The cell toxicity effect of secalonic acid D on GH3 cells and the related mechanisms.

To investigate the anti-pituitary adenoma effect of secalonic acid D (SAD) extracting from marine microorganisms, we used MTT colorimetric method to evaluate the proliferation of GH3 cells treated by SAD, the time- and dose-dependent effects and the value of IC50 were recorded. Hoechst staining, Tunel and flow cytometry methods were used to analyze the apoptosis rate of GH3 cells treated by SAD. Western blotting, RT-PCR and caspase inhibitor (Z-VAD-FMK) were used to investigate the possible mechanism of SAD induced apoptosis and the expression of growth hormone (GH). The results showed that SAD has a time- and dose-dependent effect on GH3 cells and the cytotoxic effect was mainly through apoptosis. The mechanisms were partly through the activity of caspase family and also G1/S phase block. In addition, SAD also can suppress the expression levels of growth hormone in GH3 cells, however, the RT-PCR results showed that the mechanism was not through changing the expression of GH mRNA. We concluded that SAD may be a potential anti-pituitary tumor drug and further in vivo studies should be performed.