| Summary: | 碩士 === 中山醫學大學 === 醫學檢驗暨生物技術學系碩士班 === 102 === Gossypetin, a flavone originally isolated from Hibiscus and Gossypium species, has been shown to possess antioxidant, antimicrobial, and anti-atherosclerotic activities. However, the molecular mechanisms involved in chemopreventive activity of gossypetin are poorly understood. In this study we were conducted to examine the mechanism of the anti-cancer potential of gossypetin. We utilized the well-established in vitro and in vivo methods, trypan blue assay, flow cytometric analysis, 4'',6-diamidino-2-phenylindole (DAPI) assay, acidic vesicular organelles (AVO) stain and a mouse model, to analyze the effect of gossypetin on cell viability, cell cycle, and programmed cell death of human prostate cancer (CaP) cells, incluging LNCaP, PC3, and DU145 cells. To highlight the anti-cancer mechanisms of gossypetin, the expressions of molecular proteins were measured by Western blotting. Gossypetin could inhibit LNCaP, PC3, and DU145 cell growth in a dose-dependent manner. Gossypetin also was evaluated for apoptotic activities in CaP cells. Our results revealed that the three kinds of cells CaP cells showed the different morphology. LNCaP and PC3 cells presented DAPI-positive morphology, and had an increase in autophagosomes with double-membrane structure after a 24-h treatment with gossypetin. The growth inhibitory effect of gossypetin on DU145 cells only was mediated via apoptotic mechanism. Furthermore, this apoptotic effect of gossypetin in LNCaP cells might be mediated via the regulation of Bcl-2 family and inhibition of class I PI3K/Akt/mTOR pathway. In addition, gossypetin mainly could induce cellular autophagy via class III PI3K/Beclin 1/Atg-5/12/LC3 signaling. Finally, gossypetin was evidenced by its inhibition on the growth of LNCaP cells in xenograft tumor studies. As a result, our data presented the first evidence of gossypetin as an inducer of progressed cell death in LNCaP cells via dual apoptotic and autophagic pathways. These findings may open interesting perspectives to the strategy in human CaP treatment.
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