Wingless ligands and beta-catenin expression in the rat endometrium: The role of Wnt3 and Wnt7a/beta-catenin pathway at the embryo-uterine interface.

Wnt/beta-catenin signaling may play an essential role in endometrial decidualization, placentation, and the establishment of pregnancy. We investigate here the possible roles, immunolocalizations, and synthesis of the Wnt3, Wnt7a, and beta-catenin proteins in the rat endometrium during the estrous cycle and early postimplantation period. Wnt3 and Wnt7a had a similar localization and dynamic expression relative to the endometrial stages. Wnt7a immunostaining was not limited only to the luminal epithelial cells, but also to strong stainings in the stromal and endothelial cells. Wnt3, Wnt7a, and beta-catenin were highly synthesized and colocalized at the trophoblast-decidual interface; and were more obvious in the primary decidual zone, the GTCs, and the ectoplacental cone. Beta-catenin was strongly localized at the borders of the mature decidual cells; however, Wnt3 and Wnt7a immunolocalizations were decreased in those cells. As such, the immunolocalization of Wnt3, Wnt7a, and beta-catenin shifted with decidualization and placentation. The expression level of Wnt3, Wnt7a, and beta-catenin messenger RNAs increased in early pregnancy, and especially between Days 8.5 and 9.5. The dramatic changes in the expression of Wnt3, Wnt7a, and beta-catenin observed during the early days of pregnancy and the estrous cycle may indicate their roles in decidualization, stromal cell proliferation, and trophoblast invasion.

Concurrent Wnt pathway component expression in breast and colorectal cancer.

Wnt signaling pathway regulates important cell functions such as proliferation and migration and is frequently deregulated in colorectal and breast cancer. Thus, it constitutes an attractive therapeutic target with many drugs being investigated in clinical trials. Eighty-two breast and 102 colorectal carcinomas were analyzed for: relative mRNA expression levels of Wnt pathway components namely Wnt3 ligand, Frizzled 7 receptor and LEF1 transcriptional factor, their concurrent expression patterns and their correlation with clinicopathological features. Regarding breast carcinomas, increased relative mRNA expression levels of WNT3 were found in 54 % of cases whereas decreased relative mRNA expression levels were observed in FZD7 and LEF1 in 82 % and 43 % of cases, respectively. Expression levels of WNT3 were significantly correlated with tumour grade (p = 0.021) in breast cancer. As far as colorectal carcinomas are concerned, increased relative mRNA expression levels of WNT3, FZD7 and LEF1 were found in 60 %, 37 % and 48 % of cases respectively. A statistically significant correlation emerged between LEF1expression levels and pT-category (p = 0.027), suggesting a possible association with tumour aggressiveness in colorectal carcinomas. Statistically significant linear correlations were observed between the expression of WNT3/LEF1 (R = 0.233, p = 0.035) and FZD7/LEF1 (R = 0.359, p = 0.001) in breast carcinomas as well as in colorectal carcinomas (R = 0.536, p < 0.01 and R = 0.210, p = 0.034) respectively. Our results demonstrate a possible clinical significance of Wnt pathway gene expression levels in both tumour types. The distinct expression patterns and simultaneous expression of the investigated genes underscore the complexity of this pathway in breast and colorectal carcinogenesis and highlights the necessity of patient selection with regard to the effectiveness of Wnt pathway inhibitors.

Identification of candidate lncRNAs and circRNAs regulating WNT3/ß-catenin signaling in essential hypertension.

Mounting evidence suggests that noncoding RNAs (ncRNAs) contribute to the pathogenesis of cardiovascular diseases. However, their role in essential hypertension (EH) is still unclear. We therefore identified differentially expressed long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs) in EH patients from a high-risk population group and constructed a competing endogenous RNA regulatory network that predicts interactions of potential diagnostic and therapeutic relevance between specific lncRNA/circRNA-microRNA-mRNA triplets. Our analysis identified two lncRNAs, transmembrane protein 183A pseudogene (LOC646616) and leucine aminopeptidase 3 pseudogene 2 (LAP3P2), and two circRNAs, hsa_circ_0039388 and hsa_circ_0038648, that are highly co-expressed with both wingless-type MMTV integration site family member 3 (WNT3) and calcium/calmodulin-dependent protein kinase II inhibitor 2 (CAMK2N2) mRNAs and also share common microRNA binding sites with these two transcripts. We also confirmed that a mutually regulated network composed of LOC646616/microRNA-637/WNT3 controls WNT3 expression and influences viability and invasive properties in human arterial smooth muscle cells in vitro. These findings highlight a novel ncRNA-based regulatory mechanism potentially driving WNT/ß-catenin activation in EH, and suggest that the identified ncRNAs may represent useful biomarkers and therapeutic targets for this condition.

Tanshinone I Enhances Neurogenesis in the Mouse Hippocampal Dentate Gyrus via Increasing Wnt-3, Phosphorylated Glycogen Synthase Kinase-3ß and ß-Catenin Immunoreactivities.

Tanshinone I (TsI), a lipophilic diterpene extracted from Danshan (Radix Salvia miltiorrhizae), exerts neuroprotection in cerebrovascular diseases including transient ischemic attack. In this study, we examined effects of TsI on cell proliferation and neuronal differentiation in the subgranular zone (SGZ) of the mouse dentate gyrus (DG) using Ki-67, BrdU and doublecortin (DCX) immunohistochemistry. Mice were treated with 1 and 2 mg/kg TsI for 28 days. In the 1 mg/kg TsI-treated-group, distribution patterns of BrdU, Ki-67 and DCX positive ((+)) cells in the SGZ were similar to those in the vehicle-treated-group. However, in the 2 mg/kg TsI-treated-group, double labeled BrdU(+)/NeuN(+) cells, which are mature neurons, as well as Ki-67(+), DCX(+) and BrdU(+) cells were significantly increased compared with those in the vehicle-treated-group. On the other hand, immunoreactivities and protein levels of Wnt-3, ß-catenin and serine-9-glycogen synthase kinase-3ß (p-GSK-3ß), which are related with morphogenesis, were significantly increased in the granule cell layer of the DG only in the 2 mg/kg TsI-treated-group. Therefore, these findings indicate that TsI can promote neurogenesis in the mouse DG and that the neurogenesis is related with increases of Wnt-3, p-GSK-3ß and ß-catenin immunoreactivities.

Targeting neurogenesis ameliorates danger assessment in a mouse model of Alzheimer's disease.

Alzheimer's disease (AD) affects 13% of the population over the age of 65. Behavioral and neuropsychiatric symptoms are frequent and affect 80% of patients. Adult hippocampal neurogenesis, which is impaired in AD, is involved in learning and memory. It remains unclear, however, whether increasing adult neurogenesis improves behavioral symptoms in AD. We report that in the 3xTgAD mouse model of AD, chronic Wnt3a overexpression in the ventral hippocampus dentate gyrus (DG) restored adult neurogenesis to physiological levels. The restoration of adult neurogenesis led to full recovery of danger assessment impairment and the effect was blocked by ablation of neurogenesis with X-irradiation. Finally, using a bed nucleus of stria terminalis (BNST) mRNA expression array, we found that the expression of the 5-HT1A receptor in 3xTgAD mice is selectively decreased and normalized by Wnt3a overexpression in the ventral hippocampus DG, and this normalization is neurogenesis dependent. These findings indicate that reestablishing a functional population of hippocampal newborn neurons in adult AD mice rescues behavioral symptoms, suggesting that adult neurogenesis may be a promising therapeutic target for alleviating behavioral deficits in AD patients.

A small molecule screen identifies a novel compound that induces a homeotic transformation in Hydra.

Developmental processes such as morphogenesis, patterning and differentiation are continuously active in the adult Hydra polyp. We carried out a small molecule screen to identify compounds that affect patterning in Hydra. We identified a novel molecule, DAC-2-25, that causes a homeotic transformation of body column into tentacle zone. This transformation occurs in a progressive and polar fashion, beginning at the oral end of the animal. We have identified several strains that respond to DAC-2-25 and one that does not, and we used chimeras from these strains to identify the ectoderm as the target tissue for DAC-2-25. Using transgenic Hydra that express green fluorescent protein under the control of relevant promoters, we examined how DAC-2-25 affects tentacle patterning. Genes whose expression is associated with the tentacle zone are ectopically expressed upon exposure to DAC-2-25, whereas those associated with body column tissue are turned off as the tentacle zone expands. The expression patterns of the organizer-associated gene HyWnt3 and the hypostome-specific gene HyBra2 are unchanged. Structure-activity relationship studies have identified features of DAC-2-25 that are required for activity and potency. This study shows that small molecule screens in Hydra can be used to dissect patterning processes.

Expression of Wnt3 activates Wnt/ß-catenin pathway and promotes EMT-like phenotype in trastuzumab-resistant HER2-overexpressing breast cancer cells.

To understand the mechanisms leading to trastuzumab resistance in HER2-overexpressing breast tumors, we created trastuzumab-insensitive cell lines (SKBR3/100-8 and BT474/100-2). The cell lines maintain HER2 receptor overexpression and show increase in EGF receptor (EGFR). Upon trastuzumab treatment, SKBR3/100-8 and BT474/100-2 cell lines displayed increased growth rate and invasiveness. The trastuzumab resistance in SKBR3/100-8 and BT474/100-2 was accompanied with activation of the Wnt/ß-catenin signaling pathway. Further investigation found that Wnt3 overexpression played a key role toward the development of trastuzumab resistance. The expression of Wnt3 in trastuzumab-resistant cells increased nuclear expression of ß-catenin and transactivated expression of EGFR. The increased Wnt3 in the trastuzumab-resistant cells also promoted a partial EMT-like transition (epithelial-to-mesenchymal transition); increased N-cadherin, Twist, Slug; and decreased E-cadherin. Knockdown of Wnt3 by siRNA restored cytoplasmic expression of ß-catenin and decreased EGFR expression in trastuzumab-resistant cells. Furthermore, the EMT markers were decreased, E-cadherin was increased, and the cell invasiveness was inhibited in response to the Wnt3 downregulation. Conversely, SKBR3 cells which had been stably transfected with full-length Wnt3 exhibited EMT-like transition. The Wnt3 transfectants, SKBR3/Wnt3-7 and SKBR3/Wnt3-9, showed a significant decrease in E-cadherin and increase in N-cadherin, Twist, and Slug. The cells were less sensitive to trastuzumab than parental SKBR3 and vector-transfected cells. In summary, our data suggest that Wnt3 overexpression activates Wnt/ß-catenin signaling pathway that leads to transactivation of EGFR and promotes EMT-like transition. This could be an important mechanism leading to trastuzumab resistance in HER2-overexpressing breast cancer cells.

Amphetamine stimulates Wnt3 increases in rat nucleus accumbens.

Dopaminergic neurotransmission is thought to be involved in reward-related incentive learning and addictive behaviour. Amphetamine will alter glycogen synthase kinase-3ß (GSK-3ß) activity by increasing dopamine transporter efflux rates. We investigated the hypothesis that Wnt signalling will be altered in rat nucleus accumbens within 15 min of injection of amphetamine compared with saline. We isolated RNA from the nucleus accumbens and used reverse transcriptase-PCR to screen for altered Wnt expression. We found that amphetamine had no effect on Wnt5a or Wnt7a expression but increased Wnt3. We then measured protein expression of Wnt3, phosphorylated lipoprotein-related peptide 6, GSK-3ß phosphorylated at serine-9 and tyrosine-216 and total ß-catenin. We found that amphetamine increased Wnt3 protein expression, increased pLRP6 (threonine-1572) levels, increased ß-catenin levels, increased GSK-3ß phosphorylation at serine-9, consistent with inhibition of GSK-3ß activity, and diminished GSK-3ß phosphorylation at tyrosine-216. Our data support the hypothesis that proximate Wnt signalling is rapidly activated by amphetamine in the adult rat nucleus accumbens.

Wnt3 gene expression promotes tumor progression in non-small cell lung cancer.

The Wnt gene family encodes the multi-functional signaling glycoproteins regulating various normal and pathological processes including tumorigenesis. We investigated the clinical significance of the Wnt3 gene expression in relation to its target genes, c-Myc and survivin, in patients with non-small cell lung cancer (NSCLC). One hundred and twenty-eight patients who underwent resection of NSCLC were analyzed. Quantitative reverse transcription polymerase chain reaction (RT-PCR) was performed to evaluate the gene expression of Wnt3, c-Myc, and survivin. Immunohistochemistry was performed to investigate the protein expression of Wnt3, c-Myc, and survivin. The Ki-67 proliferation index and the apoptotic index using the TUNEL method were also evaluated. Twenty-four carcinomas (18.8%) were found to be high-Wnt3 tumors. The high-Wnt3 tumors were significantly more in squamous cell carcinomas than that in adenocarcinomas (P=0.0022). The Wnt3 gene expression was significantly associated with gene expressions of c-Myc (P=0.0103) and survivin (P=0.0009). As a result, the Ki-67 proliferation index was significantly higher in high-Wnt3 tumors than in low-Wnt3 tumors (P=0.0056). The apoptotic index was significantly lower in high-Wnt3 tumors than in low-Wnt3 tumors (P=0.0245). The overall survival rate was significantly lower in patients with high-Wnt3 tumors than in those with low-Wnt3 tumors (P=0.0020). A Cox regression analysis demonstrated that the Wnt3 status was a significant prognostic factor for NSCLC patients (hazard ratio 2.226, P=0.0296). The present study revealed that Wnt3 gene expression was significantly associated with c-Myc and survivin gene expressions, tumor proliferation, and tumor apoptosis. During the progression of NSCLC, Wnt3 overexpression could be associated with the development of more aggressive tumors.

Effect of 5/6 nephrectomized rat serum on epithelial-to-mesenchymal transition in vitro.

OBJECTIVE: To investigate whether the 5/6 nephrectomized (5/6Nx) rats' 12-week serum could lead to tubular epithelial-to-mesenchymal transition (EMT) and its molecular mechanism, so as to probe the potential stimulation from circulation in chronic progressive kidney disease. METHODS: A total of 24 Sprague Dawley (SD) rats were randomly divided into two groups: sham operation group (sham group) and 5/6Nx group. Rats were killed 12 weeks after surgery to obtain 5/6Nx rats' 12-week serum. Then we detected the expression of E-cadherin in renal tubular epithelial cells of the remaining kidney and we investigated whether the 12th week serum of 5/6Nx rats could cause HK-2 (human kidney proximal tubular cell line) cells to transdifferentiate into fibroblasts. RESULTS: Our data confirmed that E-cadherin expression decreased significantly in the remaining kidney at 12 weeks, and the 5/6Nx rats' 12-week serum could suppress E-cadherin protein and mRNA expression (p < 0.05). We also found that the 5/6Nx rats' 12-week serum could upregulate ZEB1, ß-catenin, and wnt3 protein expression (p < 0.05). CONCLUSIONS: Our results demonstrated that the 5/6Nx rats' 12-week serum could suppress the expression of E-cadherin in HK-2 cells. It was partially through modulating the increase of ZEB1. The loss of E-cadherin could lead ß-catenin to localize to the cytoplasm and nucleus, and feed into the Wnt signaling pathway. It means that the pathogenic serum in chronic kidney disease (CKD) plays an important role in the loss of renal function and turns to be a new avenue of research with potential clinical implications.

Focal adhesion kinase protein regulates Wnt3a gene expression to control cell fate specification in the developing neural plate.

Focal adhesion kinase (FAK) is a cytoplasmic tyrosine kinase protein localized to regions called focal adhesions, which are contact points between cells and the extracellular matrix. FAK protein acts as a scaffold to transfer adhesion-dependent and growth factor signals into the cell. Increased FAK expression is linked to aggressive metastatic and invasive tumors. However, little is known about its normal embryonic function. FAK protein knockdown during early Xenopus laevis development anteriorizes the embryo. Morphant embryos express increased levels of anterior neural markers, with reciprocally reduced posterior neural marker expression. Posterior neural plate folding and convergence-extension is also inhibited. This anteriorized phenotype resembles that of embryos knocked down zygotically for canonical Wnt signaling. FAK and Wnt3a genes are both expressed in the neural plate, and Wnt3a expression is FAK dependent. Ectopic Wnt expression rescues this FAK morphant anteriorized phenotype. Wnt3a thus acts downstream of FAK to balance anterior-posterior cell fate specification in the developing neural plate. Wnt3a gene expression is also FAK dependent in human breast cancer cells, suggesting that this FAK-Wnt linkage is highly conserved. This unique observation connects the FAK- and Wnt-signaling pathways, both of which act to promote cancer when aberrantly activated in mammalian cells.