The catalytically defective receptor protein tyrosine kinase EphA10 promotes tumorigenesis in pancreatic cancer cells.

EphA10 (erythropoietin-producing hepatocellular carcinoma receptor A10) is a catalytically defective receptor protein tyrosine kinase in the ephrin receptor family. Although EphA10 is involved in the malignancy of some types of cancer, its role as an oncogene has not been extensively studied. Here, we investigated the influence of EphA10 on the tumorigenic potential of pancreatic cancer cells. Analysis of expression profiles from The Cancer Genome Atlas confirmed that EphA10 was elevated and higher in tumor tissues than in normal tissues in some cancer types, including pancreatic cancer. EphA10 silencing reduced the proliferation, migration, and adhesion of MIA PaCa-2 and AsPC-1 pancreatic cancer cells. These effects were reversed by overexpression of EphA10 in MIA PaCa-2 cells. Importantly, overexpression and silencing of EphA10 respectively increased and decreased the weight, volume, and number of Ki-67-positive proliferating cells in MIA PaCa-2 xenograft tumors. Further, EphA10 expression was positively correlated with invasion and gelatin degradation in MIA PaCa-2 cells. Moreover, overexpression of EphA10 enhanced the expression and secretion of MMP-9 in MIA PaCa-2 cells and increased the expression of MMP-9 and the vascular density in xenograft tumors. Finally, expression of EphA10 increased the phosphorylation of ERK, JNK, AKT, FAK, and NF-κB, which are important for cell proliferation, survival, adhesion, migration, and invasion. Therefore, we suggest that EphA10 plays a pivotal role in the tumorigenesis of pancreatic epithelial cells and is a novel therapeutic target for pancreatic cancer.

Synthesis and Characterization of Co-Mn (O)OH Nanosheets Assembled Structure Covered of Reduced Graphene Oxide Hybrid Structures by Hydrothermal Method.

In this study, we prepared cobalt-manganese (oxy) hydroxide nanosheets assembled structure covered of reduced graphene oxide hybrid structure (Co-Mn (O)OH NAS@rGO HS) via reduction and hydroxylation of Mn1.5Co1.5[Co(CN)6]2@graphene oxide (GO). Obtained precursors were optimized at 15 mg GO, and these are hybrid structures in which nanocubes 200-400 nm in size were fully covered by multi-layered GO. The functional group (-COOH, -OH, C-O-C) of GO was removed through reduction by L-ascorbic acid. We obtained MnCOOH, Co(OH)2, and Co-Mn LDH synthesized by hydroxylation of Mn1.5Co1.5[Co(CN)6]2@GO via ion exchange between the CN group and OH-. The hybrid nanostructure between transition-metal oxide/hydroxide and reduced graphene oxide could be used in various fields, including lithium ion batteries, supercapacitors, and electrocatalyst for water splitting.

Skullcapflavone II Inhibits Degradation of Type I Collagen by Suppressing MMP-1 Transcription in Human Skin Fibroblasts.

Skullcapflavone II is a flavonoid derived from the root of Scutellaria baicalensis, a herbal medicine used for anti-inflammatory and anti-cancer therapies. We analyzed the effect of skullcapflavone II on the expression of matrix metalloproteinase-1 (MMP-1) and integrity of type I collagen in foreskin fibroblasts. Skullcapflavone II did not affect the secretion of type I collagen but reduced the secretion of MMP-1 in a dose- and time-dependent manner. Real-time reverse transcription-PCR and reporter gene assays showed that skullcapflavone II reduced MMP-1 expression at the transcriptional level. Skullcapflavone II inhibited the serum-induced activation of the extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) signaling pathways required for MMP-1 transactivation. Skullcapflavone II also reduced tumor necrosis factor (TNF)-α-induced nuclear factor kappa light chain enhancer of activated B cells (NF-κB) activation and subsequent MMP-1 expression. In three-dimensional culture of fibroblasts, skullcapflavone II down-regulated TNF-α-induced MMP-1 secretion and reduced breakdown of type I collagen. These results indicate that skullcapflavone II is a novel biomolecule that down-regulates MMP-1 expression in foreskin fibroblasts and therefore could be useful in therapies for maintaining the integrity of extracellular matrix.

Syndecan-2 cytoplasmic domain up-regulates matrix metalloproteinase-7 expression via the protein kinase Cγ-mediated FAK/ERK signaling pathway in colon cancer.

The syndecan family of heparan sulfate proteoglycans contributes to cell adhesion and communication by serving as co-receptors for cell signaling and extracellular matrix molecules. Syndecan-2 is located at the cell surface, and we previously reported that it induces matrix metalloproteinase-7 (MMP-7) expression in colon cancer cells. However, the underlying regulatory mechanisms are unknown. Here, we report that overexpression of syndecan-2 in HT-29 colon cancer cells increases the phosphorylation of focal adhesion kinase (FAK) and ERK in parallel with up-regulated MMP-7 expression, but a syndecan-2 mutant lacking the cytoplasmic domain showed significant reductions in these effects. Consistent with this observation, FAK inhibition via FAK-related non-kinase expression or inhibition of ERK with the ERK1/2 inhibitor SCH772984 diminished the syndecan-2-mediated up-regulation of MMP-7. Activation of PKC enhanced syndecan-2-mediated MMP-7 expression, whereas inhibition of PKC had the opposite effect. Of note, the exogenous expression of syndecan-2 triggered localization of PKCγ to the membrane. Expression of syndecan-2 harboring a phosphomimetic (S198E) mutation of the variable region of the cytoplasmic domain enhanced MMP-7 expression and FAK phosphorylation. Finally, experimental suppression of shedding of the syndecan-2 extracellular domain did not significantly affect the syndecan-2-mediated up-regulation of MMP-7 in the early period after syndecan-2 overexpression. Taken together, these findings suggest that syndecan-2's cytoplasmic domain up-regulates MMP-7 expression in colon cancer cells via PKCγ-mediated activation of FAK/ERK signaling.

Processing of syndecan-2 by matrix metalloproteinase-14 and effect of its cleavage on VEGF-induced tube formation of HUVECs.

Syndecans (SDCs) are transmembrane proteoglycans that are involved in cell adhesion and cell communication. Specifically, SDC2 plays a key role in tumorigenesis, metastasis, and angiogenesis. Previously, we found that rat SDC2 is shed by matrix metalloproteinase-7 (MMP-7) in colon cancer cells. Here, we analyzed the susceptibility of rat SDC2 to various MMPs. We found that the rat SDC2 ectodomain (ECD) fused to the C-terminal Fc region, which was expressed in mammalian cells, was cleaved more efficiently by MMP-14 than MMP-7. Likewise, when anchored on the surface of HeLa cells, rat SDC2 was cleaved more efficiently by the treatment of MMP-14 than MMP-7 and was shed more readily by membrane-anchored MMP-14 than soluble MMP-14. Furthermore, MMP-14 cleaved recombinant SDC2-ECD expressed in Escherichia coli into multiple fragments. Using N-terminal amino acid sequencing and the top-down proteomics approach, we determined that the major cleavage sites were S88↓L89, T98↓M99, T100↓L101, D132↓P133, and N148↓L149 for rat SDC2-ECD and S55↓G56, S65↓P66, P75↓K76, N92↓I93 D122↓P123, and S138↓L139 for human SDC2-ECD. Finally, the rat and human SDC2-ECD lost the ability to suppress vascular endothelial growth factor-induced formation of capillary-like tubes by human umbilical vein endothelial cells following cleavage by MMP-14, but its major cleavage-site mutant of rat SDC2-ECD did not. These results suggest that MMP-14 is a novel enzyme responsible for degrading SDC2 and impairing its physiological roles including angiogenesis.

Epiregulin Recognition Mechanisms by Anti-epiregulin Antibody 9E5: STRUCTURAL, FUNCTIONAL, AND MOLECULAR DYNAMICS SIMULATION ANALYSES.

Epiregulin (EPR) is a ligand of the epidermal growth factor (EGF) family that upon binding to its epidermal growth factor receptor (EGFR) stimulates proliferative signaling, especially in colon cancer cells. Here, we describe the three-dimensional structure of the EPR antibody (the 9E5(Fab) fragment) in the presence and absence of EPR. Among the six complementarity-determining regions (CDRs), CDR1-3 in the light chain and CDR2 in the heavy chain predominantly recognize EPR. In particular, CDR3 in the heavy chain dramatically moves with cis-trans isomerization of Pro(103). A molecular dynamics simulation and mutational analyses revealed that Arg(40) in EPR is a key residue for the specific binding of 9E5 IgG. From isothermal titration calorimetry analysis, the dissociation constant was determined to be 6.5 nm. Surface plasmon resonance analysis revealed that the dissociation rate of 9E5 IgG is extremely slow. The superimposed structure of 9E5(Fab)·EPR on the known complex structure of EGF·EGFR showed that the 9E5(Fab) paratope overlaps with Domains I and III on the EGFR, which reveals that the 9E5(Fab)·EPR complex could not bind to the EGFR. The 9E5 antibody will also be useful in medicine as a neutralizing antibody specific for colon cancer.

PTK6 Localized at the Plasma Membrane Promotes Cell Proliferation and MigratiOn Through Phosphorylation of Eps8.

Protein tyrosine kinase 6 (PTK6; also known as Brk) is closely related to the Src family kinases, but lacks a membrane-targeting myristoylation signal. Sublocalization of PTK6 at the plasma membrane enhances its oncogenic potential. To understand the mechanism(s) underlying the oncogenic property of plasma---membrane-associated PTK6, proteins phosphorylated by membrane-targeted myristoylated PTK6 (Myr-PTK6) were enriched and analyzed using a proteomics approach. Eps8 which was identified by this method is phosphorylated by Myr-PTK6 in HEK293 cells. Mouse Eps8 expressed in HEK293 cells is phosphorylated by Myr-PTK6 at residues Tyr497, Tyr524, and Tyr534. Compared to wild-type Eps8 (Eps8 WT), the phosphorylation-defective 3YF mutant (Eps8 3YF) reverts the increased proliferation, migration, and phosphorylation of ERK and FAK mediated by Eps8 WT in HEK293 cells overexpressing PTK6. PTK6 knockdown in T-47D breast cancer cells decreased EGF-induced phosphorylation of Eps8. Endogenous PTK6 phosphorylates ectopically expressed Eps8 WT, but not Eps8 3YF mutant, in EGF-stimulated T-47D cells. The EGF-induced Eps8 phosphorylation enhances activation of ERK and FAK, cell adhesion, and anchorage-independent colony formation in T-47D cells, but not in the PTK6-knokdown T-47D cells. These results indicate that plasma-membrane-associated PTK6 phosphorylates Eps8, which promotes cell proliferation, adhesion, and migration and, thus, tumorigenesis. J. Cell. Biochem. 118: 2887-2895, 2017. © 2017 Wiley Periodicals, Inc.

Synthesis of novel flavone derivatives possessing substituted benzamides and their biological evaluation against human cancer cells.

Baicalein is a well-known flavone derivative that possesses diverse biological properties, such as anticancer, antioxidant and anti-inflammatory activities. Numerous baicalein derivatives, including 5,6,7-trimethoxyflavone, have been synthesized with the aim of enhancing its inherent biological activities. In the present work, new flavones, possessing an N-aroylamine-substituent on the B-ring, were synthesized to improve the cytotoxicity of baicalein and 5,6,7-trimethoxyflavone against human cancer cell lines. The majority of the flavones synthesized exhibited greater cytotoxicity than baicalein and 5,6,7-trimethoxyflavone against HepG2 and MCF-7 cells. Among them, compounds 5n, possessing a 3-methoxybenzoylamino group, exhibited great cytotoxic effects on HepG2 (GI50=7.06µM) and MCF-7 (GI50=7.67µM) cells. In contrast, N-aroylamine-substituted 5-hydroxy-6,7-dimethoxyflavone derivatives showed greater cytotoxicity against MCF-7 than HepG2 cells, indicating that the replacement of a 5-methoxy group on the A-ring with a 5-hydroxy group has a marked influence on the cytotoxicity profile.

Synthesis and biological evaluation of 1,2-dithiol-3-thiones and pyrrolo[1,2-a]pyrazines as novel hypoxia inducible factor-1 (HIF-1) inhibitor.

Hypoxia-inducible factor-1 (HIF-1) is a key transcription factor which is strongly associated with tumor survival, progression, and therapeutic resistance. Accordingly, it has been suggested that the inhibition of the HIF-1 pathway can suppress tumor, and it has become an important therapeutic target. In present study, oltipraz, its metabolite M2, and their derivatives were synthesized and evaluated as HIF-1α inhibitors. Among the synthesized, benzyl-substituted pyrrolo[1,2-a]pyrazine 2g most potently inhibited HIF-1α protein accumulation (81% at 10µM) and VEGF, GLUT-1 transcription (77% and 92% at 10µM, respectively).

Synthesis of (2-amino)ethyl derivatives of quercetin 3-O-methyl ether and their antioxidant and neuroprotective effects.

Reactive oxygen species have been implicated in several diseases, particularly in ischemia-reperfusion injury. Quercetin 3-O-methyl ether has been reported to show potent antioxidant and neuroprotective activity against neuronal damage induced by reactive oxygen species. Several aminoethyl-substituted derivatives of quercetin 3-O-methyl ether have been synthesized to increase water solubility while retaining antioxidant and neuroprotective activity. Among such derivatives, compound 3a shows potent and well-balanced antioxidant activity in three types of cell-free assay systems and has in vivo neuroprotective effects on transient focal ischemic injury induced by the occlusion of the middle cerebral artery in rats.

Synthesis of aminoalkyl-substituted aurone derivatives as acetylcholinesterase inhibitors.

Alzheimer's disease (AD), a progressive and neurodegenerative disorder of the brain, is the most common cause of dementia among elderly people. To date, the successful therapeutic strategy to treat AD is maintaining the levels of acetylcholine by inhibiting acetylcholinesterase (AChE). In the present study, aurone derivatives were designed and synthesized as AChE inhibitors based on the lead structure of sulfuretin. Of those synthesized, compound 10d showed ca. 1700-fold and 6-fold higher AChE inhibitory activity than sulfuretin and galantamine, respectively. This compound also ameliorated scopolamine-induced memory deficit in mice when administered orally at the dose of 1 and 2mg/kg.

Synthesis of aminoalkyl-substituted coumarin derivatives as acetylcholinesterase inhibitors.

Alzheimer's disease, one of the most common forms of dementia, is a progressive neurodegenerative disorder symptomatically characterized by declines in memory and cognitive abilities. To date, the successful therapeutic strategy to treat AD is maintaining levels of acetylcholine by inhibiting acetylcholinesterase (AChE). In the present study, coumarin derivatives were designed and synthesized as AChE inhibitors based on the lead structure of scopoletin. Of those synthesized, pyrrolidine-substituted coumarins 3b and 3f showed ca. 160-fold higher AChE inhibitory activities than scopoletin. These compounds also ameliorated scopolamine-induced memory deficit in mice when administered orally at the dose of 1 and 2 mg/kg.

The presence of outer arm fucose residues on the N-glycans of tissue inhibitor of metalloproteinases-1 reduces its activity.

Tissue inhibitor of metalloproteinases-1 (TIMP-1) inhibits matrix metalloproteinases (MMPs) by binding at a 1:1 stoichiometry. Here we have shown the involvement of N-glycosylation in the MMP inhibitory ability of TIMP-1. TIMP-1, purified from HEK 293 cells overexpressing TIMP-1 (293 TIMP-1), showed less binding and inhibitory abilities to MMPs than TIMP-1 purified from fibroblasts or SF9 insect cells infected with TIMP-1 baculovirus. Following deglycosylation of TIMP-1, all forms of TIMP-1 showed similar levels of MMP binding and inhibition, suggesting that glycosylation is involved in the regulation of these TIMP-1 activities. Analysis of the N-glycan structures showed that SF9 TIMP-1 has the simplest N-glycan structures, followed by fibroblast TIMP-1 and 293 TIMP-1, in order of increasing complexity in their N-glycan structures. Further analyses showed that cleavage of outer arm fucose residues from the N-glycans of 293 TIMP-1 or knockdown of both FUT4 and FUT7 (which encode for fucosyltransferases that add outer arm fucose residues to N-glycans) enhanced the MMP-binding and catalytic abilities of 293 TIMP-1, bringing them up to the levels of the other TIMP-1. These results demonstrate that the ability of TIMP-1 to inhibit MMPs is at least in part regulated by outer arm fucosylation of its N-glycans.

Construction and characterization of functional anti-epiregulin humanized monoclonal antibodies.

Growth factors are implicated in several processes essential for cancer progression. Specifically, epidermal growth factor (EGF) family members, including epiregulin (EREG), are important prognostic factors in many epithelial cancers, and treatments targeting these molecules have recently become available. Here, we constructed and expressed humanized anti-EREG antibodies by variable domain resurfacing based on the three-dimensional (3D) structure of the Fv fragment. However, the initial humanized antibody (HM0) had significantly decreased antigen-binding affinity. Molecular modeling results suggested that framework region (FR) residues latently important to antigen binding included residue 49 of the light chain variable region (VL). Back mutation of the VL49 residue (tyrosine to histidine) generated the humanized version HM1, which completely restored the binding affinity of its murine counterpart. Importantly, only one mutation in the framework may be necessary to recover the binding capability of a humanized antibody. Our data support that HM1 exerts potent antibody-dependent cellular cytotoxicity (ADCC). Hence, this antibody may have potential for further development as a candidate therapeutic agent and research tool.

Synthesis of indolyl-3-acetonitrile derivatives and their inhibitory effects on nitric oxide and PGE2 productions in LPS-induced RAW 264.7 cells.

Arvelexin is one of major constituents of Brassica rapa that exerts anti-inflammatory activities. Several indolyl-3-acetonitrile derivatives were synthesized as arvelexin analogs and evaluated for their abilities to inhibit NO and PGE2 productions in LPS-induced RAW 264.7 cells. Of the indolyl-3-acetonitriles synthesized, compound 2k, which possesses a hydroxyl group at C-7 position of the indole ring and an N-methyl substituent, more potently inhibited NO and PGE2 productions and was less cytotoxic than arvelexin on macrophage cells.

Hypoxia-inducible factor-1α inhibition by a pyrrolopyrazine metabolite of oltipraz as a consequence of microRNAs 199a-5p and 20a induction.

Oltipraz, a cancer chemopreventive agent, has antitumor and antiangiogenic effects. In animal models and clinical studies, a considerable amount of oltipraz is metabolized to pyrrolopyrazines, including M2, 7-methyl-6,8-bis(methylthio)pyrrolo[1,2-a]pyrazine; M3, 7-methyl-8-(methylsulfinyl)-6-(methylthio)pyrrolo[1,2-a]pyrazine and M4, 7-methyl-6,8-bis(methylsulfinyl)pyrrolo[1,2-a]pyrazine. In view of the role of hypoxia-inducible factor-1 (HIF-1) α in tumor growth and angiogenesis, this study investigated whether pyrrolopyrazine metabolites of oltipraz inhibit HIF-1α induction, and if so, what the molecular basis is. M2 treatment inhibited the induction of HIF-1α by a variety of stimuli including insulin, hypoxia, CoCl(2) and hydrogen peroxide in HCT116 cells, whereas M3 or M4 failed to do so. Consistently, M2 prevented HIF-1α target gene induction. Moreover, it inhibited cancer cell invasion and migration. M2 caused no change in the expression of HIF-1α transcript but increased the levels of precursor forms of microRNAs (miRNAs) 199a-5p and 20a, but not those of primary forms, indicating facilitation of the maturation process of the miRNAs by M2. Increased levels of the miRNAs contributed to HIF-1α repression, as shown by the results of experiments using mimics. Consistently, M2 treatment inhibited de novo synthesis of HIF-1α, as supported by decreased incorporation of [(35)S]-methionine into HIF-1α with no changes in its ubiquitination or degradation. 7-Ethyl-6,8-bis(methylthio)pyrrolo[1,2-a]pyrazine, a synthetic analog of M2, had a similar inhibitory effect. In conclusion, M2 with pyrrolopyrazine structure and its 7-ethyl congenor have the ability to prevent the induction of HIF-1α, which may result from the inhibition of HIF-1α de novo synthesis, as mediated by the induction of miR-199a-5p and miR-20a.

Significant enhancement of the power conversion efficiency for organic photovoltaic cells due to a P3HT pillar layer containing ZnSe quantum dots.

High-efficiency organic photovoltaic (OPV) cells utilizing a poly(3-hexylthiophene) (P3HT) pillar layer containing ZnSe quantum dots (QDs) were fabricated by using a mixed solution method. Scanning electron microscopy and high-resolution transmission electron microscopy images showed that the ZnSe QDs were dispersed in the P3HT layer. The power conversion efficiency of the OPV cells with a P3HT pillar layer containing ZnSe QDs was as much as 100% higher than that of the OPV cells with a planar layer due to an enhancement of the photon-harvesting ability of the congregated P3HT particles containing ZnSe QDs and to an increase of the interfacial region for efficient charge transport.

4'-bromo-5,6,7-trimethoxyflavone represses lipopolysaccharide-induced iNOS and COX-2 expressions by suppressing the NF-κB signaling pathway in RAW 264.7 macrophages.

The regulations of the NO and PGE(2) productions are research topics of interest in the field of anti-inflammatory drug development. In the present study, 5,6,7-trimethoxy- and 5,6,7-trihydroxyflavones 3a-3g were synthesized from cinnamic acid derivatives. In particular, 4'-bromo-5,6,7-trimethoxyflavone (3b) most potently inhibited the productions of NO and PGE(2) in LPS-treated RAW 264.7 cells (IC(50)=14.22 ± 1.25 and 10.98 ± 6.25 µM, respectively), and these inhibitory effects were more potent than those of oroxylin A or baicalein. Consistent with these findings, 3b concentration-dependently reduced the LPS-induced expressions of iNOS and COX-2 at the protein and mRNA levels. In addition, the release of TNF-α, IL-6, and IL-1ß and the mRNA expressions of these cytokines were reduced by 3b in a concentration-dependent manner. Furthermore, 3b attenuated the LPS-induced transcriptional activities of NF-κB and this was accompanied by parallel reductions in the degradation and phosphorylation of IκB-α, and consequently by a decrease in the nuclear translocation of the p65 subunit of NF-κB. Taken together, these results suggest that suppressions of the expressions of iNOS, COX-2, TNF-α, IL-6, and IL-1ß via NF-κB inactivation are responsible for the anti-inflammatory effects of 3b.

Controlled Synthesis of Metal-Organic Frameworks in Scalable Open-Porous Contactor for Maximizing Carbon Capture Efficiency.

Metal-organic frameworks (MOFs) are a class of microporous materials that have been highlighted with fast and selective sorption of gas molecules; however, they are at least partially unstable in the scale-up process. Here, we report a rational shaping of MOFs in a scalable architecture of fiber sorbent. The long-standing stability challenge of MOFs was resolved by using stable metal oxide precursors that are subject to controlled surface oxide dissolution-growth chemistry during the Mg-based MOF synthesis. Highly uniform MOF crystals are synthesized along with the open-porous fiber sorbents networks, showing unprecedented cyclic CO2 capacities in both flue gas and direct air capture (DAC) conditions. The same chemistry enables an in situ flow synthesis of Mg-MOF fiber sorbents, providing a scalable pathway for MOF synthesis in an inert condition with minimal handling steps. This modular approach can serve both as a reaction stage for enhanced MOF fiber sorbent synthesis and as a "process-ready" separation device.

A Study on Optimal Machining Conditions and Energy Efficiency in Plasma Assisted Machining of Ti-6Al-4V.

This research objective was to determine the significant parameters for effective plasma assisted machining (PAM) of Ti-6Al-4V and to derive optimal processing conditions. PAM parameters such as feed rate, spindle speed, and depth of cut have significant effects on its machining characteristic. In this study, the design of experiments (DOE) was used to select optimal machining conditions for PAM. The signal-to-noise (S/N) ratio was analyzed using the Taguchi method and the contributions of the factors were determined using analysis of variance (ANOVA). Finally, the optimal PAM machining conditions were selected using response optimization. In addition, the energy efficiency of conventional machining (CM) and the PAM were compared. The energy efficiency was analyzed by specific cutting energy. The cutting force and surface roughness of PAM decreased by 60.2% and 70.5%, respectively, in optimal PAM machining conditions.