Inactivation of the WNT5A Alternative Promoter B Is Associated with DNA Methylation and Histone Modification in Osteosarcoma Cell Lines U2OS and SaOS-2

Differential expression of WNT5A long and short isoforms in non-muscle-invasive bladder urothelial carcinoma

Wnt ligands belong to a family of secreted glycoproteins in which binding to a range of receptors/co-receptors activates several intracellular pathways. WNT5A, a member of the Wnt family, is classified as a non-canonical Wnt whose activation triggers planar cell polarity (PCP) and Ca+2 downstream pathways. Aberrant expression of WNT5A has been shown to play both protective and harmful roles in an array of conditions, such as inflammatory disease and cancer. In the present study, using histological, immunohistochemical, and molecular methods, we investigated the expression of two isoforms of WNT5A, WNT5A-Short (WNT5A-S) and WNT5A-Long (WNT5A-L) in bladder urothelial carcinoma (UC). Three UC cell lines (RT4, J82, and T24), as well as a normal urothelial cell line, and formalin-fixed, paraffin-embedded (FFPE) transurethral resection (TUR) tissue samples from 17 patients diagnosed with UC were included in the study. WNT5A-L was the predominantly expressed isoform in urothelial cells, although WNT5A-S was also detectable. Further, although no statistically significant difference was found between the percentage of WNT5A-S transcripts in low-grade versus high-grade tumors, we did find a difference between the percentage of WNT5A-S transcripts found in non-invasion versus invasion of the lamina propria, subgroups of non-muscle-invasive tumors. In conclusion, both WNT5A-S and WNT5A-L isoforms are expressed in UC, and the percentage of their expression levels suggests that a higher proportion of WNT5A-S transcription may be associated with lamina propria invasion, a process preceding muscle invasion.

cRel and Wnt5a/Frizzled 5 Receptor-Mediated Inflammatory Regulation Reveal Novel Neuroprotectin D1 Targets for Neuroprotection

Wnt5a triggers inflammatory responses and damage via NFkB/p65 in retinal pigment epithelial (RPE) cells undergoing uncompensated oxidative stress (UOS) and in experimental ischemic stroke. We found that Wnt5a-Clathrin-mediated uptake leads to NFkB/p65 activation and that Wnt5a is secreted in an exosome-independent fashion. We uncovered that docosahexaenoic acid (DHA) and its derivative, Neuroprotectin D1 (NPD1), upregulate c-Rel expression that, as a result, blunts Wnt5a abundance by competing with NFkB/p65 on the Wnt5a promoter A. Wnt5a increases in ischemic stroke penumbra and blood, while DHA reduces Wnt5a abundance with concomitant neuroprotection. Peptide inhibitor of Wnt5a binding, Box5, is also neuroprotective. DHA-decreased Wnt5a expression is concurrent with a drop in NFkB-driven inflammatory cytokine expression, revealing mechanisms after stroke, as in RPE cells exposed to UOS. Limiting the Wnt5a activity via Box5 reduces stroke size, suggesting neuroprotection pertinent to onset and progression of retinal degenerations and stroke consequences. NPD1 disrupts Wnt5a feedback loop at two sites: (1) decreasing FZD5, thus Wnt5a internalization, and (2) by enhancing cREL activity, which competes with p65/NFkB downstream endocytosis. As a result, Wnt5a expression is reduced, and so is its inflammatory signaling in RPE cells and neurons in ischemic stroke.

WNT5A in tumor development and progression: A comprehensive review

The investigation of tumor microenvironment (TME) is essential to better characterize the complex cellular crosstalk and to identify important immunological phenotypes and biomarkers. The niche is a crucial contributor to neoplasm initiation, maintenance and progression. Therefore, a deeper analysis of tumor surroundings could improve cancer diagnosis, prognosis and assertive treatment. Thus, the WNT family exerts a critical action in tumorigenesis of different types of neoplasms due to dysregulations in the TME. WNT5A, an evolutionary WNT member, is involved in several cellular and physiopathological processes, in addition to tissue homeostasis. The WNT5A protein exerts paradoxical effects while acting as both an oncogene or tumor suppressor by regulating several non-canonical signaling pathways, and consequently interfering in cell growth, cytoskeletal remodeling, migration and invasiveness. This review focuses on a thorough characterization of the role of WNT5A in neoplastic transformation and progression, which may help to understand the prognostic potentiality of WNT5A and its features as a therapeutic target in several cancers. Additionally, we herein summarized novel findings on the mechanisms by which WNT5A might favor tumorigenesis or suppression of cancer progression and discussed the recently developed treatment strategies using WNT5A as a protagonist.

The human WNT5A isoforms display similar patterns of expression but distinct and overlapping activities in normal human osteoblasts

WNT5A activates noncanonical Wnt signaling pathways and has critical functions in early development, differentiation, and tissue homeostasis. Two major WNT5A protein isoforms, which in this study we term WNT5A-L(A) and WNT5A-S(B), have been identified that differ by 18 AA at their amino terminus. Functional differences between the isoforms have been indicated in studies utilizing cancer cell lines but the activities of the isoforms in normal cells and during differentiation have not been explored. We examined the WNT5A isoforms in the normal osteoblast cell line hFOB1.19. WNT5A-L(A) and WNT5A-S(B) transcripts increased from Days 3 to 21 of differentiation but WNT5A-S(B) showed a greater fold-change. In undifferentiated cells, there are 2-fold more WNT5A-L(A) than WNT5A-S(B) transcripts. Total intracellular WNT5A protein increased up to 3-fold during differentiation. siRNA knockdown of total WNT5A leads to a decrease in the expression of the differentiation markers, osteocalcin and RUNX2. Conditioned medium containing the isoform proteins [CM-L(A) and CM-S(B)] was used to analyze the effects of the isoforms on β-catenin and noncanonical signaling, proliferation, gene expression, and alkaline phosphatase (ALP) activity. Treatment with both CM-L(A) and CM-S(B) reduced β-catenin signaling. CM-L(A) but not CM-S(B) significantly increased the proliferation of nondifferentiated hFOB1.19 cells. CM-L(A) enhanced osteocalcin transcripts over 2-fold in differentiating cells, whereas CM-S(B) had no effect. Analysis of differentiating cells up to Day 21 revealed no significant effect of treatment with CM-L(A) or CM-S(B) on ALP activity or osteocalcin gene expression. pJNK levels were unaffected in proliferating cells by treatment with neither isoform. pPKC increased slightly in CM-L(A)-treated cells at 15 min but by 2 h pPKC levels were less than the control. CM-S(B) had a more robust effect on pPKC levels that continued up to 2 h. Together these results suggest that the WNT5A isoforms have distinct and overlapping functions in normal osteoblasts.

WNT5B in Physiology and Disease

WNT5B, a member of the WNT family of proteins that is closely related to WNT5A, is required for cell migration, cell proliferation, or cell differentiation in many cell types. WNT5B signals through the non-canonical β-catenin-independent signaling pathway and often functions as an antagonist of canonical WNT signaling. Although WNT5B has a high amino acid identity with WNT5A and is often assumed to have similar activities, WNT5B often exhibits unique expression patterns and functions. Here, we describe the distinct effects and mechanisms of WNT5B on development, bone, adipose tissue, cardiac tissue, the nervous system, the mammary gland, the lung and hematopoietic cells, compared to WNT5A. We also highlight aberrances in non-canonical WNT5B signaling contributing to diseases such as osteoarthritis, osteoporosis, obesity, type 2 diabetes mellitus, neuropathology, and chronic diseases associated with aging, as well as various cancers.

Loss of Endothelium-Derived Wnt5a Is Associated With Reduced Pericyte Recruitment and Small Vessel Loss in Pulmonary Arterial Hypertension

BACKGROUND

Pulmonary arterial hypertension (PAH) is a life-threatening disorder of the pulmonary circulation associated with loss and impaired regeneration of microvessels. Reduced pericyte coverage of pulmonary microvessels is a pathological feature of PAH and is caused partly by the inability of pericytes to respond to signaling cues from neighboring pulmonary microvascular endothelial cells (PMVECs). We have shown that activation of the Wnt/planar cell polarity pathway is required for pericyte recruitment, but whether production and release of specific Wnt ligands by PMVECs are responsible for Wnt/planar cell polarity activation in pericytes is unknown.

METHODS

Isolation of pericytes and PMVECs from healthy donor and PAH lungs was carried out with 3G5 or CD31 antibody-conjugated magnetic beads. Wnt expression profile of PMVECs was documented via quantitative polymerase chain reaction with a Wnt primer library. Exosome purification from PMVEC media was carried out with the ExoTIC device. Hemodynamic profile, right ventricular function, and pulmonary vascular morphometry were obtained in a conditional endothelium-specific Wnt5a knockout ( Wnt5a^ECKO) mouse model under normoxia, chronic hypoxia, and hypoxia recovery.

RESULTS

Quantification of Wnt ligand expression in healthy PMVECs cocultured with pericytes demonstrated a 35-fold increase in Wnt5a, a known Wnt/planar cell polarity ligand. This Wnt5a spike was not seen in PAH PMVECs, which correlated with an inability to recruit pericytes in Matrigel coculture assays. Exosomes purified from media demonstrated an increase in Wnt5a content when healthy PMVECs were cocultured with pericytes, a finding that was not observed in exosomes of PAH PMVECs. Furthermore, the addition of either recombinant Wnt5a or purified healthy PMVEC exosomes increased pericyte recruitment to PAH PMVECs in coculture studies. Although no differences were noted in normoxia and chronic hypoxia, Wnt5a^ECKO mice demonstrated persistent pulmonary hypertension and right ventricular failure 4 weeks after recovery from chronic hypoxia, which correlated with significant reduction, muscularization, and decreased pericyte coverage of microvessels.

CONCLUSIONS

We identify Wnt5a as a key mediator for the establishment of pulmonary endothelium-pericyte interactions, and its loss could contribute to PAH by reducing the viability of newly formed vessels. We speculate that therapies that mimic or restore Wnt5a production could help prevent loss of small vessels in PAH.

Biology and pathogenesis of human osteosarcoma

Osteosarcoma (OS) is a bone tumor of mesenchymal origin, most frequently occurring during the rapid growth phase of long bones, and usually located in the epiphyseal growth plates of the femur or the tibia. Its most common feature is genome disorganization, aneuploidy with chromosomal alterations, deregulation of tumor suppressor genes and of the cell cycle, and an absence of DNA repair. This suggests the involvement of surveillance failures, DNA repair or apoptosis control during osteogenesis, allowing the survival of cells which have undergone alterations during differentiation. Epigenetic events, including DNA methylation, histone modifications, nucleosome remodeling and expression of non-coding RNAs have been identified as possible risk factors for the tumor. It has been reported that p53 target genes or those genes that have their activity modulated by p53, in addition to other tumor suppressor genes, are silenced in OS-derived cell lines by hypermethylation of their promoters. In osteogenesis, osteoblasts are formed from pluripotent mesenchymal cells, with potential for self-renewal, proliferation and differentiation into various cell types. This involves complex signaling pathways and multiple factors. Any disturbance in this process can cause deregulation of the differentiation and proliferation of these cells, leading to the malignant phenotype. Therefore, the origin of OS seems to be multifactorial, involving the deregulation of differentiation of mesenchymal cells and tumor suppressor genes, activation of oncogenes, epigenetic events and the production of cytokines.

PCAF regulates H3 phosphorylation and promotes autophagy in osteosarcoma cells

BACKGROUND

Osteosarcoma is one of malignant cancer. Histone phosphorylation is common in tumors. We explored the effects of p300-CBP-associated factor (PCAF) and phosphorylation of H3S28 in osteosarcoma cancer cell autophagy.

METHODS

Osteosarcoma cancer cell lines were collected and/or transfected with full length PCAF or interference miRNAs to mimic or silence of PCAF expression. Immunoprecipitation assay and GST pull down was used to target targeting PCAF or H3S28ph. H3-/- SNU-C1 cells were transfected with H3WT- or H3S28F-expressing or enhanced green fluorescent protein (EGFP)-tagged LC3 plasmids, in which H3 was tagged with HA. An in vitro kinase activity assay was performed to test whether recombinant full-length PCAF could phosphorylate H3 in the site of S28. The functions on autophagy was detected by number of autophagosomes, number of EGFP-LC3, LC3-II/I, percentage of degradation and expression of autophagy associated gene (ATG).

RESULTS

PCAF positively regulated H3S28ph in osteosarcoma cancer cells; Immunoprecipitation assay and GST pull down demonstrated that PCAF could interact directly with H3 in osteosarcoma cancer cells. In addition, silence of PCAF inhibited the number of autophagosomes, number of EGFP-LC3, LC3-II/I, percentage of degradation and expression of ATG. Moreover, H3S28A (H3S28 mutation) impaired the promoting autophagy effects of PCAF. The PCAF-H3S28ph axis promoted osteosarcoma cancer autophagy viatranscriptional regulation of ATG genes.

CONCLUSION

PCAF regulated H3S28 phosphorylation and their axis promotes autophagy in osteosarcoma cancer cells viatargeting ATG5 and ATG7.

Regulation of DNA methylation levels in the process of oral mucosal regeneration in a rat oral ulcer model

DNA methylation is an important epigenetic mechanism for cellular maintenance. However, the methylation pattern and the key molecule regulated epigenetically in oral mucosal regeneration is unclear. In this study, we generated a rat oral ulcer model and investigated the cell proliferative activities and DNA methylation patterns immunohistochemically. We also performed immunohistochemical analysis of a regulator of epithelial stem/progenitor cell differentiation in the rat model. We demonstrated immunohistochemistry using antibodies for the molecules as follows: Ki-67, a marker of cellular proliferation; 5-methylcytosine (5-mC), a marker of DNA methylation; 5-hydroxymethylcytosine (5-hmC), a marker of DNA demethylation; Dnmt1, a maintenance DNA methyltransferase; Dnmt3a and Dnmt3b, de novo DNA methyltransferases; and Wnt5a, a regulator of stem/progenitor cell differentiation. In this model, re-epithelialization was completed at Day 4 after ulceration. Regenerating mucosal hypertrophy reached a peak at Day 5 and appeared normal at Day 14. Ki-67-positive cells increased at Day 2 and returned to normal at Day 6 after ulceration. The ratio of the expression level of 5-mC to 5-hmC declined at Day 5 and returned to normal at Day 6. The expression level of Dnmt1 had not changed compared to the normal control at every time point. On the other hand, the expression levels of Dnmt3a and Dnmt3b had decreased significantly at Day 5 and returned to normal at Day 6. Moreover, Wnt5a-positive cells increased at Day 5. In conclusion, oral mucosal regeneration was strictly regulated by DNA methylation. Moreover, Wnt5a might play a critical role in oral mucosal regeneration.

c-Jun regulates the promoter of small subunit hemocyanin gene of Litopenaeus vannamei

Hemocyanin (HMC) is a respiratory glycoprotein, which also plays multifunctional non-specific innate immune defense functions in shrimp. However, the transcriptional regulatory mechanisms of the hemocyanin gene expression have not been reported. In the present study, we cloned a 4324 bp fragment of small subunit hemocyanin (HMCs) gene of Litopenaeus vannamei including the 5'-flanking region, from upstream 2475 bp to downstream 1849 bp (exon 1-intron 1-exon 2) by genome walking method. Four deletion constructs were then generated and their promoter activity assessed using the luciferase reporter system. Interestingly, we identified an alternative promoter (+1516/+1849 bp) located in exon 2, which has stronger promoter activity than the full-length or the other constructs. Bioinformatics analyses revealed that the alternative promoter region contains two conserved binding sites of the transcription factor c-Jun. Mutational analysis and electrophoretic mobility shift assay showed that Litopenaeus vannamei c-Jun (Lvc-Jun) binds to the region +1582/+1589 bp and +1831/+1837 bp of the alternative promoter. Furthermore, overexpression of Lvc-Jun significantly increased the alternative promoter activity, while co-transfection with dsRNA-Lvc-Jun significantly reduced the alternative promoter activity of HMCs. Taken together, our present data indicate that the transcription factor Lvc-Jun is essential for the transcriptional regulation of the HMCs gene expression.

ChIP-seq analysis reveals alteration of H3K4 trimethylation occupancy in cancer-related genes by cold atmospheric plasma

Cold atmospheric plasma (CAP) has gained attention for use in cancer treatment owing to its ability to preferentially induce cancer cell death; however, the involved molecular mechanism remains to be elucidated. Herein, an epigenetic effect of CAP on cancer cells was examined by performing a genome-wide ChIP-seq for H3K4me3 in MCF-7 breast cancer cell line. Consequently, 899 genes showed significantly changed methylation level at H3K4 with constructing "Cellular Compromise, DNA Replication, Recombination, Repair, and Cell Cycle" as the top network. Comparisons with expression array data revealed a coincidence between histone modification and gene expression for 18 genes, and the association was confirmed by ChIP-PCR and qRT-PCR for selected genes. The expression of the affected genes, such as HSCB and PRPS1, was recovered when a histone demethylase JARID1A was inhibited. Furthermore, JARID1A was induced by CAP via the reactive oxygen species signaling. The two genes are known as oncogenes and show a higher expression in breast cancer tissue, and this was supported by the decreased colony formation ability of MCF-7 cells when the cells were treated with siRNAs against each gene. Taken together, these data indicate that CAP inhibits cancer cell proliferation by modulating the methylation level of H3K4 corresponding to oncogenes.

The Role of Abnormal Methylation of Wnt5a Gene Promoter Regions in Human Epithelial Ovarian Cancer: A Clinical and Experimental Study

Objective

In the current study, the role of abnormal methylation of Wnt5a gene promoter regions in human epithelial ovarian cancer was investigated.

Methods

Wnt5a expressions were examined by immunohistochemistry in epithelial ovarian tissues (30 normal and 79 human EOC tissues). SKOV3 cells were treated with different concentrations of 5-Aza-CdR (0.5, 5, and 50 μmol/L). The methylation status of the Wnt5a promoter was analyzed using a methylation-specific polymerase chain reaction (MSP), and the expression level of Wnt5a mRNA was detected using quantitative real-time polymerase chain reaction (qRT-PCR). Cell proliferation was measured by MTT assay, and apoptosis was analyzed using flow cytometry.

Results

(1) Compared with normal tissues, Wnt5a expressions were reduced or lost in EOC (P < 0.05). Wnt5a expression had a close relationship with histological grade, FIGO stage, and lymph node metastasis (P = 0.005, P = 0.022, and P = 0.037, resp.). (2) Wnt5a abnormal methylation status existed in ovarian cancer tissues and was higher than that of normal ovarian tissue (P < 0.01). (3) Before treatment with 5-Aza-CdR, the promoter of the Wnt5a gene was methylated in SKOV3 cells; accordingly, Wnt5a mRNA levels were low to absent in SKOV3 cells. (4) Following 5-Aza-CdR treatment, MSP analysis revealed complete demethylation of the Wnt5a promoter in the SKOV3 cell line, particularly at 5 μmol/L 5-Aza-CdR. Wnt5a expression increased in SKOV3 cells following treatment with a demethylating agent (P ≤ 0.001). (5) The growth rate of the cells was inhibited in a dose-dependent manner by treatment with 5-Aza-CdR. (6) The cell apoptosis rate increased gradually after treatment with 0.5, 5, and 50 μmol/L 5-Aza-CdR. The apoptosis rate exists in a dose-dependent relationship with 5-Aza-CdR concentration (F = 779.73, P < 0.01).

Conclusions

Wnt5a gene region promoter aberrant methylation existed in epithelial ovarian cancer, and abnormal methylation of Wnt5a gene promoter regions may be a new target for the treatment of epithelial ovarian cancer.