Wnt3a Promotes the Vasculogenic Mimicry Formation of Colon Cancer via Wnt/β-Catenin Signaling

Our previous study provided evidence that non-canonical Wnt signaling is involved in regulating vasculogenic mimicry (VM) formation. However, the functions of canonical Wnt signaling in VM formation have not yet been explored. In this study, we found the presence of VM was related to colon cancer histological differentiation (p < 0.001), the clinical stage (p < 0.001), and presence of metastasis and recurrence (p < 0.001). VM-positive colon cancer samples showed increased Wnt3a expression (p < 0.001) and β-catenin nuclear expression (p < 0.001) compared with the VM-negative samples. In vitro, over-regulated Wnt3a expression in HT29 colon cancer cells promoted the capacity to form tube-like structures in the three-dimensional (3-D) culture together with increased expression of endothelial phenotype-associated proteins such as VEGFR2 and VE-cadherin. The mouse xenograft model showed that Wnt3a-overexpressing cells grew into larger tumor masses and formed more VM than the control cells. In addition, the Wnt/β-catenin signaling antagonist Dickkopf-1(Dkk1) can reverse the capacity to form tube-like structures and can decrease the expressions of VEGFR2 and VE-cadherin in Wnt3a-overexpressing cells. Taken together, our results suggest that Wnt/β-catenin signaling is involved in VM formation in colon cancer and might contribute to the development of more accurate treatment modalities aimed at VM.     

GLP-2 Attenuates LPS-Induced Inflammation in BV-2 Cells by Inhibiting ERK1/2, JNK1/2 and NF-κB Signaling Pathways

The pathogenesis of Parkinson’s disease (PD) often involves the over-activation of microglia. Over-activated microglia could produce several inflammatory mediators, which trigger excessive inflammation and ultimately cause dopaminergic neuron damage. Anti-inflammatory effects of glucagon-like peptide-2 (GLP-2) in the periphery have been shown. Nonetheless, it has not been illustrated in the brain. Thus, in this study, we aimed to understand the role of GLP-2 in microglia activation and to elucidate the underlying mechanisms. BV-2 cells were pretreated with GLP-2 and then stimulated by lipopolysaccharide (LPS). Cells were assessed for the responses of pro-inflammatory enzymes (iNOS and COX-2) and pro-inflammatory cytokines (IL-1β, IL-6 and TNF-α); the related signaling pathways were evaluated by Western blotting. The rescue effect of GLP-2 on microglia-mediated neurotoxicity was also examined. The results showed that GLP-2 significantly reduced LPS-induced production of inducible nitric oxide synthase (iNOS), cyclooxygenase-s (COX-2), IL-1β, IL-6 and TNF-α. Blocking of Gα_s by NF449 resulted in a loss of this anti-inflammatory effect in BV-2 cells. Analyses in signaling pathways demonstrated that GLP-2 reduced LPS-induced phosphorylation of ERK1/2, JNK1/2 and p65, while no effect was observed on p38 phosphorylation. In addition, GLP-2 could suppress microglia-mediated neurotoxicity. All results imply that GLP-2 inhibits LPS-induced microglia activation by collectively regulating ERK1/2, JNK1/2 and p65.     

Hypoxic Conditioned Medium from Human Amniotic Fluid-Derived Mesenchymal Stem Cells Accelerates Skin Wound Healing through TGF-β/SMAD2 and PI3K/Akt Pathways

In a previous study, we isolated human amniotic fluid (AF)-derived mesenchymal stem cells (AF-MSCs) and utilized normoxic conditioned medium (AF-MSC-norCM) which has been shown to accelerate cutaneous wound healing. Because hypoxia enhances the wound healing function of mesenchymal stem cell-conditioned medium (MSC-CM), it is interesting to explore the mechanism responsible for the enhancement of wound healing function. In this work, hypoxia not only increased the proliferation of AF-MSCs but also maintained their constitutive characteristics (surface marker expression and differentiation potentials). Notably, more paracrine factors, VEGF and TGF-β1, were secreted into hypoxic conditioned medium from AF-MSCs (AF-MSC-hypoCM) compared to AF-MSC-norCM. Moreover, AF-MSC-hypoCM enhanced the proliferation and migration of human dermal fibroblasts in vitro, and wound closure in a skin injury model, as compared to AF-MSC-norCM. However, the enhancement of migration of fibroblasts accelerated by AF-MSC-hypoCM was inhibited by SB505124 and {"type":"entrez-nucleotide","attrs":{"text":"LY294002","term_id":"1257998346","term_text":"LY294002"}}LY294002, inhibitors of TGF-β/SMAD2 and PI3K/AKT, suggesting that AF-MSC-hypoCM-enhanced wound healing is mediated by the activation of TGF-β/SMAD2 and PI3K/AKT. Therefore, AF-MSC-hypoCM enhances wound healing through the increase of hypoxia-induced paracrine factors via activation of TGF-β/SMAD2 and PI3K/AKT pathways.     

Shikonin Inhibits the Migration and Invasion of Human Glioblastoma Cells by Targeting Phosphorylated β-Catenin and Phosphorylated PI3K/Akt: A Potential Mechanism for the Anti-Glioma Efficacy of a Traditional Chinese Herbal Medicine

Shikonin is an anthraquinone derivative extracted from the root of lithospermum. Shikonin is traditionally used in the treatment of inflammatory and infectious diseases such as hepatitis. Shikonin also inhibits proliferation and induces apoptosis in various tumors. However, the effect of shikonin on gliomas has not been fully elucidated. In the present study, we aimed to investigate the effects of shikonin on the migration and invasion of human glioblastoma cells as well as the underlying mechanisms. U87 and U251 human glioblastoma cells were treated with shikonin at 2.5, 5, and 7.5 μmol/L and cell viability, migration and invasiveness were assessed with CCK8, scratch wound healing, in vitro Transwell migration, and invasion assays. The expression and activity of matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) and the expression of phosphorylated β-catenin (p-β-catenin) and phosphorylated PI3K/Akt were also checked. Results showed that shikonin significantly inhibited the cell proliferation, migration, invasion, and expression of MMP-2 and MMP-9 in U87 and U251 cells. The expression of p-β-catenin showed contrary trends in two cell lines. It was significantly inhibited in U87 cells and promoted in U251 cells. Results in this work indicated that shikonin displayed an inhibitory effect on the migration and invasion of glioma cells by inhibiting the expression and activity of MMP-2 and -9. In addition, shikonin also inhibited the expression of p-PI3K and p-Akt to attenuate cell migration and invasion and MMP-2 and MMP-9 expression in both cell lines, which could be reversed by the PI3K/Akt pathway agonist, insulin-like growth factor-1 (IGF-1).     

Sinomenine Derivatives: Synthesis,Antitumor Activity,and Apoptotic Induction in MCF-7 Cells via IL-6/PI3K/Akt/NF-κB Signaling Pathway

Natural products have been widely considered as an important resource for new drugs or lead compounds. Sinomenine (SIN) and its derivatives exert antitumor activity via regulation of inflammatory mediators. For these reasons we synthesized three series of SIN derivatives (compounds 4 a – i , 7 a – c and 11 a – c ) as antitumor agents from this natural product. All compounds were prepared by modification at the C1 and C4 positions of the A ring, the C4 position of the A ring, and the C6 and C7 positions of the C ring, respectively. All the derivatives were subjected to in vitro antitumor activity against HeLa, A549, HepG-2, MCF-7 and HT-29 cell lines. To observe the apoptotic induction of SIN derivatives and its mechanism, fluorescent staining and western blot assays were carried out for active compound against MCF-7. Based on the screening results, most of the SIN derivatives showed better antitumor activity than SIN. Some of them were found to possess broad-spectrum antitumor activity. Most notably, 11 c exhibited obvious antitumor activity in both cell lines with IC₅₀ values less than 11 μM. Besides, 11 c induced apoptosis of MCF-7 in a dose-dependent manner. Western blot assay demonstrated that 11 c inhibited IL-6-mediated activation of PI3K/Akt pathway. A docking study revealed that 11 c had stronger binding interaction with the residues of IL-6 than SIN. All these results indicate that 11 c may be a potential anti-breast cancer agent by directly targeting IL-6.     

Modulation of the PI3K/Akt Pathway and Bcl-2 Family Proteins Involved in Chicken’s Tubular Apoptosis Induced by Nickel Chloride (NiCl2)

Exposure of people and animals to environments highly polluted with nickel (Ni) can cause pathologic effects. Ni compounds can induce apoptosis, but the mechanism and the pathway of Ni compounds-induced apoptosis are unclear. We evaluated the alterations of apoptosis, mitochondrial membrane potential (MMP), phosphoinositide-3-kinase (PI3K)/serine-threonine kinase (Akt) pathway, and Bcl-2 family proteins induced by nickel chloride (NiCl₂) in the kidneys of broiler chickens, using flow cytometry, terminal deoxynucleotidyl transferase 2ʹ-deoxyuridine 5ʹ-triphosphate dUTP nick end-labeling (TUNEL), immunohistochemstry and quantitative real-time polymerase chain reaction (qRT-PCR). We found that dietary NiCl₂ in excess of 300 mg/kg resulted in a significant increase in apoptosis, which was associated with decrease in MMP, and increase in apoptosis inducing factor (AIF) and endonuclease G (EndoG) protein and mRNA expression. Concurrently, NiCl₂ inhibited the PI3K/Akt pathway, which was characterized by decreasing PI3K, Akt1 and Akt2 mRNA expression levels. NiCl₂ also reduced the protein and mRNA expression of anti-apoptotic Bcl-2 and Bcl-xL and increased the protein and mRNA expression of pro-apoptotic Bax and Bak. These results show that NiCl₂ causes mitochondrial-mediated apoptosis by disruption of MMP and increased expression of AIF and EndoG mRNA and protein, and that the underlying mechanism of MMP loss involves the Bcl-2 family proteins modulation and PI3K/Akt pathway inhibition.