Deregulated expression of Cdc6 as BCR/ABL-dependent survival factor in chronic myeloid leukemia cells.

Chronic myeloid leukemia is characterized by the presence of the reciprocal translocation t(9;22) and the BCR/ABL oncogene. The BCR/ABL oncogene activates multiple signaling pathways and involves the dysregulation of oncogenes during the progression of chronic myeloid leukemia. The cell division cycle protein 6, an essential regulator of DNA replication, is elevated in some human cancer cells. However, the expression of cell division cycle protein 6 in chronic myeloid leukemia and the underlying regulatory mechanism remain to be elucidated. In this study, our data showed that cell division cycle protein 6 expression was significantly upregulated in primary chronic myeloid leukemia cells and the chronic myeloid leukemia cell line K562 cells, as compared to the normal bone marrow mononuclear cells. BCR/ABL kinase inhibitor STI571 or BCR/ABL small interfering RNA could significantly downregulate cell division cycle protein 6 messenger RNA expression in K562 cells. Moreover, phosphoinositide 3-kinase/AKT pathway inhibitor LY294002 and Janus kinase/signal transducer and activator of transcription pathway inhibitor AG490 could downregulate cell division cycle protein 6 expression in K562 cells, but not RAS/mitogen-activated protein kinase pathway inhibitor PD98059 had such effect. Cell division cycle protein 6 gene silencing by small interfering RNA effectively resulted in decrease of proliferation, increase of apoptosis, and arrest of cell cycle in K562 cells. These findings have demonstrated that cell division cycle protein 6 overexpression may contribute to the high proliferation and low apoptosis in chronic myeloid leukemia cells and can be regulated by BCR/ABL signal transduction through downstream phosphoinositide 3-kinase/Akt and Janus kinase/signal transducer and activator of transcription pathways, suggesting cell division cycle protein 6 as a potential therapeutic target in chronic myeloid leukemia.

Cytotoxic effect of trans-cinnamaldehyde on human leukemia K562 cells.

AIM: To investigate the effects of trans-cinnamaldehyde (TCA) on the human leukemia K562 cell line and the cytotoxicity of cytokine-induced killer (CIK) cells against K562 cells. METHODS: Apoptosis, Fas expression, and mitochondrial transmembrane potential in K652 cells were analyzed using flow cytometry. K562 cells were labeled with CFSE. The cytotoxic effect of expanded CIK cells on CFSE-labeled K562 cells was determined by FACS flow cytometry. RESULTS: Treatment with TCA 180 micromol/L for 9 h induced apoptosis in 8.9%+/-1.23% of K562 cells. Treatment with 120 or 180 micromol/L TCA for 24 h significantly increased the apoptotic cells to 18.63%+/-1.42 % and 38.98%+/-2.74%, respectively. TCA significantly upregulates Fas expression and decreases mitochondrial transmembrane potential in K562 cells. TCA treatment at 120 and 180 micromol/L for 9 h enhanced the percentage of lysis of K562 cells by expanded CIK cells from 34.84%+/-2.13% to 48.21%+/-2.22 % and 64.81%+/-3.22% at the E:F ratio of 25:1 and from 49.26%+/-3.22% to 57.81%+/-5.13% and 73.36%+/-5.98% at E:F ratio of 50:1. CONCLUSION: TCA exerts cytotoxic effects on human leukemia K562 cells by inducing apoptosis and synergizing the cytotoxicity of CIK cells against K562 cells. These properties of TCA are beneficial to the treatment of leukemia, even in the patients who have received hematopoietic stem cells transplantation (HSCT).

Inhibition of plasminogen activator inhibitor type-1 expression in HepG2 cells by fenofibrate may be associated with Smad signaling.

BACKGROUND: We investigated the molecular mechanism underlying the effect of fenofibrate on expression of plasminogen activator inhibitor type-1 (PAI-1) in HepG2 cells. METHODS: Luciferase reporter gene plasmids containing four sequentially truncated fragments of the PAI-1 promoter region (-804 to +17) were constructed and plasmids carrying constructs of Smad binding element (SBE)-site-directed deletions in the PAI-1 promoter were also generated and then transfected to HepG2 cells prior to fenofibrate treatment. Smad3 and Smad4 protein levels were measured by Western blotting. RESULTS: The decreased expression of PAI-1 mRNA and protein was detected in HepG2 cells after exposure to fenofibrate. PAI-1 transcription activities were also down-regulated following exposure to fenofibrate in HepG2 cells when they were transfected with the luciferase reporter gene plasmid containing a full-length of PAI-1 promoter. However, with the truncation of PAI-1 promoter, the inhibitory effect of fenofibrate on the transcription activity of PAI-1 gradually diminished. Furthermore, the transcription activity of PAI-1 was significantly up-regulated by fenofibrate in HepG2 cells when they were transfected with plasmids of the SBEs-deleted PAI-1 promoter. The expression of both Smad3 and Smad4 proteins was suppressed by fenofibrate. CONCLUSION: Fenofibrate exerts its inhibitory effect on PAI-1 transcription in HepG2 cells presumably involving Smad signaling pathways.

[Analysis on clone in vitro and tumorigenic capacity in vivo of different subsets cells from the MCF-7 human breast cancer cell line].

OBJECTIVE: To investigate whether there are cancer stem cells in the MCF-7 human breast cancer cell line. METHODS: Flow cytometry was applied to separate different subpopulation cells from MCF-7 cells, and their ability of clone in vitro and reconstruction tumor in vivo were determined. RESULTS: The ability of clone in vitro and reconstruction tumor in vivo were observed in some MCF-7 cells. Contrast with CD44+ CD24+ cells, the proportion of tumorigenic cancer cells in CD44+ CD24- cells is higher. CONCLUSION: Breast cancer stem cell exists in MCF-7 and it mainly locates the subpopulation of CD44+ CD24- cells, CD44+ CD24+ cell possibly is breast cancer progenitor cell.

The alteration of plasminogen activator inhibitor-1 expression by linoleic acid and fenofibrate in HepG2 cells.

The present study investigated the influence of linoleic acid and fenofibrate on plasminogen activator inhibitor-1 (PAI-1) expression in HepG2 cells and the mechanism possibly involved. Using gene recombination techniques, chloromycetin acetyltransferase (CAT) reporter gene plasmids containing nuclear factor-kappaB response element deletion (del1-PAI-pCAT) or very-low-density lipoprotein/fatty acid response element deletion (del2-PAI-pCAT) in the PAI-1 promoter were constructed and transiently transfected into HepG2 cells, respectively. Linoleic acid and fenofibrate were added to induce the transfected cells. The PAI-1 expression in mRNA and protein level was significantly induced by linoleic acid, but suppressed by fenofibrate. In the HepG2 cells transfected with PAI-pCAT plasmid, the PAI-1 transcription activity was significantly induced by linoleic acid, but suppressed by fenofibrate. Under transfection with del1-PAI-pCAT, both linoleic acid and fenofibrate increased the PAI-1 transcriptional activity; whereas in those cells transfected with del2-PAI-pCAT, fenofibrate significantly reduced PAI-1 transcriptional activity but no change was found with linoleic acid stimulation. Peroxisome proliferator-activated receptor alpha may be one of transcription factors playing a role in the upregulation of PAI-1 gene expression by linoleic acid in HepG2 cells. The inhibition of the nuclear factor-kappaB signaling pathway may be involved in the downregulation of PAI-1 gene expression by fenofibrate.

Effects of chitosan and heparin on early extension of burns.

Chitosan, a naturally occurring high-molecular glycosaminoglycan (GAG), has been widely used in wound healing, including burns. Heparin is also a highly used glycosaminoglycan in burns. To evaluate the effects of chitosan and heparin alone and the mixture of chitosan and heparin on early extension of burn wound, deep partial-thickness burns were performed on the dorsum of rats. Then chitosan and heparin powder and the mixture of chitosan and heparin were applied, respectively, on the burn wounds. After 72 h, histological examination of the burn wounds was performed. Outcome showed that the burn degree of chitosan group was less severe than control group and chitosan greatly prevented the extension of burns in early phase. However, heparin had no protective effect on the early extension of burns. Use of chitosan and heparin together attenuated chitosan's protective effect.

[Effects of Lycium barbarum polysaccharide on tumor microenvironment T-lymphocyte subsets and dendritic cells in H22-bearing mice].

OBJECTIVE: To study the effects of Lycium barbarum polysaccharide (LBP) on tumor microenvironment T-lymphocyte subsets and dendritic cells in H22-bearing mice and the mechanisms for intervention of tumor immune escape by LBP. METHODS: H22-bearing mice were given LBP orally for two weeks. T-lymphocyte subsets and the phenotypes of dendritic cells in tumor-infiltrating lymphocytes (TIL) were detected by flow cytometry (FCM). RESULTS: LBP could significantly increase the numbers of CD4(+) and CD8(+) T cells in TIL as compared with those in model control group (P<0.05). In model control group, the number of dendritic cells in tumor microenvironment decreased markedly, while in LBP-treated group, the increased number of dendritic cells and B7-1 expression were observed, but there were no significant differences between these two groups. CONCLUSION: LBP has anti-tumor effect probably by increasing the numbers of CD4(+) and CD8(+) T cells in TIL to relieve the immunosuppression and enhance the anti-tumor function of the immune system. But whether LBP can recover the phenocyte and function of dendritic cells in H22-bearing mice should be further studied.

[Biological Effects of the SARI Over-expression on K562 Cell Line].

OBJECTIVE: To construct a lentivirus vector carrying SARI gene and to investigate its biological effects on K562 cells. METHODS: SARI was amplified from the plasmid containing SARI cDNA and subcloned into pLOV.CMV.eGFP virus vector. After sequencing, lentivirus packaging, titering, the viruses of SARI-pLOV.CMV.eGFP were harvested and tansfected into the K562 cells. Real-time quantitive PCR and Western blot were performed to validate the SARI expression at the level of mRNA and protein respectively. Simultaneously, the proliferation, apoptosis and cell cycle of K562 cells were detected by CCK-8 and flow cytometry respectively. RESULTS: The SARI overexpressed lentivirus vector was successfully constructed. The mRNA and protein levels of SARI increased significantly in the pLOV.CMV.eGFP-SARI group, which was confirmed by Q-PCR and Western blot; as compared with blank and mock groups, SARI over-expression leaded to significant proliferation inhibition and increased apoptosis of K562 cells, without visible effects on cell cycle. CONCLUSION: the over-expression of SARI gene obviously suppresses the cell proliferation of the K562 cells as well as promotes the apoptosis. The results implied that the induction of the SARI gene expression may be an important candidate therapeutic method for the CML.

Effect of peroxisome proliferator-activated receptor activators on tumor necrosis factor-alpha expression in neonatal rat cardiac myocytes.

OBJECTIVE: To investigate the effect of peroxisome proliferator-activated receptor-alpha (PPAR alpha) and PPAR gamma activators on tumor necrosis factor-alpha (TNFalpha) expression in neonatal rat cardiac myocytes. METHODS: Primary cultures of cardiac myocytes from 1- to 3-day-old Wistar rats were prepared, and myocytes were exposed to lipopolysaccharide (LPS) and varying concentrations of PPAR alpha or PPAR gamma activator (fenofibrate or pioglitazone). RT-PCR and ELISA were used to measure TNFalpha, PPAR alpha, and PPAR gamma expression in cultured cardiac myocytes. Transient transfection of TNFalpha promoter with or without nuclear factor-kappaB (NF-kappaB) binding site to cardiac myocytes was performed. RESULTS: Pretreatment of cardiac myocytes with fenofibrate or pioglitazone inhibited LPS-induced TNFalpha mRNA and protein expression in a dose-dependent manner. However, no significant changes were observed on PPAR alpha or PPAR gamma mRNA expression when cardiac myocytes were pretreated with fenofibrate or pioglitazone. Proportional suppression of TNFalpha promoter activity was observed when myocytes was transiently transfected with whole length of TNFalpha promoter (-721/+17) after being stimulated with LPS and fenofibrate or pioglitazone, whereas no change of promoter activity was observed with transfection of TNFalpha reporter construct in deletion of NF-kappaB binding site (-182/+17). CONCLUSIONS: PPAR alpha and PPAR gamma activators may inhibit cardiac TNFalpha expression but not accompanied by change of PPAR alpha or PPAR gamma mRNA expression. Therefore PPAR alpha and PPAR gamma activators appear to play a role in anti-inflammation. The mechanism may partly be involved in suppression of the NF-kappaB pathway.

[An exploratory study on mechanism of PPARalpha activators-induced plasminogen activator inhibitor-1 expression in HepG-2 cells].

OBJECTIVE: To investigate the influence of peroxisome proliferator-activated receptor alpha activators on plasminogen activator inhibitor-1 (PAI-1) expression in HepG-2 cells and the mechanism possibly involved. METHODS: Linoleic acid and fenofibrate were used in the treatment of HepG-2 cell culture. PAI-1 activity and mRNA expression were determined with colorimetric assay and reverse transcription-polymerase chain reaction, respectively. Using gene recombination techniques, two types of chloramphenicol acetyl transferase (CAT) reporter gene plasmid containing different deletions in PAI-1 promoter were constructed and transiently transfected into HepG-2 cells, respectively. Linoleic acid and fenofibrate were added to induce the transfected cells. CAT activity was measured to demonstrate the transcriptional activity of PAI-1 gene in HepG-2 cells. RESULTS: The mRNA expression and protein activity of PAI-1 was significantly induced by linoleic acid, but was obviously suppressed by fenofibrate. In the HepG-2 cells transfected with PAI-pCAT promoter constructs the PAI-1 transcription activity was significantly induced by linoleic acid, but suppressed by fenofibrate. The level of PAI-1 transcription was also significantly increased when co-transfected with PAI-pCAT promoter construct and PPAR alpha-pSG5 expression plasmid to HepG-2 cells. Furthermore, in the condition of transfection with NF-kappaB-response element-deletion-pCAT construct, both linoleic acid and fenofibrate increased the PAI-1 transcriptional activity, whereas in those cells transfected with VLDL/fatty acid response element-deletion-pCAT construct, fenofibrate significantly reduced PAI-1 transcriptional activity, but no change in PAI-1 transcription activity was found with linoleic acid stimulation. CONCLUSIONS: Linoleic acid induces PAI-1 activity and mRNA expression in HepG-2 cells. PPAR alpha may be one of transcription factors playing a role in the upregulation of PAI-1 gene expression. The inhibition of NF-kappaB signaling pathway may be involved in the downregulation of PAI-1 gene expression by fenofibrate.

Cross-lineage expression in 505 patients with acute lymphoblastic leukemia by multiparametric flow cytometry analysis.

The expression of immunological markers of one hematopoietic lineage on the abnormal cells of another lineage (cross-lineage expression) is a known feature of leukemia. The present study was aimed to investigate the cross-lineage expression in ALL cells. The cross-lineage expression in ALL cells from 505 patients was detected by flow cytometry using 23 monoclonal antibodies (McAbs) in triple staining combinations. The results showed that in whole ALL, the expression of myeloid antigens occurred in 56.4% of the cases, and CD13 was the most frequently expressed myeloid marker (32.7%) followed by CD33 (29.5%), CD15 (19.2%) and CD11b (7.7%). CD13/CD33 expressions were more frequent in CD34(+) cases than in CD34(-) cases. In B-ALL, T-cell antigen CD4, CD5, CD7 and CD2 were found in 27 (6.3%), 12 (2.8%), 8 (1.9%), and 6 (1.4%) cases respectively, and CD7(+), CD2(+) and CD4(+) cases commonly expressed CD13/CD33. In T-ALL, B-cell antigen cCD79a, CD19 and CD22 were found in 6 (8.1%), 5 (6.8%), and 2 (2.8%) cases respectively, and all of CD19(+) and CD22(+) cases were all accompanied with CD13/CD33. It is concluded that cross-lineage expression in ALL mostly exists in the immature stages, ALL cells more frequently express phenotypes B(+)M(+), T(+)M(+) and occasionally B(+)T(+)M(+), but B(+)T(+)M(-) phenotype is extremely rare.

[Effects of acute myeloid leukemia cell supernatant on the proliferation and apoptosis of CD4+ and CD8+ T cell subsets].

To study the effects of supernatant derived from acute myeloid leukemia (AML) cell lines on proliferation and apoptosis of CD4(+) and CD8(+) T cell subsets and to investigate the mechanism by which AML escapes from immune recognition, lymphocytes were labeled with CFSE and were stimulated with anti-CD3 and anti-CD28 in presence or absence of supernatants from three AML cell lines (HL-60, NB4, U937). After culture, cell suspensions were labeled with 7AAD and CD4 PE (or CD8 PE). Cells were then detected by flow cytometry and their proliferation and apoptosis were analyzed. The results showed that supernatants from two of three cell lines (HL-60 and NB4) inhibited the proliferation of CD4(+) and CD8(+) T cells, and the degree of inhibition showed a dose-dependent way. Similarly, the apoptosis of stimulated CD4(+) T cells was inhibited, but stimulated CD8(+) T cells remained unaffected by supernatant from HL-60 and NB4. In contrary, the apoptosis of proliferative CD8(+) T cells were increased significantly by HL-60 and NB4 supernatant. It is concluded that soluble factors derived from AML cell lines inhibit the proliferation of CD4(+) and CD8(+) T cells and induce the apoptosis of proliferative CD8(+) T cells, that may be one of the mechanisms by which the immunity was suppressed.

[Proliferation and apoptosis in vitro of umbilical cord blood CD34+CD38- hematopoietic early progenitor cells].

To cultivate CD34(+)CD38(-) cells isolated from umbilical cord blood of healthy puerperal women over a longer-period of time for observation of cell division, proliferation, apoptosis, and effects of stem cell factor on the growth of CD34(+)CD38(-) cells, with flow cytometry, CD34(+)CD38(-) cells were isolated from umbilical cord blood of 10 healthy puerperal women and cultivated in stem cell media with supplement of IL-3, IL-6, GM-CSF, EPO, IGF-1 and SCF 6 kinds cell growth stimulating factors for six months. The cell growth curves were established. The effects of stem cell factor on the growth of CD34(+)CD38(-) cells and cell apoptosis were investigated with the single cell gel electrophoresis technique and flow cytometry method, respectively. The results showed that CD34(+)CD38(-) cells isolated from umbilical cord blood were capable of proliferating after being cultivated in vitro over a longer-period of time with no evidence of the presence of excessive apoptosis. In conclusion, under appropriate culture conditions, CD34(+)CD38(-) hematopoietic early progenitor cells from umbilical cord blood can serve as a resource providing a large amount of primitive cells for transplantation therapy after a longer period of cultivation and proliferation in vitro.

[Correlation of immunophenotype to cytogenetics and clinical features of adult acute myeloid leukemia].

BACKGROUND & OBJECTIVE: New WHO classification has been rapidly used in diagnosis of leukemia. Based on coexpression and correlation of lineage-associated antigens, multiparameter high-resolution flow cytometry has been developed to precisely identify lineage characteristics of leukemia. Some immunophenotypes correlate with cytogenetic abnormality and prognosis. This study was to analyze immunophenotype of naive acute myeloid leukemia (AML), and explore its correlations to cytogenetics, clinical features, and FAB subtype of AML. METHODS: Multiparameter high-resolution flow cytometry with a panel of 25 different monoclonal antibodies was used to analyze the surface and cytoplasmic antigens expressions of 96 adults with AML; G-binding technique was used to analyze karyotype of 73 of the 96 patients. RESULTS: In these AML patients, some antigens were correlated with FAB subtypes:expression of CD2 was enhanced in AML-M3; HLA-DR, CD34, and CD56 were absent in AML-M3; expression of CD19 was increased in AML-M2; expressions of CD14 and CD56 were enhanced in AML-M5; MPO was absent in AML-M0. Karyotype abnormality was detected in 40(54.8%) patients. CD22, CD56, and TdT expressions were correlated with karyotype abnormality. t(8; 21) was only detected in 10 AML-M2 patients with high expressions of CD15, CD19, CD34, and CD56; no lymphoid lineage antigens were detected in 7 AML-M3 patients with t (15; 17). Expressions of CD4 and TdT were positively correlated with patient's age; expressions of CD7 and CD14 were positively correlated with high white blood cell count; expressions of CD4, CD14, and CD56 were positively correlated with high platelet count. CONCLUSIONS: The abnormal antigen expression of AML is tightly linked with karyotype abnormality. Detection of immunophenotype may help to diagnose and classify AML.

[Immunophenotypes in 115 patients with acute myeloid leukemia by multi-color flow cytometry].

Immunophenotyping has become common in the diagnosis and classification of leukemia. To evaluate the immunophenotype of acute myeloid leukemia (AML), multiparameter flow cytometry and CD45/SSC gating were used to analyze the surface and cytoplasmic antigen expressions in 115 cases of AML. The results were compared with the French-American-British (FAB) Cooperative Group classification to help define the best use and role of multiparameter flow cytometry in the diagnosis and proper classification of AML. The results showed that CD38, CD38 and CD13 were the most commonly expressed antigen (94.8%, 91.3% and 89.6%, respectively). CD7 was the most commonly expressed lymphoid antigen (20.2%), followed by CD19 (16.5%) and CD2 (15%). Some immunophenotypes correlated with FAB type, including increased frequency of CD2 in M(3); lack of HLA-DR, CD34 and CD56 expression in M(3); increased frequency of CD19 in M(2), CD14 and CD56 in M(5) and lack of MPO in M(0). In conclusion, multiparameter flow cytometry is a reliable technique in the diagnosis of AML, and some immunophenotypes correlate with FAB type.

[The application of sodium hyaluronate in joint diseases].

OBJECTIVE: To review the physiological function of sodium hyaluronate in joints and its clinical applications. METHODS: Many literatures were reviewed and analysed on therapeutic mechanism and the application foreground of sodium hyaluronate. RESULTS: Extrinsic sodium hyaluronate plays an important role in improving synovial fluid and protecting cartilages as well as suppressing inflammation, so it is used in the treatment of joint diseases such as knee osteoarthritis, rheumatoid arthritis or temporomandibular osteoarthritis. CONCLUSION: Sodium hyaluronate possesses a good applied prospect in joint diseases.

[Effect of peroxisome proliferator-activated receptors activators on plasminogen activator inhibitor-1 expression in HepG-2 cells].

AIM: To investigate the effect of different peroxisome proliferator-activated receptors (PPARs) activators on plasminogen activator inhibitor-1 in HepG-2 cell line and explore the effect of PPARs on PAL-1 gene expression. METHODS: Stearic acid, oleic acid, linoleic acid, fenofibrate, pioglitazone were used in the treatment of HepG-2 cell culture. The level of PAI-1 and PPARs mRNA was measured by reverse transcription-polymerase chain reaction (RT-PCR) and the level of PAI-1 activity and PPARs protein was determined by colorimetric assay and western blotting respectively. RESULTS: The mRNA and activity of PAI-1 significantly increased in the groups of oleic acid and linoleic acid compared with the control, but decreased in the group of fenofibrate. There were no significant changes in both groups of stearic acid and pioglitazone. The alterations in the level of PPARs mRNA and protein were not detected in all the treated groups compared with the control. CONCLUSION: Peroxisome proliferator-activated receptors activators play important roles in the PAI-1 gene expression and regulation. It is likely mediated by the activation of PPARalpha, but there might be other mechanisms.