4-cholesten-3-one suppresses lung adenocarcinoma metastasis by regulating translocation of HMGB1, HIF1α and Caveolin-1

Integrating network pharmacology with molecular docking to rationalize the ethnomedicinal use of Alchornea laxiflora (Benth.) Pax & K. Hoffm. for efficient treatment of depression

Background: Alchornea laxiflora (Benth.) Pax & K. Hoffm. (A. laxiflora) has been indicated in traditional medicine to treat depression. However, scientific rationalization is still lacking. Hence, this study aimed to investigate the antidepressant potential of A. laxiflora using network pharmacology and molecular docking analysis. Materials and methods: The active compounds and potential targets of A. laxiflora and depression-related targets were retrieved from public databases, such as PubMed, PubChem, DisGeNET, GeneCards, OMIM, SwissTargetprediction, BindingDB, STRING, and DAVID. Essential bioactive compounds, potential targets, and signaling pathways were predicted using in silico analysis, including BA-TAR, PPI, BA-TAR-PATH network construction, and GO and KEGG pathway enrichment analysis. Later on, with molecular docking analysis, the interaction of essential bioactive compounds of A. laxiflora and predicted core targets of depression were verified. Results: The network pharmacology approach identified 15 active compounds, a total of 219 compound-related targets, and 14,574 depression-related targets with 200 intersecting targets between them. SRC, EGFR, PIK3R1, AKT1, and MAPK1 were the core targets, whereas 3-acetyloleanolic acid and 3-acetylursolic acid were the most active compounds of A. laxiflora with anti-depressant potential. GO functional enrichment analysis revealed 129 GO terms, including 82 biological processes, 14 cellular components, and 34 molecular function terms. KEGG pathway enrichment analysis yielded significantly enriched 108 signaling pathways. Out of them, PI3K-Akt and MAPK signaling pathways might have a key role in treating depression. Molecular docking analysis results exhibited that core targets of depression, such as SRC, EGFR, PIK3R1, AKT1, and MAPK1, bind stably with the analyzed bioactive compounds of A. laxiflora. Conclusion: The present study elucidates the bioactive compounds, potential targets, and pertinent mechanism of action of A. laxiflora in treating depression. A. laxiflora might exert an antidepressant effect by regulating PI3K-Akt and MAPK signaling pathways. However, further investigations are required to validate.

Effects of cholesterol oxidase on neurotransmission and acetylcholine levels at the mice neuromuscular junctions

Membrane cholesterol oxidation is a hallmark of redox and metabolic imbalance, and it may accompany neurodegenerative disorders. Using microelectrode recordings of postsynaptic responses as well as fluorescent dyes for monitoring synaptic vesicle cycling and membrane properties, the action of enzymatic cholesterol oxidation on neuromuscular transmission was studied in the mice diaphragms. Cholesterol oxidase (ChO) at low concentration disturbed lipid-ordering specifically in the synaptic membranes, but it did not change markedly spontaneous exocytosis and evoked release in response to single stimuli. At low external Ca2+ conditions, analysis of single exocytotic events revealed a decrease in minimal synaptic delay and the probability of exocytosis upon plasmalemmal cholesterol oxidation. At moderate- and high-frequency activity, ChO treatment enhanced both neurotransmitter and FM-dye release. Furthermore, it precluded a change in exocytotic mode from full-fusion to kiss-and-run during high-frequency stimulation. Accumulation of extracellular acetylcholine (without stimulation) dependent on vesamicol-sensitive transporters was suppressed by ChO. The effects of plasmalemmal cholesterol oxidation on both neurotransmitter/dye release at intense activity and external acetylcholine levels were reversed when synaptic vesicle membranes were also exposed to ChO (i.e., the enzyme treatment was combined with induction of exo-endocytotic cycling). Thus, we suggest that plasmalemmal cholesterol oxidation affects exocytotic machinery functioning, enhances synaptic vesicle recruitment to the exocytosis and decreases extracellular neurotransmitter levels at rest, whereas ChO acting on synaptic vesicle membranes suppresses the participation of the vesicles in the subsequent exocytosis and increases the neurotransmitter leakage. The mechanisms underlying ChO action can be related to the lipid raft disruption.

Lipid metabolism in malignant tumor brain metastasis: reprogramming and therapeutic potential

INTRODUCTION

Brain metastasis is a highly traumatic event in the progression of malignant tumors, often symbolizing higher mortality. Metabolic alterations are hallmarks of cancer, and the mask of lipid metabolic program rearrangement in cancer progression is gradually being unraveled.

AREAS COVERED

In this work, we reviewed clinical and fundamental studies related to lipid expression and activity changes in brain metastases originating from lung, breast, and cutaneous melanomas, respectively. Novel roles of lipid metabolic reprogramming in the development of brain metastasis from malignant tumors were identified and its potential as a therapeutic target was evaluated. Published literature and clinical studies in databases consisting of PubMed, Embase, Scopus and www.ClinicalTrials.gov from 1990 to 2022 were searched.

EXPERT OPINION

Lipid metabolic reprogramming in brain metastasis is involved in de novo lipid synthesis within low lipid availability environments, regulation of lipid uptake and storage, metabolic interactions between brain tumors and the brain microenvironment, and membrane lipid remodeling, in addition to being a second messenger for signal transduction. Although some lipid metabolism modulators work efficiently in preclinical models, there is still a long way to go from laboratory to clinic. This area of research holds assurance for the organ-targeted treatment of brain metastases through drug-regulated metabolic targets and dietary interventions.

Caveolin-1 suppresses hippocampal neuron apoptosis via the regulation of HIF1α in hypoxia in naked mole-rats

Naked mole-rats (NMRs) (Heterocephalus glaber) are highly social and subterranean rodents with large communal colonies in burrows containing low oxygen levels. The inhibition of severe hypoxic conditions is of particular interest to this study. To understand the mechanisms that facilitate neuronal preservation during hypoxia, we investigated the proteins regulating hypoxia tolerance in NMR hippocampal neurons. Caveolin-1 (Cav-1), a transmembrane scaffolding protein, confers prosurvival signalling in the central nervous system. The present study aimed to investigate the role of Cav-1 in hypoxia-induced neuronal injury. Western blotting analysis and immunocytochemistry showed that Cav-1 expression was significantly upregulated in NMR hippocampal neurons under 8% O₂ conditions for 8 h. Cav-1 alleviates apoptotic neuronal death from hypoxia. Downregulation of Cav-1 by lentiviral vectors suggested damage to NMR hippocampal neurons under hypoxic conditions in vitro and in vivo. Overexpression of Cav-1 by LV-Cav-1 enhanced hypoxic tolerance of NMR hippocampal neurons in vitro and in vivo. Mechanistically, the levels of hypoxia inducible factor-1α (HIF-1α) are also increased under hypoxic conditions. After inhibiting the binding of HIF-1α to hypoxia response elements in the DNA by echinomycin, Cav-1 levels were downregulated significantly. Furthermore, chromatin immunoprecipitation assays showed the direct role of HIF1α in regulating the expression levels of Cav-1 in NMR hippocampal neurons under hypoxic conditions. These findings suggest that Cav-1 plays a critical role in modulating the apoptosis of NMR hippocampal neurons and warrant further studies targeting Cav-1 to treat hypoxia-associated brain diseases.

27-hydroxycholesterol linked high cholesterol diet to lung adenocarcinoma metastasis

Dietary cholesterol has been implicated to promote lung cancer. Lung adenocarcinoma (LAC) is a main type of lung cancer, whereas the functional mechanism of cholesterol in LAC remained largely unknown. In the present study, we evidenced that cholesterol promoted cell proliferation and invasion of LAC in vitro as well as LAC metastasis in vivo. Cyp27A1 knockdown reduced the cholesterol-induced LAC cells proliferation and invasion. In contrast, Cyp7B1 knockdown enhanced the effect of cholesterol on LAC cells proliferation and invasion. Furthermore, Cyp27A1 deficiency remarkably reduced high cholesterol-induced LAC metastasis in vivo. Mechanism investigation demonstrated that exposure of LAC cells to 27-hydroxycholesterol induced the phosphorylation of AKT and NFκB p65, and promoted the expression of peptidylprolyl isomerase B (PPIB), especially in the coculture with THP1-derived macrophage. Meanwhile, 27-hydroxycholesterol induced the secretion of FGF2 and IL-6, which contributed to the expression of snail and vimentin. Luciferase report assay and ChIP assay confirmed that NFκB p65 controlled the transcription of PPIB. Inhibiting NFκB p65 activation reduced PPIB expression. PPIB inhibition reduced 27-hydroxycholesterol-induced expression of snail and vimentin. These results indicated that 27-hydroxycholesterol linked high cholesterol and LAC metastasis by regulating NFκB/PPIB axis and the secretion of FGF2 and IL-6.

miR-142-3p simultaneously targets HMGA1, HMGA2, HMGB1, and HMGB3 and inhibits tumorigenic properties and in-vivo metastatic potential of human cervical cancer cells

AIMS

High-mobility group (HMG) proteins are oncogenic in different cancers, including cervical cancer; silencing their individual expression using sh-RNAs, siRNAs, and miRNAs has had anti-tumorigenic effects, but the consequences of their collective downregulation are not known. Since multiple gene targeting is generally very effective in cancer therapy, the present study highlighted the consequences of silencing the expression of HMGA1, A2, B1, and B3 using sh-RNAs or miR-142-3p (that can potentially target HMGA1, A2, B1, and B3) in cervical cancer cell lines.

MAIN METHODS

3' UTR luciferase reporter assays were performed to validate HMGA1, A2, B1, and B3 as targets of miR-142-3p in human cervical cancer cells. Annexin V/PI dual staining and flow cytometry analyses were used to detect apoptotic cells. miR-142-3p-mediated regulation of cell death, colony formation, migration, and invasion was investigated in human cervical cancer cells together with in vivo metastasis in zebrafish.

KEY FINDINGS

Concurrent knockdown of HMGA1, A2, B1, and B3 through their corresponding sh-RNAs inhibited cell viability and colony formation but induced apoptosis, and these effects were relatively reduced upon their individual knockdown. miR-142-3p targeted HMGA1, A2, B1, and B3 by binding to their 3'UTRs and induced apoptosis but inhibited proliferation, migration, and invasion of human cervical cancer cells. In addition, miR-142-3p expression decreased phospho-p65 and EMT-related proteins in cervical cancer cells and their in vivo metastatic potential upon implantation in zebrafish.

SIGNIFICANCE

These findings suggest that miR-142-3p acts as a tumor-suppressive miRNA by targeting HMGA1, A2, B1, and B3 and may serve as a potential therapeutic agent in human cervical cancer.

Metabolities from Marine Sponges of the Genus Callyspongia: Occurrence, Biological Activity, and NMR Data

The genus Callyspongia (Callyspongiidae) encompasses a group of demosponges including 261 described species, of which approximately 180 have been accepted after taxonomic reviews. The marine organisms of Callyspongia are distributed in tropical ecosystems, especially in the central and western Pacific, but also in the regions of the Indian, the West Atlantic, and the East Pacific Oceans. The reason for the interest in the genus Callyspongia is related to its potential production of bioactive compounds. In this review, we group the chemical information about the metabolites isolated from the genus Callyspongia, as well as studies of the biological activity of these compounds. Through NMR data, 212 metabolites were identified from genus Callyspongia (15 species and Callyspongia sp.), belonging to classes such as polyacetylenes, terpenoids, steroids, alkaloids, polyketides, simple phenols, phenylpropanoids, nucleosides, cyclic peptides, and cyclic depsipeptides. A total of 109 molecules have been reported with bioactive activity, mainly cytotoxic and antimicrobial (antibacterial and antifungal) action. Thus, we conclude that polyacetylenes, terpenoids and steroids correspond to the largest classes of compounds of the genus, and that future research involving the anticancer action of the species' bioactive metabolites may become relevant.

Cytotoxic activity of cholesterol oxidase produced by Streptomyces sp. AKHSS against cancerous cell lines: mechanism of action in HeLa cells

Re-occurrence of cancer is the major drawback for the currently available anticancer therapies. Therefore, study of an efficient enzyme, cholesterol oxidase produced by various kinds of microbes especially obtained from unexplored marine actinobacterial species against human cancer cell lines and understanding its mechanism of action helps to identify an irreversible and potent anticancer agent. The cytotoxic potential of cholesterol oxidase produced by a marine Streptomyces sp. AKHSS against four different human cancer cell lines was demonstrated through MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] assay. Fluorescent confocal microscopy and flow cytometry based experiments were performed to understand the efficiency of the enzymatic action on HeLa cells. Further, the apoptotic related proteins were detected through western blotting. Interestingly, the enzyme exhibited potent cytotoxicity at very low concentrations (0.093-0.327 µM) against all the cells tested. Fluorescent confocal microscopy revealed the morphological variations induced by the enzyme on cancer cell lines such as the formation of lipid droplets and condensation of nuclei. The enzyme treated cell-free extracts of HeLa cells analyzed through gas chromatography mass spectrometry showed the depletion of membrane cholesterol and the presence of substituted enzyme oxidized product, cholest-4-ene-3-one. The enzyme had induced significant inhibitory effects on the cell viability such as cell cycle arrest (G₁ phase), apoptosis and rise of reactive oxygen species as evident through flow cytometry. Besides, hyperpolarization of mitochondrial membrane, reduced rates of phosphorylation of pAkt and the expression of apoptotic death markers like Fas, Fas L, caspases (8 and 3) and PARP-1 were recorded in the enzyme treated HeLa cells. Thus, cholesterol oxidase purified from a marine Streptomyces sp. AKHSS exhibits potent cytotoxicity at very low concentrations against human cancer cell lines. All the ex vivo experiments portrayed the substantial inhibitory effect of the enzyme on HeLa cells suggesting that cholesterol oxidase of Streptomyces sp. AKHSS could be a prominent cancer chemotherapeutic agent.

Multimodal evaluation of hypoxia in brain metastases of lung cancer and interest of hypoxia image-guided radiotherapy

Lung cancer patients frequently develop brain metastases (BM). Despite aggressive treatment including neurosurgery and external-radiotherapy, overall survival remains poor. There is a pressing need to further characterize factors in the microenvironment of BM that may confer resistance to radiotherapy (RT), such as hypoxia. Here, hypoxia was first evaluated in 28 biopsies from patients with non‑small cell lung cancer (NSCLC) BM, using CA-IX immunostaining. Hypoxia characterization (pimonidazole, CA-IX and HIF-1α) was also performed in different preclinical NSCLC BM models induced either by intracerebral injection of tumor cells (H2030-Br3M, H1915) into the cortex and striatum, or intracardial injection of tumor cells (H2030-Br3M). Additionally, [18F]-FMISO-PET and oxygen-saturation-mapping-MRI (SatO2-MRI) were carried out in the intracerebral BM models to further characterize tumor hypoxia and evaluate the potential of Hypoxia-image-guided-RT (HIGRT). The effect of RT on proliferation of BM ([18F]-FLT-PET), tumor volume and overall survival was determined. We showed that hypoxia is a major yet heterogeneous feature of BM from lung cancer both preclinically and clinically. HIGRT, based on hypoxia heterogeneity observed between cortical and striatal metastases in the intracerebrally induced models, showed significant potential for tumor control and animal survival. These results collectively highlight hypoxia as a hallmark of BM from lung cancer and the value of HIGRT in better controlling tumor growth.

Sanguisorba officinalis L. Suppresses Triple-Negative Breast Cancer Metastasis by Inhibiting Late-Phase Autophagy via Hif-1α/Caveolin-1 Signaling

Sanguisorba officinalis L. (SA) is a common herb for cancer treatment in the clinic, particularly during the consolidation phase to prevent occurrence or metastasis. Nevertheless, there are limited studies reporting the molecular mechanisms about its anti-metastatic function. It is well demonstrated that autophagy is one of the critical mechanisms accounting for metastasis and anti-cancer pharmacological actions of Chinese herbs. On the threshold, the regulatory effects and molecular mechanisms of SA in suppressing autophagy-related breast cancer metastasis were investigated in this study. In vitro findings demonstrated that SA potently suppressed the proliferation, colony formations well as metastasis process in triple-negative breast cancer. Network and biological analyses predicted that SA mainly targeted caveolin-1 (Cav-1) to induce anti-metastatic effects, and one of the core mechanisms was via regulation of autophagy. Further experiments—including western blotting, transmission electron microscopy, GFP-mRFP-LC3 immunofluorescence, and lysosomal-activity detection—validated SA as a potent late-stage autophagic inhibitor by increasing microtubule-associated light chain 3-II (LC3-II) conversion, decreasing acidic vesicular-organelle formation, and inducing lysosomal dysfunction even under conditions of either starvation or hypoxia. Furthermore, the anti-autophagic and anti-metastatic activity of SA was Cav-1-dependent. Specifically, Cav-1 knockdown significantly facilitated SA-mediated inhibition of autophagy and metastasis. Furthermore, hypoxia inducible factor-1α (Hif-1α) overexpression attenuated the SA-induced inhibitory activities on Cav-1, autophagy, and metastasis, indicating that SA may have inhibited autophagy-related metastasis via Hif-1α/Cav-1 signaling. In both mouse breast cancer xenograft and zebrafish xenotransplantation models, SA inhibited breast cancer growth and inhibited late-phase autophagy in vivo, which was accompanied by suppression of Hif-1α/Cav-1 signaling and the epithelial-mesenchymal transition. Overall, our findings not only indicate that SA acts as a novel late-phase autophagic inhibitor with anti-metastatic activities in triple-negative breast cancer, but also highlight Cav-1 as a regulator in controlling late-phase autophagic activity.

Water-soluble fraction of particulate matter <2.5 μm promoted lung epithelia cells apoptosis by regulating the expression of caveolin-1 and Krüppel-like factor 5

Ambient fine particulate matter of <2.5 μm (PM2.5) has been linked to morbidity and mortality from respiratory and cardiovascular diseases. Lung epithelial cells bear the brunt of PM2.5 exposure. In the present study, we found that exposure of A549 cells to the water-soluble fraction of PM2.5 (WS-PM2.5) promoted the expression and internalization of caveolin-1. Caveolin-1 knockdown restrained the endocytosis of WS-PM2.5. In addition, WS-PM2.5 accumulation in the cells induced the phosphorylation of serine/threonine protein kinase B (AKT) and nuclear factor κ-light-chain enhancer of activated B cells (NFκB), as well as the expression of Krüppel-like factor 5 (KLF5). Inhibiting activation of AKT and NFκB also partly reduced WS-PM2.5 concentration in cells, but KLF5 knockdown did not affect the intracellular accumulation of WS-PM2.5. KLF5 knockdown suppressed cytochrome P450 family 1 subfamily A member 1 (CYP1A1) expression and activated caspase 3. Luciferase reporter assay and chromatin immunoprecipitation assay showed that KLF5 positively regulated the transcription of KLF5. These results suggested that caveolin-1 was required for the endocytosis of WS-PM2.5. Intracellular accumulation of WS-PM2.5 activated AKT and NFκB, which facilitated WS-PM2.5 endocytosis. WS-PM2.5 accumulation also induced KLF5 expression, increasing the transcriptional expression of CYP1A1, which contributed to activate caspase 3.

HMGB1 and Caveolin-1 related to RPE cell senescence in age-related macular degeneration

Accumulation of lipofuscin in the retinal pigment epithelium (RPE) is considered a major cause of RPE dysfunction and senescence in age-related macular degeneration (AMD), and N-retinylidene-N-retinylethanolamine (A2E) is the main fluorophore identified in lipofuscin from aged human eyes. Here, human-induced pluripotent stem cell (iPSC)-RPE was generated from healthy individuals to reveal proteomic changes associated with A2E-related RPE cell senescence. A novel RPE cell senescence-related protein, high-mobility group box 1 (HMGB1), was identified based on proteomic mass spectrometry measurements on iPSC-RPE with A2E treatment. Furthermore, HMGB1 upregulated Caveolin-1, which also was related RPE cell senescence. To investigate whether changes in HMGB1 and Caveolin-1 expression under A2E exposure contribute to RPE cell senescence, human ARPE-19 cells were stimulated with A2E; expression of HMGB1, Caveolin-1, tight junction proteins and senescent phenotypes were verified. HMGB1 inhibition alleviated A2E induced cell senescence. Migration of RPE cells was evaluated. Notably, A2E less than or equal to 10μM induced both HMGB1 and Caveolin-1 protein upregulation and HMGB1 translocation, while Caveolin-1 expression was downregulated when there was more than 10μM A2E. Our data indicate that A2E-induced upregulation of HMGB1、Caveolin-1 and HMGB1 release may relate to RPE cell senescence and play a role in the pathogenesis of AMD.

miR-4510 acts as a tumor suppressor in gastrointestinal stromal tumor by targeting APOC2

Dysregulation of microRNAs (miRNAs) expression has been demonstrated in gastrointestinal stromal tumor (GIST). In this study, we aimed to determine the differential miRNAs expression in GISTs and explore the functional mechanism of differential miRNAs in GIST cells. We measured differential miRNAs in six pairs of GIST tissues and matched adjacent tissues through a high-throughput sequencing, which was confirmed in 64 pairs of GIST tissues and adjacent tissues by real-time polymerase chain reaction. We found that miR-4510 expression was significantly downregulated in GIST tissues compared to matched control tissues. Luciferase reporter assay identified apolipoprotein C-II (APOC2) as a direct target of miR-4510. Overexpression of miR-4510 inhibited the mRNA and protein expression of APOC2. In addition, overexpression of miR-4510 suppressed GIST cell proliferation, migration, and invasion. Overexpression of miR-4510 also inhibited the phosphorylation of AKT and ERK1/2, reduced the expression of matrix metallopeptidase 2 (MMP2) and MMP9. APOC2 knockdown mimicked the effect of miR-4510 overexpression. Further investigation confirmed that APOC2 was notably upregulated in GIST tissues compared to adjacent control tissues. These results suggested that miR-4510 downregulation could promote GIST progression, including growth, invasion, and metastasis, through increasing APOC2 expression.

4-cholesten-3-one decreases breast cancer cell viability and alters membrane raft-localized EGFR expression by reducing lipogenesis and enhancing LXR-dependent cholesterol transporters

Background

The alteration of lipid metabolism in cancer cells is recognized as one of the most important metabolic hallmarks of cancer. Membrane rafts defined as plasma membrane microdomains enriched in cholesterol and sphingolipids serve as platforms for signaling regulation in cancer. The main purpose of this study was to evaluate the effect of the cholesterol metabolite, 4-cholesten-3-one, on lipid metabolism and membrane raft integrity in two breast cancer cell lines, MCF-7 and MDA-MB-231. Its ability to reduce cell viability and migration has also been investigated.

Methods

RT-qPCR was performed to evaluate the expression of enzymes involved in lipogenesis and cholesterol synthesis, and ABCG1 and ABCA1 transporters involved in cholesterol efflux. Its effect on cell viability and migration was studied using the MTT assay, the wound healing assay and the Transwell migration assay, respectively. The effect of 4-cholesten-3-one on membrane rafts integrity was investigated by studying the protein expression of flotillin-2, a membrane raft marker, and raft-enriched EGFR by western blot.

Results

Interestingly, we found that 4-cholesten-3-one treatment decreased mRNA expression of different enzymes including ACC1, FASN, SCD1 and HMGCR. We further demonstrated that 4-cholesten-3-one increased the expression of ABCG1 and ABCA1. We also found that 4-cholesten-3-one decreased the viability of MCF-7 and MDA-MB-231 cells. This effect was neutralized after treatment with LXR inverse agonist or after LXRβ knockdown by siRNA. As a result, we also demonstrated that 4-cholesten-3-one disrupts membrane rafts and cell migration capacity.

Conclusion

Our results show that 4-cholesten-3-one exerts promising antitumor activity by altering LXR-dependent lipid metabolism in breast cancer cells without increasing lipogenesis.

27-Hydroxycholesterol enhanced osteoclastogenesis in lung adenocarcinoma microenvironment

27-Hydroxycholesterol (27-HC) has been implicated in the pathological process of estrogen receptor positive breast cancer. However, the role of 27-HC in lung adenocarcinoma is still unclear. Because bone metastasis is a main reason for the high mortality of lung adenocarcinoma, this study aimed to investigate the effect of 27-HC on osteoclastogenesis in lung adenocarcinoma microenvironment. The results showed that the conditioned media (CM) from lung adenocarcinoma cells cocultured with macrophages promoted osteoclast differentiation, which was enhanced by 27-HC. Further investigation showed that CM inhibited miR-139 expression and promoted c-Fos expression. Luciferase reporter assay identified c-Fos as a direct target of miR-139. CM also induced the expression and nuclear translocation of NFATc1 and STAT3 phosphorylation, which was enlarged by 27-HC but was attenuated by miR-139. Coimmunoprecipitation assay demonstrated that 27-HC increased the interaction between NFATc1 and phosphorylated STAT3, which was restricted by miR-139. Chromatin immunoprecipitation assay showed that pSTAT3 could bind to the promoter of c-Fos, c-Fos could bind to the promoter of NFATc1, and both pSTAT3 and NFATc1 could bind to the promoter of Oscar, which were enlarged by 27-HC but were blocked by miR-139. Knockdown of c-Fos mimicked the effect of miR-139. These results suggested that CM, especially containing 27-HC, promoted osteoclastogenesis by inhibiting miR-139 expression and activating the STAT3/c-Fos/NFATc1 pathway.

Ox-LDL induces endothelial cell apoptosis and macrophage migration by regulating caveolin-1 phosphorylation

Oxidative low-density lipoprotein (ox-LDL) is a risk factor for atherosclerosis. Ox-LDL leads to endothelial injury in the initial stage of atherosclerosis. In this study, we investigated the role of ox-LDL in endothelial injury and macrophage recruitment. We demonstrated that ox-LDL promoted a dose-dependent phosphorylation of caveolin-1 in human umbilical vein endothelial cells. Phosphorylated caveolin-1 increased ox-LDL uptake. Intracellular accumulation of ox-LDL induced NF-κB p65 phosphorylation, promoted HMGB1 translocation from nucleus to cytoplasm and cytochrome C release from mitochondria to cytoplasm, and activated caspase 3, resulting in cell apoptosis. NF-κB activation also facilitated cavolin-1 phosphorylation and HMGB1 expression. In addition, caveolin-1 phosphorylation favored HMGB1 release and nuclear translocation of EGR1. Nuclear translocation of EGR1 contributed to cytoplasmic translocation of HMGB1. The extracellular HMGB1 induced the migration of PMBC-derived macrophages toward HUVECs in a TLR4-dependent manner. Our results suggested that ox-LDL promoted HUVECs apoptosis and macrophage recruitment by regulating caveolin-1 phosphorylation.

Effects of purified Omphalia lapidescens protein on metastasis, cell cycle, apoptosis and the JAK-STAT signaling pathway in SGC-7901 human gastric cells

Gastric cancer is one of the most common cancers globally with high rates of morbidity and mortality. Purified Omphalia lapidescens protein (pPeOp) is a protein extracted from the sclerotium of Omphalia lapidescens. The present study aimed to investigate the effects of pPeOp on the viability, migration, cell cycle progression and apoptosis of SGC-7901 cells. The expression of numerous proteins, namely matrix metallopeptidase (MMP)2, MMP9, p53, caspase-3, B-cell lymphoma (Bcl)-2, cyclin A2, cyclin B1, cyclin D1, cyclin dependent kinase (CDK)1, CDK2 and CDK4, were investigated using western blot analysis and reverse transcription-quantitative polymerase chain reaction. The results of the present study demonstrated that treating SGC-7901 cells with pPeOp markedly suppressed their migration, induced their apoptosis and arrested their progression in S phase. pPeOp also downregulated the expression of migration-associated proteins (MMP2 and MMP9) and cyclin-associated proteins (cyclin A2, cyclin B1, cyclin D1, CDK1, CDK2 and CDK4) in a dose-dependent manner. Cells treated with pPeOp significantly upregulated caspase-3 and p53 and downregulated Bcl-2. Finally, the impact of pPeOp on three key nodes of the Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway were investigated and it was revealed that expression levels of JAK1, JAK2 and STAT3 were significantly downregulated following treatment. Together, the results of the present study suggested that pPeOp suppresses metastasis, arrests cell cycle, induces apoptosis and inhibits the JAK-STAT signaling pathway in SGC-7901 cells. Therefore, pPeOp may serve as a novel therapeutic agent for patients with gastric cancer.

Caveolin-1 promotes pituitary adenoma cells migration and invasion by regulating the interaction between EGR1 and KLF5

Caveolin-1 (Cav-1) is a principal structural protein of caveolae. Cav-1 has been implicated in cancer progression, but its precise functional roles in pituitary adenoma cells remain largely unclear. In this study, we evidenced that the level of cav-1 was elevated in the invasive pituitary adenoma. Cav-1 knockdown restrained the migration and invasion of pituitary adenoma cells. In cav-1-depleting cells, the expression of miR-145, miR-124 and miR-183 were up-regulated. Further investigation showed that cav-1 knockdown inhibited the nuclear translocation of EGR1, reducing the interaction between EGR1 and KLF5. The resulting free KLF5 promoted the expression of miR-145, miR-124 and miR-183 by binding to their promoters, which was blocked by EGR1. Luciferase reporter assay indicated that miR-145 targeted FSCN1, miR-124 targeted PTTG1IP, and miR-183 targeted EZR in pituitary adenoma cells, respectively. Knockdown of FSCN1, PTTG1IP or EZR suppressed the migration and invasion of pituitary adenoma cells. In conclusion, our data suggested that the elevated cav-1 promoted pituitary adenoma cells migration and invasion by regulating the interaction between EGR1 and KLF5.

LncRNA-DANCR contributes to lung adenocarcinoma progression by sponging miR-496 to modulate mTOR expression

Long non‐coding RNAs (lncRNAs) have emerged as new and important regulators of pathological processes including tumour development. In this study, we demonstrated that differentiation antagonizing non‐protein coding RNA (DANCR) was up‐regulated in lung adenocarcinoma (ADC) and that the knockdown of DANCR inhibited tumour cell proliferation, migration and invasion and restored cell apoptosis rescued; cotransfection with a miR‐496 inhibitor reversed these effects. Luciferase reporter assays showed that miR‐496 directly modulated DANCR; additionally, we used RNA‐binding protein immunoprecipitation (RIP) and RNA pull‐down assays to further confirm that the suppression of DANCR by miR‐496 was RISC‐dependent. Our study also indicated that mTOR was a target of miR‐496 and that DANCR could modulate the expression levels of mTOR by working as a competing endogenous RNA (ceRNA). Furthermore, the knockdown of DANCR reduced tumour volumes in vivo compared with those of the control group. In conclusion, this study showed that DANCR might be an oncogenic lncRNA that regulates mTOR expression through directly binding to miR‐496. DANCR may be regarded as a biomarker or therapeutic target for ADC.

Rational design of cholesterol oxidase for efficient bioresolution of cholestane skeleton substrates

Cholesterol oxidase catalyzes the oxidation and isomerization of the cholestane substrates leading to the addition of a hydroxyl group at the C3 position. Rational engineering of the cholesterol oxidase from Pimelobacter simplex (PsChO) was performed. Mutagenesis of V64 and F70 improved the catalytic activities toward cholestane substrates. Molecular dynamics simulations, together with structure-activity relationship analysis, revealed that both V64C and F70V increased the binding free energy between PsChO mutants and cholesterol. F70V and V64C mutations might cause the movement of loops L56-P77, K45-P49 and L350-E354 at active site. They enlarged the substrate-binding cavity and relieved the steric interference with substrates facilitating recognition of C17 hydrophobic substrates with long side chain substrates.

Novel crosstalk between KLF4 and ZEB1 regulates gemcitabine resistance in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal malignancies with broad resistance to chemotherapeutic drugs. Krüppel-like factor 4 (KLF4) is a candidate tumor suppressor in PDAC. However, the precise role of KLF4 in gemcitabine resistance of PDAC remains largely unclear. In this study, we demonstrated that gemcitabine inhibited KLF4 expression. Moreover, gemcitabine also reduced the levels of miR‑200b and miR‑183, but promoted ZEB1 expression in PDAC cells. KLF4 knockdown blocked the expression of miR‑200b and miR‑183, and inversely, KLF4 overexpression promoted the expression of miR‑200b and miR‑183, suggesting that KLF4 positively regulated the expression of miR‑200b and miR‑183. Moreover, KLF4 knockdown enhanced ZEB1 expression and gemcitabine resistance while KLF4 overexpression induced the opposite effect. ChIP assays verified that KLF4 positively regulated the expression of miR‑200b and miR‑183 by directly binding to their promoters. Then, miR‑200b and miR‑183 directly inhibited ZEB1 expression by targeting its 3'UTR region. ZEB1 knockdown attenuated gemcitabine resistance in PDAC cells. KLF4 overexpression promoted gemcitabine sensitivity of PDAC in vivo by negatively regulating ZEB1 expression. Our results revealed that novel crosstalk between KLF4 and ZEB1 regulated gemcitabine resistance in PDAC.

25-Hydroxycholesterol promotes migration and invasion of lung adenocarcinoma cells

25-hydroxycholesterol (25-HC) is enzymatically produced by cholesterol 25-hydorxylase in various organs and is involved in many processes, including lipid metabolism, inflammation and the immune response. However, the role of 25-HC in the migration and invasion of lung adenocarcinoma (ADC) cells remains largely unknown. In this study, we demonstrated that 0.1 μM 25-HC promoted ADC cell migration and invasion without affecting cell proliferation, especially after coculture with THP1-derived macrophages. Further investigation showed that 0.1 μM 25-HC significantly stimulated interleukin-1β (IL-1β) secretion in a coculture system and increased the expression of LXR and Snail. IL-1β also mimicked the effect of 25-HC. LXR knockdown notably blocked the 25-HC-induced Snail expression, migration and invasion in both the monoculture system and the coculture system, but it did not impact the effect of IL-1β, which suggested that IL-1β functioned in an LXR-independent manner. These results suggested that 25-HC promoted ADC cell migration and invasion in an LXR-dependent manner in the monoculture system but that in the coculture system, the 25-HC-induced IL-1β secretion enhanced the effect of 25-HC in an LXR-independent manner.