The Role and Mechanism of MiR-451 in Multidrug Resistance of Leukemia Cell Line K562/A02 / 中国实验血液学杂志

OBJECTIVE@#To detect the differential expressions of miR-451, ABCB1 and ABCC2 in drug-sensitive leukemia cell line K562 and drug-resistant cell line K562/A02, and explore the regulatory relationship between miR-451 and the expressions of ABCB1 and ABCC2 , and the mechanism of miR-451 involved in drug resistance in leukemia.@*METHODS@#CCK-8 assay was used to detect the drug resistance of K562/A02 and K562 cells. Quantitative Real-time PCR (qRT-PCR) was used to verify the differential expressions of miR-451 in K562 and K562/A02 cells. MiR-451 mimic and negative control (miR-NC), miR-451 inhibitor and negative control (miR-inNC) were transfected into K562 and K562/A02 cells respectively, then qRT-PCR and Western blot were used to detect the expression levels of mRNA and protein of ABCB1 and ABCC2 in K562 and K562/A02 cells and the transfected groups.@*RESULTS@#The drug resistance of K562/A02 cells to adriamycin was 177 times higher than that of its parent cell line K562. Compared with K562 cells, the expression of miR-451 in K562/A02 cells was significantly higher (P <0.001), and the mRNA and protein expression levels of ABCB1 and ABCC2 in K562/A02 cells were significantly higher than those in K562 cells (P <0.001). After transfected with miR-451 inhibitor, the expression of miR-451 was significantly down-regulated in K562/A02 cells (P <0.001), the sensitivity to chemotherapy drugs was significantly enhanced (P <0.05), and the mRNA and protein expressions of ABCB1 and ABCC2 were significantly decreased (P <0.01). After transfected with miR-451 mimic, the expression of miR-451 was significantly upregulated in K562 cells (P <0.001), and the mRNA and protein expressions of ABCB1 and ABCC2 were significantly increased (P <0.01).@*CONCLUSION@#There are significant differences in the expressions of miR-451, ABCB1 and ABCC2 between the drug-sensitive leukemia cell line K562 and drug-resistant cell line K562/A02, which suggests that miR-451 may affect the drug resistance of leukemia cells by regulating the expression of ABCB1 and ABCC2.

Screen of phosphopeptide specific for acute leukemia / 中华血液学杂志

<p><b>OBJECTIVE</b>To screen phosphopeptide specific for acute leukemia.</p><p><b>METHODS</b>Mononuclear cells from bone marrow were collected from 16 newly diagnosed acute lymphoblastic leukemia (ALL) and 20 acute myeloid leukemia (AML) patients. Peptides were extracted and purified, analyzed by immunoprecipitation and liquid chromatography coupled with tandem mass spectrometry (LC-MS).</p><p><b>RESULTS</b>(1) Non-receptor tyrosine kinase family members Fyn, Yes, Src widely expressed in acute leukemia; (2) Some phosphopeptides, including non-receptor tyrosine kinase family members Abl/iso1 and Abl, non-receptor Ser/Thr protein kinase family members Bcr, JNK2, JNK2 iso2, Adaptor/scaffold members Cas-L, Cbl, CrkL CENTD1 (Centaurin delta1) ZO2, transcriptor GFR-1 and phosphatase SHIP-2 were detected in Ph positive ALL, but not in other kinds of ALL. (3) Hck, Lyn and Fgr selectively expressed in AML (except AML-M(3)).</p><p><b>CONCLUSION</b>Some phosphopeptides were specific for ALL and AML, and may be useful for diagnosis and therapy of acute leukemia.</p>

Screening for drug resistance related microRNAs in K562 and K562/A02 cell lines / 中华血液学杂志

<p><b>OBJECTIVE</b>To explore the relationship between microRNA and drug resistance in leukemia treatment by screening and identifying the microRNAs which differentially express in K562 cell line and its adriamycin resistant cells-K562/A02 cell line.</p><p><b>METHODS</b>The drug resistance potency of K562/A02 cells was evaluated by MTT assay. P-gp expression of K562 and K562/A02 cells were detected by flow cytometry (FCM). The differentially expressed microRNAs in K562 and K562/A02 cells were analyzed by microarray technique and Real Time RT-PCR.</p><p><b>RESULTS</b>The resistance to adriamycin (ADM) of K562/A02 cells was 180 fold greater than that of K562 cells. P-gp expression rate of K562 and K562/A02 cells was 0.2% and 86%, respectively. Twenty-two microRNAs expressed differentially in K562 and K562/A02 cells (P < 0.01). As compared to K562 cells, expressions of miR-221, miR-155 and miR-451 were up-regulated by more than two fold, while expression of miR-98, miR-181a, let-7f, let-7g, miR-424 and miR-563 down-regulated by more than two fold in K562/A02 cells. The results of real time RT-PCR were consistent with that of microarray. Of note, differential expressions of miR-451, miR-155, miR-221, let-7f and miR-424 were remarkable.</p><p><b>CONCLUSION</b>K562/A02 cells show a different microRNA expression profile as compared to its parental K562 cells, suggesting microRNAs including miR-221, miR-155, miR-451, let-7f and miR-424 may be involved in the mechanism of drug resistance in leukemia. These differentially expressed microRNAs provide potential novel targets for overcoming drug-resistance.</p>

Clinical analysis of histocytic necrotizing lymphadenitis / 中南大学学报(医学版)

OBJECTIVE@#To understand the clinical features and histopathology of histocytic necrotizing lymphadenitis (HNL) so as to better recognize the disease.@*METHODS@#The clinical features, histopathology, and diagnosis of 10 patients admitted to our hospital were retrospectively analyzed.@*RESULTS@#The clinical features of these 10 cases included: young females were the majority; lymphadenopathy and fever were the most common clinical manifestations; some cases were accompanied by connective tissue diseases. Histopathologic examination showed distinctive necrosis and around the necrotic foci, variable proliferations of histocytes but generally without infiltration of neutrophils.@*CONCLUSION@#HNL has some typical histopathological alterations and relatively fine prognosis,but it tends to be misdiagnosed as lymphoma or lymphoid tuberculosis and may be accompanied by other diseases.

The dynamic analysis and the clinical significance of vascular endothelial cell markers and hemolysis parameters in thrombotic thrombocytopenic purpura / 中华血液学杂志

<p><b>OBJECTIVE</b>To monitor the changes of hemolysis parameters and endothelial cell markers in thrombotic thrombocytopenic purpura (TTP) and reveal the clinical significance of these changes.</p><p><b>METHODS</b>vWF-cleaving protease (vWF-CP) activity in 3 cases of TTP was detected by Western blot. The percentages of fragmented red cells (FRC) were counted throughout the entire clinical course. Levels of plasma thrombomodulin were detected by Western blot combined with density screening in TTP and healthy individuals (n = 3). Concentration of plasma VEGF was measured by enzyme-linked immunosorbent assay in TTP and healthy individuals (n = 9). Fundus fluorescein angiography was performed to search the evidence of microvascular thrombosis in one TTP patient with impaired visual acuity.</p><p><b>RESULTS</b>The lower vWF-CP activity was observed in TTP patients; the percentages of FRC in 3 cases of TTP were 1.65%, 2.50%, 3.32% respectively with an average of 2.49% at the onset of and decreased with the improvement of the disease. The levels of plasma TM and VEGF were significantly elevated in TTP than those in healthy individuals, and related to the severity of TTP. Fundus photography in one TTP patient with impaired visual acuity revealed vascular occlusion in fundus arteriole and venulae.</p><p><b>CONCLUSIONS</b>A decreased vWF-CP activity is in favour of TTP diagnosis. Dynamic monitoring of plasma TM and VEGF as well as percentages of FRC are useful indexes for reflecting the severity and evaluating therapeutic response of TTP. Selective fundus fluorescein angiography is useful for the judgement of microvascular thrombosis in TTP.</p>

Upregulation and activation of caspase-3 or caspase-8 and elevation of intracellular free calcium mediated apoptosis of indomethacin-induced K562 cells / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>A nonsteroidal anti-inflammatory drug, indomethacin, has been shown to have anti-leukemic activity and induce leukemic cell apoptosis. This study was to elucidate the mechanism of indomethacin-induced K562 cell apoptosis.</p><p><b>METHODS</b>K562 cells were grown in RPMI 1640 medium and treated with different doses of indomethacin (0 micromol/L, 100 micromol/L, 200 micromol/L, 400 micromol/L, 800 micromol/L) for 72 hours. The cells were harvested, and cell viability or apoptosis was analyzed using MTT assay and AO/EB stain, combining laser scanning confocal microscopy (LSCM) technique separately. For the localization and distribution of intracellular caspase-3 or caspase-8 protein, immunofluorescence assay was carried out. To reveal the activation of caspase-3 or caspase-8 in indomethacin-treated cells, Western blot detection was used. The change in intracellular free calcium was determined by Fluo-3/Am probe labeling combined with LSCM.</p><p><b>RESULTS</b>Indomethacin could lead to K562 cell apoptosis and inhibit cell viability in a concentration-dependent manner. An increased expression of intracellular caspase-3 or caspase-8 was observed at higher doses of indomethacin (400 - 800 micromol/L). Western blot results showed upregulation and activation in both caspase-3 and caspase-8 protein. Under indomethacin intervention, the levels of intracellular free calcium showed a significant increase. Blocking the activity of cyclooxygenase did not abolish the effects of indomethacin on K562 cell apoptosis.</p><p><b>CONCLUSIONS</b>Activation and upregulation of caspase-3 or caspase-8 protein were responsible for Indomethacin-induced K562 cell apoptosis. Variation of intracellular free calcium might switch on the apoptotic pathway and the proapoptotic effect of indomethacin might be cyclooxygenase-independent.</p>

Heparin cofactor II (HCII) activity and antigen assay and their significance in thrombotic diseases / 中华血液学杂志

<p><b>OBJECTIVE</b>To study the plasma HCII activity and antigen level variations and their relationship with arterial and deep venous thrombotic diseases.</p><p><b>METHODS</b>Seventy-five patients with brain infarction (BI), 50 myocardial infarction (MI), 36 deep venous thromboembolic disease (DVT) and 50 healthy controls were entered in this study. Plasma HCII activity was measured with chromogenic substrate method and the HCII antigen level by Western blotting assay. Plasma antithrombin (AT) activity was detected for the HCII deficiency individuals with DVT using chromogenic substrate method.</p><p><b>RESULTS</b>There was no significant difference in the mean plasma HCII activity and antigen levels between BI group [(99.97 +/- 21.14)% and 0.96 +/- 0.24], MI group [(98.18 +/- 29.35)% and 0.95 +/- 0.20] and healthy controls [(96.80 +/- 20.11)% and 0.93 +/- 0.19]. The plasma HCII activity and antigen concentrations in patients with DVT [(89.57 +/- 17.12)% and 0.87 +/- 10.18] tended to be decreased as compared with healthy controls, but they were not significant. No significant difference was found for the prevalence of HCII deficiency between patient groups and control group. The HCII deficiency individuals with DVT had normal AT activity and fibrinogen concentration.</p><p><b>CONCLUSIONS</b>Plasma HCII deficiency may not be the risk factor for arterial thrombosis in the Han population of Hunan Chinese. It is needed to further confirm if decreased plasma HCII is correlated with venous thrombosis.</p>