Effects Of 4-HPR, ATRA On The Proliferation And Apoptosis Of A549 And The Mechanisms For Apoptosis

Objective To investigate the effects of 4-HPR,ATRA on adenocarcinoma of the human lung cell line A549 in vitro and the mechanisms for apoptosis. Method MTT was used to assess the antiproliferative effect of 4-HPR, ATRA on A549.Light microscope was used to observe morphologic changes. Hoechst 33258 was used to examine the nuclear changes. Flow cytometry was used to study the effects on cell cycle and apoptosis. Western blot was used to detect the protein expression on apoptosis. Results 4-HPR(1-10μmol/L) inhibited A549 effectively after a short time treatment, with a concentration-dependent manner. Under a light microscope, cells were decreased, turned small and round, lost theirs property of adherent growth. Compared with the normal cells, nuclear swelling, rounding and condensed staining were observed through a fluorescent microscope by Hoechst 33258. The percentages of cells at G0-G1 phase reduced noticeably. 4-HPR induced apoptosis with the decreased expression of Bcl-2,Bcl-xS/L and increased expression of Bax, Bak,without significant alteration of expression of Caspase-3, Caspase-9 and Erk1, Erk2. When the A549 cells were exposed to ATRA(1-10μmol/L), there were similar antiproliferative effects with 4-HPR in high concentration of the drug. However no effect was observed in low concentration. Conclusion 4-HPR could inhibit the proliferation of pulmonary adenocarcinoma cells remarkably, induce A549 apoptosis through changing family protein members expression of Bcl-2. It provides experimental evidence to further investigation in the mechanisms of 4-HPR and theoretical evidence for application of retinoic acid in pulmonary adenocarcinoma therapy.