Proliferation, Apoptosis and Invasion effects of mistletoe alkali on human osteosarcoma U2OS in vitro

Extraction, physicochemical properties, bioactivities and application of natural sweeteners: A review

Natural sweeteners generally refer to a sweet chemical component directly extracted from nature or obtained through appropriate modifications, mainly secondary metabolites of plants. Compared to the first-generation sweeteners represented by sucrose and the second-generation sweeteners represented by sodium cyclamate, natural sweeteners usually have high sweetness, low-calorie content, good solubility, high stability, and rarely toxic side effects. Historically, researchers mainly focus on the function of natural sweeteners as substitutes for sugars in the food industry. This paper reviews the bioactivities of several typical natural sweeteners, including anti-cancer, anti-inflammatory, antioxidant, anti-bacterial, and anti-hyperglycemic activities. In addition, we have summarized the extraction, physicochemical properties, and application of natural sweeteners. The article aimed to comprehensively collate vital information about natural sweeteners and review the potentiality of tapping bioactive compounds from natural products. Hopefully, this review provides insights into the further development of natural sweeteners as therapeutic agents and functional foods.

Talaromides A-C, Bioactive Cyclic Heptapeptides from Talaromyces siglerae Isolated from a Marine Sponge

Three new cyclic heptapeptides, talaromides A-C (1-3), were isolated from cultures produced by the fungus Talaromyces siglerae (Ascomycota), isolated from an unidentified sponge. The structures, featuring an unusual proline-anthranilic moiety, were elucidated by analysis of spectroscopic data and chemical transformations, including the advanced Marfey's method and GITC derivatization. Talaromides A and B inhibited migration activity against PANC-1 human pancreatic cancer cells without significant cytotoxicity.

Bioactive Piperazic Acid-Bearing Cyclodepsipeptides, Lydiamycins E-H, from an Endophytic Streptomyces sp. Associated with Cinnamomum cassia

A chemical investigation of the endophytic Streptomyces sp. HBQ95, associated with the medicinal plant Cinnamomum cassia Presl, enabled the discovery of four new piperazic acid-bearing cyclodepsipeptides, lydiamycins E-H (1-4), and one known compound (lydiamycin A). Their chemical structures, including absolute configurations, were defined by a combination of spectroscopic analyses and multiple chemical manipulations. Lydiamycins F-H (2-4) and A (5) exhibited antimetastatic activity against PANC-1 human pancreatic cancer cells without significant cytotoxicity.

The Analysis of Differentially Expressed circRNAs Under the Antiproliferative Effect From 5-Fluorouracil on Osteosarcoma Cells

BACKGROUND

5-fluorouracil (5-FU) is a widely used drug for cancer treatment, but its effect and underlying mechanisms on osteosarcoma (OS) cells remain unclear.

METHODS

U2OS and MG63 cells were treated with 0, 50, 100, and 500 μM 5-FU. MTS and flow cytometry were used to examine the effect of 5-FU on cell viability and apoptosis, respectively. Circular RNA (circRNA) expression was detected using RNA sequencing and quantitative real-time PCR (qPCR). Differentially expressed circRNAs were further subjected to the Kyoto Encyclopedia of Genes and Genomes (KEGG) and gene ontology (GO) analysis to predict their functions. A circRNA-miRNA-mRNA interaction network was generated to analyze the regulatory networks of 5-FU-induced differentially expressed circRNAs. Western blotting (WB) was used to verify the protein in the downstream of circRNAs.

RESULTS

5-FU inhibited the cell viability of the MG63 cells in a concentration-dependent manner. The most significant effect was observed in the cells treated with 500 μM 5-FU. Apoptosis was also increased in the MG63 cells after 500 μM 5-FU treatment for 3 days. RNA sequencing results showed that 183 differentially expressed circRNAs (172 upregulated and 11 downregulated) in 5-FU-treated cells. KEGG and GO analysis showed that the differentially expressed circRNAs were primarily enriched in proliferation-, apoptosis-, and metabolism-related functions. qPCR was used to verify the most upregulated and downregulated circRNAs. The circRNA-miRNA-mRNA interaction network showed that these 8 circRNAs had a sizable regulatory network that links a series of genes involved in tumor suppression.

CONCLUSION

5-FU treatment resulted in the differentially expressed circRNAs that were proliferation- and apoptosis-associated and were involved in the 5-FU-induced inhibition of tumor proliferation in OS cells.

The natural sweetener metabolite steviol inhibits the proliferation of human osteosarcoma U2OS cell line

Steviol is the colonic metabolite of the natural sweetener steviol glycosides. It does not diffuse to the blood and the half maximal inhibitory concentration of steviol is longer compared with that of current chemotherapy agents, including 5-fluorouracil and doxorubicin. The present study demonstrated that steviol inhibits the proliferation of the human osteosarcoma U2OS cell line in a dose- and time-dependent manner, and that the inhibition rate is comparative with that of doxorubicin and 5-fluorouracil. The mechanism of this anticancer activity is also investigated. The results indicated that steviol inhibits U2OS cells through inducing G1 phase cell cycle arrest, downregulating the ability of colony formation via a mitochondrial apoptotic pathway, which was indicated by an increase of the Bax/Bcl-2 ratio and activation of cyclin-dependent kinase inhibitor 1, tumor protein 53 and cyclin-dependent kinase; whereas a Survivin and Caspase 3-independent mechanism was involved. Considering that steviol appears minimally in the plasma during metabolism, and possesses a median lethal dose of 100-fold greater compared with that of 5-fluorouracil, it may become a potential chemotherapy agent.