Objective: To investigate the effects of jolkinolide B on proliferation of MDA-MB-231 cells and cell cycles in human breast cancer. Method: MDA-MB-231 cells in logarithmic phase were selected and added with jolkinolide B

to achieve the final concentrations of 0

2.5

5

10

20

40

80 mg·L-1. MTT method was used to measure the growth inhibitory rate of jolkinolide B on MDA-MB-231 cells. For 10

20

40

80 mg·L-1groups

the effect of jolkinolide B on cell cycle of MDA-MB-231 cells was assayed by flow cytometer. The mRNA and protein expression levels of eukaryocytic translation initiation factor 4E (eIF4E) or CyclinD1 were detected by RT-PCR and Western blot assay. Result: With the increase of concentrations of jolkinolide B

it could significantly inhibit the proliferation of MDA-MB-231 cells and block the cells at G1 phase. Compared with the blank group

20

40 μmol·L-1 jolkinolide B could inhibit mRNA expressions of CyclinD1 and eIF4E

and inhibit the mRNA and protein expressions of CyclinD1 in transfected eIF4E-siRNA group

and meanwhile

the cell cycle was blocked in G1 phase. Conclusion: The jolkinolide B could block the cell cycle in G1 phase by down-regulating the expression of eIF4E and CyclinD1.