Fucoxanthin Induces Ferroptosis in Cancer Cells via Downregulation of the Nrf2/HO-1/GPX4 Pathway.

This study investigated the mechanism by which fucoxanthin acts as a novel ferroptosis inducer to inhibit tongue cancer. The MTT assay was used to detect the inhibitory effects of fucoxanthin on SCC-25 human tongue squamous carcinoma cells. The levels of reactive oxygen species (ROS), mitochondrial membrane potential (MMP), glutathione (GSH), superoxide dismutase (SOD), malondialdehyde (MDA), and total iron were measured. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and Western blotting were used to assess glutathione peroxidase 4 (GPX4), nuclear factor erythroid 2-related factor 2 (Nrf2), Keap1, solute carrier family 7 member 11 (SLC7A11), transferrin receptor protein 1 (TFR1), p53, and heme oxygenase 1 (HO-1) expression. Molecular docking was performed to validate interactions. Compared with the control group, the activity of fucoxanthin-treated SCC-25 cells significantly decreased in a dose- and time-dependent manner. The levels of MMP, GSH, and SOD significantly decreased in fucoxanthin-treated SCC-25 cells; the levels of ROS, MDA, and total iron significantly increased. mRNA and protein expression levels of Keap1, GPX4, Nrf2, and HO-1 in fucoxanthin-treated cells were significantly decreased, whereas levels of TFR1 and p53 were significantly increased, in a concentration-dependent manner. Molecular docking analysis revealed that binding free energies of fucoxanthin with p53, SLC7A11, GPX4, Nrf2, Keap1, HO-1, and TFR1 were below -5 kcal/mol, primarily based on active site hydrogen bonding. Our findings suggest that fucoxanthin can induce ferroptosis in SCC-25 cells, highlighting its potential as a treatment for tongue cancer.

Transcriptomic profile of human erythroleukemia cells in response to Sargassum fusiforme polysaccharide and its structure analysis.

Sargassum fusiforme (S. fusiforme) has been used as an ingredient in Chinese herbal medicine for thousands of years. However, there are a limited number of studies concerning its therapeutic mechanism. High performance gel permeation chromatography (HPGPC) analysis showed that the average molecular weight of the S. fusiforme polysaccharide, SFPS 191212, is 43 kDa. SFPS 191212 is composed of mannose, rhamnose, galactose, xylose, glucose, and fucose (at a molar ratio: 2.1 : 2.9 : 1.8 : 15.5 : 4.6 : 62.5) with α- and ß-configurations. The present research evaluated the anti-tumor potential of the S. fusiforme polysaccharide in human erythroleukemia (HEL) cells in vitro. To explore the SFPS 191212's apoptosis mechanism in HEL cells, transcriptome analysis was performed on HEL cells that were incubated with SFPS 191212. The inhibitory effect of SFPS 191212 on HEL cell growth was also analyzed. It was found that SFPS 191212 inhibited HEL cell proliferation, reduced cell viability in a concentration-dependent manner, and induced an insignificant toxic effect on normal human embryonic lung (MRC-5) cells. Compared with the control group, transcriptome analysis identified a total of 598 differentially expressed genes (DEGs), including 243 up-regulated genes and 355 down-regulated genes. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed on all DEGs, and 900 GO terms and 52 pathways were found to be significantly enriched. Finally, 23 DEGs were randomly selected and confirmed by quantitative real-time polymerase chain reaction (qRT-PCR). Moreover, SFPS 191212 down-regulated the PI3K/Akt signal transduction pathway. Our results provide a framework for understanding the effect of SFPS 191212 on cancer cells and can serve as a resource for delineating the anti-tumor mechanisms of S. fusiforme.

Effect of Sargassum fusiforme polysaccharide on apoptosis and its possible mechanism in human erythroleukemia cells.

This study aimed to investigate the effects of Sargassum fusiforme polysaccharide (SFPS I, II, and III) on the apoptosis and regulation of human erythroleukemia (HEL) cells. The effect of different doses of SFPS on HEL cell growth was detected using the Cell Counting Kit-8 method, and apoptosis was detected by Hoechst staining. Cell cycle distribution and apoptosis were detected using flow cytometry. Expression of the cell cycle gene, p53, antiapoptotic genes, Bcl-xL and Bcl-2, and pro-apoptotic genes, Bax, Bad, and Caspase-3, as well as the expression of the corresponding proteins, were detected using real-time quantitative polymerase chain reaction (qPCR) and Western blot. The results showed that SFPS II and III decreased HEL cell viability and induced HEL cell apoptosis. Different concentrations of SFPS (I, II, and III) were detected that induced much less toxic effect in normal human embryonic lung (MRC-5) cells, and SFPS I increased cell proliferation, indicating its favorable selectivity towards cancer cells. The mechanism by which SFPS induced apoptosis was also found to be related to the induction of cell cycle arrest in the G0/G1 phase and the increased expression of apoptosis-related genes and proteins. We concluded that SFPS induces HEL cell apoptosis, possibly via activation of the Caspase pathway, providing the theoretical basis for the development of SFPS-based anti-tumor drug products.