Inhibition of NF-kappaB by mutant IkappaBalpha enhances TNF-alpha-induced apoptosis in HL-60 cells by controlling bcl-xL expression / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The aim of this study was to explore whether the inhibition of nuclear factor-kappaB (NF-kappaB) activation by mutant IkappaBalpha (S32, 36-->A) can enhance TNF-alpha-induced apoptosis of leukemia cells and to investigate the possible mechanism.</p><p><b>METHODS</b>The mutant IkappaBalpha gene was transfected into HL-60 cells by liposome-mediated techniques. G418 resistant clones stably expressing mutant IkappaBalpha were obtained by the limiting dilution method. TNF-alpha-induced NF-kappaB activation was measured by electrophoretic mobility shift assay (EMSA). The expression of bcl-xL was detected by RT-PCR and Western blot after 4 hours exposure of parental HL-60 and transfected HL-60 cells to a variety of concentrations of TNF-alpha. The percentage of apoptotic leukemia cells was evaluated by flow cytometry (FCM).</p><p><b>RESULTS</b>Mutant IkappaBalpha protein was confirmed to exist by Western blot. The results of EMSA showed that NF-kappaB activation by TNF-alpha in HL-60 cells was induced in a dose-dependent manner, but was almost completely inhibited by mutant IkappaBalpha repressor in transfected cells. The levels of bcl-xL mRNA and protein in HL-60 cells increased after exposure to TNF-alpha, but changed very little in transfected HL-60 cells. The inhibition of NF-kappaB activation by mutant IkappaBalpha enhanced TNF-alpha-induced apoptosis. The cytotoxic effects of TNF-alpha were amplified in a time- and dose-dependent manner.</p><p><b>CONCLUSIONS</b>NF-kappaB activation plays an important role in the resistance to TNF-alpha-induced apoptosis. The inhibition of NF-kappaB by mutant IkappaBalpha could provide a new approach that may enhance the anti-leukemia effects of TNF-alpha or even of other cytotoxic agents.</p>

Activity of telomerase and extracellular regulated protein kinases in parental and drug resistant cells of leukemia and ovarian cancer / 中国实验血液学杂志

In order to study the role of telomerase and extracellular regulated protein kinase (ERK) in drug-resistance of leukemia and ovarian cancer cells, telomeric repeat amplification protocol (TRAP) assay and bioluminescence analysis were used for qualitative analysis or quantitative detection of telomerase activity respectively, and Western blot was used to detect the expression level of phosphorylatedly activated ERK(1) and ERK(2) protein in the parental and drug resistant cells of leukemia and ovarian cancer. In addition, chemotherapy sensitivity to HRT or DDP was evaluated by MTT assay. The difference of cell cycle distribution between parental cell and drug-resistant cell was analyzed by flow cytometry. The results showed that the drug resistant cells were of higher percentage in G(0)/G(1) phase compared with the parental cell lines. Telomerase activity and phosphorylatedly activated ERK(1) and ERK(2) protein expression level were higher in drug-resistant cells than in parental cell. It is suggested that the increasing number of the drug resistant cells in G(0)/G(1) phase may be considered as a sign of drug resistance. The up-regulation of telomerase activity and phosphorylatedly activated ERK(1) and ERK(2) protein expression level may play an important role in drug resistance of leukemia and ovarian cancer cell lines.

Mild type of hemophilic pseudotumor with injury of femoral nerve (one case report) / 中国实验血液学杂志

To explore the diagnoses and treatment of hemophilic pseudotumor, one case with hemophilic pseudotumor misdiagnosed and treated by operation, was observed and analyzed. The result showed that the final diagnosis of this case was following: hemophilia A (mild type) and hemophilic pseudotumor with injury of femoral nerve. The final diagnosis was given from inquiring case history and family history additionally, and drawing assistance from laboratory examination and computed tomography. After operation, the patient's wound healed very well through supplying coagulation factors positively. In conclusion, it was important for inquiring case history and family history particularly and thinking highly of laboratory examination to reduce the misdiagnosis and error of therapy for this case. If paying attention to preoperative preparation, the danger of hemorrhage during operation can be reduced and wound after operation can heal more rapidly.

Influence of antisense oligonucleotide targeting Chk1/2 on apoptosis of K562 cell induced by DDP / 中国实验血液学杂志

In order to investigate the change of cell-cycle of K562 cells induced by cisplatin (DDP) and role of antisense oligonucleotide targeting Chk1/2 on apoptosis of K562 cell induced by DDP, the change of cell-cycle was observed by means of flow cytometry after different intervals in which the K562 cell were treated by DDP. Chk1/2 protein expression was investigated by Western blot and confocal microscopy in best condition of transfection of antisense oligonucleotide targeting Chk1/2 by lipofection. Apoptosis of K562 induced by DDP was investigated by flow cytometry after transfection of antisense oligonucleotide targeting Chk1/2. The results showed that K562 cells were arrested at S phase at 10 micromol/L of DDP. Transfection with antisense oligonucleotide targeting Chk1/2 could inhibit expression of Chk1/2 at different levels. The frequency of apoptosis induced by DDP was increased when transfected with antisense oligonucleotide targeting Chk1 and/or Chk2. The effect of antisense oligonucleotide targeting Chk1 and Chk2 synchronously exceeded that of antisense oligonucleotide targeting either Chk1 or Chk2 alone. In conclusion, Chk1 and Chk2 may be regarded as targets of therapy for leukemia.

To inhibit ERK for enhancing chemotherapy sensitivity of drug-resistance cell lines of leukemia and ovarian carcinoma / 中国实验血液学杂志

The aim was to study the roles of extracellular regulated protein kinases (ERK) and telomerase activity in drug resistance of human leukemia and ovarian carcinoma cells. Flow cytometry was used to analyze apoptosis rate. Telomere repeat amplification protocol (TRAP) and bioluminescence analysis method were used for detection of telomerase activity. The phosphorylated ERK(1/2) protein expression was observed by Western blot method. The results showed that the specific inhibitor PD98059 of ERK kinase 1 (MEK(1)) enhanced the sensitivity of HL-60/E6 leukemia cell lines to harringtonine (HRT) or COC1/DDP ovarian carcinoma cell lines to cis-dichlorodiamine platinum (DDP). Both PD98059 and chemotherapy drugs HRT and DDP reduced the phosphorylated ERK(1) and ERK(2) protein expression level, and down-regulated the telomerase activity. The sole action of each was inferior to the combination action of PD98059 and HRT or DDP. In conclusion, ERK and telomerase serve a function to some extent in drug resistance of leukemia and ovarian carcinoma cells. The inhibition of ERK signal transduction pathways led to reduction of phosphorylated ERK(1) and ERK(2) protein expression level, and successionally down-regulated the telomerase activity. The final result was to enhance the sensitivity of HL-60/E6 to HRT or COC1/DDP to DDP.

Regulative function of extracelluar regulated protein kinases and telomerase in apoptosis of hepatocarcinomatous cell SMMC-7721 / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To study the changes of telomerase activity and protein expression of phosphorylated (activated) extracellular regulated protein kinases (ERK1 and ERK2) in the course of inhibiting hepatocarcinomatous cell proliferation and inducing cell apoptosis by three kinds of chemotherapy drugs: Harringtonine (HRT), Vincristine (VCR), and Etoposide (Vp16). To discuss the regulative function to hepatocarcinomatous cell apoptosis and interrelation of telomerase and ERK.</p><p><b>METHODS</b>Cytotoxicity assay, flow cytometry analysis, telomerase repeat amplification protocol assay (TRAP), bioluminescence analysis, and western blot were used in this experiment.</p><p><b>RESULTS</b>HRT, VCR, and Vp16 could inhibit cell proliferation (0.28% 0.08%, 0.25% 0.16%, 0.24% 0.11%), induce apoptosis (21.12%, 28.83%, 12.30%), inhibit telomerase activity, and down-regulate the protein expression of phosphorylated ERK.</p><p><b>CONCLUSIONS</b>It might be through ERK signal transduction pathways that chemotherapy drugs down-regulate telomerase activity and induce apoptosis.</p>

Regulative function of extracellular regulated protein kinases and telomerase in apoptosis of hepatocarcinomatous and leukemic cell lines / 中国实验血液学杂志

In order to investigate the change of telomerase activity and phosphorylated (activated) extracellular regulated protein kinases (ERK) 1 and 2 in hepatocarcinomatous cell line SMMC7721 and leukemic cell line K562 proliferation inhibition and apoptosis, three kinds of chemotherapeutic drugs harringtonine (HRT), vincristine (VCR) and etoposide (VP-16) were selected as inducers; and MTT assay, flow cytometry analysis, telomeric repeat amplification protocol (TRAP) assay and bioluminescence analysis were used. The results showed that after treatment of HRT, VCR and VP-16 for 24 hours, the cell proliferation was inhibited, apoptosis was induced, and telomerase activity and the protein expression of phosphorylated ERK1/2 were down-regulated. In HRT treated groups, the descendent grade was the most obvious. It was concluded that the common molecular mechanism of these chemotherapeutic drugs killing SMMC7721 and K562 cell lines might be through inhibiting ERK signal transduction pathways, cutting down ERK activity, reducing the transcription of target genes of ERKs, then indirectly down-regulate telomerase activity, and cell apoptosis is the final result of durative loss of telomere.

Antisense Oligodeoxynucleotide Directed to NF-kappaB-RelA Down-Regulates bcl-x(L) mRNA in Drug-Resistant Leukemia Cell Line HL-60/E6 / 中国实验血液学杂志

In order to explore the effect of nuclear factor-kappa B (NF-kappaB) on bcl-x gene transcrtiption in drug-resistant leukemia cell line HL-60/E6, first of all, drug-resistant subline HL-60/E6 was derived by intermittently exposing HL-60 cells to 6 ng/ml epirubicin, and then bcl-x(L) mRNA levels were detected by RT-PCR after exposing HL-60/E6 cells to 5 micro mol/L AS-PS-ODN-RelA at different times. Morever, indirect immuno-fluorescence and FCM were used to demonstrate the location of NF-kappaB-RelA in HL-60/E6 cells and the efficiency of liposome-mediated ODN transfection. The results showed that RelA kept active and located at the nuclei of HL-60/E6 cells, and the efficiency of liposome-mediated ODN transfection was significantly higher than that of null ODN (P < 0.01 in 4, 6 and 12 h). Exposure of HL-60/E6 cells to 5 micro mol/L AS-PS-ODN-RelA led to a maximal 40% decline of bcl-x(L) mRNA levels. No significant change of bcl-x(L) mRNA level occurred in control group. It was concluded that NF-kappaB was involved in regulating bcl-x transcription. Suppressing NF-kappaB-RelA by antisense technology may down-regulate level of bcl-x(L) mRNA.

Vascular Endothelial Growth Factor and Its Receptor KDR/flk-1 Play Important Roles in Hematopoiesis / 中国实验血液学杂志

It is widely accepted that hematopoietic and endothelial cell lineages are initiated from the same precursor cells (named as hemangioblast), although hemangioblast has not been proved. Vascular endothelial growth factor (VEGF) and its receptor KDR/flk-1 is a prime regulator of endothelial cell proliferation, angiogenesis, vasculogenesis and vascular permeability. It is speculated that VEGF and its receptor KDR/flk-1 may also play an important role in embryonic and postnatal hematopoiesis. But the exact role and mechanism are not well known. Some latest developed cellular and molecular techniques can be used to prove the existence of hemangioblast and to investigate its biologic feature and the effect of VEGF and receptor KDR/flk-1 on its biologic feature.

Influence of DDP and ADM on cell cycle and apoptosis in K562 cells / 中国病理生理杂志

AIM: To investigate the effect of DDP and ADM on cell cycle in leukemia cell line K562. METHODS: The change of cell cycle was observed by means of flow cytometry after different interval in which the K562 cells were treated with DDP and ADM. RESULTS: K562 cells attested at S phase after treated 36 hours with DDP at concentration of 10 ?mol/L or 48 h with ADM at concentration of 1 36 ?mol/L. K562 cells attested at G 1 phase after treated 24 h with DDP at concentration of 20 ?mol/L or at G 2/M phase after treated with ADM at concentration of 0 17 ?mol/L. CONCLUSIONS: K562 cells showed different patterns to change the cell cycle induced by DDP and ADM with different concentrations at different time, which reflected that different checkpoints of cell cycle were activated at different conditions.