The Tumor Suppressor CYLD Inhibits Mammary Epithelial to Mesenchymal Transition by the Coordinated Inhibition of YAP/TAZ and TGF Signaling

Loss of CYLD promotes splenic marginal zone lymphoma

Splenic marginal zone lymphoma (SMZL) is a distinct clinical and pathological entity among marginal zone lymphomas. Genetic and microenvironmental factors leading to aberrant activation of the NF-κB pathway have been implicated in SMZL pathogenesis. CYLD is a negative regulator of NF-κB and other signaling pathways acting as a deubiquitinase of regulatory molecules and has been reported as a tumor suppressor in different types of cancer, including B-cell malignancies. To assess whether CYLD is implicated in the natural history of SMZL, we profiled primary cells from patients with SMZL and SMZL cell lines for CYLD expression and functionality. We report that CYLD is downregulated in patients with SMZL and that CYLD ablation in vitro leads to NF-κB pathway hyperactivation, promoting the proliferation of SMZL cells. In addition, we found that CYLD deficiency was associated with increased migration of SMZL cells in vitro, through CCR7 receptor signaling, and with increased dissemination in vivo. CYLD loss was sufficient to induce BcR signaling, conferring increased resistance to ibrutinib treatment in vitro. In summary, our work uncovers a novel role of CYLD as a key regulator in SMZL pathogenesis, dissemination, and resistance to targeted agents. On these grounds, CYLD could be proposed as a novel target for patient stratification and personalized interventions.

Grading Challenges and Prognostic Insights in Chromophobe Renal Cell Carcinoma: A Retrospective Study of 72 Patients

Chromophobe RCC (ChRCC) carries the best prognosis among all RCC subtypes, yet it lacks a proper grading system. Various systems have been suggested in the past, causing much controversy, and Avulova et al. recently proposed a promising four-tier grading system that takes into consideration tumor necrosis. Dysregulation of the mammalian target of the rapamycin (mTOR) pathway plays a key role in ChRCC pathogenesis, highlighting its molecular complexity. The present retrospective study aimed to evaluate the prognostic factors associated with a more aggressive ChRCC phenotype. Materials and Methods: Seventy-two patients diagnosed with ChRCC between 2004 and 2017 were included in our study. Pathology reports and tissue blocks were reviewed, and immunohistochemistry (IHC) was performed in order to assess the expressions of CYLD (tumor-suppressor gene) and mTOR, among other markers. Univariate analysis was performed, and OS was assessed using the Kaplan-Meier method. Results: In our study, 74% of patients were male, with a mean age of 60 years, and the mean tumor size was 63 mm (±44). The majority (54%) were followed for more than 10 years at intervals ranging between 44 and 222 months. The risk of death was significantly higher for patients that were classified as Grade 4 in the Avulova system (HR: 5.83; 95% CI, 1.37-24.7; p: = 0.017). As far as the IHC is concerned, mTOR expression was associated with an HR of 8.57 (95% CI, 1.91-38.5; p = 0.005), and CYLD expression was associated with an HR of 17.3 (95% CI, 1.57-192; p = 0.02). Conclusions: In our study, the Avulova grading system seems to be positively correlated with OS in patients diagnosed with ChRCC. Furthermore, an elevated mTOR expression also shows a negative correlation with OS, whereas an elevated CYLD expression does not seem to exert a protective role. However, because only a small proportion (4.2%) of our patients died due to ChRCC, despite the long follow-up period, the results must be interpreted with caution. Further research is needed to validate our findings.

Inactivation of Tumor Suppressor CYLD Inhibits Fibroblast Reprogramming to Pluripotency

CYLD is a tumor suppressor gene coding for a deubiquitinating enzyme that has a critical regulatory function in a variety of signaling pathways and biological processes involved in cancer development and progression, many of which are also key modulators of somatic cell reprogramming. Nevertheless, the potential role of CYLD in this process has not been studied. With the dual aim of investigating the involvement of CYLD in reprogramming and developing a better understanding of the intricate regulatory system governing this process, we reprogrammed control (CYLDWT/WT) and CYLD DUB-deficient (CYLDΔ9/Δ9) mouse embryonic fibroblasts (MEFs) into induced pluripotent stem cells (iPSCs) through ectopic overexpression of the Yamanaka factors (Oct3/4, Sox2, Klf4, c-myc). CYLD DUB deficiency led to significantly reduced reprogramming efficiency and slower early reprogramming kinetics. The introduction of WT CYLD to CYLDΔ9/Δ9 MEFs rescued the phenotype. Nevertheless, CYLD DUB-deficient cells were capable of establishing induced pluripotent colonies with full spontaneous differentiation potential of the three germ layers. Whole proteome analysis (Data are available via ProteomeXchange with identifier PXD044220) revealed that the mesenchymal-to-epithelial transition (MET) during the early reprogramming stages was disrupted in CYLDΔ9/Δ9 MEFs. Interestingly, differentially enriched pathways revealed that the primary processes affected by CYLD DUB deficiency were associated with the organization of the extracellular matrix and several metabolic pathways. Our findings not only establish for the first time CYLD's significance as a regulatory component of early reprogramming but also highlight its role as an extracellular matrix regulator, which has profound implications in cancer research.

Suspension state and shear stress enhance breast tumor cells EMT through YAP by microRNA-29b

Except for biochemical effects, suspension state (Sus) is proved to induce epithelial-mesenchymal transition (EMT) of circulating tumor cells (CTCs) mechanically. However, the difference between the effects of the mechanical microenvironment in capillaries (simplified as shear stress (SS) and Sus) and single Sus on EMT is unclear, nor the underlying mechanism. Here, breast tumor cells (BTCs) were loaded with Sus and SS to mimic the situation of CTCs stimulated by these two kinds of mechanics. It was demonstrated that the EMT of BTCs was enhanced by Sus and SS and the mechanotransductor yes-associated protein (YAP) was partially cytoplasmic stored with microRNA (miR)-29b decreased, which was detected by miR sequencing. Though it couldn't possess a feedback regulation, YAP promoted miR-29b expression and posttranscriptionally regulated BTCs EMT through miR-29b, where transforming growth factor β involved. Analysis of clinical database showed that high miR-29b expression was beneficial to high survival rate stabilizing its role of tumor suppressor. This study discovers the mechanism that Sus and SS promote BTCs EMT by YAP through miR-29b posttranscriptionally and highlight the potential of YAP and miR-29b in tumor therapy. The combination of suspension state and shear stress promotes transforming growth factor β involved epithelial-mesenchymal transition by yes-associated protein through microRNA-29b.

MiR-182-5p Is Upregulated in Hepatic Tissues from a Diet-Induced NAFLD/NASH/HCC C57BL/6J Mouse Model and Modulates Cyld and Foxo1 Expression

Non-alcoholic fatty liver disease (NAFLD) is considered a relevant liver chronic disease. Variable percentages of NAFLD cases progress from steatosis to steatohepatitis (NASH), cirrhosis and, eventually, hepatocellular carcinoma (HCC). In this study, we aimed to deepen our understanding of expression levels and functional relationships between miR-182-5p and Cyld-Foxo1 in hepatic tissues from C57BL/6J mouse models of diet-induced NAFL/NASH/HCC progression. A miR-182-5p increase was detected early in livers as NAFLD damage progressed, and in tumors compared to peritumor normal tissues. An in vitro assay on HepG2 cells confirmed Cyld and Foxo1, both tumor-suppressor, as miR-182-5p target genes. According to miR-182-5p expression, decreased protein levels were observed in tumors compared to peritumor tissues. Analysis of miR-182-5p, Cyld and Foxo1 expression levels, based on datasets from human HCC samples, showed results consistent with those from our mouse models, and also highlighted the ability of miR-182-5p to distinguish between normal and tumor tissues (AUC 0.83). Overall, this study shows, for the first time, miR-182-5p overexpression and Cyld-Foxo1 downregulation in hepatic tissues and tumors from a diet-induced NAFLD/HCC mouse model. These data were confirmed by the analysis of datasets from human HCC samples, highlighting miR-182-5p diagnostic accuracy and demonstrating the need for further studies to assess its potential role as a biomarker or therapeutic target.

Endothelial FAT1 inhibits angiogenesis by controlling YAP/TAZ protein degradation via E3 ligase MIB2

Activation of endothelial YAP/TAZ signaling is crucial for physiological and pathological angiogenesis. The mechanisms of endothelial YAP/TAZ regulation are, however, incompletely understood. Here we report that the protocadherin FAT1 acts as a critical upstream regulator of endothelial YAP/TAZ which limits the activity of these transcriptional cofactors during developmental and tumor angiogenesis by promoting their degradation. We show that loss of endothelial FAT1 results in increased endothelial cell proliferation in vitro and in various angiogenesis models in vivo. This effect is due to perturbed YAP/TAZ protein degradation, leading to increased YAP/TAZ protein levels and expression of canonical YAP/TAZ target genes. We identify the E3 ubiquitin ligase Mind Bomb-2 (MIB2) as a FAT1-interacting protein mediating FAT1-induced YAP/TAZ ubiquitination and degradation. Loss of MIB2 expression in endothelial cells in vitro and in vivo recapitulates the effects of FAT1 depletion and causes decreased YAP/TAZ degradation and increased YAP/TAZ signaling. Our data identify a pivotal mechanism of YAP/TAZ regulation involving FAT1 and its associated E3 ligase MIB2, which is essential for YAP/TAZ-dependent angiogenesis.

The Hippo Pathway Effector Transcriptional Co-activator With PDZ-Binding Motif Correlates With Clinical Prognosis and Immune Infiltration in Colorectal Cancer

The transcriptional co-activator with PDZ-binding motif (TAZ) is a downstream effector of the Hippo pathway. It has been identified as an oncogene in certain tumor types; however, the function and role of TAZ in colorectal cancer (CRC) has not been illustrated. Here, we aimed to analyze the expression and role of TAZ in CRC. In this study, we investigated the expression level of TAZ in 127 CRC and matched adjacent normal tissues by immunohistochemistry (IHC) and analyzed its correlation with clinicopathological characteristics in CRC. Moreover, we further analyzed the role of TAZ in the CRC-associated immunology using integrative bioinformatic analyses. The cBioPortal and WebGestalt database were used to analyze the co-expressed genes and related pathways of TAZ in CRC by gene ontology (GO) and KEGG enrichment analyses. Meanwhile, the correlations between TAZ and the infiltrating immune cells and gene markers were analyzed by TIMER database. Our study revealed that TAZ expression is higher in CRC tissues than in matched adjacent non-tumor tissues. In addition, CRC patients with higher TAZ expression demonstrated poor overall survival (OS) and recurrent-free survival rates as compared to CRC patients with lower expression of TAZ. Furthermore, the TAZ expression was identified to closely associate with the immune infiltration of CD4 + T, CD8 + T, and B cells. Taken together, our findings suggest that TAZ may serve as a promising prognostic biomarker and therapeutic target in CRC.

Knockout of Calcyclin Binding Protein Impedes the Growth of Breast Cancer Cells by Regulating Cell Apoptosis and β-Catenin Signaling

Breast invasive carcinoma (BRCA) is becoming the most common malignant disease worldwide, and there is intense interest in identifying diagnostic biomarkers that can be targeted for treatment of BRCA. Recent evidence has shown that calcyclin binding protein (CacyBP) can function as either a tumor promoter or suppressor during carcinogenesis. Data in The Cancer Genome Atlas (TCGA) database show that CacyBP is overexpressed in human BRCA tissues, and high levels of CacyBP are associated with shorter overall survival. Immunohistochemical staining has shown that CacyBP levels are high in cancer tissue samples and associated with a higher likelihood of disease progression. We, therefore, conducted a knockout assay to determine the role of CacyBP in the development of BRCA. Knockout of CacyBP significantly inhibited MCF7 cell proliferation and colony formation. Apoptosis was higher in CacyBP knockout cells compared with control cells. Microarray analysis showed that the CacyBP knockout caused dysregulation of numerous genes closely related to β-catenin signaling, whereas quantitative reverse-transcription PCR and immunoblotting showed that it to be inactivated. In summary, we conclude that when overexpressed, CacyBP acts as a potential oncogene for BRCA by regulating β-catenin signaling.

Cytokeratin 5 determines maturation of the mammary myoepithelium

At invasion, transformed mammary epithelial cells expand into the stroma through a disrupted myoepithelial (ME) cell layer and basement membrane (BM). The intact ME cell layer has thus been suggested to act as a barrier against invasion. Here, we investigate the mechanisms behind the disruption of ME cell layer. We show that the expression of basal/ME proteins CK5, CK14, and α-SMA altered along increasing grade of malignancy, and their loss affected the maintenance of organotypic 3D mammary architecture. Furthermore, our data suggests that loss of CK5 prior to invasive stage causes decreased levels of Zinc finger protein SNAI2 (SLUG), a key regulator of the mammary epithelial cell lineage determination. Consequently, a differentiation bias toward luminal epithelial cell type was detected with loss of mature, α-SMA-expressing ME cells and reduced deposition of basement membrane protein laminin-5. Therefore, our data discloses the central role of CK5 in mammary epithelial differentiation and maintenance of normal ME layer.