Sarcophine-diol (SD), a structural modifications of
sarcophine, has shown chemopreventive effects on 7,12-dimethylbenz(a)anthracene-initiated and 12-O-tetradecanoylphorbol-13-acetate-promoted skin
tumor developments in mice.
Tumorigenesis is associated with uncontrolled cell growth and loss of apoptosis. In the present study, the effects of SD on cell growth and apoptosis in human
epidermoid carcinoma A431 cells were determined to assess whether SD could inhibit cell growth and/or induce apoptosis, thus elucidating possible mechanism of action. MTT assay was used for cell viability;
bromodeoxyuridine incorporation assay was used for cell proliferation; fluorescence-activated cell sorting analysis of
annexin V/
propidium iodide staining and TUNEL assay were used for determining apoptotic cells; Western blot analysis was used for determining the expression of
caspase-3 and colorimetric
caspase activity assays were used for determination of
caspase-3, -8, and -9 activity. The results showed that SD treatment at concentration of 200 to 600 microM resulted in a concentration-dependent decrease in cell viability and cell proliferation in A431 cells, which largely inhibited cell growth.
Sarcophine-diol treatment induced a strong apoptosis and significantly (P < .05) increased DNA fragmentation in A431 cells. Furthermore, SD treatment significantly (P < .05) increased the activity and expression of
caspase-3 through activation of upstream
caspase-8 in A431 cells rather than the activation of
caspase 9.
Sarcophine-diol treatment is relatively much less cytotoxic in monkey kidney normal
CV-1 cells. These results suggest that SD decreases cell growth and induces apoptosis through
caspase-dependent extrinsic pathway in A431 cells, and this may contribute to its overall chemopreventive effects in mouse
skin cancer models.