Previously, we found that 3,4-(methylenedioxy)-1-(2',3'-epoxypropyl)-benzene (
safrole oxide) induced a typical apoptosis in A549 human
lung cancer cells by activating
caspase-3, -8, and -9. In this study, we further investigated which upstream pathways were activated by
safrole oxide during the apoptosis. Immunofluorescence assay combined with
laser scanning confocal microscopy revealed that both Fas and
Fas ligand (FasL) were up-regulated by the small molecule. In addition, Fas
protein distribution was altered, showing a clustering distribution instead of a homogeneous one. Subsequently, Western blot analysis confirmed the up-regulations of Fas and its membrane-binding form of FasL (m-FasL), as well as P53
protein. Conversely,
safrole oxide hardly affected
integrin beta4 subunit expression or distribution, which was reflected from the data obtained by immunofluorescence assay combined with
laser scanning confocal microscopy. The results suggested that Fas/FasL pathway might be involved in
safrole oxide-induced apoptosis of A549 cells, while
integrin beta4 might be irrelevant to the apoptosis. Nevertheless, we first found the strong expression of
integrin beta4 in A549 cells. The study first suggested that
safrole oxide might be used as a small molecular promoter of Fas/FasL pathway to elicit apoptosis in A549 cells, which would lay the foundation for us to insight into the new strategies for
lung cancer therapy.