This study aimed to explore the role of lactoferrin (LTF) in atherosclerosis (AS) and its possible mechanisms. Human left coronary artery tissues were collected and divided into control (CON), coronary heart disease (CHD) and sudden coronary death (SCD) groups. Pathologic changes (including changes in the coronary plaque area, necrotic core, collagen fibers, and foam cell content) were observed. The LTF, P62, and 4-hydroxynonenal (4-HNE) expression levels were assessed. The ApoE^–/– AS mouse model was established. The pathological changes and related protein levels were analyzed after autophagy inhibition. The foam cell model was constructed using an ox-LDL-induced human monocyte line, THP-1. The LTF, BECN1, LC3-II/I, AMP-activated protein kinase (AMPK)/the mammalian target of rapamycin (mTOR) pathway proteins, B-cell lymphoma-2 (Bcl-2), Bcl-2-associated X protein (Bax), and 4-HNE expressions were then detected after silencing of LTF or BECN1. Plaque stability was significantly lower in the SCD group compared to the non-SCD group (p < 0.05). LTF, P62 and 4-HNE levels in plaques increased as plaque stability decreased, and LTF was significantly correlated with plaque progression and autophagy levels. Autophagy inhibition by U0126 leads to the worsening of aortic luminal stenosis, increased necrotic core and foam cell deposits, decreased autophagosomes, reduced LTF expression, and upregulated P62 expression in AS mice. It was further demonstrated that LTF expression correlates with autophagy. LTF expression was increased in ox-LDL-treated THP-1 cells, and silencing BECN1 and/or LTF increased mTOR phosphorylation and 4-HNE levels, inhibited BECN1 and LC3 II expression and AMPK activation, and simultaneously decreased the Bcl-2/Bax ratio. LTF might alleviate AS pathology through accelerating the AMPK/mTOR pathway, and suggested that LTF may be a potential predictive molecule for AS.

BACKGROUND:It has been reported that polysaccharides have potential novel anti-cancer properties. Previously, we confirmed that Dictyophora polysaccharides could significantly inhibit liver transplantation tumors in mice. However, the mechanism of Dictyophora polysaccharide action on human liver cancer is unclear. Here, we aimed to clarify the mechanism of Dictyophora polysaccharide action on human hepatocellular carcinoma cells, namely the effect on cell proliferation, the cell cycle, and apoptosis, and on the apoptosis-related genes and proteins in vitro. MATERIAL AND METHODS:The HCC-LM3 cell line was incubated with 2.5 mg/mL Dictyophora polysaccharides for 24, 48, and 72 h. The cell growth inhibition rate was evaluated using Cell Counting Kit-8. Cell cycle and apoptosis were measured with flow cytometry. The expression of apoptosis-related genes and proteins was measured using real-time fluorescence quantitative polymerase chain reaction (RT-qPCR) and Western blotting, respectively. RESULTS:The Dictyophora polysaccharides inhibited HCC-LM3 cell proliferation in a time- and dose-dependent manner and blocked the cell cycle in the G₂/M phase. In addition, Bax and caspase-3 expression were significantly increased after Dictyophora polysaccharides treatment. CONCLUSIONS:To the best of our knowledge, this is the first published study on the mechanism of Dictyophora polysaccharide inhibition of HCC-LM3 cell proliferation.