Melittin Inhibits Growth of Human Osteosarcoma 143B Cells through Induction of Apoptosis via Suppressing the Wnt/ß-catenin Signaling Pathway.

BACKGROUND AND PURPOSE: Osteosarcoma is the most commonly seen type of primary malignant bone tumors in children and adolescents. Partial patients with osteosarcoma cannot tolerate the side effects of chemotherapy drugs. Hence, it is urgent to find anti-osteosarcoma drugs with low side effects. Melittin is an anti-tumor Traditional Chinese Medicine with low side effects. The purpose of this study was to explore the anti-osteosarcoma effect of melittin and its possible molecular mechanisms. METHODS: The effects of melittin on cell growth were detected by CCK-8, clonal formation, and flow cytometry. The related molecules were also investigated by Real-time PCR and Western blot. A xenograft model in nude mice was established to observe the effects of melittin on tumor growth and the related molecular expression was detected by immunohistochemistry. RESULTS: Melittin can inhibit the proliferation of osteosarcoma 143B cells, reduce colony formation, and induce apoptosis while significantly up-regulating the expression of Bax and Caspase-3 and down-regulating the expression of Bcl-2 proteins. Moreover, treatment with melittin significantly reduced the mRNA and protein levels of ß-catenin and Wnt/ß- catenin related genes (LRP5, c-Myc, and Survivin) in osteosarcoma 143B cells in vitro. The xenograft model found that melittin significantly inhibited tumor growth and decreased the protein expression levels of ß-catenin and Wnt/ß- catenin related genes in vivo. CONCLUSION: These findings show that melittin could inhibit the growth of osteosarcoma 143B cells, which may be related to the inhibition of Wnt/ß-catenin signaling pathway activity and induce apoptosis by up-regulating the ratio of Bax/Bcl-2 in osteosarcoma 143B cells. Therefore, melittin is a promising anti-tumor drug for the treatment of osteosarcoma.

Highly enriched exosomal lncRNA OIP5-AS1 regulates osteosarcoma tumor angiogenesis and autophagy through miR-153 and ATG5.

OBJECTIVE: This study aims to investigate the regulatory role of exosome lncRNA OIP5-AS1 in tumor progression and autophagy. METHODS: Seventy-three cases of osteosarcoma (OS) tissues and 56 cases of adjacent normal tissues were collected to culture human OS cell line HOS. The exosomes secreted by OS cell line were isolated and collected. Apoptosis and exosome markers were detected by flow cytometry. A nude mouse model of OS was established. The gene expression levels of lncRNA OIP5-AS1, miR-153 and autophagy-related protein 5 (ATG5) were quantified by real-time quantitative PCR (RT-PCR). The binding sites of lncRNA OIP5-AS1 and miR-153 were predicted by Starbase3.0, and the binding sites of miR-153 and ATG5 were predicted by Targetscan7.2. The gene binding sites were verified by luciferase reporter gene detection or RNA immunoprecipitation (RIP). The relative level of protein was tested by Western blot. Transwell was applied to test migration and invasion of OS cells. The angiogenesis of OS cells was tested by tubule formation test. RESULTS: The results of RT-PCR showed that lncRNA OIP5-AS1 levels were elevated in OS cells and exosomes secreted by cells. Cell function experiments revealed that the proliferation, migration, and invasion of OS cells were promoted by exosomal lncRNA OIP5-AS1. In exosomes, lncRNA OIP5-AS1 inhibited the expression of LC3-II and Beclin 1 proteins, indicating that exosomal lncRNA OIP5-AS1 inhibited autophagy. According to the results of bioinformatics tools and dual-luciferase reporter (DLR) assay or RNA immunoprecipitation (RIP), miR-153 targeted the 3'-UTR of lncRNA OIP5-AS1 and autophagy-related protein 5 (ATG5). The results of western blot (WB) assay showed that exosomal lncRNA OIP5-AS1 and down-regulated miR-153 led to the enhancement of ATG5 protein expression, while up-regulated miR-153 resulted in the decrease of ATG5 protein expression. ATG5 was negatively correlated with miR-153 and positively correlated with lncRNA OIP5-AS1. The results of tubule formation assay disclosed an increase in the angiogenesis level caused by the exosomal lncRNA OIP5-AS1, which was then reversed by the increase of miR-153 and decrease of ATG5. CONCLUSION: Highly enriched exosomal lncRNA OIP5-AS1 can regulate OS tumor angiogenesis and autophagy through miR-153 and ATG5.

Anticancer effects of deproteinized asparagus polysaccharide on hepatocellular carcinoma in vitro and in vivo.

Hepatocellular carcinoma (HCC) is one of the most aggressive malignancies in the world whose chemoprevention became increasingly important in HCC treatment. Although the anticancer effects of asparagus constituents have been investigated in several cancers, its effects on hepatocellular carcinoma have not been fully studied. In this study, we investigated the anticancer effects of the deproteinized asparagus polysaccharide on the hepatocellular carcinoma cells using the in vitro and in vivo experimental model. Our data showed that deproteinized asparagus polysaccharide might act as an effective inhibitor on cell growth in vitro and in vivo and exert potent selective cytotoxicity against human hepatocellular carcinoma Hep3B and HepG2 cells. Further study showed that it could potently induce cell apoptosis and G2/M cell cycle arrest in the more sensitive Hep3B and HepG2 cell lines. Moreover, deproteinized asparagus polysaccharide potentiated the effects of mitomycin both in vitro and in vivo. Mechanistic studies revealed that deproteinized asparagus polysaccharide might exert its activity through an apoptosis-associated pathway by modulating the expression of Bax, Bcl-2, and caspase-3. In conclusion, deproteinized asparagus polysaccharide exhibited significant anticancer activity against hepatocellular carcinoma cells and could sensitize the tumoricidal effects of mitomycin, indicating that it is a potential therapeutic agent (or chemosensitizer) for liver cancer therapy.

Asparagus polysaccharide and gum with hepatic artery embolization induces tumor growth and inhibits angiogenesis in an orthotopic hepatocellular carcinoma model.

Liver cancer is one of leading digestive malignancies with high morbidity and mortality. There is an urgent need for the development of novel therapies for this deadly disease. It has been proven that asparagus polysaccharide, one of the most active derivates from the traditional medicine asparagus, possesses notable antitumor properties. However, little is known about the efficacy of asparagus polysaccharide as an adjuvant for liver cancer chemotherapy. Herein, we reported that asparagus polysaccharide and its embolic agent form, asparagus gum, significantly inhibited liver tumor growth with transcatheter arterial chemoembolization (TACE) therapy in an orthotopic hepatocellular carcinoma (HCC) tumor model, while significantly inhibiting angiogenesis and promoting tumor cell apoptosis. Moreover, asparagine gelatinous possessed immunomodulatory functions and showed little toxicity to the host. These results highlight the chemotherapeutic potential of asparagus polysaccharide and warrant a future focus on development as novel chemotherapeutic agent for liver cancer TACE therapy.