SC66 inhibits the proliferation and induces apoptosis of human bladder cancer cells by targeting the AKT/β-catenin pathway

Bladder cancer (BC) is a major disease of the genitourinary tract, and chemotherapy is one of the main treatments commonly used at present. SC66 is a new type of allosteric AKT inhibitor that is reported to play an effective inhibitory role in the progression of many other types of tumours, but there is no reported research on its role in BC. In this study, we found that SC66 significantly inhibited the proliferation and EMT-mediated migration and invasion of T24 and 5637 cells. In addition, experiments confirmed that SC66 achieved its antitumour effect by inducing cell apoptosis and affecting the cell cycle. Luciferase assays confirmed that SC66 exerted an antitumour effect through the AKT/β-catenin signalling pathway, and this inhibitory effect was reversed after the addition of the β-catenin signalling pathway activator, CHIR-99021. In addition, animal studies have shown that, compared with the control group, the experimental group with SC66 intraperitoneal injection showed significantly reduced the tumour weight and volume in nude mice with T24 tumours and that SC66 combined with cisplatin achieved better inhibition on tumours. Western blot analysis and immunohistochemistry staining confirmed that SC66 inhibited the EMT process in vivo and induced apoptosis through the AKT/β-catenin signalling pathway. In conclusion, our study demonstrated that SC66 exerts a significant antitumour effect through the AKT/β-catenin signalling pathway, thereby providing a new potential treatment for BC.     

miR-218 promoted the apoptosis of human ovarian carcinoma cells via suppression of the WNT/β-catenin signaling pathway

MicroRNA-218 (miR-218) is a short, noncoding RNA, with multiple biological functions. In this study, we aimed to investigate the potential effects of miR-218 on the apoptosis of human ovarian carcinoma cells and the underlying mechanisms by which miR-218 exerted its actions. After over-expressing miR-218 in human ovarian carcinoma (OVCAR3) cells, cell viability was determined by MTT method, cell apoptosis was observed by flow cytometry (FCM), mRNA expression of miR-218, Bcl2, Bax was measured by RT-PCR and protein expression levels of Wnt, tankyrase and β-catenin were quantified by Western blots. Over-expression of miR-218 potently suppressed cell viability and promoted the apoptosis of human ovarian carcinoma cells in a time-dependent manner. In addition, the down-regulation of tankyrase expression level was detected in miR-218-over-expressed cells. Following the block of the Wnt/β-catenin signaling pathway using the inhibitor XAV-939, the effects of miR-218 on the proliferation and apoptosis of human ovarian carcinoma cells were significantly suppressed. Augmenting expression of miR-218 and/or miRNA-218 mimicking therapeutics may provide viable avenue for the treatment of ovarian cancer.     

WNT7A regulates tumor growth and progression in ovarian cancer through the WNT/β-catenin pathway

Abnormal activation the WNT/β-catenin signaling pathway has been associated with ovarian carcinomas, but a specific WNT ligand and pertinent downstream mechanisms are not fully understood. In this study, we found abundant WNT7A in the epithelium of serous ovarian carcinomas, but not detected in borderline and benign tumors, normal ovary, or endometrioid carcinomas. To characterize the role of WNT7A in ovarian tumor growth and progression, nude mice were injected either intraperitoneally or subcutaneously with WNT7A knocked down SKOV3.ip1 and overexpressed SKOV3 cells. In the intraperitoneal group, mice receiving SKOV3.ip1 cells with reduced WNT7A expression developed significantly fewer tumor lesions. Gross and histologic examination revealed greatly reduced invasion of WNT7A knockdown cells into intestinal mesentery and serosa compared with the control cells. Tumor growth was regulated by loss or overexpression of WNT7A in mice receiving subcutaneous injection as well. In vitro analysis of cell function revealed that cell proliferation, adhesion, and invasion were regulated by WNT7A. The activity of the T-cell factor/lymphoid enhancer factor (TCF/LEF) reporter was stimulated by overexpression of WNT7A in ovarian cancer cells. Cotransfection with WNT7A and FZD5 receptor further increased activity, and this effect was inhibited by cotransfection with SFRP2 or dominant negative TCF4. Overexpression of WNT7A stimulated matrix metalloproteinase 7 (MMP7) promoter, and mutation of TCF-binding sites in MMP7 promoter confirmed that activation of MMP7 promoter by WNT7A was mediated by β-catenin/TCF signaling. Collectively, these results suggest that reexpression of WNT7A during malignant transformation of ovarian epithelial cells plays a critical role in ovarian cancer progression mediated by WNT/β-catenin signaling pathway.     

Leptin promotes endothelial dysfunction in chronic kidney disease by modulating the MTA1-mediated WNT/β-catenin pathway

Molecular and Cellular Biochemistry - Mutations in the retinal inosine monophosphate dehydrogenase1 (IMPDH1) gene is believed to be one cause of retinitis pigmentosa (RP). The main structural...     

Tension force-induced bone formation in orthodontic tooth movement via modulation of the GSK-3β/β-catenin signaling pathway

Orthodontic force-induced osteogenic differentiation and bone formation at tension sites play a critical role in orthodontic tooth movement. However, the molecular mechanism underlying this phenomenon is poorly understood. In the current study, we investigated the involvement of the GSK-3β/β-catenin signaling pathway, which is critical for bone formation during tooth movement. We established a rat tooth movement model to test the hypothesis that orthodontic force may stimulate bone formation at the tension site of the moved tooth and promote the rate of tooth movement via regulation of the GSK-3β/β-catenin signaling pathway. Our results showed that continued mechanical loading increased the distance between the first and second molar in rats. In addition, the loading force increased bone formation at the tension site, and also increased phospho-Ser9-GSK-3β expression and β-catenin signaling pathway activity. Downregulation of GSK-3β activity further increased bone parameters, including bone mineral density, bone volume to tissue volume and trabecular thickness, as well as ALP- and osterix-positive cells at tension sites during tooth movement. However, ICG-001, the β-catenin selective inhibitor, reversed the positive effects of GSK-3β inhibition. In addition, pharmaceutical inhibition of GSK-3β or local treatment with β-catenin inhibitor did not influence the rate of tooth movement. Based on these results, we concluded that GSK-3β/β-catenin signaling contributes to the bone remodeling induced by orthodontic forces, and can be used as a potential therapeutic target in clinical dentistry.     

Epigenetic disruption of the WNT/ß-catenin signaling pathway in human cancers

Aberrant activation of the WNT/ß-catenin signaling pathway is frequently involved in a broad spectrum of human malignancies. Alternative to genetic deletions and point mutations, epigenetic inactivation of negative WNT regulators, through DNA methylation of promoter CpG islands and/or histone modification, leads to the activation or amplification of aberrant WNT/ß-catenin signaling. In this review, we summarized the contribution of epigenetic dysregulation of WNT/ß-catenin signaling to tumorigenesis and highlighted the importance of epigenetic identification of negative regulators of this pathway as putative tumor suppressors. The reversal of these silenced regulators may be developed as potential cancer therapeutics.     

SETDB1 confers colorectal cancer metastasis by regulation of WNT/β-catenin signaling

BackgroundMetastasis is a critical step in tumor development; however, its specific molecular mechanism is still not fully understood. SETDB1 overexpression is associated with tumor progression and poor prognosis. Here, we explored a novel mechanism by which SETDB1 promotes tumor metastasis in colorectal cancer.MethodsWe conducted database and clinical specimen analysis to determine the expression level of SETDB1 in colorectal cancer, as well as the prognosis of colorectal cancer with overexpressed SETDB1. We used wound healing assays, Transwell assays, and animal studies to study the effect of SETDB1 on colorectal cancer. We performed western blotting, qRT–PCR, immunofluorescence, and co-immunoprecipitation to explore the underlying associations between SETDB1 and β-catenin. We further used wound healing assays, Transwell assays, and animal studies to verify the relationship between SETDB1 and Wnt/β-catenin.ResultsSETDB1 expression was upregulated in colorectal cancer and correlated with poor prognosis. Low expression of SETDB1 decreased invasion and metastasis in colorectal cancer. Low-expression of SETDB1 in colorectal tumor cells decreased β-catenin expression and its nuclear import. We also found that SETDB1 can bind and directly methylate β-catenin, Lastly, we discovered that this metastatic ability could be decreased by activating the Wnt/β-catenin pathway with SETDB1 knock-down.ConclusionSETDB1 is highly expressed in colorectal cancer and plays an important role in the invasion and metastasis through the Wnt/β-catenin pathway. It does so by direct methylation of β-catenin. This novel SETDB1/Wnt/β-catenin pathway provides a new strategy for the treatment of colorectal cancer.     

Regulation of cadherin expression in the chicken neural crest by the Wnt/β-catenin signaling pathway

In neural crest cell development, the expression of the cell adhesion proteins cadherin-7 and cadherin-11 commences after delamination of the neural crest cells from the neuroepithelium. The canonical Wnt signaling pathway is known to drive this delamination step and is a candidate for inducing expression of these cadherins at this time. This project was initiated to investigate the role of canonical Wnt signaling in the expression of cadherin-7 and cadherin-11 by treating neural crest cells with Wnt3a ligand. Expression of cadherin-11 was first confirmed in the neural crest cells for the chicken embryo. The changes in the expression level of cadherin-7 and -11 following the treatment with Wnt3a were studied using real-time RT-PCR and immunostaining. Statistically significant upregulation in the mRNA expression of cadherin-7 and cadherin-11 and in the amount of cadherin-7 and cadherin-11 protein found in cell-cell interfaces between neural crest cells was observed in response to Wnt, demonstrating that cadherin-7 and cadherin-11 expressed by the migrating neural crest cells can be regulated by the canonical Wnt pathway.Key words: neural crest, Wnt, cadherin-7, cadherin-11     

S-Adenosylmethionine-induced adipogenesis is accompanied by suppression of Wnt/β-catenin and Hedgehog signaling pathways

S-Adenosylmethionine (SAM) plays a crucial role as a methyl donor in various biological processes and has been previously shown to be involved in adipogenesis in skeletal muscle. This study was conducted to explore the mechanism of SAM inducing adipogenesis in skeletal muscle. Adipose precursor cells, 3T3-L1, and C2C12 cells, were induced into adipogenic differentiation by addition of SAM in MDI-differentiation media (0.5 mmol/L isobutylmethylxanthine, 1 μm/L dexamethasone, and 10 μg/mL insulin) to explore the role of SAM in promoting adipogenesis. Subsequently, cells were cultured with a medium containing SAM alone at the beginning of differentiation to test the relationship between SAM-induced adipogenesis and Wnt/β-catenin, and Hedgehog signaling pathways that control the cell commitment to adipogenic- or myogenic-differentiation. We found SAM possessed an additive effect with MDI in promoting adipogenesis of 3T3-L1 and C2C12 cells at the beginning of adipogenic differentiation. SAM could also individually induce cell adipogenesis in a dose-dependent manner. Moreover, the expression of Wnt/β-catenin and Hedgehog signals and their targets were suppressed by SAM (P < 0.05). These results demonstrate that SAM, as an increasingly accepted nutritional supplement, can initiate adipogenesis of adipose precursor cells derived from adipose and muscle tissues, a function at least partly correlated with the suppression of Wnt/β-catenin and Hedgehog pathways.     

Early planarian brain regeneration is independent of blastema polarity mediated by the Wnt/β-catenin pathway

Analysis of anteroposterior (AP) axis specification in regenerating planarian flatworms has shown that Wnt/β-catenin signaling is required for posterior specification and that the FGF-like receptor molecule nou-darake (ndk) may be involved in restricting brain regeneration to anterior regions. The relationship between re-establishment of AP identity and correct morphogenesis of the brain is, however, still poorly understood. Here we report the characterization of two axin paralogs in the planarian Schmidtea mediterranea. Although Axins are well known negative regulators of Wnt/β-catenin signaling, no role in AP specification has previously been reported for axin genes in planarians. We show that silencing of Smed-axin genes by RNA interference (RNAi) results in two-tailed planarians, a phenotype previously reported after silencing of Smed-APC-1, another β-catenin inhibitor. More strikingly, we show for the first time that while early brain formation at anterior wounds remains unaffected, subsequent development of the brain is blocked in the two-tailed planarians generated after silencing of Smed-axin genes and Smed-APC-1. These findings suggest that the mechanisms underlying early brain formation can be uncoupled from the specification of AP identity by the Wnt/β-catenin pathway. Finally, the posterior expansion of the brain observed following Smed-ndk RNAi is enhanced by silencing Smed-APC-1, revealing an indirect relationship between the FGFR/Ndk and Wnt/β-catenin signaling systems in establishing the posterior limits of brain differentiation.     

Curcumin suppresses proliferation and invasion in non-small cell lung cancer by modulation of MTA1-mediated Wnt/β-catenin pathway

Curcumin, a naturally occurring phenolic compound, has a diversity of antitumor activities. It has been previously demonstrated that curcumin can inhibit the invasion and metastasis of tumors through activation of the tumor suppressor DnaJ-like heat shock protein 40 (HLJ1). However, the specific roles and mechanisms of curcumin in regulating the malignant behaviors of non-small cell lung cancer (NSCLC) cells still remain unclear. In this study, we found that curcumin could inhibit the proliferation and invasion of NSCLC cells and induce G0/G1 phase arrest. Metastasis-associated protein 1 (MTA1) overexpression has been detected in a wide variety of aggressive tumors and plays an important role on cell invasion and metastasis. Our results showed that curcumin could effectively inhibit the MTA1 expression of NSCLC cells. Further research on the subsequent mechanism showed that curcumin inhibited the proliferation and invasion of NSCLC cells through MTA1-mediated inactivation of Wnt/β-catenin pathway. Wnt/β-catenin signaling was reported to play a critical cooperative role on promoting lung tumorigenesis. Thus, these investigations provided novel insights into the mechanisms of curcumin on inhibition of NSCLC cell growth and invasion and showed potential therapeutic strategies for NSCLC.     

Synergistic effect of indomethacin and NGX6 on proliferation and invasion by human colorectal cancer cells through modulation of the Wnt/β-catenin signaling pathway

This study was designed to investigate whether indomethacin and NGX6 synergistically inhibit the growth and invasiveness of human colon cancer cells (HT-29 and SW620) and to elucidate the molecular mechanism of their action. Cell proliferation was assessed by MTT assay. Cell apoptosis was assessed by acridine orange/ethidium bromide staining (AO–EB) and annexin-V-FITC/PI assay. Invasive behaviors of colorectal cancer cells were examined by cell adhesion, migration, and invasion assays. Gap junctional intercellular communication (GJIC) was assessed by the scrape-loading/dye transfer technique. The subcellular localization and expression of β-catenin protein was examined by immunofluorescence staining and western blot analysis, respectively. Indomethacin and NGX6 had a synergistic effect on inhibiting proliferation and invasiveness of colon cancer HT-29 and SW620 cells, restoring GJIC of HT-29 and SW620, and suppressing translocation of β-catenin from the nucleus and cytoplasm to the plasma membrane. However, they did not have synergistic effects on enhancing apoptosis and suppressing extracellular matrix adhesion of HT-29 and SW620 cells. Indomethacin and NGX6 inhibit the proliferation and invasiveness of HT-29 and SW620 colon cancer cells by attenuating the WNT/ß-catenin signaling pathway.     

Therapeutic potential of targeting the Wnt/β-catenin pathway in the treatment of pancreatic cancer

The Wnt/β-catenin pathway is an important, dysregulated pathway in several tumor types, including pancreatic ductal adenocarcinoma. Although the activation of this pathway is an important component of normal development, its aberrant activation resulting from activating or inactivating mutations in the CTNNB1 gene locus, or in the negative regulators AXIN and APC involving stabilization of β-catenin, and activation of target genes leads to a more aggressive phenotype, suggesting its potential value as a therapeutic target in the treatment of pancreatic ductal adenocarcinoma. A number of small molecule and biologic agents have now been developed for targeting this pathway. This review summarizes the current knowledge about the therapeutic potential of targeting the Wnt pathway with particular emphasis on preclinical/clinical studies in the treatment of pancreatic ductal adenocarcinoma.