MiR-139-5p Loss-Mediated WTAP Activation Contributes to Hepatocellular Carcinoma Progression by Promoting the Epithelial to Mesenchymal Transition

Wilms' tumor 1-associating protein (WTAP) is ubiquitously expressed in many tissues and plays an important role in physiological processes and tumor development. Here, we investigated the specific biological role and underlying mechanism of WTAP in melanoma. We determined the expression of WTAP and its correlation with clinicopathological features in paraffin-embedded tissues. We investigated the effects of WTAP on melanoma cells via a CCK-8 assay, a colony formation assay, an EdU assay, a Transwell assay, and subcutaneous xenograft experiments. We then applied RNA sequencing to further screen candidate targets, and NT5E was selected as the downstream gene of WTAP. Finally, a series of rescue assays, together with nucleotidase assays and ELISA, were adopted to confirm the function of NT5E in melanoma progression. We demonstrated that WTAP expression was downregulated in melanoma, which was associated with a poor prognosis, and that WTAP expression served as an independent predictor of melanoma survival. Functionally, WTAP hindered the proliferation, growth, migration, and invasion of melanoma cells. Furthermore, NT5E was identified as the downstream effector of WTAP and was subsequently found to rescue the increased proliferation, migration, and invasion of melanoma cells induced by WTAP deficiency. Moreover, knockdown of WTAP increased the expression of NT5E, MMP2, and N-cadherin, and simultaneous transfection with siNT5E reversed the increased expression of MMP2 and N-cadherin. Moreover, increased NT5E expression caused by forced WTAP inhibition in melanoma promoted the hydrolysis of AMP to produce more adenosine and further abrogated the secretion of IFN-γ by PBMCs. We found that WTAP expression is significantly downregulated and restrains the progression of melanoma via the downstream effects of NT5E on immunosuppression and molecular adhesion. This study revealed that WTAP plays a crucial inhibitory role in melanoma oncogenesis and highlighted WTAP as a potential novel diagnosis and therapeutic target for melanoma.

Acute myeloid leukemia (AML) is a heterogenous disease and the survival of AML patients is largely attributed to the improvement of supportive treatment. Wilms' tumor 1-associated protein (WTAP) is a nuclear protein functions in many physiological and pathological processes. Although its expression and function in many malignant diseases have been reported, its prognostic and epigenetic roles in AML are largely unknown. Peripheral blood or bone marrow samples were collected from AML patients. The WTAP expression was detected by western blot. WTAP expression level and patients clinical features were analyzed using statistical methods. WTAP knockdown AML cells were constructed. The experiments on proliferation, tumorigenic ability, cell cycle, and apoptosis were performed. Transcriptome sequencing was performed and analyzed. M6A methylation level was measured and m6A-RIP was performed to quantify m6A methylation level of MYC mRNA. RNA stability assay was performed to measure the half-life of mRNA. WTAP was overexpressed in AML patients and was an independent poor-risk factor in AML (p = 0.0140). Moreover, we found that WTAP regulated proliferation, tumorigenesis, cell cycle, and differentiation of AML cells. Furthermore, WTAP made AML cells resistant to daunorubicin. In further investigations, m6A methylation level was downregulated when knocking down WTAP, and c-Myc was upregulated due to the decreased m6A methylation of MYC mRNA. High WTAP expression predicts poor prognosis in AML and WTAP plays an epigenetic role in AML.

Wilms' tumor 1-associating protein (WTAP) interacts with the Wilms' tumor 1 gene. Although originally classified as a tumor suppressor, WTAP was later found to be over-expressed in glioblastoma which is regarded as a grade IV astrocytoma. However, the expression in other glioma grades and the relationship between WTAP expression and the prognosis of glioma patients are still unknown. In this study, we investigated WTAP expression in 169 different types of glioma cases using western blot analysis and immunohistochemistry assay. Further, we evaluated the association of WTAP expression with clinicopathological characteristics using chi-square test and Spearman's correlation test. We used univariate and multivariate Cox regression analyses to evaluate the independency of diferent WTAP expression. Then, the survival curves were calculated using the Kaplan-Meier method. Results showed that WTAP was over-expressed in glioma tissues, and the expression was closely correlated with glioma grade. Moreover, high WTAP expression was correlated with poor postoperative survival in glioma patients. WTAP may serve as a novel prognostic marker.

Apoptosis of vascular smooth muscle cells (SMC) is a culprit event in atherosclerotic plaque destabilization. We recently discovered that Wilms’ tumor 1-associating protein (WTAP) is a dynamically expressed transcriptional regulator that can be pro-apoptotic for human SMCs (Circ Res, 2006). To identify upstream regulators of this nuclear protein, we screened growth factors for their capacity to impact WTAP expression and found that insulin-like growth factor-1 (IGF-1), a potent survival factor for SMCs, stimulated a striking decline in WTAP protein abundance, to 10% at 12 h. We further determined that this decline in WTAP was due specifically to WTAP protein degradation, established by pulse-chase analysis of 35 S-labeled WTAP and the absence of an acute effect of IGF-1 on WTAP mRNA abundance. IGF-1-mediated WTAP degradation was blocked by two mechanistically distinct IGF-1 receptor inhibitors (picropodophyllin and PQ401) and by inhibition of phosphatidylinositol 3 (PI3)-kinase but not by MEK inhibition. In addition, IGF-1 induced the association of WTAP with ubiquitin, established by coimmunoprecipitation, and the downregulation of WTAP by IGF-1 was abrogated by inhibiting 26S proteasome activity with lactacystin or MG132. Interestingly, IGF-1 also stimulated phosphorylation of WTAP, that preceded the association of WTAP with ubiquitin, and hyperphosphorylation of WTAP through phosphatase-inhibition further accelerated WTAP degradation. Finally, to determine if WTAP downregulation was necessary for IGF-1-mediated SMC survival, surface expression of phosphatidylserine was quantified by flow cytometry of SMCs infected with retrovirus containing WTAP cDNA. Whereas IGF-1 enhanced the survival of vector-infected SMCs this was completely abrogated in WTAP-overexpressing SMCs. Conclusions: IGF-1-mediated SMC survival is dependent on the rapid depletion of WTAP from the nucleus, a degradation cascade that is heralded by WTAP phosphorylation. This WTAP phosphorylation and clearance response represents a novel consequence of PI3-kinase activation and highlights WTAP as a key negative regulator of SMC survival during vascular remodeling.

Background: Wilms tumor 1-associated protein (WTAP) plays a critical role in ribonucleic acid (RNA) methylation of N6 adenosine (m6A) modification, which is closely related with varieties of biological process. However, the role of WTAP in cancers remains to be determined. This study is designed to demonstrate the prognostic landscape of WTAP in pan-cancer and explore the relationship between WTAP expression and immune infiltration.Methods: Here, we investigated the expression level and prognostic role of WTAP in pan-cancer using multiple databases, including PrognoScan, GEPIA, and Kaplan-Meier Plotter. Then, applying the GEPIA and TIMER databases, we illustrated the correlations between WTAP expression and immune infiltration in tumors, especially liver hepatocellular carcinoma (LIHC), and esophageal carcinoma (ESCA).Results: WTAP had significant higher expression levels in tumor tissues of ESCA, LIHC, etc., while lower expression levels in those of bladder urothelial carcinoma (BLCA), breast invasive carcinoma (BRCA), etc. And WTAP demonstrated multifaceted prognostic value in cancers. Of our interests, WTAP exerted a harmful effect on LIHC patient for overall survival (OS) and progression free survival (PFS). WTAP expression also significantly associated with the infiltration levels of B cells, CD8+ T cells, CD4+ T cells, macrophages, neutrophils, and dendritic cells (DC) in LIHC but not ESCA. Furthermore, combined analysis about WTAP expression level and immune cell specific gene markers implied WTAP correlates with regulatory cells (T reg) infiltration in LIHC and ESCA.Conclusion: The m6A regulator WTAP can serve as a prognostic biomarker for certain tumor types in pan-cancer and potentially result from immune cell infiltration.

Wilms' tumor 1-associated protein (WTAP), a component of the m6A methyltransferase complex, recruits the m6A methyltransferases METTL3 and METTL14 to the corresponding mRNA targets to participate in the formation of N6-methyladenosine. However, the molecular mechanism of WTAP in the tumorigenesis and progression of nasopharyngeal carcinoma (NPC) remains unclear. This study aimed to explore the prognostic value and biological function of WTAP in NPC. We assessed WTAP expression and its prognostic significance using microarray datasets from the Gene Expression Omnibus (GSE12452) database and 100 NPC tissues via bioinformatics analysis and immunohistochemistry (IHC), respectively. Moreover, gene ontology (GO) and gene set enrichment analysis (GSEA) were performed. In addition, the correlation of WTAP expression with the expression of immune cell biomarkers was analyzed. The results showed that WTAP expression was significantly overexpressed in NPC tissues in GSE12452. The overexpression of WTAP was validated by the external datasets including NPC tissues (GSE150430) and NPC cell lines (GSE39826). GO analysis suggested enrichment in the nucleoplasm (cellular component) and cell cycle (biological process). The GSEA revealed that differentially expressed genes were enriched in E2F-targets, Myc_targets_v1, G2M checkpoint, Myc_targets_v2, and Interferon-alpha-response. In IHC analysis, WTAP was upregulated in NPC tissues, and high levels of WTAP expression were significantly correlated with the advanced T stage (p=0.047) and advanced N stage (p=0.018). Cox regression demonstrated that WTAP overexpression was an independent biomarker of poor prognosis for overall survival (hazard ratio [HR], 4.747; 95% confidence interval [CI], 1.671-13.482; p=0.003). In IHC analysis, the expression of WTAP was positively correlated with CD206 (biomarker for M2 macrophages) (p=0.018) but negatively correlated with CD8a (biomarker for cytotoxic T cells) (p=0.001). In conclusion, WTAP is a promising prognostic biomarker and may participate in the regulation of immune cell infiltration in NPC.

Castration-resistant prostate cancer (CRPC) is one of the most prevalent cancers in men. The new generation androgen receptor (AR) inhibitor enzalutamide can improve the therapeutic effectiveness of patients with CRPC. However, these patients eventually develop acquired enzalutamide resistance (ENZR), and the mechanisms underlying resistance are not well understood. Wilms' tumor 1-associating protein (WTAP) plays an important role in m6A modification and has been reported as an oncogene in various cancers. Here, we utilized a tissue microarray and collected tissues from prostate cancer (PCa) patients to detect WTAP expression, and found that WTAP is upregulated in PCa. Meanwhile, WTAP overexpression promotes cell proliferation and accelerates tumor growth through colony formation assays and the establishment of a subcutaneous xenograft model in vivo. These findings establish the tumor promoter role of WTAP in prostatic tumorigenesis. Furthermore, we verified that WTAP is a novel responsive gene of AR via promoter activity and chromatin immunoprecipitation (ChIP) assays. Importantly, we uncovered that WTAP is upregulated in ENZR cells, and WTAP knockdown inhibited the proliferation of ENZR cells. Mechanistically, ubiquitin-specific protease (USP7) enhanced the stability of WTAP by the ubiquitin-proteasome pathway in ENZR cells, thereby WTAP increases promote AKT signaling through an m6A-mediated way, and an AKT inhibitor can abolish the pro-resistance phenotype mediated by WTAP. Together, these findings suggest that WTAP plays a key role in ENZR development of PCa cells, and WTAP may be a potential treatment target for ENZR tumors. In this manuscript, we utilized a tissue microarray and collected tissues from prostate cancer (PCa) patients to detect WTAP expression, and found that WTAP is upregulated in PCa. Meanwhile, WTAP overexpression promotes cell proliferation and accelerates tumor growth through colony formation assays and the establishment of a subcutaneous xenograft model in vivo. These findings establish the tumor promoter role of WTAP in prostatic tumorigenesis. Furthermore, we verified that WTAP is a novel responsive gene of AR via promoter activity and chromatin immunoprecipitation (ChIP) assays. Importantly, we uncovered that WTAP is upregulated in ENZR cells, and WTAP knockdown inhibited the proliferation of ENZR cells. Mechanistically, ubiquitin-specific protease (USP7) enhanced the stability of WTAP by the ubiquitin-proteasome pathway in ENZR cells, thereby WTAP increases promote AKT signaling through an m6A-mediated way, and an AKT inhibitor can abolish the pro-resistance phenotype mediated by WTAP. Together, these findings suggest that WTAP plays a key role in ENZR development of PCa cells, and WTAP may be a potential treatment target for ENZR tumors.

This study aimed to analyze the functional roles and molecular mechanism of Wilms' tumor 1-associating protein (WTAP) in the tumorigenesis of nonsmall-cell lung cancer (NSCLC). Retrospective analysis was used. Tumor tissues and surrounding nontumor tissues of 150 patients with NSCLS who were surgically resected in the Fourth Hospital of Hebei Medical University from January 2016 to January 2018 were selected. The expression of WTAP in NSCLC tissues was detected by immunohistochemistry. Clinicopathologic parameters were then subjected to univariate and multivariate Cox regression analysis in purpose of uncovering the independent risk factors for overall survival time. MTS (3-[4,5-dimethylthiazol-zyl]-5-[3-carboxymethoxyphenyl]-2-[4-sulfophenyl]-2H-tetrazoliuzolium, inner salt) assay, colony formation assay, and transwell assays were performed to estimate cell proliferation, migration, and invasion. Meanwhile, the relationship between WTAP and the cell migration and invasion marker-related proteins were evaluated by Western blot analysis and RT-qPCR. WTAP expression was knocked-down in cell lines by shRNA, and RNA-Seq was performed to investigate the pathways regulated by WTAP. In NSCLC patients, WTAP was highly expressed in tumor tissues and the higher expression was significantly associated with poor overall survival (OS) ( P <0.01). Compared with the control group in vitro, the overexpression of WTAP could significantly promote cell proliferation, migration, and invasion ( P <0.01), while knock-down WTAP significantly reduces the above effects ( P <0.01). In a mouse orthotopic implantation model, higher WTAP abundance could significantly promote tumor enlargement compared with the control group ( P <0.01). Compared with the control group, the knock-down of WTAP significantly inhibit the expression of carcinoembryonic antigen-related cell adhesion molecule 5 (CEACAM5) in cell lines ( P <0.01). Besides, in NSCLC, knocked-down CEACAM5 significantly reduced the impact of WTAP on cell proliferation, migration, and invasion compared with the control group ( P <0.05). This study suggests that high expression of WTAP was associated with poor clinical outcomes. CEACAM5 may play a synergistic role with WTAP to jointly promote NSCLC progression by enhancing cell proliferation, invasion, and migration.

Hepatocellular carcinoma (HCC) often requires targeted therapy and immunotherapy due to frequent delayed diagnosis. Sorafenib, the first targeted drug applied to treat HCC, has demonstrated a remarkable therapeutic effect in the clinic. However, its clinical application has been limited by drug resistance and the insufficient understanding of the relevant mechanism. Wilms' tumor 1-associated protein (WTAP), associated with tumor progression, remains unstated in sorafenib resistance. In this study, WTAP expression patterns in HCC were systematically characterized through integrative analysis of The Cancer Genome Atlas (TCGA) datasets and spatial transcriptomic profiling. To delineate the potential mechanisms of WTAP-mediated sorafenib resistance in HCC, multimodal approaches integrating gene set enrichment analysis (GSEA), predictions from the "oncoPredict" package in vitro experiments, molecular docking simulations, and western blot validation were applied. To further investigate the role of WTAP in drug resistance, hydrodynamic tail vein injection (HTVi) mouse models and immunohistochemistry were utilized. Significant WTAP upregulation was identified in HCC tissues, showing strong associations with tumor progression and adverse clinical outcomes. The knockdown of WTAP sensitized HCC cells to sorafenib in vitro. GSEA, molecular docking analysis, and western blot analysis demonstrated that WTAP induces the activation of the extracellular signal-regulated kinase (ERK) signaling pathway, a critical link in chemoresistance mechanisms. In the HTVi HCC model, the combination of WTAP knockdown with sorafenib markedly suppressed tumor progression and boosted survival rates. These findings highlight that WTAP positively regulates the ERK pathway in HCC, promoting sorafenib resistance; therefore, targeting WTAP may represent a novel strategy to potentiate sorafenib responsiveness in HCC.

Few reports exist regarding the expression and function of Wilms’ tumor 1-associated protein (WTAP) in colorectal cancer (CRC), and the evidence is controversial. Our analysis explored the expression of WTAP in CRC tissue, and analyzed its clinical and prognostic significance. WTAP expression was significantly higher in CRC tissue than in colorectal adenoma and normal colorectal tissue. WTAP was highest in left colon tumor samples and negatively associated with tumor differentiation, as well as depth of tumor invasion. In multiple logistic regression analysis, independent predictors of WTAP expression in CRC included tumor in the left colon (odds ratio = 2.634; 95% confidence interval: 1.129–6.142; P = 0.025) and poorly differentiated tissue (0.072; 0.014–0.367; P = 0.002). No clear relationship was observed between CRC patient prognosis and WTAP expression. We suggest that WTAP expression is upregulated in CRC, highly expressed in left colon cancer and negatively correlated with tumor differentiation.

BackgroundN6-methyladenosine (m6A) methylation, a well-known modification with new epigenetic functions, has been reported to participate in the tumorigenesis of hepatocellular carcinoma (HCC), providing novel insights into the molecular pathogenesis of this disease. However, as the key component of m6A methylation, Wilms tumor 1-associated protein (WTAP) has not been well studied in HCC. Here we investigated the biological role and underlying mechanism of WTAP in liver cancer.MethodsWe determined the expression of WTAP and its correlation with clinicopathological features using tissue microarrays and the Cancer Genome Atlas (TCGA) dataset. And we clarified the effects of WTAP on HCC cells using cell proliferation assay, colony formation, Edu assay and subcutaneous xenograft experiments. We then applied RNA sequencing combined with gene expression omnibus (GEO) data to screen candidate targets of WTAP. Finally, we investigated the regulatory mechanism of WTAP in HCC by m6A dot blot assay, methylated RNA immunoprecipitation (MeRIP) assay, dual luciferase reporter assay, RNA immunoprecipitation (RIP) assay and Chromatin immunoprecipitation (ChIP) assay.ResultsWe demonstrated that WTAP was highly expressed in HCC which indicated the poor prognosis, and that WTAP expression served as an independent predictor of HCC survival. Functionally, WTAP promoted the proliferation capability and tumor growth of HCC cells in vitro and in vivo. Furthermore, ETS proto-oncogene 1 (ETS1) was identified as the downstream effector of WTAP. The m6A modification regulated by WTAP led to post-transcriptional suppression of ETS1, with the implication of Hu-Antigen R (HuR) as an RNA stabilizer. Then ETS1 was found to inhibit the progression of HCC and could rescue the phenotype induced by WTAP deficiency. Moreover, WTAP modulated the G2/M phase of HCC cells through a p21/p27-dependent pattern mediated by ETS1.ConclusionWe have identified that WTAP is significantly up-regulated in HCC and promotes liver cancer development. WTAP-guided m6A modification contributes to the progression of HCC via the HuR-ETS1-p21/p27 axis. Our study is the first to report that WTAP-mediated m6A methylation has a crucial role in HCC oncogenesis, and highlights WTAP as a potential therapeutic target of HCC treatment.

Multiple myeloma (MM) remains incurable, largely owing to the lack of effective therapeutic targets. Wilms’ tumor 1-associated protein (WTAP) has been implicated in MM tumorigenesis, but its underlying molecular mechanisms remain unclear. This study aimed to elucidate the role of WTAP in MM progression. Bone marrow samples from newly diagnosed MM patients were analyzed. WTAP expression was assessed via Quantitative real-time PCR (qRT-PCR) and Western blot. Cell proliferation was evaluated using EdU and flow cytometry assays, while RNA immunoprecipitation (RIP) confirmed protein interactions. WTAP was overexpressed in MM patients and correlated with poor survival. Its knockdown significantly suppressed MM cell proliferation and inflammation. RIP assays identified MAP6D1 as a potential WTAP target. RNA-seq analysis suggested WTAP regulates MM proliferation via the Hippo signaling pathway. WTAP promotes MM proliferation by targeting MAP6D1 and modulating the Hippo pathway, highlighting its potential as a therapeutic target.

EBV downregulates the m6A “writer” WTAP in EBV-associated gastric carcinoma

Wilms' tumor 1-associating protein (WTAP), a core component of the N6-methyladenosine (m6A) methyltransferase complex, plays a crucial role in various biological processes. However, functional studies of WTAP in atherosclerosis development are largely unknown. Here, we demonstrate that WTAP expression was elevated in lipopolysaccharide (LPS)-stimulated macrophages and atherosclerotic lesions of apolipoprotein E-deficient (ApoE-/-) mice. To explore its functional role, we employed AAV8-mediated invivo knockdown and siRNA-mediated invitro silencing, which revealed that WTAP deficiency attenuated macrophage apoptosis and reduced atherosclerotic plaque formation. Mechanistically, we identified myosin heavy chain 11 (MYH11) as a mediator of WTAP-induced macrophage apoptosis. Notably, WTAP upregulated MYH11 expression in macrophages through an m6A-independent mechanism. These results delineate a new molecular paradigm that macrophage WTAP promotes macrophage apoptosis and atherosclerosis by increasing MYH11 expression, indicating that WTAP may be a potential therapeutic target against atherosclerosis.

Diagnostic value and immune infiltration characterization of WTAP as a critical m6A regulator in liver transplantation.