Dust ; Humans ; Pneumoconiosis ; etiology

Animals ; Antigens, Nuclear ; DNA ; genetics ; metabolism ; DNA Breaks, Double-Stranded ; DNA Repair ; DNA-Binding Proteins ; Humans ; Ku Autoantigen

Animals ; DNA Damage ; DNA Repair ; DNA-Activated Protein Kinase ; Humans

Genomics ; Proteomics ; Toxicology

Apoptosis ; Cell Cycle ; Cell Differentiation ; Cell Proliferation ; Humans ; Neoplastic Processes ; Proto-Oncogene Proteins c-jun ; genetics ; metabolism ; physiology

Attitude to Health ; China ; Dust ; prevention & control ; Humans ; Needs Assessment ; Occupational Exposure ; prevention & control ; Occupational Health Services ; Pneumoconiosis ; prevention & control ; Surveys and Questionnaires

Dust ; Humans ; Occupational Exposure ; prevention & control ; Pneumoconiosis ; prevention & control

China ; epidemiology ; Dust ; prevention & control ; Humans ; Silicon Dioxide ; chemistry ; Silicosis ; epidemiology ; prevention & control

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

METHODSHELFs 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. after exposure to 20 µmol/L curcumin for 1h, the HELFs were treated with 200 µg/ml silica for 24 h. Western blot and Immunofluorescence assays were utilized to detect the expression levels of cyclin D1, CDK4 and E2F1/4. Flow cytometry was used to detect the cell cycle progression, the RNA transfection technique was used to investigate the silica-induced signal pathway and the roles of which in silica-induced cell cycle changes.

RESULTSThe expression levels of cyclin D1 and CDK4 significantly increased and the expression level of E2F-4 decreased obviously, but the expression level of E2F-1 did not significantly change in silica group. The proportion of G1 phase cells obviously decreased and the proportion of S phase cells significantly increased in silica group, as compared with control group (P < 0.05). When suppressing the expression of cyclin D1 or CDK4, the proportions of cells in G1 phase in anti-D1 plus silica group and anti-K4 plus silica group did not obviously change, as compared with control group. When suppressing AP-1 activity, the cyclin D1 and CDK4 expression levels decreased and the E2F-4 expression level increased in curcumin plus silica group, as compared with silica group.

CONCLUSIONThe results of present suggested that 200 µg/ml silica could induce the high expression of cyclin D1 and CDK4 and the low expression of E2F-4, resulting in the cell cycle changes by AP-1/cyclin D1 pathway in HELFs.

Cell Cycle ; drug effects ; Cells, Cultured ; Cyclin D1 ; metabolism ; Cyclin-Dependent Kinase 4 ; metabolism ; E2F4 Transcription Factor ; metabolism ; Fibroblasts ; cytology ; metabolism ; G1 Phase ; Humans ; Quartz ; adverse effects ; Transcription Factor AP-1 ; metabolism ; Transfection

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

METHODSAfter 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.

RESULTSAfter 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. Silica-induced cell cycle alternation was markedly impaired by stable expression of a dominant negative mutants of ERK or JNK, but not p38. It was found that ERK and JNK were involved in silica-induced cyclin D1 and CDK4 overexpression and the decreased expression of E2F-4.

CONCLUSIONERK and JNK, but not p38, mediated silica-induced cell cycle changes in human embryo lung fibroblasts.

Cell Cycle ; drug effects ; Cell Division ; drug effects ; Cells, Cultured ; Fibroblasts ; cytology ; drug effects ; pathology ; Humans ; MAP Kinase Signaling System ; drug effects ; Mitogen-Activated Protein Kinases ; metabolism ; Quartz ; toxicity