Functional Axis of PDE5/cGMP Mediates Timosaponin-AIII-Elicited Growth Suppression of Glioblastoma U87MG Cells.

Glioblastoma (GBM) is the most aggressive brain tumor, with high mortality. Timosaponin AIII (TIA), a steroidal saponin isolated from the medicinal plant Anemarrhena asphodeloides Bge., has been shown to possess anticancer properties in various cancer types. However, the effect of TIA on GBM is unknown. In this study, we reveal that TIA not only inhibited U87MG in vitro cell growth but also in vivo tumor development. Moreover, we found that the cause of TIA-induced cell growth suppression was apoptosis. When seeking to uncover antitumor mechanisms of TIA, we found that TIA diminished the expression of cGMP-specific phosphodiesterase 5(PDE5) while elevating the levels of guanylate cyclases (sGCß), cellular cGMP, and phosphorylation of VASPser239. Following the knockdown of PDE5, PDE5 inhibitor tadalafil and cGMP analog 8-Bro-cGMP both inhibited cell growth and inactivated ß-catenin; we reason that TIA elicited an antitumor effect by suppressing PDE5, leading to the activation of the cGMP signaling pathway, which, in turn, impeded ß-catenin expression. As ß-catenin is key for cell growth and survival in GBM, this study suggests that TIA elicits its anti-tumorigenic effect by interfering with ß-catenin function through the activation of a PDE5/cGMP functional axis.

[Inhibitory mechanisms of timosaponin Aâ ¢ on proliferation and growth of human glioblastoma cells].

To explore the inhibitory effect of timosaponin AⅢ on the proliferation of human glioblastoma cell line U87MG and investigate its related mechanism. As compared with the model group, the tumor weight was significantly reduced in timosaponin AⅢ-treated group. Timosaponin AⅢinhibited the proliferation of U87MG cell line in a dose-dependent manner. It up-regulated the gene and protein expression levels of p21, meanwhile inhibited the protein expression levels of ß-Catenin, Cyclin D1 and Bcl-2. It also inhibited the translocation of ß-Catenin into nucleus, suppressed the phosphorylation expression of ERK, but increased the phosphorylation expression of p38 and JNK. Combined use of JNK inhibitor SP600125 and p38 inhibitor SB203580 could decrease p21 and increase ß-Catenin protein expressions. Timosaponin AⅢ inhibited the proliferation of human glioblastoma cell line U87MG partly by intervening MAPK and Wnt/ß-Catenin signal pathways.

[Effects of four kinds of Chinese medicine monomer on growth of PANC-1 xenograft tumor and studying of molecular mechanism].

OBJECTIVE: The antitumor effects of icarisid II, timosaponin A-III, neferine and salidroside were studied in PANC-1 xenograft tumor. METHOD: To establish of the nude mice xenograft tumor model, PANC-1 cells were injected. When the tumor major diameter was reached 3-5 mm, the treatment was initiated. The mice were randomized into vehicle control and treatment groups of six animals per each. Chinese medicine monomer was injected intraperitoneally every day. In 23th day, mice were killed once a day, tumor tissue were isolated and weighed and divided into two parts. One part was fixed with formaldehyde for tissue section and immunohistochemistry, the another of tissue was frozen in liquid nitrogen then in - 80 degrees C refrigerator for gene and protein expression analysis. RESULT: In PANC-1 tumor xenograft experiment, compared with model group, timosaponin A-III (1.0 mg x kg (-1)) exerted significant inhibitory effects on tumor growth. Timosaponin A-III suppressed mRNA expressions of VEGF (P < 0.05), reduced protein expressions of VEGF (P < 0.05), activated Caspase-3 protein. Icarisid II, neferine and salidroside had not an excelled antitumor effect. CONCLUSION: Timosaponin A-III exerted an excelled antitumor effect. The antitumor mechanisms include anti-angiogenesis, apoptosis promotion.