Antitumor Activity of Spicatoside A by Modulation of Autophagy and Apoptosis in Human Colorectal Cancer Cells

详细信息    查看全文

• 作者：Won Kyung Kim ; Yuna Pyee ; Hwa-Jin Chung ; Hyen Joo Park ; Ji-Young Hong ; Kun Ho Son ; Sang Kook Lee
• 刊名：Journal of Natural Products
• 出版年：2016
• 出版时间：April 22, 2016
• 年：2016
• 卷：79
• 期：4
• 页码：1097-1104
• 全文大小：531K
• 年卷期：0
• ISSN：1520-6025

文摘

The antitumor activity of spicatoside A (1), a steroidal saponin isolated from the tuber of Liriope platyphylla, and its underlying mechanisms were investigated in HCT116 human colorectal cancer cells. Compound 1 induced autophagy and apoptotic cell death and inhibited tumor growth in a nude mouse xenograft model implanted with HCT116 cells. Treatment with 1 for 24 h enhanced the formation of acidic vesicular organelles in the cytoplasm, indicating the induction of the onset of autophagy. This event was associated with the regulation of autophagic markers including microtubule-associated protein 1 light chain 3 (LC3)-II, p62, beclin 1, lysosomal-associated membrane protein 1 (LAMP 1), and cathepsin D by inhibiting the PI3K/Akt/mTOR signaling pathway, regulating mitogen-activated protein kinase (MAPK) signaling, and increasing p53 levels. However, a prolonged exposure to 1 resulted in apoptosis characterized by the accumulation of a sub-G1 cell population and an annexin V/propidium iodide (PI)-positive cell population. Apoptosis induced by 1 was associated with the regulation of apoptotic proteins including Bcl-2, Bax, and Bid, the release of cytochrome c into the cytosol, and the accumulation of cleaved poly-ADP-ribose polymerase (PARP). Further study revealed that cleavage of beclin 1 by caspases plays a critical role in the 1-mediated switch from autophagy to apoptosis. Taken together, these findings highlight the significance of 1 in the modulation of crosstalk between autophagy and apoptosis, as well as the potential use of 1 as a novel candidate in the treatment of human colorectal cancer cells.