Influence of protein kinase C signal pathways on the expressi on of cell cycle-regulating protein in chrysotile induced proliferation of h uman embryonic pulmonary fibroblasts

Abstract

Objective To study the relation of cell cycle-regulating protein expression with up-stream protein kinase C(PKC) signa l transduction pathways and the effect of PKC chrysotile-induced proliferation of human embryonic pulmonary fibroblast(HEPF). Methods Flow cytometry to measure the expression of cell cycle-regulating protein of HEPF mediated by chrysotile in vitro was used,and positive control(SiO2),nega tive control(TiO2),normal control(rabbit alveolar macrophage,AM) and blank con trol were set up. Results In chrysotile group,the p ositive expression rate of Cyclin D1,Cyclin E,PCNA and Cyclin A was 19.0%,22.8 %,79.7% and 65.1% respectively,significantly lower than that of the differ ent controls(P<0.05),the positive expression rate of Cyclin D1 and Cyclin E was significantly lower than that of PCNA and Cyclin A(P<0.01).But the pos itive expression rate of p34cdc2 kinase and Cyclin B1 was higher than that of B.control and AM group. When PKC signal pathway was inhibited by PKC inhibitor,t he positive expression rate of PCNA significantly decreased(P<0.05) in chrys otile group,and the change in positive expression rate of p34cdc2 kinase was not obvious.Conclusion These cell cycle-regulating proteins may be involved in chrysotile-induced proliferation of HEPF.The changes of PCNA expression may relate to the up-stream PKC signal pathway.