Abstract: Objective: To investigate the effects of rhein on the proliferation, migration and invasion of the non-small cell lung cancer (NSCLC) A549 cells, and to elucidate the mechanisms. Methods: The NSCLC A549 cells were divided into control group and low, medium and high doses of rhein groups. The cells in each group were cultured for 24, 48 and 72 h in the culture medium without rheic and the culture medium containing 5, 10 and 20 μmol·L^-1 rhein. MTT method was used to analyze the proliferation rates of A549 cells in various groups. Flow cytometry was used to detect the apoptotic rates and the percentages of A549 cells at different cell cycles. Western blotting method was used to detect the expression levels of cysteine protease -3(Caspase-3), cysteine protease -9(Caspase-9), cytochrome C(Cyt-C) and apoptosis-induced factor (AIF) protines in the A549 cells in various groups. Scratch test and Transwell assay were used to detect the abilities of migration and invasion of A549 cells. Results: After treated with rhein for 24 h, compared with control group, the proliferation rates of the A549 cells in low, medium and high doeses of rhein groups were significantly decreased(P<0.05), the migration distances of cells were significantly reduced, and the number of invasion cells was significantly reduced; the apoptotic rates of the A519 cells in medium and high doses of rhein groups were significantly increased(P<0.05);the percentage of A519 cells in G₁ phase in high dose of rhein group was significantly reduced(P<0.05). After treated with rhein for 48 h, compared with control group, the expression levels of Caspase-3, Caspase-9, Cyt-C and AIF proteins in medium and high doses of rhein groups were significantly increased (P<0.05). Conclusion: Rhein can inhibit the proliferation, migration and invasion abilities of A549 cells and its mechanism may be related to increasing the expressions of Caspase-3, Caspase-9, Cyt-C and AIF proteins.

Key words: rhein, cancer, non-small cell lung, A59 cells, cell proliferation, cell migration, cell invasion