Nitrofen suppresses cell proliferation and promotes mitochondria-mediated apoptosis in type II pneumocytes

作者：Tong Qiang song^*; Zheng Li duan; Tang Shao tao; Jiang Guo song; Ruan Qing lan; Zeng Fu qing; Dong Ji hua

来源：Acta Pharmacologica Sinica, 2007, 28(5): 672-684.

DOI：10.1111/j.1745-7254.2007.00552.x

• nitrofen
• pulmonary hypoplasia
• proliferating cell nuclear antigen
• apoptosis-inducing factor

Aim: To characterize the molecular mechanisms of nitrofen-induced pulmonary hypoplasia. Methods: After administration of nitrofen to cultured type IIA549 pneumocytes, cell proliferation and DNA synthesis were investigated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide colorimetry, colony formation assay, flow cytometry and [H-3]-thymidine incorporation assay. Apoptosis was measured by terminal transferase-mediated dUTP nick-end-labeling, acridine orange-ethidium bromide staining and flow cytometry. Expression of proliferating cell nuclear antigen (PCNA) and apoptosis-related genes was assayed by immunofluorescence, RT-PCR and Western blot. Results: Nitrofen inhibited the cell proliferation of A549 cells in a dose- and time-dependent manner, accompanied by downregulation of PCNA. As a result, the DNA synthesis of nitrofentreated A549 cells decreased, while cell cycle was arrested at G(0)/G(1) phase. Moreover, nitrofen induced apoptosis of A549 cells, which was not abolished by Z-Val-Ala-Asp(OCH3)- fluoromethylketone. In addition, nitrofen decreased the expression of Bcl-x(L), but not of Bcl-2, Bax, and Bak, resulting in a loss of mitochondrial membrane potential and the nuclear translocation of apoptosis-inducing factor (AIF). Meanwhile, nitrofen strongly activated the p38 mitogen-activated protein kinase (p38-MAPK). Pretreatment of cells with SB203580 (5 mu mol/L) blocked nitrofen-induced phosphorylation of p38-MAPK and abolished nitrofen-induced AIF translocation and apoptosis in A549 cells. Conclusion: Nitrofen suppresses the proliferation of cultured type II pneumocytes accompanied by the downregulation of PCNA, and induces mitochondria-mediated apoptosis involving the activation of p38-MAPK.

• 出版日期2007-5
• 单位华中科技大学