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The p53 tumor suppressor gene contributes to a series of life processes of cells. Previously, we have shown that T-17, a spirostanol saponin extracted from Tupistra chinensis induces cell cycle arrest, apoptosis and autophagy in gastric cancer cells. The p53 is essential in the cell cycle arrest induced by T-17, however, the effect of p53 on T-17-induced apoptosis and autophagy is still unclear. Here, our study shows that T-17 has no difference in the sensitivity of gastric cancer cells with different p53 status. By transfecting p53 siRNA into AGS cells (p53 wild type cells) or wild-type p53 into KATO-III cells (p53 deficiency cells), T-17 was found to induce apoptosis and autophagy in gastric cancer cells in a p53-independent manner. Pre-treatment with N-acetylcysteine (NAC, a ROS scavenger) demonstrated that reactive oxygen species (ROS) mediated T-17-induced p53-independent apoptosis. Besides, T-17 induces apoptosis and autophagy in gastric cancer cells by decreasing the expression of HMGB1, also in a p53-independent manner. But when we detected the inhibitory effect of T-17 on gastric cancer cell migration, it was found that p53 is essential. These experimental results showed that T-17 induced apoptosis and autophagy in gastric cancer cells in a p53-independent manner, but inhibited the migration of gastric cancer cells in a p53-dependent manner. Our research indicates that T-17 is a potential candidate for gastric cancer and provides support for better utilization of Tupistra chinensis.

Phytochemical investigations of the rhizome of Tupistra chinensis led to the isolation of ten new furostanol saponins along with fourteen known spirostanols. Their chemical structures were elucidated on the basis of spectroscopic and chemical methods, including IR, NMR, MS, and GC analyses. The antiproliferative effects against FaDu and Detroit 562 cell lines and inhibitory activities on nitric oxide (NO) production induced by lipopolysaccharide (LPS) in a macrophage cell line RAW 264.7 were assayed for all the isolated compounds. Compound 14 exhibited significant antiproliferative effects against FaDu and Detroit 562 cells with IC50 values of 1.1±0.1 and 1.2±0.1μM, respectively. Compounds 1, 2, 6, 13, 16, 19 and 24 exhibited inhibitory effects on NO production with IC50 values ranging from 15.7 to 46.2μM.

Phytochemical investigations of the rhizome of Tupistra chinensis led to the isolation of six new spirostanol saponins, one new spirostanol, along with eight known spirostanols. Their chemical structures were elucidated on the basis of spectroscopic and chemical methods, including IR, NMR, MS, and GC analyses. The antiproliferative effects against five human cancer cell lines were assayed for all the isolated compounds. Compounds 8, 12 and 15 showed potent cytotoxic activities against K562 cells. The isolated compounds were evaluated for their inhibitory activities on nitric oxide (NO) production induced by lipopolysaccharide in a macrophage cell line RAW 264.7. Compounds 2 and 12 showed significant inhibition on NO production with IC50 values of 16.1±1.8 and 13.5±1.2 μM, respectively.

Allium chinense, as a side dish on Asian table, is often used in folk medicine for its health benefits. (25R)-5α-spirostan-3β-yl-3-O-acetyl-O-β- d -glucopyranosyl-(1 → 2)-O-[β- d -glucopyranosyl-(1 → 3)]-O-β- d -glucopyranosyl-(1 → 4)-β- d -galactopyranoside (A-24) is a bioactive steroidal saponin isolated from Allium chinense. Previously, we have shown that A-24 has cytotoxic effects on cancer cells, but not on normal cells. To further explore the underlying mechanisms, in this study, we investigated the anticancer activity of A-24 in human gastric cancer cell lines in terms of cell proliferation, colony formation, cell cycle, induction of apoptosis/autophagy, and PI3K/Akt/mTOR pathway. A-24 showed dose-dependent cytotoxicity in SGC-7901 and AGS cell lines, it induced intrinsic mitochondrial pathway of apoptosis as well as autophagy, G2/M phase arrest and modulation of cyclinB1, p-cdc2, p-wee1 and p-Histone H3 expression. Furthermore, A-24 downregulated the phosphorylation of Akt at Ser473 and mTOR at Ser2448 in PI3K/Akt/mTOR pathway, and its downstream substrates p-p70S6K and p-4EBP1 in a dose-dependent manner. In addition, the pre-treatment of tumor cells with 3-methyladenine (3-MA) and LY294002 increased A-24-induced apoptosis. Collectively, these findings highlight the significance of downregulation of PI3K/Akt/mTOR pathway in A-24-induced apoptosis and autophagy, and the potential application of A-24 as a novel candidate in the treatment of human gastric adenocarcinoma.

Phytochemical investigations on the bulbs of Chinese onion led to the isolation of three new furostanol saponins (1, 2, 5) together with seven known furostanol saponins (3, 4, 6–10). Their chemical structures were elucidated on the basis of spectroscopic and chemical methods, including IR, MS, NMR, and GC analyses. The anti-proliferative and anti-inflammatory activities of the isolates were evaluated. Compounds 7–10 showed potential anti-proliferative activities against human cancer cell lines (HepG2, A549, SPC-A-1, MGC80-3, MDA-MB-231, SW620 and CNE-1) with IC50 values below 30 μM. Compounds 4 and 7 could induce G2/M cell-cycle arrest and apoptosis through mitochondria-mediate pathway in HepG2 cells. Compounds 7 and 10 showed strong inhibitory effects against LPS induced NO production in RAW264.7 cells with IC50 values of 2.01 ± 1.40 μM and 2.49 ± 1.54 μM, respectively.