Proliferation Of Leukemia K562 Cells Research Articles

The role of chlorine atom on the binding between acrylonitrile derivatives and fat mass and obesity-associated protein.

In this work, seven acrylonitrile derivatives were selected as potential inhibitors of fat and obesity-related proteins (FTO) by the aid of fluorescence spectroscopy, ultraviolet visible spectroscopy, molecular docking, and cytotoxicity methods. Results show that the interaction between 3-amino-2-(4-chlorophenyl)-3-phenylacrylonitrile (1a) and FTO was the strongest among these derivatives. Thermodynamic analysis and molecular modeling show that the main force between 1a and FTO is hydrophobic interaction. The cytotoxicity test showed that the IC50 value of 1a was 46.64 μmol/L, which indicated 1a had the smallest IC50 value and had the best inhibitory effect on the proliferation of leukemia K562 cells among the seven derivatives. Both our previous results and this work show that chlorine atoms play important role in the binding of small molecules and FTO. This work brings new information for the study of FTO inhibitors.

Effect of dehydrocostus lactone on the proliferation of chronic myeloid leukemia K562 cells and its mechanism

Objective To explore the effect of dehydrocostus lactone on the proliferation of chronic myeloid leukemia cell line K562 and its mechanism. Methods K562 cells in logarithmic growth phase were treated with different concentrations of dehydrocostus lactone. Cell morphology was observed by Wright-Giemsa staining. Cell proliferation was detected by CCK-8 method. Cell cycle, apoptosis and the expressions of cell surface differentiation antigen CD14 and CD11b were detected by flow cytometry. JAK-STAT pathway and the expressions of apoptosis and cell cycle related proteins were detected by Western blot. Results Compared with the control group, the proliferation of K562 cells could be inhibited after treatment with different concentrations (4.0, 6.0, 8.0, 10.0 and 12.0 μmol/L) of dehydrocostus lactone for 24 h, and the difference was statistically significant (F = 109.510, P < 0.05). After treatment with 5.0 and 10.0 μmol/L dehydrocostus lactone for 24 h, the apoptosis rates of K562 cells were (16.1±3.8)% and (29.6±4.3)%, which were higher than that of the control group [(3.1±0.5)%] (F = 83.255, P < 0.05). After treatment with 5.0 and 10.0 μmol/L dehydrocostus lactone for 24 h, the proportion of G2/M phase cells in K562 cells were (17.0±3.2)% and (28.8±3.9)%, which were higher than that of the control group [(9.1±2.3)%] (F = 161.598, P < 0.05); the proportion of S phase cells in K562 cells were (48.1±3.9)% and (61.0±5.4)%, which were higher than that of the control group [(39.6±3.6)%] (F = 192.356, P < 0.05). After treatment with 2.5 and 5.0 μmol/L dehydrocostus lactone for 72 h, the expression rates of CD14 in K562 cells were (28.6±3.9)% and (41.1±4.4)%, which were higher than that in the control group [(3.1±0.5)%] (F = 132.811, P < 0.05); the expression rates of CD11b in K562 cells were (42.4±5.0)% and (61.2±5.7)%, which were higher than that in the control group [(4.2±1.1)%] (F = 179.553, P < 0.05). Dehydrocostus lactone could decrease the expressions of JAK2, STAT5, cyclin E, CDK2, cyclin A, CDC25C, cyclin B1, CDK1 and bcl-2 proteins, and up-regulate the expressions of p21 and bax proteins. Conclusion Dehydrocostus lactone can inhibit the proliferation of chronic myeloid leukemia K562 cells, which may be achieved by cell cycle arrest, induction of apoptosis and differentiation. Key words: Dehydrocostus lactone; Cell cycle; Apoptosis; Differentiation; Leukemia

Effect of dihydroartemisinin on the expression of BCR/ABL fusion gene in leukemia K562 cells

To investigate the effect of dihydroartemisinin (DHA) on the BCR/ABL fusion gene in leukemia K562 cell. K562 cells were cultured in vitro. The rate of proliferation inhibition of cells treated with various concentrations of DHA were determined by using [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] (MTT) method. Expression of BCR/ABL fusion gene was analyzed by reverse transcription(RT-PCR) before and after DHA treatment. Apoptosis of K562 cells was detected by flow cytometry. The growth of K562 cells was inhibited when the concentrations of DHA were 10-160 umol/L. With the added dose of DHA, the growth inhibition was remarkable, with the rate of inhibition risen from 52.76% to 94.65%. The expression of BCR/ABL fusion gene, as detected by RT-PCR after incubating the K562 cells with 20 umol/L DHA, measured as ΔCt = 4.45 ± 0.25 after 12 h and ΔCt = 5.23 ± 0.21 after 24 h, which was significantly lower compared with that of the control ( ΔCt = 4.23 ± 0.21, P < 0.05). DHA can inhibit the proliferation of leukemia K562 cells and facilitate the induction of apoptosis by downregulating the expression of BCR/ABL fusion gene.

Dihydroartemisinin induces autophagy and inhibits the growth of iron-loaded human myeloid leukemia K562 cells via ROS toxicity

Dihydroartemisinin (DHA), an active metabolite of artemisinin derivatives, is the most remarkable anti-malarial drug and has little toxicity to humans. Recent studies have shown that DHA effectively inhibits the growth of cancer cells. In the present study, we intended to elucidate the mechanisms underlying the inhibition of growth of iron-loaded human myeloid leukemia K562 cells by DHA. Mitochondria are important regulators of both autophagy and apoptosis, and one of the triggers for mitochondrial dysfunction is the generation of reactive oxygen species (ROS). We found that the DHA-induced autophagy of leukemia K562 cells, whose intracellular organelles are primarily mitochondria, was ROS dependent. The autophagy of these cells was followed by LC3-II protein expression and caspase-3 activation. In addition, we demonstrated that inhibition of the proliferation of leukemia K562 cells by DHA is also dependent upon iron. This inhibition includes the down-regulation of TfR expression and the induction of K562 cell growth arrest in the G2/M phase.

STAT5 in regulation of chronic leukemia K562 cell proliferation: Inhibitory effect of WHI-P131

In this study, we examined the role of JAK/STAT signaling in the regulation of chronic leukemia K562 cell proliferation. STAT3 and STAT5 tyrosine phosphorylation was used as a marker of the activation status of STAT proteins. We demonstrated that, in growing cultures of K562 cells, both STAT3 and STAT5 are constitutively activated. To determine the significance of STAT activity in maintaining the high level of K562 proliferation, we tested two JAK inhibitors, AG-490 (JAK2 and JAK3 inhibitor) and WHI-P131 (a new specific JAK3 inhibitor). We showed that, during the prolonged cultivation (48 h) of K562 cells with AG-490 or WHI-P131, the cells remained viable. It was found that treatment with WHI-P131 (30–100 μM) decreased tyrosine phosphorylation of STAT5 and did not affect the high level of STAT3 phosphorylation. In proliferating K562 cells, AG-490 (25–50 μM) did not influence on STAT3 and STAT5 phosphorylation. The flow cytometry analysis revealed a dose-dependent decrease in G1 and S phases and an increase in G2/M phases in WHI-P131-treated K562 cells and no changes in cell cycle structure in AG-490-treated cultures. Thus, our findings indicate the preferential role of STAT5 (not constitutively active STAT3) in the proliferation of leukemia K562 cells and demonstrate the specificity of WHI-P131 inhibitory effect; unlike other JAK drugs that stimulate apoptosis and decrease proliferation, WHI-P131 prevents K562 cells growth by arresting in G2/M phases of the cell cycle.