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Once urinary bladder cancer (UBC) develops into muscle-invasive bladder cancer, its mortality rate increases dramatically. However, the molecular mechanisms of UBC invasion and metastasis remain largely unknown. Herein, using 5637 UBC cells, we generated two sublines with low (5637 NMI) and high (5637 HMI) invasive capabilities. Mass spectrum analyses revealed that the Wnt family protein Wnt7a is more highly expressed in 5637 HMI cells than in 5637 NMI cells. We also found that increased Wnt7a expression is associated with UBC metastasis and predicted worse clinical outcome in UBC patients. Wnt7a depletion in 5637 HMI and T24 cells reduced UBC cell invasion and decreased levels of active β-catenin and its downstream target genes involved in the epithelial-to-mesenchymal transition (EMT) and extracellular matrix (ECM) degradation. Consistently, treating 5637 NMI and J82 cells with recombinant Wnt7a induced cell invasion, EMT, and expression of ECM degradation–associated genes. Moreover, TOP/FOPflash luciferase assays indicated that Wnt7a activated canonical β-catenin signaling in UBC cells, and increased Wnt7a expression was associated with nuclear β-catenin in UBC samples. Wnt7a ablation suppressed matrix metalloproteinase 10 (MMP10) expression, and Wnt7a overexpression increased MMP10 promoter activity through two TCF/LEF promoter sites, confirming that Wnt7a-mediated MMP10 activation is mediated by the canonical Wnt/β-catenin pathway. Of note, the microRNA miR-370-3p directly repressed Wnt7a expression and thereby suppressed UBC cell invasion, which was partially restored by Wnt7a overexpression. Our results have identified an miR-370-3p/Wnt7a axis that controls UBC invasion through canonical Wnt/β-catenin signaling, which may offer prognostic and therapeutic opportunities.

Nuclear factor (erythroid-derived 2)-like 2 (NRF2) is a master regulator of antioxidant and detoxification activities that can eliminate reactive oxygen species (ROS) produced via irradiation. However, Nrf2 overexpression in liver cancer cells may cause both radioresistance and chemoresistance. Reducing Nrf2 levels can enhance the radiosensitivity of HepG2 cells. Wingless/int-3A (Wnt3A) is a Wnt family protein that mainly activates the canonical Wnt signaling pathway. Recent studies showed that the Axin1-GSK-3β protein complex, a component of the canonical Wnt signaling pathway, can capture Nrf2 and facilitate its ubiquitination and proteasomal degradation in the cytoplasm. This protein complex is degraded upon activation of the Wnt signaling pathway. In the present study, we treated HepG2 cells with the Wnt3A inhibitor LGK-974, an effective and specific PORCN inhibitor that can prevent the formation of a proper folding of the Wnt protein in the endoplasmic reticulum. We found that HepG2 cells became more sensitive to radiation with increasing LGK-974 concentrations. Upon 2 Gy or 4 Gy irradiation, the cells treated with LGK-974 more frequently underwent apoptosis and grew less rapidly. PCR and western blot results showed that inhibiting the secretion of Wnt3A blocked the Wnt signaling pathway and prevented Nrf2 signaling. Notably, the Wnt inhibitor may serve as a radiosensitizing drug.

The objective of this study was to re-evaluate the previously published hematopoietic stem cell (HSC) expansion work using human brain endothelial cells (HUBEC). The expansion effect of contact and non-contact conditions was reported to be equivalent by others. However, we report here different results that the expansion can be achieved only with direct contact. We co-cultured human CD34+ cells with and without HUBEC contact for seven days with cytokines and the readouts were CD34+ / CD38 - phenotype and SCID repopulating cell (SRC) frequency. Also tested was the inhibitory effect of Wnt receptor inhibitor Dkk-1 on HUBEC contact ex vivo expansion; whether an increased expression of Wnt3 occurs on the HUBEC surface; and detection of an increased nuclear localization of beta-catenin in CD34+ / CD38- cells in HUBEC contact culture condition. We conclude that the successful expansion by HUBEC contact culture is a candidate explanation based on the Wnt family protein, possibly Wnt3, expression on HUBEC.

Human WNT3A and WNT14 cDNAs were cloned and characterized. WNT3A and WNT14 encoded WNT family protein of 352 and 365 amino acids, respectively. The 3.0-kb WNT3A mRNA was moderately expressed in placenta, and the 4.4-kb WNT14 mRNA was moderately expressed in skeletal muscle and heart. Although WNT3A mRNA was not detected in 35 human cancer cell lines, WNT14 mRNA was expressed in gastric cancer cell lines TMK1, MKN7, MKN45 and KATO-III. WNT3A and WNT14 genes, clustered in the head to head manner with an interval of about 58.0 kb, were mapped to human chromosome 1q42 region by fluorescence in situ hybridization. WNT3 and WNT15, clustered in human chromosome 17q21 region, are related genes of WNT3A and WNT14, respectively. WNT3A-WNT14 gene cluster and WNT3-WNT15 gene cluster might be generated due to duplication of ancestral gene cluster, just like WNT10A-WNT6 gene cluster and WNT10B-WNT1 gene cluster. Integration sites of mouse mammary tumor virus (MMTV) are located in the mouse chromosomal regions corresponding to these human WNT gene clusters. These results strongly suggest that unidentified nucleotide motif responsible for susceptibility to recombination might exist within the intergenic regions of these WNT gene clusters.

WNTs are a family of secreted-type glycoproteins implicated in embryogenesis and carcinogenesis. We have previously cloned and characterized human WNT2B/WNT13, WNT3, WNT3A, WNT5B, WNT6, WNT7B, WNT8A, WNT8B, WNT10A, WNT10B, WNT11, WNT14, and WNT14B/WNT15. WNT14B gene is clustered with WNT3 gene in human chromosome 17q21, and mRNA expression of WNT14B is significantly up-regulated by retinoic acid during the early phase of neuronal differentiation in human NT2 cells. Here, we identified mouse Wnt14b gene fragments in mouse genome draft sequence AL596108.5 by using bioinformatics, and isolated mouse Wnt14b cDNAs by using cDNA-PCR. Mouse Wnt14b was found to encode a 359-amino-acid WNT family protein with the N-terminal signal peptide, an N-linked glycosylation site, and 24 conserved cysteine residues. Mouse Wnt14b showed 92.5% total-amino-acid identity with human WNT14B, and 64.2% total-amino-acid identity with human WNT14. Mouse Wnt14b gene, consisting of 4 exons, was clustered with mouse Wnt3 gene in mouse chromosome 11. Mouse Wnt14b mRNA was relatively highly expressed in 17-day embryo, and also expressed in adult brain, kidney, liver, 7-day embryo, and 11-day embryo. This is the first report on molecular cloning and characterization of mouse Wnt14b.

WNT14B was cloned and characterized in this study. WNT14B encoded 357-amino acid WNT family protein with the signal peptide and an N-linked glycosylation site. WNT14B was most homologous to WNT14 (61.4% total amino acid identity). WNT15 cDNA fragment previously isolated by another group corresponds to a part of ORF of the WNT14B cDNA (codon 216-335). Exon-intron boundaries were conserved between WNT14B and WNT14 genes. WNT14B and WNT3 genes were clustered in the human chromosome 17q21 region in head to head manner. Intergenic region between WNT14B and WNT3 genes was about 33 kb in size. The 6.6-kb WNT14B mRNA was moderately expressed in fetal kidney and adult kidney. Although WNT14B mRNA was not detected in fetal brain and adult brain by northern blot analyses, WNT14B mRNA was detected in brain, especially in occipital lobe, by RNA dot blot analysis. Among 48 human cancer cell lines derived from various tissues, WNT14B was expressed in a teratocarcinoma cell line NT2 with the potential to differentiate into neuronal cells. WNT14B mRNA was significantly up-regulated by all-trans retinoic acid in NT2 cells. These results strongly suggest that WNT14B might be implicated in the early process of neuronal differentiation of NT2 cells induced by retinoic acid.