[The roles of activated protein-1 and cell cycle protein in silica-induced cell cycle changes].

Objective: To investigate the roles of cyclin D1 and CDK4 in the cell cycle changes of human embryonic lung fibroblasts (HELFs) exposed to silica.

Methods: HELFs were divided into 4 groups: control group, curcumin (20 µmol/L for 1 h) group, silica (200 µg/ml for 24 h) group and curcumin plus silica group, i.e.

[Silica induce cell cycle changes by mitogen-activated protein kinases pathway].

Objective: To investigate the roles of mitogen-activated protein kinases (MAPK) on silica-induced cell cycle changes.

Methods: After cells were treated with 200 microg/ml silica, Western blot and Immunofluorescence assays were utilized to detect the expression of cyclin D1, CDK4 and E2F-4, Flow cytometry was used to detect cell cycle progression, the dominant negative mutants techniques were used to investigate silica-induced signal pathway and the effects of which in silica-induced cell cycle changes.

Results: After cells were exposed to 200 microg/ml silica 24 h, the results of present study showed the proportion of cells in G1 phases was decreased.

[The roles of Ku80/p53 pathway in silica-induced cell cycle changes in human embryo lung fibroblasts].

Objective: To study the roles of Ku80/p53 pathway in silica-induced cell cycle changes in human embryo lung fibroblasts (HELF).

Methods: Ku80 siRNA expression vectors were transfected into HELF by lipofectamine. Flow cytometry was used to detect the distributions of cell cycle and western blot assay was used to determine the expression level of Ku80, p53 and p21 proteins or the phosphorylation levels of p53-ser15 after cells were exposed to silica.

[Roles of DNA dependent protein kinase in silica-induced cyclin E and CDK2 expressions and cell cycle changes in human embryo lung fibroblasts].

Objective: To study the roles of DNA dependent protein kinase (DNA-PK)in silica-induced cell cycle changes and expressions of CyclinE and CDK2 in human embryo lung fibroblasts (HELF).

Methods: The expressions of Ku80 and DNA-PKcs proteins were inhibited by siRNA plasmids, respectively. Flow cytometry was used to detect the distributions of cell cycle and western blot assay was used to determine the expression levels of CyclinE and CDK2 after cells were exposed to 200 microg/ml silica for 0, 3, 6, 12, 24 h.

[Role of p53 in silica-induced cell cycle alternation and DNA double-strand break repair in human embryo lung fibroblasts].

Objective: To study the role of p53 in silica-induced cell cycle alternation and DNA double strand breaks repair in human embryo lung fibroblasts (HELF).

Methods: Neutral comet assay was applied to detect silica-induced DNA double strand breaks. According to the neutral comet experimental result, the DNA repair competence was calculated.

[Roles of phosphatidylinositol 3 kinase in silica-induced DNA double strand breaks damage repair in human embryo lung fibroblasts].

Objective: To study the role of Phosphatidylinositol 3 kinase (PI3K) in silica-induced DNA double strand break repair in human embryo lung fibroblasts (HELF).

Methods: Control HELF cells and DN-Deltap85 (HELF transfected with Dominant negative mutant of PI3K) were treated with 200 microg/ml silica for different times. The expression levels of phosphor-H2AX (H2AX), Ku70, Ku80 and DNA-PKcs were determined by Western blot.

[Role of DNA-dependent protein kinase catalytic subunit in silica-induced DNA double-strand break repair in human embryo lung fibroblasts].

Objective: To study the role of DNA-dependent protein kinase catalytic subunit (DNA-PKcs) in silica-induced DNA double-strand break repair in human embryo lung fibroblasts (HELF).

Methods: Two stable transfectants, HELF transfected with DNA-PKcs siRNA (HELF-PKcs) and with negative control siRNA (HELF-NC), were established. HELF cells were treated with 0, 25, 50, 100, 200, 300 and 400 microg/ml silica for 12 h and with 200 microg/ml silica for different times (0, 1, 2, 6, 12 and 24 h).

[Decrease of cyclin D1 and CDK4 protein and their related factors induced by quartz in human embryonic lung fibroblasts].

Objective: To study the expression level of cyclin D1-CDK4 protein in human embryonic lung fibroblasts (HELF) induced by quartz, and to study whether the expression level of cyclin D1-CDK4 protein mediated by mitogen activated protein kinase (MAPK)/(AP-1) signaling pathways.

Methods: Cells were harvested after stimulation 2 h for the detection of cytokines. Cyclin D1 and CDK4 (cyclin dependent kinase 4) proteins was measured by immunocytochemistry (IC) and Western blot (WB).

Different patterns of cyclin D1/CDK4-E2F-1/4 pathways in human embryo lung fibroblasts treated by benzo[a]pyrene at different doses.

Objective: To investigate the roles of the cyclin D1/CDK4 and E2F-1/4 pathways and compare their work patterns in cell cycle changes induced by different doses of B[a]P.

Methods: Human embryo lung fibroblasts (HELFs) were treated with 2 micromol/L or 100 micromol/L B[a]P which were provided with some characteristics of transformed cells (T-HELFs). Cyclin D1, CDK4 and E2F-1/4 expressions were determined by Western blotting.

[Activated protein 1-cyclin D1/E2F 1 pathways involved in cell cycle changes induced by benzo (a) pyrene].

Objective: To investigate the roles of activated protein 1 (AP-1) in cell cycle changes on human embryo lung fibroblasts (HELF) induced by benzo (a) pyrene [B (a) P], and relationships between AP-1 and cyclin D1/CDK4-E2F-1/4.

Methods: Cells transfected with AP-1 luciferase reporter plasmid (AP-H) were cultured with serum-free RPMI1640 for 48 h, and treated with 2 micromol/L B (a) P for 24 h. AP-1 relative activity was detected by luciferase assay.

[ERK, JNK/AP-1 pathway was involved in silica-induced cell cycle changes].

Objective: To investigate the alteration of activator protein-1 (AP-1) luciferase activity in human embryo lung fibroblasts (HELF) after exposed to silica, and the role of mitogen activated protein kinase (MAPK)/AP-1 pathway on silica-induced cell cycle changes.

Methods: After HELF cells were treated with 200 microg/ml silica, immunofluorescence assays were employed to detect the translocation and the phosphorylation level of extracellular signal-regulated protein kinase (ERK) and c-Jun N-terminal kinase (JNK), flow cytometry was used to detect the distributions of cell cycle, the dominant negative mutant of ERK, JNK and p38 were applied to detect the upstream or downstream relationship of signaling pathways.

Results: After HELF-AP-1 cells were exposed to 200 microg/ml silica 6, 12, 24 h respectively, silica exposure lead to AP-1 activation in a time-dependent manner, inducing significant AP-1 activation at 6 h, reaching a maximum activation at 12 h, and having a little decrease at 24 h.

[Benzo (a) pyrene-induced human embryo lung cell cycle alterations through positive regulation of mitogen-activated protein kinase signal pathways].

Objective: To study the effects of benzo(a)pyrene (BaP) on the cell cycle distribution and activities of mitogen-activated protein kinase (MAPK) signal molecules (ERK1/2, JNK1/2 and p38) in human embryo lung cells (HELF), and to investigate the relationship between alterations of MAPK protein phosphorylation and the cell cycle distributions.

Methods: The phosphorylation of MAPK were induced by exposing HELF cells to BaP at 0.1, 0.

[c-Jun NH2-terminal kinase and extracellular signal-regulated protein kinase signaling pathways in regulation of benzo(a)pyrene-induced c-Jun activation in human embryo lung fibroblasts].

Objective: To investigate the role of mitogen activated protein kinases (MAPKs) signaling pathways in the regulation of benzo(a)pyrene (B(a)P)-induced c-Jun activation in human embryo lung fibroblasts (HELFs).

Methods: HELFs were cultured with 2.0 micromol/L B(a)P for various time (0, 3, 6, 12, 24 h) or with various concentration of B(a)P (0.

[The activation of MAPK/cyclin D1-CDK4 signaling pathway caused by quartz].

Objectives: To study the phosphorylation level of mitogen activated protein kinase (MAPK) in human embryonic lung fibroblasts (HELF), and the expression level of cyclin D1-CDK4 protein in S-HELF and whether the expression level of cyclin D1-CDK4 protein mediated by MAPK/AP-1 signaling pathway in S-HELF.

Methods: Two kinds of treatment: (1) Cells were harvested after stimulation 2 h for the detection of cytokines. (2) Cells were stimulated by quartz for a long time (2 months) for transformation characters (S-HELF).

Vitamin C inhibits benzo[a]pyrene-induced cell cycle changes partly via cyclin D1/E2F pathway in human embryo lung fibroblasts.

Objective: To study the molecular mechanism of the inhibitory effects of vitamin C on benzo[a]pyrene (B[a]P)-induced changes of cell cycle in human embryo lung fibroblast (HELF) cells.

Methods: The stable transfectants, HELF transfected with antisense cyclin D1 and antisense CDK4, were established. Cells were cultured and pretreated with vitamin C before stimulation with B[a]P for 24 h.

[Benzo(a)pyrene induced changes of cyclin D1, CDK4 and E2F-1/4 expression in human embryo lung fibroblasts].

Objective: To establish Benzo (a) pyrene-treated human embryo lung fibroblasts (HELF), which were provided with some characteristics of transformed cells (T-HELF), and observe the changes of cyclin D, CDK4 and E2F-1/4 expression in T-HELF cells.

Methods: Using 200, 100, 50, 25, 5 and 1 micromol/L B(a)P treated HELF cells for 24 h. Using MTT detected the cytotoxicity of B(a)P.

Benzo[a]pyrene-induced cell cycle progression is through ERKs/cyclin D1 pathway and requires the activation of JNKs and p38 mapk in human diploid lung fibroblasts.

Treatment of cells with carcinogen Benzo[a]pyrene (B[a]P) allows cells to evade G1 arrest and induces cells abnormal proliferation. However, the mechanisms of its action at cellular level are not well understood. To address this question, normal human embryo lung diploid fibroblasts (HELF) were selected in the present study.

[Vitamin C reverses benzo (a) pyrene-induced cell cycle changes by E2F pathway].

Objective: To study the role of E2F1/4 pathway in vitamin C reversing benzo (a) pyrene [B (a) P]-induced changes of cell cycle in human embryo lung fibroblasts (HELF) and the relationship between E2F1 and cyclin D1/CDK4.

Methods: The stable transfectants, HELF transfected with antisense cyclin D1 and antisense CDK4, were established to detect the relationship of signaling pathway. Cells were cultured and pretreated with vitamin C before stimulation with B (a) P for 24 hours.