Background and purpose:Remarkable advances have been made in cancer chemotherapy by developing new anticancer drugs and therapy strategies.However,multidrug resistance in human cancers remains a major clinical challenge for cancer treatment.Attempts in several clinical studies to reverse multidrug resistance protein (MDR) by using MDR modulators have not yet generated promising results.Our aim was to explored the mechanism of reversal of multidrug resistance in human leukemia K562 cells by PI3-K inhibitor.Methods:Trypanblue dye exclusion method was used to observe the drug sensitivity and the effect of LY294002 on the drug resistance.Western blot to analyze P-gp and p-Akt phenotypes,and flow cytometer was used to measure the intracellular drug accumulation. Results:K562/D induced by DNR was cross resistant to DNR,ADR,VCR and VP16 (Resistance Index:65,52,134 and 50 respectively).DNR induced over-expressions of P-gp and p-Akt in K562/D cells;LY294002 increased the intracellular drug accumulation,and then reversed the drug resistance to DNR,ADR,VCR and VPI6 in K562/D cells(Resistance Index:23,21,63 and 29 respectively),but not in the sensitive cells (K562/S).Conclusion:The multidrug resistance of K562/D cells can be induced by DNR which is related to the P-gp and p-Akt over-expressions, and LY294002 can reverse multidrug resistance in human leukemia cells in vitro via inhibits PI3-K/Akt pathway.

The study was aimed to explore the mechanism of SYK and CBL family of ubiquitin ligases in Bufalin-induced HL-60 cells apoptosis. Cell viability was tested by trypan blue staining and apoptosis was detected by using flow cytometry. The expressions of CBL and CBL-b and the phosphorylation of SYK were detected by using immunoprecipitation and Western blot. The results showed that Bufalin inhibited HL-60 cell proliferation in time- and dose-dependent manners. IC(50) of suppressing cell viability at 24, 48 and 72 hours were about 26.3, 7.8 and 2.0 nmol/L respectively. The high dose of bufalin already induced apoptosis of HL-60 cells at 8 hours. SYK was quickly phosphorylated, and the expressions of CBL and CBL-b were down-regulated after treatment with Bufalin. It is concluded that SYK activation and CBL protein down-regulation may be involved in Bufalin-induced HL-60 cell apoptosis.
Apoptosis ; drug effects ; Bufanolides ; pharmacology ; Cell Proliferation ; drug effects ; Down-Regulation ; Gene Expression Regulation, Leukemic ; HL-60 Cells ; Humans ; Intracellular Signaling Peptides and Proteins ; metabolism ; Protein-Tyrosine Kinases ; metabolism ; Proto-Oncogene Proteins c-cbl ; metabolism ; Signal Transduction ; Syk Kinase

BACKGROUNDAmong patients with advanced multivessel coronary disease, left ventricular (LV) function is widely variable, and clinical and angiographic correlates of ventricular dysfunction remain to be defined.

METHODSAmong 73 339 patients undergoing diagnostic cardiac catheterization at a single center in China, patients with left ventriculographic assessment were identified with three-vessel coronary disease with or without left main involvement. Clinical and angiographic characteristics were examined among patients with normal or varying extent of LV dysfunction, and predictors of LV impairment (ejection fraction (EF): < 25%, 25% - 40% or > 40%) were determined.

RESULTSAmong 11 950 patients identified with three-vessel coronary disease, the sample distribution of LVEF was > 40%, n = 10 776; 25% - 40%, n = 948; < 25%, n = 226. Patients with reduced LV function (< 40%) more commonly were male and had a history of myocardial infarction (MI), diabetes or unstable angina. Hypertension was more frequent in those with LVEF ≥ 40%. In a multivariate Logistic regression analysis, prior MI (odds ratio (OR), 3.37; 95% confidence interval (CI), 2.96 - 3.84) was most predictive of LVEF < 40%, followed by male gender, diabetes, and presentation with unstable angina. For LVEF < 25%, only prior MI was identified as a significant correlate of severe LV dysfunction (OR 4.06, 95%CI 3.06 - 5.39). Following exclusion of patients with previous MI (n = 7416), male gender and diabetes were predictive of LVEF < 40%, yet presentation with unstable angina was the only factor significantly associated with LVEF < 25%.

CONCLUSIONAmong individuals identified with three-vessel coronary disease with or without left main involvement, previous MI was the most significant risk factor of LV dysfunction.

Aged ; Coronary Angiography ; Coronary Disease ; pathology ; physiopathology ; Female ; Humans ; Male ; Middle Aged ; Ventricular Dysfunction, Left ; pathology ; physiopathology

OBJECTIVETo analyze the mutation rate and clinical characteristics of CALR, MPL W515K and JAK2 V617F genes in patients with primary thrombocythemia (PT).

METHODSFifty-six patients with PT were selected as the research objects in our hospital. The CALR and MPL W515K gene mutations were determined by genomic DNA-PCR direct sequencing of the PCR products, and the JAK2 V617F gene mutation was detected by allele specific PCR method.

RESULTSAmong the 56 patients with PT there were 14 cases of CALR gene mutation with the incidence rate of 25%, including 6 cases of type I, 5 cases of type II and 3 cases of type III. The sex, age, platelet(Plt) count, white blood cell (WBC) count and hemoglobin (Hb) level in the type I case of CALR gene mutation all were not significantly different from that in type II and III(all P>0.05); the WBC level in type III group significantly increased in comparison of type II group (P<0.05), while the sex, age, Hb and Plt levels showed no significant difference between the type III and type II groups (P>0.05). There were 3 cases of MPL W515K gene mutation with the incidence rate of 5.36%; 21 cases of JAK2 V617F gene mutation with the incidence rate of 37.50%. There were 13 cases of CALR gene mutation in negative patients with MPL W515K and JAK2 V617F (18 cases) with 72.22% incidence rate (13/18), and there was no cases of 1 or 2 gene mutations coexisted. The levels of Hb and WBC in peripheral blood of patients with CALR mutation were significantly lower than those of JAK2 V617F mutation (both P<0.05). In 56 cases, there were 3 cases of abnormal karyotype, with the incidence rate of 5.36%. The mutation rate of CALR gene in abnormal karyotypes (66.67%) was significantly higher than that of normal karyotypes (20.75%) (P<0.01).

CONCLUSIONThe incidence of JAK2 V617F gene mutation increases in the patients with primary thrombocythemia; CALR mutation rate is higher in the patients with negative MPL W515K and JAK2 V617F gene mutation, which may closely correlate with abnormal karyotype; the levels of peripheral Hb and WBC in PT the patients with CALR gene mutation are significantly lower than those in patients with JAK2 V617F mutation.

Calreticulin ; Humans ; Janus Kinase 2 ; Mutation ; Mutation Rate ; Receptors, Thrombopoietin ; Thrombocythemia, Essential