DT-13 inhibited the proliferation of colorectal cancer via glycolytic metabolism and AMPK/mTOR signaling pathway.

Emerging hallmark of cancer is reprogrammed cellular metabolism, increased glycolytic metabolism is physiological characteristic of human malignant neoplasms. Saponin monomer 13 of the dwarf lilyturf tuber (DT-13) is the main steroidal saponin from Liriopes Radix, which has been reported to exert anti-inflammation and anti-tumor activities but low toxicity to normal tissue. However, the effect of DT-13 on metabolism process is still unclear. This study aims to characterize the role of DT-13 in glucose metabolism in colorectal cancer cells, and investigate whether the metabolism process is involved in the anti-cancer response of DT-13. Colony formation assay was employed to determine anti-proliferative effect induced by DT-13 at 2.5, 5, 10 μM. Apoptosis and cell cycle arrest were detected by Annexin V/PI staining and PI staining, respectively. Genetic inhibition of glycolytic metabolism was carried out by knockdown of GLUT1. Orthotopic implantation mouse model of colorectal cancer was used to assess in vivo antitumor effect of DT-13 (0.625, 1.25, 2.5 mg/kg). The chemoprevention effect of DT-13 (10mg/kg) was evaluated by using C57BL/6J APCmin mice model. Glycolytic-related key enzymes and AMPK pathway were detected by using quantitative real-time PCR, western blotting, and immunohistochemical staining. Our results showed that cell proliferation was significantly inhibited by DT-13 in a dose-dependent manner. DT-13 inhibited glucose uptake, ATP generation, and reduced lactate production. Furthermore, DT-13 remarkably inhibited GLUT1 expression in both mRNA and protein levels. Knocking down of GLUT1 led to reduced inhibition of glucose uptake after DT-13 treatment. Moreover, deletion of GLUT1 decreased inhibitory ratio of DT-13 on cancer growth. Orthotopic implantation mouse model of colorectal cancer further confirmed that DT-13 inhibited colorectal cancer growth via blocking GLUT1 in vivo. In addition, C57BL/6J APCmin mice model revealed that DT-13 dramatically reduced the total number of spontaneous adenomas in intestinal, which further confirmed the anti-tumor activity of DT-13 in colorectal cancer. Furthermore, the mechanistically investigation showed DT-13 activated AMPK and inhibited m-TOR to block cancer growth in vitro. DT-13 is a potent anticancer agent for colorectal cancer.

Wei X ，Mao T ，Li S ，He J ，Hou X ，Li H ，Zhan M ，Yang X ，Li R ，Xiao J ，Yuan S ，Sun L ... -  《-》

Licoricidin inhibits the growth of SW480 human colorectal adenocarcinoma cells in vitro and in vivo by inducing cycle arrest, apoptosis and autophagy.

Licorice (Glycyrrhiza uralensis Fisch.) possesses significant anti-cancer activities, but the active ingredients and underlying mechanisms have not been revealed. By screening the cytotoxic activities of 122 licorice compounds against SW480 human colorectal adenocarcinoma cells, we found that licoricidin (LCD) inhibited SW480 cell viability with an IC50 value of 7.2μM. Further studies indicated that LCD significantly induced G1/S cell cycle arrest and apoptosis in SW480 cells, accompanied by inhibition of cyclins/CDK1 expression and activation of caspase-dependent pro-apoptotic signaling. Meanwhile, LCD promoted autophagy in SW480 cells, and activated AMPK signaling and inhibited Akt/mTOR pathway. Overexpression of a dominant-negative AMPKα2 abolished LCD-induced inhibition of Akt/mTOR, autophagic and pro-apoptotic signaling pathways, and significantly reversed loss of cell viability, suggesting activation of AMPK is essential for the anti-cancer activity of LCD. In vivo anti-tumor experiments indicated that LCD (20mg/kg, i.p.) significantly inhibited the growth of SW480 xenografts in nude mice with an inhibitory rate of 43.5%. In addition, we obtained the glycosylated product LCDG by microbial transformation, and found that glycosylation slightly enhanced the in vivo anti-cancer activities of LCD. This study indicates that LCD could inhibit SW480 cells by inducing cycle arrest, apoptosis and autophagy, and is a potential chemopreventive or chemotherapeutic agent against colorectal cancer.

Ji S ，Tang S ，Li K ，Li Z ，Liang W ，Qiao X ，Wang Q ，Yu S ，Ye M ... -  《-》

Atractylenolide I inhibits colorectal cancer cell proliferation by affecting metabolism and stemness via AKT/mTOR signaling.

Atractylenolide I (ATL-1) is a natural herbal compound used in traditional Chinese medicine that has exhibited anti-cancer properties. The anti-tumorigenic activity of ATL-1 against colorectal cancer (CRC) and the underlying signaling pathways involved in its mechanisms are examined here. ATL-1 exerts therapeutic effect against CRC by disrupting glucose metabolism and cancer stem cell maintenance via AKT/mTOR pathway regulation. In vitro studies were performed in COLO205 and HCT116 CRC cell lines and in vivo studies were conducted in a mouse xenograft model of CRC tumor. CRC cells were treated with ATL-1 at various concentrations, with or without inhibitors of AKT or mTOR. Cell proliferation, apoptosis, invasion, stemness maintenance, glucose metabolism, and AKT/mTOR signaling were evaluated. CRC tumor-xenografted mice were treated with an AKT inhibitor and/or ATL-1, and glucose metabolism and stemness maintenance were examined in tumor tissues. ATL-1 significantly inhibited the invasion of CRC cells by inducing their apoptosis, possibly via the excessive production of reactive oxygen species. Glucose metabolism (Warburg effect) was also altered and stem-like traits were suppressed by ATL-1. In addition, ATL-1 effectively acted as an inhibitor or AKT/mTOR by downregulating the phosphorylation of proteins related to the AKT/mTOR pathway. In vivo studies showed that tumor weight and volume were reduced by ATL-1 and that aerobic glycolysis, stemness maintenance, and AKT/mTOR activation were impaired by ATL-1 in colorectal tumors. ATL-1 acts as an effective agent to suppress colorectal tumor progression, mainly by inhibiting CRC cell proliferation through altering apoptosis, glucose metabolism, and stem-like behavior. These processes were mediated by the AKT/mTOR signaling pathway both in vitro and in vivo. ATL-1 may be a potential agent to be used in molecular-targeted strategies for cancer treatment.

Wang K ，Huang W ，Sang X ，Wu X ，Shan Q ，Tang D ，Xu X ，Cao G ... -  《-》

Metabolic reprogramming and AMPKα1 pathway activation by caulerpin in colorectal cancer cells.

Yu H ，Zhang H ，Dong M ，Wu Z ，Shen Z ，Xie Y ，Kong Z ，Dai X ，Xu B ... -  《-》

DT-13, a saponin monomer of dwarf lilyturf tuber, induces autophagy and potentiates anti-cancer effect of nutrient deprivation.

Metabolic stress induces autophagy as a protective mechanism in tumorigenesis and development. Conversely, excessive autophagy in nutrient-deprived cancer cells would be beneficial for cancer therapy. DT-13, the saponin monomer 13 of the Dwarf lilyturf tuber, inhibited tumor metastasis and angiogenesis in previous studies. However, there is scarcity of data regarding the effect of DT-13 on autophagy process. Here, we demonstrated that DT-13 induced autophagy in human cancer cell lines and caused significant cell apoptosis under nutrient starvation. We firstly showed that DT-13 increased the accumulation of GFP-LC3 puncta and induced the expression of LC3-II in a dose- and time-dependent manner. DT-13 also upregulated the expression of Beclin-1, Atg-3 and Atg-7, and induced autophagic flux in human gastric cancer BGC-823 cells. We next found that low-toxic concentrations of DT-13 significantly induced apoptosis under nutrient deprivation. We finally demonstrated that the PI3K/Akt/mTOR signal pathway was involved in the cytotoxic effect of DT-13. Our data indicated that DT-13 was a novel autophagy inducer and might be considered in future treatment of cancer.

Li H ，Sun L ，de Carvalho EL ，Li X ，Lv X ，Khan GJ ，Semukunzi H ，Yuan S ，Lin S ... -  《-》