Migration and invasion of oral squamous carcinoma cells is promoted by WNT5A, a regulator of cancer progression

Non-coding RNAs in oral cancer: Emerging biomarkers and therapeutic frontier

Around the world, oral cancer (OC) is a major public health problem, resulting in a significant number of deaths each year. Early detection and treatment are crucial for improving patient outcomes. Recent progress in DNA sequencing and transcriptome profiling has revealed extensive non-coding RNAs (ncRNAs) transcription, underscoring their regulatory importance. NcRNAs influence genomic transcription and translation and molecular signaling pathways, making them valuable for various clinical applications. Combining spatial transcriptomics (ST) and spatial metabolomics (SM) with single-cell RNA sequencing provides deeper insights into tumor microenvironments, enhancing diagnostic and therapeutic precision for OC. Additionally, the exploration of salivary biomarkers offers a non-invasive diagnostic avenue. This article explores the potential of ncRNAs as diagnostic and therapeutic tools for OC.

WNT7B promotes cancer progression via WNT/β-catenin signaling pathway and predicts a poor prognosis in oral squamous cell carcinoma

BACKGROUND

WNT7B is a glycoprotein that plays a crucial role in tumorigenesis. This study aimed to investigate the role of WNT7B in oral squamous cell carcinoma (OSCC).

METHODS

Bioinformatic databases, immunohistochemistry, a real-time polymerase chain reaction, western blot, and enzyme-linked immunosorbent assay were used to detect WNT7B expression in OSCC. The clinical and prognostic importance of WNT7B expression was evaluated. WNT7B expression was examined in oral leukoplakia and carcinoma induced by 4-nitroquinoline 1-oxide in mice. Loss- and gain-of-function analyses were performed to elucidate the role of WNT7B in OSCC cells. Subcutaneous tumor model was established to observe the effects of WNT7B on tumor growth. Co-Immunoprecipitation was used to explore the Frizzled receptors that WNT7B may bind to.

RESULTS

WNT7B upregulated in OSCC and associated with lymph node metastasis, perineural invasion, and an unfavorable prognosis in patients with OSCC. A gradual increased in WNT7B expression during the malignant progression of OSCC. WNT7B promoted cell proliferation, migration, invasion, while silencing WNT7B abolished these effects. Knocking down the expression of WNT7B inhibits tumor growth in vivo. WNT7B functions by binding to the Frizzled 7 receptor and facilitates the nuclear translocation of β-catenin.

CONCLUSIONS

WNT7B contributes to the progression of OSCC by modulating the WNT/β-catenin signaling pathway. These findings highlight the potential of WNT7B as a novel prognostic biomarker and promising therapeutic target for OSCC.

High expression of ACTL6A leads to poor prognosis of oral squamous cell carcinoma patients through promoting malignant progression

OBJECTIVE

The aim was to research ACTL6A's role in oral squamous cell carcinoma (OSCC).

METHODS

OSCC and normal samples were obtained from patients and public databases. GSEA was performed. CIBERSORT was utilized to analyze immune landscape. Kaplan-Meier survival analysis and multivariate Cox regression analysis were conducted. After knocking down ACTL6A, we performed MTT assay, transwell assays, and flow cytometry to detect the impact of knockdown.

RESULTS

ACTL6A expressed higher in OSCC samples than normal samples. The CNV and mutation rate of TP53 was higher in ACTL6A high-expression group. TFs E2F7 and TP63 and miRNA hsa-mir-381 were significantly related to ACTL6A. ACTL6A could influence immune microenvironment of OSCC. Knockdown of ACTL6A inhibited OSCC cells' proliferation, migration, and invasion. ACTL6A was able to predict OSCC prognosis independently.

CONCLUSION

ACTL6A expressed higher in OSCC than normal samples and it could be used as an independent prognostic marker in OSCC patients.

Aberrant Upregulation of RUNX3 Activates Developmental Genes to Drive Metastasis in Gastric Cancer

Gastric cancer metastasis is a major cause of mortality worldwide. Inhibition of RUNX3 in gastric cancer cell lines reduced migration, invasion, and anchorage-independent growth in vitro. Following splenic inoculation, CRISPR-mediated RUNX3-knockout HGC-27 cells show suppression of xenograft growth and liver metastasis. We interrogated the potential of RUNX3 as a metastasis driver in gastric cancer by profiling its target genes. Transcriptomic analysis revealed strong involvement of RUNX3 in the regulation of multiple developmental pathways, consistent with the notion that Runt domain transcription factor (RUNX) family genes are master regulators of development. RUNX3 promoted "cell migration" and "extracellular matrix" programs, which are necessary for metastasis. Of note, we found pro-metastatic genes WNT5A, CD44, and VIM among the top differentially expressed genes in RUNX3 knockout versus control cells. Chromatin immunoprecipitation sequencing and HiChIP analyses revealed that RUNX3 bound to the enhancers and promoters of these genes, suggesting that they are under direct transcriptional control by RUNX3. We show that RUNX3 promoted metastasis in part through its upregulation of WNT5A to promote migration, invasion, and anchorage-independent growth in various malignancies. Our study therefore reveals the RUNX3-WNT5A axis as a key targetable mechanism for gastric cancer metastasis.

SIGNIFICANCE

Subversion of RUNX3 developmental gene targets to metastasis program indicates the oncogenic nature of inappropriate RUNX3 regulation in gastric cancer.

Associations of Wnt5a expression with liver injury in chronic hepatitis B virus infection

BACKGROUND

Aberrant Wnt5a expression contributes to immunity, inflammation and tissue damage. However, it remains unknown whether Wnt5a is associated with liver injury in chronic hepatitis B virus (HBV) infection. We aimed to explore the potential role of Wnt5a expression in liver injury caused by chronic HBV infection.

METHODS

Wnt5a mRNA levels in peripheral blood mononuclear cells (PBMCs) were analyzed in 31 acute-on-chronic hepatitis B liver failure (ACHBLF) patients, 82 chronic hepatitis B (CHB) patients, and 20 healthy controls using quantitative real-time polymerase chain reaction. Intrahepatic Wnt5a protein expression from 32 chronic HBV infection patients and 6 normal controls was evaluated by immunohistochemical staining.

RESULTS

Wnt5a mRNA expression was increased in CHB patients and ACHBLF patients compared to healthy controls and correlated positively with liver injury markers. Additionally, there was a significant correlation between Wnt5a mRNA expression and HBV DNA load in all patients and CHB patients but not in ACHBLF patients. Furthermore, intrahepatic Wnt5a protein expression was elevated in chronic HBV infection patients compared to that in normal controls. Moreover, chronic HBV infection patients with higher hepatic inflammatory grades had increased intrahepatic Wnt5a protein expression compared with lower hepatic inflammatory grades. In addition, the cut-off value of 12.59 for Wnt5a mRNA level was a strong indicator in predicting ACHBLF in CHB patients.

CONCLUSIONS

We found that Wnt5a expression was associated with liver injury in chronic HBV infection patients. Wnt5a might be involved in exacerbation of chronic HBV infection.

Role of Stromal Fibroblast-Induced WNT7A Associated with Cancer Cell Migration Through the AKT/CLDN1 Signaling Axis in Oral Squamous Cell Carcinoma

Wnt signaling plays a crucial role in the progression of various cancers, including oral squamous cell carcinoma (OSCC). However, the tumor microenvironment (TME) regulating Wnt signaling has not yet been fully elucidated. In this study, we investigated whether cancer-associated fibroblasts (CAFs), the primary components of the TME, activate Wnt signaling and promote tumor progression in OSCC. We conducted a Transwell coculture assay using human OSCC cell lines and normal human dermal fibroblasts (NHDFs). NHDFs stimulated WNT7A expression in several OSCC cell lines, especially HO-1-N-1 and HSC-5. An immunohistochemical study using 122 human OSCC samples indicated that high WNT7A expression in tumor cells was significantly associated with invasion depth and poor prognosis. Moreover, WNT7A expression in OSCC cells was positively correlated with α-smooth muscle actin expression in CAFs. WNT7A knockdown in OSCC cells demonstrated that OSCC cells cocultured with NHDFs significantly promoted tumor cell migration and invasion, which was dependent on WNT7A expression in OSCC cells. We also isolated HSC-5 cells from the coculture and conducted microarray analysis to investigate the factors that promote tumor progression induced by WNT7A. Among the various differentially expressed genes, we identified a downregulated gene encoding CLDN1 and confirmed that WNT7A negatively regulated CLDN1 expression in OSCC cells and CLDN1 knockdown in OSCC cells promoted their migration. Phosphokinase array analysis showed that WNT7A activates protein kinase B (AKT) phosphorylation. Activating AKT signaling using the SC79 agonist induced CLDN1 downregulation in OSCC cells. In the coculture assay, the AKT inhibitor MK2206 significantly recovered CLDN1 expression downregulated by WNT7A, resulting in OSCC cell migration suppression. These results suggest that CAFs stimulate OSCC cells to produce WNT7A, following CLDN1 expression downregulation by activating AKT signaling, promoting cancer cell migration. These findings highlight the importance of molecular therapies targeting the TME in OSCC.

Tumorigenic activation around HPV integrated sites in head and neck squamous cell carcinoma

Human papillomavirus (HPV) is causally involved in the development of head and neck squamous cell carcinoma (HNSCC). The integration of HPV drives tumorigenesis through expression of oncogenic viral genes as well as genomic alterations in surrounding regions. To elucidate involvement of epigenetic dysregulation in tumorigenesis, we here performed integrated analyses of the epigenome, transcriptome and interactome using ChIP-seq, RNA-seq and Hi-C and 4C-seq for HPV(+) HNSCCs. We analyzed clinical HNSCC using The Cancer Genome Atlas data and found that genes neighboring HPV integration sites were significantly upregulated and were correlated with oncogenic phenotypes in HPV(+) HNSCCs. While we found four HPV integration sites in HPV(+) HNSCC cell line UPCI-SCC-090 through target enrichment sequencing, 4C-seq revealed 0.5 to 40 Mb of HPV-interacting regions (HPVIRs) where host genomic regions interacted with integrated HPV genomes. While 9% of the HPVIRs were amplified and activated epigenetically forming super-enhancers, the remaining non-amplified regions were found to show a significant increase in H3K27ac levels and an upregulation of genes associated with GO terms, for example, Signaling by WNT and Cell Cycle. Among those genes, ITPR3 was significantly upregulated, involving UPCI-SCC-090-specific super-enhancer formation around the ITPR3 promoter and in the 80-kb-downstream region. The knockdown of ITPR3 by siRNA or CRISPR deletions of the distant enhancer region led to a significant suppression of cell proliferation. The epigenetic activation of HPVIRs was also confirmed in other cell lines, UM-SCC-47 and UM-SCC-104. These data indicate that epigenetic activation in HPVIRs contributes, at least partially, to genesis of HPV(+) HNSCC.

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.

Tumor suppressive functions of WNT5A in rhabdomyosarcoma

Rhabdomyosarcoma (RMS) is a highly aggressive soft tissue malignancy that predominantly affects children. The main subtypes are alveolar RMS (ARMS) and embryonal RMS (ERMS) and the two show an impaired muscle differentiation phenotype. One pathway involved in muscle differentiation is WNT signaling. However, the role of this pathway in RMS is far from clear. Our recent data showed that the canonical WNT/β-Catenin pathway serves a subordinate role in RMS, whereas non-canonical WNT signaling probably is more important for this tumor entity. The present study investigated the role of WNT5A, which is the major ligand of non-canonical WNT signaling, in ERMS and ARMS. Gene expression analysis showed that WNT5A was expressed in human RMS samples and that its expression is more pronounced in ERMS. When stably overexpressed in RMS cell lines, WNT5A decreased proliferation and migration of the cells as demonstrated by BrdU incorporation and Transwell migration or scratch assay, respectively. WNT5A also decreased the self-renewal capacity and the expression of stem cell markers and modulates the levels of muscle differentiation markers as shown by sphere assay and western blot analysis, respectively. Finally, overexpression of WNT5A can destabilize active β-Catenin of RMS cells. A WNT5A knockdown has opposite effects. Together, the results suggest that WNT5A has tumor suppressive functions in RMS, which accompanies downregulation of β-Catenin.

RSPO1-mutated keratinocytes from palmoplantar keratoderma display impaired differentiation, alteration of cell-cell adhesion, EMT-like phenotype and invasiveness properties: implications for squamous cell carcinoma susceptibility in patients with 46XX disorder of sexual development

Background

Secreted R-spondin (RSPO) proteins play a key role in reproductive organ development, epithelial stem cell renewal and cancer induction by reinforcing canonical Wnt signaling. We have previously reported that palmoplantar keratoderma (PPK), predisposition to cutaneous squamous cell carcinoma (SCC) development and sex reversal segregate as autosomal recessive trait in patients carrying RSPO1-mutations.

Although our previous findings suggested that RSPO1 secreted from fibroblasts regulates keratinocyte growth or differentiation, the role of this protein in the epidermis remains largely unexplored. Our study was aimed at expanding the phenotypic, molecular and functional characterization of RSPO1-mutated skin and keratinocytes.

Results

Cultured primary keratinocytes from PPK skin of a RSPO1-mutated XX-sex reversed patient displayed highly impaired differentiation and epithelial-mesenchymal transition (EMT)-like phenotype. Interestingly, RSPO1-mutated PPK skin expressed markers of increased proliferation, dedifferentiation and altered cell–cell adhesion. Furthermore, all these signs were more evident in SCC specimens of the patient. Cultured PPK patient’s keratinocytes exhibited increased expression of cell‒matrix adhesion proteins and extracellular matrix remodeling enzymes. Moreover, they showed invasiveness properties in an organotypic skin model in presence of PPK fibroblasts, which behave like cancer-associated fibroblasts. However, the co-culture with normal fibroblasts or treatment with the recombinant RSPO1 protein did not revert or reduce the EMT-like phenotype and invasion capability of PPK keratinocytes. Notably, RSPO1-mutated PPK fibroblasts induced a hyperproliferative and dedifferentiated phenotype of age-matched normal control plantar keratinocytes. Wnt signaling has a key role in both PPK promotion and SCC development. Accordingly, Wnt mediators were differentially expressed in both PPK keratinocytes and skin specimens of RSPO1-mutated patient compared to control.

Conclusions

Altogether our data indicate that the absence of RSPO1 in patients with 46XX disorder of sexual development affects the skin microenvironment and epidermal integrity, thus contributing to the risk of SCC tumorigenesis in palmoplantar regions exposed to major frictional stresses.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-022-02434-2.

Mucoadhesive film containing α-mangostin shows potential role in oral cancer treatment

Background

Oral cancer is often preceded by a mucosal lesion called an oral potentially malignant disorder (OPMD). Many plant-derived compounds are of value in medicine. The objectives of this study were to develop a soluble mucoadhesive film containing α-mangostin (α-MG), a compound extracted from the peel of mangosteen fruit, and determine its activities against oral cancer cells, against human papillomavirus type 16 (HPV-16) pseudovirus, and its anti-inflammatory properties.

Methods

A soluble mucoadhesive film containing α-MG was prepared. Oral squamous carcinoma cell line (SCC25), murine macrophage cells (RAW264.7), and human gingival fibroblast cell line were cultured. Anticancer activity and viability of SCC25 cells in response to α-MG film solution were determined by MTT assay. HPV-16 pseudovirus was constructed and effects of the film solution on attachment and post-attachment steps of the infection were investigated. Anti-inflammatory activity was assessed by nitric oxide (NO) inhibition. Fibroblast cell migration was determined by in vitro scratch assay.

Results

The soluble α-MG film showed cytotoxic effects on SCC25 cells in concentration > 125 µg/ml with IC₅₀ of 152.5 µg/ml. Antiviral activity against HPV-16 pseudovirus was observed at attachment step, but not at post-attachment step. The film also possessed a strong anti-inflammatory effect and promoted wound healing without cytotoxicity.

Conclusions

Mucoadhesive film containing α-MG has a cytotoxic effect on oral squamous carcinoma cell line and an inhibitory effect on HPV-16 pseudovirus at attachment step. The α-MG film also shows a potent anti-inflammatory activity and enhances wound healing. Thus, the soluble α-MG film may have a potential role in treating oral cancer.

Roles of the Wnt Signaling Pathway in Head and Neck Squamous Cell Carcinoma

Head and neck squamous cell carcinoma (HNSCC) is the most common type of head and neck tumor. It is a high incidence malignant tumor associated with a low survival rate and limited treatment options. Accumulating conclusions indicate that the Wnt signaling pathway plays a vital role in the pathobiological process of HNSCC. The canonical Wnt/β-catenin signaling pathway affects a variety of cellular progression, enabling tumor cells to maintain and further promote the immature stem-like phenotype, proliferate, prolong survival, and gain invasiveness. Genomic studies of head and neck tumors have shown that although β-catenin is not frequently mutated in HNSCC, its activity is not inhibited by mutations in upstream gene encoding β-catenin, NOTCH1, FAT1, and AJUBA. Genetic defects affect the components of the Wnt pathway in oral squamous cell carcinoma (OSCC) and the epigenetic mechanisms that regulate inhibitors of the Wnt pathway. This paper aims to summarize the groundbreaking discoveries and recent advances involving the Wnt signaling pathway and highlight the relevance of this pathway in head and neck squamous cell cancer, which will help provide new insights into improving the treatment of human HNSCC by interfering with the transcriptional signaling of Wnt.

Targeting Oncogenic WNT Signalling with WNT Signalling-Derived Peptides

WNT signalling is known to be a crucial regulator of embryonic development and tissue homeostasis. Aberrant expression of WNT signalling elements or their mutations has been implicated in carcinogenesis and/or the progression of several different cancer types. Investigations of how WNT signalling affects carcinogenesis and cancer progression have revealed that it has essential roles in the regulation of proliferation, apoptosis, and cancer stemness and in angiogenesis and metastasis. Consequently, WNT-targeted therapy has gained much attention and has resulted in the development of several small molecules, the majority of which act as inhibitors of different WNT signalling events. However, although numerous inhibitory WNT signalling drug candidates have been included in clinical trials, no significant breakthroughs have been made. This could possibly be due to problems with inefficient binding to the target, compensatory signalling mechanisms and toxicity towards normal cells. Therapeutic peptides targeting WNT signalling in cancer cells have been developed as an alternative approach, with the hope that they might overcome the limitations reported for small WNT inhibitory molecules. In this chapter, we describe recent developments made in the design and characterization of WNT signalling-derived peptides aiming at their use as alternative cancer therapeutics and/or combined adjuvant therapy to conventional therapies.

Wnt/β-Catenin Signaling in Oral Carcinogenesis

Oral carcinogenesis is a complex and multifactorial process that involves cumulative genetic and molecular alterations, leading to uncontrolled cell proliferation, impaired DNA repair and defective cell death. At the early stages, the onset of potentially malignant lesions in the oral mucosa, or oral dysplasia, is associated with higher rates of malignant progression towards carcinoma in situ and invasive carcinoma. Efforts have been made to get insights about signaling pathways that are deregulated in oral dysplasia, as these could be translated into novel markers and might represent promising therapeutic targets. In this context, recent evidence underscored the relevance of the Wnt/β-catenin signaling pathway in oral dysplasia, as this pathway is progressively "switched on" through the different grades of dysplasia (mild, moderate and severe dysplasia), with the consequent nuclear translocation of β-catenin and expression of target genes associated with the maintenance of representative traits of oral dysplasia, namely cell proliferation and viability. Intriguingly, recent studies provide an unanticipated connection between active β-catenin signaling and deregulated endosome trafficking in oral dysplasia, highlighting the relevance of endocytic components in oral carcinogenesis. This review summarizes evidence about the role of the Wnt/β-catenin signaling pathway and the underlying mechanisms that account for its aberrant activation in oral carcinogenesis.

WNT7A Promotes EGF-Induced Migration of Oral Squamous Cell Carcinoma Cells by Activating β-Catenin/MMP9-Mediated Signaling

Aims and hypothesis

Epidermal growth factor (EGF) has been shown to induce the migration of various cancer cells. However, the underlying signaling mechanisms for EGF-induced migration of oral squamous cell carcinoma (OSCC) remain to be elucidated. WNT7A, a member of the family of 19 Wnt secreted glycoproteins, is commonly associated with tumor development. It is mostly unknown whether and, if so, how EGF modulates WNT7A in OSCC cells. The role of WNT7A in OSCC was thus investigated to explore the underlying signaling mechanisms for EGF-induced migration of OSCC.

Methods

Cell migration was measured by Wound healing assay and Transwell assay. Western blotting was carried out to detect the expression of WNT7A, MMP9, β-catenin, p-AKT, and p-ERK. The cells were transfected with plasmids or siRNA to upregulate or downregulate the expression of WNT7A. The location of β-catenin was displayed by immunofluorescence microscopy. Immunohistochemistry was carried out to confirm the relation between WNT7A expression and OSCC progression.

Results

The present study showed that the levels of WNT7A mRNA and protein were increased by EGF stimulation in OSCC cells. Besides, it was proved that p-AKT, but not p-ERK, mediated the expression of WNT7A protein induced by EGF. Furthermore, the inhibition of AKT activation prevented the EGF-induced increase of WNT7A and matrix metallopeptidase 9 (MMP9) expression and translocation of β-catenin from the cytoplasm to the nucleus. Moreover, histological analysis of OSCC specimens revealed an association between WNT7A expression and poor clinical prognosis of the disease.

Conclusions

The data in this paper indicated that WNT7A could be a potential oncogene in OSCC and identified a novel PI3K/AKT/WNT7A/β-catenin/MMP9 signaling for EGF-induced migration of OSCC cells.

Association of SOX2, OCT4 and WNT5A Expression in Oral Epithelial Dysplasia and Oral Squamous Cell Carcinoma: An Immunohistochemical Study

The cancer stem cells deliver uncontrolled proliferative capacity within the tumor imparting to increasing size while epithelial mesenchymal transition adds to the invasive potential. Studies using specific markers elucidating the role of these phenomena may bring advancement in the targeted therapy of tumor. SOX2 and OCT4 are two among few stem cell markers indicative of proliferative potential and WNT5A is an epithelial mesenchymal transition marker indicative of invasive potential. We aimed to determine the association between expression of SOX2, OCT4 and WNT5A in oral epithelial dysplasia, oral squamous cell carcinoma and normal oral mucosa. 20 cases of oral squamous cell carcinoma, 20 cases of oral epithelial dysplasia (leukoplakia with dysplasia) and 25 normal oral mucosa tissues specimens were immunohistochemically stained to assess SOX2, OCT4 and WNT5A expression. SOX2 expression was higher in oral squamous cell carcinoma than in oral epithelial dysplasia and very low in normal oral mucosa. OCT4 was very low in oral squamous cell carcinoma and oral epithelial dysplasia when compared to SOX2, while negative in normal tissues. Co-expression of SOX2 and OCT4 showed statistically non-significant difference for tumor proliferation. WNT5A expression was found to be increasing from normal oral mucosa to oral epithelial dysplasia and oral squamous cell carcinoma. In conformity with present study, SOX2 itself can act as a potential marker for proliferation in tumor cells while OCT4 has non-significant role in regulation of tumor behavior in oral squamous cell carcinoma as well as in oral epithelial dysplasia. WNT5A can be a putative marker in studying invasive potential of oral squamous cell carcinoma.

Extravillous trophoblast invasion accelerated by WNT3A, 5A, and 10B via CD44

INTRODUCTION

Appropriate extravillous trophoblast (EVT) invasion is essential for successful pregnancy. Previously, we showed that EVTs express CD44, which accelerated EVT invasion. However, its regulation mechanism via CD44 remains unknown. Our hypothesis was that WNT signaling enhanced EVT invasion via CD44. To test this hypothesis, we investigated the effects of WNT ligands on CD44 expression and EVT invasion using EVT cell lines and isolated primary EVTs.

METHODS

We used EVT cell lines (HTR8/SVneo and HChEpC1b) and isolated primary EVTs, extracted from first-trimester trophoblasts. The cells were supplemented with WNT3A, 5A, and 10B. We examined cell invasion and the expressions of CD44 and matrix metalloproteinase (MMP) 9. Next, to clarify the pathway of WNT10B in EVTs, we knock-downed WNT10B using siRNA and activated or inhibited the WNT canonical pathway using an activator (lithium chloride) or inhibitor (FH535, XAV939) with WNT10B addition.

RESULTS

WNT3A, 5A, and 10B accelerated the invasion in the EVT lines and isolated primary EVTs. The expressions of CD44 and MMP9 were also upregulated by WNT ligands. WNT10B knockdown significantly inhibited EVT invasion concomitantly with CD44 expression. The WNT canonical pathway activator upregulated CD44 expression and its inhibitor downregulated it with WNT10B addition.

CONCLUSIONS

The present study is the first to show the possibility that WNT3A, WNT5A, and WNT10B exist upstream of CD44 in EVTs. Among them, WNT10B may be a novel accelerator of EVT invasion. WNT signaling mediated by multiple WNT ligands may contribute to EVT invasion.

Nuclear localization of β-catenin and expression of target genes are associated with increased Wnt secretion in oral dysplasia

OBJECTIVES

To evaluate the localization of β-catenin in oral dysplastic cells, the expression of target genes upregulated in oral dysplasia, and the role of Wnt ligands in these events.

MATERIALS AND METHODS

Subcellular localization of total and non-phosphorylated (transcriptionally active) β-catenin was evaluated by immunofluorescence and biochemical fractionation in dysplastic oral keratinocytes (DOK), non-dysplastic oral keratinocytes (OKF6), oral squamous carcinoma cells (CAL27) and primary oral keratinocytes. Tcf/Lef-dependent transcription was measured by luciferase reporter assays. Expression of target genes, survivin and cyclin D1, was evaluated by RT-qPCR and Western blotting. Wnt secretion was inhibited with the inhibitor of porcupine, C59. Wnt3a and β-catenin were evaluated in biopsies by tissue immunofluorescence.

RESULTS

Immunofluorescence and fractionation experiments showed augmented nuclear β-catenin (total and transcriptionally active) in DOK, when compared with OKF6 and CAL27 cells. Intriguingly, conditioned medium from DOK promoted nuclear accumulation of β-catenin and Tcf/Lef-dependent transcription in OKF6 and primary oral keratinocytes, suggesting the participation of secreted factors. Treatment of DOK with C59 decreased Wnt3a secretion, nuclear β-catenin and the expression of survivin and cyclin D1 at both mRNA and protein levels. Accordingly, DOK secreted higher Wnt3a levels than OKF6, and inhibition of Wnt3a secretion prevented DOK-induced Tcf/Lef-dependent transcription in OKF6. These observations were confirmed in clinical samples, since tissue immunofluorescence analysis showed simultaneous expression of Wnt3a and nuclear β-catenin in oral dysplasia, but not in healthy mucosa biopsies.

CONCLUSION

These data indicate that secretion of Wnt ligands is critical for β-catenin nuclear localization and expression of target genes in oral dysplasia.

Podoplanin emerges as a functionally relevant oral cancer biomarker and therapeutic target

Oral cancer has become one of the most aggressive types of cancer, killing 140,000 people worldwide every year. Current treatments for oral cancer include surgery and radiation therapies. These procedures can be very effective; however, they can also drastically decrease the quality of life for survivors. New chemotherapeutic treatments are needed to more effectively combat oral cancer. The transmembrane receptor podoplanin (PDPN) has emerged as a functionally relevant oral cancer biomarker and chemotherapeutic target. PDPN expression promotes tumor cell migration leading to oral cancer invasion and metastasis. Here, we describe the role of PDPN in oral squamous cell carcinoma progression, and how it may be exploited to prevent and treat oral cancer.

Glycogen synthase kinase-3β mediated regulation of matrix metalloproteinase-9 and its involvement in oral squamous cell carcinoma progression and invasion

PURPOSE

Oral squamous cell carcinoma (OSCC)-related deaths mainly result from invasion of the tumor cells into local cervical lymph nodes. It has been reported that progressive basement membrane loss promotes the metastatic and invasive capacities of OSCCs. Matrix metalloproteinase-9 (MMP-9) is known to play a central role in tumor progression and invasion. However, the role of MMP-9 in OSCC invasion has so far remained paradoxical and little is known about its regulation. Here, we aimed to assess MMP-9 expression regulation and its activation by glycogen synthase kinase-3β during human OSCC progression and invasion.

METHODS

In the present study, 178 human OSCC samples, including 118 fresh samples (18 adjacent normal, 42 noninvasive and 58 invasive tumor samples) and 60 archival human tissue microarray (TMA) tongue cancer samples, were included. mRNA expression, protein expression, MMP-9/-2 activity, protein-protein interaction and Snail, c-Myc, β-catenin and TIMP1 expression were assessed using RT-PCR, immunohistochemistry, Western blotting, co-immunoprecipitation and gelatin zymography analyses, respectively. Wnt5a and LPA mediated MMP-9 regulation was assessed in OCSCC-derived SCC-9 cells exogenously expressing GSK3β (WT) or non phosphoryable GSK3β (S9A).

RESULTS

We observed a progressive up-regulation/activation of MMP-9 at various stages of oral tumor progression/invasion. Positive correlations were observed between MMP-9 and c-Myc expression, MMP-9 and MMP-2 activity, MMP-9 and TIMP1 expression and MMP-9 activity and TIMP1-MMP-9 interaction. In contrast, a negative correlation between phosphorylated β-catenin and MMP-9 expression was observed. Conversely, we found that in oral tongue SCC MMP-9 expression was positively correlated with inactivation of GSK3 signaling. Finally, we found that Wnt5a and LPA mediated increased MMP-9 and decreased GSK3β activities in tongue SCC-derived SCC-9 cells. MMP-9 regulation by GSK3β was confirmed by using phosphoryable/regulatory GSK3β (WT construct) and not by non-phosphoryable GSK3β (S9A construct).

CONCLUSIONS

Collectively, our results show that MMP-9 overexpression and activation are important events occurring during OSCC progression/invasion and that this overexpression/activation is regulated by c-Myc, active MMP-2 and inactive GSK3β mediated pathways.

Frizzled 8 promotes the cell proliferation and metastasis of renal cell carcinoma

Recent reports have shown a rapid rise in the incidence of renal cell carcinoma (RCC), and Wnt (Wingless-related integration site) signaling pathway is important in RCC. Frizzled 8 (FZD8) is a member of Frizzled (FZD) receptor family which could activate canonical or non-canonical Wnt/β-catenin pathways. Nevertheless, the role of FZD8 in RCC is poorly investigated. The immunohistochemical analysis showed high expression of FZD8 in RCC tissues compared with peri-tumor tissues. FZD8 knockdown decreased the ability of proliferation and metastasis of RCC cells. Research revealed that the FZD8 regulated the transcription of Cyclin D1, c-Myc, and could promote the epithelial to mesenchymal transition (EMT) by mediating Vimentin and Snail through the Wnt/β-catenin signaling pathway. In addition, the results of our experiment revealed that FZD8 is involved in the regulation of non-canonical Wnt signaling pathway. These data suggested that the expression of FZD8 may play an important role in the proliferation and metastasis of RCC, and serve as a putative promising drug target for human RCC therapy.

TRAIL, Wnt, Sonic Hedgehog, TGFβ, and miRNA Signalings Are Potential Targets for Oral Cancer Therapy

Clinical studies and cancer cell models emphasize the importance of targeting therapies for oral cancer. The tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is highly expressed in cancer, and is a selective killing ligand for oral cancer. Signaling proteins in the wingless-type mouse mammary tumor virus (MMTV) integration site family (Wnt), Sonic hedgehog (SHH), and transforming growth factor β (TGFβ) pathways may regulate cell proliferation, migration, and apoptosis. Accordingly, the genes encoding these signaling proteins are potential targets for oral cancer therapy. In this review, we focus on recent advances in targeting therapies for oral cancer and discuss the gene targets within TRAIL, Wnt, SHH, and TGFβ signaling for oral cancer therapies. Oncogenic microRNAs (miRNAs) and tumor suppressor miRNAs targeting the genes encoding these signaling proteins are summarized, and the interactions between Wnt, SHH, TGFβ, and miRNAs are interpreted. With suitable combination treatments, synergistic effects are expected to improve targeting therapies for oral cancer.

Higher expression of WNT5A protein in oral squamous cell carcinoma compared with dysplasia and oral mucosa with a normal appearance

WNT5A is a secreted signaling protein that promotes migration and invasion of oral squamous cell carcinoma (OSCC) cells through activation of non‐canonical WNT signaling. Here, we examined expression of WNT5A, β‐catenin, and E‐cadherin by immunohistochemistry in 21 human diagnostic incision biopsies that each had regions of oral mucosa with a normal appearance adjacent to the affected tissue, dysplasia, and OSCC. We also investigated the effect of recombinant WNT5A (rWNT5A) on expression of the cell‐adhesion proteins E‐cadherin and β‐catenin by western blot analysis. No expression of WNT5A protein was present in oral mucosa with a normal appearance or in mild grade dysplasia. However, expression of WNT5A increased along with increasing grade of dysplasia, and the highest expression was detected in OSCCs. Expression of membranous β‐catenin and of E‐cadherin was lower, whereas expression of cytoplasmic β‐catenin was higher, in OSCCs than in non‐cancerous regions. However, there was no correlation between expression of WNT5A and expression of either β‐catenin or E‐cadherin. Furthermore, treatment of OSCC cells with rWNT5A had no effect on the expression of β‐catenin or E‐cadherin. Taken together with previous results, we conclude that WNT5A influences the progression of OSCC without affecting the canonical WNT/β‐catenin pathway and without down‐regulating E‐cadherin. WNT5A may have potential as a biological marker for malignant transformation of dysplasia to OSCC.

Critical roles of Wnt5a-Ror2 signaling in aggressiveness of tongue squamous cell carcinoma and production of matrix metalloproteinase-2 via ΔNp63β-mediated epithelial-mesenchymal transition

OBJECTIVES

We previously showed that ΔNp63β, a splicing variant of ΔNp63, mediated EMT and affected cell motility. DNA microarray was thus performed to elucidate the mechanism that ΔNp63β affects cell motility. As the results, Wnt5a was significantly down-regulated by ΔNp63β overexpression in tongue SCC cell line (SQUU-B) with EMT phenotype.

MATERIALS AND METHODS

Seven OSCC cell lines were used. Expression of ΔNp63, Wnt5a, its receptor Ror2, and matrix metalloproteinases (MMPs) were analyzed by RT-PCR, real-time PCR, and western blotting, and gelatin zymography. Furthermore, we examined the effects of siRNA for Wnt5a or Ror2 and recombinant human Wnt5a (rhWnt5a) on motility of tongue SCC cells. Biopsy specimens from tongue SCC patients were used for immunohistochemical staining of Wnt5a and Ror2.

RESULTS

Wnt5a and Ror2 were expressed only in SQUU-B cells without ΔNp63 expression, and negatively associated with ΔNp63 expression in other cells. ΔNp63β overexpression in SQUU-B cells decreased Wnt5a and Ror2 expression. By Wnt5a or Ror2 knockdown, cell motility was remarkably inhibited, but EMT markers expression was unaffected. MMP-2 expression and the activities inversely correlated with ΔNp63 expression, and were inhibited by Wnt5a or Ror2 knockdown. Cell motility and MMP-2 activities were recovered by adding rhWnt5a in the cells with Wnt5a knockdown, but not in those with Ror2 knockdown. Moreover, immunohistochemical analyses in tongue SCC specimens found that high expression of Wnt5a or Ror2 was associated with poorer prognosis.

CONCLUSION

Wnt5a-Ror2 signaling enhanced tongue SCC cell aggressiveness and promoted production of MMP-2 following ΔNp63β-mediated EMT.

Optimization, validation, and identification of two reliable antibodies for immunodetection of WNT5A

WNT5A is a secreted, noncanonical WNT signaling protein that has been reported to promote progression of several types of cancer, including oral squamous cell carcinoma. Many WNT5A antibodies are available commercially for immunohistochemistry (IHC) and western blot analysis. Validation of the primary antibodies, however, is often neglected. We characterized antibodies for detecting WNT5A by IHC and western blot analysis. We evaluated one polyclonal and three monoclonal commercially available WNT5A antibodies. After optimization of the IHC assay, all four antibodies showed cytoplasmic WNT5A expression in tissue samples; in contrast, only one antibody detected WNT5A in western blots. A pre-absorption test with recombinant WNT5A showed that AF645 and 3A4 antibodies specifically detected WNT5A in different assays. We suggest that the monoclonal 3A4 antibody is the most appropriate for use with IHC, while the polyclonal AF645 antibody is the best for western blot analysis.

Wnt5a Increases Properties of Lung Cancer Stem Cells and Resistance to Cisplatin through Activation of Wnt5a/PKC Signaling Pathway

The development of chemoresistance to cisplatin regimens causes a poor prognosis in patients with advanced NSCLC. The role of noncanonical Wnt signaling in the regulation of properties of lung cancer stem cells and chemoresistance was interrogated, by accessing capacities of cell proliferation, migration, invasion, and clonogenicity as well as the apoptosis in A549 cell lines and cisplatin-resistant A549 cells treated with Wnt5a conditional medium or protein kinase C (PKC) inhibitor GF109203X. Results showed that the noncanonical Wnt signaling ligand, Wnt5a, could promote the proliferation, migration, invasion, and colony formation in A549 lung adenocarcinoma cells and cisplatin-resistant A549/DDP cells and increase the fraction of ALDH-positive cell in A549/DDP cells. An exposure of cells to Wnt5a led to a significant reduction of A549/DDP cell apoptosis but not A549 cells. An addition of GF109203X could both strikingly increase the baseline apoptosis and resensitize the Wnt5a-inhibited cell apoptosis. Interestingly, an inhibition of Wnt/PKC signaling pathway could reduce properties of lung cancer stem cells, promote cell apoptosis, and resensitize cisplatin-resistant cells to cisplatin via a caspase/AIF-dependent pathway. These data thus suggested that the Wnt5a could promote lung cancer cell mobility and cisplatin-resistance through a Wnt/PKC signaling pathway and a blockage of this signaling may be an alternative therapeutic strategy for NSCLC patients with resistance to chemotherapies.

Reversion-inducing cysteine-rich protein with Kazal motifs and its regulation by glycogen synthase kinase 3 signaling in oral cancer

The reversion-inducing cysteine-rich protein with Kazal motifs (RECK) and glycogen synthase kinase (GSK3) are novel tumor suppressors, and emerging evidence has suggested their active role in oral cancer pathogenesis. In the present study, 112 human samples, including 55 fresh samples of 14 adjacent normal tissues, 25 noninvasive oral tumors, and 18 invasive tumors, were included. The messenger RNA (mRNA) expression, protein expression, and promoter methylation of the RECK gene, as well as the expression of GSK3β, phospho/total β-catenin, and c-myc, were measured by RT-PCR, bisulphate modification-PCR, immunohistochemistry, and Western blot analysis. Additionally, ectopic expression of in/active GSK3β was performed in cell culture experiments. This study provided information on the progressive silencing of RECK gene expression at the protein and mRNA levels paralleled with promoter hypermethylation at various stages of oral tumor invasion. RECK expression and the hypermethylation of the RECK gene promoter were negatively and positively correlated with pS⁹GSK3β/c-myc expression, respectively. Further, a negative trend of RECK protein expression with nuclear β-catenin expression was observed. Induced expression of active GSK3β reversed the RECK silencing in SCC9 cells. Collectively, our results demonstrated that the silencing of the RECK gene, possibly regulated by the GSK3β pathway, is an important event in oral cancer invasion and this pathway could be exploited for therapeutic interventions.

Wnt5a Signaling in Cancer

Wnt5a is involved in activating several non-canonical WNT signaling pathways, through binding to different members of the Frizzled- and Ror-family receptors. Wnt5a signaling is critical for regulating normal developmental processes, including proliferation, differentiation, migration, adhesion and polarity. However, the aberrant activation or inhibition of Wnt5a signaling is emerging as an important event in cancer progression, exerting both oncogenic and tumor suppressive effects. Recent studies show the involvement of Wnt5a in regulating cancer cell invasion, metastasis, metabolism and inflammation. In this article, we review findings regarding the molecular mechanisms and roles of Wnt5a signaling in various cancer types, and highlight Wnt5a in ovarian cancer.

WNT Signaling in Cutaneous Squamous Cell Carcinoma: A Future Treatment Strategy?

The molecular mechanisms underlying cutaneous squamous cell carcinoma are less well established than those for other common skin cancers, but recent evidence has highlighted a potentially critical role for WNT signaling in both the development and progression of cutaneous squamous cell carcinoma. WNT pathways are aberrantly regulated in multiple tumor types (albeit in a context-dependent manner), and this has stimulated the development of WNT inhibitory compounds for cancer treatment. In this review, we examine existing evidence for a role of WNT signaling in cutaneous squamous cell carcinoma and discuss if WNT inhibition represents a realistic therapeutic strategy for the future.