Background: Fucoidan is a fucose-enriched, sulfated polysaccharide found in brown algae; in recent years, this polysaccharide has been found to exert several biological effects, including antitumor effects, such as antiproliferation, activating apoptosis, and anti-angiogenesis of cancer cells. However, the antimetastatic effect of fucoidan and the related targeting receptors remain unknown. In the present study, we examined the inhibition of invadopodia formation and underlying mechanism of fucoidan on human liver cancer cells.Methods: We used 98% purified fucoidan from Sargassum species to treat the hepatocellular carcinoma (HCC) cells SMMC-7721, Huh7 and HCCLM3 in vitro and the HCCLM3 cell line in vivo. The HCC cells were cultured with various concentrations of Fucoidan-Sargassum (0-30 mg/mL). Migration, invasion and wound healing assays were performed to determine the antimetastatic effect of fucoidan on the HCC cells. Western blot analysis and immunofluorescence staining were conducted to determine the expression levels of invadopodia formation-regulating proteins and the targeting membrane receptor proteins.Results: Fucoidan-Sargassum inhibited the migration and invasion of HCC SMMC-7721, Huh7 and HCCLM3 cells in a dose-dependent manner. In the HCCLM3 cells, Fucoidan-Sargassum also decreased the expression levels of invadopodia-related proteins including Src, Cortactin, N-WASP, ARP3, CDC42, MMP2, MT1-MMP, and the targeting receptors integrin αV and β3 in a dose-dependent manner. Fucoidan-Sargassum also increased the levels of endoplasmic reticulum-related proteins, including GRP78, IRE1, SPARC, and the type IV collagen receptor proteins integrin α1 and β1. In vivo, Fucoidan-Sargassum reduced the size of liver tumors and decreased the number of lung metastatic foci in nude mice with hepatocellular carcinoma xenografts.Conclusion: These findings indicate that Fucoidan-Sargassum has an antimetastatic effect on SMMC-7721, Huh7 and HCCLM3 liver cancer cells, and the underlying mechanism involves targeting ITGαVβ3 and mediating the ITGαVβ3/SRC/E2F1 signaling pathway. These results suggest that Fucoidan-Sargassum may be a promising therapeutic antimetastatic compound in the development of a metastasis-preventive drug for treating liver cancer.

BackgroundColorectal cancer is one of the leading causes of death in China, and the development of effective drugs is urgently needed. Here, we report on Paeoniflorin (PF), a product isolated from the roots of the peony plant, as a possible candidate because of its anti-tumor effects on epithelial-to-mesenchymal transition (EMT) of PF in human colorectal cancer (CRC).Material/MethodsCell proliferation, wound healing, and Transwell assays were used to analyze the effects of PF on in vitro cell migration and invasion of HCT116 and SW480, 2 colorectal cancer cell lines. The tumor xenograft model was used to verify the anti-metastasis effects of PF in vivo. The RNA and protein levels of epithelia-cadherin (E-cadherin), Vimentin, and histone deacetylase2 (HDAC2) were measured by qPCR and Western blot analysis to explore the mechanism involved.ResultsOur results showed that PF inhibited colorectal cancer cell migration and invasion and suppressed the metastatic potential of the cancer cells in vivo. Moreover, PF significantly decreased the expression of HDAC2 and Vimentin, while increasing the expression of E-cadherin.ConclusionsThese results suggest that PF inhibits colorectal cancer cell migration and invasion ability and reverses the EMT process, through inhibiting the expression of HDAC2, and then affects the expression level of E-cadherin and Vimentin at the cell level. Our results were also verified in the tumor xenograft model. This indicates that PF may be a candidate for colorectal cancer treatment.

Genistein is a natural isoflavone with pharmacological or potentially anti-tumor properties. However, the resistance of cancer cells to genistein remains a major obstacle. This study focused on the mechanism implicated in the resistance of pancreatic cancer (PC) cells to genistein and the mechanism of action. First, key molecules and signaling pathways related to genistein resistance in PC cells were explored using bioinformatics tools. DEP domain containing MTOR interacting protein (DEPTOR), a typical inhibitor of the mammalian target of rapamycin (mTOR) signaling, was predicted to be poorly expressed in the genistein-resistant PC cells. Thereafter, genistein-resistant PC cells (Panc-1 and PaCa) were constructed. Altered expression of DEPTOR was introduced in cells, and everolimus (ELM), an mTOR-specific antagonist, was administrated in cells as well to examine their roles in genistein resistance. The cell apoptosis was examined in vitro and in vivo in mouse xenograft tumors. The upstream regulator of DEPTOR was predicted via bioinformatic tools. The bioinformatic analyses showed that the PI3K/AKT/mTOR signaling pathway was activated in the setting of DEPTOR downregulation in genistein-resistant PC cells. DEPTOR overexpression reduced the 50% inhibiting concentration (IC50) of genistein in PC cells and suppressed mTOR phosphorylation, and it increased caspase-3 activity, LDH release and apoptosis in PC cells. ELM treatment enhanced the sensitivity of PC cells to genistein in vitro and it strengthened the tumor-eliminating role of genistein in mice. ETS transcription factor ELK1 (ELK1), a transcription factor that negatively regulated DEPTOR transcription, was suppressed by genistein. Upregulation of ELK1 suppressed DEPTOR transcription and reduced the genistein sensitivity of cells, and it also blocked the genistein-sensitizing roles of ELM in PC cells. In conclusion, this study demonstrated that ELK1 reduces DEPTOR transcription, leading to mTOR phosphorylation and the drug resistance of PC cells.