Bisphenol A modulates colorectal cancer protein profile and promotes the metastasis via induction of epithelial to mesenchymal transitions.

More and more evidences indicate that endocrine disruptor chemicals such as bisphenol A (BPA) can act as carcinogens and enhance susceptibility to tumorigenesis. Although the gut is in direct contact with orally ingested BPA, effects of BPA on occurrence and development of colorectal cancer remain an unexplored endpoint. Colorectal cancer SW480 cells treated with nanomolar (10(-8) M) or greater (10(-5) M) concentrations of BPA were compared with responses of a control group. Proteomic study revealed that more than 56 proteins were modulated following exposure to BPA, which are relevant to structure, motility and proliferation of cells, production of ATP, oxidative stress, and protein metabolism. Further studies revealed that BPA increased migration and invasion and triggered transformations from epithelial to mesenchymal transitions (EMTs) of colorectal cancer cells, which was characterized by acquiring mesenchymal spindle-like morphology and increasing the expression of N-cadherin with a concomitant decrease of E-cadherin. Accordingly, BPA treatment increased the expression of transcription factor Snail. Furthermore, signal AKT/GSK-3ß-mediated stabilization of Snail is involved during BPA-induced EMT of colon cancer cells. Our study first demonstrated that the xenoestrogen BPA at nanomolar and greater concentrations modulates the protein profiles and promotes the metastasis of colorectal cancer cells via induction of EMT.

Exploring the chemodiversity and biological activities of the secondary metabolites from the marine fungus Neosartorya pseudofischeri.

The production of fungal metabolites can be remarkably influenced by various cultivation parameters. To explore the biosynthetic potentials of the marine fungus, Neosartorya pseudofischeri, which was isolated from the inner tissue of starfish Acanthaster planci, glycerol-peptone-yeast extract (GlyPY) and glucose-peptone-yeast extract (GluPY) media were used to culture this fungus. When cultured in GlyPY medium, this fungus produced two novel diketopiperazines, neosartins A and B (1 and 2), together with six biogenetically-related known diketopiperazines,1,2,3,4-tetrahydro-2, 3-dimethyl-1,4-dioxopyrazino[1,2-a]indole (3), 1,2,3,4-tetrahydro-2-methyl-3-methylen e-1,4-dioxopyrazino[1,2-a]indole (4), 1,2,3,4-tetrahydro-2-methyl-1,3,4-trioxopyrazino[1,2-a] indole (5), 6-acetylbis(methylthio)gliotoxin (10), bisdethiobis(methylthio)gliotoxin (11), didehydrobisdethiobis(methylthio)gliotoxin (12) and N-methyl-1H-indole-2-carboxamide (6). However, a novel tetracyclic-fused alkaloid, neosartin C (14), a meroterpenoid, pyripyropene A (15), gliotoxin (7) and five known gliotoxin analogues, acetylgliotoxin (8), reduced gliotoxin (9), 6-acetylbis(methylthio)gliotoxin (10), bisdethiobis(methylthio) gliotoxin (11) and bis-N-norgliovictin (13), were obtained when grown in glucose-containing medium (GluPY medium). This is the first report of compounds 3, 4, 6, 9, 10 and 12 as naturally occurring. Their structures were determined mainly by MS, 1D and 2D NMR data. The possible biosynthetic pathways of gliotoxin-related analogues and neosartin C were proposed. The antibacterial activity of compounds 2-14 and the cytotoxic activity of compounds 4, 5 and 7-13 were evaluated. Their structure-activity relationships are also preliminarily discussed.

Activation of NMDA receptors upregulates a disintegrin and metalloproteinase 10 via a Wnt/MAPK signaling pathway.

A disintegrin and metalloproteinase 10 (ADAM10) is the constitutive α-secretase that governs the nonamyloidogenic pathway of ß-amyloid precursor protein processing and is an attractive drug target for treating Alzheimer's disease. To date, little is known about the mechanism by which ADAM10 is regulated in neurons. Using mouse primary cortical neurons, we show here that NMDA receptor (NMDAR) activation led to upregulation of the genes encoding ADAM10 and ß-catenin proteins. Interestingly, the ADAM10 upregulation was abolished by inhibitors of Wnt/ß-catenin signaling. Conversely, activation of the Wnt/ß-catenin signaling pathway by recombinant Wnt3a stimulated ADAM10 expression. We further showed that both the NMDAR- and Wnt3a-induced ADAM10 upregulation was blocked by ERK inhibitors. We suggest that the NMDARs control ADAM10 expression via a Wnt/MAPK signaling pathway.

Effects of conjugated linoleic acid on cleavage of amyloid precursor protein via PPARγ.

Conjugated linoleic acid (CLA) plays important roles in physiological conditions. The aim of present study was to explore the effects of CLA on the cleavage of amyloid precursor protein (APP) and the potential mechanism involved. The effects of CLA on intracellular APP, BACE1 (ß-site APP Cleaving Enzyme1, BACE1), a disintegrin and metalloprotease (ADAM10) and extracellular sAPPα (soluble) were analyzed by RT-PCR, Western blot and ELISA in SH-SY5Y cells. Our study indicated that CLA significantly decreased the expression of BACE1 and increased the extracellular secretion of sAPPα, but not affected the levels of APP and ADAM10. The study also revealed that the nuclear receptor peroxisome proliferators activated receptor γ (PPARγ) played an important role in the CLA-induced intracellular BACE1 decrease, as well as the extracellular sAPPα increase through knockdown of PPARγ transcription using siRNA. We hypothesize that CLA acts as an agonist or ligand, which binds with PPARγ and leads to the increase in APP cleavage via α-secretase-mediated pathway and the decrease in the deposition of Aß.

Inhibition of ERRα suppresses epithelial mesenchymal transition of triple negative breast cancer cells by directly targeting fibronectin.

Triple-negative breast cancer (TNBC) patients have poor prognosis due to the aggressive metastatic behaviors. Our study reveals that expression of estrogen related receptor α (ERRα) is significantly (p < 0.01) positively associated with high grade tumors and lymph node metastasis, while negatively correlated with overall survival (OS), in 138 TNBC patients. Targeted inhibition of ERRα by its inverse agonist XCT-790 or si-RNA obviously inhibits in vitro motility of TNBC cells. While over expression of ERRα triggers the invasion and migration of TNBC cells. Further, si-ERRα and XCT-790 inhibit the epithelial mesenchymal transition (EMT) of TNBC cells with increasing the expression of E-cadherin and decreasing fibronectin (FN) and vimentin. While XCT-790 has no effect on the expression of EMT related transcription factors such as Snail or Slug. Further, inhibitors of MAPK, PI3K/Akt, NF-κB signal molecules, which are activated by XCT-790, can not attenuate the suppression effects of XCT-790 on EMT. Alternatively, luciferase reporter gene assays and ChIP analysis indicate that ERRα can directly bind with FN promoter at ERR response element-3 (ERRE-1), ERRE-3, and ERRE-4, while XCT-790 reduces this bond. In vivo data show that ERRα expression is significantly (p < 0.05) correlated with FN in clinical TNBC patients. In MDA-MB-231 tumor xenograft models, XCT-790 decreases the expression of FN, inhibits the growth and lung metastasis, and suppresses the EMT. Our results demonstrate that ERRα functions as a metastasis stimulator and its targeted inhibition may be a new therapeutic strategy for TNBC treatment.

A novel micro-linear vector for in vitro and in vivo gene delivery and its application for EBV positive tumors.

BACKGROUND: The gene delivery vector for DNA-based therapy should ensure its transfection efficiency and safety for clinical application. The Micro-Linear vector (MiLV) was developed to improve the limitations of traditional vectors such as viral vectors and plasmids. METHODS: The MiLV which contained only the gene expression cassette was amplified by polymerase chain reaction (PCR). Its cytotoxicity, transfection efficiency in vitro and in vivo, duration of expression, pro-inflammatory responses and potential application for Epstein-Barr virus (EBV) positive tumors were evaluated. RESULTS: Transfection efficiency for exogenous genes transferred by MiLV was at least comparable with or even greater than their corresponding plasmids in eukaryotic cell lines. MiLV elevated the expression and prolonged the duration of genes in vitro and in vivo when compared with that of the plasmid. The in vivo pro-inflammatory response of MiLV group was lower than that of the plasmid group. The MEKK1 gene transferred by MiLV significantly elevated the sensitivity of B95-8 cells and transplanted tumor to the treatment of Ganciclovir (GCV) and sodium butyrate (NaB). CONCLUSIONS: The present study provides a safer, more efficient and stable MiLV gene delivery vector than plasmid. These advantages encourage further development and the preferential use of this novel vector type for clinical gene therapy studies.