WNT5A promotes stemness characteristics in nasopharyngeal carcinoma cells leading to metastasis and tumorigenesis

The evolving roles of Wnt signaling in stem cell proliferation and differentiation, the development of human diseases, and therapeutic opportunities

The evolutionarily conserved Wnt signaling pathway plays a central role in development and adult tissue homeostasis across species. Wnt proteins are secreted, lipid-modified signaling molecules that activate the canonical (β-catenin dependent) and non-canonical (β-catenin independent) Wnt signaling pathways. Cellular behaviors such as proliferation, differentiation, maturation, and proper body-axis specification are carried out by the canonical pathway, which is the best characterized of the known Wnt signaling paths. Wnt signaling has emerged as an important factor in stem cell biology and is known to affect the self-renewal of stem cells in various tissues. This includes but is not limited to embryonic, hematopoietic, mesenchymal, gut, neural, and epidermal stem cells. Wnt signaling has also been implicated in tumor cells that exhibit stem cell-like properties. Wnt signaling is crucial for bone formation and presents a potential target for the development of therapeutics for bone disorders. Not surprisingly, aberrant Wnt signaling is also associated with a wide variety of diseases, including cancer. Mutations of Wnt pathway members in cancer can lead to unchecked cell proliferation, epithelial-mesenchymal transition, and metastasis. Altogether, advances in the understanding of dysregulated Wnt signaling in disease have paved the way for the development of novel therapeutics that target components of the Wnt pathway. Beginning with a brief overview of the mechanisms of canonical and non-canonical Wnt, this review aims to summarize the current knowledge of Wnt signaling in stem cells, aberrations to the Wnt pathway associated with diseases, and novel therapeutics targeting the Wnt pathway in preclinical and clinical studies.

WNT Signaling in Stem Cells: A Look into the Non-Canonical Pathway

Tissue homeostasis is crucial for multicellular organisms, wherein the loss of cells is compensated by generating new cells with the capacity for proliferation and differentiation. At the origin of these populations are the stem cells, which have the potential to give rise to cells with both capabilities, and persevere for a long time through the self-renewal and quiescence. Since the discovery of stem cells, an enormous effort has been focused on learning about their functions and the molecular regulation behind them. Wnt signaling is widely recognized as essential for normal and cancer stem cell. Moreover, β-catenin-dependent Wnt pathway, referred to as canonical, has gained attention, while β-catenin-independent Wnt pathways, known as non-canonical, have remained conspicuously less explored. However, recent evidence about non-canonical Wnt pathways in stem cells begins to lay the foundations of a conceivably vast field, and on which we aim to explain this in the present review. In this regard, we addressed the different aspects in which non-canonical Wnt pathways impact the properties of stem cells, both under normal conditions and also under disease, specifically in cancer.

Circular RNA ZNF800 (hsa_circ_0082096) regulates cancer stem cell properties and tumor growth in colorectal cancer

BACKGROUND

Cancer stem cells form a rare cell population in tumors that contributes to metastasis, recurrence and chemoresistance in cancer patients. Circular RNAs (circRNAs) are post-transcriptional regulators of gene expression that sponge targeted microRNA (miRNAs) to affect a multitude of downstream cellular processes. We previously showed in an expression profiling study that circZNF800 (hsa_circ_0082096) was up-regulated in cancer stem cell-enriched spheroids derived from colorectal cancer (CRC) cell lines.

METHODS

Spheroids were generated in suspension spheroidal culture. The ZNF800 mRNA, pluripotency stem cell markers and circZNF800 levels were determined by quantitative RT-PCR. CircZNF800-miRNA interactions were shown in RNA pulldown assays and the miRNA levels determined by stem-loop qRT-PCR. The effects of circZNF800 on cell proliferation were tested by EdU staining followed by flowcytometry. Expression of stem cell markers CD44/CD133, Lgr5 and SOX9 was demonstrated in immunofluorescence microscopy. To manipulate the cellular levels of circZNF800, circZNF800 over-expression was achieved via transfection of in vitro synthesized and circularized circZNF800, and knockdown attained using a CRISPR-Cas13d-circZNF800 vector system. Xenografted nude mice were used to demonstrate effects of circZNF800 over-expression and knockdown on tumor growth in vivo.

RESULTS

CircZNF800 was shown to be over-expressed in late-stage tumor tissues of CRC patients. Data showed that circZNF800 impeded expression of miR-140-3p, miR-382-5p and miR-579-3p while promoted the mRNA levels of ALK/ACVR1C, FZD3 and WNT5A targeted by the miRNAs, as supported by alignments of seed sequences between the circZNF800-miRNA, and miRNA-mRNA paired interactions. Analysis in CRC cells and biopsied tissues showed that circZNF800 positively regulated the expression of intestinal stem cell, pluripotency and cancer stem cell markers, and promoted CRC cell proliferation, spheroid and colony formation in vitro, all of which are cancer stem cell properties. In xenografted mice, circZNF800 over-expression promoted tumor growth, while circZNF800 knockdown via administration of CRISPR Cas13d-circZNF800 viral particles at the CRC tumor sites impeded tumor growth.

CONCLUSIONS

CircZNF800 is an oncogenic factor that regulate cancer stem cell properties to lead colorectal tumorigenesis, and may be used as a predictive marker for tumor progression and the CRISPR Cas13d-circZNF800 knockdown strategy for therapeutic intervention of colorectal cancer.

Cancer stem cells of head and neck squamous cell carcinoma; distance towards clinical application; a systematic review of literature

Head and neck squamous cell carcinoma (HNSCC) is the major pathological type of head and neck cancer (HNC). The disease ranks sixth among the most common malignancies worldwide, with an increasing incidence rate yearly. Despite the development of therapy, the prognosis of HNSCC remains unsatisfactory, which may be attributed to the resistance to traditional radio-chemotherapy, relapse, and metastasis. To improve the diagnosis and treatment, the targeted therapy for HNSCC may be successful as that for some other tumors. Nanocarriers are the most effective system to deliver the anti-cancerous agent at the site of interest using passive or active targeting approaches. The system enhances the drug concentration in HCN target cells, increases retention, and reduces toxicity to normal cells. Among the different techniques in nanotechnology, quantum dots (QDs) possess multiple fluorescent colors emissions under single-source excitation and size-tunable light emission. Dendrimers are the most attractive nanocarriers, which possess the desired properties of drug retention, release, unaffecting by the immune system, blood circulation time enhancing, and cells or organs specific targeting properties. In this review, we have discussed the up-to-date knowledge of the Cancer Stem Cells of Head and Neck Squamous Cell Carcinoma. Although a lot of data is available, still much more efforts remain to be made to improve the treatment of HNSCC.

Peristalsis-Associated Mechanotransduction Drives Malignant Progression of Colorectal Cancer

Introduction

In the colorectal cancer (CRC) tumor microenvironment, cancerous and precancerous cells continuously experience mechanical forces associated with peristalsis. Given that mechanical forces like shear stress and strain can positively impact cancer progression, we explored the hypothesis that peristalsis may also contribute to malignant progression in CRC. We defined malignant progression as enrichment of cancer stem cells and the acquisition of invasive behaviors, both vital to CRC progression.

Methods

We leveraged our peristalsis bioreactor to expose CRC cell lines (HCT116), patient-derived xenograft (PDX1,2) lines, or non-cancerous intestinal cells (HIEC-6) to forces associated with peristalsis in vitro. Cells were maintained in static control conditions or exposed to peristalsis for 24 h prior to assessment of cancer stem cell (CSC) emergence or the acquisition of invasive phenotypes.

Results

Exposure of HCT116 cells to peristalsis significantly increased the emergence of LGR5+ CSCs by 1.8-fold compared to static controls. Peristalsis enriched LGR5 positivity in several CRC cell lines, notably significant in KRAS mutant lines. In contrast, peristalsis failed to increase LGR5+ in non-cancerous intestinal cells, HIEC-6. LGR5+ emergence downstream of peristalsis was dependent on ROCK and Wnt activity, and not YAP1 activation. Additionally, HCT116 cells adopted invasive morphologies when exposed to peristalsis, with increased filopodia density and epithelial to mesenchymal gene expression, in a Wnt dependent manner.

Conclusions

Peristalsis associated forces drive malignant progression of CRC via ROCK, YAP1, and Wnt-related mechanotransduction.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12195-023-00776-w.

Non-canonical Wnt/Ca2+ signaling is essential to promote self-renewal and proliferation in colon cancer stem cells

Introduction

Cancer Stem Cells (CSC) are responsible for maintaining tumor growth, chemoresistance, and metastasis. Therefore, understanding their characteristics is critical to progress in cancer therapy. While the contribution of the canonical Wnt/b-catenin signaling in both normal and CSCs had been well established, the function of non-canonical Wnt signaling cascades in stem cells is unclear. Recently, we reported that Wnt ligands trigger complex signaling in which the canonical and non-canonical responses can be simultaneously activated by one ligand in colon cancer cells, suggesting, therefore, that noncanonical Wnt pathways may also be important in CSCs.

Methods

The present work aimed to know the role of the Wnt/Ca2+ pathway in colon CSCs. We used tumorspheres as a model of CSCs enrichment of CRC cell lines with different Wnt/b-catenin contexts.

Results

Using Wnt3a and Wnt5a as prototype ligands to activate the canonical or the non-canonical pathways, respectively, we found that both Wnt3a and Wnt5a promote sphere-formation capacity and proliferation without stimulating b-catenin-dependent transcription. Upregulation of sphere formation by Wnt5a or Wnt3a requires the downstream activation of Phospholipase C and transcriptional factor NFAT. Moreover, the single specific inhibition of PLC or NFAT, using U73122 and 11R-VIVIT, respectively, leads to impaired sphere formation.

Discussion

Our results indicate that both types of ligands activate the Wnt/Ca2+ signaling axis to induce/maintain the self-renewal efficiency of CSCs, demonstrating to be essential for the functions of CSC in colon cancer.

Transcriptomic profiling revealed FZD10 as a novel biomarker for nasopharyngeal carcinoma recurrence

Background

Nasopharyngeal carcinoma (NPC) is a type of cancers that develops in the nasopharynx, the very upper part of the throat behind the nose. NPC is typically diagnosed in later stages of the disease and has a high rate of recurrence due to the location of the tumor growth site. In this study, we compared the gene expression profiles of NPC tissues from patients with and without recurrence to identify potential molecular biomarkers of NPC recurrence.

Methods

Microarrays were used to analyze the expression of genes in 15 NPC tissues taken at the time of diagnosis and at the site of recurrence following therapeutic treatment. Pathway enrichment analysis was used to examine the biological interactions between the major differentially expressed genes. The target identified was then validated using immunohistochemistry on 86 NPC tissue samples.

Results

Our data showed that the Wnt signaling pathway was enhanced in NPC tissues with recurrence. FZD10, a component of the Wnt signaling pathway, was significantly expressed in NPC tissues, and was significantly associated with NPC recurrence.

Conclusion

Our study provides new insights into the pathogenesis of NPC and identifies FZD10 as a potential molecular biomarker for NPC recurrence. FZD10 may be a promising candidate for NPC recurrence and a potential therapeutic target.

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.

Cancer Stem Cells: From an Insight into the Basics to Recent Advances and Therapeutic Targeting

Cancer is characterized by an abnormal growth of the cells in an uncontrolled manner. These cells have the potential to invade and can eventually turn into malignancy, leading to highly fatal forms of tumor. Small subpopulations of cancer cells that are long-lived with the potential of excessive self-renewal and tumor formation are called cancer stem cells (CSCs) or cancer-initiating cells or tumor stem cells. CSCs can be found in tissues, such as breast, brain, lung, liver, ovary, and testis; however, their origin is still a matter of debate. These cells can differentiate and possess self-renewal capacity maintained by numerous intracellular signal transduction pathways, such as the Wnt/β-catenin signaling, Notch signaling, transforming growth factor-β signaling, and Hedgehog signaling. They can also contribute to numerous malignancies and are an important reason for tumor recurrence and metastasis because they are resistant to the known therapeutic strategies that mainly target the bulk of the tumor cells. This review contains collected and compiled information after analyzing published works of the last three decades. The goal was to gather information of recent breakthroughs related to CSCs, strategies to target CSCs' niche (e.g., nanotechnology with tumor biology), and their signaling pathways for cancer therapy. Moreover, the role of metformin, an antidiabetic drug, acting as a chemotherapeutic agent on CSCs by inhibiting cellular transformation and its selective killing is also addressed.

Wnt5a-mediated autophagy promotes radiation resistance of nasopharyngeal carcinoma

Wnt signaling pathways and autophagy play an essential role in tumor progression. Canonical Wnt signaling pathways in radiation resistance have been studied in the past, but it remains unclear whether the noncanonical Wnt signaling pathways can affect tumor radiation resistance through protective autophagy. Nasopharyngeal carcinoma, a particular subtype of head and neck squamous cell carcinoma, relies on radiation therapy. In this study, we found that radioactive rays could significantly promote the expression of Wnt noncanonical signaling pathways ligands in nasopharyngeal carcinoma, among which Wnt5A was the most markedly altered. We have demonstrated that Wnt5a can reduce the radiation sensitivity of nasopharyngeal carcinoma in vitro and in vitro experiments. Meanwhile, we found much more greater autophagosomes in overexpressed-Wnt5A nasopharyngeal carcinoma cells by electron microscopy. Further mechanism exploration revealed that Beclin1 is the main target of Wnt5A, and knocking down Beclin1 can partially reduce Wnt5a-induced radiation resistance. By studying Wnt5A-mediated protective autophagy in promoting radiation resistance in nasopharyngeal carcinoma cells, we hope that the Wnt5A and Beclin1 can become effective targets for overcoming radiation resistance in the future.

WNT11, a new gene associated with early-onset osteoporosis, is required for osteoblastogenesis

Monogenic early-onset osteoporosis (EOOP) is a rare disease defined by low bone mineral density (BMD) that results in increased risk of fracture in children and young adults. Although several causative genes have been identified, some of the EOOP causation remains unresolved. Whole-exome sequencing revealed a de novo heterozygous loss-of-function mutation in WNT11 (NM_004626.2:c.677_678dup p.Leu227Glyfs*22) in a 4-year-old boy with low BMD and fractures. We identified two heterozygous WNT11 missense variants (NM_004626.2:c.217G > A p.Ala73Thr) and (NM_004626.2:c.865G > A p.Val289Met) in a 51-year-old woman and in a 61-year-old woman respectively, both with bone fragility. U2OS cells with heterozygous WNT11 mutation (NM_004626.2:c.690_721delfs*40) generated by CRISPR-Cas9 showed reduced cell proliferation (30%) and osteoblast differentiation (80%) as compared with wild-type U2OS cells. The expression of genes in the Wnt canonical and non-canonical pathways was inhibited in these mutant cells, but recombinant WNT11 treatment rescued the expression of Wnt pathway target genes. Furthermore, the expression of RSPO2, a WNT11 target involved in bone cell differentiation, and its receptor LGR5, was decreased in WNT11 mutant cells. Treatment with WNT5A and WNT11 recombinant proteins reversed LGR5 expression, but WNT3A recombinant protein treatment had no effect on LGR5 expression in mutant cells. Moreover, treatment with recombinant RSPO2 but not WNT11 or WNT3A activated the canonical pathway in mutant cells. In conclusion, we have identified WNT11 as a new gene responsible for EOOP, with loss-of-function variant inhibiting bone formation via Wnt canonical and non-canonical pathways. WNT11 may activate Wnt signaling by inducing the RSPO2-LGR5 complex via the non-canonical Wnt pathway.

Targeting STAT3 prevents bile reflux-induced oncogenic molecular events linked to hypopharyngeal carcinogenesis

The signal transducer and activator of transcription 3 (STAT3) oncogene is a transcription factor with a central role in head and neck cancer. Hypopharyngeal cells (HCs) exposed to acidic bile present aberrant activation of STAT3, possibly contributing to its oncogenic effect. We hypothesized that STAT3 contributes substantially to the bile reflux‐induced molecular oncogenic profile, which can be suppressed by STAT3 silencing or pharmacological inhibition. To explore our hypothesis, we targeted the STAT3 pathway, by knocking down STAT3 (STAT3 siRNA), and inhibiting STAT3 phosphorylation (Nifuroxazide) or dimerization (SI3‐201; STA‐21), in acidic bile (pH 4.0)‐exposed human HCs. Immunofluorescence, luciferase assay, Western blot, enzyme‐linked immunosorbent assay and qPCR analyses revealed that STAT3 knockdown or pharmacologic inhibition significantly suppressed acidic bile‐induced STAT3 activation and its transcriptional activity, Bcl‐2 overexpression, transcriptional activation of IL6, TNF‐α, BCL2, EGFR, STAT3, RELA(p65), REL and WNT5A, and cell survival. Our novel findings document the important role of STAT3 in bile reflux‐related molecular oncogenic events, which can be dramatically prevented by STAT3 silencing. STA‐21, SI3‐201 or Nifuroxazide effectively inhibited STAT3 and cancer‐related inflammatory phenotype, encouraging their single or combined application in preventive or therapeutic strategies of bile reflux‐related hypopharyngeal carcinogenesis.

P-Cadherin and WNT5A expression in assessment of lymph node metastasis in oral squamous cell carcinoma

BACKGROUND

Oral cancer progression is a multi-step process in which adhesion molecules play a pivotal role in the development of recurrent, invasive, and distant metastasis. The aim of this study was to adopt prognostic biomarkers to assess the lymph node metastasis of OSCC that will facilitate in deciding the treatment modality by the surgeons.

OBJECTIVES

The objectives of the study were to assess the biological behaviour of OSCC by correlating the expression levels of P-Cadherin and WNT5A immunohistochemically.

METHODS

A total of 60 selected OSCCs cases (lymph node metastasis n = 30, non-metastatic n = 30) and 10 normal healthy controls were quantitatively and qualitatively analysed by immunohistochemistry for P-Cadherin and WNT5A. A survival analysis was also performed.

RESULTS

The expression levels of P-Cadherin and WNT5A in OSCC groups were statistically significant between metastatic and non-metastatic groups (p < 0.001). P-Cadherin and WNT5A expression in metastatic (lymph node metastasis) and non-metastatic cases showed a significant correlation coefficient of 0.753 at (p < 0.01). The present study also found that the aberrant expression (high) of P-Cadherin was associated with diminished survival of patients with metastatic OSCC.

CONCLUSION

The present study demonstrated the aberrant expression of P-Cadherin and WNT5A could serve as important prognosticator in OSCC.

CLINICAL RELEVANCE

P-Cadherin and WNT5A could be used as significant predictors of disease outcome.

Celastrol Attenuates Lipid Accumulation and Stemness of Clear Cell Renal Cell Carcinoma via CAV-1/LOX-1 Pathway

Clear cell renal cell carcinoma (ccRCC) is characterized by abnormal lipid accumulation. Celastrol is a pentacyclic triterpene extracted from Tripterygium wilfordii Hook F with anti-cancer activity. In the present study, the anticancer effects of celastrol on ccRCC and the underlying mechanisms were studied. Patients with reduced high density lipoprotein (HDL) and elevated levels of triglyceride (TG), total cholesterol (TC), low density lipoprotein (LDL) was found to have higher risk of ccRCC. In ccRCC clinical samples and cell lines, caveolin-1 (CAV-1) was highly expressed. CAV-1 was identified as a potential prognostic biomarker for ccRCC. Celastrol inhibited tumor growth and decreased lipid deposition promoted by high-fat diet in vivo. Celastrol reduced lipid accumulation and caveolae abundance, inhibited the binding of CAV-1 and lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) in ccRCC cells. Furthermore, celastrol attenuated stemness through blocking Wnt/β-catenin pathway after knockdown of CAV-1 and LOX-1. Therefore, the findings suggest that celastrol may be a promising active ingredient from traditional Chinese medicine for anti-cancer therapy.

Circ-ZFR Promotes Progression of Bladder Cancer by Upregulating WNT5A Via Sponging miR-545 and miR-1270

Background

Bladder cancer is one of the most common cancers all over the world. CircZFR is a circular RNA and has been implicated in tumor generation and invasion. However, the exact role of circZFR in the development of bladder cancer (BCa) remains unknown. This study aimed to investigate the function of circZFR in BCa, and further to probe into the association between circ-ZFR, miR-545/miR-1270 and WNT5A.

Methods

The expression of circZFR in BCa was quantified by qRT-PCR and was positively correlated with the prognosis of BCa patients. Next, the stable knockdown of circZFR BCa cell lines was established and the resulting capacities of proliferation, migration and invasion were measured. The association of circZFR with miR-1270/miR-545 was predicted by circinteractome prediction, and was confirmed by luciferase assay as well as RNA pull down assay. Furthermore, miRNA inhibitors, WNT5A overexpression and Pearson correlation analysis were used to examine the relationship between circZFR, miR-1270/miR-545 and WNT5A.

Results

The expression of CircZFR was up-regulated both in BCa tissues and in BCa cell lines, and was positively correlated with patient survival rates. Blocking of circZFR's expression by RNA inhibitors suppressed the proliferation, migration and invasion of BCa cells both in vitro and in vivo. On the other hand, overexpression of target miRNA supported that circZFR directly interact with miR-545 and miR-1270. Moreover, we demonstrated that circZFR promotes the progression of BCa by upregulating WNT5A's expression via sponging miR-545 and miR-1270.

Conclusions

CircZFR promotes the proliferation, migration and invasion of BCa cells by upregulating WNT5A signaling pathway via sponging miR-545 and miR-1270. These results provide new insights into the molecular mechanism of circZFR in BCa progression, and more important, a novel target for BCa clinical treatment.

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.

miR‑576‑5p promotes epithelial‑to‑mesenchymal transition in colorectal cancer by targeting the Wnt5a‑mediated Wnt/β‑catenin signaling pathway

Colorectal cancer (CRC) is one of the most common types of malignancy and the third most commonly diagnosed form of cancer worldwide, ranking as the fourth leading cause of cancer‑associated mortality. MicroRNA (miR)‑576‑5p has been reported to be highly expressed in patients with CRC; however, its biological role remains unclear. The present study aimed therefore to investigate the biological role and underlying mechanism of miR‑576‑5p in CRC cell line SW480. The viability of SW480 cells following transfection with miR‑576‑5p mimic or inhibitor was analyzed using MTT assay. Wound healing and Transwell assays were performed to determine the cell migratory and invasive abilities, respectively. A dual luciferase reporter assay was used to verify the predicted binding site between miR‑576‑5p and Wnt5a. Reverse transcription‑quantitative PCR and western blotting were used to analyze the expression levels of miR‑576‑5p, E‑cadherin, N‑cadherin, vimentin, Snail1, Wnt5a, β‑catenin, c‑myc, cyclin D1 and p/t‑c‑Jun. Using bioinformatics analysis, high expression of miR‑576‑5p was found not only in tumor tissues, compared with the normal tissue, but also in CRC cells, compared with NCM460 cells. Furthermore, the inhibition of miR‑576‑5p expression significantly decreased the cell viability and the migratory and invasive abilities of SW480 cells, and suppressed the epithelial‑to‑mesenchymal transition (EMT). In addition, miR‑576‑5p could interact with Wnt5a and regulate the expression level of Wnt5a in order to influence the activity of Wnt/β‑catenin signaling. The results from rescue experiments further demonstrated that the effect of miR‑576‑5p overexpression on cell metastasis and EMT was reversed by Wnt5a overexpression or treatment with XAV‑939, which is an inhibitor of the Wnt/β‑catenin signaling pathway. In conclusion, the findings from the present study suggested that inhibition of miR‑576‑5p may suppress SW480 cell metastasis and EMT by targeting Wnt5a and regulating the Wnt5a‑mediated Wnt/β‑catenin signaling pathway, providing a potential therapeutic target for the treatment of CRC.

Role of Wnt5a in suppressing invasiveness of hepatocellular carcinoma via epithelial-mesenchymal transition

Inappropriate activation of the canonical Wnt signaling pathway is associated with progression of hepatocellular carcinoma (HCC). However, the association between the non-canonical pathway activated by Wnt5a and HCC is not well known. The present study investigated the significance of Wnt5a expression in HCC. Immunohistochemical staining of Wnt5a was performed on specimens from 243 patients who underwent hepatic resection for HCC. The present study investigated whether Wnt5a expression was associated with clinical and pathological factors and prognosis. Wnt5a expression in human HCC cell lines was investigated using western blotting. The effects of overexpression or knockdown of Wnt5a were evaluated using proliferation and invasion assays. Changes in epithelial-mesenchymal transition (EMT)-related molecules were investigated using western blotting. Wnt5a negativity was significantly associated with poor tumor differentiation and positive vascular invasion. In univariate analysis, Wnt5a negativity was identified as a significant prognostic factor for overall survival (OS). Multivariate analysis of OS demonstrated that Wnt5a negativity was an independent prognostic factor. Wnt5a expression was lower in HLE and HLF cells than in HepG2 and Huh7 cells. Knockdown of Wnt5a by short hairpin RNA transfection increased the proliferation and invasiveness of Huh7 cells, and decreased the expression levels of E-cadherin. In HLF cells, overexpression of Wnt5a inhibited invasiveness and decreased the expression levels of vimentin. Wnt5a negativity was associated with poor tumor differentiation and positive vascular invasion, and was an independent poor prognostic factor in patients with HCC. Wnt5a may be a tumor suppressor involved in EMT-mediated changes in invasiveness.

Non-Canonical WNT5A Signaling Through RYK Contributes to Aggressive Phenotype of the Rheumatoid Fibroblast-Like Synoviocytes

We hypothesized that WNT5A could contribute to the enhanced migration and invasiveness of rheumatoid arthritis fibroblast-like synoviocytes (RA FLS), which is one of the incompletely understood aspects of the RA FLS aggressive phenotype. This hypothesis is based on the previous evidence of a WNT5A role in both, RA and cell migration. Migration and invasion of RA FLS were assessed after incubation with recombinant Wnt5a (rWnt5a) or silencing of the endogenous WNT5A expression. The expression of WNT5A, WNT receptors, cytokines, chemokines, and metalloproteinases was quantified with RT-PCR. The WNT pathway was explored with gene silencing, antibody and pharmacological inhibition followed by migration assays and phosphoprotein western blots. Here, we reported that rWnt5a promoted migration and invasion of RA FLS, whereas knockdown of the endogenous WNT5A reduced them. These effects were specific to the RA FLS since they were not observed in FLS from osteoarthritis (OA) patients. Also, rWnt5a induced the expression of IL6, IL8, CCL2, CXCL5, MMP1, MMP3, MMP9, and MMP13 from baseline or potentiating the TNF induction, WNT5A signaling required the RYK receptor and was mediated through the WNT/Ca²⁺ and the ROCK pathway. These pathways involved the RYK and ROCK dependent activation of the p38, ERK, AKT, and GSK3β kinases, but not the activation of JNK. Together these findings indicate that WNT5A contributes to the enhanced migration and invasiveness of RA FLS through RYK and the specific activation of ROCK and downstream kinases.

Steroid receptor RNA activator inhibits the migration, invasion and stemness characteristics of renal cell carcinoma cells

Renal cell carcinoma (RCC) has a high mortality rate among urological malignancies, and its underlying mechanisms remain unclear. Steroid receptor RNA coactivator (SRA) belongs to the long non-coding RNAs (lncRNAs) and has been demonstrated to be closely related to various types of cancer. In the present study, the decreased expression level of SRA was first confirmed in RCC tissues and cell lines by RT-qPCR. Using knockdown or overexpression systems, it was then found that SRA inhibited the proliferation of RCC cell lines and promoted their apoptosis. In addition, SRA suppressed the migration and invasion, and altered EMT-related markers in RCC cells. More importantly, it was demonstrated that SRA reduced percentage of CD44⁺/CD24⁻ cells and the sphere-forming efficiency. SRA also attenuated the expression levels of CD44, SOX-2, ABCG2 and OCT-4, which are all associated with cancer cell stemness characteristics. Although SRA increased the phosphorylation of extracellular-regulated protein kinase (ERK), the ERK1/2 pathway could not further interfere with the alteration of EMT-related markers mediated by SRA. Notably, the ERK inhibitor, PD98059, abolished ERK1/2 phosphorylation, whereas it did not exert any marked effects on cell proliferation and EMT-related markers mediated by SRA. Taken together, the findings of the present study indicate that SRA is an important molecule that inhibits the migration, invasion and stem cell characteristics of RCC cells; the ERK signaling pathway may not be involved in this process.

Chemotherapy and chemo-resistance in nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is closely associated with Epstein-Barr virus (EBV) and occurs frequently in the south of China and Southeast Asian countries. Concurrent chemo-radiotherapy is one of the main treatments for NPC. Although, the combined treatment of chemo-radiotherapy produces a satisfying survival rate, the chemo-resistance arises as a big obstacle in curing recurrent NPC patients. The acquirement of chemo-resistance is usually along with a poor prognosis. So far, the mechanism of chemo-resistance in NPC has not been fully elucidated and there have not been a comprehensive review on this issue. Thus, it is of great significance to summarize the mechanisms involved in NPC chemo-resistance. In this review, the importance and limitations of chemotherapy and the mechanisms of chemo-resistances in NPC were discussed.

Non-canonical WNT5a regulates Epithelial-to-Mesenchymal Transition in the mouse ovarian surface epithelium

The ovarian surface epithelium (OSE) is a monolayer that covers the ovarian surface and is involved in ovulation by rupturing and enabling release of a mature oocyte and by repairing the wound after ovulation. Epithelial-to-mesenchymal transition (EMT) is a mechanism that may promote wound healing after ovulation. While this process is poorly understood in the OSE, in other tissues wound repair is known to be under the control of the local microenvironment and different growth factors such as the WNT signaling pathway. Among WNT family members, WNT4 and WNT5a are expressed in the OSE and are critical for the ovulatory process. The objective of this study was to determine the potential roles of WNT4 and WNT5a in regulating the OSE layer. Using primary cultures of mouse OSE cells, we found WNT5a, but not WNT4, promotes EMT through a non-canonical Ca2+-dependent pathway, up-regulating the expression of Vimentin and CD44, enhancing cell migration, and inhibiting the CTNNB1 pathway and proliferation. We conclude that WNT5a is a stimulator of the EMT in OSE cells, and acts by suppressing canonical WNT signaling activity and inducing the non-canonical Ca2+ pathway.

Wnt5a/Ror2 pathway contributes to the regulation of cholesterol homeostasis and inflammatory response in atherosclerosis

Atherosclerosis (AS) is characterized by lipids metabolism disorder and inflammatory response. Accumulating evidence has demonstrated that Wingless type 5a (Wnt5a) is implicated in cardiovascular diseases through non-canonical Wnt cascades. However, its precise role during the pathogenesis of AS is still unclear. Therefore, the present study aims to investigate the role and the underlying mechanism of Wnt5a/receptor tyrosine kinase-like orphan receptor 2 (Ror2) pathways in the promotion of AS process through affecting lipid accumulation and inflammation. In atherosclerotic clinical samples, Wnt5a levels were measured by using enzyme-linked immunosorbent assay (ELISA) assay. In vivo experiments were conducted by using apolipoprotein E knockout (apoE^-/-) mice model. Vascular smooth muscle cells (VSMCs) were applied for in vitro studies. Wnt5a was highly expressed in both of atherosclerotic clinical samples and apoE^-/- mice. The knockdown of Wnt5a significantly inhibited cholesterol accumulation and inflammatory response. Additionally, the lipopolysaccharide (LPS)-induced inflammation aggravated the cholesterol accumulation and decreased adenosine triphosphate (ATP)-binding cassette transporter A1 (ABCA1) expression in VSMCs. Depletion of intracellular cholesterol by β-cyclodextrin (β-CD) led to the upregulation of ABCA1 and the inhibition of inflammation. Conversely, the overexpression of Wnt5a inhibited ABCA1 expression, facilitated cholesterol accumulation, impared cholesterol efflux, promoted NF-κB nuclear translocation and the inflammatory cytokines secretion. Moreover, the knockdown of Ror2 increased ABCA1 expression and reduced Wnt5a-induced cholesterol accumulation and inflammatory responses. Furthermore, the knockdown of ABCA1 enhanced cholesterol accumulation and inflammatory response. Therefore, Wnt5a/Ror2 pathway was critical in regulating cholesterol homeostasis and inflammatory response, which might be a promising therapeutic target for AS therapy.

Identification of candidate genes of nasopharyngeal carcinoma by bioinformatical analysis

OBJECTIVE

This study aimed to identify candidate genes as potential biomarkers in nasopharyngeal carcinoma (NPC) by bioinformatical analysis.

METHODS

Three microarray datasets: GSE32906, GSE15170, GSE53819 were download from public database and analyzed to identify the differentially expressed genes (DEGs) between NPC and normal samples. Functional and pathway enrichment analysis of the DEGs were performed. Protein-protein interaction network and gene-transcription factor regulatory network of DEGs were constructed. And the expression of hub genes in NPC was also validated based on the public database.

RESULTS

A total of 16 up-regulated and 27 down-regulated genes were screened out from the microarray datasets. Functional and pathway enrichment analysis showed that DEGs were mostly enriched in positive regulation of angiogenesis, mesenchymal cell proliferation, cell surface and DNA binding, ECM-receptor interaction pathway, PI3K-Akt signaling pathway, and pathways in cancer. Five hub genes JUN, VEGFA, FOXM1, MYB, and WNT5A were identified from the protein-protein interaction network. Subsequently, the hub gene-transcription factor regulatory network revealed that STAT3, MYC, SOX2, RUNX2 present key relations with hub genes. The expression of these five hub genes were also validated to be differentially expressed among NPC and normal samples.

CONCLUSIONS

The current study indicated that the hub DEGs JUN, VEGFA, FOXM1, MYB, and WNT5A we identified might be potential therapeutic biomarkers of NPC.

Annexin A2 interacting with ELMO1 regulates HCC chemotaxis and metastasis. Life Sci. 2019;222:168-174. [PMID: 30853625 DOI: 10.1016/j.lfs.2019.03.003]

AIMS

SDF-1α induced chemotaxis plays an important role in hepatocellular carcinoma metastasis. CXCR4 stimulated by SDF-1α/CXCL12 triggers heterotrimeric G proteins activation, which regulate migration and chemotaxis of hepatocellular carcinoma cells. The pathways linking the chemokine GPCR/Gi signaling to actin polymerization for migration of cancer cells are not known.

MATERIALS AND METHODS

Through would healing assay, chemotaxis assay, F-actin polymerization assay, confocal assay, immunohistochemical assay, protein identification and coimmunoprecipitation assay, we detected the role and mechanisms of Annexin A2 in hepatocellular carcinoma.

KEY FINDINGS

In the present study, we firstly investigated the role of Annexin A2 in HepG2 cell chemotaxis and metastasis. Immunohistochemical analysis showed that Annexin A2 was highly expressed in hepatocellular carcinoma tissues. Its expression was closely associated with lymph node and distant metastasis. Knockdown Annexin A2 impaired cancer cell chemotaxis. Co-immunoprecipitation results showed an interaction between Annexin A2 and ELMO1. CXCL12 triggers an ELMO1-dependent membrane translocation of Annexin A2.

SIGNIFICANCE

Taken together, our results indicated an important role of Annexin A2 in hepatocellular carcinoma tissues metastasis and revealed a novel molecular mechanism of its activation.

Frizzled 2-induced epithelial-mesenchymal transition correlates with vasculogenic mimicry, stemness, and Hippo signaling in hepatocellular carcinoma

Prior observation has indicated that Frizzled 2 (FZD2)‐induced epithelial‐mesenchymal transition (EMT) could be a key step in metastasis and early recurrence of hepatocellular carcinoma (HCC). However, the mechanism underlying tumor development and progression due to aberrant FZD2 expression is poorly defined. Here, we provide evidence that FZD2 is a driver for EMT, cancer stem cell properties, and vasculogenic mimicry (VM) in HCC. We found that FZD2 was highly expressed in two cohorts of Chinese hepatitis B virus‐related HCC patients, and that high FZD2 expression was associated with poor prognosis. Concerning the mechanism, gain‐ and loss‐of‐function experiments showed the oncogenic action of FZD2 in HCC cell proliferation, apoptosis, migration, and invasion. Further investigations in vitro and in vivo suggested that FZD2 promotes the EMT process, enhances stem‐like properties, and confers VM capacity to HCC cells. Notably, integrative RNA sequencing analysis of FZD2‐knockdown cells indicated the enrichment of Hippo signaling pathway. Taken together, our data suggest for the first time that FZD2 could promote clinically relevant EMT, CD44⁺ stem‐like properties, and the VM phenotype in HCC involving a potential Hippo signaling pathway‐dependent mechanism, and should be considered as a promising therapeutic target for the treatment of HCC.

Long non-coding RNA-SRA promotes neointimal hyperplasia and vascular smooth muscle cells proliferation via MEK-ERK-CREB pathway

Long noncoding RNA-steroid receptor RNA activator (LncRNA-SRA) is transcribed from a class of noncoding genes, and plays a critical role in regulating cell proliferation. However, the effect of lncRNA-SRA remains unclear in vascular proliferative diseases. In the present study, we overexpressed lncRNA-SRA in vitro, then investigated the biological consequences. A vascular damage mice model was constructed by performing femoral artery wire injury. LncRNA-SRA was overexpressed in the injured arteries, and significantly promoted the expression of ki67, thereby caused an overall increase in neointima formation. LncRNA-SRA overexpression led to the proliferation and migration of vascular smooth muscle cells (VSMCs). By stimulating the phosphorylation of MEK, ERK and CREB (cyclic nucleotide responsive element binding protein), lncRNA-SRA promoted VSMC proliferation. Meanwhile, these effects were blocked by the MEK inhibitor U0126. Therefore, lncRNA-SRA promoted VSMC proliferation by activating the MEK-ERK-CREB pathway. LncRNA-SRA could be a promising therapeutic target in vascular diseases characterized by neointimal hyperplasia.

TET1 exerts its anti-tumor functions via demethylating DACT2 and SFRP2 to antagonize Wnt/β-catenin signaling pathway in nasopharyngeal carcinoma cells

BACKGROUND

TET1 is a tumor suppressor gene (TSG) that codes for ten-eleven translocation methyl cytosine dioxygenase1 (TET1) catalyzing the conversion of 5-methylcytosine to 5-hydroxy methyl cytosine as a first step of TSG demethylation. Its hypermethylation has been associated with cancer pathogenesis. However, whether TET1 plays any role in nasopharyngeal carcinoma (NPC) remains unclear. This study investigated the expression and methylation of TET1 in NPC and confirmed its role and mechanism as a TSG.

RESULTS

TET1 expression was downregulated in NPC tissues compared with nasal septum deviation tissues. Demethylation of TET1 in HONE1 and HNE1 cells restored its expression with downregulated methylation, implying that TET1 was silenced by promoter hypermethylation. Ectopic expression of TET1 suppressed the growth of NPC cells, induced apoptosis, arrested cell division in G0/G1 phase, and inhibited cell migration and invasion, confirming TET1 TSG activity. TET1 decreased the expression of nuclear β-catenin and downstream target genes. Furthermore, TET1 could cause Wnt antagonists (DACT2, SFRP2) promoter demethylation and restore its expression in NPC cells.

CONCLUSIONS

Collectively, we conclude that TET1 exerts its anti-tumor functions in NPC cells by suppressing Wnt/β-catenin signaling via demethylation of Wnt antagonists (DACT2 and SFRP2).

Wnt5a and CCL25 promote adult T-cell acute lymphoblastic leukemia cell migration, invasion and metastasis

Adult T-cell acute lymphoblastic leukemia (T-ALL) is a refractory leukemia. We previously showed that CCL25/CCR9 promotes T-ALL metastasis. In the present study, we assessed the effects of CCL25 on Wnt expression and the effects of Wnt5a and CCL25 on PI3K/Akt and RhoA activation. Transwell assays and mouse xenograft experiments were utilized to assess the effects of Wnt5a and CCL25 on MOLT4 cell invasion, migration and metastasis. The effects of Wnt5a on MOLT4 cell actin polarization and pseudopodium formation were examined using laser scanning confocal microscopy and scanning electron microscopy. CCL25 induced Wnt5a expression in MOLT4 cells by promoting protein kinase C (PKC) expression and activation. Wnt5a promoted MOLT4 cell migration, invasion, actin polarization, and lamellipodium and filopodia formation via PI3K/Akt-RhoA pathway activation. These effects were rescued by PI3K/Akt or RhoA knockdown or inhibition. Additionally, Wnt5a in cooperation with CCL25 promoted MOLT4 cell mouse liver metastasis and stimulated RhoA activation. These results show that CCL25/CCR9 upregulates Wnt5a by promoting PKC expression and activation in MOLT4 cells. This in turn promotes cell migration and invasion via PI3K/Akt-RhoA signaling, enhancing cell polarization and pseudopodium formation. These findings indicate that the PI3K/Akt-RhoA pathway is likely responsible for Wnt5a-induced adult T-ALL cell migration and invasion.

miR-129-5p targets Wnt5a to block PKC/ERK/NF-κB and JNK pathways in glioblastoma

Therapeutic application of microRNAs (miRNAs) in Wnt-driven glioma has been valuable; however, their specific roles and mechanisms have not been completely investigated. Real-time quantitative PCR (RT-qPCR) was used to analyse the expression of microRNA-129-5p (miR-129-5p) in human glioma samples. Cell-Counting Kit 8 (CCK-8), flow cytometry, EdU, angiogenesis, Transwell invasion, wound healing, in vitro 3D migration and neurosphere formation assays were employed to assess the role of miR-129-5p in glioblastoma multiforme (GBM) cells. Moreover, we performed the luciferase reporter assay and the RNA-ChIP (chromatin immunoprecipitation) assay to confirm whether Wnt5a was a direct target of miR-129-5p. We also confirmed the correlation between the expression profile of miR-129-5p and Wnt5a in glioma patients from the Chinese Glioma Genome Atlas (CGGA) and investigated the overall survival of GBM patients using two data sets, namely, TCGA and GSE16011, according to their Wnt5a expression status. MiR-129-5p expression levels were downregulated and inversely correlated with Wnt5a expression levels in CGGA glioma patients. Restored expression of miR-129-5p blocked GBM cell proliferation, invasion, migration, angiogenesis, neurosphere formation and resistance to temozolomide. We reported that miR-129-5p directly targeted Wnt5a in glioma. Furthermore, we observed that overexpression of miR-129-5p inhibited the expression of Wnt5a, thus blocking the protein kinase C(PKC)/ERK/NF-κB and JNK pathways. Inhibiting Wnt5a rescued the effects of miR-129-5p loss and increased Wnt5a expression was associated with reduced overall survival of GBM patients. We also demonstrated the inhibitory effect of miR-129-5p on tumour growth in GBM using an in vivo model. The miR-129-5p/Wnt5a-axis-mediated PKC/ERK/NF-κB and JNK pathways have therapeutic potential in GBM treatment.

NTS/NTR1 co-expression enhances epithelial-to-mesenchymal transition and promotes tumor metastasis by activating the Wnt/β-catenin signaling pathway in hepatocellular carcinoma

Neurotensin (NTS) is a neuropeptide distributed in central nervous and digestive systems. In this study, the significant association between ectopic NTS expression and tumor invasion was confirmed in hepatocellular carcinoma (HCC). In primary HCC tissues, the NTS and neurotensin receptor 1 (NTR1) co-expression (NTS⁺NTR1⁺) is a poor prognostic factor correlated with aggressive biological behaviors and poor clinical prognosis. Enhanced epithelial-to-mesenchymal transition (EMT) features, including decreased E-cadherin, increased β-catenin translocation and N-cadherin expression, were identified in NTS⁺NTR1⁺ HCC tissues. Varied NTS-responsible HCC cell lines were established using NTR1 genetically modified Hep3B and HepG2 cells which were used to elucidate the molecular mechanisms regulating NTS-induced EMT and tumor invasion in vitro. Results revealed that inducing exogenous NTS stimulation and enhancing NTR1 expression promoted tumor invasion rather than proliferation by accelerating EMT in HCC cells. The NTS-induced EMT was correlated with the remarkable increase in Wnt1, Wnt3, Wnt5, Axin, and p-GSK3β expression and was significantly reversed by blocking the NTS signaling via the NTR1 antagonist SR48692 or by inhibiting the activation of the Wnt/β-catenin pathway via specific inhibitors, such as TSW119 and DKK-1. SR48692 also inhibited the metastases of NTR1-overexpressing HCC xenografts in the lungs in vivo. This finding implied that NTS may be an important stimulus to promote HCC invasion and metastasis both in vitro and in vivo, and NTS signaling enhanced the tumor EMT and invasion potentials by activating the canonical Wnt/β-catenin signaling pathway. Therefore, NTS may be a valuable therapeutic target to prevent tumor progression in HCC.

CFTR is a potential marker for nasopharyngeal carcinoma prognosis and metastasis

While there is an increasing interest in the correlation of cystic fibrosis transmembrane conductance regulator (CFTR) and cancer incidence, the role of CFTR in nasopharyngeal carcinoma (NPC) development remains unknown. In this study, we aimed to explore the prognostic value of CFTR in NPC patients. The expression of CFTR was determined in NPC cell lines and tissues. Statistical analysis was utilized to evaluate the correlation between CFTR expression levels and clinicopathological characteristics and prognosis in 225 cases of NPC patients. The results showed that CFTR was down-regulated in NPC tissues and cell lines. Low expression of CFTR was correlated with advanced stage (p = 0.026), distant metastasis (p < 0.001) and poor prognosis (p < 0.01). Multivariate analysis identified CFTR as an independent prognostic factor (p = 0.003). Additionally, wound healing and transwell assays revealed that overexpression of CFTR inhibited NPC cell migration and invasion, whereas knockdown of CFTR promoted cell migration and invasion. Thus, the current study indicates that CFTR, as demonstrated to play an important role in tumor migration and invasion, may be used as a potential prognostic indicator in NPC.

PDGFRα depletion attenuates glioblastoma stem cells features by modulation of STAT3, RB1 and multiple oncogenic signals

Platelet derived growth factor receptors (PDGFRs) play an important role in tumor pathogenesis, and they are frequently overexpressed in glioblastoma (GBM). Earlier we have shown a higher protein expression of PDGFR isoforms (α and β) in peritumoral-tissue derived cancer stem cells (p-CSC) than in tumor core (c-CSC) of several GBM affected patients. In the current study, in order to assess the activity of PDGFRα/PDGF-AA signaling axis, we performed time course experiments to monitor the effects of exogenous PDGF-AA on the expression of downstream target genes in c-CSC vs p-CSC. Interestingly, in p-CSC we detected the upregulation of Y705-phosphorylated Stat3, concurrent with a decrement of Rb1 protein in its active state, within minutes of PDGF-AA addition. This finding prompted us to elucidate the role of PDGFRα in self-renewal, invasion and differentiation in p-CSC by using short hairpin RNA depletion of PDGFRα expression. Notably, in PDGFRα-depleted cells, protein analysis revealed attenuation of stemness-related and glial markers expression, alongside early activation of the neuronal marker MAP2a/b that correlated with the induction of tumor suppressor Rb1. The in vitro reduction of the invasive capacity of PDGFRα-depleted CSC as compared to parental cells correlated with the downmodulation of markers of epithelial-mesenchymal transition phenotype and angiogenesis. Surprisingly, we observed the induction of anti-apoptotic proteins and compensatory oncogenic signals such as EDN1, EDNRB, PRKCB1, PDGF-C and PDGF-D. To conclude, we hypothesize that the newly discovered PDGFRα/Stat3/Rb1 regulatory axis might represent a potential therapeutic target for GBM treatment.

Epstein-Barr virus stably confers an invasive phenotype to epithelial cells through reprogramming of the WNT pathway

Epstein-Barr virus (EBV)-associated carcinomas, such as nasopharyngeal carcinoma (NPC), exhibit an undifferentiated and metastatic phenotype. To determine viral contributions involved in the invasive phenotype of EBV-associated carcinomas, EBV-infected human telomerase-immortalized normal oral keratinocytes (NOK) were investigated. EBV-infected NOK were previously shown to undergo epigenetic reprogramming involving CpG island hypermethylation and delayed responsiveness to differentiation. Here, we show that EBV-infected NOK acquired an invasive phenotype that was epigenetically retained after viral loss. The transcription factor lymphoid enhancer factor 1 (LEF1) and the secreted ligand WNT5A, expressed in NPC, were increased in EBV-infected NOK with sustained expression for more than 20 passages after viral loss. Increased LEF1 levels involved four LEF1 variants, and EBV-infected NOK showed a lack of responsiveness to β-catenin activation. Although forced expression of WNT5A and LEF1 enhanced the invasiveness of parental NOK, LEF1 knockdown reversed the invasive phenotype of EBV-infected NOK in the presence of WNT5A. Viral reprogramming of LEF1 and WNT5A was observed several passages after EBV infection, suggesting that LEF1 and WNT5A may provide a selective advantage to virally-infected cells. Our findings suggest that EBV epigenetically reprogrammed epithelial cells with features of basal, wound healing keratinocytes, with LEF1 contributing to the metastatic phenotype of EBV-associated carcinomas.

ISG15 predicts poor prognosis and promotes cancer stem cell phenotype in nasopharyngeal carcinoma

Interferon-stimulated gene 15 (ISG15), the first identified ubiquitin-like protein, is known for its anti-viral capacity. However, its role in tumorigenesis remains controversial. Here, using RNA-seq profiling analysis, we identified ISG15 as a differentially expressed gene in nasopharyngeal carcinoma (NPC) and validated its overexpression in NPC samples and cells. High ISG15 levels in NPC tissues were correlated with more frequent local recurrence and shorter overall survival and disease-free survival. ISG15 overexpression promoted a cancer stem cell phenotype in NPC cells, including increased colony and tumorsphere formation abilities, pluripotency-associated genes expression, and in vivo tumorigenicity. By contrast, knockdown of ISG15 attenuated stemness characteristics in NPC cells. Furthermore, overexpression of ISG15 increased NPC cell resistance to radiation and cisplatin (DDP) treatment. Our study demonstrates a protumor role of ISG15, and suggests that ISG15 is a prognostic predictor and a potential therapeutic target for NPC.

Canonical and non-canonical WNT signaling in cancer stem cells and their niches: Cellular heterogeneity, omics reprogramming, targeted therapy and tumor plasticity (Review)

Cancer stem cells (CSCs), which have the potential for self-renewal, differentiation and de-differentiation, undergo epigenetic, epithelial-mesenchymal, immunological and metabolic reprogramming to adapt to the tumor microenvironment and survive host defense or therapeutic insults. Intra-tumor heterogeneity and cancer-cell plasticity give rise to therapeutic resistance and recurrence through clonal replacement and reactivation of dormant CSCs, respectively. WNT signaling cascades cross-talk with the FGF, Notch, Hedgehog and TGFβ/BMP signaling cascades and regulate expression of functional CSC markers, such as CD44, CD133 (PROM1), EPCAM and LGR5 (GPR49). Aberrant canonical and non-canonical WNT signaling in human malignancies, including breast, colorectal, gastric, lung, ovary, pancreatic, prostate and uterine cancers, leukemia and melanoma, are involved in CSC survival, bulk-tumor expansion and invasion/metastasis. WNT signaling-targeted therapeutics, such as anti-FZD1/2/5/7/8 monoclonal antibody (mAb) (vantictumab), anti-LGR5 antibody-drug conjugate (ADC) (mAb-mc-vc-PAB-MMAE), anti-PTK7 ADC (PF-06647020), anti-ROR1 mAb (cirmtuzumab), anti-RSPO3 mAb (rosmantuzumab), small-molecule porcupine inhibitors (ETC-159, WNT-C59 and WNT974), tankyrase inhibitors (AZ1366, G007-LK, NVP-TNKS656 and XAV939) and β-catenin inhibitors (BC2059, CWP232228, ICG-001 and PRI-724), are in clinical trials or preclinical studies for the treatment of patients with WNT-driven cancers. WNT signaling-targeted therapeutics are applicable for combination therapy with BCR-ABL, EGFR, FLT3, KIT or RET inhibitors to treat a subset of tyrosine kinase-driven cancers because WNT and tyrosine kinase signaling cascades converge to β-catenin for the maintenance and expansion of CSCs. WNT signaling-targeted therapeutics might also be applicable for combination therapy with immune checkpoint blockers, such as atezolizumab, avelumab, durvalumab, ipilimumab, nivolumab and pembrolizumab, to treat cancers with immune evasion, although the context-dependent effects of WNT signaling on immunity should be carefully assessed. Omics monitoring, such as genome sequencing and transcriptome tests, immunohistochemical analyses on PD-L1 (CD274), PD-1 (PDCD1), ROR1 and nuclear β-catenin and organoid-based drug screening, is necessary to determine the appropriate WNT signaling-targeted therapeutics for cancer patients.

Phosphorylation of Rab37 by protein kinase C alpha inhibits the exocytosis function and metastasis suppression activity of Rab37

We previously identified a novel Rab small GTPase protein, Rab37, which plays a critical role in regulating exocytosis of secreted glycoproteins, tissue inhibitor of metalloproteinases 1 (TIMP1) to suppress lung cancer metastasis. Patients with preserved Rab37 protein expression were associated with better prognosis. However, a significant number of the patients with preserved Rab37 expression showed poor survival. In addition, the molecular mechanism for the regulation of Rab37-mediated exocytosis remained to be further identified. Therefore, we investigated the molecular mechanism underlying the dysregulation of Rab37-mediated exocytosis and metastasis suppression. Here, we report a novel mechanism for Rab37 inactivation by phosphorylation. Lung cancer patients with preserved Rab37, low TIMP1, and high PKCα expression profile correlate with worse progression-free survival examined by Kaplan-Meier survival, suggesting that PKCα overexpression leads to dysfunction of Rab37. This PKCα-Rab37-TIMP1 expression profile predicts the poor outcome by multivariate Cox regression analysis. We also show that Rab37 is phosphorylated by protein kinase Cα (PKCα) at threonine 172 (T172), leading to attenuation of its GTP-bound state, and impairment of the Rab37-mediated exocytosis of TIMP1, and thus reduces its suppression activity on lung cancer cell motility. We further demonstrate that PKCα reduces vesicle colocalization of Rab37 and TIMP1, and therefore inhibits Rab37-mediated TIMP1 trafficking. Moreover, Phospho-mimetic aspartate substitution mutant T172D of Rab37 significantly promotes tumor metastasis in vivo. Our findings reveal a novel regulation of Rab37 activity by PKCα-mediated phosphorylation which inhibits exocytic transport of TIMP1 and thereby enhances lung tumor metastasis.

Novel chimeric transcript RRM2-c2orf48 promotes metastasis in nasopharyngeal carcinoma

Recently, chimeric transcripts have been found to be associated with the pathogenesis and poor prognosis of malignant tumors. Through our preliminary experiment, a novel chimeric transcript called chimeric transcript RRM2-c2orf48 was detected in C666-1, a classical cell line of human nasopharyngeal carcinoma (NPC). Therefore, the objective of this study was to demonstrate the existence and expression of novel chimeric transcript RRM2-c2orf48 and to explore the main functions and mechanisms of RRM2-c2orf48 in NPC. In this study, the expression of RRM2-c2orf48 was evaluated in NPC cells and specimens. Effects of RRM2-c2orf48 on migration and invasive capacities were detected invivo and vitro. Moreover, ways in which RRM2-c2orf48 increases the invasive capacities of NPC were explored. As a result, the presence of novel chimeric transcript RRM2-c2orf48 was confirmed in C666-1 by RT-PCR and sequencing, and it was a read-through between RRM2 and c2orf48 through the transcription of interchromosome. Higher expressions of novel RRM2-c2orf48 were detected in NPC cell lines and NPC tissue specimens relative to the controls and its expression was be statistically relevant to TNM staging. High level of RRM2-c2orf48 could increase the migration and invasive capacities of NPC cells, potentially as a result of NPC cell epithelial–mesenchymal transition. RRM2-c2orf48 could also enhance resistance of chemotherapy. In vivo, RRM2-c2orf48 could enhance lung and lymph node metastasis in nude mice. These results demonstrate that high levels of RRM2-c2orf48 expression may be a useful predictor of NPC patients of metastatic potency, presenting potential implications for NPC diagnosis and therapy.

Kinesin superfamily protein Kif26b links Wnt5a-Ror signaling to the control of cell and tissue behaviors in vertebrates

Wnt5a-Ror signaling constitutes a developmental pathway crucial for embryonic tissue morphogenesis, reproduction and adult tissue regeneration, yet the molecular mechanisms by which the Wnt5a-Ror pathway mediates these processes are largely unknown. Using a proteomic screen, we identify the kinesin superfamily protein Kif26b as a downstream target of the Wnt5a-Ror pathway. Wnt5a-Ror, through a process independent of the canonical Wnt/β-catenin-dependent pathway, regulates the cellular stability of Kif26b by inducing its degradation via the ubiquitin-proteasome system. Through this mechanism, Kif26b modulates the migratory behavior of cultured mesenchymal cells in a Wnt5a-dependent manner. Genetic perturbation of Kif26b function in vivo caused embryonic axis malformations and depletion of primordial germ cells in the developing gonad, two phenotypes characteristic of disrupted Wnt5a-Ror signaling. These findings indicate that Kif26b links Wnt5a-Ror signaling to the control of morphogenetic cell and tissue behaviors in vertebrates and reveal a new role for regulated proteolysis in noncanonical Wnt5a-Ror signal transduction.

WNT signaling - lung cancer is no exception

Since the initial discovery of the oncogenic activity of WNT ligands our understanding of the complex roles for WNT signaling pathways in lung cancers has increased substantially. In the current review, the various effects of activation and inhibition of the WNT signaling pathways are summarized in the context of lung carcinogenesis. Recent evidence regarding WNT ligand transport mechanisms, the role of WNT signaling in lung cancer angiogenesis and drug transporter regulation and the importance of microRNA and posttranscriptional regulation of WNT signaling are also reviewed.

Molecular genetics and targeted therapy of WNT-related human diseases (Review)

Canonical WNT signaling through Frizzled and LRP5/6 receptors is transduced to the WNT/β-catenin and WNT/stabilization of proteins (STOP) signaling cascades to regulate cell fate and proliferation, whereas non-canonical WNT signaling through Frizzled or ROR receptors is transduced to the WNT/planar cell polarity (PCP), WNT/G protein-coupled receptor (GPCR) and WNT/receptor tyrosine kinase (RTK) signaling cascades to regulate cytoskeletal dynamics and directional cell movement. WNT/β-catenin signaling cascade crosstalks with RTK/SRK and GPCR-cAMP-PKA signaling cascades to regulate β-catenin phosphorylation and β-catenin-dependent transcription. Germline mutations in WNT signaling molecules cause hereditary colorectal cancer, bone diseases, exudative vitreoretinopathy, intellectual disability syndrome and PCP-related diseases. APC or CTNNB1 mutations in colorectal, endometrial and prostate cancers activate the WNT/β-catenin signaling cascade. RNF43, ZNRF3, RSPO2 or RSPO3 alterations in breast, colorectal, gastric, pancreatic and other cancers activate the WNT/β-catenin, WNT/STOP and other WNT signaling cascades. ROR1 upregulation in B-cell leukemia and solid tumors and ROR2 upregulation in melanoma induce invasion, metastasis and therapeutic resistance through Rho-ROCK, Rac-JNK, PI3K-AKT and YAP signaling activation. WNT signaling in cancer, stromal and immune cells dynamically orchestrate immune evasion and antitumor immunity in a cell context-dependent manner. Porcupine (PORCN), RSPO3, WNT2B, FZD5, FZD10, ROR1, tankyrase and β-catenin are targets of anti-WNT signaling therapy, and ETC-159, LGK974, OMP-18R5 (vantictumab), OMP-54F28 (ipafricept), OMP-131R10 (rosmantuzumab), PRI-724 and UC-961 (cirmtuzumab) are in clinical trials for cancer patients. Different classes of anti-WNT signaling therapeutics are necessary for the treatment of APC/CTNNB1-, RNF43/ZNRF3/RSPO2/RSPO3- and ROR1-types of human cancers. By contrast, Dickkopf-related protein 1 (DKK1), SOST and glycogen synthase kinase 3β (GSK3β) are targets of pro-WNT signaling therapy, and anti-DKK1 (BHQ880 and DKN-01) and anti-SOST (blosozumab, BPS804 and romosozumab) monoclonal antibodies are being tested in clinical trials for cancer patients and osteoporotic post-menopausal women. WNT-targeting therapeutics have also been applied as reagents for in vitro stem-cell processing in the field of regenerative medicine.

Deficiency of pigment epithelium-derived factor in nasopharyngeal carcinoma cells triggers the epithelial-mesenchymal transition and metastasis

Distant metastasis is the primary cause of nasopharyngeal carcinoma (NPC) treatment failure while epithelial-mesenchymal transition (EMT) is the critical process of NPC invasion and metastasis. However, tumor-suppressor genes involved in the EMT and metastasis of NPC have not been explored clearly compared with the oncogenes. In the present study, the expression of pigment epithelium-derived factor (PEDF), a potent endogenous antitumor factor, was diminished in human NPC tissues and associated with clinicopathological and EMT features. The knockdown of PEDF induced EMT in lower metastatic NPC cell lines and overexpression of PEDF restored epithelial phenotype in higher metastatic NPC cell lines with typical EMT. The inhibition of PEDF mediated NPC cell spontaneous metastasis in vivo. LRP6/GSK3β/β-catenin signal pathway rather than AKT/GSK3β pathway was involved in the effects of PEDF on EMT. The expression of PEDF was directly downregulated by elevated miR-320c in NPC. In conclusion, our findings indicate for the first time that PEDF functions as tumor-suppressor gene in the occurrence of EMT and metastasis in NPC. PEDF could serve as a promising candidate for NPC diagnosis, prognosis and treatment.