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Proanthocyanidins are flavonoids that are widely present in the skin and seeds of various plants, with the highest content in grape seeds. Many experiments have shown that proanthocyanidins have antitumor activity both in vivo and in vitro. Autophagy and apoptosis of tumor cells induced by drugs are two of the major causes of tumor cell death. However, reports on the effect of autophagy induced by drugs in tumor cells are not consistent and suggest that autophagy can have synergistic or antagonistic effects with apoptosis. This research was aimed at investigating whether proanthocyanidins induced autophagy and apoptosis in human gastric cancer cell line MGC-803 cells and to identify the mechanism of proanthocyanidins action to further determine the effect of proanthocyanidins-induced autophagy on apoptosis. MTT assay was used to examine the proanthocyanidin cytotoxicity against human gastric cancer cell line MGC-803. Transmission electron microscopy and monodansylcadaverine (MDC) staining were used to detect autophagy. Annexin V APC/7-AAD double staining and Hoechst 33342/propidium iodide (PI) double staining were used to explore apoptosis. Western blotting was used to determine expression of proteins related to autophagy and apoptosis. Real-time quantitative PCR technology was used to determine the mRNA level of Beclin1 and BCL-2. The results showed that proanthocyanidins exhibit a significant inhibitory effect on the human gastric cancer cell line MGC-803 proliferation in vitro and simultaneously activate autophagy and apoptosis to promote cell death. Furthermore, when proanthocyanidin-induced autophagy is inhibited, apoptosis increases significantly, proanthocyanidins can be used together with autophagy inhibitors to enhance cytotoxicity.

Astragaloside IV is the main ingredient of the medicinal herb Radix astragali, which has reported to have antitumor activity in vitro and in vivo. To determine whether the inhibitory effect of astragaloside IV on the invasion and metastasis of the cervical cancer cells is associated with epithelial-mesenchymal transition (EMT), wound healing and Transwell assays were performed using SiHa cervical cancer cells and demonstrated that astragaloside IV inhibited invasion and migration of human SiHa cervical cancer cells in vitro. Immunocytochemical and western blot analyses indicated that astragaloside IV inhibited EMT by affecting the expression of transforming growth factor-β1 (TGF-β1) and E-cadherin in the cancer cells. Two Smad-independent pathways mediated by TGF-β1 were identified to be associated with the effects of astragaloside IV, namely, mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3 kinase (PI3K) signaling pathways. The data indicated that astragaloside IV has inhibitory effects on phosphorylation of P38 MAPK, PI3K, AKT and mTOR of SiHa cells of cervical cancer. Furthermore, MAPK and PI3K pathway inhibitors were administered to the cancer cells and the expression of E-cadherin, a marker of EMT, was determined by reverse transcription-quantitative polymerase chain reaction. The results demonstrated that MAPK and PI3K pathways were involved in the inhibitory effect of astragaloside IV on EMT. In vivo small animal imaging techniques was performed and demonstrated that astragaloside IV inhibited the metastasis of cervical cancer cells. Taken together, the findings demonstrated that astragaloside IV inhibits the invasion and migration of cervical cancer cells in vitro and in vivo.

Diosgenin is an important basic raw material for the production of steroid hormone drugs. It can be isolated and purified from a variety of traditional Chinese medicines or plants. Modern molecular biological studies have shown that diosgenin inhibits various tumor cells migration and invasion ability to varying degrees in vitro and in vivo. The aim of the present study was to observe the inhibitory effects of diosgenin on the invasive and metastatic capabilities of osteosarcoma cells and to determine the association between the effects of diosgenin on the epithelial-mesenchymal transition (EMT). Wound healing and Transwell assays were used to observe the inhibitory effects of diosgenin on the invasion and migration of two osteosarcoma cell lines. Immunofluorescence was used to observe changes in transforming growth factor β1 (TGF-β1) protein expression levels in the osteosarcoma cells following drug administration. EMT-associated proteins, including TGFβ1, E-cadherin and vimentin were detected by western blotting, which demonstrated that the drug may inhibit the initiation of EMT in osteosarcoma cells. Western blot analysis of the expression of all the proteins in the mitogen-activated protein kinase (MAPK) pathway demonstrated that the drug inhibited the MAPK signaling pathway. The primary mechanism of action of diosgenin was the inhibition of the phosphorylated p38 (pP38) protein. Through a combination of inhibitors of the p38MAPK signaling pathway and detection of the downstream EMT marker protein E-cadherin by quantitative PCR, pP38 was confirmed to be a target of diosgenin in the inhibition of EMT in the osteosarcoma cells via the MAPK molecular signaling pathway. Diosgenin may exhibit utility as an auxiliary drug for the clinical reduction of metastasis in patients with osteosarcoma.