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.

Polysaccharide extracted from the Sargassum fusiforme induces cell cycle arrest and apoptosis of B16F10 melanoma cells through the PI3K/AKT pathway.

BACKGROUND: SARGASSUM FUSIFORME: (S. fusiforme) is a brown alga that has been utilized as a medicine for a long time. Polysaccharides extracted from S. fusiforme demonstrate antitumor activities. METHODS: The impact of S. fusiforme polysaccharides (SFPS 191,212) on the proliferation, apoptosis, and cell cycle kinetics of B16F10 murine melanoma cells were thoroughly investigated in this work. The anticancer activities of the SFPS 191,212 compounds were assayed in the B16F10 cells at both transcriptional and translational levels. RESULTS: The compound exhibited concentration-dependent effects. Moreover, SPFS 191,212 increased the numbers of apoptotic cells and arrested the cell cycle in the S phase of the quantitative real-time PCR. From western blotting, it was verified that the SFPS 191,212 treatment improved the expression of Bax, Caspase-9, and Caspase-3 genes and proteins, while it reduced phosphatidylinositol 3 kinase and Bcl-2 genes and proteins, suggesting the involvement of mitochondria. CONCLUSION: Overall, SFPS 191,212 can be further explored as a potential functional food or adjuvant agent for the prevention or treatment of melanoma.

Anti-Leukemia Activity of Polysaccharide from Sargassum fusiforme via the PI3K/AKT/BAD Pathway In Vivo and In Vitro.

Studies have shown that Sargassum fusiforme and its extracts are effective herbal treatments for leukemia. We previously found that a polysaccharide from Sargassum fusiforme, SFP 2205, stimulated apoptosis in human erythroleukemia (HEL) cells. However, the structural characterization and antitumoral mechanisms of SFP 2205 remain uncertain. Here, we studied the structural characteristics and anticancer mechanisms of SFP 2205 in HEL cells and a xenograft mouse model. The results demonstrated that SFP 2205, with a molecular weight of 41.85 kDa, consists of mannose, rhamnose, galactose, xylose, glucose, and fucose with monosaccharides composition of 14.2%, 9.4%, 11.8%, 13.7%, 11.0%, and 38.3%, respectively. On animal assays, SFP 2205 significantly inhibited growth of HEL tumor xenografts with no discernible toxicity to normal tissues. Western blotting showed that SFP 2205 therapy improved Bad, Caspase-9, and Caspase-3 protein expression, and ultimately induced HEL tumor apoptosis, indicating mitochondrial pathway involvement. Furthermore, SFP 2205 blocked the PI3K/AKT signaling pathway and 740 Y-P, an activator of the PI3K/AKT pathway, rescued the effects of SFP 2205 on HEL cell proliferation and apoptosis. Overall, SFP 2205 may be a potential functional food additive or adjuvant for preventing or treating leukemia.

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.