of multidrug resistance of K562/A02 cell line].

This study was aimed to investigate the reversible effect of tetrandrine, toremifene and their combination on multidrug resistance of K562/A02 cell line. The IC(50) (the concentration causing 50% inhibition of cell growth) of adriamycin (ADR) were assayed by MTT method, the expression of MDR1 mRNA was measured by RT-PCR, the concentration of p-glycoprotein (P-gp) and intracellular ADR were detected by flow cytometry. The results showed that the IC(50) of ADR on K562/A02 and K562 cells were 57.43 and 1.16 mg/L, respectively. The IC(50) of ADR on K562/A02 cells after treatment with tetrandrine, toremifene and both combination were 14.12, 20.74 and 9.14 mg/L respectively, but both drugs did not influence the IC(50) of ADR on K562 cells. Pretreating K562/A02 cells with toremifene (2.5 micromol/L), tetrandrine (1 micromol/L) or both for 72 hours partially restored the sensitivity of K562/A02 cells to ADR. Tetrandrine and toremifene (alone or combination) elevated the ADR concentration in K562/A02, down regulated the expressions of P-gp and MDR1 mRNA. It is concluded that multidrug resistance of K562/A02 cells can be partially reversed by tetrandrine or toremifene, the combination of both drugs shows a higher synergistic reversal effect.

[Nonmyeloablative peripheral blood stem cell transplantation for chronic myeloid leukemia in chronic and accelerated phases].

The aim of this study was to investigate the effect of nonmyeloablative peripheral blood stem cell transplantation in treatment of chronic myeloid leukemia in chronic phase (CML-CP) and accelerated phase (CML-AP). 24 patients with CML including 16 in CML-CP and 8 in CML-AP were treated with nonmyeloablative conditioning regimen for peripheral blood stem cell transplantation (PBHSCT). The conditioning regimen included fludarabine (30 mg/m(2)x6 d), busulphan [4 mg/(kg.d)x2 d] and CTX [350 mg/(m2.d)x2 d] combined with or without Ara-C. The donors were HLA-identical (n=20) and 5/6 antigen-matched (n=4). The dynamic observation of hematopoietic recovery in all patients was carried out. The results indicated that all the patients were successfully engrafted. The mean time for increase of the number of neutrophils to more than 0.5x10(9)/L and platelet more than 20x10(9)/L were 13 days and 11.5 days respectively. Out of 12 patients, 9 patients showed complete donor chimerism and 3 patients showed mixed chimerism at 30 days after transplantation. At 180 days after transplantation, 18 survival patients showed complete donor chimerism. 18 patients remained alive after a median follow-up length of 24 months (4-48 months). 2 cases died of severe acute GVHD and 1 case died of chronic GVHD, 2 cases died of interstitial pneumonia and 1 case died of relapsed. In conclusions, nonmyeloablative peripheral blood stem cell transplantation is an effective therapeutic method for CML patients in chronic phase and accelerated phase.

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.

[Enhancement of reversing drug resistance of K562/A02 cells to adriamycin by ultrasound-induced cavitation].

This study was aimed to investigate the effects of low frequency and power ultrasound combined with adriamycin on apoptosis of drug-resistant leukemia cell line K562/A02 in vitro, to find out the parameters of optimal exposure, and to explore the possible mechanism reversing drug-resistance of K562/A02 cells. The K562/A02 cells in logarithmic growth phase were used in experiments. The experiments were divided into 4 groups: group control, group adriamycin (A02) alone, group ultrasound (US) alone and group A02+US. The trypan blue dye exclusion test and MTT assay were used to determine the cell viability; Wright's staining was used to detect the apoptosis; the flow cytometry was used to analyze the drug concentration, and the scanning electron microscopy was used to observe the changes of cell surface. The results showed that the significant differences in cell viability, intracellular adriamycin concentration and changes of cell membrane were found between ultrasound-treated and untreated cells in the presence of various concentration of adriamycin. The exposure to ultrasound at 20 kHZ, 0.25 W/cm2 for 60 seconds could obviously decrease LC50 of adriamycin to K562/A02 cells, while the exposure to ultrasound at 20 kHZ, 0.05 W/cm2 for 60 seconds could kill K562/A02 cells at once. After being treated by low frequency ultrasound, the small holes with diameter about 1-2 microm in the cell surface appeared. The ultrasound increased the adriamycin concentration in the cells, accelerated the formation of apoptotic bodies, and promoted apoptosis of adriamycin-resistant cells. It is concluded that the ultrasound at optimal parameters enhances inhibitory effect of adriamycin on drug-resistant cell line, thereby reverses drug-resistance of drug-resistant cell line through sound-hole effect in tumor cells resulting from ultrasound induced cavitation.

[Influence of tetrandrine on SORCIN gene expression in K562/A02 cell line].

This study was aimed to explore the changes of soluble resistance-related calcium binding protein (sorcin) expression in reversion of multidrug resistance of K562/A02 leukemic cell line with different concentrations of tetrandrine (Tet), so as to provide a new theoretic evidence for clinical application of Tet. The inhibition of K562/A02 cell line by daunorubicin (DNR) was assayed by MTT method. The changes of SORCIN gene expression were assayed by RT-PCR. The changes of SORCIN protein expressed were assayed by Western blot. The results showed that Tet could enhance the cytotoxicity of DNR to K562/A02 cells (the IC(50) of DNR + Tet was 11.3+/-0.17 mg/L, 5.15+/-0.10 mg/L, 3.91+/-0.06 mg/L, and 2.52+/-0.04 mg/L, when concentrations of Tet were 0 mg/L, 0.5 mg/L, 1.0 mg/L, and 2.0 mg/L respectively). The gene encoding sorcin was highly expressed in K562/A02 cells, the expression of which was firstly enhanced in Tet concentration 0.5 mg/L, then attenuated in Tet concentration of 1.0, 2.0 mg/L (p<0.05). Sorcin protein expressed lowly in K562 cells and highly in K562/A02 cells, but the expression of SORCIN protein in K562/A02 cells was enhanced in Tet concentration of 0.5 mg/L, then was attenuated in Tet concentration of 1.0, 2.0 mg/L (p<0.05). It is concluded that the effect of Tet on reversal of K562/A02 drug-resistance shows concentration dependence by MTT assay. Tet reverses multidrug-resistance of K562/A02 cells through regulation of expression of SORCIN gene and protein, but not fully correlates to the reversing effect.