Circular RNA hsa_circ_0000277 promotes tumor progression and DDP resistance in esophageal squamous cell carcinoma.

BACKGROUND: Circular RNAs (circRNAs) are well-known regulators of cancer progression and chemoresistance in various types of cancers. This study was performed to investigate the function of hsa_circ_0000277 in esophageal squamous cell carcinoma (ESCC). METHODS: RNA levels were analyzed via the reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Cell Counting Kit-8 (CCK-8) assay was applied to determine cell proliferation and half maximal inhibitory concentration (IC50) of cisplatin (DDP). Colony formation ability was evaluated by colony formation assay. Cell cycle and apoptosis were measured using flow cytometry. RNA immunoprecipitation (RIP), pull-down assay and dual-luciferase reporter assays were performed for target interaction analysis. The protein levels were determined through western blot. Xenograft models were established for researching hsa_circ_0000277 function in vivo. RESULTS: Hsa_circ_0000277 expression was increased in ESCC cells and tissues, and it had important clinical significance. Downregulation of hsa_circ_0000277 repressed ESCC cell proliferation, colony formation, cell cycle, and DDP resistance. Hsa_circ_0000277 acted as a microRNA-873-5p (miR-873-5p) sponge and Sry-related high-mobility group box 4 (SOX4) was validated as a target of miR-873-5p. Moreover, hsa_circ_0000277/miR-873-5p axis and miR-873-5p/SOX4 axis regulated ESCC cell progression and DDP resistance. Hsa_circ_0000277/miR-873-5p axis activated SOX4/Wnt/ß-catenin signaling pathway. Hsa_circ_0000277 facilitated tumorigenesis and DDP resistance by miR-873-5p/SOX4 axis in vivo. CONCLUSION: These findings unraveled that hsa_circ_0000277 promoted ESCC progression and DDP resistance via miR-873-5p/SOX4/Wnt/ß-catenin axis, showing a specific molecular mechanism of carcinogenesis and chemoresistance in ESCC.

Liquidambaric acid inhibits Wnt/ß-catenin signaling and colon cancer via targeting TNF receptor-associated factor 2.

Wnt/ß-catenin signaling is a well-established driver of colon cancer; however, a targeted therapeutic agent has not reached clinics yet. In the present study, we report that the natural compound liquidambaric acid (LDA) inhibits oncogenic Wnt/ß-catenin signaling in vitro and in vivo through its direct target tumor necrosis factor receptor-associated factor 2 (TRAF2). Mechanistically, TRAF2 positively regulates Wnt signaling by interacting with the N-terminal of ß-catenin via its TRAF-C domain; this interaction is disrupted in presence of LDA. Particularly, a TRAF2/ß-catenin/TCF4/TNIK complex is present in colon cancer cells, where TRAF2 is indispensable for the complex formation, and TRAF2/ß-catenin and ß-catenin/TCF4 interactions are disrupted upon LDA treatment. Our findings not only highlight that TRAF2 is an oncogenic regulator of Wnt/ß-catenin signaling and colon cancer but also provide a lead compound targeting TRAF2 for cancer therapy.

The PI3K/AKT pathway promotes fracture healing through its crosstalk with Wnt/ß-catenin.

PI3K/AKT is one of the key pathways that regulate cell behaviors including apoptosis, proliferation, and differentiation. Although previous studies have demonstrated that this pathway is a crucial regulator of osteoblasts, the role of PI3K/AKT in fracture healing remains unclear. It is well known that the Wnt/ß-catenin pathway plays an essential role in bone regeneration. However, whether there exists crosstalk between Wnt/ß-catenin and PI3K/AKT in regulating osteoblasts and bone repair has not been reported. To address these issues, we establish a stabilized fracture model in mice and show that PI3K inhibitor LY294002 substantially inhibits the bone healing process, suggesting that PI3K/AKT promotes fracture repair. More importantly, we report that PI3K/AKT increases phosphorylation of GSK-3ß at Ser9 and phosphorylation of ß-catenin at Ser552 in fracture callus and murine osteoblastic MC3T3-E1 cells, both of which lead to ß-catenin stabilization, nuclear translocation, as well as ß-catenin-mediated TCF-dependent transcription, suggesting that ß-catenin is activated downstream of PI3K/AKT. Furthermore, we show that ICG001, the inhibitor of ß-catenin transcriptional activity, attenuates PI3K/AKT-induced osteoblast proliferation, differentiation, and mineralization, indicating that the PI3K/AKT/ß-catenin axis is functional in regulating osteoblasts. Notably, the PI3K/AKT pathway is also activated by Wnt3a and is involved in Wnt3a-induced osteoblast proliferation and differentiation. Hence, our results reveal the existence of a Wnt/PI3K/AKT/ß-catenin signaling nexus in osteoblasts, highlighting complex crosstalk between PI3K/AKT and Wnt/ß-catenin pathways that are critically implicated in fracture healing.

Differential effects, on oncogenic pathway signalling, by derivatives of the HNF4 α inhibitor BI6015.

BACKGROUND: Gastric cancer (GC) is a highly heterogeneous disease with few "targeted" therapeutic options. Previously, we demonstrated involvement of the transcription factor HNF4α in human GC tumours, and the developmental signal mediator, WNT5A, as a prognostic GC biomarker. One previously developed HNF4α antagonist, BI6015, while not advancing beyond preclinical stages, remains useful for studying GC. METHODS: Here, we characterised the antineoplastic signalling activity of derivatives of BI6015, including transfer of the nitro group from the para position, relative to a methyl group on its benzene ring, to the ortho- and meta positions. We assessed binding efficacy, through surface plasmon resonance and docking studies, while biologic activity was assessed by antimitogenic efficacy against a panel of GC cell lines, and dysregulated transcriptomes, followed by pathway and subpathway analysis. RESULTS: The para derivative of BI6105 was found substantially more growth inhibitory, and effective, in downregulating numerous oncogenic signal pathways, including the embryonic cascade WNT. The ortho and meta derivatives, however, failed to downregulate WNT or other embryonic signalling pathways, unable to suppress GC growth. CONCLUSION: Straightforward strategies, employing bioinformatics analyses, to facilitate the effective design and development of "druggable" transcription factor inhibitors, are useful for targeting specific oncogenic signalling pathways, in GC and other cancers.

A SERM increasing the expression of the osteoblastogenesis and mineralization-related proteins and improving quality of bone tissue in an experimental model of osteoporosis.

Raloxifene is an antiresorptive drug, selective estrogen receptor modulator (SERM) used in the treatment of osteoporosis. Objective To evaluate proteins related to bone repair at the peri-implant bone in a rat model of osteoporosis treated with raloxifene. Material and Methods 72 rats were divided into three groups: SHAM (healthy animals), OVX (ovariectomized animals), and RLX (ovariectomized animals treated with raloxifene). Raloxifene was administered by gavage (1 mg/kg/day). Tibial implantation was performed 30 days after ovariectomy, and animals were euthanized at 14, 42, and 60 days postoperatively. Samples were collected and analyzed by immunohistochemical reactions, molecular analysis, and microtomographic parameters. Results RLX showed intense staining of all investigated proteins at both time points except for RUNX2. These results were similar to SHAM and opposite to OVX, showing mild staining. The PCR gene expression of OC and ALP values for RLX (P<0.05) followed by SHAM and OVX groups. For BSP data, the highest expression was observed in the RLX groups and the lowest expression was observed in the OVX groups (P<0.05). For RUNX2 data, RLX and SHAM groups showed greater values compared to OVX (P<0.05). At 60 days postoperatively, microtomography parameters, related to closed porosity, showed higher values for (Po.N), (Po.V), and (Po) in RLX and SHAM groups, whereas OVX groups showed lower results (P<0.05); (BV) values (P=0.009); regarding total porosity (Po.tot), RLX group had statistically significant lower values than OVX and SHAM groups (P=0.009). Regarding the open porosity (Po.V and Po), the SHAM group presented the highest values, followed by OVX and RLX groups (P<0.05). The Structural Model Index (SMI), RLX group showed a value closer to zero than SHAM group (P<0.05). Conclusions Raloxifene had a positive effect on the expression of osteoblastogenesis/mineralization-related proteins and on micro-CT parameters related to peri-implant bone healing.

Histone deacetylase inhibition-mediated neuronal differentiation via the Wnt signaling pathway in human adipose tissue-derived mesenchymal stem cells.

Histone deacetylase (HDAC) inhibitors, which have an effect on cell homeostasis, cell cycle progression, and terminal differentiation, can act to promote self-renewal and enhance directed differentiation of several lineages of stem cells. However, the roles of HDAC inhibitors on neurogenic differentiation and the mechanisms of Wnt signaling following treatment with HDAC inhibitors remain unclear in stem cells. We hypothesized that HDAC inhibitors regulate downstream Wnt signaling and neurogenic differentiation of mesenchymal stem cells. Following neural induction with supplementary factors, human adipose tissue-derived mesenchymal stem cells (hADSCs) were differentiated into neurogenic cells in vitro. We examined the neurogenic differentiation induced by the HDAC inhibitors, MS-275, sodium butyrate (NaB), trichostatin A (TSA), and valproic acid (VPA), by RT-PCR and western blot analysis. Based on RT-PCR analysis, the expressions of NEUROG2 and NEFL were highly increased following HDAC inhibitor treatment compared with control medium. Most of the neuronal marker genes were expressed when neural-induced hADSCs (NI-hADSCs) were treated with the HDAC inhibitors individually. Interestingly, expression of most of the Wnt-related genes were highly increased following treatment with the HDAC inhibitors, especially with MS-275 treatment. Further, the protein level of Wnt5 was upregulated after neurogenic induction with MS-275 and VPA treatment, based on western blot analysis. Furthermore, we found that c-Jun expression was increased after treatment with the HDAC inhibitors, except with NaB. The protein levels of phosphor-JNK and phosphor-GSK-3ß were upregulated considerably. In conclusion, the HDAC inhibitors could induce neurogenic differentiation of hADSCs by activating canonical Wnt or non-canonical Wnt signaling pathways.

A SERM increasing the expression of the osteoblastogenesis and mineralization-related proteins and improving quality of bone tissue in an experimental model of osteoporosis

Abstract Raloxifene is an antiresorptive drug, selective estrogen receptor modulator (SERM) used in the treatment of osteoporosis. Objective To evaluate proteins related to bone repair at the peri-implant bone in a rat model of osteoporosis treated with raloxifene. Material and Methods 72 rats were divided into three groups: SHAM (healthy animals), OVX (ovariectomized animals), and RLX (ovariectomized animals treated with raloxifene). Raloxifene was administered by gavage (1 mg/kg/day). Tibial implantation was performed 30 days after ovariectomy, and animals were euthanized at 14, 42, and 60 days postoperatively. Samples were collected and analyzed by immunohistochemical reactions, molecular analysis, and microtomographic parameters. Results RLX showed intense staining of all investigated proteins at both time points except for RUNX2. These results were similar to SHAM and opposite to OVX, showing mild staining. The PCR gene expression of OC and ALP values for RLX (P<0.05) followed by SHAM and OVX groups. For BSP data, the highest expression was observed in the RLX groups and the lowest expression was observed in the OVX groups (P<0.05). For RUNX2 data, RLX and SHAM groups showed greater values compared to OVX (P<0.05). At 60 days postoperatively, microtomography parameters, related to closed porosity, showed higher values for (Po.N), (Po.V), and (Po) in RLX and SHAM groups, whereas OVX groups showed lower results (P<0.05); (BV) values (P=0.009); regarding total porosity (Po.tot), RLX group had statistically significant lower values than OVX and SHAM groups (P=0.009). Regarding the open porosity (Po.V and Po), the SHAM group presented the highest values, followed by OVX and RLX groups (P<0.05). The Structural Model Index (SMI), RLX group showed a value closer to zero than SHAM group (P<0.05). Conclusions Raloxifene had a positive effect on the expression of osteoblastogenesis/mineralization-related proteins and on micro-CT parameters related to peri-implant bone healing.

Cinnamaldehyde induces cell apoptosis mediated by a novel circular RNA hsa_circ_0043256 in non-small cell lung cancer.

Cinnamaldehyde (CA), the primary chemical component of the Chinese traditional herb Cinnamomum cassia, is an effective cytotoxic agent against various human cancers. Our previous study indicated that CA could trigger apoptosis in three kinds of non-small cell lung cancer (NSCLC) cells. However, CA mechanism of action in NSCLC has not been unveiled completely. Herein, we showed that a novel circular RNA hsa_circ_0043256 was upregulated in NSCLC cells in response to CA treatment, as detected by microarray and real-time PCR. Hsa_circ_0043256 could inhibit cell proliferation and induce apoptosis, while hsa_circ_0043256 knock-down could promote cell proliferation and restrain apoptosis induced by CA. Bioinformatics analysis predicted that hsa_circ_0043256 could work as a miR-1252 sponge, which could in turn directly target a vital negative regulator of Canonical Wnt signaling, Itchy E3 ubiquitin protein ligase (ITCH), as validated by dual-luciferase assay. Western blot results further confirmed that hsa_circ_0043256 could upregulate ITCH expression, whereas miR-1252 could partially abolish this effect. Interestingly, hsa_circ_0043256 knock-down could weaken Wnt/ß-catenin pathway inhibition induced by CA. Finally, we discovered that CA induced apoptosis and meanwhile upregulated hsa_circ_0043256 expression in vivo. Immunohistochemical analysis revealed that ITCH expression was positively association with hsa_circ_0043256 levels. Above all, we characterized a new mechanism mediated by hsa_circ_0043256/miR-1252/ITCH axis in CA function against NSCLC, providing a novel insight into lung cancer therapy.

Quercetin Remodels the Tumor Microenvironment To Improve the Permeation, Retention, and Antitumor Effects of Nanoparticles.

Our previous work demonstrated that Wnt16 expression in cisplatin-damaged tumor-associated fibroblasts is a key factor contributing to cisplatin resistance in malignancies. Natural antifibrotic compounds with low toxicities are promising candidates to downregulate Wnt16 expression, improving the antitumor effect of cisplatin nanoparticles. Upon screening several natural chemicals, we found that a dietary flavonoid, quercetin, significantly suppresses Wnt16 expression in activated fibroblasts. To facilitate drug delivery, we have prepared a targeted lipid/calcium/phosphate nanoparticle formulation consisting of a prodrug of quercetin, i.e., quercetin phosphate, with a high loading efficiency (26.6% w/w). This quercetin nanoparticle with a particle size of around 35 nm significantly improved the bioavailability and metabolic stability of the parent quercetin. Quercetin phosphate is released from the nanoparticles and converted back to the parent quercetin under physiological conditions. Following systemic administration of quercetin phosphate nanoparticles, a significant downregulation in Wnt16 expression was observed and further yielded a synergistic antitumor effect with cisplatin nanoparticles in a stroma-rich bladder carcinoma model. The α-SMA-positive fibroblast and collagen within the tumor decreased significantly after combination treatment. This suggests that the remodeling of the tumor microenvironment induced by quercetin plays a critical role in promoting the synergy. Indeed, our data further confirmed that quercetin phosphate alone significantly remodeled the tumor microenvironment and increased the penetration of second-wave nanoparticles into the tumor nests. Collectively, quercetin phosphate nanoparticles may be a safe and effective way to improve therapeutic treatment for desmoplastic tumors.

Curcumin reduces lung inflammation via Wnt/ß-catenin signaling in mouse model of asthma.

OBJECTIVES: Asthma is a chronic inflammatory, heterogeneous airway disease affecting millions of people around the world. Curcumin has been found to have anti-inflammatory and antifibrosis effects. Researchers reported that curcumin regulated Wnt/ß-catenin signaling in lots of cells. However, whether curcumin regulates the levels of Wnt/ß-Catenin signaling in lung tissues and DCs (dendritic cells) remains unclear. In this study, we assessed the effects of curcumin on DCs and asthma. METHODS: C57BL/6 mice immunized with OVA (ovalbumin) were challenged thrice with an aerosol of OVA every second day for 8 days. Dexamethasone or curcumin was administered intraperitoneally to OVA-immunized C57BL/6 mice on day 24 once a day for 9 days. Mice were analyzed for effects of curcumin on asthma, inflammatory cell infiltration and cytokine levels in lung tissue. DCs were isolated from mouse bone morrow. The surface markers CD40, CD86 and CD11c of DCs was detected by FACS (fluorescence activated cell sorting) and the function of DCs was detected by mixed lymphocyte reaction. The expression of GSK-3ß and ß-catenin was detected by Western Blot. RESULTS: Results showed that OVA increased the number of inflammatory factors in BALF (bronchoalveolar lavage fluid), elevated lung inflammation scores in mice. Curcumin dose-dependently reversed the alterations induced by OVA in the asthmatic mice. Curcumin activated Wnt/ß-catenin signaling pathway in DCs and asthmatic mouse lungs. CONCLUSIONS: Curcumin could influence the morphology and function of DCs, ease asthma symptom and inflammatory reaction through the activation of Wnt/ß-catenin signaling. These results provide new evidence new evidence for application of curcumin on asthma.

Cassane-type diterpenes from Caesalpinia minax induce apoptosis in pituitary adenoma: structure-activity relationship, ER stress and Wnt/ß-catenin pathways.

Plant-derived natural products have been the highly significant sources of novel antitumor agents. The cassane-type diterpenes of genus Caesalpinia have been reported to bear antiproliferative activities toward different types of cancer cells. In this study, we evaluated the antineoplasmic activities of 16 natural origin cassane-type diterpenes isolated from the CHCl3 extract of the seeds of C. minax in pituitary adenomas cells and identified caesalpin G (CAG) showed the strongest cytotoxicity. Moreover, we further investigated the structure-activity relationship and molecular mechanism of these derivatives systematically. The results confirmed the unsaturated lactone-type ring, hydroxyl at C-7, and alkenyl at C-11 or C-14 functionality as critical for anticancer activity in this family of natural products. In addition, the mechanism experiments also demonstrated unfolded protein response and ER stress and Wnt/ß-catenin pathway were involved in the CAG-induced apoptosis.

Wnt-beta-catenin pathway signals metastasis-associated tumor cell phenotypes in triple negative breast cancers.

Tumor cells acquire metastasis-associated (MA) phenotypes following genetic alterations in them which cause deregulation of different signaling pathways. Earlier, we reported that an upregulation of the Wnt-beta-catenin pathway (WP) is one of the genetic salient features of triple-negative breast cancer (TNBC), and WP signaling is associated with metastasis in TNBC. Using cBioPortal, here we found that collective % of alteration(s) in WP genes, CTNNB1, APC and DVL1 among breast-invasive-carcinomas was 21% as compared to 56% in PAM50 Basal. To understand the functional relevance of WP in the biology of heterogeneous/metastasizing TNBC cells, we undertook this comprehensive study using 15 cell lines in which we examined the role of WP in the context of integrin-dependent MA-phenotypes. Directional movement of tumor cells was observed by confocal immunofluorescence microscopy and quantitative confocal-video-microscopy while matrigel-invasion was studied by MMP7-specific casein-zymography. WntC59, XAV939, sulindac sulfide and beta-catenin siRNA (1) inhibited fibronectin-directed migration, (2) decreased podia-parameters and motility-descriptors, (3) altered filamentous-actin, (4) decreased matrigel-invasion and (5) inhibited cell proliferation as well as 3D clonogenic growth. Sulindac sulfide and beta-catenin siRNA decreased beta-catenin/active-beta-catenin and MMP7. LWnt3ACM-stimulated proliferation, clonogenicity, fibronectin-directed migration and matrigel-invasion were perturbed by WP-modulators, sulindac sulfide and GDC-0941. We studied a direct involvement of WP in metastasis by stimulating brain-metastasis-specific MDA-MB231BR cells to demonstrate that LWnt3ACM-stimulated proliferation, clonogenicity and migration were blocked following sulindac sulfide, GDC-0941 and beta-catenin knockdown. We present the first evidence showing a direct functional relationship between WP activation and integrin-dependent MA-phenotypes. By proving the functional relationship between WP activation and MA-phenotypes, our data mechanistically explains (1) why different components of WP are upregulated in TNBC, (2) how WP activation is associated with metastasis and (3) how integrin-dependent MA-phenotypes can be regulated by mitigating the WP.

Natural compounds with Wnt signal modulating activity.

Covering: up to 2015 The Wnt signalling pathway is essential in many biological processes. The Wnt signal is associated with several diseases, particularly cancer and neurodegenerative diseases. Recently, high-throughput screening systems have been developed to rapidly identify compounds, including natural compounds, that target the Wnt signal. Some studies on natural modulators of the Wnt signal have also suggested their possible target. This review highlights some important natural compounds reported to regulate Wnt activity and describes their possible mechanism of action.

Ginkgo biloba extract promotes osteogenic differentiation of human bone marrow mesenchymal stem cells in a pathway involving Wnt/ß-catenin signaling.

Human bone marrow derived mesenchymal stem cells (BM-MSCs) are a novel cell source used in stem cell therapy to treat bone diseases owing to their high potential to differentiate into osteoblasts. Effective induction of osteogenic differentiation from human BM-MSCs is critical to fulfill their therapeutic potential. In this study, Ginkgo biloba extract (GBE), a traditional herbal medicine, was used to stimulate the proliferation and osteogenic differentiation of human BM-MSCs. The present study revealed that GBE improved the proliferation and osteogenesis of human BM-MSCs in a dose-dependent manner in the range 25-75 mg/l, as indicated by alkaline phosphatase (ALP) activity and calcium content. However, such effect was decreased or inhibited at 100mg/l or higher. The dose-dependent improvement in osteogenesis of human BM-MSCs by GBE was further confirmed by the dose-dependent upregulation of marker genes, osteopontin (OPN) and Collagen I. The increased osteoprotegerin (OPG) expression and minimal expression of receptor activator of nuclear factor-κB ligand (RANKL) suggested that GBE also inhibited osteoclastogenesis of human BM-MSCs. Further mechanistic study demonstrated that the transcriptional levels of bone morphogenetic protein 4 (BMP4) and runt-related transcription factor 2 (RUNX2) in the BMP signaling, ß-catenin and Cyclin D1 in the Wnt/ß-catenin signaling, increased significantly during GBE-promoted osteogenesis. Meanwhile, loss-of-function assay with the signaling inhibitor(s) confirmed that the BMP and Wnt/ß-catenin signaling pathways were indispensable during the GBE-promoted osteogenesis, suggesting that GBE improved osteogenesis via upregulation of the BMP and Wnt/ß-catenin signaling. The present study proposed GBE to be used to upregulate the osteogenic differentiation of human BM-MSCs for new bone formation in BM-MSC-based cell therapy, which could provide an attractive and promising treatment for bone disorders.

The inhibition of Wnt/ß-catenin signaling pathway in human colon cancer cells by sulindac.

The aberrant activation of Wnt/ß-catenin signaling plays important roles in the initial development of colon cancer. Sulindac is a commonly used non-steroidal anti-inflammatory drug. We demonstrated the effects of sulindac on growth inhibition, apoptosis induction, and Wnt/ß-catenin signaling suppression in human colon cancer cells. Sulindac significantly inhibited proliferation of HT-29 colon cancer cells in a dose- and time-dependent manner. Sulindac was found to induce the apoptosis of HT-29 cells and inhibit the Wnt/ß-catenin pathway. The inhibition was further confirmed by the decreased protein levels of ß-catenin. The results indicate that sulindac may play a beneficial role in the comprehensive treatment of colon cancer.

Lipopolysaccharide enhances Wnt5a expression through toll-like receptor 4, myeloid differentiating factor 88, phosphatidylinositol 3-OH kinase/AKT and nuclear factor kappa B pathways in human dental pulp stem cells.

INTRODUCTION: Lipopolysaccharide (LPS) has been implicated in mesenchymal stem cell differentiation processes. Wnt5a, one of the "non-canonical" Wnt family members, is important in signaling stem cell differentiation and in the inflammatory responses of immune cells. Here we studied whether LPS can regulate the expression of Wnt5a in human dental pulp stem cells (hDPSCs) and investigated the intracellular signaling pathways activated by LPS. METHODS: Wnt5a mRNA and protein expression changes in hDPSCs were investigated by real-time polymerase chain reaction analysis and enzyme-linked immunosorbent assay. In addition, real-time polymerase chain reaction, enzyme-linked immunosorbent assay, and luciferase activity assays were used to determine whether toll-like receptor 4 (TLR4), myeloid differentiating factor 88 (MyD88), nuclear factor kappa B (NF-kB), or the phosphatidylinositol 3-OH kinase (PI3K)/AKT pathways are involved in LPS-induced Wnt5a expression. The activation of PI3K and AKT in hDPSCs was measured by Western blot analysis. RESULTS: Wnt5a mRNA and protein expression was rapidly increased in response to LPS in a time- and dose-dependent manner. LPS-induced Wnt5a expression was effectively attenuated by administration of a TLR4 neutralizing antibody, MyD88 inhibitory peptide, PI3-kinase inhibitors (LY294002 and wortmannin), an AKT inhibitor, or NF-κB inhibitor (pyrrolidine dithiocarbamate), IκBa phosphorylation inhibitor (Bay 117082), or IκB protease inhibitor (L-1-tosylamido-2-phenylethyl chloromethyl ketone). Treatment of hDPSCs with LPS activated PI3-kinase (p85) and AKT signaling in a time-dependent manner. Moreover, LPS-mediated increases in κB-luciferase activity were diminished by the overexpression of dominant negative mutants of TLR4, MyD88, p85, AKT, and IκBa. CONCLUSIONS: These results demonstrated that LPS-induced Wnt5a expression was mediated through the TLR4/MyD88/PI3-kinase/AKT pathway, which then initiated NF-κB activation in hDPSCs.

Wnt signaling and hepatocarcinogenesis: molecular targets for the development of innovative anticancer drugs.

Hepatocellular carcinoma (HCC) is one of the most common causes of cancer death worldwide. HCC can be cured by radical therapies if early diagnosis is done while the tumor has remained of small size. Unfortunately, diagnosis is commonly late when the tumor has grown and spread. Thus, palliative approaches are usually applied such as transarterial intrahepatic chemoembolization and sorafenib, an anti-angiogenic agent and MAP kinase inhibitor. This latter is the only targeted therapy that has shown significant, although moderate, efficiency in some individuals with advanced HCC. This highlights the need to develop other targeted therapies, and to this goal, to identify more and more pathways as potential targets. The Wnt pathway is a key component of a physiological process involved in embryonic development and tissue homeostasis. Activation of this pathway occurs when a Wnt ligand binds to a Frizzled (FZD) receptor at the cell membrane. Two different Wnt signaling cascades have been identified, called non-canonical and canonical pathways, the latter involving the ß-catenin protein. Deregulation of the Wnt pathway is an early event in hepatocarcinogenesis and has been associated with an aggressive HCC phenotype, since it is implicated both in cell survival, proliferation, migration and invasion. Thus, component proteins identified in this pathway are potential candidates of pharmacological intervention. This review focuses on the characteristics and functions of the molecular targets of the Wnt signaling cascade and how they may be manipulated to achieve anti-tumor effects.

Direct targeting of ß-catenin: Inhibition of protein-protein interactions for the inactivation of Wnt signaling.

The activation of developmental signaling pathways such as Notch, Hedgehog and Wnt has implications in the onset and progression of numerous types of cancer. Consequently, targeting of such pathways is considered an attractive therapeutic approach. Inhibition of the Wnt signaling cascade proves to be complicated, in part, due to the lack of druggable pathway components. The central hub in Wnt signaling is the protein ß-catenin, which is involved in numerous protein-protein interactions. In general, the inhibition of protein-protein interactions is challenging in particular with binding interfaces lacking pronounced hydrophobic pockets. Herein, we give an overview of ß-catenin-protein interactions, and we review active agents that were reported to inhibit canonical Wnt signaling via direct targeting of ß-catenin.

Isoflavones as a smart curer for non-alcoholic fatty liver disease and pathological adiposity via ChREBP and Wnt signaling.

OBJECTIVE: Non-alcoholic fatty liver disease (NAFLD) and pathological adiposity has emerged as an important modern disease. Along with this, the requirement for alternative and natural medicine for preventing NAFLD and adiposity has been increasing rapidly and considerably. In this report, we will review the biological effect and mechanisms of soy isoflavones on NAFLD and pathologic adiposity mainly through the novel pathways, de novo lipogenic carbohydrate responsive element binding protein (ChREBP) and anti-adipogenic Wnt signaling. METHODS: This paper reviews in vitro and in vivo isoflavone studies published in 2002 to 2011 in North America and East Asia. RESULTS: Collectively, the data support a beneficial relation of isoflavones and NAFLD and/or adiposity. Isoflavones suppress ChREBP signaling via protein kinase A (PKA) and/or 5'-AMP activated protein kinase (AMPK)-dependent phosphorylation, which prevents ChREBP from binding to the promoter regions of lipogenic enzyme. Furthermore, isoflavones directly stimulate Wnt signaling via estrogen receptors-dependent pathway, which inactivates glycogen synthase kinase-3 beta (GSK-3ß), transactivate T-cell factor/lymphoid-enhancer factor (TCF/LEF), the effector of Wnt signaling, degrade adipogenic peroxisome proliferator-activated receptor γ (PPARγ), augment p300/CBP, the transcriptional co-activators of TCF/LEF. CONCLUSIONS: Natural compound isoflavones may be useful alternative medicines in preventing NAFLD and pathological adiposity and this action may be partially associated with ChREBP and Wnt signaling.

Reactive oxygen species mediate arsenic induced cell transformation and tumorigenesis through Wnt/ß-catenin pathway in human colorectal adenocarcinoma DLD1 cells.

Long term exposure to arsenic can increase incidence of human cancers, such as skin, lung, and colon rectum. The mechanism of arsenic induced carcinogenesis is still unclear. It is generally believed that reactive oxygen species (ROS) may play an important role in this process. In the present study, we investigate the possible linkage between ROS, ß-catenin and arsenic induced transformation and tumorigenesis in human colorectal adenocarcinoma cell line, DLD1 cells. Our results show that arsenic was able to activate p47(phox) and p67(phox), two key proteins for activation of NADPH oxidase. Arsenic was also able to generate ROS in DLD1 cells. Arsenic increased ß-catenin expression level and its promoter activity. ROS played a major role in arsenic-induced ß-catenin activation. Treatment of DLD1 cells by arsenic enhanced both transformation and tumorigenesis of these cells. The tumor volumes of arsenic treated group were much larger than those without arsenic treatment. Addition of either superoxide dismutase (SOD) or catalase reduced arsenic induced cell transformation and tumor formation. The results indicate that ROS are involved in arsenic induced cell transformation and tumor formation possible through Wnt/ß-catenin pathway in human colorectal adenocarcinoma cell line DLD1 cells.