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.

[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.

[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.

[ERK and JNK/AP-1 pathways involved in benzo(a)pyrene induced cell cycle changes in human embryo lung fibroblasts].

Objective: To study the role of mitogen activated protein kinase (MAPK)/activator protein-1 (AP-1) pathway in benzo(a)pyrene (B(a)P)-induced changes of cell cycle in human embryo lung fibroblasts (HELF).

Methods: AP-1 luciferase activity was determined by the Luciferase reporter gene assay using a luminometer. The expression levels and activity of extracellular signal-regulated protein kinase (ERK), c-Jun NH2-terminal kinase (JNK) and p38 were determined by Western blot.

[cyclin D1/E2F pathways involved in cell cycle changes of human embryo lung fibroblasts induced by benzo(a)pyrene].

Objective: To investigate the roles of cyclin D1/CDK4-E2F-1/4 pathway in cell cycle changes of human embryo lung fibroblasts (HELF) induced by two different benzo(a)pyrene [B(a)P] treatment models.

Methods: Two B(a)P treatment models: HELF were treated by 2 micromol/L B(a)P for 24 hours; HELF were treated by 100 micromol/L B(a)P three times 24 hours each and provide with some characteristics of transformed cells (T-HELF). Changes of cell cycle and the expression of cyclin D1, CDK4 and E2F-1/4 were checked using the flow cytometry and Western bolt analysis.

Role of cyclinD1 and CDK4 in the carcinogenesis induced by silica.

Objective: To study the role of cyclinD1 and CDK4 in malignant transformation of human fetal lung diploid fibroblast cell line (2BS) induced by silica.

Methods: Recombination vectors with sense and antisense pXJ41-cyclinD1 and pXJ41-CDK4 were constructed, and then transfected into the malignant transformed cells induced by silica, respectively. At the same time, pXJ41-neo was used as the control.

[Inhibition of the pathway of benzo (a) pyrene-induced cell cycle changes by all-trans retinoic acid in lung fibroblast].

Objective: To investigate the reverse effect of all-trans retinoic acid (ATRA) on Benzo (a) pyrene (B (a) P)-induced cyclin D1, CDK4, E2F-1 and E2F-4 expression and cell cycle progression in human embryo lung fibroblast (HELF).

Methods: After HELF cells was treated with ATRA, they were exposed to 2 micromol/L of B (a) P. Western blotting was employed to detect protein expression level; the RNA transfection techniques was used to investigate ATRA-induced signal pathway; flow cytometry was used to detect cell cycle progression.

[Role of cyclin D1 in carcinogenesis of human cells induced by quartz].

Objective: To study the role of cyclin D1 in malignant transformation of human embryonic lung diploid fibroblasts (HELF) induced by quartz.

Methods: pXJ41-cyclin D1 expressing sense and antisense cyclin D1 RNA were transinfected into malignant transformed HELF induced by quartz with DNA recombination and gene transduction. The expression of cyclin D1 was detected with hybridization in situ and immunohistochemistry methods to analyze changes in cell growth, double multiplication time, distribution of cell cycles, colony forming ability on soft agar, etc.

[The role of cycline dependent kinase 4 in the malignant transformation induced by silica].

Objective: To study the role of cycline dependent kinase 4 (CDK4) in the malignant transformation of human fetal lung diploid fibroblast cell (2BS) induced by silica.

Methods: Recombination vectors with antisense pXJ41-CDK4 were constructed, and then were transfected into the malignant transformed cells induced by silica. In situ hybridization and immunohistochemistry were used to analyze the expression of CDK4.

[Role of telomerase in chrysotile induced malignant transformation of normal human embryonic lung fibroblasts].

Objective: To explore the role of telomerase in asbestos dust induced malignant transformation of human embryonic lung fibroblasts in vitro.

Methods: Human telomerase catalytic subunit (hTERT) was transferred into human embryonic lung fibroblasts (HELF). Chrysotile dust at concentration of 2.

[Cloning of differentially displayed cDNAs involved in NaF-treated osteoblasts].

Objective: To explore the effects of excessive fluoride on the gene expression of rat osteoblasts.

Methods: Rat osteoblasts were treated with 2.0 mmol/L of sodium fluoride (NaF) for two weeks in vitro, and difference in the gene expression between the NaF-treated and normal osteoblasts was compared with mRNA differential display (DD-PCR) technique.

[Expression of type II collagen gene and structural change in bone tissues of rats with experimental fluorosis].

Objective: To investigate the effects of excessive intake of fluoride on the expression of type II collagen gene and types and morphological change of collagen fiber in the bone tissues of rats.

Methods: A rat model with fluorosis was established by adding 221 mg/L of sodium fluoride (NaF) to drinking water for the rats for 15 days, 30 days and two months, respectively. Type II collagen alpha1 (II) cDNA probe was prepared, and cDNA-mRNA in-situ hybridization was employed to detect change in expression of type II collagen mRNA in the bone tissues of rats with excessive intake of fluoride (221 mg/L NaF).